Chapter IX. Nature And Person.
70. Some Divisions of Substances.—In the preceding chapter we discussed the nature of substance and accident in general, and the relation between a substance and its accidents. We must next examine the category of substance more in detail, terminating as it does in the important concept of personality or person. This latter conception is one which must have its origin for all philosophers in the study of the human individual, but which, for scholastic philosophers, is completed and perfected by the light of Christian Revelation. We shall endeavour to show in the first place what can be gathered from the light of reason about the constitution of personality, and also briefly to note how Christian Revelation has increased our insight into the perfections involved in it. As leading up to the concept of person, we must set forth certain divisions or classifications of substance: into first and second substances, and into complete and incomplete substances.[277]
(a) The specific and generic natures of substantial entities do not inhere, like accidents, in individual substances; they constitute the essence of the latter, and hence these universals are called substances. But the universal as such does not really exist; it is realized only in individuals; in the logical order it pre-supposes the individual as a logical subject of which it is affirmed, a subjectum attributionis seu praedicationis. Hence it is called a second substance, while the individual substance is called a first substance. Of course we can predicate attributes of universal substances, and use these as logical subjects, as when we say “Man is mortal”. But such propositions have no real meaning, and give us no information about reality, except in so far as we can refer their predicates (“mortal”), through the medium of their universal subjects (“man”), back ultimately to the individual [pg 253] substances (John, James, etc.) which alone are real, and in which alone the universal (“man”) has its reality. Hence the individual is, in the logical order, the ultimate and fundamental subject of all our predications. And furthermore, the individual substance cannot be used as a logical predicate of anything underlying itself, while the universal substance can be so used in relation to the individual.
In the ontological order, of course, the universal substance is individualized, and, as individual, it is the subject in which all accidents inhere, their subjectum inhaesionis: the only subject of many of them, and the remote or ultimate subject of those of them which inhere immediately in other accidents.
Thus while in the ontological order all substances, whether we think of them as universal or as individual, are the ultimate subjects of inhesion for all real accidents, in the logical order it is only the individual substance that is the ultimate subject of attribution for all logical predicates. Hence it was that the individual substance (τόδε τί ὄν), vindicating for itself more fully the rôle of subject, was called by Aristotle οὐσία πρώτη, substantia prima, while he called the universal, specific or generic substance, οὐσία δεύτερα, substantia secunda.[278] These are, of course, two ways of regarding substance, and not two really distinct species of substance as genus. The distinction between the membra dividentia is logical, not real.
The perfectly intelligible sense in which Aristotle and the scholastics designate the universal a substance, the sense of moderate realism, according to which the universal constitutes, and is identical with, the essence of the individual “person” or “thing,” is entirely different from the sense in which many exponents of modern monistic idealism conceive the universal as the substance par excellence, the ens realissimum, determining, expressing, evolving itself in the individual phenomena of mind and of nature, which would be merely its manifestations.[279]
(b) The divisions of substance into spiritual and corporeal, of the latter into inorganic and organic, of these again into vegetative and animal, and finally of animal substances into brute animals and human beings,—offer no special difficulties. All purely natural or rational knowledge of the possibility and nature of purely spiritual substances is based on the analogy of our knowledge of the human soul, which, though a spiritual substance, is [pg 254] not a pure spirit, but is naturally allied with matter in its mode of existence. The individual human being offers to human experience the sole example of the sufficiently mysterious conjunction and combination of matter and spirit, of the corporeal mode of being and the spiritual mode of being, to form one composite substance, partly corporeal and partly spiritual.
(c) This in turn suggests the division of substances into simple and composite. The latter are those which we understand to be constituted by the natural and substantial union of two really distinct but incomplete substantial principles, a formative, determining, specifying principle, and a material, determinable, indifferent principle: such are all corporeal substances whether inorganic, vegetative, sentient, or rational. The former, or simple substances, are those which we understand to be constituted by a sole and single substantial principle which determines and specifies their essence, without the conjunction of any material, determinable principle. We have no direct and immediate experience of any complete created substance of this kind; but each of us has such direct experience of an incomplete simple substance, viz. his own soul; while we can infer from our experience the existence of other incomplete simple substances, viz. the formative principles of corporeal substances, as also the possibility of such complete simple substances as pure spirits, and the actual existence of the perfectly simple, uncreated substance of the Infinite Being.