This chapter traces the development of Kant’s thought about teleology. In The Only Possible Premise for a Demonstration of the Existence of God, Kant rejects the classical ontological and cosmological arguments for the existence of God, but proposes his own argument that the existence of God is necessary as the ground of all (other) possibility in the world. He then argues that although explanation in the world should be mechanical explanation, without reference to miraculous, divine interventions, we can nevertheless see nature as an expression of divine intent, or the means through which divine ends are attained. By the time of the Critique of the Power of Judgment, Kant has changed the key of teleology from constitutive to regulative, and argues first for the heuristic use of teleological judgment in natural science but, second, for the recognition of the full realization of human morality, in the form of freedom and the highest good, as the “final end” of the world. He still thinks it rational to believe in the existence of a theoretically indemonstrable God as the ground of the possibility of such an end, but the end is to be defined in human terms and achieved through human efforts.