The conceptual unity of humanity and nature had been a central theme in Marx and Engels’s thought from the early stages of their careers, and was especially prevalent in their discourses on species-being. For instance, in the Economic and Philosophical Manuscripts of 1844, Marx had written, “Man lives from nature, i.e., nature is his body, and he must maintain a continuing dialogue with it if he is not to die. To say that man’s physical and mental life is linked to nature simply means that nature is linked to itself, for man is a part of nature.”[2]