What we cannot think we cannot think, therefore we also cannot say what we cannot think.

We may often do as we please - but we cannot please as we please.

It is not my prayer and humility that you cause things to go as you wish, but by acquiring a knowledge of natural laws.

Unrestricted nationalism is, in the long run, incompatible with world peace.

Even when the experts all agree, they may well be mistaken.

History is valuable, to begin with, because it is true; and this, though not the whole of its value, is the foundation and condition of all the rest. That all knowledge, as such, is in some degree good, would appear to be at least probable; and the knowledge of every historical fact possesses this element of goodness, even if it posses no other.

Mathematics takes us into the region of absolute necessity, to which not only the actual word, but every possible word, must conform.