note a privation is permanent, whereas that which does is transient". Tlie connotation of a privation hraits primordial matter to that which is realized by a form disposing it towards reaHzation by certain other definite forms. "Privation" is the absence of those forms. Permanent matter is matter considered in the highest degree of abstraction, and connoting thereby no more than its correlation to form in general.
(6) The Unity of Mailer. — Fmlher, this (permanent) matter is said to be one; not however, in the sense of a numerical unity. Every corporeal being is held to re- sult from the union of matter and form. There are in consequence as many distinct individual realized por- tions of matter as there are distinct bodies (atoms, for example) in the universe. Nevertheless, when the severally determining principles and privations are abstracted from, when matter is cognized in its great- est abstraction, it is cognized as possessing a logical unity. It is understood without any of those disposi- tions that make it differ numerically with the multipli- cation of bodies (De Principiis Naturee).
(7) Matter as the Principle of Individv/ition. — More important is the doctrine that grounds in matter the numerical distinction of specifically identical corporeal lieings. In the general doctrine of St. Thomas, the individual — "this thmg" (hoc aliquid) — is a primor- dial substance, indivitlualized by the fact that it is what it is ("Substantia individuatur per seipsam": Summa, Pars I, Q. xxix, a. 1). It is intrinsically com- plete, capable of subsisting in itself as the subject of accidents in the ontological order, and of predicates in the logical. It is undivided in itself, distinct from all other, incommunicable (cf. De Principio Individua- tionis). These characteristic notes are realized in the case of two substances that differ by essence. Thus, for St. Thomas, no two angels (q. v.) are specifically identical (Summa, Pars I, Q. 1, a. 4). More than this, even a corporeal form, however material and low in the hierarchy of forms, would not be other than unique in its species, if it could exist (or be thought), apart from its relation to matter (cf. De Spiritual. Creaturis, Q. i, a. S). Whiteness, if it could subsist without any subject, would be unique. If a plurality of such accidental forms could subsist they also would differ specifically — as whiteness, redness, etc. But this distinction evidently does not obtain in the case of a number of individuals belonging to one species. They are essentially identical. How is it, then, that they can constitute a plurality? The answer given by St. Thomas to this question is his doctrine of the Principle of Individuation. Whereas the plurality of simple substances, or " forms ", is due to a real dif- ference of their essences (as a triangle differs from a circle), the plurality of identical essences, or "forms", supposes an intrinsic principle of individuation for each (as two triangles realized in two pieces of wood). Thus, simple substances differ by reason of their nature, formally; while composite ones differ Ijy rea- son of an inherent principle, materially. They are multiplied within a given species by reason of matter.
At this point a peculiarly delicate question arises. The alistract essence of man connotes matter. If, then, primordial matter be the principle of individua- tion, it would seem that the alffitract essence is already individualized. Wherein would lie the admitted dif- ference between the species and the individual? On the other hand, if that be not the case, it would appear equally evident that, in adding to the individual a principle not contained in the abstract essence, it would no longer be an object of classification in the species. It would not be merely the concrete realiza- tion of the essence, but something more. In either case the doctrine would seem to be incompatible with modern Realism. St. Thomas avoids the difficulty by teaching that matter is the principle of individuation, but only as correlated to quantity. The expressions that he uses are " materia signata ", " materia subjecta
dimensioni " (In Boeth. de Trin., Q. iv, a. 2), " materia sub certis dimensionibus " (De Nat. Mat., iii). This needs some explanation. Quantity, as such, is an acci- dent; and it is evident that no accident can account for the individuality of its own suljject. But quantity results in corporeal substance by reason of matter. Primordial matter, then, considered as such, has a relation to quantity consequent upon its necessary relation to form (De Nat. Mat., iv). When actuated by form it has dimensions — the " inseparable concom- itants that determine it in time and place" (De Prin- cip. Individ.). The abstract essence, then, embracing matter as it does form, will connote an aptitude or potentiality towards a quantitative determination, necessarily resultant in each concrete subject realized. Here, as formerly, the fact must not be lost sight of that the reasoning begins with the concrete bodies actually existing in nature. It is by an atistraction that we consider matter without the actual quantity that it always exhibits when realized in corporeal sub- stance. Peter, as a matter of fact, differs from Paul, yet they are specifically identical as rational animals. Peter is "this" man, and Paul is "that", but "this" and " that ", because " here " and " there ". " Form is not individuated in that it is received in matter, but only in that it is received in this or that distinct matter, and determined to here and now" (In Boeth. de Trin. Q. iv, a. 1). It is evident that "here" and "now" are the immediate and inseparable signs for us of the indi- vidual. They indicate " hwc caro et ossa ". And they are only possible by reason of (informed) matter, the ground of divisibility and location in space. Still, it must be noted that "materia signata quantitate" is not to be understood as primordial matter having an aptitude towards fixed and invariable dimensions. The determined dimensions that are found in the existing subject are to be attributed, St. Thomas teaches, to matter as "individuated l)y indeterminate dimensions preunderstood in it " (" In Boeth. de Trin.", Q. iv, a. 2; " De Nat. Mat.", vii). This remark explains how an individual (as Peter) can vary in dimension without varying in identity; and at the same time gives the reply of Aquinas to the difficulty raised above. Primordial matter, as connoted in the essence, has an aptitude towards indeterminate dimen- sions. These dimensions when realized arc the ground of the determined dimensions (ibid.) that make the individual hie et nunc au object of sense-perception (De Nat. Materise, iii).
(8) The C'ausality of Matter. — Since Primordial Matter is numbered among the causes of corporeal being, the nature of its causality remains to be con- sidered. (See C.\usE.) All scholastics admit its con- currence with form, as an intrinsic cause; but they are not unanimous as to the precise part it plays. For Suarez it is unitive; for John of St. Thomas receptive. The Conimbricences place itscau.sality in both notes. It would, perhaps, seem more consonant with the <loc- trine of St. Thomas to adopt Canlina! Mercier's opin- ion that the causality of matter is first receptive and second unitive; provided always that its essential potentiality be never lost sight of.
(9) Variant Theories of Matter.— The teaching of Aquinas has been given as substantially identical with that of Aristotle. The main point of divergences lies in the opinion of .\ristotle that the world — and conse- quently matter— is eternal. St. Thomas, in accepting the doctrine of Creation, denies the eternity of primor- dial matter. It is interesting to note how this doctrine of matter, as the potential, or determinable, element in change, unites and corrects the views of Heraclitus, Parmenides, and Plato. The perpetual flux of the first is found in the continual transformations that take place in material nature. The changeless " one " of the second is recognized in the abstract essences eternally identical with themselves. .\nd the world of " ideas " of Plato is assigned its placeas a world of intellectual