Plato, in one of his dialogues (Theœtetus, 155 C–D), says: “ The feeling of wonder is the genuine mark of the philosopher; for philosophy has its origin in wonder.” What Plato here says may be accepted as true: the philosopher does wonder. But the philosopher is not the only man who wonders about things. It might perhaps be going too far to say that all men experience the feeling, for some men seem to plod on their weary round without curiosity enough to wonder at anything, whilst others, being comfortable, are satisfied to take things for granted, and never think of wondering at them.