I wrote because I could not help it. There was something that I wanted to say, and I said it: that was all. The fame and the money and the usefulness might or might not follow. It was not by my endeavor if they did.

I would not exchange my freedom from old superstition, if I were to be burned at the stake next month, for all the peace and quiet of orthodoxy, if I must take the orthodoxy with peace and quiet.

It is hard to tell which is worse; the wide diffusion of things that are not true, or the suppression of things that are true.

There is no theory of a God, of an author of Nature, of an origin of the Universe, which is not utterly repugnant to my faculties. . .

Religion is a temper, not a pursuit. It is the moral atmosphere in which human beings are to live and move. Men do not live to breathe: they breathe to live.

it is the worst humiliation and grievance of the suffering, that they cause suffering.

Moral excellence has no regard to classes and professions.