Marx's Theses on Feuerbach state his epistemology . That is a Hegelian negation of Feuerbach's negation of Hegel. The First Thesis specifically mentions idealism . The Second Thesis is based on Hegel's critique of Kant: the truth is knowable through practice .

Althusser does not take account that Marx's concept of human nature is a Hegelian sublation of Feuerbach's atheist negation of Hegel's Christianity.