Hatred of enemies is easier and more intense than love of friends. But from men who are more anxious to injure opponents than to benefit the world at large no great good is to be expected.

In the ordinary business of life punctuality is . . . necessary.

Measures of sterilization should, in my opinion, be very definitely confined to persons who are mentally defective

[Industrialism's soon diminishing] capacity to supply human needs could be prevented if men exercised any restraint or foresight in their present frenzied exploitation.

There's a Bible on that shelf there. But I keep it next to Voltaire - poison and antidote.

More cranks take up unfashionable errors than unfashionable truths.

If an opinion contrary to your own makes you angry, that is a sign that you are subsciously aware of having no good reason for thinking as you do. [...] The most savage controversies are those about matters as to which there is no good evidence either way. Persecution is used in theology, not in arithmetic, because in arithmetic there is knowledge, but in theology there is only opinion. So whenever you find yourself getting angry about a difference of opinion, be on your guard; you will probably find, on examination, that your belief is going beyond what the evidence warrants.