54. Second Group of Problems: The Nature of the Soul. -- Soul and Body. The definition of the soul states exactly its relations to the body: since the soul is the form of the body, it is its intrinsic determining principle. Psychology is not the study of the soul (Plato), but of man composed of body and soul. Not the soul (Plato), but the organism is the seat of the vegetative and sentient vital functions.

Spirituality and Immortality. -- By reason of the functions which it performs without the intrinsic and immediate help of the organism, the intellect (nous) is spiritual; and its immateriality proves its immortality. Aristotle's theory of immortality has been the source of endless controversies among his commentators. It presents serious difficulties owing to the complete separation of the passive intellect from the active. This latter alone is imperishable. But is there question of personal or impersonal immortality? Speaking of the happiness of the future life, the Stagirite compares it to a sort of insensibility; the dead, he says, being incapable of activity. In reality, however, he refrained from hazarding any definite solution of the perplexing problem, and confined himself to merely teaching the survival of the thinking principle. The separation of man from God continues in the future life.