There are two great rules of life; the one general and the other particular. The first is that everyone can, in the end, get what he wants, if he only tries. That is the general rule. The particular rule is that every individual is, more or less, an exception to the rule.

There are two classes [of scientists], those who want to know, and do not care whether others think they know or not, and those who do not much care about knowing, but care very greatly about being reputed as knowing.

To die completely, a person must not only forget but be forgotten, and he who is not forgotten is not dead.

Nature. As the word is now commonly used it excludes nature's most interesting productions-the works of man. Nature is usually taken to mean mountains, rivers, clouds and undomesticated animals and plants. I am not indifferent to this half of nature, but it interests me much less than the other half.

He was born stupid, and greatly increased his birthright.

Cat-Ideas and Mouse-Ideas. We can never get rid of mouse-ideas completely, they keep turning up again and again, and nibble, nibble-no matter how often we drive them off. The best way to keep them down is to have a few good strong cat-ideas which will embrace them and ensure their not reappearing till they do so in another shape.

Justice is my being allowed to do whatever I like. Injustice is whatever prevents my doing so.