This research main objective is to expose some perspectivist articulation of knowledge, it’s epistemological and ethical implications of Nietzsche’s late period thinking from a genealogical point of view. We shall demonstrate the process of rationality, it’s dynamics from the regulative fictions notion and the author’s criticism about the psychology of the error, based on his description of reactive feelings. So we’re explaining how Nietzsche articulate this critics in order to, later on, achieve his philosophical emancipation. We will also explore some aspects of Kant’s moral psychology and some nuances of the description of moral feelings by Rée in order to present Nietzsche’s psychology itself and its protagonism to the creation...