Moreover, our conception of _materia prima_ as an imaginary point in space may help us to realize more completely the distinction which must be made between the non-entity of the first matter and absolute nothingness. Absolute nothingness is a mere negation of being, or a _negative_ non-entity; whereas the non-entity of the first matter is formally constituted by a privation, and must be styled a _privative_ non-entity. For, as the matter and its substantial form are the constituents of one and the same primitive essence, we cannot think of the matter without reference to the form, nor of the form without reference to the matter. And therefore, when, in order to conceive the first matter, we suppress mentally the substantial form, we deprive the matter of what it essentially requires for its existence; and it is in consequence of such a process that we reduce the matter to a non-entity. Now, to exclude from the matter the form which is due to it is to constitute the matter under a privation. Therefore the resulting non-entity of the first matter is a privative non-entity. Indeed, privation is defined as “the absence of something due _to a subject_,” and we can scarcely say that a non-entity is a subject. But this definition applies to _real_ privations only, which require a _real_ subject lacking something due to it; as when a man has lost an eye or a foot. But in our case, as we are concerned with a pure potency of being, which has no reality at all, our subject can be nothing else than a non-entity. This is the subject which demands the form of which it is bereaved, as it cannot even be conceived without reference to it. The very name of _matter_, which it retains, points out a _form_ as its transcendental correlative; while the epithet “first” points out the fact that this matter is yet destitute of that being which it should have in order to deserve the name of _real_ matter. But, much as this notion of the first matter agrees with that of “pure potency” and of “first potency,” the followers of the peripatetic system will say that _their_ first matter is something quite different, as is evident from their theory of substantial generations, which would have no meaning, if the first matter were not a reality. Let us, then, waive for the present the notion of “_pure_ potency,” and turn our attention to that of “_real_ potency,” that we may see what kind of reality the first matter must be, when the “first matter” is identified with the matter actually existing under a substantial form.