Kant's teleology of reason and the problem of the highest good

According to Kant’s so-called ‘cosmic’ definition, philosophy is “the science of the relation of all cognition and of all use of reason to the ultimate end (Endzweck) of human reason, to which, as the highest, all other ends are subordinated, and in which they must all unite (KrV, A 839, B 867; 694-695; LJ, 25; 538). As the above definition illustrates, Kant sees the doctrine of the end of reason as answering a question about how the whole of reason – in both its practical and theoretical uses – can be understood as being guided by and fulfilled in a single telos, one that systematizes all of reason’s diverse ends. Accordingly, the unity and integrity of the entire critical enterprise appears to depend upon reason’s need for and capacity to furnish a teleology of its own. Part of what remains unclear, however, is how reason’s final telos, which Kant repeatedly characterizes as practical, succeeds in serving all of reason’s interests, including its theoretical interest in science, or the systematic unity of cognitions. My first aim in this paper is to survey the dominant approaches to this question in the contemporary literature, with a view to evaluating their key strengths and weaknesses. I go on to argue that doing justice to Kant’s teleology of reason requires broader readings of the Highest Good than Kant himself provides. I end by pointing to the Kantian tools and resources which are best suited to helping with this task.