However, in the sixth Thesis on Feuerbach (1845), Marx criticizes the traditional conception of "human nature" as "species" which incarnates itself in each individual, instead arguing that the conception of human nature is formed by the totality of "social relations". Thus, the whole of human nature is not understood, as in classical idealist philosophy, as permanent and universal: the species-being is always determined in a specific social and historical formation, with some aspects being biological.