In the previous chapter we saw how Maimon took Kant's transcendental philosophy in a radically new direction with his notion of differential Ideas of the understanding which serve to explain the genesis of real experience. We then saw how Deleuze reconstructed Maimon's Ideas of the understanding as virtual Ideas belonging to an intersubjective differential unconscious. In this chapter we will continue our examination of Deleuze's theory of Ideas by means of a closer analysis of the Kantian theory; in particular we will see the importance to Deleuze of Kant's characterisation of Ideas as problems. We will also see how Maimon's freeing of Ideas from exclusively belonging to the faculty of reason is taken further in Deleuze's notion of Ideas that ‘occur throughout the faculties and concern them all’ (DR 193/249).

It is important to note that Deleuze uses the notion of ‘faculty’ in a different sense than it has traditionally been used in philosophy. First of all, he not only refers to sensibility, imagination, memory, understanding and reason, but also to what he calls a faculty of speech, a faculty of ‘sociability’, a faculty of ‘vitality’, and he leaves open the possibility ‘for faculties yet to be discovered, whose existence is not yet suspected’ (DR 143/186–7). In the second place, Deleuze argues that faculties are not given ready-made, but emerge and develop with the Ideas or problems they encounter.