If I steal money from any person, there may be no harm done from the mere transfer of possession; he may not feel the loss, or it may prevent him from using the money badly. But I cannot help doing this great wrong towards Man, that I make myself dishonest.

He who truly believes that which prompts him to an action has looked upon the action to lust after it, he has committed it already in his heart.

To know all about anything is to know how to deal with it under all circumstances.

If a belief is not realized immediately in open deeds, it is stored up for the guidance of the future.

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.

Remember that [scientific thought] is the guide of action; that the truth which it arrives at is not that which we can ideally contemplate without error, but that which we may act upon without fear; and you cannot fail to see that scientific thought is not an accompaniment or condition of human progress, but human progress itself.

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