Psychē

Psychē (ψυχή) is the Greek word for soul, and its earliest meaning is breath — the breath of life that animates a living body and departs from it at death. It is connected with the verb psychō, 'to breathe' or 'to blow', much as the Latin anima ('soul') is bound up with breath and wind. In Homer the psyche is the faint shade that flits down to the house of Hades when a man dies, a pale ghost of the living person.

Greek philosophy transformed this breath-soul into the principle of life and mind. For Plato the psyche is immortal, pre-existent, and akin to the divine Forms; he argues for its immortality in the Phaedo, divides it into three parts in the Republic, and pictures its fall and ascent in the winged chariot of the Phaedrus. The soul, not the body, is the true self, and its care is the whole point of philosophy. Aristotle, in his treatise On the Soul, defined the psyche more naturalistically as the form or first actuality of a living body — that which makes a thing alive.

In Neoplatonism Soul (Psychē) is one of the three great hypostases, proceeding from Intellect and mediating between the intelligible and material worlds, and individual souls share in its double life. Across the whole tradition the soul is the traveler whose descent into body and ascent back toward its source — through many lives, by way of purification and recollection — is the great story philosophy has to tell.

Its parts and its journey

The Republic divides the soul into reason, spirited temper, and appetite, justice being their right order. The Phaedo and Phaedrus argue its immortality — it is what moves itself, and so cannot cease to move — while the Timaeus sets a World-Soul between the eternal and the changing. The Neoplatonists added the daring claim that the highest soul never fully descends, keeping one foot in the intelligible world.