Is there any place for morality and normative ethics in Marx's ideas? The attempt to answer this question has generated a long debate and a large number of studies. Most of them agree that Marx is ambiguous at this point because he oscillates between science and normativity. But the reasons for this contradictory attitude have not been clearly identified. A distinction between practical materialism and historical materialism, as two different theories that coexist in Marx's work, can be an effective way to address the problem. While the former is inherently ethical, the scientism of the latter can hardly be associated with morality. Young Marx's practical materialism becomes subordinated to mature Marx's historical materialism, but never di...