Thus Spoke Zarathustra

A certain way of valuing things corresponds to life thus weakened. — When, in the Roman Empire, the refinement of the nerves and the slackening of the flesh became rampant, Christianity spread; ever since the spirit of the scholar has weakened the power of the people more and more, democratism has spread. Christianity and democratism spring from one root: from the hatred of everything strong and great, from the suffering that the powerless feel in the face of power. For his state of depression, the Christian, like the democrat, takes revenge in thought on the well-constituted and superior, for example by asserting, in defiance of all evidence, the “equality of all,” or at least striving for it, and the former envisions hell for the outstanding, while the latter envisions their complete elimination.

Nietzsche has, for the first time, seen through the inner essence of Christianity and democratism: they both grow on a morbid, unhealthy, and impoverished soil; both are forms of downward development.

The human being of this downward development, the human being of rancor against everything great, feels in his estimation of man and the world exactly the opposite of the great, strong, self-feeling human being.

The impoverished, the failed, feels the great as evil—and himself as good.

The great, conversely, feels himself as good—and the lowly as bad.

Thus arise two diametrically opposed ways of valuing: the great has the biologically correct way of valuing, that in which ascending life is affirmed; the lowly has the biologically harmful way of valuing, that in which ascending life is denied. The latter morality (“Good—Evil,” seen from below) is the Christian-democratic, the slave-morality;—the former morality (“Good—Bad,” seen from above) is the aristocratic, the master-morality.

Several times and in different lights, Nietzsche has depicted the natural history of both ways of valuing: the first time in "Human, All-Too-Human" I, aphorism 45 (thereby turning against Dr. Paul Rée, who sought the concepts of “good” and “bad” in the manifest sphere of written laws, instead of in the deeper area of instinctive estimation, of biological taste, and of the English-utilitarian, scholarly conception that paid homage to “good—selfless, useful to others,” “bad—selfish, harmful to others,” a conception that is almost purely fiscal, of later origin, and less important for the self-estimation of man and the moral interpretation of existence); then in "Beyond Good and Evil" aphorism 260 (fundamentally, the whole book deals with the difference between those two ways of valuing); furthermore, the first essay in the "Genealogy of Morality," a large part of "Twilight of the Idols," and finally the epilogue in "The Case of Wagner" are devoted to it above all.