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

REBVS NATVRALIBVS. original: "On Natural Things"

more excellent in greater perfection according to extension, yet this is enough to prove the proposition: that the composite is simply more excellent than the form. Secondly, it follows that the form is in itself indivisible by the division of extension or quantity, because it is a part of the substance. Yet, one form is divisible by accident, another is not divisible even by accident: forms divisible by accident are those that can be divided into parts by the division of quantity. Such forms cannot exist except in the actual extension of their parts, and for that reason, they demand by their own nature a quantity by which they are actually extended.

XLII. From this, two things are gathered: first, that every substantial form divisible by accident is contained by the reason of the body; second, that quantity belongs to the composite as a proper accident, not to the matter. To which it is a consequence that matter does not have the same quantity numerically affixed to it for all time, but it perishes when the composite perishes, and is generated anew when the composite is generated.

XLIII. Therefore, if there are some who prefer to ascribe quantity to matter as an inseparable accident, it is necessary that they either attribute a perpetual body-form to matter, or assert that both matter and the perfect form of the body hold a reason of the body, though each of a different genus. Although neither of these is very common, we do not consider either a great absurdity.

XLIV. Forms indivisible by accident are those that lack parts entirely, and for that reason cannot be divided or extended; the soul of man is of this kind. In order for these forms to exist in the universe, they do not necessarily need the conjunction of quantity because they are indivisible. From this, it happens that they can be separated from the body, and thus are entirely devoid of body.

XLV. Nevertheless, that which is composed of such a form, such as man, attains the perfect nature of a body. This can be explained in two ways: either we say that, beyond that form indivisible by accident, the composite is formed by some other [thing] from which it obtains the reason of a body, or that the same form, which is indivisible by accident, is of such perfection that, existing in the conjunction of matter, it brings the perfection of the body just as it brings quantity as a due accident. If we follow this latter path, just as we have defined things as univocal having the same meaning, so we shall explain that a composite of this kind is contained by the same or a different univocal reason of body.
And thus far regarding the principles of natural being; it follows that we must deal with its affections.