Cursus Philosophicus Thomisticus, Secunda Pars Artis Logicae

This very celebrated and ancient division into ten categories has been accepted on the authority of so many centuries that it would be impious to doubt it. Its rationale, however, is not easily given. St. Thomas explains its adequacy in 5. Metaph. lect. 9.¹ and 3. Phys. lect. 5.² as follows.

Whatever can be predicated of a subject or of a primary substance can be predicated in only three ways: first, as pertaining to its essence; second, as not pertaining to its essence but inhering in the subject; or third, as a predicate drawn from something extrinsic, from which it takes its denomination. If in the first way, it constitutes the category of SUBSTANCE. If in the second, the inhering predicate is either absolute or relative and ordered to another term. If it is an absolute and inhering form, it either follows upon matter or upon form as form, whether the form be spiritual or corporeal. If it follows upon matter, it is QUANTITY, because quantity extends the material parts. If it follows upon form, it is QUALITY, which has the function of qualifying and determining the mode of form. If it is a relative form, it is RELATION.

If, however, predication occurs in the third way, by taking a denomination from something extrinsic on which it depends, it pertains to the six final categories. They are gathered as follows. What depends for its denomination on something extrinsic does so either because that extrinsic thing is a cause or measure, or because it is simply and extrinsically applied, without measurement or causality. If in this last way, it is the category of HABIT, by which someone is said to be clothed. If the denomination comes from something extrinsic that is a cause, it cannot be material or formal, since these intrinsically constitute or denominate through an intrinsic union. Their causalities therefore do not constitute a special category, because they are ordered more to perfecting and completing matter and form themselves, which are perfected in themselves through informing and receiving, than to perfecting and changing other things, as efficient causality does. Modes do not constitute a special category when they merely express some completion of a thing; in that case, they are reduced to the thing whose modes they are. They do so only when they express some special commensuration with substance, not merely a completion or condition of the thing's being. The final cause has only metaphorical causality, and wherever it is real, it coincides with efficient causality. It remains, then, that an efficient cause is an extrinsic source of denomination. In that case it either denominates a subject that is changed, and is PASSION, or the cause from which an effect flows, and is ACTION. If denomination comes from an extrinsic measure, the measure is either place or time. If place, it either measures according to the absolute account of being in a place by way of different distances, and so is WHERE, or by reason of the order of parts in a place, and so is POSITION. If time is the measure, it constitutes the category of WHEN. There are no further extrinsic measures.

In this account of how the number of categories is gathered, SOME FIND A SCRUPLE, especially in two respects.

First, quantity is said to follow matter, and quality form. If this is understood of inherence, according to St. Thomas both inhere in the composite, as is to be explained in the books on Generation.³ If it is understood of emanation, quantity does not emanate from matter alone, but from the composite, which is a body; for a body is what has three dimensions. This does not express matter alone, but matter informed by corporeal form.

Second, St. Thomas seems to constitute the six final categories through extrinsic denomination, which we shall show below to be false when treating them; and it cannot be doubted especially that passion is an intrinsic change. Nor can one say that they are intrinsic modes that nevertheless depend on something extrinsic to which they are related; for on that basis relation too would be called an accident of extrinsic denomination, since it depends on an extrinsic term.

NEVERTHELESS, none of this undermines the sufficiency of the foregoing account of St. Thomas.

For quantity's following upon matter and quality's following upon form is a common saying of the philosophers. It is not founded on emanation from or inherence in matter alone, but on this: quantity is the primary disposition of matter, because its division and indivision are considered according to quantity, as St. Thomas says in 4. dist. 12. q. 1. art. 1. quaestiunc. 3.⁴ and q. 9. de Potentia art. 7.⁵ Hence quantity is found only in material things. It is therefore said to belong to something by reason of matter, because it disposes and orders the material parts; and also because it is proportionate to matter itself, since quantity is not active but is the means by which other accidents are received. In this way it is proportionate to matter, which is the first recipient. Quality, however, is found in both material and spiritual things; it is also a quality that disposes one to act and serves as an active instrument, and therefore is founded on what belongs to activity and actuality, which pertains to form.

To the second point, the answer is that St. Thomas does not constitute the six final categories through extrinsic denomination of the sort “being known,” “being seen,” and so on, which says nothing inhering in the denominated object; rather, only the denominating form inheres extrinsically in something else—for example, vision in the eye, love in the appetite—and that form of love or vision is placed in a category. The denomination by which an object denominates something as seen or loved, since it does not inhere in the object, does not express in it any reality added to vision or love that would constitute a distinct category. Therefore, the extrinsic denominations that St. Thomas places in a category are not purely extrinsic: they posit something intrinsic in the denominated thing, such as “where” in what is located and passion in what is acted upon, though dependently on something extrinsic that not only terminates it but also denominates it or concurs in its denomination. Hence these are sometimes said to be denominated by something extrinsic not formally, but originatively: the denomination of that intrinsic mode originates from, and depends on, something extrinsic.

As for the objection concerning relation and other things that depend on extrinsic terms, the answer is that the cases differ. Relation does not depend on its term as on something that denominates or originates the denomination of the relation, but as on what terminates it. Powers, habits, and acts (and the same holds for relation) do not denominate by means of a term; rather, they direct and order toward it, while the forms themselves denominate intrinsically per se by referring to their terms. The six final categories do not order a subject toward a term, for in that case they would be relation. Rather, they belong to a subject through subordination to and derivation from something extrinsic, on which they depend for denomination. Thus, to make something located, a place depends on what locates it; to make someone clothed, a garment surrounding him is required; to make something a “when,” time is required; to make something acted upon, an agent is required; and to make something an agent, an effect is required. Yet these do not leave behind merely an extrinsic denomination; they leave a real mode by which the subject is changed intrinsically and denominated dependently on something extrinsic, in the way explained.

But you will ask what sort of distinction suffices among the categorial natures themselves to constitute distinct categories. The answer is that some hold one extreme: a real distinction is required, as between two things. Others hold the opposite extreme: a distinction of reason with a foundation in reality suffices, as Father Suarez holds in disputation 39 of the Metaphysics, section 2, no. 22.

THE FIRST OPINION is plainly refuted by the example of certain categories that are only modes, such as action, passion, where, and position, indeed even relation, as we shall say in their respective places below. These are not distinguished per se or by reason of themselves from other categories as one thing from another. On that view there would consequently be fewer than ten categories.

THE SECOND OPINION, first of all, opens the way to positing more than ten categories if a mere distinction of reason suffices. For there would be no reason why final or exemplary causality, for example, could not constitute a distinct category, even if it coincides with action, which is efficient causality, if a distinction by reason suffices. Next, the distinction of categories is a distinction of real beings; therefore, where no real distinction is given, but only one of reason, there is no reason to posit a different category. Third, in fact all categories are either things or real modes, such as relation, action and passion, where and position, which are distinguished from one another as different modes and modally from their subject, as we shall say in question 19. Although place and garment are the same as a surface, they are not distinct categories insofar as they are surfaces; rather, the mode “where,” which results from place, and the mode of being clothed, which results from a garment's being adjacent, constitute different categories. Action and passion are distinguished from one another as modes, although they are identified entitatively in reality with motion or with their subject.

Therefore THE THIRD OPINION is truer: at least a modal real distinction is required, which has been proved by the foregoing.