Practical Reason and the Metaphysics of Human Dignity: A Dialogue between Christian Personalists and Kantian Liberalism

This dissertation aims to correct the critical interpretation of Immanuel Kant's metaphysics and ethics developed by Thomistic thinkers as part of their critique of liberal politics, an interpretation that was adopted by Christian personalists such as Karol Wojtyla. According to the Thomistic interpretation, Kant's transcendental idealism negates traditional realistic metaphysics, and consequently the traditional ethics based on the guidance of the human will by the intellect's grasp of the teleological structure of reality or the created order of ends. This implies the construction of a subjectivist, formalist, and proceduralist ethics based on a radical notion of individual autonomy that is at the basis of the modern liberal and secular state. In contrast to this view, which is shared by some influential Neo-Kantian thinkers, this dissertation will argue that Kant is more adequately understood as proposing a different kind of metaphysics, based on the primacy of the practical use of reason. Once cognition is understood to be restricted to objects of possible (theoretical) experience and traditional "dogmatic" metaphysics is rendered impossible, a new sort of metaphysics must be primarily moral and found through the participation of human beings in the moral law as pure practical reason. Thus, in Kant's concept of the unconditionally good will (that grounds the categorical imperative) the idea of duty for duty's sake translates for sensible beings the moral priority of the constitution of the good as an existential participation in the order of being. In this way, teleology is not negated but has its innermost moral ground disclosed. Kant also recovers the moral core of faith in God and in the immortality of the soul, whose characterization as postulates of practical reason points to their metaphysical status beyond the fixities of empirical being rather than to a doubtful claim about their existence. Finally, autonomy of reason, or the self-legislation of morality, is understood as the only proper instantiation in rational beings of an order that is primarily moral and thus not reducible to the attraction of the will by external objects. By choosing autonomously, i.e. morally, human beings display their dignity as participants in a rational, supersensible nature that can ground their political relations on more than mere isolated subjectivity or willfulness.