Life and Death

And the Lord God formed man of the slime of the earth: and breathed into his face the breath of life, and man became a living soul.
And the Lord God had planted a paradise of pleasure from the beginning: wherein he placed man whom he had formed.
And the Lord God brought forth of the ground all manner of trees, fair to behold, and pleasant to eat of: the tree of life also in the midst of paradise: and the tree of knowledge of good and evil.

Of natural bodies some have life in them, others not; by life we mean self-nutrition and growth (with its correlative decay). It follows that every natural body which has life in it is a substance in the sense of a composite.

But since it is also a body of such and such a kind, viz. having life, the body cannot be soul; the body is the subject or matter, not what is attributed to it. Hence the soul must be a substance in the sense of the form of a natural body having life potentially within it. But substance is actuality, and thus soul is the actuality of a body as above characterized.