No delusion is greater than the notion that method and industry can make up for lack of mother-wit, either in science or in practical life.

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

As a natural process, of the same character as the development of a tree from its seed, or of a fowl from its egg, evolution excludes creation and all other kinds of supernatural intervention.

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.

Books are the money of Literature, but only the counters of Science.

The besetting sin of able men is impatience of contradiction and of criticism. Even those who do their best to resist the temptation, yield to it almost unconsciously and become the tools of toadies and flatterers. "Authorities," "disciples," and "schools" are the curse of science and do more to interfere with the work of the scientific spirit than all its enemies.

'Infidel' is a term of reproach, which Christians and Mohammedans, in their modesty, agree to apply to those who differ from them.