...All instincts which are not discharged to the outside are turned back inside—this is what I call the internalization [Verinnerlichung] of man. From this first grows in man what people later call his “soul.” The entire inner world, originally as thin as if stretched between two layers of skin, expanded and extended itself, acquired depth, width, and height, to the extent that what a person discharged out into the world was obstructed. Those frightening fortifications with which the organization of the state protected itself against the old instincts for freedom—punishments belong above all to these fortifications—brought it about that all those instincts of the wild, free, roaming man turned themselves backwards, against man himself. Enmity, cruelty, joy in pursuit, in attack, in change, in destruction—all those turned themselves against the possessors of such instincts. That is the origin of “bad conscience.” The man who, because of a lack of external enemies and opposition, was forced into an oppressive narrowness and regularity of custom impatiently tore himself apart, persecuted himself, gnawed away at himself, grew upset, and did himself damage—this animal which scraped itself raw against the bars of its cage, which people want to “tame,” this impoverished creature, consumed with longing for the wild, which had to create out of its own self an adventure, a torture chamber, an uncertain and dangerous wilderness—this fool, this yearning and puzzled prisoner, became the inventor of “bad conscience.” But with him was introduced the greatest and weirdest illness, from which humanity up to the present time has not recovered, the suffering of man from man, from himself, a consequence of the forcible separation from his animal past, a leap and, so to speak, a fall into new situations and living conditions, a declaration of war against the old instincts, on which, up to that point, his power, joy, and ability to inspire fear had been based. Let us at once add that, on the other hand, the fact that there was on earth an animal soul turned against itself, taking sides against itself, meant there was something so new, profound, unheard of, enigmatic, contradictory, and full of the future, that with it the picture of the earth was fundamentally changed. In fact, it required divine spectators to appreciate the dramatic performance which then began and whose conclusion is by no means yet in sight—a spectacle too fine, too wonderful, too paradoxical, to be allowed to play itself out senselessly and unobserved on some ridiculous star or other! Since then man has been included among the most unexpected and most thrillingly lucky rolls of the dice in the game played by Heraclitus’ “great child,” whether he’s called Zeus or chance.* For himself he arouses a certain interest, a tension, a hope, almost a certainty, as if something is announcing itself with him, something is preparing itself, as if the human being were not the goal but only a way, an episode, a bridge, a great promise . . .--Nietzsche, "Genealogy of Morals"