ABSTRACT
At the bottom of all philosophy, of all science and of all thinking, you will find the one all-inclusive question: How is man to tell truth from error ? The ignorant man solves this problem in a very simple manner: he holds that whatever he believes, he knows; and that whatever he knows is true. This is the attitude of all amateur and professional theologians, politicians and other numbskulls of that sort. The pious old maid, for example, who believes in the doctrine of the immaculate conception looks upon her faith as proof, and holds that all who disagree with her will suffer torments in hell. Opposed to this childish theory of knowledge is the chronic doubt of the educated man. He sees daily evidence that many things held to be true by nine-tenths of all men are, in reality, false, and he is thereby apt to acquire a doubt of everything, including his own beliefs.
