Immortality of the Human Soul
In the Phaedo, a dialogue dedicated to Socrates' last moments. Plato takes on the Pythagorean and Orphic dogma about the immortality of the soul and its reincarnation. Man is compound of a mortal body and an immortal soul. The body is submitted to constant change, whereas the immaterial and eternal soul is by nature akin to the Forms. In his last moments, Socrates appears to be calm and acquainted with his imminent death. For the philosopher, death is not a disaster but the deliverance of the soul from its carnal prison. Philosophy is "training for death" (Phaedo 67de ).
The human soul is eligible to make direct contact with the Forms. Knowledge of the Forms is facilitated when the immortal soul is detached from the bonds of the body; but this condition does not deter the soul from cognizing the Forms even during its course on earth. This acquisition is feasible insofar as the soul refrains from the distractions of the body, and imposes her own rule over it. The veracious knowledge that the soul draws from the Forms is, according to Plato, a sort of "recollection". The incarnated soul recalls to memory the direct sight of the Forms when it preexisted the body. Thus, practicing philosophy consists in the progressive recollection of the soul's obliterated knowledge. Platonic recollection squares with what the philosophers of the West would later name a priori knowledge.
In his posterior dialogue, Republic, Plato will advance unto the division of the human soul into three different and antagonistic parts: the "appetitive" (epithumêtikon) upon which pleasures and desires rest; the "spirited" (thumoeides) upon which affections rests, and the "rational" (logistikon) which is the immortal part of our soul, and accommodates reason and correct judgments. The antithesis between the parts of our soul is more important than that between the soul and the body. Induction into philosophy comes with the authority of the "rational" over the other parts of the soul.