Kant's philosophy of history, due to its dualistic stance, has never been able to overcome the contradictions between historical inevitability and human freedom, the nonsocial and social nature of human beings, and civil constitutionalism and human morality. The ontological revolution embodied in Marxs concept of activity or practice not only opens up a new perspective on the nature of the world, but also bridges the logical gap between phenomenon and ontology, nature and freedom, and sensibility and rationality. Marxs philosophical thinking not only brings a comprehensive ontological focus to the triple contradictions in Kants philosophy of history, but also makes authentic historical materialist responses to the unity of historical laws and humans free behavior, emotional pursuit and moral progress, and external legal rights and social historical development.