Gyula Klima:

Yale Lectures


(you may skip to the Contents from here)

The lectures presented here are the by-product of my teaching in Yale's Directed Studies program from 1991 through 1993 (hence the title, for want of a better). In fact, being what they are, lecture notes for an introductory philosophy course, they present rather elementary material. Yet, I flatter myself, they do not lack certain originality in the treatment of some of the basic questions of traditional metaphysics and epistemology. In any case, over the past couple of years they proved to be quite useful in teaching my several other courses, especially in medieval philosophy. Thus, being too elementary for transforming them into scholarly papers, on the one hand, yet, containing what I think to be both philosophically interesting and pedagogically useful ideas, on the other, I decided to publish them here, in the Net's formally less stringent medium. Here they can easily be accessed by people who think what they need is a clear and simple discussion of the intriguing philosophical points themselves, rather than the meticulous and sometimes cumbersome scholarly discussions of the texts that raised them (a description which fits, at least, the majority of my students). Given these considerations (as well as the author's lack of time), the lectures are presented here basically unedited, in the form as they were actually delivered, without any notes or references (disregarding the occasionally inserted page numbers, serving as reminders for myself, referring to the texts we used in class). However, anyone who is interested in the more detailed scholarly discussion of some of the topics touched upon here may wish to check some of the papers listed on my list of publications. (A number of items on that list are in Hungarian, so if you want to see the correct accents you need a properly configured browser with foreign language support for Latin 2 encoding. But if you don't read Hungarian, just don't bother.)

Contents (click here to go back to the top)



In this lecture I wish to lay out carefully the logical structure of Plato's arguments in his Phaedo, to lay bare, as it were, the logical skeleton of this dialectical organism, so that we can have a better understanding what, how and to what extent supports its principal conclusion: the immortality of the soul.

The need to support this conclusion arises in the context of the dialogue from Socrates's paradoxically sounding remark that a true philosopher should be more than willing to die. For a true philosopher, as he later explains, spends after all his whole life preparing, indeed, striving for death, the dissolution of the soul from the body.

Nothing is easier, commit suicide! - might sound the immediate reaction to such a view.

But this is forbidden by divine command, for we are put to this life by the gods, our masters, from whom we are not allowed to run away - sounds the answer of Socrates.

But if the gods are our good masters, only a fool would want to escape from them, and a philosopher should resent dying - objects Simmias.

In response to this objection, Socrates justifies the philosopher's wish to die with the hope that after death the soul migrates to a far better place.

This hope is reinforced by considering in how many ways the body is a bad place for the soul.

First of all,

(1) the body hinders the cognition of the soul - a major complaint of the philosopher who wishes, above all, to know.

That the body hinders the cognition of the soul is so

(a) because the body contributes to cognition only by the senses, which are "inaccurate witnesses".

(b) because the soul can discover true existence only in thought.

(c) because the ideas, the true essences of things, are the objects of thought, and not of perception.

(d) because thinking is actually hindered by the operations of the body.

Again, that the body is a bad place for the soul is also shown by the fact that

(2) the body is the source of all base desires, which are the cause of all kinds of injustice among people,

(a) because of its requirement of food and

(b) because of its passions: wants, lusts, fears, fancies and the rest, which are the commonest motives for bad actions.

So the real purification of the soul from all these bodily taints is nothing but her separation from the body altogether.

But already before the actual separation of these two, namely before death, the true philosopher is always occupied in the practice of dying, of severing the ties between body and soul.

Indeed, it is only through this practice that true virtue is attainable, since the common virtues of non-philosophers, not stemming from this practice, are not real virtues, and are, in a sense, contradictory.

Because, for example,

(a) non-philosophers are courageous only out of fear from a greater evil, and

(b) they are temperate only out of intemperance, for fear of losing other pleasures, but one can never have true virtue on the basis of having its opposite vice.

So as a consequence, it is only true philosophers who are really virtuous, and only they are the chosen few who will be capable of enjoying the pure intellectual pleasures of the soul, when it is finally released from the body.

But all this presupposes that the soul does not perish with death, as the body does.

Socrates sets about developing his arguments for this conclusion by referring to an "ancient doctrine", which holds that the souls after death "go from here to another world, wherefrom they return hither to be born again from the dead".

The first argument is designed to give rational support to this ancient doctrine, and runs as follows:

(P1) If the souls are born from the dead, then they must have existed in another world before their birth in this world

For a soul can come back from the dead only if it existed before birth. But before birth it did not exist in this world. So it must have existed in another.

(P2) Opposites are generated out of opposites

For whatever becomes something was not what it becomes, and whatever it becomes it was not before.

(P3) The opposite of living is being dead

Therefore, by (P2) and (P3), the living is generated from the dead. And so the living soul is generated from the dead. From which, by (P1), it follows that the souls must exist in another world before their birth in this world.

The trouble with this argument is the insufficient division provided by (P3). For by admitting that the opposite of living is being dead, and hence conceding that the living soul is generated from the dead, one excludes the possibility of the living soul's simply coming into existence when it is born in the body. Indeed, the principle that opposites are generated from opposites holds only with presupposing the permanent existence of some subject of these opposites. In the case of simple generation, however, that is, when something comes into existence that did not exist before, this principle does not hold, unless we understand "opposites" broadly, including contradictory opposites. But then, the opposite of "living" is "not living" and not "being dead", with the assumption of the dead existing in some other world. However, that the soul is not living before being born, of course, does not imply that it exists in a different world, the world of the dead, for it may simply not exist at all.

But not paying attention to this possible objection, Socrates proceeds to develop two auxiliary arguments. The first relies on the supposition of the completeness of nature, namely that

(AUX1) to each process there should correspond an opposite process, and hence, to dying the return to life.

Again, one may object that even if we accept the perhaps not self-evident principle of the completeness of nature, the opposite of dying need not be return to life, but may be simply being born, i.e., coming to exist.

Socrates's second auxiliary argument sounds as follows:

(AUX2) If the process of dying were not compensated by the opposite process of the return to life, then the whole process would end with all souls being dead.

The first problem with this argument is that there is nothing really impossible in the conclusion that the process of generation and corruption sometime will come to an end, so this conclusion need not force us to admit that to death there should correspond an opposite process of rebirth of the same souls in different bodies. But further, this conclusion follows, of course, only if there is a finite number of souls (which is after all plausible to suppose) and if no new souls come into existence, which, however, is a doubtful and unproven assumption.

So the above arguments all are based on the assumption that dying and being born are just transitions of the soul from one region of existents into another, without her perishing and coming to existence. Hence the need arises to prove this, namely that death is only the separation of the soul from the body, without her perishing, and that birth is just the union of the soul with the body, without her coming to be.

The first argument to prove this conclusion is drawn from the theory of recollection:

(R1) If learning in this life is recollecting what the soul knew before this life, then the soul existed before this life.

(R2) But learning in this life is recollecting what the soul knew before this life.

So, the soul existed before this life.

But, of course, further proof is needed to show that learning is recollection.

After a brief reminder of "the experimental proof" in Meno, Socrates develops another, independent argument.

(P1) What someone recollects he must have known at some previous time.

(P2) If someone, perceiving or recognizing and thus knowing something, knows also another, then he is said to recollect this other thing (being reminded, as it were, of it by the first one).

To introduce the third premise of his argument, Socrates puts forward some assumptions, which we are supposed to accept without further proof:

(Ass.1.) There are ideas.

(Ass.2.) Ideas are not the particulars sharing in them.

(Ass.3.) The particulars fall short of the ideas in perfection.

On the basis of these assumptions we may reasonably accept the third premise, namely that

(P3) when we recognize things as being more or less such and such, we also know the idea, which is perfectly such and such.

For we could not recognize something as being more or less such and such unless we knew that what is perfectly such and such, and that is the idea of being such and such, the existence and properties of which we conceded with the previous assumptions.

So, by (P2) and (P3), when we recognize things as being more or less such and such, we recollect the idea that is perfectly such and such. Whence, by (P1), we must have known the ideas at a previous time.

However, to recognize anything as such and such involves recollecting the corresponding idea in any sense experience. So we must have known the ideas before any sense experience. But it is since the time of our birth that we have sense experiences. So we must have known the ideas before our birth. Hence, either we have this knowledge also at birth and continue to have it during our life, or we lose it at birth, and need to be reminded of it. But experience shows that we do not have this knowledge at birth and afterwards. So we lost this knowledge at our birth, and we recover it in our present life by being reminded of it by the senses. But the recovering of lost knowledge is called recollection. So our learning from sense experience, which reminds us of our knowledge lost at our birth, is duly called recollection. Q.e.d.

The real strength of this argument is its addressing the problem of how our intellectual concepts function not only in abstract thinking, but even in sense experience. The point in (P3) is the valid observation that in order to recognize anything in sense experience as being such and such, we have to have a concept by which we can recognize the thing as such. (For example, an Amazonian Indian, living in the jungle, would probably not recognize, say, a credit card as such, while we probably would not recognize the edible and poisonous plants in his environment, which he easily recognizes as such.)

The problem with the argument, however, is its reliance on the doctrine of the ideas, presenting it as the only possible account for our having general concepts. For there may very well be also other ways of acquiring or generating our general concepts, indeed, also in this life, for example by abstraction, as we shall see this in Aristotle's account of the matter. But then our prenatal acquaintance with the ideas is not necessarily required for explaining how we can have general concepts in this life, and so how we can recognize things as falling under this or that general concept. Indeed, the claim that our general concepts are involved in any sense experience, and that hence we have to have them from our birth may well be simply false. Children need to be taught to recognize things as being such and such, and if we don't have to presuppose their prenatal acquaintance with ideas, then their learning may involve genuine concept acquisition, rather than mere recollection.

As a corollary, however, it does follow from the above conclusion, according to which learning is recollection of prenatal knowledge, that our souls existed before our birth. For from the previous argument it appears that our souls could have acquired knowledge of the ideas, that is, our universal concepts, only before birth.

Unless - objects Simmias - they are given to us at birth.

But since in the previous argument it was also conceded that they are lost at birth, the objection is dismissed as frivolous.

A further worry emerges, however, from the consideration that the previous argument proved only the pre-existence of the soul before birth. However, what we were originally concerned with was its enduring existence after death! How do we know that the soul, even if it existed before birth, will not cease to exist with death?

But, as Socrates points out immediately, the previous argument, relying on the doctrine of recollection, together with the first argument, which showed that the living are born from the dead, imply the required conclusion, the immortality of the soul.

For if a given soul should exist before the birth of a given man, so that he will be able to recollect in his lifetime, and this soul is born from the dead, then it must have been the soul of someone who had died before, and so it must have survived the death of that person. And this, we may suppose, is so in any arbitrarily chosen case. Whence, the soul, generally speaking, should survive the death of the human person whose soul it is, that is to say, it is immortal.

But, in case anybody is still daunted by the childish fear that the soul gets somehow scattered after death, like fume blown away in the wind, Socrates supplies a further argument to show that the soul is simply not of such a nature as to be easily scattered by the blow of death.

(1) What is uncompounded is incorruptible.

(2) Ideas are uncompounded, unchanging and incorruptible

(3) Unchanging things are invisible and can be perceived only with the mind

(4) There are two sorts of things, namely visible and invisible

(5) The soul is invisible

So the soul is more like the unchanging ideas, than the changing body, whence it is simple and incorruptible.

The main problem with this argument is again its reliance on the doctrine of ideas. However, with the assumption of the existence of the unchanging heaven of ideas, it is easy to see that the soul, being more akin to the eternal ideas than to corruptible bodies is likely to be incorruptible itself.

An important new element in this argument in contrast with the previous ones is its explicitly aiming at probability, rather than demonstrative certainty. Indeed, this stage of the dialogue seems to pave the way for introducing the kind of attitude to be taken, according to Plato (actually worded by Simmias), towards this type of investigation: even if one cannot attain geometrical certainty in the question, one should rationally weigh the probabilities of the possible opinions and choose the more probable and more honorable opinion. This impression is reinforced also by the argument immediately following, which uses a form of reasoning later "canonized" in Aristotelian dialectics as "locus a minori".

The argument runs as follows:

(1) The body is less likely to remain after death than the soul.

(2) But sometimes human bodies are preserved for centuries after death, as is seen in the case of mummies.

So the soul is much more likely to remain.

The argument, as it stands, is of course, not demonstrative, for it may very well be the case that despite appearances to the contrary the soul is in fact even more corruptible than the body. What gives this argument its force, however, is the dialectical maxim, tacitly assumed in the dialogue, namely that if a property belongs to something which is less likely to have it than something else, then this latter will have it too. It is this maxim, starting from the assumption of a lesser likelihood (a minori apparentia), that joins the phenomenon of the endurance of dead bodies to the conclusion of the incorruptibility of the soul. But it requires that the soul indeed appear to be more likely to endure than the body, so Socrates provides further confirmation of this likelihood by making probable guesses about how the relationship between individual bodies and souls influences the soul's qualities and individual fate. Since all these considerations point toward the conclusion that the more the soul immerses in the body the more deteriorated it becomes, it appears to be more likely that the soul is a nobler kind of entity than the body is, whence, since incorruptibility is nobler than corruptibility, it is less likely to decay after death than the body.

But, as I said, these arguments do not attain, and indeed, do not aim to attain demonstrative certainty. Plato is keen to make this obvious, and is evidently eager to show the right attitude he expects the reader to take towards them. Characteristically, he makes Simmias, who is about to raise a serious objection, formulate explicitly what one should think about these and other arguments in this matter:

"I feel myself (and I dare say that you have the same feeling) how hard or rather impossible is the attainment of certainty about questions such as these in the present life. And yet I should deem him a coward who did not prove what is said about them to the uttermost, or whose heart failed him before he had examined them on every side. For he should persevere until he has achieved one of two things: either he should discover, or be taught the truth about them; or, if this be impossible, I would have him take the best and most irrefragable of human theories, and let this be the raft upon which he sails through life - not without risk, as I admit, if he cannot find some word of God which will more surely and safely carry him."

But until one gets this divine word, one cannot but use one's reason and take into account the objections that can be raised against the previous arguments. The first of these is formulated by Simmias as follows:

(Obj.1. Simm) That the soul is invisible does not prove sufficiently that it is of the same unchangeable nature as the ideas, for there are other invisible things, like the harmony of the lyre, which are dependent for their existence on their material subject, and hence are even more corruptible than those.

I think the most notable thing about this objection is its "modernity". Indeed, it most clearly expresses a view about the nature of the human soul which one frequently meets in modern discussions. According to this conception what the name "soul" denotes is not some spiritual substance inhabiting the body, and thereby imparting life to it, but rather it is the specific organic structure of the living body, not having its own substantiality, but being present, when the body is so structured, and ceasing to be present, when this bodily structure ceases to be.

The other objection, formulated by Cebes, argues that even if the soul has its own substantiality, this may not be enough for its immortality.

(Obj.2. Cebes) For even if the soul is of such nature that it is capable of outwearing the body which it actually inhabits, nothing guarantees that it will outwear all bodies that it will subsequently assume.

In response to the first objection Socrates first points out that the assumption that the soul is a kind of harmony contradicts the previously accepted theory of recollection:


(1) If learning is recollection, then the soul pre-exists the body.

(2) If the soul is harmony, then it cannot pre-exist the body.

(3) But learning is recollection

So the soul cannot be harmony.

The only problem with this argument is its reliance on the theory of recollection. But two further responses intend to support the same conclusion on independent grounds.

Socrates's second response to the harmony-theory runs as follows:


(1) The soul is harmony


(2) Something that is harmony can be more or less harmonious


(3) nothing that is a soul can be more or less a soul

And so

(4) no soul is more or less harmonious than the other.


(5) a more harmonious soul would be a good soul, while a less harmonious soul would be an evil soul

Whence it follows that all souls are equally good or evil, which is false. So, having concluded to an evident falsity, we have to drop the assumption from which it followed, namely, that the soul is harmony.

This argument, unfortunately, simply does not conclude. For from the assumption that the soul is harmony and that a harmony can be more or less harmonious it simply does not follow that a more or less harmonious soul would be more or less a soul. So premise (3) (namely, that nothing that is a soul can be more or less a soul) does not exclude the possibility of there being souls that are more or less harmonious harmonies, unless we suppose that being a soul is just being a specific degree of harmony. But this is precisely what the upholders of the harmony theory would deny, when they claim that a more harmonious soul is a good soul and a less harmonious one is an evil one. So this argument does not refute the harmony theory.

Socrates's third response to the harmony-objection, put in a nutshell, is the following:

(1) Harmony does not rule its subject

(2) The soul does rule its subject, the body

So, the soul is not harmony.

The premise that the soul rules the body is evident from the everyday human experience that the soul can resist the desires and passions of the body, so it is the soul that will determine what the body should and will do, and not conversely.

However, despite the fact that the argument is valid, the justification of its dubious premise may not be entirely convincing. First of all, it is an equally common human experience that sometimes the soul yields to the passions of the body and nolens volens does what the body forces it to do.

To this, of course, one may easily answer that sometimes the soul is merely a weak ruler, but is, nevertheless, a ruler, which is shown by its mere capacity to rule, which would be out of the question, if the soul were just a harmony, a certain structural composition of the body.

On the other hand, one may question also this latter claim, and ask whether the above-mentioned human experience does indeed show the soul's capacity to rule, and whether this experience cannot be explained also on the basis of the assumption that the soul is after all but a certain kind of bodily structure. For one might as well say that when one resists bodily urges and desires all that happens is that certain urgent signals coming from one part of the body are simply suppressed by other bodily signals, and one need not suppose the activity of a spiritual substance residing in the body to explain what happens. For example, the heroism of people on a hunger-strike might be explained by the materialist by referring to nerve impulses coming from the cortex, which are responsible for these people's having such and such objectives, and which may be strong enough to suppress the nerve impulses coming from the vegetative nervous system. Since in such an explanation there need not be any reference to a spiritual soul governing the activities of the body, the above argument will not convince those who believe that the soul is just a certain specific bodily organization and what we describe as the activities of the soul are but certain activities of the body thus organized.

All these objections to Socrates's responses, however, do not prove that the harmony-theory is right. And in fact, the theory faces tremendous difficulties by its being committed to explaining human behavior exclusively in terms of bodily states.

This is precisely one of the topics taken up by Socrates introducing his final argument for the immortality of the soul, in answer to Cebes's objection.

After stating that this objection requires a general inquiry into the nature of causation and causal explanation, Socrates begins his discussion by telling about his dissatisfaction with the explanations of natural phenomena exclusively in terms of what Aristotle would call material and effective causes. Since, however, such explanations do not tell us anything about what things are for, to what end they work in the way they do, these explanations are certainly insufficient in the case of goal-directed phenomena, such as human actions and their means. But if also the whole natural world is goal-directed, obeying a divine ordination and government, then also natural phenomena are in need of teleological explanations, making clear how they fit into the great divine plan, directing everything to its proper end. It was precisely this idea that, according to the dialogue, attracted Socrates to the study of the works of Anaxagoras, who, however, beyond positing the world-governing Mind as the ultimate cause of all things, failed to give this type of explanations of natural phenomena. As a consequence, himself being unable to come up with the desired explanations, Socrates turned towards a simple, indeed, in his own description, simple-minded solution: the positing of ideas, and with this assumption giving explanations of phenomena in terms of what Aristotle would call their formal causes.

This type of explanation may be expressed schematically as follows:

If several things have a property F, then they have F because they share in the idea of F-ness itself

Even though this type of explanation in itself may not be very illuminating, nevertheless, if we couple it with the possible answers that one may give to the question: "what is F-ness?", then one can see how on the basis of such an explanation one may judge the validity of certain generalizations.

For example: on the basis of the above-mentioned principle, human beings are all humans in virtue of sharing in humanity. But supposing that humanity is nothing else but rationality coupled with animality, i.e., being human is nothing but being a rational animal, we can see that in virtue of being humans all of us are endowed with reason, even if this does not always and equally manifests itself in each and every case. The point in the above explanation, however, is that the individuals of the same species, despite all their individual variations, are in fact subject to certain valid generalizations, which renders the formulation of true universal claims about them possible.

To see that this is not an altogether trivial matter, consider an accidental collection of things, say the solid bodies in this classroom. Of these it is true that they all are extended. However, this is not true of them in virtue of their being in this classroom, but in virtue of their being bodies. So even if it happened to be so that in this classroom there were only extended things and there were no extended things outside this classroom, it would not necessarily be true that whatever is in this classroom is extended, while it is true that every body, whether in this classroom or not, is extended of necessity. And this, according to the explanation given above, is due to their sharing in the same idea of corporeity.

However, what makes this or that particular body subject to this necessary generalization is its own corporeity, its similitude to or share in the idea of corporeity. It is these and the like individualized properties that are responsible for the behavior of this or that particular individual, however, it is their being individual similitudes of the same universal idea that accounts for the universal traits of the behavior of all the individuals that have them.

Now whether or not we have any misgivings about the doctrine of ideas as being the only possible basis for valid necessary generalizations, the next point Socrates makes is certainly acceptable:

No individualized properties can change into their opposites.

Indeed, change occurs by a thing's exchanging one of its individualized properties for an opposite property, but it is never the property itself that changes into the opposite property. When a thing cools down, it exchanges its hotness for coldness, but it is not its hotness that changes into coldness, for its merely changing into its opposite would involve its remaining what it was: hotness. But nothing, while remaining hotness, can become coldness, even though what is hot can become cold remaining what it was, though definitely not remaining what it was like. What is hotness can become for example more or less intensive, but it can never lose its intensity so much as to turn into coldness while remaining what it was: hotness.

However, sometimes it is not only properties - argues Socrates further - that cannot change into their opposites, but also the things that bear these properties. Some things are so strongly stuck with some of their properties that they cannot, while remaining what they are and so remaining in existence, exchange them for their opposites.

Again, using later, scholastic, terminology we can say that Plato here introduces a distinction between essential and accidental properties:

(1) A property F is essential to a subject x if and only if x cannot lose F without ceasing to be what it is, i.e., ceasing to exist

A further postulate introduced by Socrates states a relationship between causation and essential properties:

(2) What is the cause of a property in other things has this property essentially

Now having all the general postulates of Socrates's theory at our disposal, we can add one particular premise regarding the soul, namely that

(3) the soul is the cause of life in any living thing

whence, by (2), it follows that the soul has life essentially. But then, by (1) the soul cannot lose life without ceasing to be what it is, namely, a soul.

This conclusion, however, is not what Plato intends to draw, namely that whatever is a soul cannot lose life altogether, unconditionally. For the above conclusion says only that whatever is a soul cannot lose life as long as it is a soul, which, however, leaves open the possibility that it loses life by ceasing to be a soul, that is, simply ceasing to be, just as fire can lose heat, by getting extinguished, i.e., ceasing to be fire, which is for it just ceasing to be.

On the other hand, one might try to save Plato's reasoning, by saying that since the soul's life is nothing but its existence, what the argument concludes to is the impossibility of the soul's emitting existence, which means that it will never cease to be, and hence will never cease to be what it is, namely a soul.

However, unfortunately, this defense will not do. For what the argument concludes to even with this addition is that the soul cannot lose its existence, without ceasing to be a soul. So all we can conclude to from these premises is that these three stand or fall together: (1) the soul's being a soul, (2) its being alive and (3) its being in existence. But concerning none of these can we conclude absolutely that it will belong always to what actually is a soul. What could prove this latter, would have to be some argument to the effect that what is actually a soul can never cease to be a soul, because being a soul is such a strong nature that simply cannot be destroyed. But this would only take us back to the dialogue's previous considerations about the divine nature of the soul, and so we seem to have made no progress.

But is this really so? Haven't we learned something fundamental about the soul and the possible considerations concerning its nature? Does the mere fact that Plato's arguments in this dialogue do not provide us with unshakable proofs of its intended conclusion render them worthless sophisms, not deserving any further attention? Does the fact that these arguments do not compel us to believe in the immortality of the soul mean that they have not provided us with reasons to choose to believe?

Unless, despite Plato's explicit warning, his readers have become misologues, giving up the reasoning game, and hence a part of their humanity altogether, the Phaedo's arguments will not cease to be a source of inspiration to anyone who wishes to think seriously about a subject that no human being can avoid thinking about sometime in this life: whether there is anything afterwards?


Porphyry's Introduction to Aristotle's Categories enjoyed immense popularity over several centuries. Its popularity, however, was not due to its intrinsic merits, its brevity, clarity and simplicity alone. For besides offering an ideal start-up for a course in Aristotelian logic, it also offered its commentators an opportunity to indulge in a discussion of one of the most intriguing of all metaphysical problems, the problem of universals. As John of Salisbury complained in his Metalogicon in the 12th century, teachers of logic of his time did not treat Porphyry's booklet properly, as an introduction, but, despite the author's expressed intention, they got involved in endless debates over metaphysical considerations, thereby "imposing an unbearable burden on the tender shoulders of their students".

But this indulgence, and sometimes over-indulgence in these debates, may perhaps be justified by more than sheer intellectual curiosity, or even intellectual pride, namely, by the intrinsic needs of a commentary. For a commentator of a text should in the beginning tell what the subject matter of his text is, what the text commented on is about. In the case of Porphyry's text, the answer seems to be simple. It's about universals. All right, but what on earth are universals? - ask the students immediately. And at this point, of course, a hell of further questions breaks loose.

Porphyry himself tries to get around these questions by simply listing them, and putting them aside for a "higher" investigation. His approach, in fact, is very much like that of some contemporary Oxford philosophers in that he just tries to describe what ordinary language usage tells us about universals, some simple facts on which everyone who speaks the language, indeed, any language, can agree, regardless of their metaphysical preferences. (Well, the big difference between him and our Oxford philosophers is that he puts forward these simple facts as preliminary to metaphysical considerations, not instead of them, as the latter would.) So, he describes a universal as something predicable of many things, which differ either specifically, in which case the universal is a genus, or numerically, in which case the universal is a species, provided they are predicable of something as an answer to the question: what is this? If it does not answer this question, then a universal is either still predicable essentially, in which case it is a specific difference, or it is predicable accidentally, but convertibly with a species, in which case it is a proprium, or simply accidentally, so that it may be true or not true of a subject without the perishing of the subject, in which case it is and accident.

So far, so good. But do these descriptions of the various kinds of universals give an answer to our commentators' question: what is this book about, what are the things thus described?

Well, all these descriptions involve the notion of predicability of many things, so no wonder in Latin Prophyry's work was often referred to as De Praedicabilibus, that is, On the Predicables. So this book, we can say, is about things that are predicable of many things. But, again, none of these descriptions tells us just what are the things that are predicable of many things. So Prophyry's roundabout approach could help our commentators only to be a little bit more specific when addressing the question of what his book is about, in that his descriptions told them that it's about things that are predicable of many, but did not help them much in avoiding the further questions stemming from his descriptions, concerning the nature of universals.

Now, to begin with, the obvious candidates for being the kind of things that are predicable of many things seem to be words. It is after all the word "man" that we can predicate of Socrates and Plato, and the word "animal" that we can predicate of donkeys and monkeys.

On the other hand, a word, whether written or spoken, seems to have nothing in itself that makes it predicable of many things, apart from what their users mean by them. A spatial series of ink-marks and a temporal series of sound-waves seem to be a word, indeed, the same word, only insofar as they express a concept, indeed, the same concept that speakers of a language associate with these sound-waves and with those ink-marks. In fact, users of different languages may have the same concept too, while they associate it with different sounds and different marks. What is more, even users of the same language may associate the same concept with different words, that is, with synonyms, or different concepts with the same word, in the case of an equivocal word. And so, in general, whether a word is predicable of this or that depends on the concept generally associated with it by the users of this word. But then, whether a word is predicable of many things or not depends on the kind of concept we associate with that word, namely whether the concept itself is universal or particular. So it seems that words are universal only insofar as they are associated with universal concepts, and so it is rather concepts that are primarily universal, and words are universal only on account of the universality of their concepts.

But then, if universals are primarily our concepts, namely acts of our minds by which we conceive of things, the question immediately arises how we can have these universal concepts, if the things from which we could acquire them, namely the things we perceive, are all particular?

Well, as we know, Plato's answer to this question was that it is not just particular, perceivable things from which we get our concepts. There are universal things, the ideas, and it is our direct, prenatal acquaintance with these that accounts for our universal concepts, while our experience of sensible particulars only helps us recover these universal concepts in this life, reminding us by their common features of the universal things they imperfectly imitate by these. So, from Plato's view we should conclude that universals primarily are these universal things, the ideas, for it is on account of their existence that our universal concepts exist, which then account further for our universal words.

Plato's answer, his theory of ideas and recollection, however, is flawed for several reasons, many of which were already spelled out by Plato himself in his Parmenides, such as the famous Third Man argument, which actually derives a contradiction from Plato's theory. From an Aristotelian point of view, however, the following consideration is of particular importance.

What do we mean by saying that Plato's ideas are universal, as opposed to the particulars, which participate in them? Well, what we mean by this is that they have just those properties which are common to several particulars from a certain aspect, but nothing else. For example, the idea of justice is only what belongs to justice insofar as justice, whereas just people and just acts have many other properties besides their justice, and so they can change with respect to those other properties, and even with respect to their justice. So a man or an act that is just here and now may be unjust elsewhere and at another time. For example giving an A on a good paper is a just act here and now, but in a reverse grading system, in which A is the worst grade, the same act would be unjust. But justice itself can never and nowhere cease to be justice and whatever belongs to justice insofar as justice, whence the idea of justice is unchangeable, and so eternal - says Plato.

But then, by the same token, the idea of triangle, for example, has to have only those properties that are common to all triangles, i.e., what belongs to a triangle insofar as a triangle. So, the idea of triangle should be triangular and also trilateral, for a triangle as such should be triangular and trilateral. And so it has to have three sides, for whatever is trilateral has to have three sides. And of these three sides either at least two have to be equal or all three must be unequal. So the idea of triangle has to be either isosceles or scalene, for any triangle, insofar as a triangle has to be either isosceles (i.e. having a pair of equal sides) or scalene (i.e. having no equal sides).

On the other hand, the idea of triangle cannot be scalene, for this would mean that a triangle insofar as a triangle would be scalene, whence all triangles would have to be scalene, and so no isosceles would be a triangle, which is false. And, by the same token, the idea of triangle cannot be isosceles either, for then whatever is a triangle should be isosceles, which is false again. But then the idea of triangle should be either isosceles or scalene and neither isosceles nor scalene, which is a contradiction. So nothing can be a universal triangle in the way just described, namely having all and only those properties that all particular triangles have in common, that is, what any triangle insofar as a triangle has.

But then, in general, no idea can be a universal thing in this way, namely having only those properties of their particulars which are common to them all, insofar as they all participate in this idea. For any such idea determines a range of further properties, some of which have to belong to anything that has the property exemplified by the idea, and so to the idea too; but none of these properties is such that it has to belong to everything having the property exemplified by the idea, so none of these can belong to the idea.

So, again, whatever is a man has to have some height, so the idea of man, being the perfect exemplification of the property "man", has to have some height too. But no particular height is such that what is a man has to have that height, for then every man should have the same height, i.e., they should all be equally tall, which is false. But then the idea of man cannot have any particular height, since it can have only those properties that belong equally to all humans, insofar as humans. So we arrive again at the contradiction that the idea of man has to have some height, but, at the same time, it can have no height.

Now Aristotle's ingenious solution to this problem of the universals lies in the observation that even if a man, for example, cannot be without any particular height, a man can be thought of without any particular height. To be sure, this must not be understood so that when we think of a man without any particular height, we would be thinking of a man who has no particular height, because that would imply thinking precisely of the impossibility we concluded to just now, namely that it is impossible that something should be a man without having any particular height, and so, such a thing is unthinkable. It is possible, however, to think of a man without any particular height in the sense that we can think of a man, while not thinking that the man has this particular height. For example, if I say, "Socrates is a man", then you certainly think of a man, Socrates, and by knowing that he is a man you also know that he has some particular height. You have no idea, however, what particular height he has. So even if you know that in virtue of being a man, Socrates has to be 6ft tall, or shorter, or taller, you certainly don't think that he is 5ft tall, or that he is 6ft tall or shorter or taller.

So even if no man can be without some particular height it is possible to think of a man without thinking of his particular height. But then, in general, we can conclude that it is possible to think separately of things, such as a man and his particular height, that cannot be separately. And this is precisely the point made by Boethius in his Commentary on Porphyry, namely that the intellect has the power to separate things which are together and cannot be separated in reality. So to think of a man in general, that is, to have and exercise the universal concept of man, does not mean to have our minds fixed on a universal man, i.e., a man that has all and only those properties that are common to all men, because that is impossible; but this rather means thinking of particular men in a universal manner, that is, thinking of them qua men and not thinking of those of their features that distinguish them. Now these latter distinguishing features are what later Aristotelians called "individuating conditions". Thinking of something without these individuating conditions in the manner just described, then, is what we call abstraction, the mental process by which we form our general concepts, that is, those mental acts by which we are able to conceive of particular things in a universal manner.

But then, we are already in a position to answer our question concerning the origin of our general concepts, without having to commit ourselves to the absurdities involved in the Platonic answer to this question. We acquire our general concepts from particulars by abstraction, separating in thought what cannot be separated in reality from their individuating conditions.

But what is it, then, that is so separated in thought, which could not be separated in the thing from these "individuating conditions"? Now this is what Aristotle calls the form of a thing, or at least one of the several forms that a thing has.

For forms according to Aristotle are of two basic types. Forms are either substantial forms or accidental forms. A substantial form of a thing is one that makes the thing that has this form actually existing, which means that for the thing to be is nothing but for it to have this form. An accidental form, on the other hand, makes a thing actual only in some respect, but, since for the thing to be is not for it to have this form, the thing may have or not have this form without perishing, which, as you recall, is just the way Porphyry defined accidents.

Now this conception of forms and the way they are related to our concepts has tremendous significance in epistemology, that is, in the theory of knowledge. For if for a thing to be is for it to have its substantial form, then this means that the thing will necessarily have all those of its attributes that it has in virtue of having this form, which we call its essential attributes, under all possible circumstances under which it exists at all. On the other hand, since by abstraction our intellects separate such forms from their individuating conditions in the particulars, by the resulting concept we shall be able to conceive all those things at once that have such a form, and attribute to all these things their essential attributes. So this conception can serve as a foundation for the possibility of our having universal and necessary knowledge, that is, scientific knowledge of the physical reality.

Unfortunately, however, not even this conception can guarantee that at any given time we are in possession of some particular piece of universal and necessary scientific knowledge. In fact, nowadays much of Aristotle's physics is irrevocably of the past. In view of what we know from modern chemistry, for example, nobody in their right mind would say that there are four elements in nature, one of which is water. Nowadays we just know (hopefully) that water is a compound consisting of H2O molecules.

On the other hand, should this kind of knowledge necessarily overthrow the general metaphysical framework of Aristotelianism? Should modern physics necessarily demolish the whole of Aristotelian metaphysics? On the contrary! The statement I just made, namely, that water is a compound consisting of H2O molecules, is precisely the kind of necessary, universal claim the validity of which could hardly be maintained without committing ourselves to some form of essentialism. For when we make this claim, we imply that this holds of any water sample at any time, under any possible circumstances. As long as something is water, it is a compound consisting of H2O molecules, that is to say, being a compound consisting of H2O molecules is an essential attribute of water.

To be sure, this claim is not necessarily true just because this is what we mean by the term "water". It was exactly the same kind of substance that was meant by users of the same term even before the discovery of water's chemical structure. Indeed, if this had somehow been implied in the meaning of this term, no chemical research would have been needed to make this discovery. So, since the necessity of such a scientific claim is not due to some linguistic convention (the commonly agreed meaning of the term "water"), it cannot be regarded as giving just a certain explication, a detailed description of our common concept of "water", accounting for the meaning of this term. Instead, we should say that it gives us an independent characterization of the thing that we conceived by this concept even previous to this scientific discovery.

But then, the necessary truth of this characterization depends on whether the thing so characterized does indeed necessarily have the attributes specified in this characterization, whether what is water is indeed necessarily a compound consisting of H2O molecules. Now Aristotelian essentialism does not tell us whether this particular characterization is in fact necessarily true or not. What it does tell us, however, is that there is some such characterization which, if it's correct, does necessarily and universally apply to the kind of things it characterizes.

To see this, consider the following. Aristotle tells us that things have substantial forms, that is, such forms that for the thing to be is nothing but for it to have such a form. It is such a form, however, which is abstracted from its individuating conditions when a substantial universal concept of the kind of thing in question is acquired. But the substantial attributes of things, that is, their species, genera, and differences, are precisely those terms which are predicable of them in virtue of being associated with such substantial concepts, and which, therefore, represent just these substantial forms. But then, these attributes are going to be true of these things just when they have the substantial forms represented by their corresponding concepts. But since for a thing to exist is to have such a substantial form, whenever such a thing exists, it will have such a form, and, consequently, whenever such a thing exists, its substantial attributes are going to be true of it. But this is precisely what is required for the universal and necessary validity of a scientific generalization concerning a kind of things. If the proper genus of water is truly the concept expressed by the term "compound", and if its specific difference is truly the concept expressed by the phrase "consisting of H2O molecules", then, since the genus and the specific difference are concepts abstracted from, and therefore representing, the substantial form of the thing, which the thing must have under any possible circumstances, provided it exists, this characterization will be true of anything that is water, under any possible circumstances under which it exists.

Now to see the significance of this result, suppose that things don't have substantial forms. This means that there is no such a form in a thing that for the thing to exist is to have that form. So, the same thing may have just any set of forms in any possible combinations, indiscriminately. But then, this would mean that of the same thing any possible combination of (compossible) terms could in principle be true. So even if we find that water is actually a compound consisting of H2O molecules, it is quite possible that the same thing will not be a compound consisting of H2O molecules in the next moment, or indeed, that the same thing which is now water will not be water. And this holds not only for this particular characterization, but for any other characterization whatsoever. So no universally and necessarily valid scientific claims can be made about the nature of things.

Abandoning essentialism, therefore, leads to an abandonment of necessary scientific truths. Embracing essentialism, on the other hand, guarantees only a possibility for science to make necessarily valid claims about nature, but, of course, it does not guarantee the correctness of any particular scientific claim. Now this is the reason why despite the fact that Aristotelian physics with its particular claims about nature is no longer tenable, Aristotelian metaphysics still lingers on in the discussions and attitudes of many contemporary scientists and philosophers, whom we may call scientific realists. Scientific realists view science just the way described, namely as supplying us with necessary and universal truths about the nature of things. But despite its appeal to scientific realists, the Aristotelian conception of essence, or substantial form is still puzzling even to these philosophers.

The source of this puzzlement is that contemporary philosophers tend to view essence as a sheer list of essential properties, or, rather, some obscure entity lurking behind the accidents of things, containing somehow only these essential properties. But this is precisely the wrong, Platonistic conception of essence, namely that of a thing containing only the essential properties of particulars. (And then, whether we think of such a thing as existing over and above, or only somehow inside the particulars is totally irrelevant, as we have just seen that such a thing cannot exist anyway, since supposing its existence leads to contradiction.)

However, keeping with the original, Aristotelian conception, there is nothing wrong with the concept of essence, or substantial form. According to this conception, a substantial form is something that we directly conceive by the substantial concepts of things (for we acquire these concepts precisely by abstracting substantial forms from their individuating conditions in the way I described). Therefore, to have the concept of, say, water, is not to have a set of properties in mind which something must have in order to qualify as water. If we have a substantial concept of a thing then by that concept we conceive the substantial form of the thing. If we have the concept of water, and this concept is a substantial concept of this kind of thing, then by this concept we conceive of the substantial form of water, for this form is precisely from where we acquired this concept, without having to rely on a set of identifying properties. But in virtue of having this concept we need not be able to re-identify this form by means of other concepts too, that is, we need not be able to provide the essential definition of water, which characterizes the same form, but by means of concepts other than the concept of water. Indeed, precisely because having the concept of water is not just having a set of identifying properties in mind, we can never arrive at an essential definition of water by just analyzing our concept of water, but this is a task of scientific research.

As a consequence, it is no wonder that Aristotelian essentialism could and did fail in science, as to many particular hypotheses Aristotle risked concerning the nature of things. On the other hand, the same Aristotelian essentialism need not have failed in the philosophy of science and in metaphysics, as to its most general principles concerning how our language and our concepts are related to the world, even if historically it did. But the actual historical defeat of Aristotelian metaphysics is a long and complicated story, which is a further issue in itself.


How is it possible that substances are good in that they are, although they are not substantially good? In his little treatise, "De Hebdomadibus", Boethius himself warns his reader of the obscurity of the question and of the abstruse character of the related speculations he is about to put forward. But the modern reader's puzzlement over his work probably exceeds by far anything that Boethius assumed.

Indeed, our puzzlement starts over the very title of the work. What can this strange phrase mean? To understand what it means and what its significance is, we have to know a little more also about its history. This title, translatable as: "Of Groups of Seven", was not given to the work by Boethius himself. It was introduced by medieval scribes for shorter reference, on account of Boethius's opening remarks concerning his "Hebdomades". But owing to the decline of Greek education, the medieval scribes and commentators of the work already had no idea of the significance of these remarks. The Greek phrase, "Hebdomades", meaning: "Groups of Seven", by all likelihood refers to a lost work whose main theses were gathered in groups of seven propositions put forward for meditation for every day of the week, entitled by Boethius "Hebdomades" probably in imitation of Plotinus's "Enneades", a work arranged by Plotinus's disciple, Porphyry, in groups of nine treatises. So it is probably concerning one of the theses contained in this lost work that Iohannes Diaconus (Boethius’s friend, who was to become Pope John I) asked for Boethius's fuller explanation, which Boethius provides in our little treatise.

That Boethius probably wrote a book after the model of Plotinus's work, while modifying the arrangement to meet Christian religious habits, whether it's actually true or not, has symbolic significance. For this expresses precisely what renders Boethius's thought of utmost historical importance: his grand plan of making the whole of Plato's and Aristotle's philosophy available to Latinity, along with commentaries showing their basic harmony, thereby continuing the Neo-Platonic tradition, and unifying their principles in a Christian theological synthesis. In the turbulent age of the fall of the Roman Empire, however, Boethius's plan was doomed to remain unfulfilled. Actually, Boethius was able to complete only a small fragment of his original plan. From Plato he managed to translate only the Timaeus. From Aristotle he translated and commented on the Categories and the Peri Hermeneias, while he also translated and commented on Porphyry's Isagoge, the Neo-Platonic thinker's Introduction to the study of Aristotle's Categories. Nevertheless, together with some short treatises in logic, on the seven liberal arts, some theological tracts, and his monument of philosophical courage, "The Consolations of Philosophy", written in jail waiting for his execution, these commentaries and translations had an enormous influence on medieval Western thought. For all these works exemplified the sort of striving for synthesis, rigor and conceptual unity that provided a model for generations of Christian thinkers throughout the Middle Ages.

In fact, it is only against the background of this conceptual unity that his and later scholastic philosophers' works are properly understandable, and therefore it is precisely our general lack of this conceptual background that renders works like his "De Hebdomadibus" so cryptic to the modern reader. Let me, therefore, try to sketch here at least some of the essential points of this background, on the basis of which perhaps we shall gain some insight into the main points of this grand system of thought. So let us see first what are in particular the points we are generally missing from the background of Boethius's question, what is it that renders this very question so enigmatic to the modern reader?

I think that besides the unfamiliar technical terminology, which, after all, one can easily acquire, the main reason that the modern reader may find Boethius's very question unpalatable is that it rests on certain assumptions we are no longer prepared to accept. Evidently, asking how it is possible that substances, that is, self-subsistent beings are good in that they are, although they are not substantially good, presupposes that every substance is good, which is to say that there are no bad substances. But, of course, for example, human beings are substances, i.e., self-subsistent beings, and, unfortunately, there are bad people. So some substances are evidently not good. Then why should we swallow such a presupposition, when it appears to be evidently false?

As a matter of fact, if we take a closer look at what Boethius himself says about his own assumptions, which he takes to be self-evident, we can see that probably many of these assumptions were not generally regarded as self-evident by his contemporaries either. When he puts forward what he regards as the axiomatic assumptions required for a resolution of the question, explicitly taking the axiomatic method of mathematics as his model, Boethius makes an interesting distinction concerning the self-evidence of these assumptions. He says that self-evident assumptions, what he calls here common conceptions of the mind, generally fall in two classes.

Common conceptions of the one kind are approved by anyone as soon as they hear them uttered, while common conceptions of the other kind are approved only by the learned, although these latter conceptions are somehow derived from those of the first kind. Now, evidently, there are self-evident propositions of the first kind. Boethius's own example serves as a good illustration: "If from equals you take away equals, the remainders are equal". Anyone hearing and understanding this proposition immediately assents to it, so that its denial would be unacceptable to him. But this also means that anyone understanding this proposition would find any apparent contrary evidence easily dismissible. Indeed, we may say that one can be said to understand this proposition properly only if he is able to dismiss any apparently contrary evidence and point out how the proposition is irrefutable by that evidence.

Suppose, for example, that I have one gallon of water and one gallon of gasoline in two dishes in front of me. I take away half gallon of liquid from each dish. Then I measure the remainder and I find that I have half gallon of water, but less than half gallon of gasoline left. Did I thereby refute our axiom? Of course, the whole room reeks of gasoline, at least as much as this "refutation" reeks of incompetence. Evidently, anyone understanding our axiom will immediately point out that the phrase "you take away" is not to be construed strictly and literally, and that despite the fact that I took away equal amounts of liquid, due to the fast evaporation of gasoline, it was not equal amounts by which the original amounts decreased, and this is why the remainders are unequal, not because of the falsity of our axiom.

So far, so good. But what about the other class of self-evident propositions? What difference does it make in self-evidence whether a proposition is approved by the learned? Isn't Boethius just trying to appeal to the vanity of his reader here? Well, the matter is certainly more important than that, and, in any case, Boethius definitely does not want to be popular in this work, so there is no need for him to flatter his reader. On the other hand, as we could see in the previous example, recognizing the self-evidence of a proposition does have something to do with competence. Indeed, we can say that recognizing the self-evidence of this proposition takes only linguistic competence: anyone who understands this proposition properly immediately assents to it, and knows how to eliminate the apparent contrary evidence, as demonstrating not the falsity of the proposition, but the linguistic incompetence of the person who was trying to refute it.

Again, in the case of a simple mathematical proposition, such as "1+1=2", understanding this equation properly is all that is required for assenting to it. Therefore, anyone having the elementary arithmetic competence of possessing the concepts of natural numbers, addition and equality will immediately assent to this proposition upon hearing and understanding it. Again, the proper understanding of this proposition will involve the ability to dismiss apparently contrary evidence: anyone having this kind of elementary mathematical competence will be able to point out why adding one droplet of water to another one, yielding just one bigger droplet instead of two, will not falsify this arithmetical truth.

We can say, therefore, that while in the former case it was mere linguistic competence that was required to recognize the self-evidence of the proposition, in the case of a simple mathematical proposition it is some elementary mathematical competence that is required. So cannot we say that in the case of a metaphysical proposition, it is some sort of "metaphysical competence" that is required? But what is this "metaphysical competence", and what is its relation to those ordinary sorts of competence we all are familiar with? Indeed, finding an answer to this question may just serve to understand what Boethius meant by saying that common notions of the second kind are derived from those of the first kind.

In the previous simple cases of linguistic and elementary mathematical competence we could see that competence involved possessing the proper concepts expressed by our self-evident propositions in such a manner that would enable their possessor to explain how these propositions can be maintained against apparently contrary evidence. Now, perhaps, we can say that the same applies to even less elementary cases, i.e., to cases in which more abstruse concepts and more sophisticated means of eliminating apparently contrary evidence are involved. Consider for example somewhat more advanced mathematics, like non-Euclidean geometry. On the basis of understanding the logical independence of the axiom of parallels from the rest of the Euclidean axioms we can accept the idea of a consistent geometry in which some denial of this axiom serves as a first principle. Of course, understanding non-Euclidean geometries will require a more sophisticated understanding of the elementary notion of a straight line, for example. This understanding is achievable by reflecting on how the axioms regulate the formation of our elementary notions, and so how the consistency of non-Euclidean axiom-sets allows the formation of the concept of a non-Euclidean straight line. But once this understanding is achieved, again, on the basis of this understanding one can easily eliminate apparently contrary evidence, say, our inability to draw or even imagine more or less than one straight line parallel to a given line on a blackboard, which is perceived to be contrary only because of the lack of the required competence.

But then, we can say that the "metaphysical competence" we are looking for is again nothing but the possession of some more sophisticated concepts, formed on the basis of our more elementary concepts available just to anyone, but the formation of which requires further careful reflection on these elementary concepts. However, once we have these more sophisticated concepts we shall have such a proper understanding of the first metaphysical principles that will enable us to see how we can eliminate apparently contrary evidence, perceived as contrary only for want of this kind of competence.

Anyhow, let us take a fresh look at the claim presupposed by Boethius's question from this angle. Let us see how, on the basis of a proper understanding of the claim that every being is good we can eliminate the apparently contrary evidence of the existence of bad people. To see this, we should first consider on what basis one can hold that such a claim is irrefutable, what understanding of the concepts of being and goodness are required to hold such a claim against the evidence of the existence of bad people (let alone other evils).

Saint Thomas Aquinas, who wrote an extensive commentary on the De Hebdomadibus, in his Summa Theologiae [ST1 q.5.a.1.] addresses this problem in the following way:

"It appears that to be good is really different from just to be. For Boethius says in his De Hebdomadibus: "I observe that it is one thing that things are good and it is another that they are". Therefore, for things to be and for them to be good are really different.

In response to this question we have to say that to be good and to be are in fact the same, they only differ in their concepts. And this should be obvious from the following. The concept of being good consists in being desirable, wherefore the Philosopher in bk. 1. of the Ethics says that good is what everything desires. But it is evident that everything is desirable, insofar as it is perfect, for everything desires its own perfection. On the other hand, everything is perfect inasmuch as it is actual, whence it is obvious that everything is good inasmuch as it is, for being is the actuality of every thing [...]. Therefore, it is clear that to be and to be good are in fact the same, but the concept of good implies the concept of desirability, which is not so implied by the concept of being.

To the first objection, therefore, we have to say that although to be good and just to be are in fact the same, as they differ in their concepts, it is not in the same way that something is said to be good, and that something is said to be, without qualification. For since the concept of being implies that something is actual, and actuality is properly opposed to sheer potentiality, something is said to be, without qualification, on account of that by which it is primarily distinguished from something that is merely in potentiality. But this is the substantial being of each and every thing. Therefore it is on account of its substantial being that anything is said to be, without qualification. On the other hand, it is on account of further, superadded actualities that something is said to be somehow, as to be white means to be somehow, for to be white does not remove sheer potentiality, absolutely speaking, because it just qualifies something which already is in actuality [by its substantial being]. But being good implies perfection, which is desirable and therefore refers to what is an end. So that thing is said to be good without qualification which has its final perfection. But the thing that does not have the ultimate perfection that it should have (although it does have some perfection insofar as it actually is) is not said to be perfect without qualification, indeed, nor is it said to be good without qualification, but only with some qualification. So it is with respect to its first being, which is its substantial being, that something is said to be without qualification, but it is said to be good with qualification, i.e., insofar as it is a being [and thus it does have some primary perfection]; on the other hand, it is with respect to its ultimate actuality that something is said to be with qualification, but it is said to be good without qualification. Therefore, what Boethius said, namely that it is one thing for something to be, and it is another for it to be good, should be understood as concerning some thing's being and its being good absolutely speaking, without qualification. For by its first actuality [i.e., by its substantial being] something is a being, absolutely speaking, but a thing is good, absolutely speaking, by its ultimate actuality [i.e. by its ultimate, proper perfection]. On the other hand, the thing is good with qualification, with respect to its first actuality [i.e., insofar as it exists at all, thereby having some perfection, namely the actuality of being], while with respect to its ultimate perfection the thing is with qualification, [i.e., it is somehow, possessing also some further perfection, besides just actually existing]."

In order to solve our initial difficulty with the existence of bad people, there are two points in this passage that we should understand very clearly here. The first is the idea of real identity and conceptual difference of being and goodness, while the second is the resulting difference in their predication with and without qualification. To understand these points we have to consider first how and in what respects we call something a being.

Primarily, we call something a being in the sense that it is one of the actually existing things. In this sense a human being comes to be a being, when he or she comes to be, absolutely speaking, that is, when he or she is born. Again, this human being is a being as long as he or she lives, and ceases to be a being when he or she dies. It is being in this primary sense-which in the case of a living being is life-that St. Thomas calls substantial being. But besides just being in this primary sense, a being is or can be actual in several other respects. Once it is here, then it is there, once it is doing this, then it is doing that, etc. It is these further, superadded actualities that render a being, which already exists in the primary sense, i.e., which already has substantial being, to be somehow, that is, to have some further actualities, further determinate modes of existence. With respect to the primary, substantial being, something is called a being without any qualification. But with respect to these secondary, superadded actualities something is called a being only in some definite respect, being somehow (say, being here, being there, being this big, being of this color, being engaged in this activity, etc.).

We should notice here that something's being in the primary, absolute sense is compatible with the same thing's not being in some respect. For example, my being, absolutely speaking, that is, the fact that I am alive, is compatible with my not being now in Hungary, not going to the library and not meeting my friends there. On the other hand, given the fact that I'm a human being, which means that I'm a thinking, perceiving, living body, my being implies that I have to be somewhere, and I have to be doing something, compatible with my nature, such as giving a lecture at Yale. Indeed, being of this nature, my being here and doing this is incompatible with my being elsewhere and doing other things in those other places at the same time. So having this nature necessarily delimits the kinds of superadded actualities I can have at any given time. Therefore, my being without qualification, given the fact that I am of this limited nature, while implies several kinds of superadded actualities, not only permits but also implies several sorts of non-being in some respects. Obviously, as I am a body, my being, absolutely speaking, implies my being somewhere, but being a finite, delimited body, my being somewhere also implies my not being elsewhere. And the same goes for all other bodies. What is more, even if there were an infinite body, occupying all places in the world, whereby it could be said to be everywhere, even that body could not be said to be totally everywhere, for it is only some part of it that could be said to be here, while its other parts would be elsewhere. So even that infinite body would be delimited in its being, just like I am: being a body, that is, being extended in space, it could not be wholly everywhere, because being a body implies having parts located in different places. In fact, from this we can immediately see that if there is a being that has no such parts, and which, therefore, is not a body, but which still can be said to be somehow in a place, namely, by exerting its activity in this place, then such a being can be wholly everywhere, that is by exerting its activity fully in all places. It is in this way that we can say that God is totally everywhere, by exerting fully His creative power in maintaining the existence of everything, everywhere in this world.

Now having thus seen the implications and the limitations a given thing's nature imposes upon its secondary actualities, even if the thing has its primary, substantial being, we can easily understand how these various sorts of being are related to the thing's goodness, and so how a thing's being good insofar as it exists by its primary, substantial being is compatible with the thing's being bad, despite the identity of being and goodness in general. For, as Aquinas explained, just as the thing is called a being without qualification on account of its substantial existence, while it is called a being with qualification with respect to its secondary actualities, so is it called good without qualification with respect to its secondary actualities, while it is called good with qualification with respect to its substantial being. As we could see, the reason for this difference is not that being good is a different actuality from being in general, but that we can call something good on account of its perfection, which, absolutely speaking, involves also the secondary actualities of a thing required by its nature, while just to be, without qualification, although it is some perfection, does not imply the presence of the required secondary actualities.

Our bad person, therefore, is good, insofar as he is, that is, with respect to his substantial being, but he is not good, absolutely speaking, because he lacks the required secondary actualities, the kind of perfection a human being has to have to be called good without qualification, namely, the perfection of a human life, which is living a life according to what is best in us, that is, a virtuous, spiritual life.

So, on the basis of this more sophisticated understanding of the claim that every being insofar as a being is good, we can see how, despite appearances, the existence of bad people does not refute this claim. But, perhaps, even if now we see how we can maintain such a claim, we still cannot see why we should maintain it. Even if now we see how we can maintain the real identity of unqualified being with qualified goodness and of unqualified goodness with qualified being, we may still ask: why should we?

From the passage quoted from Aquinas we may gather the answer, if we consider again what we should understand by calling something good. As the Philosopher says: good is what everything desires. But the same idea is expressed by Boethius, saying that everything that is tends to some good. For we call good what is the end of action, for the sake of which something is done, whereby it is the cause of the causality of the agent, because the agent does not act, unless for the sake of the end, which is its good. But the natural object of all desire is perfection, which is the completion of the thing's being to the extent required and permitted by the thing's nature. So it is clear that it is always some being that is desired, and so it is being, insofar as it is the object of desire that is good. So we have to maintain that being, that is, to be, and goodness, that is, to be good, are the same, only the concept of good adds to the concept of being the aspect of desirability, whence any being is called good insofar as it is an object of some desire.

But, again, for a full understanding of this reasoning we have to see very clearly how we should interpret the further claims involved in it, namely, that every action tends toward some good, and that this good is perfection, whence it has to be some being. So we have to consider, again, the most plausible objections that can be raised against these claims.

First of all, it does not seem true that every action tends toward some good. For evidently, in the case of voluntary actions performed by intelligent agents, the agent, if not omniscient, can be mistaken about the effect of the action, and so although the agent is intending some good, the action will tend toward something bad.

Again, from experience we know that human agents often do and intend to do something bad. So they are not simply mistaken about the outcome of the action, but directly intend the bad effect, qua bad, what they wish to achieve by their action.

Furthermore, in the case of natural agents, not acting by free will and intelligence, it is not at all clear that the notion of acting for the sake of something good is applicable at all. For even if perhaps in the living world we can make some sense of what it is for a living being to act for its own good, whether or not it recognizes it as such, as a plant or an amoeba certainly does not, what would we say about the actions of a tornado, a volcano, or just the falling of a stone? How could these actions be regarded as tending toward some good?

Furthermore, what can we make of the idea that all these actions tend toward some perfection? For if we grant that all sorts of perfections are some form of being, either primary, substantial, or secondary, accidental being, how can we account for all sorts of destructive actions both in nature and in the sphere of voluntary actions?

Indeed, finally, how can we account for suicide, a manifest example of self-destruction depriving the agent of all perfection?

Now, again, in addressing these difficulties we must not forget that if we deny a principle, by the very act of denial we do not treat it as a first principle, since a first principle is something that if we properly and competently understand it, we cannot but assent to it, so by such a denial we just reveal our incompetence in understanding it. In the case of the principle that every action tends toward some good we know why we have to hold it, at least in the case of voluntary agents, for it is evident that an agent insofar as an agent will perform an action only for the sake of reaching some end, which, as such, is the good to be obtained by the action. We just don't know how to account for apparently contrary cases. So let's see these first.

The case of the mistaken agent seems really simple. The agent's action tends toward something which is bad, but which appears to the agent as good, so it seems that to accommodate such cases we only need to extend the interpretation of our principle to apparent goods. But there still are some problems with this simple solution. An apparent good is not some kind of good, it is simply not good at all, just like forged money is not a kind of money, but it is no money at all. So it seems that this extension of our interpretation of this principle is no more justified than the extension of the principle "you can legally buy goods for money" to forged money. So why should we accept this extended interpretation in this case?

The reason for this is that even if what the agent perceives as good is in fact not good, it will not move the agent to act, that is, it will not move as something good, unless the agent perceives it as something good. So the act evidently tends toward some perceived good, which is the end of the action precisely because, and only insofar as, it is some perceived good, regardless of whether it is in fact good or not. So insofar as this principle expresses the necessary relationship between agent, action and the end of action, it is evidently true, regardless of whether the end of action in itself is really or merely apparently good. So any agent insofar as an agent acts for the sake of something good, qua good, whether what it acts for is in fact good or merely apparently good. Consequently, it would be a mistake to modify our principle so that it will explicitly refer to some apparent good. For the agent is not moved by an apparent good as such, but by some perceived good as such. A hungry man may be misled by mock food, but he is deceived by mock food precisely because he did not desire mock food, as such, but real food, as such, which he perceives as good for him, insofar as he perceives it as capable of appeasing his hunger.

So the case of our principle and that of "you can legally buy goods for money" are not the same. For the principle: "every action tends toward some good", according to the right interpretation, i.e., taking "good" to refer precisely to that for the sake of which the agent is acting, is going to be true regardless of whether the end of action in itself is really good or not for the agent, that is, whether or not it is really going to confer some perfection on the agent, even if it is evidently for the sake of such a perfection that the agent desired it. On the other hand, the claim: "you can legally buy goods for money" will not be true regardless of whether we interpret it for real money or for forged money.

And by this we can also see the solution of the difficulty concerning evil intentions, when the agent is not mistaken, but seems to be acting for the sake of something bad. For in fact, even in these cases the agent acts only for the sake of some perceived good as such, which he or she intends to reach by some perceived bad. But also in this case the end of action is that for the sake of which it is done, which moves the agent as something desired, and so as some perceived good of the agent. This is most manifest in the case of bad actions committed for the sake of some perceived profit for the agent.

But what shall we say, then, of self-destructive actions, or of the ultimate self-destructive action, that is, suicide? What profit, what perceived good would the agent hope to gain, when knowingly deprives him- or herself of the very possibility of any good at all? Well, suicide is an act of desperation, an act of riddance of some greater evil. So when the agent suffers some ultimate deprivation of a natural good state, say, health, what is ultimately desired is that natural good state, which, however, at the same time is perceived as unattainable. So desiring that natural good state the agent terminates the insufferable unnatural state, by terminating his or her own existence altogether.

But all these considerations leave the cases of involuntary natural agents unaccounted for. Very briefly, two further points need to be considered here.

The first is the goal-directedness of the actions of instruments, as their action is being directed toward some end by the action of some voluntary agent. So even if a hammer may not be said to have a goal of itself, clearly, as the tool of a craftsman it does have a definite purpose and function in the operation of the craftsman, who directs its action toward some good perceived as such by him.

The second point is regarding all agents in the world as instrumental to God's intelligent voluntary action. Even without going into further details we can see that if God is an omnipotent, omniscient, benevolent agent, then all actions of all natural agents can be viewed as directed to their proper ends by God's continuous creating activity, maintaining their nature and through this their characteristic operations. That in this case the perceived or unperceived good of these particular instrumental agents will be their own good is clear from the consideration that God directs their operations, in accordance with their nature by necessity or by freedom, towards the greatest good, that is towards Himself, which consists in these agents' assimilating themselves to God as far as their nature permits, that is, in achieving the maximal perfection allowed to them by their nature and by their individual proper operations.

From this consideration we can also see why it is so that not every individual of any nature possesses this maximal perfection at any time. For given the limitations of any finite nature, the perfection of one is often the privation of the other. The perfection of the life of the wolf requires sometimes the privation of the life of the lamb. So this is why the natural desire of the wolf toward something good, the preservation of wolf-life, involves coincidentally the privation of lamb-life. And the same goes for all destructive actions in nature.

Again, we can also see from this how we should understand Boethius's other principle according to which everything tends to its like, from which he concludes that everything is good, given that everything tends to some good. For, apparently, when the hungry wolf desires the lamb, it does not desire its like, on the contrary, the hungry wolf would certainly desire anything but another hungry wolf. On the other hand, what the hungry wolf desires is the state of the sated wolf. So the lamb is desired by, and, therefore, is good for the wolf not insofar as a lamb (for, say, a rabbit would do as well), but only insofar as it is conducive to this particular form of self-perfection of the wolf, that is its being sated. So despite appearances to the contrary, the wolf's desire per se is directed towards its like, namely the sated wolf.

However, one can object to this interpretation by saying that the hungry wolf is dissimilar to the sated wolf precisely in respect of the per se object of its desire, namely, in respect of being sated, wherefore it is not true to say that everything desires its like per se, that is, insofar as it is desiring. On the contrary, it seems that what desires does not have that what it desires, so it is dissimilar to what it desires, precisely in respect of what it desires, of necessity. As Socrates says in the Symposium: "it's necessary that this be so: a thing that desires desires something of which it is in need; otherwise, if it were not in need, it would not desire it". [200a-b]

To this, first of all, we have to say that Socrates's maxim is valid only for cases of desire for taking, but not for cases of desire of giving, that is, giving not for the sake of getting something in exchange, but just for the sake of giving. Such is the parents' love towards their children, or God's love towards His creatures. Secondly, even if, in cases of desire for taking, what desires does not have that what it desires in particular, and in that respect it is dissimilar to what it desires, Boethius's axiom does not concern such particular desires. Such particular desires are always instrumental to the universal, overarching desire of the thing's total activity, the thing's being in its specific nature, in which something similar is desired, namely, the preservation of the thing's being and well-being. When the hungry wolf desires to be a sated wolf, and so in this particular respect it desires to be what it is not, this desire of a particular dissimilarity is instrumental to a universal desire of similarity. For feeling hunger is instrumental for the wolf to stay alive, which is shown by the fact that a wolf that does not feel hunger will not hunt and will die. So when a hungry wolf desires to be a sated wolf, then it is a living, healthy wolf that desires to be a living healthy wolf, so in this respect it desires its like. As Socrates also says in the Symposium: "This is what it is to love something which is not at hand, which the lover does not have: it is to desire the preservation of what he now has in time to come, so that it will have it then". [200d-e]

That Boethius's axiom is indeed to be taken in this sense is shown by his subsequent argument [ll. 62-68.], in which he argues that things that are good cannot be good by participation, that is, having goodness as their accidental feature. For here he argues that what are good by participation cannot be good in virtue of their own being, wherefore they are not good in that they are. But then, they do not tend to some good, which is their like, which was conceded in the first argument. So also in the first argument [ll. 57-60.], tending towards its like has to be understood as a thing's tendency towards its like in its substantial being, that is, as the thing's tendency towards self-preservation. Therefore it is in this sense that, despite appearances to the contrary, the hungry wolf's desire for a lamb, which is its desire to be a sated wolf, is its desire towards its like, in that by this desire it is in fact a living wolf that desires to be a living wolf, that is, by the very activity of its life, which is its substantial being, it tends towards the preservation of this substantial being. So by its being it tends towards its own good, which is nothing, but itself in continued being, which is therefore its like in being, and so we can say that the wolf is itself good in its being. But in regard of their substantial being all substances are alike, so what goes for the wolf in respect of its substantial being goes for all substances in the same respect. So all substances in respect of their substantial being, that is, in that they are, are good.

But then it appears that they are substantially good. For whatever belongs to a thing insofar as it is belongs to the thing necessarily as long as it is. But what belongs to the thing necessarily as long as it is, appears to belong to it substantially, just like rationality, which belongs necessarily to a human being as long as he or she is, belongs to him or her substantially, that is, in virtue of what he or she is.

However, it cannot be the case that goodness should belong just to any created substance in virtue of what it is, that is, substantially, despite the previous conclusion that everything is good insofar as it is. For being substantially good is being good in essence, which means to have goodness as the thing's essence. But it is only God, the First Good, who has His goodness as his essence, so if everything is good by its essence, then everything is God, which is nonsense. So creatures cannot be substantially good. But since everything that has some property has it either substantially or accidentally, that is, in Boethius's terminology, by participation, and creatures cannot be good substantially, nor by participation, it seems that they can in no way be good, which contradicts our painfully established conclusion that everything is good insofar as it exists.

Boethius provides a solution to this problem by the following thought-experiment. Suppose the impossible, namely, that creatures exist and they are good, without God keeping them in existence. But then, since for a creature to be and to be something, like to be colored, to be here, to be of this weight, height, etc. are different, then also for them to be and to be good would be different. For otherwise all their properties were identical with their substance, and so the goodness of a creature would be identical with its substance, and also its whiteness and its weight and its height, etc., and so also these, say, their height and weight would be identical, which is nonsense.

On the other hand, if they did not have these material properties, like height, weight, color, etc. which all imply spatio-temporality, and therefore, some limitation of being, but they had only goodness, which does not have such spatio-temporal implications, because also a spiritual being can be good, then they could have this goodness as their substance. But if they had only goodness, which were to be their substance, then there would be no distinction between them, and so there would not be many things but only one, and that one would not be a creature but rather the First Good itself, that is, God.

So, on the basis of these considerations the following answer can be given to the original question. Creatures are good in that they are, that is, in their being, because their substantial being, deriving from the First Good itself is good. If, per impossibile, they could exist without God's maintaining their existence, then their existence would not be their goodness, so then they would not be good in that they are. However, since they in fact exist, because they receive their existence from the First Good, their existence is good, so they are good in that they are. Still, creatures are not substantially good, that is, their goodness is not their substance. This is precisely why for them to be good absolutely speaking is not for them to be absolutely speaking, but for them to be absolutely speaking is for them to be good only with qualification, that is, insofar as they are, insofar as they receive their being from what is absolutely good in what it is, that is Goodness itself, which is God. For it is only the unlimited divine nature that IS, totally and absolutely, without limitation, in full actuality of infinite energy, which therefore is the totality of unlimited perfection, and so is good, without limitation or qualification, since for Him to be is to be good, to be eternally living, thinking, happy, caring, providing, just and anything we can think of without limitation of perfection, indeed, exceeding in perfection anything we can think of, given the limitations of our own thought. So it is God alone who is substantially good, and it is only He, for whom to be good in his being is to be good absolutely speaking, while for creatures to be good in their being is not for them to be good absolutely speaking, but only insofar as they share in divine goodness by their being.

But, then, why cannot we say that they are white, or of any other accidental quality, in that they are, or isn't their being white a form of their being, and therefore their share in divine perfection? Yes, their being white is their share in divine perfection, still we cannot say that this belongs to them in that they are. For to be white is not just to be, for to be white is accidental, while to be is essential even to what is actually white. But we can say that they are good in that they are because their being derives from the First Good, which is essentially good. On the other hand, we cannot say that they are white in that they are, even if they got their whiteness from God, for their being white does not derive from The First White, but from God, who is not white, as being white per se implies being colored, and therefore, being a body, and therefore having spatio-temporal limitations in being, which cannot apply to the absolute being, God.

But then why cannot we say that anything that is just is just in that it is? Certainly, justice does not have such implications of limitation of being as whiteness does. But justice does have something to do with action: we cannot call somebody just, who does not act justly. But for us to be, and to be active are not the same, as we are not always in full activity throughout our being. But God is. So for Him to be, to be active, to be good and to be just are the same, his infinite divine essence. On the other hand, for us to be is to be good with qualification, insofar as by our being we share in divine goodness. But for us to be just is not only to be, but to act justly, and so it is only by that activity that we shall have our share in divine justice.

So if we want to be godlike, which is to want to be happy, for happiness is the perfection of a complete life, and so it is the unlimited perfection of divine life which is complete happiness in an absolute sense, then we have "to strain every nerve"-as the Philosopher says in the tenth book of the Ethics-"to live in accordance with the best thing in us", that is, to live a life by which we can have as much share in divine happiness as much our nature in our present condition allows us to have, so that we can leave this life well-prepared for a higher form of existence.

But isn't this just the message of Plato? Again, isn't this the message of Christianity, too? Indeed, on a larger scale, isn't this the message of all spirituality amassed in the history of mankind in all cultures and in all ages? In the age of the fall of the Roman Empire, in a total turmoil of conflicting interests and clashing values Boethius was striving to find an expression of this common message, lest it be lost in the turmoil, to the detriment of all mankind. Perhaps, in this age of turmoil of conflicting interests and clashing values, shaking societies on a global scale, we should take Boethius's concerns seriously, and regard them as our own concerns too.

Saint Thomas Aquinas:
Commentary on Boethius's De Hebdomadibus

Lect. 2. nn. 20-35. (Marietti, 1954)

10. Diversum est esse et id quod est.

10. Existence [esse] is different from that which is [id quod est].

11. Ipsum enim nondum est; at vero id quod est, accepta essendi forma, est atque consistit.

11. For existence itself not yet is, but that which is, when it has taken on the form of existence [essendi forma] is and subsists.

12.Quod est participare aliquo potest, sed ipsum esse nullo modo aliquo participat. Fit enim participatio cum aliquid iam est. Est autem aliquid cum esse susceperit.

12. That which is [quod est] can participate in something, but existence itself in no way participates in anything. For participation comes about when something already is. And something is when it has received existence.

13. Id quod est habere aliquid, praeterquam quod ipsum est, potest; ipsum vero esse nihil aliud praeter se habet admixtum.

13. That which is can have something besides what itself is, but existence itself has nothing mixed with it besides itself.

14. Diversum est tamen esse aliquid in eo quod est et esse aliquid.

14. However, it is different [for a thing] to be something in that [it] is [esse aliquid in eo quod est] and to be something [esse aliquid].

15. Illic enim accidens, hic substantia significatur.

15. For the latter signifies accident, while the former [signifies] substance.

16.Omne quod est participat, eo quod est esse, ut sit; alio vero participat ut aliquid sit.

16. Everything that is participates in existence in order to be, and it participates in something else in order to be something.

17. Ac per hoc id quod est participat eo quod est esse, ut sit; est vero ut participare alio quolibet possit.

17. But hence, that which is participates in existence in order to be; and it is, in order to participate in something else.

18. Omni composito aliud est esse, aliud ipsum est.

18. In every composite [thing] existence is one thing, and [the composite thing] itself is another.

19.Omne simplex esse suum et id quod est unum habet (1).

19. Every simple thing has its existence and that which [it] is as one.

20.Omnis diversitas discors; similitudo vero appetenda est.

20. Every diversity repels, but similitude is desirable.

21. Et quod appetit aliud, tale ipsum naturaliter esse ostenditur quale est iliud ipsum quod appetit.

21. And what desires something else is shown to be naturally like that which it desires.

22. Sufficiunt igitur quae praemisimus; a prudente viro interprete rationis suis unumquodque aptabitur argumentis.

22. These preliminaries suffice; the careful reader of the reasoning will adapt each of them to its appropriate arguments.


20. [...] Sicut ante dictum est, illae propositiones sunt maxime notae quae utuntur terminis quos omnes intelligunt. Ea autem quae in omni intellectu cadunt, sunt maxime communia quae sunt: ens, unum et bonum. Et ideo ponit hic boetius primo quasdam conceptiones pertinentes ad ens. Secundo quasdam pertinentes ad unum, ex quo sumitur ratio simplicis et compositi, ibi, omni composito etc.. Tertio ponit quasdam conceptiones pertinentes ad bonum, ibi, omnis diversitas discors.

20. [...] As was said above, those propositions are known the most whose terms everybody understands. Now those that fall into every intellect are the most common [notions], which are [the notions of] being, one, and good. Therefore, Boethius here posits first some conceptions that belong to being. [10-17] Secondly, some [conceptions] that belong to [the notion of] one, from which the concepts [ratio] of simple and composite derive, here: 18. In every composite ... [18-19] Thirdly, he posits some conceptions that belong to [the notion of] good, here: 20. Every diversity repels ... [20-22]

21. Circa ens autem consideratur ipsum esse quasi quiddam commune et indeterminatum: quod quidem dupliciter determinatur; uno modo ex parte subiecti, quod esse habet; alio modo ex parte praedicati, utpote cum dicimus de homine, vel de quacumque alia re, non quidem quod sit simpliciter, sed quod sit aliquid, puta album vel nigrum. Primo ergo ponit conceptiones quae accipiuntur secundum comparationem esse ad id quod est. Secundo ponit conceptiones quae accipiuntur secundum comparationem eius quod est esse simpliciter, ad id quod est esse aliquid, ibi, diversum est tamen. Circa primum duo facit. Primo ponit differentiam eius quod est esse, ad id quod est. Secundo manifestat huiusmodi differentiam, ibi, ipsum enim esse nondum est.

21. In connection with being [ens] we consider existence itself [ipsum esse] as something common and indeterminate, which is determined in two ways. In one way it is determined by the subject that has existence; in the other way it is determined by the predicate, as when we say of a man or of any other thing, not that it is, absolutely, but that it is something, say, white or black. Therefore, first he posits conceptions concerning the relationship of existence [esse] to what is [id quod est]. [10-13] Secondly he posits conceptions concerning the relationship of that which is to be absolutely speaking [eius quod est esse simpliciter] to that which is to be something [eius quod est esse aliquid], here: 14. However, it is different ... [14-17] Concerning the first point he does two things. First, he posits the difference between existence [quod est esse] and what is [quod est]. Secondly, he clarifies this difference, here: 11. For existence itself not yet is ...

22. Dicit ergo primo, quod diversum est esse, et id quod est. Quae quidem diversitas non est hic referenda ad res, de quibus adhuc non loquitur, sed ad ipsas rationes seu intentiones. Aliud autem significamus per hoc quod dicimus esse, et aliud: per hoc quod dicimus id quod est; sicut et aliud significamus cum dicimus currere, et aliud per hoc quod dicitur currens. Nam currere et esse significantur in abstracto, sicut et albedo; sed quod est, idest ens et currens, significantur sicut in concreto, velut album.

22. So he says first that existence is different from that which is. But this difference is not to be understood here as one concerning things, about which he is not speaking as yet, but the concepts or intentions [of existence and of that which is] themselves. For we [intend to] signify one thing by saying 'existence' [esse], and another by saying 'that which is' [id quod est], just as we [intend to] signify one thing when we say 'running', and another when we say 'that which runs'. For running and existence are signified in an abstract manner, just as whiteness; but that which is, that is, being, and what runs, [are signified] in a concrete manner, just as [what is] white.

23. Deinde cum dicit, ipsum enim esse, manifestat praedictam diversitatem tribus modis: quorum primus est, quia ipsum esse non significatur sicut ipsum subiectum essendi, sicut nec currere significatur sicut subiectum cursus: unde, sicut non possumus dicere quod ipsum currere currat, ita non possumus dicere quod ipsum esse sit: sed sicut id ipsum quod est, significatur sicut subiectum essendi, sic id quod currit significatur sicut subiectum currendi: et ideo sicut possumus dicere de eo quod currit, sive de currente, quod currat, inquantum subiicitur cursui et participat ipsum; ita possumus dicere quod ens, sive id quod est, sit, inquantum participat actum essendi: et hoc est quod dicit: ipsum esse nondum est, quia non attribuitur sibi esse sicut subiecto essendi; sed id quod est, accepta essendi forma, scilicet suscipiendo ipsum actum essendi, est, atque consistit, idest in seipso subsistit. Non enim ens dicitur proprie et per se, nisi de substantia, cuius est subsistere. Accidentia enim non dicuntur entia quasi ipsa sint, sed inquantum eis subest aliquid, ut postea dicetur.

23. Next, when he says: 11. For existence itself ... , he clarifies the above-mentioned diversity in three ways. The first of which is that since existence itself is not signified as the subject of existence, just as [the act of] running is not signified as the subject of running, therefore, just as we cannot say that [the act of] running itself runs, so we cannot say that existence itself is. But just as that which is is signified as the subject of existence, so that which runs is signified as the subject of running. Therefore, just as we can say of that which runs, or the runner, that it runs, insofar as it is subjected to running, so we can say of being, or that which is, that it is, insofar as it participates in the act of existing [inquantum participat actum essendi]. And this is what he says, namely, that existence itself not yet is, for existence is not attributed to it as to the subject of the act of existence; but that which is, when it has taken on the form of existence [essendi forma], namely, by receiving the act of existing itself, is and subsists, that is, subsists in itself. For only a substance, to which subsisting belongs, is said to be properly and per se a being. For accidents are not said to be beings, as if they themselves existed, but insofar as something is subjected to them, as will be said below.

24 Secundam differentiam ponit ibi, quod est, participare, quae quidem differentia sumitur secundum rationem participationis. Est autem participare quasi partem capere; et ideo quando aliquid particulariter recipit id quod ad alterum pertinet, universaliter dicitur participare illud; sicut homo dicitur participare animal, quia non habet rationem animalis secundum totam communitatem; et eadem ratione socrates participat hominem; similiter etiam subiectum participat accidens, et materia formam, quia forma substantialis vel accidentalis, quae de sui ratione communis est, determinatur ad hoc vel ad illud subiectum; et similiter effectus dicitur participare suam causam, et praecipue quando non adaequat virtutem suae causae; puta, si dicamus quod aer participat lucem solis, quia non recipit eam in ea claritate qua est in sole. Praetermisso autem hoc tertio modo participandi, impossibile est quod secundum duos primos modos ipsum esse participet aliquid. Non enim potest participare aliquid per modum quo materia vel subiectum participat formam vel accidens: quia, ut dictum est, ipsum esse significatur ut quiddam abstractum. Similiter autem nec potest aliquid participare per modum quo particulare participat universale: sic enim etiam ea quae in abstracto dicuntur, participare aliquid possunt, sicut albedo colorem; sed ipsum esse est communissimum: unde ipsum quidem participatur in aliis, non autem participat aliquid aliud. Sed id quod est, sive ens, quamvis sit communissimum, tamen concretive dicitur; et ideo participat ipsum esse, non per modum quo magis commune participatur a minus communi, sed participat ipsum esse per modum quo concretum participat abstractum. Hoc est ergo quod dicit, quod id quod est, scilicet ens, participare aliquo potest; sed ipsum esse nullo modo participat aliquo: et hoc modo probat ex eo quod supra dictum est, scilicet quod ipsum esse nondum est. Manifestum est enim quod id quod [non] est, non potest aliquo participare: unde consequens est quod participatio conveniat alicui cum iam est. Sed ex hoc aliquid est quod suscipit ipsum esse, sicut dictum est. Unde relinquitur quod id quod est, aliquid possit participare; ipsum autem esse non possit aliquid participare.

24. He posits the second difference here: 12. That which is [quod est] can participate in something ... And this difference is derived from the notion of participation. For to participate [to partake] is [literally] to take [a] part [est autem participare quasi partem capere]. Therefore, when something takes partially that which belongs to something else universally, the former is said to participate in that [which belongs to the latter]. (1) For example, man is said to participate in [the nature of] animal, for man does not have animal nature in its total community [i.e., not the whole of animality belongs to humans, for some part of it belongs to horses, some to dogs, etc.]; and in the same way, Socrates participates in man [i.e., in human nature, in that not the whole of human nature is in Socrates, but only his humanity, by which he is an individual human]. (2) Similarly, the subject participates in its accident, and matter participates in form, for a substantial or an accidental form, which [considered] in itself is common, is determined to this or to that subject. (3) And similarly the effect is said to participate in its cause, and especially when it does not attain the perfection of the power of its cause; as when we say that the air participates in the light of the Sun, for it does not receive it with the clarity that it has in the Sun. However, omitting this third way of participation (3), it is impossible that existence itself participate in something in the first two ways [(1)-(2)]. For it cannot participate in something in the way matter participates in form or a subject participates in an accident, since, as was said, existence itself is signified as something abstract [whereas only what is signified as concrete, a subject, can participate in this way]. Similarly, it cannot participate in something in the way in which some particular participates in a universal, for although in this way even those that are predicated in an abstract manner can participate in something, as whiteness [participates in] color, but existence itself is the commonest, so others participate in it, and it does not participate in something else. But that which is, or being, although it is the commonest, nevertheless, it is predicated in a concrete manner; and so it participates existence itself, not in the way in which something less common participates in something more common, but in the way in which something concrete participates in something abstract. So this is what he says, i.e., that which is, namely, being, can participate in something, but existence itself in no way participates in anything. And now he proves this from what has been said above, namely, that existence itself not yet is. For it is clear that what is [not] cannot participate in something, whence it follows that participation belongs only to what already is. But something is because it receives existence itself, as was said. So it remains that what is can participate in something, but existence itself cannot participate in something.

25. Tertiam differentiam ponit ibi, id quod est, habere et sumitur ista differentia per admixtionem alicuius extranei. Circa quod considerandum est, quod circa quodcumque abstracte consideratum, hoc habet veritatem quod non habet in se aliquid extraneum, quod scilicet sit praeter essentiam suam, sicut humanitas, et albedo, et quaecumque hoc modo dicuntur. Cuius ratio est, quia humanitas significatur ut quo aliquid est homo, et albedo quo aliquid est album. Non est autem aliquid homo, formaliter loquendo, nisi per id quod ad rationem hominis pertinet; et similiter non est aliquid album formaliter, nisi per id quod pertinet ad rationem albi; et ideo huiusmodi abstracta nihil alienum in se habere possunt. Aliter autem se habet in his quae significantur in concreto. Nam homo significatur ut qui habet humanitatem, et album ut quod habet albedinem. Ex hoc autem quod homo habet humanitatem vel albedinem, non prohibetur habere aliquid aliud, quod non pertinet ad rationem horum, nisi solum quod est oppositum his: et ideo homo et album possunt aliquid aliud habere quam humanitatem vel albedinem. Et haec est ratio quare albedo vel humanitas significantur per modum partis, et non praedicantur de concretis, sicut nec sua pars de suo toto. Quia igitur, sicut dictum est, ipsum esse significatur ut abstractum, id quod est ut concretum; consequens est verum esse quod hic dicitur, quod id quod est, potest aliquid habere, praeterquam quod ipsum est, scilicet praeter suam essentiam; sed ipsum esse nihil habet admixtum praeter suam essentiam.

25. He posits the third difference here: 13. That which is can have something ... And this difference is taken from the admixture of something extraneous. In connection with this [point] we have to consider that it is true for anything considered in an abstract manner that it does not have in itself anything external to it, namely, that is outside of its essence, like humanity, whiteness, and whatever else is predicated in this way. And the reason for this is that humanity is signified as that by which something is a man, and whiteness, as that by which something is white. But something is a man only by what belongs to the nature of man, and similarly, something is formally white only by what belongs to the nature of white, and so abstracts of this kind cannot contain in themselves anything alien to them. The case is different, however, with those that are signified in a concrete manner. For man is signified as that which has humanity, and white as that which has whiteness. But that a man has humanity or whiteness does not prevent him from having also something else that does not belong to the nature of these, except what is contrary to these. Therefore, a man and a white thing can have something else besides humanity and whiteness. And this is the reason why whiteness or humanity are signified as parts, and are not predicated of their concrete forms, just as no [integral] part is predicated of its whole. Since, therefore, as has been said, existence is signified in an abstract manner, and that which is [is signified] in a concrete manner, it follows that it is true what is said here, namely, that what is can have something besides what it is, that is, besides its own essence; but existence itself has nothing mixed with it besides its own essence.

26. Deinde cum dicit, diversum tamen est esse, ponit conceptiones quae accipiuntur secundum comparationem eius quod est esse simpliciter, ad id quod est esse aliquid. Et primo ponit utriusque diversitatem; secundo assignat differentias, ibi, illic enim accidens.

26. Next, when he says that 14. it is different [for a thing] to be ... , he posits the conceptions concerning that which is to be absolutely speaking [quod est esse simpliciter] and that which is to be something [quod est esse aliquid]. And first he posits their diversity, and then he assigns their differences, here: 15. For the latter signifies accident, while the former substance.

27. Circa primum considerandum est, quod ex quo id quod est, potest aliquid habere praeter suam essentiam, necesse est quod in eo consideretur duplex esse. Quia enim forma est principium essendi, necesse est quod secundum quamlibet formam habitam, habens aliqualiter esse dicatur. Si ergo forma illa non sit praeter essentiam habentis, sed constituat eius essentiam, ex eo quod habet talem formam, dicetur habens esse simpliciter, sicut homo ex hoc quod habet animam rationalem. Si vero sit talis forma quae sit extranea ab essentia habentis eam, secundum illam formam non dicetur esse simpliciter, sed esse aliquid: sicut secundum albedinem homo dicitur esse albus: et hoc est quod dicit, quod diversum est esse aliquid, quod non est esse simpliciter, et quod aliquid sit in eo quod est, quod est proprium esse subiecti.

27. Concerning the first point we have to consider that since that which is can have something else besides its essence, it is necessary to consider in it two sorts of existence. For, since form is the principle of existing, it is necessary that what has some form is said to be somehow in respect of any of the forms it has. So if the form is not outside of the essence of that which has it, but constitutes its essence, then the thing is said to be absolutely speaking, on account of having this form, just as a man [is said to be absolutely speaking] on account of having a rational soul. But if the form is such that it is external to the essence of the thing having it, then the thing is not said to be absolutely speaking, but [it is said] to be something, as in respect of whiteness a man is said to be white. And this is what he says, namely, that it is different [for something] to be something, which is not to be, absolutely speaking, and for something to be [something] in that it is, which is the proper existence of the subject.

28. Deinde cum dicit, illic enim accidens, ponit tres differentias inter praemissa: quarum prima est quod illic, idest ubi dicitur de re quod sit aliquid, et non sit simpliciter, significatur accidens, quia forma quae facit huiusmodi esse, est praeter essentiam rei; hic autem cum dicitur esse aliquid in eo quod est significatur substantia, quia scilicet forma faciens esse constituit essentiam rei.

28. Then, when he says: 15. For the latter signifies accident, while the former substance, he posits three differences between the above. The first difference is that by the latter, i.e., whereby it is said of the thing that it is something (and not that it is, absolutely), an accident is signified, for the form that makes this kind of existence is outside of the essence of the thing; but when something is said to be something in that it is, thereby substance is signified, namely, because the form that makes [the thing] be [absolutely] constitutes the essence of the thing.

29. Secundam differentiam ponit ibi, omne quod est, participat, ubi dicit, quod ad hoc quod aliquid sit simpliciter subiectum, participat ipsum esse; sed ad hoc quod sit aliquid, oportet quod participet alio aliquo; sicut homo ad hoc quod sit albus, participat non solum esse substantiale, sed etiam albedinem.

29. He posits the second difference here: 16. Everything that is participates ... , where he says that in order that something should be a subject absolutely speaking, it participates in existence itself; but in order that it should be something, it has to participate in something else. Just as a man in order to be white participates not only in substantial existence, but also in whiteness.

30. Tertiam differentiam ponit, ibi, ac per hoc, quae quidem accipitur secundum ordinem utriusque, et concluditur ex praemissis. Est autem haec differentia quod primo oportet ut intelligatur aliquid esse simpliciter, et postea quod sit aliquid; et hoc patet ex praemissis. Nam aliquid est simpliciter per hoc quod participat ipsum esse; sed quando iam est, scilicet per participationem ipsius esse, restat ut participet quocumque alio, ad hoc scilicet quod sit aliquid.

30. He posits the third difference here: 17. But hence, that which is participates in existence in order to be; and it exists in order to participate in something else. This difference concerns the relationship of the previous two and is inferred from them. This difference is that something first has to be understood to be absolutely speaking, and only afterwards to be something; and this is clear from what was said above. For something is, absolutely speaking, by participating in existence itself; but when it already is, namely, by participating in existence itself, it remains that it will participate in something else, namely, in order that it will be something.

31. Deinde cum dicit, omni composito, ponit conceptiones de composito et simplici, quae pertinent ad rationem unius. Est autem considerandum, quod ea quae supra dicta sunt de diversitate ipsius esse et eius quod est, est secundum ipsas intentiones; hic autem ostendit quomodo applicetur ad res. Et primo ostendit hoc in compositis. Secundo in simplicibus, ibi, omne simplex. Est ergo primo considerandum, quod sicut esse et quod est differunt in simplicibus secundum intentiones, ita in compositis differunt realiter: quod quidem manifestum est ex praemissis; dictum est enim supra, quod ipsum esse neque participat aliquid, ut eius ratio constituatur ex multis; neque habet aliquid extraneum admixtum, ut sit in eo compositio accidentis; et ideo ipsum esse non est compositum. Res ergo composita non est suum esse: et ideo dicit, quod in omni composito aliud est esse, et aliud ipsum compositum, quod est participatum ipsum esse.

31. Next, when he says: 18. In every composite [thing] existence is one thing, and [the composite] itself is another, Boethius posits conceptions concerning what is composite and what is simple, which belong to the notion of one. And we should consider here that what has been said so far about the diversity of existence and what is concerns their concepts themselves; here he shows how this is applied to the things. And first he shows this in connection with composite things. Secondly, in connection with simple things, here: 19. Every simple thing has its existence and that which [it] is as one. So we have to consider first that just as existence and what is are different in simple things in their concepts, so they are really different in the composite things. And this is clear from the previous considerations. For we have said above that existence itself does not participate in something, so that its nature would be composed of several things; nor does it have anything external mixed with it, so that there would be in it some composition of [subject and] accident; and so existence itself is not composite. Therefore, a composite thing is not its own existence. And this is why he says that in every composite thing existence is one thing and the composite thing, which participates in existence itself, is another.

32. Deinde cum dicit, omne simplex, ostendit qualiter se habet in simplicibus; in quibus est necesse quod ipsum esse et id quod est, sit unum et idem realiter. Si enim esset aliud realiter id quod est et ipsum esse, iam non esset simplex, sed compositum. Est tamen considerandum, quod cum simplex dicatur aliquid ex eo quod caret compositione, nihil prohibet aliquid esse secundum quid simplex, inquantum caret aliqua compositione, quod tamen non est omnino simplex. Unde ignis et aqua dicuntur simplicia corpora, inquantum carent compositione quae est ex contrariis, quae invenitur in mixtis; quorum tamen unumquodque est compositum tum ex partibus quantitatis, tum etiam ex forma et materia. Si ergo inveniantur aliquae formae non in materia, unaquaeque earum est quidem simplex quantum ad hoc quod caret materia, et per consequens quantitate, quae est dispositio materiae; quia tamen quaelibet forma est determinativa ipsius esse, nulla earum est ipsum esse, sed est habens esse. Puta, secundum opinionem platonis, ponamus formam immaterialem subsistere, quae sit idea et ratio hominum materialium, et aliam formam quae sit idea et ratio equorum: manifestum erit quod ipsa forma immaterialis subsistens, cum sit quiddam determinatum ad speciem, non est ipsum esse commune, sed participat illud: et nihil differt quantum ad hoc, si ponamus illas formas immateriales altioris gradus quam sint rationes horum sensibilium, ut aristoteles voluit: unaquaeque illarum, inquantum distinguitur ab alia, quaedam specialis forma est participans ipsum esse; et sic nulla earum erit vere simplex.

32. Next, when he says, 19. Every simple thing has its existence and that which [it] is as one, he shows how this is in simple things, in which it is necessary that existence itself and that which is are really one and the same thing. For if that which is and its existence were really different, then it would not be simple, but composite. But we have to consider that since something is called simple because it lacks composition, nothing prevents something from being simple in some respect, insofar as it lacks some composition, while not being totally simple. Whence fire and water are called simple bodies, insofar as they lack the composition from contraries, which is found in mixed bodies; but each of them is composed both of quantitative parts and even of matter and form. If, therefore, there are some forms which are not in matter, each of them is simple in that it lacks matter, and consequently quantity, which is the disposition of matter; but since every form is a determination of existence itself, none of them is existence itself, but something that has existence. For example, if in accordance with Plato's opinion we assume some immaterial form which is the idea and nature of material men to subsist, and another form which is the idea and nature of horses, it will be clear that the subsistent immaterial form itself, as it is something determined to a species, is not the common existence itself, but participates in it. And from this point of view it is irrelevant whether we take those immaterial forms to be of a higher rank than the natures of these sensible things, as Aristotle stated; for every one of them, insofar as it is distinct from the other, is some sort of specific form, participating in existence itself, and so none of them is going to be truly simple.

33. Id autem erit solum vere simplex, quod non participat esse, non quidem inhaerens, sed subsistens. Hoc autem non potest esse nisi unum; quia si ipsum esse nihil aliud habet admixtum praeter id quod est esse, ut dictum est impossibile est id quod est ipsum esse, multiplicari per aliquid diversificans: et quia nihil aliud praeter se habet admixtum, consequens est quod nullius accidentis sit susceptivum. Hoc autem simplex unum et sublime est ipse deus.

33. Only that is going to be truly simple which does not participate in existence, [which has] not inherent, but subsistent [existence]. And this can only be one. For if existence itself does not have anything mixed with it besides that which is existence, as was said, it is impossible for that which is existence itself to multiply by something diversifying: and since it does not have anything mixed with it besides itself, it follows that it is susceptible of no accidents. But this simple, one and sublime thing is God Himself.


As Aquinas' text presupposes a strong Aristotelian background, I will sketch here at least some essential points of this background, without which it is impossible to reach a correct understanding of Aquinas' metaphysics.

First of all, since Aquinas spends a great deal of discussion on how the essences of things are signified, we have to be clear about how he conceives of the relationships between our words, concepts and the things they represent. Crucial to his conception is what historians of mediaeval logic call the inherence theory of predication. This theory can be summed up very simply as follows:

A general term (i.e., a term that can be true of many things) signifies inherent forms of individual things. What makes such a term true of a particular thing is the actuality of the form signified by the term in this thing. If the form so signified is actual, then the term refers to this thing.

For example, the term 'round' is a general term, because it can be true of many things. This term signifies the inherent roundnesses of individual things, like the roundness of this or that particular billiard ball. It is the actuality of these roundnesses that makes these things round. Indeed, the term 'round' signifies also the roundness of, say, this particular lump of clay as well, but since this lump of clay is not round, its roundness is not actual. However, since it can be round, its roundness, signified by the term 'round', is potential.

So the term 'round' signifies all roundnesses of individual substances, whether these roundnesses are actual or not. This term, however, does not stand for these roundnesses. The term 'round' refers to a round thing, not to its roundness. Indeed it refers to the thing only if it is actually round, i.e., if the form signified by the term is actual in the thing.

Now this apparently very simple theory has tremendously far-reaching consequences in metaphysics. First of all, evidently, this theory is committed to a huge number of rather unusual, non-substantial and non-actual entities, such as Plato's past love towards Socrates, Homer's past blindness, or my presently merely potential, but in the future hopefully actual wisdom.

Well, Aristotle certainly did have a place for many of these things in his ontology: as we know, in his Categories he admitted without hesitation non-substantial entities falling in one of the nine accidental categories, and his theory of change and motion in his Physics actually requires several sorts of non-actual, past, future or merely potential entities. The above-sketched theory, however, is also committed to certain things that could not find their place even within this rather liberal ontological framework.

Privations, for example, being the lack of some positive entity, cannot be held to be either substantial or non-substantial entities falling directly in one of the ten categories. For example, blindness, being the lack of sight in an eye, is not so much an entity as a mere lack of an entity. Indeed, for blindness to exist is nothing, but for something else, namely for sight, not to exist. So the being of blindness is nothing but the non-being of sight, whence if sight is a being, blindness is a kind of non-being. But since nothing can be both a being and a non-being in the same sense, and blindness is a non-being in the same sense as sight is a being, blindness can be a kind of being only in a different sense.

Certain relative properties cannot be regarded as beings in the same sense either, as is clear if we consider their behavior in respect of change.

According to the Aristotelian analysis of change, a substance undergoes change, when a form that before the change was merely potential becomes actual in this substance. For example, the above-mentioned lump of clay in the hands of a potter may take on round shape, that is, its originally merely potential roundness will become actual, and so the lump of clay changes into a clay ball. So in this case, the actualization of a significate of a predicate, namely, of the predicate 'round' is a real change taking place in a substance. On the other hand, we cannot say that such an actualization is always a change of a substance.

Consider e.g. the situation, when the potter first decides that he will form this lump of clay into a ball. At that time something becomes true of this lump of clay that was not true of it before, namely that the potter thinks of it, as he wants to change its shape. But certainly the mere fact that the potter thinks of it, does not change the clay. So the actualization of this new property of the clay, namely that the potter thinks of it, is not a change in the clay. So here we have a case in which the actualization of a property of a substance, signified in this case by a relative predicate, is not a change of this substance. But then this property cannot be a being in the same sense as the ones whose actualization is a change of some substance.

Indeed, according to Aquinas, such are the relative properties of God in respect of His creatures. So the mere fact that by the change of His creatures God comes into different relations with the creatures does not imply any change in the immutable God.

Now it is for such and similar reasons that Aquinas begins his tract by distinguishing two different senses of the term 'being'. As he says, it is only beings in the first sense, that is, substances and their positive accidental properties falling in one of the nine accidental categories, that can be said to have real essences. Beings in the second sense are not real entities. They are just certain conceptual constructs of the human mind by which it conceives how real beings are.

To be sure, by saying that blindness or any other privation, say evil, is not a real being, Aquinas by no means implies that these privations do not exist, that they are mere figments, like centaurs or chimeras. What he says is only that they cannot be said to exist in the same sense as those positive entities of which these are the privations.

To see this in somewhat more detail, consider the following. Suppose we have to enumerate all the entities that there are in the world. Supposing, e.g., that actually we have three people in the world, Socrates, Plato and Homer, Socrates and Plato being sighted, while Homer being blind, we could begin counting like this: Socrates (1), Plato (2), Homer (3), Socrates' sight (4), Plato's sight (5), ... but at this point we could not go on: Homer's sight (6), for Homer, being blind, has no sight. On the other hand, we cannot go on counting either by saying: Homer's blindness (6), for Homer's blindness is not one of the entities in the world - by speaking about Homer's blindness all we mean is that there is a gap in this series of entities here: where there should be something by nature, there is a lack of this thing. But this lack, of course, is not on a par with the things that make up the world.

It is only things in the world, the real beings, that have their own natures, beings in the second sense are only insofar as by them our intellects conceive of the ways real beings are. So Aquinas dismisses from his considerations beings in the second sense, and considers only beings in the first sense, real beings, falling in one of the ten Aristotelian categories.

The beings in these categories are either substances, or their properties, inhering in substances as their subjects, namely accidents belonging in one of the nine remaining categories. Since it is substances that exist primarily, and accidents only as their dispositions, Aquinas devotes chapters 2-5. of his tract to considering the essences of various kinds of substances, and deals with the essences of accidents only in chapter 6. Chapters 2 and 3 deal with the essences of material substances, while chapter 4 deals with the essences of immaterial substances, that is, with the essences of angels and God. Chapter 5 provides a brief overview of the ways essence is found in different kinds of substances.

Now in order to understand these considerations, we have to be familiar with some basic concepts of Aristotelian logic, in particular, with the Aristotelian theory of definitions.

For Aristotle, a true essential definition of a certain kind of thing is not just the explication of the meaning of some term, referring to the things in question. A real definition signifies the essence of the things of this kind. Such a definition therefore enables us to formulate valid, scientific generalizations concerning the particular things of this kind, by which we can predict the ways they would behave under various possible circumstances.

A real definition consists of a genus, marking out a broader class of entities, thereby locating the kind of things in question in the system of the ten categories, and a specific difference, specifying more closely the kind in question, whereby we obtain a specific understanding of the species we wanted to define. By a series of such definitions we arrive at a clear and systematic understanding of various kinds of things, providing us with a general taxonomy of entities, which helps characterizing the specific subjects of particular branches of a unified Aristotelian science.

Such a series of definitions and the resulting ordination of general concepts according to their decreasing generality is what is usually referred to in Aristotelian logic as the "tree of Porphyry".

Now provided 'rational animal' is indeed a true essential definition of human beings, this definition signifies their essence: that in virtue of which they are what they are, namely humans. If we understand this correctly, we can immediately see how we should understand Aquinas's first main thesis of his tract, namely that the essence of material substances involves both their matter and their form.

As Aquinas explains, we should not understand this claim so that the essence of, say, Adam, is a third thing resulting from putting together two other things, namely his body and soul. ["Sed quia, ut dictum est, designatio speciei respectu generis est per formas, designatio autem individui respectu speciei est per materiam, ideo oportet ut nomen significans id unde natura generis sumitur cum praecisione formae determinatae perficientis speciem, significet partem materialem totius, sicut corpus est pars materialis hominis; nomen autem significans id unde sumitur natura speciei, cum praecisione materiae designatae, signifcat partem formalem; et ideo humanitas significatur ut forma quaedam, et dicitur quod est forma totius, non quidem quasi superaddita partibus essentialibus, sicut forma domus superadditur partibus integralibus eius; sed magis est forma quae est totum, scilicet formam complectens et materiam, cum praecisione tamen eorum, quibus nata est materia designari." c.3. in fine, p.24.]

Indeed, as he also explains later, Adam's humanity cannot contain his individual matter, since that is precisely what falls outside his essence, rendering him this particular individual, but not rendering him this kind of individual, namely a human being.

On the other hand, being the kind of individual he is, Adam has to have a body, indeed, has to be a body, namely a living, sensitive, rational body. But then, a body being nothing but a material substance, Adam's essence somehow has to involve matter. Well, if not his individual matter, then somehow matter in general. However, there is no such a thing as matter in general. So how can there be matter in general in the essence of a material substance?

To answer this question we should return for a while to the inherence theory of predication. As we could see, in this theory a general term signified individual, inherent properties of particular things. For such a term to be general, it is not required that it should signify some general thing. For generality it is enough, if particulars are signified in a general manner, i.e., disregarding their individual differences. For example, the term 'man' is equally applicable to all humans. But this is not so because it signifies some universal man, to which all the particular humans are somehow related, say, by participation, as Plato would have it. What this term signifies is the individual essences of this and that human being, but not signifying them as belonging to this or that. The signification of this term abstracts precisely from those features of this or that human that distinguish them from one another and applies to them only in virtue of what makes them both humans. But as we can see from the definition of man, a man, being a living, sensitive, rational body, is a material substance, so what is signified by this term, human essence, does involve matter. However, even if there is no other matter of a human being than the matter of this or that human being, it is not this or that matter, conceived as such, that is involved in the essence of man signified by this term. As Aquinas says, it is essential for a man to have flesh and bones, but it is not essential for a man, insofar as a man, to have, say, Socrates's, or any other particular man's flesh and bones. Indeed, if this were the case, someone could be human only by having Socrates's or that other particular human's flesh and bones, which is nonsense.

Now as from these considerations we can see, the distinction between designated and non-designated matter is not a distinction between two things, but rather a distinction between different ways of conceiving of the same thing: once determinately, together with its distinguishing features, once indeterminately, disregarding these distinguishing features. So when Aquinas says that it is non-designated matter, as opposed to designated matter, that is involved in the essence of material substances, this need not mean that there is some universal matter over and above the particular matters of individual substances waiting to go into their universal essences. Instead, all this means is that these individual matters conceived without what makes them individual are involved in the essences of these things, as these essences are signified in them by their substantial predicates.

Indeed, for Aquinas, all these substantial predicates signify the very same essence in an individual substance. For example, if we take a look again at the Porphyrean tree presented above, we can see that all the predicates listed in it are true of the individuals mentioned at the bottom. Now St. Thomas' claim is that it is the very same form in Eve that verifies of her the term 'human', the term 'animal', the term 'rational', the term 'sensitive' etc. up to the terms 'body' and 'substance'. The difference between these predicates is that they signify this form in Eve according to different concepts, by which we conceive of different aspects of this form, endowing its bearer, Eve, with different capacities, which she has in common with a narrower or broader class of other individuals.

The term 'rational', e.g., signifies in her this form insofar as it enables her to think, which she has in common with Adam, and so, though being different individuals, they are both essentially and equally humans. The term 'animal' signifies in her the same form, insofar as this form enables her to exercise animal functions such as sensing and moving, which she has in common not only with Adam, but with, say a donkey, or a dog, so all these individuals are equally and essentially animals.

To be sure, the fact that Eve's animality is also her rationality, need not mean that also a donkey's animality should be a rationality. A donkey's animality is a specifically different animality from Eve's animality, namely an asininity as opposed to a humanity.

Again, the same form in Eve enables her to grow, digest and reproduce, which she has in common not only with other animals, but, say, with plants as well, and generally with any living organism. Indeed, it is also this form that extends her matter in three dimensions in space, which is a common feature of all bodies, so it is the same substantial form that is signified in Eve by the term 'body', whereby Eve belongs in the same genus of substances not only with living, but also with non-living material creatures. Finally, it is the same form that makes Eve a subsistent being, who does not need a subject to inhere in, but is rather a subject of other, dependent beings, namely accidents, inhering in her. So on account of this form, Eve is a substance, as opposed to an accident, which can exist only as some disposition of some substance.

On the other hand it is not on account of this form that Eve is a being. For, as Thomas argues, Eve's existence is distinct from her essence. Indeed, it is precisely for this reason that even if Eve is a self-subsistent being, as her essence alone does not provide a sufficient reason for her existence, she evidently needs some external cause to maintain her existence. But, the argument goes on, if this external cause again is such that its essence is distinct from its existence, then its existence is no more explained from its essence, than Eve's from hers, so that cause again needs something else to maintain its existence. So unless in this series there is a cause whose essence is identical with its existence, and which, therefore, needs no further cause to maintain its existence, nothing would have a sufficient reason for its existence, whence nothing would exist.

This is how the famous thesis of the real distinction between essence and existence in the creatures provides the metaphysical basis of St. Thomas's proofs for the existence of God. Given the essential insufficiency of these creatures to subsist in themselves, there must be a God, who alone has a self-sufficient essence, His essence being nothing but the plenitude of existence. So only He can give existence to His creatures: without His ceaseless providence all creatures would simply fall into nothing.

Now this is how, for Aquinas, a careful study of the metaphysical constitution of creatures can lead to a certain recognition of their Creator, insofar as by such and similar reasonings we can know that He is, that He is the cause of all being, because His essence is his own being, whence He is eternal, perfect, immutable, good, omniscient and omnipotent.

But such reasons will never reveal for us what is beyond all natural recognition of human reason, namely the mysteries of faith, which we recognize only through revelation. So it is at this point where natural reason unaided by the illumination of faith and revelation reaches its limits, beyond which it cannot go relying on its rational principles alone. Therefore it is here that metaphysics should give way to theology, which seeks an understanding of revealed truths insofar as this is possible in this life at all, so as to prepare the soul for facing Truth in the life that comes after this. So it is at this point that the philosopher must shut up. Amen.


THE INHERENCE THEORY OF PREDICATION A general term (i.e., a term that can be true of many things) signifies inherent forms of individual things. What makes such a term true of a particular thing is the actuality (the actual inherence) of the form signified by the term in this thing.

THE TWO SENSES OF BEING Beings in the first sense are real beings, falling in one of the ten Aristotelian categories. Beings in the second sense are not real beings, they are just objects of thought by which the mind conceives of the ways real beings are, whence they are called beings of reason. Accordingly, only real beings have real essences, signified by real definitions. Beings of reason have only nominal definitions, specifying the meaning of the names signifying them.

REAL DISTINCTION VS. DISTINCTION OF REASON A real distinction distinguishes two (or more) non-identical real entities, such as this man and this donkey. A distinction of reason distinguishes between things as conceived in different ways, by different concepts. So really identical things may be distinct by reason, on account of the same thing's being conceived differently. The distinction between designated matter and non-designated matter is a distinction of reason.

THE THESIS OF THE UNITY OF SUBSTANTIAL FORMS All substantial predicates of the same substance are true of this substance in virtue of the same substantial form. The predicates signify the same form under different aspects, according to different concepts. So the distinction between the significates of substantial predicates of the same thing is just a distinction of reason, not a real distinction.

THE THESIS OF REAL DISTINCTION BETWEEN ESSENCE AND EXISTENCE IN THE CREATURES The essences of creatures, signified by their definitions, are really distinct from their existence, the actuality of their essence, signified in them by the term 'being' (in its first sense).


In this lecture, first I'm going to discuss the conceptual connections between Aristotelian essentialism and medieval Christian natural theology. From these general considerations I shall move on to a detailed discussion of St. Anselm's ontological argument, and then to a further discussion of the general philosophical lessons we can draw from St. Thomas Aquinas's rejection of this argument and his own approach to natural theology.

As we know, historically one of the key figures in establishing the conceptual connections between Aristotelian essentialism and Christian theology was Boethius. In fact, it would be interesting to show exactly how Boethius's work, along with the works of other patristic writers, especially St. Augustine, had transmitted and transformed some basic philosophical concepts of Aristotle's philosophy, well before Aristotle's original philosophical works, especially his Physics and Metaphysics, were recovered for the West in the 12th century. However, since this would be impossible to do in this lecture, instead of tracing the actual historical development of the relevant ideas, let me sketch here briefly why Aristotelian essentialism could be conceptually a suitable framework for the evolution of medieval natural theology, and so how it could contribute to the evolution of the medieval philosophical concept of God. Therefore, what I am going to provide here is not an actual "history of ideas", but rather a reconstruction of the logical connections between some historical, and historically sometimes quite distant ideas.

As we know from Aristotle's Physics and Metaphysics, the Aristotelian conception of causation is intimately connected with essentialism. For a cause is something that accounts for the being or so-being of something else. And, since for a thing to be somehow is for it to have some attributes, the question of what the cause of this or that phenomenon is boils down to the question of what accounts for a thing's having this or that attribute. But we know that some attributes belong to a thing on account of its essential principles, namely on account of its matter and substantial form. So the form and matter of a thing are causes, indeed, the essential, intrinsic causes of the thing's being the kind of thing it is and of its having its essential attributes. In fact, if having this or that attribute depends only on these intrinsic principles, then by giving an account of having this attribute in terms of the nature of the thing we reach a final explanation for the phenomenon in question. For example, if water is indeed what we believe it to be, namely a compound consisting of H2O molecules, and this accounts for the fact that the freezing point of water is 0 oC, then by giving an explanation of the fact that water freezes at 0 oC in terms of the molecular structure of water we have reached a final explanation, where no further question makes sense regarding why water has this attribute.

On the other hand, when it comes to accidental attributes, the situation is different. Since the presence of accidental attributes of a thing cannot be accounted for in terms of its essential principles alone - as this is precisely what renders them accidental -, in accounting for the presence of some accidental attribute of the thing we have to refer to something else. Now this something else is what we call the efficient cause, namely that which by some active principle inherent in it brings it about that the thing has the attribute we originally wanted to account for.

But this explanation, in terms of the action of the efficient cause, does not necessarily give us a final explanation. For if the efficient does not have the active principle by which it brings about its effect essentially, then the presence of this active principle in the efficient is itself in need of further explanation, again, in terms of the activity of yet another agent. And this need for a further explanation re-occurs every time, when we are unable to give an explanation for the presence of such an active principle in the agent in terms of the nature of the agent itself. So only then shall we arrive at a final explanation, when we are able to give an explanation of the presence of the active principle of an agent in terms of the nature, or essence of the agent. However, even so, when we do reach such a final explanation of the presence of some particular attribute in some thing, namely, with reference to the nature of the ultimate cause of the presence of this attribute, we have still not accounted for the very fact that this ultimate cause actually has this nature, namely, that it exists at all. So even this final explanation is final only relative to the presupposition of the existence of the nature of the cause. But then, if the existence of this nature is not accounted for by this nature itself, then, again, we have to look for some external cause that accounts for the existence of this nature. And so we shall reach an absolutely final explanation only if we reach a cause, the nature of which in itself accounts for the very existence of this nature, namely, the existence of which is its nature.

Now that things around us in the world do not have all their attributes essentially is most manifest from the fact that these things undergo change during their existence. For what changes acquires an attribute that it previously did not have. But then it is clear that this attribute is not an essential attribute of the thing, since the thing necessarily has all its essential attributes during all the time of its existence, from beginning to end. So the appearance of such an attribute by change calls for an explanation with reference to an external, efficient cause. And then, further, the explanation should not be with reference only to a cause whose active principle is accidental to it, but with reference to a cause that has this active principle in its nature. And if the nature of the cause so arrived at is still not self-sufficient, then, again, we have to look for something that by its activity accounts for the subsistence of this nature, and so on, until we arrive at something self-sufficient, whose nature in itself accounts for its existence, for its nature is its existence.

Now the cause in virtue of which another cause acts is what we call a superior cause, and the cause which acts in virtue of the superior cause, we call an inferior cause. But a superior cause is always a more general cause, exerting its activity in a more general respect, and therefore, accounting for the activity of a whole class of inferior causes. To use Aristotle's example, this man is the cause of the generation of this other man. But this man could not possibly cause life, if he himself were not alive. So what accounts for the generation of this man is not only the activity of his particular inferior cause, his father, actualizing another individual human nature, but also the general cause of life on this Earth, keeping both father and son alive. And this is why Aristotle says that "man is begotten by man and by the Sun as well". But if the superior cause that we arrive at in a particular series of causes is still not self-sufficient, then we must proceed again, to a further, even more superior, and more general cause. But in all kinds of causes the precondition of all activity is their very actuality, that is, their very being. On the other hand, being is the most universal aspect of all kinds of actuality. So the most universal cause is going to be that unique cause, which by its activity accounts for the being and activity of all others. So whichever possible particular effect we take, in considering the series of causes that produce this effect, we always arrive at the same ultimate cause, in virtue of which all these particular causes act, and produce their effects in actuality. And this is that ultimate cause whose actuality calls for no further explanation, for being the proper cause of all existence, that is, all kinds of actuality, its nature is nothing but its own existence, that is, actuality, in an absolute sense.

Now since the cause always has to be actual in respect of what it causes, and the first cause is the cause of everything that there is and will be or can be, this first cause has to be always actual in all possible respects. But then it has to be itself unchangeable, for having all possible kinds of actuality in itself, it cannot acquire by change some sort of actuality that it does not already have.

But of course it cannot have all these kinds of actuality in exactly the same way as they are found in its ultimate effects, in the way they are adequately conceived by us in these effects, for in this way they are limited to the determinate natures of these effects, whence in this way they are incompatible. On the other hand, the ultimate source of their actuality has in itself all these kinds of actuality together in a single, indivisible act, which is its very essence, which therefore comprises all these sorts of actuality. But of this essence we cannot have an adequate formal concept, as our adequate formal concepts derive precisely from those finite, divided sorts of actuality that we conceive in the objects of our perception. As a consequence, of this infinite actuality we can have only some approximate, analogical conception, which we can form by denying of it all limitations and imperfections that we find in its effects, from which our adequate concepts derive, and by attributing to it all perfections we can conceive of, as to the unique source of all these perfections, but at the same time knowing that its perfection exceeds all perfections we can conceive of.

So on the Aristotelian conception of causality, based upon the idea of accounting for some sort of actuality ultimately in terms of the nature of the thing bringing about this actuality, it is necessary to arrive at the idea of an Unmoved Mover, a Prime Cause, that being itself the plenitude of actuality is the source of all actuality, that is, all being. As such, therefore, the Prime Cause has to contain all perfections its effects have, but in a superior manner, united and undivided, untainted by the limitations and imperfections with which they can occur in the things of some limited nature. Therefore the Prime Cause is living, intelligent, good and free. Indeed, more living, than any living thing from which we acquire our concept of life, and more intelligent than anything from which we can acquire our concept of intelligence, has more freedom then any freedom we can think of, and better than any good we can conceive. But then its action is purposive, that is, whatever it causes, it causes to some end. But since the Prime Cause is good, this end must be something good, too. And since the Prime Cause is the Ultimate Good, being the only self-sufficient and omniperfect good, it must be this Ultimate End itself. So the Prime Cause is not only the first efficient, but also the ultimate final cause, which directs everything to itself, not by coercion and against their nature, but on the contrary, precisely by giving them their nature, by which they can share in its perfections, as much as they can, as much as their limited nature allows them to do so. But it is precisely such a Prime Cause and Ultimate End that all people call God.

In view of these considerations, no wonder that Aristotelian speculations about the Prime Mover, as the ultimate source of all actuality, being itself of infinite actuality, could serve even centuries later as a suitable framework for Christian, as well as Jewish and Muslim, theologians for their considerations concerning the existence and nature of God, insofar as these could be recognized by the use of natural reason alone, unaided by divine revelation. In fact, it was in such a context that even earlier, in the late antiquity, Aristotle was partly reconciled with Plato in the works of Neoplatonic philosophers, like Plotinus or Porphyry, and platonizing theologians, like St. Augustine, Pseudo-Dionysius Areopagites and Boethius, by positing Plato's ideas in the Divine Intelligence. Plato's ideas in this context got reinterpreted as the archetypes of the whole creation, by which, in a single, undivided, eternal glimpse God contemplates his own infinite existence in all those possible ways in which this infinite and complete existence is imitable by any possible finite nature, which will get actual by participating in the emanation of this infinite actuality.

So Aristotle's Prime Cause, interpreted in this Neoplatonic vein, could quite naturally harmonize with the religious idea of a loving, provident, omnipotent and just God, who lives an omniperfect, eternal life above all times. Evidently, in the light of the previous considerations, Boethius's definition of eternity in his Consolations: "the total, simultaneous, perfect possession of interminable life", as a description of the form of divine existence, can justly be regarded as providing just a further explication of the Aristotelian idea of the infinite actuality of the First Cause. On the other hand, of course, this does not mean that Aristotle had had exactly the same concept of deity as Boethius did. Nor does this mean that Boethius or later theologians were merely writing glosses on an original Aristotelian idea. As a matter of historical fact, Aristotle's own philosophical-theological arguments in the Physics and the Metaphysics did not have any serious, direct influence in the West until their re-discovery in the 12th century. What this means is only that the more general Aristotelian ideas of essentialism, causation, and the necessity of an all-actual first cause combined with Neoplatonic theological speculations provided such a suitable conceptual framework, with which the genuinely religious idea of deity could in principle quite harmoniously fit in. Indeed, it is precisely this "embedding" of the concept of deity into such a philosophical context that rendered it suitable for further rigorous speculation and further enrichment, just as we can see this in the works of Boethius and St. Augustine.

It was this highly enriched and refined theological-philosophical concept, that, coupled with the ingenuity of an original and gifted mind, gave rise to a new train of thought about the existence and nature of God, in Saint Anselm's Proslogion in the 11th century.

In particular, Anselm's argument trying to establish God's real existence on the basis of what we are supposed to think of when we hear His name - a later version of which was dubbed by Kant "the ontological argument" - has had a tremendous career.

Spelled out in more detail than in Anselm's own text, the argument can be stated as follows:

By the meaning of the term,

(1) God is that than which nothing greater can be thought of

But if you understand what I just said, then you have to think of that than which nothing greater can be thought of, and, since whatever is thought of is in the intellect, as its object, we have to concede that

(2) that than which nothing greater can be thought of is in the intellect

Now let's suppose that what is so thought of is only in the intellect, that is

(*) that than which nothing greater can be thought of is not in reality

But certainly whatever is in reality, i.e., what exists, is greater than anything that is only in the intellect, for of course what is in reality is greater in reality, that is, in being and actual perfection, than anything that is not in reality at all, i.e., that does not exist, so

(3) anything that can be thought to be in reality can be thought to be greater than anything that is in the intellect but is not in reality

And it cannot be doubted either that

(4) that than which nothing greater can be thought of can be thought to be in reality

So something can be thought to be in reality, which therefore can be thought to be greater than anything that is only in the intellect, and so, if that than which nothing greater can be thought of is only in the intellect, then

(5) Something can be thought to be greater than that than which nothing greater can be thought of

that is, something can be thought to be greater than which nothing can be thought to be greater, which is a contradiction. But then, since all the other premises are evidently true, we have to abandon our supposition (*) that God, that than which nothing greater can be thought of, is not in reality. So He has to exist in reality.

Evidently, this piece of reasoning cannot be torpedoed on the basis that it presupposes that there is something than which nothing greater can be thought of, as it only requires that something is thought of than which nothing greater can be thought of. But Anselm makes it clear that anyone who claims to understand the phrase "that than which nothing greater can be thought of" has to think of something than which nothing greater can be thought of, which, therefore, being thought of, is in the intellect, as its object. By the above argument we can see, however, that it cannot be only in the intellect, whence we concluded that it has to be in reality, too.

It seems, therefore, that all Anselm's proof requires is that modicum of rationality that is needed to understand a simple descriptive phrase, to reflect on what the description implies, and to conclude to these implications concerning the thought object one has in mind as a result of understanding the description.

Indeed, the next argument requires no more either. If you understand the phrase "something which cannot be thought not to exist", you have to think of something which cannot be thought not to exist. But what cannot be thought not to exist is certainly greater than anything that can be thought not to exist. So, if that than which nothing greater can be thought of were something that can be thought not to exist, then something greater than that than which nothing greater can be thought of could be thought of, which is impossible. So, that than which greater cannot be thought of cannot be thought not to exist.

But already Anselm himself, as well as later on Gaunilo, had to realize at once that such a simple proof is not necessarily "foolproof". For the recalcitrant Fool of the Psalms can immediately turn Anselm's second argument around, pointing out that Anselm's second conclusion denies the obvious, namely that God can be thought not to exist, as his (the Fool's) own example shows.

Anselm's retort, that the Fool's denial was possible in the first place only because he is truly a fool, thoughtlessly mumbling words he himself does not understand, leads us directly to the crux of the very possibility of a dialogue between the Saint and the Fool, or put in less biased terms, between the theist and the atheist. For, evidently, to avoid a complete breakdown of communication, some basic requirements of rationality should be met equally on both sides. So clarifying these basic requirements is in the best interest of both parties. Let us see, therefore, which are those basic requirements of rationality that the Fool seems to fail to meet.

Anselm claims that when the Fool said in his heart: "There is no God" he could do so only because he did not know correctly what he was speaking about (no matter whether aloud or just to himself), as he simply did not understand the word "God" properly. Thus far, the Fool is not guilty of irrationality, only of ignorance of the proper meaning of an expression. If I say "An isosceles has four sides", of course I am talking nonsense, but I may think that the word "isosceles" in English refers to squares, in which case what I mean by this sentence makes perfect sense, although what the sentence means is nonsense. If, however, someone tells me that the word "isosceles" in English refers to plane figures having just three sides, two of which are equal, the situation is different. If I claim to understand this explanation, I cannot stick any longer with my previous assertion and be not guilty of irrationality, as I assent to what I know to be impossible, which is at least a sure sign of irrationality.

But Anselm's charge is precisely that once the atheist is told what the word "God" means, the first argument shows him that he cannot assent to his original claim on pain of contradiction. So he cannot assent to it, except irrationally, and, therefore, if he insists on his denial, he deserves to be called a fool.

Consequently, in view of the validity of Anselm's reasoning, the only way the atheist can rationally maintain his position is by denying one of Anselm's premises. Of course, it would be foolish of him to challenge the theist's "meaning-postulates", since this would at once disqualify him as an intelligent interlocutor. So this leaves him with denying either that God can be thought to exist in reality, or that God, that than which nothing greater can be thought of, is even in the intellect.

Choosing the first alternative would amount to claiming that God's concept is contradictory. Establishing this claim might require from the atheist a specification of his concept of God, which may very well be contradictory, but can easily be dismissed by the theist as inadequate. In any case, in Anselm's argument the concept of God to be employed is adequately specified by the first premise, and the atheist would probably be hard pressed to show that the description "that than which nothing greater can be thought of" is self-contradictory.

At this point, however, the atheist may shift the burden of proof by saying that even if this description does not seem to contain any prima facie contradiction, it may well be contradictory. By way of analogy, he may bring up the description: "the greatest prime number", which, on the face of it, does not appear to be contradictory, so it seems to refer to the greatest prime number. But, as we know from Euclid, the assumption that there is a greatest prime number leads to contradiction, so the description cannot refer to anything.

In response, the theist first of all can point to the whole tradition of rational (as opposed to mystical) theology showing how apparent contradictions concerning God's nature are resolved. Second, he can say that a contradiction, if derivable at all, could be derived from this description only with the help of other assumptions, just as in the case of the greatest prime. But, unlike the case of the greatest prime, these auxiliary assumptions probably need not be accepted as true. Finally, concerning Anselm's argument one can also say that the premise attacked by the atheist does not even require that Anselm's description be free from such implied contradictions. For the premise requires only that one can think that God (under Anselm's description) exists, which one can do even with the greatest prime, until one actually realizes the implied contradiction. So the burden of proof presses the shoulders of the atheist again, if he wishes to challenge this premise. Therefore, he has to turn to the other premise anyway, asking whether he has to admit God as at least a possible object of thought.

In response to this question the atheist now may claim that the way Anselm wishes to force him to think of God will not make him admit that God is even in the intellect, at least, in his intellect, despite the fact that he understands very well what Anselm means by his description, which may not be contradictory after all. For understanding this description does not require him to believe that it applies to anything, so understanding this description will not make him think of anything that he thinks to be such that nothing greater than it can be thought of. So, since he denies that the description applies to any thought object he can think of, he just does not have such a thought object in his mind, while he perfectly understands what is meant by this description.

But here the theist swoops down: of course the atheist is just a fool! - indeed, a wicked fool, who, only because of his insistent denial, admits to be simply unable to think of the same thought object that I think of, that is, God. With this last move the atheist just revealed himself for the miserable fool he is, for just in order to maintain his untenable position, he simply gives up his otherwise natural human ability to think of God, that than which nothing greater can be thought of.

So it seems that the theist now may claim that, as a result of his denial, the atheist just rendered himself unable to think of an otherwise humanly thinkable thought object. By denying the existence of God, it seems that the atheist will never be able to think of the same God as the theist, whose conception of God logically implies the existence of God, as Anselm's proof shows.

At this point, however, we have to notice that the atheist may consistently maintain his position even despite the validity of Anselm's argument, and still claim that he is able to think of the same thought object as the theist, so the theist has no reason to doubt his mental abilities. In particular, the atheist can say that when Anselm thinks of that than which nothing greater can be thought of, Anselm does have a thought object in mind which Anselm thinks satisfies his description, along with all its implications. The atheist, however, can then think of the same thought object, as that of which Anselm thinks that it is that than which nothing greater can be thought of, but not think that this description in fact applies to it, whence he is not forced to conclude to whatever valid implications the description may have concerning that thought object.

So the atheist can claim that he perfectly understands Anselm's description, and still deny that he has in mind something of which he thinks satisfies Anselm's description. At the same time he can also point out that this does not prevent him from thinking of Anselm's thought object. So Anselm's proof will not convert the atheist, who does not share Anselm's belief that his description applies to something, though he understands that many people have this belief, and he is even able to identify the object of this belief, as that fiction, the God of the religious.

Thus, the atheist, when speaking about God, is constantly using the theist's beliefs to refer to God, but without ever sharing them. Accordingly, he will be willing to admit that whoever thinks of something as that than which nothing greater can be thought of also has to think that this thing exists in reality, and that it cannot even be thought not to exist in reality. Being a consistent atheist, however, he himself will think of nothing as that than which nothing greater can be thought of (whence that than which nothing greater can be thought of, as such, will not be in his mind). But he still will be able to think of what theists think of as that than which nothing greater can be thought of.

Now it seems that St. Thomas Aquinas was perfectly aware of this possibility to evade the force of Anselm's reasoning. As he wrote in his Summa contra Gentiles:

"... granted that by the name 'God' everyone understands that than which greater cannot be thought of, it does not follow that there is something than which greater cannot be thought of in the nature of things. For we have to posit the name and its interpretation in the same way. Now from the fact that what is indicated by the name 'God' is conceived by the mind, it does not follow that God exists, except in the intellect. Whence it is not necessary either that that than which greater cannot be thought of exists, except in the intellect. And from this it does not follow that there is something than which greater cannot be thought of in the nature of things. And so no inconsistency is involved in the position of those who think that God does not exist: for no inconsistency is involved in being able, for any given thing either in the intellect or in reality, to think something greater, except for those who concede that there is something than which a greater cannot be thought of in the nature of things."

In this passage Aquinas explicitly refers to the asymmetry in the positions of the theist and the atheist with respect to Anselm's argument. Those who think of God as that than which nothing greater can be thought of cannot think that He does not exist, save inconsistently. For those, however, who think that for any thought object a greater is thinkable, no inconsistency arises, when they think of what in their view is mistakenly believed by the theists to satisfy this description, which, in their view, exists only in the theists' intellect.

Anselm's argument, therefore, can be compelling only for those whose "universe" of thought objects already contains a thought object than which, they think, nothing greater is thinkable, and who are therefore already willing to think of something as that than which nothing greater can be thought of. This willingness, however, cannot be forced by Anselm's argument on anyone, whose "universe" of thought objects does not contain such a thought object. Such a person has to be persuaded first to be willing to think of something as that than which no greater is thinkable. But this cannot be achieved by simply telling him to think of what the description applies to, as he simply does not think the description applies to anything, although, of course, he believes that others think it applies to something.

As can be seen, what helps the atheist maintain the consistency of his position is his isolating the theist's thought objects from his own: when it comes to giving a consistent account of the world as he sees it, the beliefs concerning God are simply irrelevant to the atheist (except insofar as belief in God influences the thinking and behavior of religious people), as these beliefs do not concern his own thought objects, those that he himself is committed to. So to prove for the atheist that there is a God requires showing him that given the domain of thought objects he is already committed to, he is also committed to something that the theist can justifiably identify for him as God.

Now this seems to be precisely Aquinas' program of natural theology in the Summa Theologiae. Given our normal everyday commitment to objects of the empirical, physical world, Aquinas' proofs for God's existence intend to show us that by this commitment we are also committed to a Prime Mover, a First Cause, a First Necessary Being, etc., which, he says, are all what a theist would identify as God ("et hoc dicimus Deum"). Then he goes on to show us that God, to whom we are thus committed, is simple, perfect, good, infinite, ubiquitous, immutable, eternal and one. In this way the atheist is not allowed to keep God in isolation from his own beliefs. Indeed, throughout Aquinas' argumentation no single description is given which would presumably give the full meaning of the term 'God' for the atheist, in the possession of which he could claim to have a full grasp of the meaning of this term, and then use it to refer to what he thinks only the theist believes satisfies this term. Instead, the term is given a gradually growing content with every conclusion concerning the thing to which we are already committed under five different descriptions, in virtue of the existence proofs. So, no wonder that the two questions in the Summa Theologiae following these considerations are precisely Aquinas' systematic reflections on how we analogically "stretch" our mundane concepts to have a contentful concept of God, and how this concept enables us to speak about God.

Now the actual ways Aquinas builds on his readers' existing commitments are apparently all too closely tied up with certain particular features of the Aristotelian world view. So no wonder that with the demise of this world-view, also Aquinas's ways lost from their persuasive force.

On the other hand, whether or not anyone ever is going to be able to come up with an unshakable proof for God's existence, certainly no human being can neglect reflecting at least on the very idea of there being a God. But then, even if it should be impossible for us in this life to acquire a formally adequate concept of God, whether we believe or not, we definitely can, and have to, learn at least what and how we are supposed to think of when speaking about God. And our most reliable teachers in this matter will always be those great spirits of the past, to whom we owe it that we have this very concept, by which perhaps "now we see through a glass, darkly", but without which nobody can even hope to see "then, face to face".


Descartes's philosophy is usually regarded as opening a new chapter in the history of philosophy, namely, modern philosophy. Now what is it that renders Descartes particularly modern, as opposed to his immediate predecessors, or even to some of his contemporaries and successors? Well, certainly not his main conclusions, namely the existence of God and the real distinction of the body from the soul. But the same can be said about his arguments as well. The skeptical arguments of the first meditation, as was pointed out already by Hobbes, were common stock of Academic philosophy. The most powerful skeptical argument, the Demon argument, is based on medieval theological considerations concerning divine omnipotence, and was already anticipated by Nicole d'Autrecourt in the 14th century. The intuitive certainty of cogitation is an old Augustinian idea reinforced in the Scotist and Ockhamist schools, the proofs for the existence of God are modeled after those in general currency among Scholastic theologians and philosophers, and the proof of the real distinction between body and soul is quite the same as Aquinas's proof of the real distinction between essence and existence in the creatures.

In fact, Descartes himself does not even claim originality in this regard. As he wrote in the "Dedicatory letter to the Sorbonne": "... I think that when properly understood almost all the arguments that have been put forward on these issues by the great men have the force of demonstrations, and I am convinced that it is scarcely possible to provide any arguments which have not already been produced by someone else." (p. 4.)

What is the novelty, then, in Descartes's philosophy? Well, if it is not so much the arguments themselves, then it is rather the arrangement and the general intent of these arguments, inviting us to take an entirely new attitude towards what can be known by us.

Indeed, I should rather have said: "what can be known by ME", where this "ME" stands just for any of us. For the acquisition of knowledge is certainly not a collective effort for Descartes. Learning about the arguments of others, indeed, getting convinced by them, even through a genuine grasp and understanding of them, may be a good exercise of comprehension and memory, but has nothing to do with the acquisition of knowledge for Descartes. As in his Regulae he remarks, even if we learned by heart all the arguments of Plato and Aristotle, in this way "we would acquire knowledge not of a science, but of history". (AT. x. 367.)

To be sure, this remark has a much deeper significance in the context of Descartes's thought than the commonplace truth that we should think over everything for ourselves to deliver a sound judgment on anything. For Descartes this means building up everything in our intellectual edifice by ourselves, starting from scratch. It means a total break with all kinds of preconceived opinions, indeed, it means a total break with intellectual history, in general. Compare this with the way medieval philosophers and theologians treated Aristotle, the Philosopher, and you'll have an idea what makes Descartes's attitude new in this regard. To use the medieval simile recently re-popularized by Umberto Eco, if the medievals conceived of themselves as dwarfs sitting on the shoulders of giants, then Descartes is the first dwarf to pretend, at least for the sake of exercise, that he is not sitting on the shoulders of any giant.

In his Discourse on Method, Descartes describes in autobiographical detail how, having found no certainty in the sciences he was taught in school, he set out on a search for some firm foundation for knowledge:

"One of the first considerations that occurred to me was that there is very often less perfection in the works composed of several portions, and carried out by the hands of various masters, than in those on which one individual alone has worked. Thus we see that buildings planned and carried out by one architect alone are usually more beautiful and better proportioned than those which many have tried to put in order and improve, making use of old walls which were built with other ends in view. ... And similarly I thought that the sciences found in books - in those at least whose reasonings are only probable and have no demonstrations, composed as they are of the gradually accumulated opinions of many individuals - do not approach so near to the truth as the simple reasoning which a man of common sense can quite naturally carry out respecting the things which come immediately before him. ... It is true that we do not find that all the houses in a town are rased to the ground for the sole reason that the town is to be rebuilt in another fashion, with streets made more beautiful; but at the same time we see that many people cause their own houses to be knocked down in order to rebuild them, and that sometimes they are forced to do so where there is danger of the houses falling of themselves, and when the foundations are not secure. From such examples I argued to myself that there was no plausibility in the claim of any private individual to reform a state by altering everything, and by overturning it throughout, in order to set it right again. Nor is it likewise probable that the whole body of the Sciences, or the order of teaching established by the Schools, should be reformed. But as regards all the opinions which up to this time I had embraced, I thought I could not do better than endeavor once for all to sweep them completely away, so that they might be replaced, either by others, which were better, or by the same, when I had made them conform to the uniformity of a rational scheme." (part ii.)

So finding certain knowledge for Descartes is a completely individual enterprise, which has to start with the demolition of all opinions in which one finds "at least some reason for doubt". (p. 12.) So Descartes's First Meditation is devoted to a systematic investigation of those opinions which we generally hold to be certain and true, to see whether they are indeed as indubitable as we usually treat them or not.

In the course of this investigation we can observe a systematic progress of this methodical doubt.

At the first step in this progress, doubt attaches to opinions whose truth requires the obtaining of some perceptible state of affairs. If the perception is unclear, we cannot be sure whether what we perceive is indeed the state of affairs required for the truth of the opinion. However, if we manage somehow to clarify this perception, we are usually quite sure that what we perceive is indeed what justifies our opinion. For example, the proposition: "The red tower in front of me is round" may not be verifiable by someone seeing the tower from afar on the basis of his actual perception of the tower. But by moving closer he can clarify this perception, so that it will clearly identify for him the relevant state of affairs, namely, that the tower is in fact red and round, and not white and square, for example, which only seemed to be red and round from afar, in the light of sunset. Primary, or ordinary doubt, therefore, can normally be overcome by "taking a closer look", by putting the perceiver in a position in which the new perception itself clearly identifies for him the required state of affairs.

Secondary doubt erodes the confidence in the match between even such clear perceptions and the required states of affairs. A however clear perception of the object in front of me may not necessarily correspond to the required state of affairs: a clear red-round-tower-perception may not be a reliable indication that there is a red, round tower in front of me, because this clear perception may be as chimerical as anything produced by my imagination, as in a vivid dream. So even very clear and distinct sense-perceptions may not serve as unshakable grounds for certainty concerning this type of propositions.

On the other hand, since works of imagination are put together from simple veridical perceptions as their components, this type of doubt may leave the reliability of at least some perceptions intact, namely of those simple perceptions which serve as the material for any possible fiction of our imagination. But then these simple perceptions may do good service in the verification of at least some opinions, namely those whose truth requires the obtaining of a state of affairs that is identifiable on the basis of these simple perceptions alone.

For example, suppose my clear red-round-tower-perception is chimerical, because there are no such things as red towers, with some real color, but there are, say, only extended substances with no further real, perceptible qualities. Suppose that what we perceive as color is just the structure of the surface of things determining the way they reflect light. So it seems that the proposition "The tower in front of me is red" is, strictly speaking, false, for there is nothing like redness in any object at all, as there are only material objects with purely spatial, geometrical properties. Nevertheless, another opinion, say, "The cylindrical object having such and such a surface in front of me is round" may still be true and verified by my clear red-round-tower-perception. Indeed, with my sunglasses on I would see different colors, so I could not reliably verify my former proposition involving reference to a color. But the second proposition, involving reference to geometrical properties alone, could still be verifiable by me regardless of the unreliability of my perception of color.

Secondary doubt allows for the possibility of our being doomed by nature to "wear sunglasses", as it were, subtly misrepresenting reality, but still allowing us to make correct judgments about some aspects of it. The role of science, then, would be to take away these subtle distortions of ordinary experience, thereby establishing the pure truth of the matter. So, if we live in a "geometrical world" of extended substances with no other perceptible qualities, propositions of applied mathematics may be true, but other propositions, involving reference to other perceptible qualities, are strictly speaking false, though they may serve well some practical necessities of our "glasses-bound" human life.

Tertiary or metaphysical doubt deprives even such simple, geometrical perceptions of their reliability, by presenting them as possibly produced by God, not representing anything that they appear to represent. Thus, my clear red-round-tower-perception would not justify even the proposition: "The cylindrical object in front of me is round", there being nothing at all to verify even this opinion. So divine omnipotence may be invoked to shake the foundations even of applied mathematics. But even without the assumption of divine omnipotence, if there is only a logical possibility of having the very same clear perceptions, without their corresponding objects, as e.g. in a perfect "virtual reality" program, then we have sufficient reason to doubt the reliability of these perceptions too.

Still, even this type of doubt may not shake the foundations of pure mathematics, whose propositions do not require the obtaining of any, geometrical or otherwise, actual state of affairs. So, e.g. the proposition: "Any cylindrical object is round" may be true and certain, even if there is no physical world at all.

But, of course, this is not the end of the story. For even if these propositions require for their truth nothing but their being logically derivable from axioms, which themselves are true on the basis of the pure logical connections of the ideas making them up, by pure feebleness of nature I may always be wrong in my judgment about these logical connections, even if, perhaps, in principle I could correctly conceive of them. Hence the proposition: "Any cylindrical object is round" may be false, being in fact underivable from axioms of geometry, even if I may find the derivation correct, whenever I check it.

Furthermore, it may also be the case that even propositions of pure mathematics do in fact require something more for their truth, than just the by me in principle conceivable logical connections of mathematical ideas. Hence, the proposition: "Any cylindrical object is round" could be false, on account of the obtaining of some non-physical situation in which some cylindrical object is not round. To be sure, such a situation is absolutely inconceivable to me, given the logical connection of my ideas of cylindrical shape and roundness, but it is perhaps conceivable by a higher intelligence, such as God, who has more comprehensive concepts of all possible things, and for whom, therefore, several things may be possible which are by me inconceivable. So by Divine Omnipotence it may be quite possible that the properties conceived by my ideas of cylindrical shape and roundness could be separated in some weird, by me inconceivable reality, which does verify the negation of my mathematical proposition, namely, in which some cylindrical objects are not round.

That this is indeed a possibility that Descartes seriously entertained is made clear e.g. in a letter he wrote to Arnauld: "it does not seem to me that we should ever say it of anything that it cannot be done by God; for, since the whole nature of what is good and true depends on His omnipotence, I would not even dare to say that God cannot make a mountain without a valley, or that one plus two does not equal three; I only say that He gave me such a mind that I cannot conceive a mountain without a valley, or that the sum of one and two is not three, etc.; <I only say> that such and the like imply a contradiction in my conception". (Cronin, p.63.)

But then it should seem that simply nothing can be certain. For we can be certain of the truth of anything either by sense perception, or by clear reasoning, realizing the logical connections of our ideas. But we have found reason for doubt in all kinds of propositions, whether they could have been justified in the one, or in the other way.

Or is there something that could resist even such an extreme, metaphysical doubt? Well, if I'm being deceived by a however powerful deceiver, it is at least clear that I'm being deceived, that is, I think something to be true what is false. And even if I don't think it to be true, but I doubt it, I'm still certainly thinking, for doubting is just a kind of thinking. And if I'm thinking all the time, while I'm thrown in this whirl of doubts, I certainly am, I am existing, for thinking is a kind of existing. But then I just hit upon something so certain, so evident and so unshakable that its evidence alone guarantees its truth: for let me be deceived even by an omnipotent deceiver, this very fact that I am being deceived, guarantees the truth of what I now so clearly and distinctly perceive, namely that I exist. The point in the certainty of this claim is that it requires nothing external at all for its justification: neither an external physical world, including my own body, nor the obtaining of any kind of possibly non-physical objective state of affairs which could be perceived mistakenly by my intellect; for the truth of this claim is guaranteed by my simply being aware of it.

Well, so far so good. I have at least one truth whose certainty is such that I can have no reason to doubt it, for my very doubt verifies it. Indeed, I can know that it is true on the sole basis of clearly and distinctly perceiving it and what is required for its truth.

Now is there anything else of such unshakable certainty among my opinions? Well, the mathematical truths and generally all truths of reason had previously seemed to be precisely of the same clarity before I found some reason for doubt in them. For they also had seemed to be true and indubitable just on the basis of their clear and distinct perception. And the only reason for doubting them was the metaphysical possibility of there being an omnipotent deceiver, on whose will even these truths may have depended. So I have to make sure first about this omnipotent agent, namely, whether there is any, and if so, whether it can be a deceiver.

Now here we arrived at a crucial point in Descartes's reasoning. The only unshakable certainty so far is that of cogitation: I am in doubt, I am thinking, I am, I am a thinking thing, these all are propositions whose truth cannot be undermined even by metaphysical doubt, for the very act of metaphysical doubt at once verifies them all. But since this act is thinking, which always has to have some intrinsic object, for there cannot be thinking which is thinking of nothing, we also have to be able to know with certainty something about the objects of this act too.

To be sure, sometimes it may not be fully clear what is the object of an act of thought, since our thinking tends to wander about, but when we firmly fix our minds on a certain thought object, we can have as clear a perception of this object as clear is the fact that we think. Indeed, it is precisely the clear perception of the thought object that makes us aware of the fact that we are thinking at all.

"Now" - as in his Second Replies Descartes himself expounds this step in his reasoning - "some of these perceptions are so transparently clear and at the same time so simple that we cannot ever think of them without believing them to be true. The fact that I exist so long as I am thinking, or that what is done cannot be undone, are examples of truths in respect of which we manifestly possess this kind of certainty. For we cannot doubt them unless we think of them; but we cannot think of them, without at the same time believing they are true, as was supposed. Hence, we cannot doubt them without at the same time believing they are true; that is, we can never doubt them." (p. 105.)

So just like the very act of doubt verifies that I am thinking, so the very act of thinking of these simple truths, eliminates the possibility of doubting them. But, then, how was it possible to doubt them in the first place?

Again, as Descartes in his replies explains, doubt can attach to these simple truths only when we are not actually considering them. For when we actually clearly and distinctly perceive them, by this very perception we perceive their truth. On the other hand, when we just remember having considered them, but we do not actually consider them, we may think that at the time when we were considering them we were deceived by an omnipotent deceiver. So, again, even if we can be sure about them actually, when we are in fact considering them, we cannot be sure about them habitually unless we know that we were not deceived at any time when we were considering them.

Indeed, this is precisely the way Descartes presents his point already in the Third Meditation, when he says: "... whenever my preconceived belief in the supreme power of God comes to my mind, I cannot but admit that it would be easy for him, if he so desired, to bring it about that I go wrong even in those matters which I think I see utterly clearly with my mind's eye. Yet, when I turn to the things themselves which I think perceive very clearly, I am so convinced by them that I spontaneously declare: let whoever can do so deceive me, he will never bring it about that I am nothing, so long as I continue to think I am something; or make it true at some future time that I have never existed, since it is now true that I exist; or bring it about that two and three added together are more or less than five, or anything of this kind in which I see a manifest contradiction." (p. 25.)

So there can be no doubt in anything which I actually perceive to be such that its denial would involve a manifest contradiction, or as a couple of paragraphs later Descartes puts it: "Whatever is revealed to me by the natural light - for example that from the fact that I am doubting it follows that I exist, and so on - cannot in any way be open to doubt."

But in order to be able to have also habitual certainty of what I can be so sure of when I actually consider them, I have to give my actual consideration to the question whether God exists, and whether He can be a deceiver. As at the moment I know of nothing with certainty, except myself and my ideas, to do so, I have to consider my idea of God in comparison to all the other ideas I have.

Now these ideas insofar as they all are acts of my mind are certainly not different from one another, as they are equally just certain actual states, modes, or in Aristotelian terms, just actual accidents of my mind. They widely differ, however, in what they represent, or at least appear to represent to my mind. For even if there is nothing in actual reality corresponding to these different ideas, it is clear that they appear to represent different objects, and that these different objects would be different in their degree of perfection and reality, if they existed. This is what Descartes expresses by saying that some of these ideas contain more objective reality than others. So ideas have exactly the same degree of actual reality insofar as they are actual accidents of my mind. But they contain different degrees of objective reality, depending on what degree of actual reality their objects would have, if they actually existed, whether this is really the case or not. For example, my idea of a centaur has more objective reality than that of a stone, for if a centaur really existed, then, being a living thing, it would be more perfect than a lifeless stone, whatever the actual situation is, whether there really are centaurs and/or stones or not. Again, my idea of walking contains less objective reality than that of a man. For even if there are no men, and therefore no acts of walking either, a man, if he existed, would be more perfect than his act of walking, for the man could exist without this act, but not conversely.

Now it is certain that the idea of God contains the most objective reality of all of my ideas, as this is the idea which at least appears to represent something which, if it existed in reality, would have all possible perfections. But does this imply anything as to the actual reality of the object of this idea? Well, in itself nothing. But, according to Descartes "it is manifest by the natural light that there must be at least as much reality in the efficient and total cause as in the effect of that cause. ... And this is transparently true not only in the case of effects which possess what the philosophers call actual or formal reality, but also in the case of ideas, where one is considering only what they call objective reality." (p. 28.) But then I can be sure that this idea did not acquire its objective reality from me, for the degree of objective reality contained in my idea of God certainly infinitely exceeds the degree of actual reality I have, and so also the degree of the objective reality contained in my idea of myself. Indeed, it also infinitely exceeds the objective reality of any other of my ideas, as none of my other ideas appear to represent an infinitely perfect being, so it could not arise from the objects of any of these ideas either, whether there really are any such objects or not, which I still cannot know at this stage. It is also impossible that this idea came from nothing, as it is clear by the natural light that nothing comes from nothing. It remains, therefore, that this idea can derive only from its truly existing object, namely God. So, since I can be certain that I am, and that I have the idea of God, which I cannot have from elsewhere, but from the truly existing God, I can be as certain of God's existence as of my own. But it was the certainty of my own existence that resisted even metaphysical doubt, so now my certainty in God's existence can resist this metaphysical doubt too.

Indeed, since my idea of God is that of a most perfect being, who cannot have any imperfection, and since deceit involves malice, which is an imperfection, I can also know with equal certainty that God is not a deceiver. And so at once I regained habitual certainty in all truths of reason, that is, their clear and distinct actual perception guarantees their certainty for all later times. For now that I know that God is not a deceiver I can also know that what I clearly perceive is absolutely true. Not because God could not make it false, if He wanted, but because now I know that He does not want this, for to want this would be to want to deceive me, but God cannot be a deceiver.

In fact, this newly gained certainty also provides another proof for God's existence. For now we can be sure that what we can clearly and distinctly perceive, namely the denial of which involves manifest contradiction, is absolutely true. But to think that God does not exist involves manifest contradiction, as God has all perfections, and existence is a perfection. So now we can see with perfect clarity that God exists, and that, consequently, this is absolutely true.

Again, the same holds for all axioms and soundly proven theorems of pure mathematics. Now that I know that there is a God and all truths depend on Him, but I also know that He does not want to deceive me, no skeptical argument can shake my certainty concerning these truths.

I still don't know, however, whether there is anything besides God and myself. On the other hand, I have these very vivid ideas of corporeal things, which should come either from bodies which are really like these ideas, or from God, or from some other creature of His, including myself. But now that I know that God cannot be a deceiver I know that all my clear and distinct ideas should come from bodies which really are like these ideas.

To be sure, by this we did not eliminate all grounds for doubt, for we have plenty of ideas which we don't perceive so clearly and distinctly as those simple, mathematical ideas, which characterize bodies insofar as they have their corporeal nature. So, maybe those ideas do not represent some further, simple qualities that really inhere in bodies, but they should after all represent something, which, therefore, should be analyzed in terms of those simple, mathematical properties about which we can have certain knowledge.

So by the mathematization of natural science we can gain certain knowledge about the nature even of those qualities that are so elusively represented to us by their sensory ideas. Finally, as to simple illusions, they can always be easily detected by using not just one of our senses, but all of them, and not only our senses, but also the judgment of our intellect, which, as we now can see, rests on solid, unshakable grounds.

So, as we can see, in this Cartesian program for philosophy and science, the trustworthiness of mathematized science is based on unshakable metaphysical certainty, by the elimination of metaphysical doubt. To be sure, the need for the elimination of metaphysical doubt may arise only for someone, who raises metaphysical doubt at all. But the point is precisely that anyone who does not consider this type of doubt cannot even hope to have this type of firm grounding either.

On the other hand, the way Descartes reaches this firm grounding may still leave his readers in doubt concerning some points. Above all, the most significant intrinsic problem with Descartes's reasoning, noticed already by his earliest critics, seems to be what is usually referred to as the "Cartesian circle". For Descartes's crucial step in the elimination of metaphysical doubt, namely the first proof of God's existence, seems to be resting on a circular reasoning. For Descartes needed to prove God's existence and that He is not a deceiver in order to have a divine guarantee for the certainty of truths of reason. On the other hand, in the very proof he had to use such truths of reason, which, therefore, could not yet have this divine guarantee, and so, they couldn't have the certainty required for the proof.

We must not forget, however, Descartes's distinction between what I called actual and habitual certainty. According to Descartes's intentions, metaphysical doubt undermines only our habitual certainty in truths of reason, but not the certainty of their actual consideration. Consequently, it is only their habitual certainty that needs to be restored by the proof for the existence of God, which, however, rests on the actual certainty of their actual consideration in the proof.

Well, I think we can admit that as far as the doubt formulated in the Meditations goes, this distinction works well. On the other hand, from the quote from Descartes's letter we could see that he actually held a much stronger doctrine about the possible falsity of these so-called truths of reason. And this possible falsity may well serve as a reason for doubt even in the actual consideration of these truths, even if we actually cannot conceive how they could be false.

That even Descartes himself was quite at a loss on this point is shown by his rather desperate exclamation in his Second Replies: "What is it to us that someone may make out that the perception whose truth we are so firmly convinced of may appear false to God or to an angel, so that it is, absolutely speaking, false? Why should this alleged 'absolute falsity' bother us, since we neither believe in it nor have even the smallest suspicion of it?" (p. 104.)

As we can see, being unable to deny the possibility of their 'absolute falsity' on the basis of what he holds about these truths, Descartes proposes rather to ignore it, on the basis of the certainty of their actual consideration. But this will not do for the purposes of demonstration. For even if we have absolute certainty of the premises, if they can possibly be false (whether we can conceive of their falsity or not), the conclusion will only be equally certain, but may, nevertheless, be equally false, even if we cannot conceive of its falsity. Therefore, even if we could not conceive the falsity of the principle that the effect cannot contain more reality than the cause, it might well be false. And so, even if, having been convinced by Descartes's argument, we could not conceive that God does not exist, it might well be true, for all the certainty of Descartes's argument. So Descartes's position created also such a transcendental doubt - namely a doubt concerning truth and falsity transcending all our rational capabilities -, which just cannot be eliminated on the grounds of the certainty of individual cogitation alone.

Descartes in his zeal to find a reason for doubt in every opinion he had held before, and prompted by pious considerations concerning divine omnipotence, embraced a doctrine which could yield in the end only absolute subjective certainty, but not absolute truth.

To get rid of the confusing multitude of conflicting opinions one can learn in society, Descartes set out on a quest for self-reliant certainty, all alone, leaving the rest of the world and the rest of humanity behind. Of course, he couldn't leave behind himself, and what essentially belonged to him, his ideas. As a modest and serious thinker, he of course realized all the limitations of an individual human mind, and knew all too well how liable it is to error. So, he was more than willing to suppose that he could be in error even in things which appeared so manifestly true that their falsity was inconceivable to him.

However, what is inconceivable to an individual may very well be objectively possible. Whether I can conceive of a triangle whose three angles are not equal to two right angles is one thing. Whether such a triangle is possible is another. But this objective possibility depends on objective logical connections of concepts describing this possibility. And these connections, in turn, depend on what these concepts objectively are in those human minds that form them at all.

I, as an individual, can always be wrong about what these objective conceptual relations amount to, for I may just have failed to master these concepts in my mind yet. But we, as a community, are infallible at least about these concepts, for they are all formed by us, and there is nothing over and above their connections that founds the truths formed about them.

Of course, this need not and will not prevent any of us from forming new concepts, and make them public. But these new concepts will never overthrow the old truths about old concepts. They may rather show the limitations of our old concepts, more clearly delineating the realm of their applicability. The concept of a Euclidean triangle could make room for a new, generalized concept of a triangle, of which the Euclidean is only a specific case. This, nevertheless, does not invalidate the truths proven about the Euclidean triangle. On the other hand, what could in fact eliminate these truths would rather be the complete abandonment of the concept of a Euclidean triangle. If no human mind would have such a concept, there would be no truth characterizing the content of such a concept either.

Now something similar was to be the fate of at least some of Descartes's "eternal truths", most notably of those playing a crucial role in his proofs for God's existence. Even if Descartes thought that the certainty of their actual consideration could resist even omnipotent trickery, in a couple of hundred years they proved to yield to simple human negligence. For who would nowadays regard it as certain "by the natural light" that the effect cannot contain more reality than the cause? Who would compare different degrees of objective reality of our ideas? Who would see a manifest contradiction in the claim that God does not exist?

In view of these considerations we may say that Descartes is not so much the first modern, as the last scholastic philosopher. Indeed, the last scholastic, who is the first to leave the school, who is the first to trust in himself and in God alone in his quest for certainty. But Descartes's paradox is that he finally finds this certainty within himself only by means of concepts that were put there by the School he deserted. All principles he finds evident by "the natural light" are in fact principles that are evident by the lights of the School. The School, where these concepts had been worked out through centuries by generations of individual thinkers, but who all perceived themselves as members of a community precisely by sharing these concepts and principles.

However, once the School is totally deserted, its concepts and principles get neglected and finally completely abandoned. But then the certainty of Descartes's "natural light" concerning the existence of a benevolent God, whose graceful activity guarantees the match between ideas and what they appear to represent, is fatally undermined. And so, on Cartesian grounds, we are left with the unshakable subjective certainty of the cogitations of our ego alone, shut off from a perhaps inconceivable, perhaps non-existent, transcendent reality. But then, it is no wonder that despite Descartes's best intentions to the contrary, it is precisely this aspect of Cartesianism that proved to be the most enduring in our "brave, new world" of universal egoism.

From Descartes's quest for self-reliant certainty, there remained the certainty of self-reliance. If Descartes was the first dwarf to pretend that he was not sitting on the shoulders of a giant, then we, his truly modern posterity, are the dwarfs who don't need such a pretense anymore. We have already fallen off.


In this talk I am going to argue for the thesis that Hume's criticism of our ordinary idea of causation is only one in a whole series of episodes in the protracted story of the vanishing of substance from modern Western philosophy (well, in more than one sense of this phrase).

But first, let me briefly sum up exactly what Hume's criticism of this idea of causation consists in. Hume observes that all our causal reasonings depend on the general supposition of the uniformity of nature, that is to say, that like causes under like circumstances will always produce like effects. This principle itself, however, is indemonstrable, according to Hume.

It cannot be proven a priori, i.e., prior to experience, as all a priori demonstrations rely on the principle of contradiction, but the denial of the uniformity principle does not imply any contradiction whatsoever. For it does not imply a contradiction in any particular case to suppose that we have like causes under like circumstances, while they fail to produce their usual effect. We can have exactly the same type of events leading up to a point at which we would expect the usual effect to follow, but it is always conceivable that the usual effect will in fact not follow.

On the other hand, this principle cannot be proven a posteriori, that is, on the basis of past experience either, for all a posteriori demonstrations rely on the presupposition of this principle, so such a demonstration would be circular, and so it would prove nothing at all. Trying to prove that like causes will always produce like effects in the future on the basis that they have always done so in the past simply begs the question. For from past experience we cannot extrapolate to the future unless we suppose the conformity of the future with the past. But this is precisely to suppose that like causes under like circumstances will always produce like effects, for this is precisely what we mean by the conformity of the future with the past.

What is important to realize about Hume's reasoning in the first place is that it concerns the very foundations of our belief in the general uniformity of nature. So it does not concern the everyday experience that sometimes, indeed, quite frequently, we fail in our expectations based on some causal reasoning concerning some particular outcome of events. Indeed, when something like this happens, we immediately start looking for the cause of the failure of this expectation. So instead of giving up our belief in the general principle of the uniformity of nature, we rather immediately apply it to the actual situation in question.

For example, to take Hume's paradigm-case for causation, suppose we observe one billiard ball rolling towards another standing on the table. What we expect to happen is that when the rolling ball hits the other, the first stops and the other starts moving. Now what if contrary to our expectation we see that after the collision the standing ball stays firmly in its place, and the other just bounces back from it, as if hitting the wall? Instead of beginning to doubt that the laws of elastic collision are still in force regarding billiard balls, we start looking for the cause of the strange phenomenon; and if we finally find out that the steadfast billiard ball was nailed down to the table, then, with all confidence in the unshaken laws physics, we spring into action against the practical joker.

Of course, Hume does not doubt that this is what we would do. In fact, he claims to know why we would act like this. He claims that he has that general theory of human nature which explains why humans would generally act like this under the given circumstances. But he also claims that this behavior has nothing to do with the much-cherished rationality of mankind, for, in fact, as the previous argument shows, we have no rational basis for such actions. As he concludes: "'Tis not, therefore, reason, which is the guide of life, but custom. That alone determines the mind, in all instances, to suppose the future conformable to the past." (p. 652.)

Now is it really just blind custom that motivates us looking for further causes, when our expectations or predictions fail? Or is there some truly rational basis for looking for other causes, rather than just gazing at the miracle, and so also for having had those expectations and having made those predictions in the first place?

To see this, let us consider a somewhat less mundane, more experimental situation. Suppose we have two shiny metal balls, of equal size, hovering in zero-gravity in the cabin of a space station, one being at relative rest, while the other moving towards it. We observe that after the moving ball hits the other, the moving ball stops, and the other starts moving in accordance with the laws of elastic collision.

Then we repeat the experiment with two other shiny metal balls, looking exactly like the previous ones. What we observe now, however, is that instead of the moving ball knocking the other into motion, the two balls merge into one, and the new, big ball is moving along with about half the speed of the originally moving ball.

But this time we are not going to be surprised, because we know that while in the first experiment the two shiny metal balls were made of steel, in the second one, the exactly same looking shiny metal balls consisted of mercury, which we knew were liquid at the cabin temperature! In fact, on the basis of this further piece of knowledge, we expected to happen precisely what happened, for we knew that the two liquid metal balls were going to merge, instead of behaving like the other, solid balls. So here we simply knew something more about these objects, which otherwise looked exactly alike, and so it was not on the basis of the actually perceived collection of their sensible qualities that we had our different expectations in the two cases.

Now what is important to notice about this hypothetical experiment concerning Hume's reasoning is that on Hume's principles we were rationally unjustified in our expectations even in possession of this extra piece of knowledge. With the steel balls we could have experienced exactly the same what happened with the mercury balls and conversely. For Hume it should not imply any sort of contradiction to suppose that the steel balls, staying solid, springy steel all the time, could have merged in the same way as the mercury balls did, or that the mercury balls, staying liquid mercury all the time, could have collided elastically, just like the steel balls did.

But at this point, perhaps, we may start to feel a little bit uneasy about Hume's reasoning. How could it be possible that the solid steel balls could have acted like something else, like a liquid? Doesn't this run counter our very notion of what it is for something to be steel, and therefore some springy solid under the given circumstances? Isn't this supposition in conflict with our conception of the very nature, or substance of steel?

Hume's answer to this would be that of course we may have such uneasy feelings, but if we do mean something by the phrase "the substance of steel", then this uneasy feeling is due to our habits based on past experiences alone; or, if we claim something more to be the basis of this uneasiness, then we are simply victims of a philosophical mirage, and we are just using words that don't make any sense. For words make sense only insofar as they are signs of our ideas. But "we have ... no idea of substance, distinct from that of a collection of particular qualities, nor have we any other meaning when we either talk or reason concerning it" - says Hume. (p. 16.) So if we really mean something by the "substance of steel", then it cannot be more, nor less than the collection of sensible qualities of any object made of steel, in our particular case, the collection of sensible qualities of the steel ball.

Of course, the trick in my presentation of the hypothetical experiment was that first I gave only a restricted description of the sensible qualities of the objects of the experiment, "the shiny, metal balls", and I betrayed only later that we were supposed to know also something more about them than what we could immediately see in the experiment. But this extra information, namely that the first pair consisted of steel, while the other of mercury, implies only further sensible qualities associated with our past experiences of steel and mercury, on the basis of which we had the expectations that we usually have concerning objects made of steel and of mercury. But, again, those past experiences imply nothing concerning the possible outcome of any future experiment, and so, aside from our habituation by our past experiences with steel and mercury, nothing justified our expectations.

On the other hand, if we claim to mean something else by the "substance of steel", namely some hidden subject, or essence, which sustains and somehow determines all the sensible qualities of steel, but which is distinct from all these qualities, then we are simply talking nonsense. For our words make sense only if they are signs of our ideas, and all our ideas derive ultimately from sense impressions. But that hidden subject, being distinct from all sensible qualities must be something insensible, so it can have no corresponding sense impression, and so we can have no idea of it. Therefore, the words purporting to refer to such a thing are simply meaningless.

As we can see, since our ordinary idea of causation is tightly connected to our concept of some unchanging nature or substance of things, Hume's criticism of our ordinary idea of causation is heavily dependent on his criticism of the concept of substance. Of course, in this he follows closely in the footsteps of Berkeley, who was the first to launch the kind of criticism against the concept of material substance according to which it is just a philosophers' mirage, which we had better get rid of as soon as possible. In fact, it is very instructive to observe just how closely does Hume follow Berkeley in the critical part of the latter's philosophy, and how easily he parts company with him, when it comes to Berkeley's speculations concerning spiritual substance.

But, as we know, Berkeley's prime target was John Locke's material substance, that hidden, inaccessible entity lurking behind the sensible qualities it is supposed to support. The main objective of Berkeley's criticism was to show that by getting rid of this philosophical chimera we lose nothing, except for an opportunity for learned ignorance to abuse language against the rules of plain common sense.

In fact, both Berkeley and Hume appear to agree on this point, namely that our idea of substance should either be analyzable in terms of the plain commonsense language of perceptible qualities, or, if one claims that it is not so analyzable, then this person is committed to talking nonsense. Now let us take a closer look at the foundations of this claim on Berkeley's and Hume's part.

Both thinkers agree that the main source of the nonsense-talk of philosophers is that manufacture of philosophical chimeras, the Lockean doctrine of abstraction. But why is this so? What is the supposed relationship between Locke's doctrine of abstraction and his concept of material substance? After all, even according to Locke's conception, our abstract ideas of substances are just "gappy" collections of sensible qualities! So why do Hume and Berkeley think that by attacking Locke's doctrine of abstraction, and thereby the idea of this "gappy" collection of sensible qualities, they will hit that insensible substance too, which Locke believed accounted for our having the ideas of such collections of sensible qualities?

The logical link for Berkeley between abstraction and material substance is Locke's distinction between primary and secondary qualities. Primary qualities are extension, figure, motion, solidity and number, or, in short, the mathematically characterizable properties of bodies and their insensible parts. Secondary qualities are the rest of sensible qualities, like color, smell, sound, cold, warmth, etc. According to Locke, primary qualities are really inherent qualities of independently existing material substances, while secondary qualities are only in the mind, caused by the primary qualities of these substances.

By his criticism of abstraction, Berkeley wishes to establish that the separation of primary from secondary qualities, even in thought, involves the same absurdity as the separation of anything from itself. But then, since secondary qualities exist only in the mind, primary qualities cannot have a mind-independent existence apart from these either. And so, if the phrase "material substance" has any meaning at all, it can refer only to some concrete collection of both kinds of sensible qualities, but it cannot refer to some independently existing entity having only primary qualities, concludes Berkeley.

But it seems that even apart from the doctrine of abstract ideas, Berkeley and Hume had every right to reduce Locke's idea of material substance either to sheer nonsense, or to a collection of simple ideas of sensible qualities.

For if by "material substance" Locke means something beyond these ideas, which is supposed to be distinct from all its sensible qualities, then on his own empiricist grounds he has to admit that we can have no idea of such a thing. For on these empiricist grounds all our ideas derive from sense perception. But of this thing we cannot have any sense perception, as it is supposed to be distinct from all its sensible qualities. So we can have no idea of it. But then, since according to Locke, words have meaning only by being the signs of ideas, he also has to admit that according to this interpretation these words mean nothing.

Again, if by "material substance" Locke means a collection of really existing sensible primary qualities which cause a corresponding collection of ideas (of both primary and secondary qualities) in the mind, then, despite possible appearances to the contrary, this phrase makes no more sense either. For, since it is only the ideas of these qualities that we are aware of, we could know of these qualities only by inferring their existence from the ideas, by supposing their causal relationship. But the same effects may always be produced by different causes. So we can never know it for sure, whether the same ideas represent the same qualities. But then, on the basis of having some sensation we can never be sure of the actual presence of the truly corresponding real sensible quality. But then, since it is only the impressions or ideas of these alleged qualities that we are ever aware of, we can know nothing about these qualities, for the same impressions or ideas might be produced by any other kind of qualities, in fact, even not by qualities, but by anything else. So, properly speaking, we don't have any ideas even of these qualities, for in principle just any idea could belong to any quality, or, for that matter, to anything else. But then no idea is an idea of this or that quality, properly speaking, in the sense that the presence of this idea is always caused by the presence of the corresponding quality. Therefore we have no ideas even of these alleged sensible qualities, which are supposed to be distinct from their ideas. And so, any words purporting to refer to such qualities are meaningless, whence the phrase "material substance" is equally meaningless, if it is supposed to refer to such a putative collection of really existing sensible qualities.

Finally, if by "material substances" Locke means collections of impressions or ideas of sensible qualities, which qualities are not thought to be distinct from these impressions or ideas, then he is not speaking about the causes of these impressions or ideas, but about the impressions or ideas themselves, and this is the only way in which, according to Berkeley and Hume, these words can make any sense, if at all.

But to cap this all, even if, per impossibile, we could form some idea of material substance purely on the grounds that it is the cause of our sense-impressions, since this idea would rest on the notion of causality, it certainly could not serve as a foundation of this notion by which we could evade the force of Hume's reasoning. For having an idea of material substance as being the cause of our sense impressions would presuppose that we have an idea of cause. But this idea of cause should derive ultimately from sense-impressions. And we have already seen from Hume's argument that such ideas can never supply a sufficient justification for the principle of the uniformity of nature, and so we could never know whether having a sense impression is indeed in conjunction with the presence of a substance.

So, all in all, since Locke's idea of material substance either reduces to sheer nonsense on his own principles, or to the same idea that was implied in Hume's criticism of causation, or, at best, it might be founded on the very idea of causation which is already undermined by Hume's reasoning, it certainly cannot serve itself as a firmer foundation for this idea.

However, Descartes may still have a way out here. After all, one cannot help noticing the clearly Cartesian origin of the distinction between primary and secondary qualities: primary qualities are precisely those qualities, which, based on the Divine guarantee of metaphysical certainty, fall within the realm of metaphysically founded, mathematized Cartesian science. On the other hand, Descartes's philosophy is certainly not bound within the epistemological limits of empiricism, and so he may very well have a purely intellectual idea of substance, which is distinct from a sheer collection of sensible ideas. But then this idea need not even be derived from causality in sense-perception as in Locke's philosophy, and so it may possibly serve as an independent foundation for the idea of causation.

Well, indeed, Descartes does have such an idea, as his analysis of the example of the wax shows. Our idea of the substance of the wax is definitely not the collection of the sensible qualities of wax, for while all these sensible qualities may change, by this idea we conceive of the same substance, which preserves its identity during all these changes. But then, if we do have such an idea of substance, then it indeed should reflect some unchangeable nature of the thing existing independently of our perceptions, and which, therefore, can serve as the basis of unchangeable, objective causal laws.

Descartes's analysis, however, immediately gives rise to at least the following two questions: 1. What is it that this idea represents, if none of the sensible qualities of this or that particular substance? 2. What guarantees that there is anything corresponding to such an idea in reality?

To the first question the answer at first sight seems to be obvious: it is the nature of the wax that the idea of wax represents. Very well, but what is this nature of the wax? And it is at this point that we usually come to a halt. As Gassendi's objections show, it seems just absurd that the taking away of all sensible, accidental qualities would yield a greater knowledge of the thing, if, in fact, we have just no idea what remains at the end of this process.

The point of this type of criticism is to show that those who claim to have a purely intellectual knowledge of the nature of material substances are usually at a loss to say what this nature is supposed to consist in, over and above the sensible qualities of these substances. And we must not forget here that with Descartes we are already in an age when descriptions of such supposed natures, like "waxhood", say, are the common laughing stock of a new breed of intellectuals, who are united, if by nothing else, then at least by a shared scorn for scholastic explanations.

It is important to notice, however, that on scholastic Aristotelian grounds there is just nothing absurd in having such a purely intellectual concept of a material substance. Indeed, in this conceptual framework, it is precisely one of the distinguishing features of intellectual cognition, as opposed to sense-perception, that the intellect by abstraction is able to comprehend the essence of the thing, constituted by the thing's substantial form, which accounts for the thing's necessarily having certain properties, including its causal powers, as long as the thing exists. And this is so because the substantial concept formed in this process of abstraction in the mind is itself nothing but the same substantial form which informs the matter of the thing, but existing in the mind abstracted from this matter.

Now this last point has an important further consequence, which renders the Aristotelian scholastic answer to the question concerning the relationship between our intellectual concepts and their objects radically different from Descartes's. For our substantial concepts being just the substantial forms of things without their matter in our minds, these concepts are necessarily related to their objects: it is logically impossible, according to this view, that we have a substantial concept of say, donkeys, which is not a concept of real donkeys, i.e., of substances having the substantial form of donkeys. Indeed, since substantial concepts and substantial forms are connected by logical necessity, even divine omnipotence is incapable of producing such a substantial concept in a human mind which is not of objects informed by the corresponding substantial form, that is, which is not of objects that really are what the concept represents them to be, for this would involve a contradiction.

For on this view a substantial concept is the substantial form of its proper object in the mind without the matter of this object. Now suppose that the same concept may be in existence, while not being the concept of its proper object, but of something else, or of nothing at all. But then, it cannot be the substantial form of its proper object without the matter of this object. So, then the same entity, the same concept, is supposed both to be and not to be the substantial form of its proper object without its matter, which is a contradiction.

Therefore, since for scholastic Aristotelians mental representations are necessarily connected to their objects, there cannot be any doubt that if I have a substantial concept of a certain kind of object, then, when I experience that kind of object, the object I experience really is what I conceive it to be by this concept. For example, if I have the concept of body, and I experience a body, then when I conceive of it by my concept of body, then what I conceive of by this concept is really what it is represented to be by this concept, namely, a real body.

To be sure, this does not render me infallible. Suppose I happen to experience not a body, but only an illusion of a body, say, in virtual reality. Then, if I judge this illusion to be a body, my judgment is false. But the point is not whether my particular judgments may be false, but whether it is possible that my concept of a body may apply equally well to a real body and to a virtual reality illusion of it. However, the very fact that this judgment in this situation is false, shows that my concept of a body may not apply to something that is not really a body, despite the circumstance that on the basis of my actual perception of the phenomenon I may mistake it for a body.

But what if the virtual reality program is perfect, in the sense that it supplies me with all the perceptible qualities I could perceive in a real body? For the scholastics my judgment would still be false, since my concept of a body even in this case cannot truly apply to a however perfect illusion. By contrast, since on empiricist grounds my idea of body is but the collection of its perceptible qualities, in such a situation, if the illusion is truly perfect, my judgment should be true according to Hume.

On the other hand, for Descartes, the same judgment under the same circumstances would be false, too, just like for the scholastics. Still, there is a tremendous difference between the Cartesian and the scholastic account of the matter, with far-reaching consequences, even if this is quite difficult to recognize in a superficial comparison. At the bottom of the difference is that for Descartes our ideas are representations which are not necessarily connected to their objects. Just remember that in the midst of demon doubt we were supposed to have exactly the same ideas, but without any real objects they appeared to represent, which is a situation Descartes clearly finds conceivable. (So, this is not just an inconceivable possibility of the kind Descartes finds producible by divine omnipotence, so his unorthodox view on divine omnipotence being capable of making contradictories true is not relevant here.) Indeed, in the Cartesian framework it is also perfectly conceivable that I could have exactly the same ideas, if I had been in touch only with a virtual reality in all my life. What is more, this holds not only for me but for any human being. So Descartes finds it possible not only that my particular judgment is wrong when I try on the virtual reality gear, and which I can correct as soon as I take the gear off, but that all judgments of all humanity may be wrong in the same way, incorrigibly by any former or later experience, for we may be cut off from reality completely and forever by the trickery of an omnipotent deceiver.

By contrast, again, according to Hume such a situation is absolutely possible, but Descartes is just wrong in saying that in this case all humanity would be wrong. Not at all. In this situation, which may very well be our actual situation, it is only this virtual reality which it makes any sense to call reality, and in fact it is only this sensible reality that we call reality. And this is so, even if there may or may not be some other, hidden, more real reality of which we can have no idea at all.

On the scholastic account, however, such a situation would be simply impossible. For this kind of objective, but in principle undetectable falsity of all our factual judgments would imply that all our concepts could be exactly the same as they are when they apply to real objects, only in this hypothetical situation of perfect illusion, none of them happens to apply to any real object. But then the very same concepts, which in a normal situation would be the forms of real things in the mind without the matter of these things, are supposed to be not the forms of any real thing in this hypothetical situation. But as we saw earlier, this supposition leads to the contradiction that our concepts both are and are not the forms of things in the mind without their matter.

But that the hypothesis of complete illusion of the demon argument is contradictory also in itself, can be shown by the following reasoning. In the description of this hypothetical situation we necessarily have to use some concepts which adequately apply to this situation. But this can be so, only if by these concepts we adequately conceive of the real things occurring in that hypothetical situation. On the other hand, in the description of the same situation it is also said that in that situation we can have no concepts by which we could conceive of the real things of that situation. So our hypothesis can possibly be true only if our actual situation, in which we describe that hypothetical situation is not the same as that hypothetical situation. On the other hand, it is also part of the demon-hypothesis that our actual situation can be identical with the hypothetical situation of complete illusion. So this hypothesis leads to a contradiction, namely that our actual situation both can and cannot be that hypothetical situation. For the assumption of the possible truth of the hypothesis implies that our actual situation cannot be that hypothetical situation, while the hypothesis also states that our actual situation can be that hypothetical situation. But then, since the hypothesis of complete illusion implies contradiction, it follows that the demonic situation of complete illusion cannot be our actual situation, and so in our actual situation at least by some of our concepts we necessarily latch onto real things, which these concepts appear to represent. So the scholastic Aristotelian claim concerning the necessary connection between concepts and their adequate objects seems to have a pretty firm foundation in itself, without having to rely on the notion of causality between objects and their mental representation.

But then, since on the basis of this scholastic Aristotelian account, at least some of these concepts have to be substantial concepts, as no accidents are conceivable without conceiving the substance which they are the accidents of, by these substantial concepts we have to conceive of the real essences of these real things. And this is so even if we are not always able to re-identify these real essences by means of other concepts, supplying some reliable real definition of the thing. But then, we can be sure, a priori, that things having such essences are going to have their essential properties as long as they exist, since for a thing to exist is to have this essence constituted by its substantial form, even if we may not always know what exactly these essential properties are. And so we can be sure that things of the same kind, having the same essences, are going to behave according to the same unchanging causal laws determined by their essential properties as long as they exist. Therefore, we can also be sure that as long as the world as we know it exists, that is, as long as it is going to have a future at all, its future is going to resemble its past in respect of these essentials. Well, of course nothing guarantees that the world is going to exist in the next moment, as the world is contingent. God can annihilate this world anytime. But that time would be just the end of time, so beyond that point, of course, it's no use asking whether the future will be like the past. So we can be absolutely sure that as long as this world exists, consisting of the kinds of things it actually does, it is going to obey the causal laws determined by the essences of things making it up.

As we can see, moving back in time, in the scholastic Aristotelian account of substance and the way it is related to our concepts we could finally find a firm, independent foundation for the idea of necessary causal laws, based on the real essential properties of really existing things, which we can be sure our concepts adequately represent. But this kind of abstract, metaphysical certainty could of course never yield in itself any specific knowledge concerning what the real essences of particular kinds of things are. On the other hand, by the time of Descartes, it was precisely the lack of this kind of specific knowledge that rendered scholastic explanations the common target of the mockery of a new intelligentsia, whose interests demanded precisely this kind of knowledge. Therefore, they naturally detested the scholastics' abstract references to substantial forms determining the causal powers of things. That opium puts you to sleep because it has dormitive power, i.e., a power to put you to sleep, is a truism, but a truism which for Molière, a younger contemporary of Descartes's, already served only to ridicule the "science" of the Schools.

But then it should come as no surprise that Descartes wanted to find different foundations for the science he conceived of, in which therefore, there was no place for such "obscurantisms". As a consequence, Descartes abandoned substantial forms from his ontology and the corresponding view of substantial concepts from his epistemology. On the other hand, we just saw that it was precisely this, general metaphysical and epistemological framework, which could provide a strong, independent foundation for the view of physical reality as being directly accessible to us by our mental representations, and as obeying necessary laws providing the intelligible architecture of this reality.

Therefore, having abandoned this metaphysical and epistemological framework, no wonder that it was only by the help of divine grace that Descartes could smuggle back the objects of his ideas which he had thrown out in the beginning by divine omnipotence. As he discarded substantial forms, he could not regard our substantial concepts as the substantial forms of things in the mind without their matter. And so, he regarded his ideas as connected merely contingently to their objects. (In fact, that Descartes could have such a different conception of ideas at all also has an interesting prehistory in late medieval philosophy, but this would lead us too far away from our present subject.) So against the Demon-doubt he could not re-establish the match between ideas and their objects, except by proving that God exists and that He is not a deceiver.

On the other hand, in the possession of this divine guarantee, Descartes was still able to restore a real physical world behind the scenery of our ideas. Indeed, he could still claim that this world obeys necessary laws based on the real essences its real substances have, which we can get to know by using our purely intellectual ideas, by which, in possession of the divine guarantee, we are able to reach out to the unchangeable, mathematically characterizable essences of things.

But besides the internal foundational problem of the Cartesian system expressed in the so-called Cartesian circle, it is evident that this system can account for our having these purely intellectual ideas only by presenting them as innate ideas, while the correspondence of these ideas to their objects was based entirely on the graceful activity of our Creator. Therefore, anyone who wanted to drop the tenets of innate ideas and the divine guarantee, but retain the general Cartesian framework, in which mental representations are related only contingently to their objects, had to try to find some other relationship to account for the match between ideas and their objects.

As we know, this was the course taken by John Locke. He thought that the doctrine of innate ideas was absurd, on the basis that it involves the seemingly strange assumption that there can be something in our minds which we are not aware of, while it seems that to have something in the mind is nothing, but to be aware of it. (Well, then, it is an open question how an English peasant of Locke's time could have the rules of English syntax in mind without ever being aware of these rules, but this is a further issue.) But then, the only source of our ideas seemed to be sense perception. Therefore, according to Locke, it is only through the testimony of the senses that we can know of the existence of an external reality, which by its causal operations on our sense organs generates ultimately all contents of our minds.

But as we could see earlier, Berkeley's criticism of Locke's idea of material substance points out very clearly the incapability of Locke's empiricist principles to generate any intelligible, genuine idea of material substance, as something distinct from a sheer collection of ideas of sensible qualities. But once the idea of material substance is reduced to that of a collection of ideas of sensible qualities, since ideas cannot be except in the mind, Berkeley was completely entitled to drop the idea of independently existing material substance altogether.

On the other hand, for Berkeley this did not involve dropping the idea of substance per se, for he thought he can, indeed, has to retain at least spiritual substances in his ontology. But then, it is a mystery again, how we can have any idea of spiritual substance, if all our ideas should derive from sense perceptions. As his desperate distinction between notion and idea in the second edition of his Principles shows, Berkeley was quite aware of this problem, but he was unable to come up with a satisfactory solution.

So, it was finally Hume, who was the first to push empiricism to its utmost consequences, deleting all kinds of substance from his ontology, including even the substance of the human mind. His relentless consistency, however, drove him to draw such bold consequences, which, instead of revolutionizing philosophy in the way he conceived, led to a thoroughgoing re-examination of the very principles of empiricism. In fact, in this roundabout manner Hume's philosophy eventually did yield a revolution in philosophy, although a revolution of a rather different kind: the "Copernican revolution" of Kant's philosophy.