286. Matter and Form. -- Purely cosmological in their original meaning, the concepts of matter and form were widened by the scholastics, as by Aristotle (42): in the logical order, formalis and actualis, materialis and potentialis, are synonymous.

Matter and form are correlative elements.^{1} The scholastics were unanimous in recognizing the hylemorphic composition of corporeal substances, all of which they taught to be composed of matter (principle of indeterminateness, potency) and form (principle of determinateness, actuality). But they hotly disputed two questions, of which the second especially -- the one most controverted -- had not attracted the attention of Aristotle (42).

(a) Can matter exist without a substantial form? The earlier scholastics were inclined to attribute to primal matter an existential reality independent of form. Albert the Great and still more St. Thomas, opposed this view, which they regarded as destructive of peripateticism. St. Thomas held that the factors of the corporeal compound were so intrinsically and essentially dependent on each other that Almighty God Himself, unable to effect the impossible, could not give existence to the indeterminate primal matter, without a substantial form as determining principle: the potential, as such, cannot be actual. On the other hand, St. Thomas's rivals at Oxford and Paris were unwilling to follow him in this rigorous interpretation of peripateticism.

(b) Does substantial composition extend to immaterial substances, to the human soul, and especially to the angelic nature -- that connecting-link in the hierarchy of essences between man and God? Angelic life was deeply studied by scholasticism; the scholastics made use of the purest principles of intellectual and appetitive activity to construct an angelic psychology, or rather an "eidology," which has nothing in common with Aristotle's uncertain pronouncements on the motor-intelligences of the world-spheres.

The earlier scholasticism, chiefly of the Franciscan schools, established a complete identity, in the real order, between the two pairs of concepts, act and potency, form and matter; and accordingly they regarded hylemorphic composition as the essential mark of all contingent substances. St. Thomas was the first to protest boldly against this teaching, which had influenced even his own master (269). It is an interesting fact that while St. Bonaventure and his followers were claiming St. Augustine as the first authoritative exponent of their theory, St. Thomas, in the De Substantiis Separatis, traced the theory to its real source:^{2} it is a Jewish importation, he wrote, and the philosophy of the Fons Vitae, so far from being a source of life, is a channel of stagnant water which poisons the pure current of Aristotelianism.^{3}

In opposition to Avicebron's teaching, St. Thomas propounds the theory of the simplicity of immaterial beings -- a doctrine more in keeping with the principles of Aristotelianism. CORPOREAL substances alone, have primal matter as a constitutive element; this is the principle of their spatial extension, of their numerical multiplication and of their imperfection generally. The angelic nature, then, is a "forma separata" -- a form free from matter. Here is St. Thomas's explanation: Seeing that it is the form that actualizes matter and endows the compound with its perfection, and not vice versa, there can be no contradiction in the concept of "formae subsistentes" -- forms subsisting without any admixture of matter. These pure intelligences, intrinsically possible, subsisting apart, or "separated" from matter, are nevertheless contingent and finite, for they are an admixture of act and potency and their essence is limited by their existence. "Quia forma creata sic subsistens habet esse et non est suum esse, necesse est quod ipsum esse sit receptum et contractum ad terminatam naturam. Unde non potest esse infinitum simpliciter."^{4}

In determining the functions of matter and form, scholasticism merely recapitulates peripateticism, with perhaps some slight developments (42). Matter is the passive, homogeneous substrate, incomplete substantially, the principle of change, not itself either being or non-being, and not eternal any more than motion is eternal (293). Form is the determining, constitutive cause of every being, the standard and measure of its perfection, the principle of its intelligibility, the source of its activities,^{5} the seat of those directive, natural inclinations by which it tends towards the realization of its end. Being likewise a principle of unity, it may be understood to gather up, as it were, into one single substantial unit, the scattered elements of the extended matter of corporeal being.

In this connection there arose a controversy which added to Aristotle's teaching and attracted considerable attention during the second half of the thirteenth century: How are we to understand this unitive function of the form? Can a thing be intrinsically endowed with more than one substantial form?

We have seen already how deeply rooted the theory of the plurality of forms was in the earlier schools, when St. Thomas made his appearance there.^{6} He seems to have been influenced by it himself in his student days. His Commentaries on the Sentences -- where, indeed, we find more than one doctrinal peculiarity that disappears in his later and maturer works -- contain some texts which betray a certain amount of hesitation and seem to admit a "forma corporeitatis" as the "prima forma substantialis" of bodies.^{7} But subsequently, throughout all his voluminous writings, St. Thomas defended the unity of the substantial form with a long array of powerful arguments which were called forth by the needs of controversy and which leave no shadow of doubt as to what his real opinion was in the matter. Among his metaphysical arguments is one connecting the unity of form with the transcendental unity of the thing ("nihil est simpliciter unum, nisi per formam unam per quam habet res esse"^{8}), and with the very notion of substantial being; in physics he offers unity of form as an explanation of the generation and corruption of substances; in psychology it explains for him the manifest solidarity of the various vital functions in the individual living thing, the identity of the living man with the individual after resurrection, etc.^{9}

This teaching on the unity of substantial form in the individual has exerted a far-reaching influence on Thomism; it knits together and co-ordinates quite a number of doctrines. St. Thomas owes it neither to his master, who interpreted it in another way, nor yet to the Averroïsts,^{10} but to his own personal penetration of the peripatetic genius of scholasticism.

Similarly, it is not St. Augustine, but Avicenna and the Arabians, that St. Thomas accuses of having been the first to give currency to the pluralist doctrine.

{1} In the logical order the notions are purely correlative. Matter and form here mean simply the determinable and the determinant. E.g., the concepts of genus and species represent objective aspects of the same reality, perfectible the one by the other. In the real order some scholastics admitted the correlation only with reserves.

{2} WITTMANN, Die Stellung d. hl. Thom. z. Avencebrol, p. 40.

{3} Cf. DE WULF, Treatise De Unitate Formae, Introduction, pp. 20, 21.

{4} Summa Theol., I^a, q. 7, a. 2. Some later scholastics admitted the possibility even of simple corporeal beings, in reference to the heavenly bodies (295).

{5} The substance or essence, considered as the internal, root principle of the activities of a being, is styled NATURA; it is through the form (id quo) that the complete, individual essence (id quod) fulfils the function of nature.

{6} J. Peckham could still say about the theory: "tenuit hactenus totus mundus" (EHRLE, J. Peckham, etc., p. 178 (240)).

{7} In I. L. Sent., d. viii., q. 5, a. 2; and II. L., d. iii., q. 1, a. 1. See DE WULF, Le traité De Unitate Formae de Gilles de Lessines, ch. iii.: Thomistic innovations of principles.

{8} S. Theol., q. 76, a. 3, c.

{9} DE WULF, S. Theol., q. 76, a. 3, c.

{10} V. 312, the insinuations of Peckham on this point.