else it could never have had any thorough consistency, even from the beginning. For things that are subject to corruption are corrupted by contraries: wherefore everything that is corrupted is subject to dissolution; and what is subject to dissolution is compound; and what is compound is of many parts; and what is made up of parts manifestly is made up of diverse parts; and the diverse is not the identical: consequently the soul, being simple, and not being made up of diverse parts, but being uncompound and indissoluble, must be, in virtue of that, incorruptible and immortal.
Besides, everything that is put in action by something else, and does not possess the principle of life in itself, but gets it from that which puts it in action, endures just so long as it is held by the power that operates in it; and whenever the operative power ceases, that also comes to a stand which has its capacity of action from it. But the soul, being self-acting, has no cessation of its being. For it follows, that what is self-acting is ever-acting; and what is ever-acting is unceasing; and what is unceasing is without end; and what is without end is incorruptible; and what is incorruptible is immortal. Consequently, if the soul is self-acting, as has been shown above, it follows that it is incorruptible and immortal, in accordance with the mode of reasoning already expressed.
And further, everything that is not corrupted by the evil proper to itself, is incorruptible; and the evil is opposed to the good, and is consequently its corrupter. For the evil of the body is nothing else than suffering, and disease, and death; just as, on the other hand, its excellency is beauty, life, health, and vigour. If, therefore, the soul is not corrupted by the evil proper to itself, and the evil of the soul is cowardice, intemperance, envy, and the like, and all these things do not despoil it of its powers of life and action, it follows that it is immortal.