It is a commonplace of Kantian scholarship to describe his system as
an attempt to curb the scope of rationalist metaphysics in order to
accommodate his religio-ethical convictions. Indeed, in the second
edition Preface to the First Critique, Kant himself says bluntly that
he has ‘found it necessary to deny knowledge (Erkenntnis) in order
to make room for faith (Glaube)’.