Whoever wishes to become a philosopher must learn not to be frightened by absurdities.

Nothing of importance is ever achieved without discipline. I feel myself sometimes not wholly in sympathy with some modern educational theorists, because I think that they underestimate the part that discipline plays. But the discipline you have in your life should be one determined by your own desires and your own needs, not put upon you by society or authority.

Almost everything that distinguishes the modern world from earlier centuries is attributable to science, which achieved its most spectacular triumphs in the seventeenth century.

I did not know I loved you until I heard myself telling so, for one instance I thought, "Good God, what have I said?" and then I knew it was true.

Many a man will have the courage to die gallantly, but will not have the courage to say, or even to think, that the cause for which he is asked to die is an unworthy one.

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.

At all times, except when a monarch could enforce his will, war has been facilitated by the fact that vigorous males, confident of victory, enjoyed it, while their females admired them for their prowess.