 And yet, Kant could not rest with this radical view given his commitments in moral philosophy. Practical reason, and in particular the idea that the moral law does not depend on the qualities of humans as sensuous beings, but only on reason, demands a return to the assumption that the thing-in-itself exists (1877: 262). In the fourth phase, Kant thus reintroduces the thing-in-itself, while maintaining his anti-psychologism.