Lange's interpretation of historical materialism is an improvement upon the official Marxist-Leninist doctrine. He makes some of its concepts less vague and some of its premisses more articulate. But he follows in many respects the traditional speculative and ideological line. In particular, he is as careless as other Marxist-Leninists in his use of language. A modern philosopher would say that Lange does not use language for the purpose of formulating empirically significant possibilities, but with a pictorial intention. He is thus misled into assuming the existence of all kinds of abstract entities, which he regards as "causes' or "forces' responsible for social change.