There is no scientific discoverer, no poet, no painter, no musician, who will not tell you that he found ready made his discovery or poem or picture — that it came to him from outside, and that he did not consciously create it from within.

We may always depend on it that algebra, which cannot be translated into good English and sound common sense, is bad algebra.

If a man, holding a belief which he was taught in childhood or persuaded of afterwards, keeps down and pushes away any doubts which arise about it in his mind, purposely avoids the reading of books and the company of men that call in question or discuss it, and regards as impious those questions which cannot easily be asked without disturbing it - the life of that man is one long sin against mankind.

Thought is powerless, except it make something outside of itself: the thought which conquers the world is not contemplative but active.

No simplicity of mind, no obscurity of station, can escape the universal duty of questioning all that we believe.

When an action is once done, it is right or wrong for ever; no accidental failure of its good or evil fruits can possibly alter that.

We feel much happier and more secure when we think we know precisely what to do, no matter what happens, then when we have lost our way and do not know where to turn.