The Republic: Soul, City, and Justice

Plato's epistemology holds that learning is really a form of recollection, anamnesis, since the soul possessed knowledge of the Forms before its embodiment and merely needs to be reminded of it. In the Meno, Socrates elicits a correct geometrical proof from an uneducated slave boy through careful questioning alone, taking this as evidence that the boy was not taught the truth but recovered it from within; the Phaedo develops the same idea into a formal argument for the soul's pre-existence, since our idea of perfect equality, for instance, cannot have been derived from the always-imperfect equal objects we perceive.