In What is Philosophy?, Deleuze and Guattari make the claim that ‘[i]t may be that believing in this world, in this life, becomes our most difficult task, or the task of a mode of existence still to be discovered on our plane of immanence today. This is the empiricist conversion.’ What are we to make of such a calling? The paper explicates why and in what sense this statement is of exemplary significance both for an appropriate understanding of Deleuze's political (...) thought and for a most timely conceptualisation of politics in a world so clearly defined by immanence, and nothing but immanence. I argue that Deleuze's rigorously constructive approach to the world is not beyond politics, as some recent readings have declared (e.g. those of Badiou and Hallward). Rather, we have to appreciate that in Deleuze and Guattari's demand for a ‘belief in this world’ the political intersects with the dimension of the ethical in such a way that our understanding of both is transformed. Only after this ‘empiricist conversion’ can we truly think of a Deleuzian politics that does justice to a plane of immanence ‘immanent only to itself’. (shrink)