Do not fear to be eccentric in opinion, for every opinion now accepted was once eccentric.

Conquer the world by intelligence, and not merely by being slavishly subdued by the terror that comes from it.

The fact that an opinion has been widely held is no evidence whatever that it is not utterly absurd; indeed in view of the silliness of the majority of mankind, a widely spread belief is more likely to be foolish than sensible.

Fear is the main source of superstition, and one of the main sources of cruelty. To conquer fear is the beginning of wisdom, in the pursuit of truth as in the endeavour after a worthy manner of life.

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

One should respect public opinion insofar as is necessary to avoid starvation and keep out of prison, but anything that goes beyond this is voluntary submission to an unnecessary tyranny.