The two understandings of "origin" are neatly identified and contrasted by Foucault in his essay, "Nietzsche, Genealogy, History." The kind of "origin" that Nietzsche criticizes sees origins as moments of creation, when things spring into being. This is the kind of origin we get in the story of Adam and Eve, where humans are spontaneously created. Nietzsche prefers a genealogical kind of origin story, where things have a long and tangled history, slowly developing their present form and meaning. We see this in the evolutionary account of the origin of humans, where a slow chain of mutations leads to our present state. Nietzsche dislikes the former interpretation because it sees the "thing" as being absolute in some way. For instance, in the Adam and Eve myth, "humanity" is seen as a constant: we were created in precisely the shape we have now, and we have always had the same purposes, drives, and wills. Nietzsche argues that one thing can have countless different meanings, and be dominated by countless different drives and wills during its existence. These different meanings and wills promote a gradual genealogy rather than an instantaneous creation.

The knightly-aristocratic code is that of Nietzsche's "blonde beasts" and barbarians. These are people still governed by their animal instincts, who can release their instincts for aggression and cruelty freely and without inhibition. The priestly moral code is developed by powerless people who are no longer able to give free rein to their animal instincts and aggression. Instead, they turn their instincts for aggression inward upon themselves, torturing and struggling against themselves. In so doing, they develop an inner life and a "soul." While there is something very sick about this self-torture, it is what makes humans "interesting" and what separates us from other animals.

Ressentiment is the French word for "resentment." It is the dominant mode of slave morality. The slaves who do not have the power to avenge themselves directly upon the masters who hurt them, instead feel ressentiment toward them. This is the form their hatred for the masters takes. The hatred the masters feel for the slaves is more in the form of contempt. They look down upon the slaves as weak, unhealthy, and undesirable. Ressentiment and contempt differ in three significant ways. First, the ressentiment of the slaves is a powerful and dominant feeling that drives their morality, whereas the contempt of the masters is an afterthought that does not much interest them. Second, ressentiment is what Nietzsche calls a "reactive affect." That is, it is produced in reaction to the behavior of the masters. While the contempt of the masters springs from them spontaneously, the ressentiment of the slaves is in a way governed by the suffering imposed upon them by the masters. Third, ressentiment is used to denote the masters as "evil," whereas contempt is used to denote the slaves only as "bad."