Extinguished theologians lie about the cradle of every science, as strangled snakes beside that of Hercules

The best men of the best epochs are simply those who make the fewest blunders and commit the fewest sins.

The child who has been taught to make an accurate elevation, plan, and section of a pint pot has had an admirable training in accuracy of eye and hand.

A world of facts lies outside and beyond the world of words.

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

I hated tobacco. I could have almost lent my support to any institution that had for its object the putting of tobacco smokers to death...I now feel that smoking in moderation is a comfortable and laudable practice, and is productive of good. There is no more harm in a pipe than in a cup of tea. You may poison yourself by drinking too much green tea, and kill yourself by eating too many beefsteaks. For my part, I consider that tobacco, in moderation, is a sweetener and equalizer of the temper.

Mathematics may be compared to a mill of exquisite workmanship, which grinds your stuff to any degree of fineness.