"Training is principally an act of faith. The athlete must believe in its efficacy; he must believe that through training he will become fitter and stronger; that by constant repetition of the same movements he will become more skilful and his muscles more relaxed...He must be a fanatic for hard work and enthusiastic enough to enjoy it."

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I should attempt to treat human vice and folly geometrically... the passions of hatred, anger, envy, and so on, considered in themselves, follow from the necessity and efficacy of nature... I shall, therefore, treat the nature and strength of the emotion in exactly the same manner, as though I were concerned with lines, planes, and solids.

— Baruch Spinoza