"The fundamental error of all systems of morality is that they are not based on observation."

"A last trick is to become personal, insulting and rude as soon as you perceive that your opponent has the upper hand. In becoming personal you leave the subject altogether, and turn your attack on the…"

"The greatest happiness is to be born, and the least to die."

"The first forty years of life give us the text; the next thirty supply the commentary."

"The less a man is burdened by his own will, the more he is capable of objective knowledge."