II. The Universal Concept, Formally Considered (7)

2. The univocal universal

2.1. The univocal universal in genere

a) Notion

The univocal universal is a concept which is predicable in the same way as each of its inferiors.

b) Division

Let us begin by induction by means of an example. Consider Peter, and let us ask ourselves with regard to him the fundamental philosophical question: 'What is Peter'? I can attribute to him the concept of 'man', or that of 'animal'. In the first case, I attribute to him his own essence, while in the second, I attribute to him only a part of it. I can then attribute predicates to Peter like 'capable of laughing', or 'white'. In the first case, I attribute to him a property which characterizes his nature, while in the second case I attribute to him a quality which pertains to his individuality, but which is unrelated to his human nature. Returning to the level of essence, I can even say 'Peter is rational', attributing to him that part of his essence which differentiates him from animal.

We are now able to deduce the five possible ways in which, according to Porphyry*, a univocal universal can be predicated of a subject:


attributable univocal uiniversal............................predicable
- necessarily
--- signifying the essence
----- totally......................................................species
----- partially
------- determinable part..........................................genus
------- determining part...........................................specific difference
--- not signifying the essence.....................................property
- contingently.....................................................accident

This porphyrian structure of predicables is not immune to platonism, as it only considers things from the perspective of comprehension.

Aristotle had already proposed in his celebrated text of the Topics a deduction of the predicables, more formal insofar as it shows the relations between the universals among one another, more coherent with moderate realism insofar as it considers things not only from the perspective of comprehension, but also that of extension:

For every predicate of a subject must of necessity be either convertible with its subject or not: and if it is convertible, it would be its definition or property, for if it signifies the essence, it is the definition; if not, it is a property: for this was what a property is, viz. what is predicated convertibly, but does not signify the essence. If, on the other hand, it is not predicated convertibly of the thing, it either is or is not one of the terms contained in the definition of the subject: and if it be one of those terms, then it will be the genus or the differentia, inasmuch as the definition consists of genus and differentiae; whereas, if it be not one of those terms, clearly it would be an accident, for accident was said' to be what belongs as an attribute to a subject without being either its definition or its genus or a property. Topics A, 8, 103b6-19

* Cf. for example Porphyry, Isagoge 2, 22 - 3, 19. The division is adequate, as St. Thomas notes: CG 1, 32, n. 286:

Omne quod de pluribus univoce praedicatur, vel est genus, vel species, vel differentia, vel accidens aut proprium.

CG 1, 32, n. 286whatever is predicated of many things univocally is either a genus, a species, a difference, an accident, or a property.