Marx's theory of human nature
In his works, Karl Marx does not refer to "human nature" as such, but to Gattungswesen, which is generally translated as "species-being" or "species-essence". According to a note from Marx in the Manuscripts of 1844, the term is derived from Ludwig Feuerbach's philosophy, in which it refers both to the nature of each human and of humanity as a whole.
Source: Wikipedia — Marx's theory of human nature (CC BY-SA 4.0)