Full Idea
We are convinced that if we are ever to have pure knowledge of anything, we must get rid of the body and contemplate things by themselves with the soul by itself.
Gist of Idea
To achieve pure knowledge, we must get rid of the body and contemplate things with the soul
Source
Plato (Phaedo [c.374 BCE], 066c)
Book Reference
Plato: 'The Last Days of Socrates', ed/tr. Tredennick,Hugh [Penguin 1969], p.111
A Reaction
This seems to be the original ideal which motivates the devotion to a priori knowledge - that it will lead to a 'pure' knowledge, which in Plato's case will be eternal and necessary knowledge, like taking lessons from the gods. Wrong.