It seems to us unwise to have insisted on teaching geometry to the younger Dionysius, tyrant of Syracuse, in order to make him a good king, but from Plato's point of view it was essential. He was sufficiently Pythagorean to think that without mathematics no true wisdom is possible.

Humanistic ethics is based on the principle that only humans themselves can determine the criterion for virtue and not an authority transcending us.

Few people can be happy unless they hate some other person, nation, or creed.

Official morality has always been oppressive and negative: it has said "thou shalt not," and has not troubled to investigate the effect of activities not forbidden by the code.

Find more pleasure in intelligent dissent than in passive agreement, for, if you value intelligence as you should, the former implies a deeper agreement than the latter.

Mysticism is, in essence, little more than a certain intensity and depth of feeling in regard to what is believed about the universe.

All movements go too far.