The Universe as we know it is occupied in transmitting energy. The amount seems inexhaustible and indestructible. It rolls on interminably, discharging warmth and light into blank spaces; and, whenever worlds have formed, getting tangled up in a thousand shapes and sputtering mightily as it finds its complicated way out through them. A living creature has an elaborate system of receiving and discharging energy, more elaborate as the life-form grows higher. Force in inorganic matter has a simple channel, varying the monotony by occasional explosions. Force in the vegetable world is freer and learns new tricks—building tall trees and flaming out in blossoms. Force in the animal kingdom has wider range; these life-forms can do more things. They have more ways to express energy, and more ways to receive it. With special senses tuned to catch various vibrations, they respond to light, heat, and sound, to touch, taste, and smell; their impressions are varied and their expressions equally so. Here enters Consciousness, with its extremes of Pleasure and Pain; the director of action, but not its cause. This complex engine, receiving so many impressions, transmitting so many expressions, must feel, because it acts; must act, because it feels. An Action is a consciously directed expression of energy. A Sensation is a consciously recorded impression of energy. Both sensation and action, if normal, are pleasurable—the conscious transmission of energy is joy. The pleasure in sensation increases in proportion to the extent and delicacy of the sensorium. The pleasure in action increases in proportion to the extent and delicacy of the executive mechanism. Pain, of course, is proportionate to pleasure at any stage; meaning only abnormal use of the same nerves, but the higher the development of the organism the greater its ability to avoid pain. The course of evolution has been to develop more and more complicated instruments for the transmission of energy. Society, as the highest life-form, is the most exquisitely complex of all; it has a sensorium far larger, and more subtly sensitive, and an executive apparatus commensurate; it has a degree of consciousness highest of all, and a proportional capacity for joy and ability to avoid pain.