The Will to Power · Friedrich Wilhelm Nietzsche
703.
Pain has been confounded with one of its subdivisions, which is exhaustion: the latter does indeed represent a profound reduction and lowering of the will to power, a material loss of strength--that is to say, there is _(a)_ pain as the stimulus to an increase or power, and _(b)_ pain following upon an expenditure of power; in the first case it is a spur, in the second it is the outcome of excessive spurring.... The inability to resist is proper to the latter form of pain: the provocation of that which resists is proper to the former.... The only happiness which is to be felt in the state of exhaustion is that of going to sleep; in the other case, happiness means triumph.... The great confusion of psychologists consisted in the fact that they did not keep these two kinds of happiness--that of falling asleep, and that of triumph--sufficiently apart. Exhausted people will have repose, slackened limbs, peace and quiet--and these things constitute the bliss of Nihilistic religions and philosophies, the wealthy in vital strength, the active, want triumph, defeated opponents, and the extension of their feeling of power over ever wider regions. Every healthy function of the organism has this need,--and the whole organism constitutes an intricate complexity of systems struggling for the increase of the feeling of power....
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