A new and valid idea is worth more than a regiment and fewer men can furnish the former than command the latter.

It is mere childishness to expect men to believe as their fathers did; that is, if they have any minds of their own. The world is a whole generation older and wiser than when the father was of his son's age.

Our morality seems to be only a check on the ultimate domination of force, just as our politeness is a check on the impulse of every pig to put his feet in the trough.

Deep-seated preferences cannot be argued about - you cannot argue a man into liking a glass of beer.

I dare say that I have worked off my fundamental formula on you that the chief end of man is to frame general propositions and that no general proposition is worth a damn.

It is better for all the world, if instead of waiting to execute degenerate offspring for crime or to let them starve for their imbecility, society can prevent those who are manifestly unfit from continuing their kind. The principle that sustains compulsory vaccination is broad enough to cover cutting the fallopian tubes. Three generations of imbeciles are enough.

I think it not improbable that man, like the grub that prepares a chamber for the winged thing it never has seen but is to be - that man may have cosmic destinies that he does not understand.