Cursus Philosophicus Thomisticus, Secunda Pars Artis Logicae

TWO THINGS MUST BE NOTED HERE: First, concerning the defined thing of these definitions, by which the predicable and subjectable species are defined (we set down the definitions at the beginning of the preceding article); second, concerning the parts of the definitions themselves that must be explained.

Concerning the first, the same must be said about the defined thing of these definitions as was said about the defined thing of genus in the preceding question¹; for the account is the same in one case and the other.

Concerning the second, as regards explaining the parts of the definition, a common difficulty seems to arise: these definitions apply to things other than what they define. For a subjectable species is said to be that which is placed under an assigned genus, or of which the genus is predicated in answer to “what.” But both descriptions apply no less to an individual, since an individual too is placed under a genus and the genus is predicated of it in answer to “what.” If you say that a species is placed immediately under a genus, whereas an individual is not, this is to add a new part to the definition—namely, the word “immediately”—which the definition does not contain. Besides, the case of generic individuals is an objection, such as this animal, this body, and so on, of which genera are predicated immediately. Similarly, the definition of a predicable species applies to things other than what it defines. First, because it applies to genus: a genus too is predicated of individuals in answer to “what”; and although it is predicated incompletely and in a way different from a species, this is not explained in the definition of species, so that the definition is deficient. Second, many things are predicated of many numerically distinct things without being species, such as incomplete beings—for example, motion, soul, matter, a point, and the like—and God is predicated of the three persons, yet is not a species. Third, the third predicable is also predicated in answer to “what,” that is, essentially, and of many numerically distinct things, as in the case of atomic species. Finally, the species of angels truly are species, yet they are not predicated of many numerically distinct things, because such many things are impossible, as we shall say in the next article.

THE ANSWER IS that these definitions are nevertheless rightly given. There is no need to dwell on whether they are essential or descriptive. For just as we said that the definition of genus is descriptive because it is given through the proper property of universality, which is predicability, so the definitions of species must be judged descriptive: the predicable species is defined through its property of predicability itself, which is a property of universality, while the subjectable species is defined through the property of specific universality, insofar as this universality is imperfect and dependent on the universality of genus.

To the first objection against subjectable species, then, the answer is that in all these definitions of the predicables their proper genus, which is the universal, must be understood. The definition therefore means that species is a universal placed under a genus, and difference is a universal predicated of many in answer to “what sort,” and so on for the others. This does not add any extraneous part to the definition, but supplies something necessarily presupposed. For the universal is the genus of the five predicables, and therefore must necessarily be understood in every predicable. Consequently, the part “immediately” must also be understood: species is that which is subject to a genus immediately, since here we deal only with what is subject to a genus as a universal, or as one of the five predicables. An individual, by contrast, is not subject as a universal, and therefore is not subject immediately.

The objection concerning generic individuals is answered by saying that they are not subject as a universal or, strictly speaking, immediately, but only in a qualified sense and as regards explanation. For when one says “this animal” or “this body,” one explains a generic level together with individuation; nevertheless, something not expressed in that generic individual intervenes between individuation and genus. For in reality no animal or body is found as singularized except through a species. A species, however, is subject to a genus so fully and strictly that not only is nothing said to intervene, but nothing can intervene in it between the species itself and the genus. This is what it means to be subject immediately in the strict and absolute sense.

To the second objection against the definition of predicable species, the answer is that, as we said in the preceding question, genus is not formally and immediately predicated of many numerically distinct things, but materially—that is, because they are contained under a species of which it is predicated per se, formally, and directly. Thus the predication of genus must be understood as being in answer to “what,” but incompletely. This does not add anything to the definition; it explains what is already implicit in it. For if genus is predicated of things differing in species, it cannot predicate the whole quiddity, but only a part: that which can be contracted by a difference and, together with the difference, constitutes a species. This is to be predicated in answer to “what” incompletely: not the whole and complete quiddity, but the part that is genus.

To the second point, the answer is that incomplete beings belong to species or genus only reductively, and not per se, just as they do to a category. Hence they have many numerically distinct instances only reductively and in a qualified sense. God, however, is not predicated of the three persons as something that can be multiplied and contracted in them, but as one singular nature predicated of several supposits of the same singular nature. Therefore neither does the divine nature function as a universal, nor do the persons function as inferiors contracting a higher nature and distinguishing it numerically. Rather, the supposits are multiplied without the nature being multiplied: there are three supposits of the same singular nature.

To the third point, we have already said above, in the preceding question,² that difference is indeed predicated essentially, but not in answer to “what,” because it is not predicated substantively but adjectivally or qualificatively. Thus, although it is predicated in answer to “what” with respect to essence, it is not so with respect to mode: it is not predicated essentially in a substantive manner, but essentially in an adjectival manner, or in answer to “what sort.”

The answer to the final point will be given in the following article.