Round about the accredited and orderly facts of every science there ever floats a sort of dust-cloud of exceptional observations, of occurrences minute and irregular and seldom met with, which it always proves more easy to ignore than to attend to... Anyone will renovate his science who will steadily look after the irregular phenomena, and when science is renewed, its new formulas often have more of the voice of the exceptions in them than of what were supposed to be the rules.

The greatest empiricists among us are only empiricists on reflection: when left to their instincts, they dogmatize like infallible popes.

We are all potentially such sick men. The sanest and best of us are of one clay with lunatics and prison-inmates. And whenever we feel this, such a sense of the vanity of our voluntary career comes over us, that all our morality appears but as a plaster hiding a sore it can never cure, and all our well-doing as the hollowest substitute for that well-being that our lives ought to be grounded in, but alas! are not.

The good we do today becomes the happiness of tomorrow.

When once a decision is reached and execution is the order of the day, dismiss absolutely all responsibility and care about the outcome.

The first thing the intellect does with an object is to class it along with something else. But any object that is infinitely important to us and awakens our devotion feels to us also as if it must be sui generis and unique. Probably a crab would be filled with a sense of personal outrage if it could hear us class it without ado or apology as a crustacean, and thus dispose of it. 'I am no such thing,' it would say; 'I am MYSELF, MYSELF alone.

A winner's attitude: it may be difficult, but it's possible. A loser's attitude: It may be possible, but it's too difficult.