Predicables

For your convenience, here is a brief summary of Porphyry’s main divisions. Notice though, that Porphyry also lists several other possible interpretations of these terms, nevertheless, it is the ones provided below that came to be the technical interpretations of these terms as they were used in medieval logic.

Predicables (those things that can be predicated of many—whatever they are in their own nature, be they universal words, concepts, or universal entities).

1.1. Essential predicables (i.e. ones that cannot become false of their subject without the destruction of the subject)

1.1.1. Those that reply to the question: “What is it?”

1.1.1.1. Genus—i.e. a predicable that is predicable essentially of many things that differ specifically in reply to the question: “What is it”?

1.1.1.2. Species—i.e. a predicable that is predicable essentially of many things that differ only numerically in reply to the question: “What is it”?

1.1.2. Those that reply to the question: “What is it like?”.

1.1.2.1. Difference— i.e. a predicable that is predicable essentially of many things in reply to the question: “What is it like”?, or ‘What sort of thing is it?”

1.2. Accidental predicables (i.e. ones that can become false of their subject without the destruction of the subject)

1.2.1. Property, an accidental predicate that is inseparable and is predicable convertibly of its subject

1.2.2. Accident, any accidental predicate that is not predicated convertibly of its subject

1.2.2.1. Separable, which may become false of its subject and it occasionally does so by nature.

1.2.2.2. Inseparable, which might become false of its subject, but it never does so by nature, it is only conceivable that the subject persists without this accident.