The Republic · Rep. 602e

But were we not saying that such a contradiction is impossible—the same faculty cannot have contrary opinions at the same time about the same thing?

Plato · translated by Benjamin Jowett · composite transcription based on the 1888 third edition
Benjamin Jowett, revised third edition (1888), with Stephanus numbering from the 1908 edition; composite transcription, Project Gutenberg #55201
Passage preview. Read in context for the complete text, notes and references.