Deleuze begins his next paragraph by admitting that there is not "any resemblance between Nietzsche's Dionysus [or Zarathustra, perhaps?] and Kierkegaard's God"; indeed, "the[ir] difference is insurmountable" (DR 8). Far from undercutting his abrupt comparison of these two (anti-)philosophers, however, Deleuze notes that this difference makes "their coincidence concerning" repetition all the more remarkable (Ibid.).
As I mentioned at the beginning of SR 1.8, Kierkegaard and Nietzsche, at the very least, share a rather quirky expressivist writing style that rejects the systematic, logical, and propositional methods of their titanic forebears. So what's the purpose of their quirky methods and styles? In a phrase: the production and introduction of "movement" into the very work of philosophy (Ibid). That is, not merely the conceptualization, description, or Hegelian mediation of movement or change. Rather, "[t]hey want to put metaphysics [itself] in motion" (Ibid). Nietzsche and Kierkegaard do not want to prove anything; they do not want to walk their readers through an epistemological, moral, or historical system or theory. In short, they are not metaphysical architects. Rather, they invent something else — conceptual "vibrations, rotations, whirlings, gravitations, dances [and] leaps which directly touch the mind" of readers (to come) (Ibid). Riffing off of Deleuze's analysis here, one might call these enigmatic philosophical inventions the introduction of stage directions into philosophy: "an incredible equivalent of theatre within philosophy" (Ibid).
But what does any of this mean? Isn't it, as a good and very incisive friend once asked, a bit silly? Is this really "a new philosophy," or is it merely a suspicious aestheticization of philosophy? ("Suspicious" in a sense similar to the tone of Walter Benjamin's alignment of fascism with an aestheticization of politics [Illuminations 242].) My friend, in short, questions the a priori goodness or worthwhileness or usefulness of aestheticization or theatricalization.
Though I am not equipped to answer his question just yet (in fact, I'm inclined to agree with him in principle: aestheticization, of course, is not an a priori good), perhaps a useful passage from James Williams' guidebook to Difference and Repetition might offer a good place to begin:
The Deleuzian concept of theatre responds to the problem of how to create without representing. Initially, he speaks of the movement of Kierkegaard's and Nietzsche's works, contrasting it with Hegel's logical movement, as a way of explaining their violent reaction to his philosophy [. . .] Hegel's logic moves from a representation to another that negates it (This is not that.) and on to a synthesis (This as both that and that.). Whereas Kierkegaard's and Nietzsche's theatre do not allow for a representation to emerge. Instead, the movement is not from one thing to another but in one changing individual. (GDDR 44)
Aside from Williams' rather crude summation of Hegel (a typical misprision used by those seeking to score a point against this philosophical titan), he nevertheless draws out an important point: that a work like Phenomenology of Spirit differs from a work like Repetition or Thus Spoke Zarathustra insofar as the first aims to work with its readers through the movements of various concepts, situations, and actors from a methodological distance ("lord and bondsman" constitute, perhaps, the most famous instance) while the latter texts aim to do something to the reader. They strives to achieve proximity with the reader, to disturb their present, and to occasion a change (to come) that they cannot necessarily predict. In Hegel, then, one observes the representation of movement and an argument that certainly may lead to a shift in his reader's attitude or position. In Kierkegaard and Nietzsche, however, one enters immediately into an unfamiliar setting that does not lead but, rather, that opens and exposes readers to something unseen and unrepresented up ahead or around the corner (hence Deleuze's formulation, "theatre of the future" [8, emphasis added]).
When a reader enters into Repetition, for instance, one does not encounter the writing of Kierkegaard qua Kierkegaard. Rather, they encounter a mask and a voice attributed to a pseudonym, "Constantin Constantius." (In Fear and Trembling the "author" is Johannes del Silentio.) Deleuze argues,
We find here a thinker who lives the problem of masks, who experiences the inner emptiness of masks and seeks to fill it, to complete it, albeit with the 'absolutely different' — that is, by putting into it all the difference between the finite and infinite, thereby creating the idea of a theatre of humour and of faith. When Kierkegaard explains that the knight of faith so resembles a bourgeois in his Sunday best as to be capable of being mistaken for one, this philosophical instruction must be taken as the remark of a director showing how the knight of faith should be played. And when he comments on Job or Abraham, when he imagines the variations of Agnes and the Triton, he writes the tale in a manner which is clearly that of a scenario. [. . .] 'I look only at movements' is the language of a director who poses the highest theatrical problem, the problem of a movement which would directly touch the soul, which would be that of the soul. (DR 8-9)
Before attempting to unpack this, it might be worth quoting one of the Kierkegaard passages to which he's referring here:
For my part, I presumably can describe the movements of faith, but I cannot make them. In learning to go through the motions of swimming, one can be suspended from the ceiling in a harness and then presumably describe the movements, but one is not swimming. In the same way I can describe the movements of faith. If I am thrown out into the water, I presumably do swim (for I do not belong to the waders), but I make different movements, the movements of infinity, whereas faith makes the opposite movements: after having made the movements of infinity, it makes the movements of finitude. Fortunate is the person who can make these movements! He does the marvelous, and I shall never weary of admiring him; it makes no difference to me whether it is Abraham or a slave in Abraham's house, whether it is a professor of philosophy or a poor servant girl — I pay attention only to the movements. But I do pay attention to them, and I do not let myself be fooled, either by myself or by anyone else. The knights of the infinite resignation are easily recognizable — their walk is light and bold. But they who carry the treasure of faith are likely to disappoint, for externally they have a striking resemblance to bourgeois philistinism, which infinite resignation, like faith, deeply disdains. (FT 38-39, emphasis added)
How do we read this passage with Deleuze? As I read and reread it, I find that I oscillate between feeling certain of what to say in response — that I am plugged into how Deleuze is reading Kierkegaard — and feeling completely, utterly befuddled. What, after all, am I to make of the difference between the finite and the infinite (Deleuze's, regarding the masks; Kierkegaard's, regarding the swimmer and knight of faith)? And what does this have to do with the theatre? With humour and faith? With repetition? For Kierkegaard, perhaps one might say that the finite and infinite correspond to the measurable and measureless, the extensive and intensive, the mediate and immediate. In the case of Abraham, his decision to obey God and go through with sacrificing Isaac constitutes an "infinite" movement of faith, for he does not reason with or against it. He immediately and intensively (which is to say, reflexively) obeys with "passion" (FT 42). Afterwards, once the Angel of the Lord stays his hand, he must return to his everyday life, living with the son he had almost slain, re-incorporating himself into the finitude of the mundane and habitual. And yet, despite continuing to enjoy or be pained by the finitude of his everyday life, Abraham still experiences the immanent "blessedness of infinity" (FT 40). Indeed, the ideal knight of faith manages to "change the leap [of faith] into life into walking, absolutely to express the sublime in the pedestrian—only that knight can do it, and this is the one and only marvel" (FT 41). A swimmer, on the other hand, learning a mere physical skill, will eventually move from the measured, extensive movements of practice to the immediate (and thus infinite) reflexes of a seasoned swimmer (who no longer needs to mediate his interaction with the water with lessons or practice). Does this make sense?
While this helps a bit with the Kierkegaard passage itself and the difficulty of learning how to become a knight of faith, perhaps I need another tactic in order to understand Deleuze's reading. What issues does he raise concerning Kierkegaard's style (and this passage in particular)?  The issue of Kierkegaard's masks and the difference of the finite and infinite.  Kierkegaard's comparison of the knight of faith and the bourgeois philistine as a matter of stage direction.  The problem of movement as the problem of the soul, of touching the soul immediately. So . . . now what?
Deleuze argues, I think, that the emptiness of Kierkegaard's masks (Constantin Constantius is not a "real person," after all) creates the conditions under which he can actually perform the absurdity he works to conceptualize again and again throughout his life. According to the Stanford Encyclopedia of Philosophy,
Christian dogma, according to Kierkegaard, embodies paradoxes which are offensive to reason. The central paradox is the assertion that the eternal, infinite, transcendent God simultaneously became incarnated as a temporal, finite, human being (Jesus). [. . .] If we choose [to accept this paradox on] faith we must suspend our reason in order to believe in something higher than reason. In fact we must believe by virtue of the absurd.
Much of Kierkegaard's authorship explores the notion of the absurd: Job gets everything back again by virtue of the absurd (Repetition); Abraham gets a reprieve from having to sacrifice Isaac, by virtue of the absurd (Fear and Trembling); Kierkegaard hoped to get Regine back again after breaking off their engagement, by virtue of the absurd (Journals); Climacus hopes to deceive readers into the truth of Christianity by virtue of an absurd representation of Christianity's ineffability [Concluding Unscientific Postscript?]; the Christian God is represented as absolutely transcendent of human categories yet is absurdly presented as a personal God with the human capacities to love, judge, forgive, teach, etc. ("Kierkegaard's Religion," original emphasis)
This absurdity, Deleuze seems to be arguing, is not just a conceptual or propositional element of Kierkegaard's oeuvre. Moreover, it is a stylistic feature. There is something absurd, after all, in a Christian philosopher who can only philosophize through the differentiation of a mask, through the leap from his own signature to that of a character, from the method of systematic metaphysics to the literary invention and lengthy, detailed setting-up of heuristic scenarios. The (often painful) precision of Kierkegaard's re-tellings (of Abraham, of Job) play out gesture-by-gesture the absurdity of faith, and this faithful precision (the hallmark of "humor," according to Henri Bergson) is made possible and given form through the donning of masks and the fictional creation of situations in which questions like, "Is repetition possible?" become urgent. Deleuze is not equating Abraham's or Job's respective leaps of faith, of course, with the often mad absurdity of Kierkegaard's style, but he is insisting that this theatricality is the essential (not accidental) condition of Kierkegaard's (moving) conceptual power. The immanent problem of Kierkegaard's oeuvre, as Deleuze sees it, is an expressive style that calls upon readers to play through the scenarios, to attend to, think through, and even become the occasion of a faithful reflection. (But what does this have to do with repetition? I hope my own readers can already see the glimmer of an answer to this question, but I'll come back to it more directly in a moment.)
What of Nietzsche? Using The Birth of Tragedy (1872) as an example, Deleuze argues that Nietzsche's provocative analysis of "ancient theatre" is itself a mask for "the practical foundation of a theatre of the future, the opening up of a path along which [he] still thinks it is possible to push Wagner" (DR 9). In other words, Nietzsche sets up a heuristic condition — an experimental test — which does not study an outcome or result but proffers an opportunity, a philosophical situation or instrument, in which the reader (to come) can play through its proposed steps: "the respective roles of text, history, noise, music, light, song, dance and décor in this theatre of which Nietzsche dreams" (Ibid.). Nietzsche's later critiques of Wagner in Human, All-Too-Human (1878) and Nietzsche Contra Wagner (1888), according to Deleuze, is not about whether or not Wagner evoked movement but that his evocations never moved beyond (and, in fact, located movement in) "a nautical theatre in which [listeners] must paddle and swim rather than [. . .] walk and dance" (Ibid.). As someone who has very little experience listening to Wagner (let alone attempting to learn how to inhabit Nietzsche's initial enthusiasm and later disillusionment with his work), I'm struggling to give Deleuze's claims here a bit more substance, but it is clear nevertheless that he reads Thus Spoke Zarathustra as Nietzsche's ultimate attempt to counteract Wagner's operatic posturings and gesturings with a "score" of his own (Ibid.).
Every attempt to read the text, Deleuze argues, leads to a whole series of directorial concerns:
How can [TSZ] be read without searching for the exact sound of the cries of the higher man, how can the prologue be read without staging the episode of the tightrope walker which opens the whole story? At certain moments, it is a comic opera about terrible things; and it is not by chance that Nietzsche speaks of the comic character of the Overman. Remember the song of Ariadne from the mouth of the old Sorcerer: here, two masks are superimposed — that of a young woman, almost of a Korē, which has just been laid over the mask of a repugnant old man. The actor must play the role of an old man playing the role of the Korē. Here too, for Nietzsche, it is a matter of filling the inner emptiness of the mask within a theatrical space: by multiplying the superimposed masks and inscribing the omniprescence of Dionysus in the superimposition, by inserting both the infinity [or, we might say, intensiveness] of real movement and the form of the absolute difference given in the repetition of eternal return. When Nietzsche says that the Overman resembles Borgia rather than Parsifal, or when he suggests that the Overman belongs at once to both the Jesuit Order and the Prussian officer corps, we can understand these texts only by taking them for what they are: the remarks of a director indicating how the Overman should be 'played'. (DR 9-10)
In Nietzsche Contra Wagner, Nietzsche argues that Wagner "had the commanding instinct of a great actor in absolutely everything" (The Anti-Christ, Ecce Homo, Twilight of Idols, and Other Writings 267). In Deleuze's formulation above, Nietzsche's TSZ aims to move beyond the concerns of an actor (i.e., how do I play this particular role?) to that of a director or composer arranging a whole stage of movements (i.e., how do you play this role in conjunction with this one, how do you move between them?). Come reader, Deleuze's Kierkegaard and Nietzsche plead, try your hand at these movements. Read the text aloud and attempt to inhabit and fill these empty masks. What happens? What paths open ahead of you? What sort of leap do you discover? What new dance or walk do you learn? How has your desire shifted? Can you dance through your everyday? Can you become a mirror that repeats the singularity of Abraham? of Zarathustra? of Dionysus? And what "absolute difference" does this repetition occasion in your everyday? Nietzsche and Kierkegaard: Shakespearian philosophers.
One might ask, Is this still philosophy, then? If Kierkegaard and Nietzsche want to do theater, why not become actual composers and/or directors? Answer: why should they? Does one ever take seriously the questions, Why is this work of literature so philosophical? Why didn't the novelist or dramatist just go ahead and write philosophy? Why didn't Woolf, for instance, just study and create a philosophy of time rather than compose works of art which express and immanently theorize time? Better answer: Because they had a taste for philosophy. Because they did not desire to write a novel or a play more than a work of (speculative) philosophy. Because prescribing someone a mode or genre presumes a limited set of purposes and tools. Because what they produced in philosophy is, perhaps, far more interesting and noteworthy than anything they would have produced as novelists or playwrights. Shorter answer: Because they simply didn't. When my friend once heard me defend Deleuze's style (which is, after all, so different from Kierkegaard and Nietzsche) and its affinities with a few literary modernists, he smiled and approved. "I'm in full agreement," he said, "and I welcome the idea of releasing Deleuze of the requirements of philosophy."
"Not so fast," I responded . . .
Next up: Deleuze positions Kierkegaard and Nietzsche against Hegel. Also, we'll get a bit clearer on the important association of theater, movement, and repetition (vs. mediation and representation).