Our only teachers are those who tell us “do with me,” and are able to emit signs to be develop in heterogeneity rather than propose gestures for us to reproduce. (Deleuze, Difference and Repetition (hereafter DR), 26).Difference and Repitition, 26DR 26)
Duns Scotus, Spinoza, and Nietzsche are three moments in the “history of the philosophical elaboration of the univocity of being.” (DR 48) This history is progressive: Spinoza “marks a considerable progress.” And Nietzsche becomes world-historical (he offers “a Copernican revolution” (DR 50)) by opening the “possibility of difference having its own concept,” that is “eternal return” not of the “Identical,” but rather “returning constitutes the only Same of that which becomes,” (DR 50; it matters to Deleuze that what returns are the ‘extreme’ or ‘excessive’ forms). The history of progressive conceptual development is not just a “theoretical” exercise, but delivers a “practical” criterion in Nietzsche.
As the epigraph to the post suggests, for Deleuze the history of philosophy is an occasion to encounter exemplary thinkers that both invite their readers to think with their thoughts as well as demand from their very best readers a development that does not mindlessly repeat the original, but in the development introduce variance. This creative act of the historian of philosophy, this repetition and difference, which Deleuze calls the method of dramatization is, thus, a way to conceptualize the doing of the history of philosophy as a means toward progress in philosophy. Deleuze attributes the origin of the method to “Kierkegaard and Nietzsche,” who “invent an incredible theatre within philosophy, thereby founding simultaneously this theatre of the future and a new philosophy.” (DR 9) So, Nietzsche plays a double role of the founder of a method and a contributor to a key development in which it is deployed. (That double role is -- witness Kierkegaard -- apparently not necessary.)