This common workaday knowledge of ours seems intuitive to us only because we had so many years during which it was reiterated to us, and not because we were unusually sensitive to impressions. Children often seem almost as stupid as any young animal, and to require long practice before they know their way around in the world, although, once obtained, this common sense is never forgotten. That child is virtuous who acquires all he can of it. This curiosity of childhood makes children the first scientists. They begin, as soon as their eyes are open, dissolving this confused mystery of the world, distinguishing and classifying its parts according to their interests and needs. They push on and on, ever widening the circle, and ever bringing more and more of their experience under the subjugation of their understanding. They begin the process that the scientist completes. As children, after several years we came to know our house and yard, although the attic and cellar were perhaps still dim and fearsome places. Inside the household things were pretty well tabulated and rationalized. It was only when we went outside the gate that we might expect adventures to happen. We should have been very much shocked to see the fire leap from the stove and the bread from the table, as they did in the “Blue Bird,” but in walking down to the village we should not have been surprised to see a giant or a fairy sitting on the green. When we became familiar with the village, the fairies were, of course, banished to remoter regions, until they finally vanished altogether. But it is not so long ago that I lost the last vague vestige of a feeling that there were fairies in England.