Human life, its growth, its hopes, fears, loves, et cetera, are the result of accidents

A hallucination is a fact, not an error; what is erroneous is a judgment based upon it.

Is a man what he seems to the astronomer, a tiny lump of impure carbon and water crawling impotently on a small and unimportant planet? Or is he what he appears to Hamlet? Is he perhaps both as once?

In considering irregular appearances, there are certain very natural mistakes which must be avoided.

There can't be a practical reason for believing something that is not true.

Obviousness is always the enemy of correctness.

The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of the highest excellence, is to be found in mathematics as surely as poetry.