Plato's theory of ideas is directly linked to his theory of the soul. In part IV of his book “Republic”, Plato conceives man as body and soul. As the body changes and ages, the soul is immutable, eternal and divine.
For Aristotle, men are not the only beings who have souls (or psyches); all living beings have it, from daisies and mollusks to more complex beings. Like a form, a soul is an act of a particular type.
