“Know thyself.”

“To know thyself is the beginning of wisdom.”

“My friend...care for your psyche...know thyself, for once we know ourselves, we may learn how to care for ourselves" -Socrates”

“I know I'm intelligent because I know that I know nothing.”

“I know that I am intelligent, because I know that I know nothing.”

“I only know that I know nothing”

“Well, although I do not suppose that either of us know anything really beautiful & good, I am better off than he is- for he knows nothing & thinks that he knows; I neither know nor think that I know.”