"La Ciencia en ningún momento está totalmente en lo cierto, pero rara vez está completamente equivocada y tiene en general mayores posibilidades de estar en lo cierto que las teorías no científicas."
"Remember your humanity, and forget the rest."
"The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts."
"There lies before us, if we choose, continual progress in happiness, knowledge and wisdom. Shall we instead choose death, because we cannot forget our quarrels? I appeal as a human being to human beings; remember your humanity, and forget the rest."
"Those who have never known the deep intimacy and the intense companionship of mutual love have missed the best thing that life has to give."
"To fear love is to fear life, and those who fear life are already three parts dead."