It does not matter how many tumbles you have in this life, so long as you do not get dirty when you tumble; it is only the people who have to stop to be washed and made clean, who must necessarily lose the race. And I can assure you that there is the greatest practical benefit in making a few failures early in life. You learn that which is of inestimable importance

Friendship involves many things but, above all the power of going outside oneself and appreciating what is noble and loving in another.

Mathematics may be compared to a mill of exquisite workmanship, which grinds you stuff of any degree of fineness; but, nevertheless, what you get out depends upon what you put in; and as the grandest mill in the world will not extract wheat-flour from peascods, so pages of formulae will not get a definite result out of loose data.

Of moral purpose I see no trace in Nature. That is an article of exclusively human manufacture and very much to our credit.

Agnosticism simply means that a man shall not say that he knows or believes that for which he has no grounds for professing to believe.

Better live a crossing-sweeper than die and be made to talk twaddle by a "medium" hired at a guinea a seance.

Common sense is science exactly in so far as it fulfills the ideal of common sense; that is, sees facts as they are, or at any rate, without the distortion of prejudice, and reasons from them in accordance with the dictates of sound judgment. And science is simply common sense at its best, that is, rigidly accurate in observation, and merciless to fallacy in logic.