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

XXX. What others say, that matter is pure potentiality—that is, it is a being, and exists formally by the existence of the form—is in almost the same genus. For matter is a being in reality distinct from form. Therefore, it must have an existence different from the existence of form, just as other things that are constituted by different essences also differ by this very fact in their existences.

XXXI. Even though Saint Thomas sometimes wishes matter to be pure potentiality, it is not to be accepted, as some accept it, as if he said that matter excludes every ratio of being from itself; but it must be understood: that the essence of matter is closed to be of such a kind by its own nature, that it is at the same time intimately a potentiality of receiving a form. This is true, and it is rightly gathered from that axiom of the philosophers and Saint Augustine: matter is the lowest in being. We concede this; otherwise, if it existed assembled as if from several perfections—which is necessary to happen if it comprehends something in its essence that is not potentiality—not matter itself, but some part of it would hold the lowest place in the universe.

XXXII. Furthermore, the potentiality of matter, which receives a form, when it is known by comparison to a future form due by nature through the action of a natural agent, is called "appetite." It is by similarity to natural appetite, which properly takes the naming of appetite by reason of the form which it acquires by its own operation.

XXXIII. From which three things follow: Appetite is distinguished from potentiality only by reason. Appetite is said to come to matter extrinsically by reason of a contingent concept predicable of matter; which, because it represents potentiality with respect to a contingent effect, which is the future form, for that reason is said contingently of matter. Finally, matter lacks appetite with respect to forms perfected by art (if indeed they are distinguished in reality from matter) because they are not due to matter by the action of a natural agent.