Who ever heard a theologian preface his creed, or a politician conclude his speech with an estimate of the probable error of his opinion?

A habit of finding pleasure in thought rather than action is a safeguard against unwisdom and excessive love of power, a means of preserving serenity in misfortune and peace of mind among worries. A life confined to what is personal is likely, sooner or later, to become unbearably painful; it is only by windows into a larger and less fretful cosmos that the more tragic parts of life become endurable.

But as the work proceeded I was continually reminded of the fable about the elephant and the tortoise. Having constructed an elephant upon which the mathematical world could rest, I found the elephant tottering, and proceeded to construct a tortoise to keep the elephant from falling. But the tortoise was not more secure than the elephant, and after some twenty years of very arduous toil, I came to the conclusion that there was nothing more that I could do in the way of making mathematical knowledge indubitable.

The raw fruits of the earth were made for human sustenance. Even the white tails of rabbits, according to some theologians, have a purpose, namely to make it easier for sportsmen to shoot them. There are, it is true, some inconveniences: lions and tigers are too fierce, the summer is too hot, and the winter too cold. But these things only began after Adam ate the apple; I before that, all animals were vegetarians, and the season was always spring. If only Adam had been content with peaches and nectarines, grapes and pears and pineapples, these blessings would still be ours.

Philosophy is that part of science which at present people chose to have opinions about, but which they have no knowledge about. Therefore every advance in knowledge robs philosophy of some problems which formerly it had ...and will belong to science.

Freedom comes only to those who no longer ask of life that it shall yield them any of those personal goods that are subject to the mutations of time.

Broadly speaking, Protestants like to be good and have invented theology in order to keep themselves so, whereas Catholics like to be bad and have invented theology in order to keep their neighbors good. Hence, the social character of Catholicism and the individual character of Protestantism.