Nietzsche sought a new sort of aristocracy of super- or above-men, which would be the ultimate goal of civilized existence. The sources of this Nietzschean idea were several. Darwin's theory of evolution suggested to Nietzsche the notion of humanity as an evolving species, although Nietzsche emphatically rejected the concept of the superman or above-man as the outcome of a biological process; in a sense, the superman or above-man is a spiritualized form of Darwinism.