After thinking about it for a few days, I find I can't leave the subject of the religious aspect of ER without thinking some more about the parallels between it and Buddhism.
Ultimately, I think ER functions for Deleuze as a kinda of mystical limit of philosophical thought. Consider the way it unifies all opposites. Repetition for-itself converts into Difference in-itself. This precise moment is the unique and final end of time only if we realize that it is just a moment like any other. The qualitative difference of actual and possible get joined into a single image that synthesize all of time. The pure and empty (ie. formless) form of time that fractures its line into before and after once and for all, simultaneously describes how time continuously repeats this phase change, producing a never-ending novelty of new forms. The formless form of time creates the form of formlessness.
Or some shit like that. The point of all these different formulations is just to push our thinking to the point of breakdown, really to induce the paradoxical thought of Eternal Return directly, so that we reach "the magic formula we all seek: PLURALISM = MONISM". The practice of this kinda of thinking is the climax Deleuze's philosophy builds towards again and again -- one formulation, by definition, can never be enough. You have to go over 'the same' pattern endlessly, each time creating 'it' anew. Which is why it's appropriate here to quote what I wrote in the margin at the end of chapter 1:
The system is a (non)-system. But this has nothing to do with the "harmony and balance of opposites". Yin and Yang are not an equilibrium, even a dynamic one. They are the symbol of productive difference, internal to everything, always producing more difference. They just shouldn't be drawn symmetrically.
So I think you can see Deleuze as a sort of mystic. After all, isn't his hero Spinoza, captain of rational mysticism, the famous atheist who believed that God is Nature? Perhaps at one point I would have fought tooth and nail against this interpretation of his philosophy. In retrospect I think that was mostly because I had an inadequate understanding of what mysticism could be. I thought of mysticism as entirely devoted to the idea of the essential unity of all things. Maybe this was a little better than imagining all things as created according to some heavenly bearded dude's inscrutable plan, but it still seemed to involve a transcendence that leveled all distinctions as illusory. Of course, mysticism could be, and often is, exactly that. But I've come to appreciate that it has another potential, so long as you come to see it as a practice, rather than a doctrine.
While this reevaluation of mysticism has probably been brewing ever since I read Spinoza (I called myself an anarcho-theist for a while), it's really been consistently practicing meditation that has brought me back to it. The reason is very simple. I experience a significantly altered version of reality on a daily basis. While I can't say that I experience mystic oneness with the cosmos every morning, I certainly experience a dissolution of my physical boundaries and a direct transformation of my self-understanding. If you practice this consistently enough you simply become unable to dismiss these experiences mere "hallucinations" in the way we (obviously also incorrectly) dismiss people's drug trips. The conclusion is not so much that these experiences are necessarily somehow deeper or realer than everyday experience, but simply that they too are real; our customary everyday boundaries are only one possible way of dividing up the world.
The key here is the practice, the training of the mind/body, the experimentation. Ultimately, this is way more important than exactly what the practice leads you to conclude is the underlying reality. In fact, we should look at all religious beliefs in this same manner -- how does believing X (or not) affect the way you live? As Deleuze puts it, "Eternal return is not a faith, but the truth of faith", or in another context, "Pascal wagers on the transcendent existence of God, but the stake, that on which one bets, is the immanent existence of the one who believes that God exists". Pascal wagers that God exists not as a cynical way to cover his ass in the event of a posthumous pearly gates interview, but because he wants to live like someone who is willing to take that risk, to make the bet of belief. Similarly, to believe in mysticism is to bet that investigating the altered states and redrawn boundaries can help us live better. I'm willing to wager that these experiences are as real as any others, because if I make this wager I can live like someone who experiences new stuff all the time, stuff hidden in plain sight.
Basically I'm arguing that there is a version of mysticism, rooted in the practice of concentration, that fits well with Deleuze's philosophy -- it takes the mystical unity of experience not as a limit to what's out there, but as a principle to motivate the investigation and production of more experience. Repetition for-itself is difference in-itself.
A lot of this reinterpretation of mysticism is just now crystalizing for me as I read Shinzen Young's The Science of Enlightenment. If he's "taking the mist out of mysticism" I guess Deleuze must be putting it back in. I won't go deeply into the book at the moment since my colleagues over at The Capitalist Axiomatic are hard at work on the forthcoming full review. The important bits in this context are his review of the overlap between very the different mystical traditions of the world in Chapter 3 and the way his explanations of the paradoxes of Buddhist doctrines so often remind one of Deleuze in Chapters 5-10.
After seeing Young's less denominational version of mysticism I'm tempted to reinterpret everything I've read about Buddhism in its light. For example, I've been noodling around with a different understanding of the The Three Characteristics. Usually these are stated as impermanence, suffering, and no-self. What the Buddha Taught already suggested that a couple of these were almost mis-translations, or at least easily subject to misinterpretation. Impermanence is still just what it sounds like -- nothing is permanent, the world is Heraclitean flux. "Suffering", though, should apparently be more like "unsatisfactoriness", which already eases some of my problems with the term -- no thing is an island, sufficient unto itself or "self-satisfying". And "no-self" should apparently be construed less in the sense of self-abnegation or annihilation than as a statement of the fact that you are not a substantial thing with certain essential properties, but a process that comes together (or doesn't) to produce you.
If you massage these concepts around a little, you might see them as descriptions of a single experience from three different angles. Impermanence describes experience from the outside, as if you were watching bubbles float by on the river. They come into view and pass out of it. Unsatisfactoriness describes experience from the inside. No experience is completely unlinked from the totality of experience, none is a final stopping or stable resting point since one always leads to the next and the next. It's easy to see how this unsatisfactoriness becomes suffering if you've identified your self with this inside experience; the experience isn't stable or peaceful but always splitting into others, connected to other experiences which lead outside it. Finally, if you put these two points of view next to one another, you become unsure where "you" fit. Your experience constantly alternates between these two. Are you watcher or watched? And neither point of view is stable enough to provide for anything like a substantive on-going I/eye. Should we say that you are "fractured" between these two views of yourself? That "you" only emerge from some process by which they are placed into relationship? And isn't the process we're talking about here basically Time?
I won't belabor this by trying to make it match Deleuze's description of Eternal Return point for point. I do think you can see how all the same elements are present, the analogies are suggestive, and the underlying spirit is very similar. If PLURALISM = MONISM, then does ETERNAL RETURN = ENLIGHTENMENT?