One must care about a world one will not see.

So long as there is death there will be sorrow, and so long as there is sorrow it can be no part of the duty of human beings to increase its amount, in spite of the fact that a few rare spirits know how to transmute it.

If a man is offered a fact which goes against his instincts, he will scrutinize it closely, and unless the evidence is overwhelming, he will refuse to believe it. If, on the other hand, he is offered something which affords a reason for acting in accordance to his instincts, he will accept it even on the slightest evidence. The origin of myths is explained in this way.

I used often to go to America during Prohibition, and there was far more drunkenness there then than before; the prohibition of pornography has much the same effect.

The military superiority of Europe to Asia is not an eternal law of nature, as we are tempted to think, and our superiority in civilization is a mere delusion.

I am not myself in any degree ashamed of having changed my opinions.

Man can be scientifically manipulated.