De Rervm Natvra Constantivm Scientia, Principiis Et Affectionibvs Commvnibvs, Dispvtatio

XXV. Concerning this way of gathering matter, whether it is certain or not, we do not dispute. If anyone looks through all things with a more attentive mind, he might perhaps find a great occasion for doubting; yet, that being posited, we may take this definition of matter from here, with Aristotle as the author: matter is the first subject from which something is made, when it is present of itself and not according to accident; which definition we have expressed in the first book of the Physics, text 28.

XXVI. It is called a "subject," both by reason of action and by reason of form; by reason of the former, because it is not made or produced by that action, but is already posited to exist; by reason of the latter, because it is joined to it as something more imperfect. It is called "first," because it is presupposed for every effect being produced by a natural agent. "From which something is made," because the effect is produced dependently upon it; which is said in other words, that the effect is drawn out from the potentiality of matter.

XXVII. By the final words, the definition is restricted to substantial generation. Whence it is necessary that, although it is perfect according to the intention about which Aristotle treats here, it nevertheless lacks the perfection necessary for a definition absolutely; namely, in that it does not comprehend every effect which we ascribe to matter—when it is signified by this word "matter"—as an adequate one, which is the generation of an accident as well as of a substance. Therefore, if we desire a perfect definition of matter, it might perhaps be this: matter is the first subject from which something is made, namely, an accident and a substance.

XXIIX. From which definition it is first concluded that the essence of matter is contained in potentiality, by which it can receive form, if we abstract our thought from past, present, and future time; that is, so that it can or could have received the form which has existed or will exist. For time is an accident of matter. And this is what others say, that potentiality abstracted from privation is the essence of matter.

XXIX. Secondly, it follows that matter is not pure potentiality (as they speak) in such a way that it lacks everything of which it is truly said that it is something outside of nothing; since it is that from which another is made, when it is present, that is, as if from another part. And from this, by necessary consequence, it is not "pure potentiality," as some interpret, that is, a being in act, but existing only in potentiality; because existence is a passion of being.