This essay will freely draw inspiration from Nietzsche's thought (focused on Zarathustra, an artwork often set aside in ethics arguments), in order to build a definition of the perspective as a first step to ethic of authenticity, starting by enumerating what a perspective is not. How can we prove the existence of a substance which will be independent of the introspection? How can we be sure that this judgment is not a kind of illusion of our own mind? Most of the philosophers, according to Nietzsche, have been tempted by a retirement in a place that he calls a "desert," what we would probably called probably today some "realism of value." It seems to be an epistemic problem: philosophy attempts to build a system or, perhaps with more humility, tries to resolve fundamental antinomies of the existence or reality we can objectively reach by creating a closed system which can explain intellectually the reality with fundamental concepts.