Marsilio Ficino’s Platonic Theology, Volume II

8Hence the soul can be neither a body nor a form divided throughout the body, since it is the subject of indivisible qualities. Just as a man raves if he asks how large knowledge or justice is, or supposes geometry to be smaller than the geometer’s body, so a man is senseless if he asks how large the soul is or supposes it to be smaller than the body, since it is in no way bodily. It not only receives incorporeal things, but also makes many things incorporeal within itself when it conceives the forms and principles of things and habits, above all when it constructs definitions of incorporeal things. Who would call bodily that which is the cause of incorporeal things? Or who would call mortal what is the subject of virtues, when the office of the virtues is to oppose mortal things—for contemplative virtue flees them, while moral virtue drives them away? A quality cannot oppose its own subject. That which is the natural receptacle of qualities whose proper function is to resist and rule mortal things must therefore be immortal. The force of this argument lies especially in the fact that the soul is not only the subject of such qualities but also their principle; consequently, it is from the soul that they receive their nature of opposition to mortal things.