In the previous chapter we attempted to clarify the topology of Deleuze's philosophy. Deleuze's work is but a relentless interpretation of other philosophers and writers; yet, we cannot help but read these interpretations as positing an original ‘Deleuzian philosophy’, and indeed we have seen that this interpretive hunch is fully validated.

This realisation we derived from a careful analysis of Deleuze's preferred mode of speech, the free indirect discourse. In undertaking the history of philosophy, Deleuze aims to sketch out the plane (which he called the ‘plane of immanence’) upon which the thought of the philosopher under consideration resides, and examine the network of concepts to be found there. For this it is not enough to restate what the philosopher has already said, since the philosopher's thought stretches beyond the level of his or her consciousness. The history of philosophy must rather burrow further, to reach the implicit assumptions of the expressly articulated content, or what Deleuze calls the ‘image of thought’. Free indirect discourse, which plays on the undecidability between the theorist and the theorised, was deployed for this purpose.

We remember that Deleuze defined philosophy as the ‘creation of concepts’; but no concept is ever created in a vacuum. A new concept is created only when a new problem is discovered, and a new problem is in turn only discovered when an existing problem is criticised. In short, as we have seen, ‘[i]n philosophy the question and the critique of the question are one’ (ES, 106/119). To attain the ‘image of thought’ is to come face to face with the originary problem which motivated a given philosophy. And when one has successfully critiqued this problem, thereby positing a new problem of one's own, this is when the conditions are ripe for new concepts to be created as a response to this new problem. It is clear that the use of free indirect discourse in this way follows inexorably from Deleuze's philosophical vision.

With preparatory work complete, and armed with an understanding of both the ‘where’ and ‘how’ of Deleuzian philosophy, we must now move on to the question of ‘what’. Using free indirect discourse, Deleuze discussed a plethora of philosophers. What problems did he discover in the process, or equivalently, what problems did he criticise in the process?