"The proper study of mankind is man."

"The last thing one discovers in writing a book is what to put first."

"If we submit everything to reason, our religion will have nothing in it mysterious or supernatural."

"Man is equally incapable of seeing the nothingness from which he emerges and the infinity in which he is engulfed."

"The strength of a man's virtue should not be measured by his special efforts, but by his ordinary doing."