In science, as in art, and, as I believe, in every other sphere of human activity, there may be wisdom in a multitude of counsellors, but it is only in one or two of them.
The scientific imagination always restrains itself within the limits of probability.
Of moral purpose I see no trace in Nature. That is an article of exclusively human manufacture and very much to our credit.
The only question which any wise man can ask himself, and which any honest man will ask himself, is whether a doctrine is true or false.
I protest that if some great Power would agree to make me always think what is true and do what is right, on condition of being turned into a sort of clock and would up every morning before I got out of bed, I should instantly close with the offer.
It is because the body is a machine that education is possible. Education is the formation of habits, a superinducing of an artificial organization upon the natural organization of the body.