If there is anything in the world which I do firmly believe in, it is the universal validity of the law of causation.

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

If a man cannot do brain work without stimulants of any kind, he had better turn to hand work it is an indication on Nature's part that she did not mean him to be a head worker.

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.

If individuality has no play, society does not advance; if individuality breaks out of all bounds, society perishes.

There is no absurdity in theology so great that you cannot parallel it by a greater absurdity in Nature.

Unfortunately, it is much easier to shut one's eyes to good than to evil. Pain and sorrow knock at our doors more loudly than pleasure and happiness; and the prints of their heavy footsteps are less easily effaced.