Now with animals of all kinds, the acquirement of almost all their pleasures, with the exception of those of warmth and rest, are associated, and have long been associated with active movements, as in the hunting or search for food, and in their courtship. Moreover, the mere exertion of the muscles after long rest or confinement is in itself a pleasure, as we ourselves feel, and as we see in the play of young animals. Therefore on this latter principle alone we might expect, that vivid pleasure would be apt to show itself conversely in muscular movements. I cannot believe that our muscular vigor will ever be a superfluity. Even if the day ever dawns in which it will not be needed for fighting the old heavy battles against Nature, it will always be needed to furnish the background of sanity, serenity and cheerfulness to life, to give moral elasticity to our disposition, to round off the wiry edge of our fretfulness, and make us good humored and easy of approach.
Weakness is too apt too be what doctors call irritable weakness.
And that blessed internal peace and confidence, that acquiescentia in seipso, as Spinoza used to call it, that wells up from every part of the body of a muscularly well trained human being, and soaks the indwelling soul of him with satisfaction, is, quite apart from every consideration of its mechanical utility, an element of spiritual hygiene of supreme significance. But it is not always the material size of a thing that measures its importance, often it is its place and function. One of the most philosophical remarks I ever heard was by an unlettered workman who was doing some repairs at my house many years ago. But what little there is , is very important. And the remark certainly applies to this case.