  Like Adorno's epistemology, his moral philosophy derives from a materialistic metacritique of German idealism. The model on “Freedom” in Negative Dialectics (ND 211–99) conducts a metacritique of Kant's critique of practical reason. So too, the model on “World Spirit and Natural History” (ND 300–60) provides a metacritique of Hegel's philosophy of history. Both models simultaneously carry out a subterranean debate with the Marxist tradition, and this debate guides Adorno's appropriation of both Kantian and Hegelian “practical philosophy.”