I wish to propose for the reader's favourable consideration a doctrine which may, I fear, appear wildly paradoxical and subversive. The doctrine in question is this: that it is undesirable to believe a proposition when there is no ground whatever for supposing it true.

All that passes for knowledge can be arranged in a hierarchy of degrees of certainty, with arithmetic and the facts of perception at the top.

This has been my life. I have found it worth living, and would gladly live it again if the second chance were offered me.

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.

I had supposed until that time that it was quite common for parents to love their children, but the war persuaded me that it is a rare exception. I had supposed that most people liked money better than almost anything else, but I discovered that they liked destruction even better. I had supposed that intellectuals frequently loved truth, but I found here again that not ten per cent of them prefer truth to popularity.

Thinking you know when in fact you don't is a fatal mistake, to which we are all prone

Americans need rest, but do not know it.