Marsilio Ficino’s Platonic Theology, Volume II

6Yet it unites into one both what does not yet exist and what no longer exists. In attending to temporal things it stands above time; in attending to moving things it remains unmoved. Why, then, should its substance not be immortal while it concerns itself with mortal things? Indeed, why should it not become perpetual as it reaches perpetual things, since it remains unmoved while handling things in motion? Moreover, what makes a body be body is not so much its bulk as its form. A body is body to a greater degree the more shapely and beautiful it is, and to a lesser degree the more ugly and deformed; that deficiency arises not because some bulk has been cut away but because form has been lost. We must therefore hold that the mind—the principle from which body receives the form through which it is body and the connection of parts through which it coheres—can never be deprived of its own form or of the unity through which it is and remains a mind, since a body is never deprived of every form and unity through which it is and remains a body. Yet the soul does not pass from species to species as body does, for change descends from the soul into the body, and the soul is more stable than body. Therefore, if body always remains within the bodily genus, the soul always remains within the species of soul. Nor within that species will it be changed from one soul into another, since no matter underlies it through which such a change could occur. If no such change occurs, and if the mind cannot exist without living, the mind certainly never dies.

7Suppose someone says that the destruction the mind should fear is not the one by which something becomes nothing, but the one by which we call dead whatever lacks life. Let him observe that no thing can lack itself. The mind is a certain life. Hence what is ensouled is understood to live, while anything without soul that is capable of being ensouled is understood to be dead—that is, deprived of life. The mind, therefore, cannot die.