Marsilio Ficino’s Platonic Theology, Volume II

Twelfth argument: because it has within itself no potency toward non-being.

1Nothing is ever corrupted unless it contains within itself a potentiality not to be. If it were incapable of not being, it would never cease to be. The soul has no such potentiality, because for the Platonists the soul is nothing other than a simple form subsisting in its own right: complete and whole in its own essence, yet also capable of contributing to the formation of an animal species.

2Here the actuality of existing lies in the complete and perfect form itself, for each thing is what it is through the integrity of its form. Thus the proper subject of being is the thing’s own form and essence. Where, then, could the potentiality not to be reside—the potentiality opposed to being itself? In being? But how could one contrary possess a capacity for receiving the other? In the essence? No more there than in being. If the essence, precisely because it is a simple and integral form, is the proper subject of its own being, how could it contain a potentiality for the opposite of that being? How, for example, could the proper substance of fire, which is the proper subject of its heat, possess a potentiality for receiving cold while both becoming cold and remaining fire? Even in mortal bodily substances the potentiality not to be does not belong to them insofar as they are complete in their species and endowed with form—for it is in this respect that they exist—but insofar as prime matter lies beneath them, never resting under any one form. The soul has no such matter. Therefore a potentiality not to be is found nowhere in it, and it is consequently immortal. Let us now unfold this argument more plainly. In things composed of form and matter, matter in a certain sense precedes the finished work.

3Who can doubt that matter in some sense exists before it is formed? Let us take this matter as in some sense preceding the work to be made and ask whether, from the nature of that matter, the work must necessarily come to be, cannot possibly come to be, or merely may come to be. It is not necessary. If it were, matter’s own power would at once impose necessity upon the work and would need no nobler agent to form it. Yet it does need such an agent, because what is formless cannot form itself. Considered solely with respect to matter, therefore, the future work is not necessary.