I did not, however, commit suicide, because I wished to know more of mathematics.

The skill of the politician consists in guessing what people can be brought to think advantageous to themselves; the skill of the expert consists in calculating what really is advantageous, provided people can be brought to think so.

Science may set limits to knowledge, but should not set limits to imagination.

Are you never afraid of God's judgement in denying him? Most certainly not. I also deny Zeus and Jupiter and Odin and Brahma, but this causes me no qualms. I observe that a very large portion of the human race does not believe in God and suffers no visible punishment in consequence. And if there were a God, I think it very unlikely that He would have such an uneasy vanity as to be offended by those who doubt His existence.

It is in our hearts that evil lies, and it is from our hearts that it must be plucked out.

Ever since men became capable of free speculation, their actions, in innumerable important respects, have depended upon their theories as to the world and human life, as to what is good and what is evil. This is true in the present day as at any former time. To understand an age or a nation, we must understand its philosophy, and to understand its philosophy we must ourselves be in some degree philosophers. There is here a reciprocal causation: the circumstances of men s lives do much to determine their philosophy, but, conversely, their philosophy does much to determine their circumstances.

We know very little, and yet it is astonishing that we know so much, and still more astonishing that so little knowledge can give us so much power.