according to certain rules, and those rules have excluded these values from the outset. The life-insurance actuary may, for his purposes, neglect many things about men, and yet calculate, quite correctly, what percentage of them will die at forty. But he has not proved that the qualities he has neglected do not exist simply because they do not come in to upset his calculations. A politician finds that he has to base his calculations on quite different aspects of mankind from those found satisfactory by the actuary. In the same way, a mountain is a different thing to a poet from what it is to a man of science. For the kind of understanding of the universe that the man of science is after, the mountain is merely a heap of certain kinds of matter weighing so many millions of tons. The poet, who is after a different kind of vision, finds it necessary to take into account quite other factors which enter into his total experience of the mountain. The scientist may also experience emotions of awe and reverence in the presence of the mountain, but for the purposes of his science these factors of his experience may be neglected. He _abstracts_ from the total concrete fact of his experience of the mountain. The mountain, as he describes it in the scientific paper he proceeds to write, is a mere pale shadow of the real mountain; he probably leaves it indistinguishable from any other mountain that happens to weigh the same, just as to the life-insurance actuary all men of forty are exactly alike. If we believe that the factors in experience that the scientific man neglects are quite as real as those he takes into account, it becomes a matter for wonder that science is possible. How is it that science forms a closed system――that nothing from the worlds it neglects ever comes in to disturb it?