Pure mathematics consists entirely of assertions to the effect that, if such and such a proposition is true of anything, then suchand such another proposition is true of that thing.... Thus mathematics may be defined as the subject in which we never know what we are talking about, nor whether what we are saying is true.

Really high-minded people are indifferent to happiness, especially other people's.

One is often told that it is a very wrong thing to attack religion, because religion makes men virtuous. So I am told; I have not noticed it.

I do not pretend to start with precise questions. I do not think you can start with anything precise. You have to achieve such precision as you can, as you go along.

Although this may seem a paradox, all exact science is dominated by the idea of approximation. When a man tells you that he knows the exact truth about anything, you are safe in inferring that he is an inexact man. Every careful measurement in science is always given with the probable error ... every observer admits that he is likely wrong, and knows about how much wrong he is likely to be.

If everything has a cause, then God must have a cause. If there can be anything without a cause, it may just be the world as God.

In democratic countries, the most important private organizations are economic. Unlike secret societies, they are able to exercise their terrorism without illegality, since they do not threaten to kill their enemies, but only to starve them.