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.

Against my will, in the course of my travels, the belief that everything worth knowing was known at Cambridge gradually wore off. In this respect my travels were very useful to me.

Dr. Arnold . . . the admired reformer of public schools, came across some cranks who thought it a mistake to flog boys. Anyone reading his outburst of furious indignation against this opinion will be forced to the conclusion that he enjoyed inflicting floggings.

Each act of cruelty is eternally a part of the universe; nothing that happens later can make that act good rather than bad, or can confer perfection on the whole of which it is a part.

3 is prime, 5 is prime, 7 is prime, 9 is a paradox; as is a paradox why the number 1 is not prime if it has no other divisors besides himself.

I think it would be just to say the most essential characteristic of mind is memory, using this word in its broadest sense to include every influence of past experience on present reactions.

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.