Based on his dualistic understanding of the nature of the soul
The physical body is subject to corruption and change- it imprisons the soul (psyche)
Plato regarded the body as a source of endless trouble in its attempt to distract the soul with its fears and desires
The soul is separate from the body and is eternal
The soul is aware of being immaterial though its memories of the eternal world of Forms are blurred
At death, the body perishes but the soul leaves it to return to the world of Forms- in most cases the soul is then reborn into another body, though a few remain in the eternal world
The soul, therefore, is separate from the body but gives it life and directs it