Divided into —Old, the philosophic teaching of Plato and his immediate followers; Middle, a modification of the Platonic system, taught by Arcesilaos; New, the half-sceptical school of Carneades.
Plato taught that matter is eternal and infinite, but without form or order; and that there is an intelligent cause, the author of everything. He maintained that we could grasp truth only so far as we had elevated our mind by thought to its divine essence.
Arcesilaos was the great antagonist of the Stoics, and wholly denied man's capacity for grasping truth.
Carneades maintained that neither our senses nor our understanding could supply us with a sure criterion of truth.
The talent of the Academy
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894