In The Architectonic of Reason, Lea Ypi provides an illuminating and innovative interpretation of the Architectonic in the first Critique. Ypi argues that Kant’s project of uniting practical and theoretical uses of reason in a critical metaphysics ultimately fails because practical reason does not have its own domain in which to legislate. This article challenges Ypi’s objection to practical reason’s lack of a domain in the first Critique. Its main contention is that reason’s need for unity in legislation may be satisfied by a belief in God as a necessary practical presupposition rather than a dogmatic metaphysical reality.
