ON THE SOUL [BOOK] A, CHAPTER 5

C But let us turn aside for a moment, or rather, let us make our discourse a little easier: let us say that a living body is a natural composite body which is distinguished from a non-living body by its soul, and not by its body. Its soul is within it; and that which is within a thing and acts as its form original: "forma"; in medieval philosophy, the "form" is the organizing principle that makes a thing what it is. is indeed its form. Therefore, the soul is a form. Furthermore, forms are perfections original: "perfectiones"; here meaning the fulfillment or "actuality" of a thing's potential.; for through them the essences of things are completed and perfected. The soul, therefore, is a perfection.

Now, perfections are divided into two types: they are either the principles (or sources) of operations and impressions, or they are the operations and impressions themselves. One of these two is the first perfection, and the other is the second perfection. The principle or source is the first perfection, while the operation or resulting impression is the second. Thus, the soul is the first perfection, because it is the principle that does not proceed from any prior principle [within the body].

D Among perfections, some are inherent in bodies, and some are inherent in non-corporeal substances. The soul, however, is the first perfection of a body. Now, among bodies, some are artificial and some are natural. The soul is not the perfection of an artificial body such as a tool or a statue; therefore, it is the first perfection of a natural body.

But among natural bodies, some complete their operations through the mediation of instruments or organs, while c others do not complete their operations through organs or instruments—such as simple bodies referring to the four elements: earth, water, air, and fire—and operations which E occur through the mastery of simple powers. And if we wish, let us say that among natural bodies, there are some in which a power exists such that vital operations proceed from their essence of their own accord; F and there are some in which this does not exist.

Furthermore, the soul is not the perfection of the "ultimate parts" or the "ultimate members" the basic material components which belong to the two types or divisions mentioned before. Therefore, the complete definition of the soul is this: we say that it is the first perfection (or first act) of an organic natural body. And if we wish, we may say that the soul is the first perfection of a natural body having life in potentiality—that is, a body from which vital operations can potentially proceed. Now, therefore, we have categorized the soul according to its genus and we have defined it; and this is what we intended to declare.

Anima (Soul) — The animating principle of life.
Corpus uiuens (Living body) — A body organized by a soul.
Forma (Form) — The essence or defining nature of a thing.
Perfectio prima (First perfection/actuality) — The state of being prepared or having the capacity for life, like a person who knows how to speak even when they are silent.
Actus primus (First act) — A synonym for first perfection.
Corpus naturale organicum (Organic natural body) — A body made by nature that uses specialized parts (organs) to function.
Potentia uitam habentis (Having life in potentiality) — Possessing the internal capacity to perform living functions.