There is an evil which I have seen under the sun, a person wise in his own conceit; and a still greater evil is to charge with the instruction of others a person who is not even aware of his own ignorance. In Defense of His Flight, Oration
This is not a small fault either to consider oneself wise and to refer everything back to one’s own judgment.… Paul addresses this same reproach to the pagan philosophers: “Professing to be wise, they become fools.” This is the reason for their folly. The author of the Proverbs said on his part, “Do you see a man wise in his own eyes? There is more hope for a fool than for him.” Again, it is Paul who gives this advice: “Do not be wise in your own opinion.”
