“No doubt,” he said, “you have seen that before. It does not hurt a pinprick. But what does it show? The capacity for pain is not needed in the muscle, and it is not placed there⁠—is but little needed in the skin, and only here and there over the thigh is a spot capable of feeling pain. Pain is simply our intrinsic medical adviser to warn us and stimulate us. Not all living flesh is painful; nor is all nerve, not even all sensory nerve. There’s no taint of pain, real pain, in the sensations of the optic nerve. If you wound the optic nerve, you merely see flashes of light⁠—just as disease of the auditory nerve merely means a humming in our ears. Plants do not feel pain, nor the lower animals; it’s possible that such animals as the starfish and crayfish do not feel pain at all. Then with men, the more intelligent they become, the more intelligently they will see after their own welfare, and the less they will need the goad to keep them out of danger. I never yet heard of a useless thing that was not ground out of existence by evolution sooner or later. Did you? And pain gets needless.