I cannot teach anybody anything. I can only make them think

I only know that I know nothing

I know nothing except the fact of my ignorance.

My advice to you is get married: if you find a good wife you’ll be happy; if not, you’ll become a philosopher.

Be kind, for everyone you meet is fighting a hard battle.

Mankind is made of two kinds of people: wise people who know they're fools, and fools who think they are wise.