“We must take care of our minds because we cannot benefit from beauty when our brains are missing.”

“We humans seem disastrously in love with this thing (whatever it is) that glitters on the earth— we call it life. We know no other.”

“Question everything. Learn something. Answer nothing.”

“A man's most valuable trait is a judicious sense of what not to believe.”

“Talk sense to a fool and he calls you foolish.”

“A slave is he who cannot speak his thoughts.”

“Real friendship is shown in times of trouble; prosperity is full of friends.”