The unexamined life is not worth living for men.
Plato, Apology 38a, tr. G. M. A. Grube
It would be better for me that multitudes of men should disagree with me rather than that I, being one, should be out of harmony with myself.
Anyone who holds a true opinion without understanding is like a blind man on the right road.
There is no greater evil one can suffer than to hate reasonable discourse.
How many things I have no need of!
Quoted in Diogenes Laertius, Lives of Eminent Philosophers, II
Those who want fewest things are nearest to the Gods.
Quoted in Diogenes Laertius, Lives of Eminent Philosophers, II