PROPOSITION XLIV.

The substantial Form, though the primary, is not the adequate intrinsic constitutive, principle of Individuation in material substances.

As the form of the Enunciation suggests, this Thesis consists of two parts. These will be considered separately.

I. That the substantial Form is the primary intrinsic principle of Individuation, is a truth commended to us by the authority as well of the Philosopher as of the Angelic Doctor. The former thus speaks: 'We assert, then, that Substance is one of the Categories of Being; and that this substance is partly what is called Matter, which by itself is not this Individual; and partly Form and specific Difference, by which a thing is at once denominated individual and, lastly, the Composite of both.'^{1} The latter tells us that 'Every single thing, by virtue of that same constituent by which it has being, has individuation;'^{2} while, in another place, he offers a Minor to the syllogism by adding that 'Matter receives Form, in order that, by the Latter, it may be constituted in some kind of specific Being.'^{3} Therefore, it is the substantial Form which principally individuates the Composite, by individuating the Matter.

Furthermore, a sufficiently valid argument may be drawn from analogy. For in any given Species, the Genus, which metaphysically answers to the material part, is subordinate, indeterminate, potential; while the specific Difference (or, speaking metaphysically, the formal part,) as the specific Act, determines and, as it were, individuates the Species. A pari, in the Individual Substance, the Matter is subordinate, potential, in itself indeterminate and indifferent; while the individual Difference or substantial Form, as the individual Act, determines and individuates the material Substance.

This truth may be further confirmed by an illustration. Suppose additional Matter, in the way of food, to be received by any given animal. That Matter is assimilated and becomes part of that animal, i.e. it becomes included under its Haecceity. On the other hand, suppose the body of that animal to be informed by another soul from what it had before; it would receive another individuation, distinct from that which it had before.

II. In THE SECOND MEMBER of this Proposition it is declared, that the substantial Form is not the adequate intrinsic principle of Individuation in material Substances. This is sufficiently plain; for the Matter enters intrinsically, essentially, into the composition of such substances. A man, for instance, is not only this soul, but he is likewise this flesh, these bones, -- in a word, this body.

{1} legomen genos en ti tôn ontôn tên ousian, tautês de to men hôs hulên, hauto men ouk esti tode ti, heteron de morphên kai eidos, kath ên legetai tode ti, kai priton ti ek toutôn. De Anima, ii, c. i, in init.

{2} 'Unumquodque secundum idem, habet esse et individuationem.' De Anima, a. ad 2m.

{3} 'Materia enim recipit formam, ut secundum ipsam constituatur in esse alicujus speciei.' 1ae L. 2, ad 2m.