Aristotle maintained that women have fewer teeth than men; although he was twice married, it never occurred to him to verify this statement by examining his wives' mouths.

All the labor of all the ages, all the devotion, all the inspiration, all the noonday brightness of human genius are destined to extinction. So now, my friends, if that is true, and it is true, what is the point?

The luxury to disparage freedom is the privilege of those who already possess it.

A sense of duty is useful in work but offensive in personal relations. People wish to be liked, not to be endured with patient resignation.

Collective fear stimulates herd instinct, and tends to produce ferocity toward those who are not regarded as members of the herd.

The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of the highest excellence, is to be found in mathematics as surely as poetry.

No satisfaction based upon self-deception is solid.