The twin conceptions of sin and vindictive punishment seem to be at the root of much that is most vigorous, both in religion and politics.

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

The solution of the difficulties which formerly surrounded the mathematical infinite is probably the greatest achievement of which our age has to boast.

Do not use power to suppress opinions you think pernicious, for if you do the opinions will suppress you.

[There are m]oral precepts that we consider really important, such as 'don't pick your nose' or 'don't eat peas with a knife'. There may, for ought I know, be admirable reasons for eating peas with a knife, but . . . early persuasion has made me completely incapable of appreciating them.

To discover a system for the avoidance of war is a vital need of our civilisation.

The first essential character [of civilization], I should say, is forethought. This, indeed, is what mainly distinguishes men from brutes and adults from children.