Rereading Kant on immortality and the highest good

Kant's argument for belief in the immortality of the soul appears tenuous. The standard interpretation suggests that immortality is necessary because agents need an endless time in order to become holy (i.e., incapable of deviation from the moral law). Yet Kant elsewhere argues that sensible beings cannot be holy. This interpretation thus cannot make sense of Kant's insistence that agents become holy, supposing instead that this is an error on Kant's part. Against this reading, I argue that progress toward holiness is simply a definition of virtue, and that Kant's reference to it does not contradict itself by implying that sensible beings must become holy at some point in time. Drawing on Kant's account of the Gesinnung in the Religion, I then proceed to offer a novel reading as to why immortality is needed to secure the complete conformity of a disposition with the moral law.