In his memorial for Gilles Deleuze, Derrida remarks that he has always felt an affinity with the work of Deleuze and, indeed, considered him the thinker of their generation with whom he was the closest.1 Derrida, however, also notes that there are two points that he wished he could have discussed further with Deleuze: Deleuze's insistence on the term and his definition of philosophy as the creation of concepts. Thus while their thought-and their thinking of thought-resonates on many levels, it is also with respect to their understandings of philosophy and thought in general that the Derridean and Deleuzian projects can be seen to diverge. This essay begins to investigate the affinity between Deleuze and Derrida by considering theme central to both: a conception of thought that puts it into fundamental relationship to movement, and views this movement of thought as that is roused by internal difference. While a point of comparison, this consideration of the movement of thought-the movement that is thought-also leads to the specification of certain differences. First, the movement of thought for Deleuze is precisely a movement that traverses (it is the line of the transversal), while for Derrida it is the movement that occurs when cannot traverse, when limits and borders are impassable-the movement within aporia. second, Deleuze and Derrida differ, albeit subtly, with respect to the temporal aspect of thought. This difference can also be understood as the difference between transcendence and immanence or between mediation and immediacy, although here it will be articulated as the difference between the yet to come and becoming.2 These differences, though, lead to a further point of convergence: the movement of thought is implicated in a structure of possibility and impossibility that indicates what must be thought. In Derrida, this structure takes the form of undecidability and contamination. Derridean undecidability finds its Deleuzian counterpart in the zones of indiscernibility that, according to Deleuze, characterize the becoming of philosophical concepts. Thus, it is in returning to the Deleuzian theme that caused Derrida to grumble a bit that we can see the completion of their affinity.3 The bad conscience experienced in undergoing aporia, in accordance with which we must always think, is indeed a concept in Deleuze's sense: it attests to our present problems.4 Consequently, the differences between the Deleuzian and the Derridean understandings of thought's movement should be viewed as arising from the divergent paths they take with respect to the consequences of the internal alterity that gives cause to think. Derrida advances bad conscience and responsibility while Deleuze advances experimentation and creation. Their respective accounts of the nature of the movement of thought underscore this difference. By articulating these particular variations, we will develop a better understanding of the more general and obvious ones such as the difference in style and ethos, and gain a sense of the compatibility or incompatibility of their projects. Hence, we will discover that there is something in Deleuze that requires that we attest to otherness and something in Derrida that requires that we engage in inventive creation. Thought's Movement: From Infinite Speed to Moving within the Space of Aporia Derrida and Deleuze share the idea that thought is movement and that this is a movement of becoming-other that is provoked by internal difference. One differs from oneself, and it is these gaps and divergences within the self that cause thought. Not only is this internal alterity-otherness within the self-that which gives rise to thought, it also characterizes the nature of thought itself. Thus, Deleuze avers that one does not think without becoming something else, something that does not think-an animal, a plant, a molecule, a particle-and that comes back to thought and revives it. …