On the Immortality of the Soul

What is usually brought forward in general for the immortality of the soul; and how rationally they have spoken who have disputed for or against it.

...[thought] otherwise than Alexander and Averroes have judged; immediately thereafter, I shall make known how variously each of them is regarded. Finally, I shall bring forward the opinions of those who, following either Alexander or themselves in asserting mortality, and I shall indicate the passages by which they were moved to contend that Aristotle so thought; and from those same passages I shall show that most powerful arguments are drawn to assert the immortality of the soul, so that their own weapons with which they assault immortality may be turned back against their own mortality.

Reasons are taken from various authors to prove the immortality of the soul: from the elevation of that power by which we understand; likewise from the fact that it is sufficiently established that the soul is more perfected, rather than corrupted, the more it is distanced from the body and its functions through its own operation, which properly indicates and manifests the nature from which it flows; also from the fact that it contemplates those things which are least subject to corruption. For that which perfects, it fits and accords with that which is perfected by a just reason; [the soul] which knows universals separated from matter, from which they say it follows that it is not bound to matter, if it can admit those very things into itself; [the soul] which receives knowledge in an indivisible manner, exalted above matter and above all corporeal substance, by which means it is judged to be immaterial and incorporeal, entirely beyond all controversy; [the soul] which relies on itself and its own nature, not depending on the mass or support of the body.

In addition to these, if the soul were not immortal, man would be the most wretched of all living creatures. Furthermore, the natural appetite—extended not toward the present age, but toward all ages alike and even toward eternity itself, sought and desired—would plainly have been implanted in man in vain and to no purpose if he lacked the immortality which he desires. Nor would the Good itself, the source of all good, be sought by it with such zeal, as if by a restless will, if it had not exceeded the limits of a mortal and transitory nature; [a soul] which can suffer no contrary action from which corruption might arise.

It is also most well-known that there resides in the soul itself the fact that it receives and knows within itself all things which are otherwise contrary; and it is of such a simple and indivisible nature that it can be abolished neither through itself nor by accident. Nor can death loom over it, whether from its own essence or from the nature of its subject—upon which, clearly, it does not depend—since indeed it does not depend on the body which it informs, and to which it bestows motion, life, and sense. Rather, it is life, which by its own innate character...