Although it is not clear that Deleuze and Guattari were simply and unambiguously Jungians, they extensively engaged with Jung’s work in both affirmative and critical ways. For instance, in Difference and Repetition, Deleuze writes: “Was not one of the most important points of Jung’s theory already to be found here: the force of ‘questioning’ in the unconscious, the conception of the unconscious as an unconscious of ‘problems’ and ‘tasks’? Drawing out the consequences of this led Jung to the discovery of a process of differenciation more profound than the resulting oppositions.” The concern with “problems” and “differenciation” is central to Deleuze’s project in what many consider his magnum opus, and it is striking that Deleuze articulates such a strong resonance between his work and that of Jung, as Jung’s influence on Deleuze has not tended to be emphasized by scholars. Similarly, there are several passages in which Deleuze takes Jung’s side against Freud, who nominated Jung his “successor and crown prince” in 1910, and then excommunicated him around 1913 for his purported psychoanalytic heresies. One of the most revealing of these passages by Deleuze is in L’Abécédaire, recorded as a long television interview that would only air after his death, in which he discusses “a text that I adore by Jung” about Jung’s dream of descent through successive subterranean strata, at the deepest layer of which Jung finds a multiplicity of bones that Freud insists on reducing to the unity of a death-wish. Deleuze presents this encounter as a primary example of his central concepts of multiplicity and assemblage, which he portrays Jung as understanding, contrary to Freud’s egregious misunderstanding of these concepts, an instance that also finds brief mention in A Thousand Plateaus, where Deleuze and Guattari write that “Jung is in any event profounder than Freud.” Deleuze also makes positive references to Jung in Nietzsche and Philosophy, with Claire Parnet in Dialogues II, and with Guattari in Anti-Oedipus, and it even seems possible that Deleuze and Guattari’s concept of the rhizome from A Thousand Plateaus is at least partially derived from Jung’s discussion of this concept in 1961’s Memories, Dreams, Reflections.
In 1969’s The Logic of Sense, Deleuze explicitly employs the term “synchronicity,” and significant portions of that book seem to be explorations of something very much like Jungian archetypes and the subtle kind of formal causation characteristic of the late Jungian conception of synchronicity in other terms. Deleuze indirectly defines synchronicity as a form of resonant correspondence that is not merely a linear logical series operating in terms of the causes and effects of efficient causation, while Jung, in the subtitle of the book Synchronicity, defines it as “an acausal connecting principle,” both of which definitions Deleuze implicitly takes up later in the same book, in relation to the Stoics and Leibniz, in his discussion of “alogical incompatibilities and noncausal correspondences,” of which he writes that “astrology was perhaps the first important attempt to establish a theory,” as this ancient mode of thought posits a persistent formal, as opposed to efficient, causal (or perhaps quasi-causal, or even acausal) correspondence between the movements of the heavens and events in the human domain.
A decade-or-so later, in A Thousand Plateaus, the figure of Professor Challenger—who is apparently an embodiment of the assemblage of Deleuze and Guattari based on a character by Arthur Conan Doyle—is giving an obscure and difficult lecture which seems partially designed to prune back the audience (and perhaps those reading about this oddly hallucinatory presentation) to the few steadfast diehards willing to expend the extraordinary effort required to comprehend these esoteric domains, so that “the only ones left were the mathematicians, accustomed to other follies, along with a few astrologers, archaeologists, and scattered individuals.” In the same book, Deleuze and Guattari describe Jung’s approach as “integrating” any given animal image found in dream or myth “into its archetypal series,” though they express dissatisfaction with this construction, seeking further to deterritorialize Jung’s theory, which they clearly find great value in along with the Jungian approach of Gaston Bachelard in Lautréamont (about which James Hillman also wrote), to suggest that “we sorcerers” can discern that “there is still room for something else, something more secret, more subterranean” constituted in a becoming beyond the “progress or regress along a series,” which they associate with “the whole structuralist critique of the series,” a critique which “seems irrefutable.” However, later in the same text, they affirmatively quote H.P. Lovecraft’s evocation of an ascendance through n-dimensions “up to the dizzy and reachless heights of archetypal infinity” in their description of the “plane of consistency” (as opposed to the “plane of development”) which is the locus of becomings “written like sorcerers’ drawings” on that immanent plane, “the ultimate Door providing a way out” or, alternately, “the gates of the Cosmos.”
Deleuze and Guattari’s critique of the archetypes as “intrinsic qualities” rather than the conception that they advocate, in which “cosmic forces” or “expressive qualities” (which are “fictional” like the infinitesimal form of the calculus created by Leibniz) are real but nonactual formal causes characterized by their function in specific assemblages of becoming—nomadic paths enacting a vital autonomy for which particular effectuations are derivative points, so that the integral trajectory is primary and the series derived from it secondary—is already prefigured in Jung, who remained ambivalent about the archetypes’ ontological status. Thus, rather than rejecting altogether Jung’s archetypal theory, Deleuze and Guattari, like many Jungians, have refined that theory, rendering it more subtle and general by suggesting that the locus of becoming is not found primarily in the linear, sedentary series of chronological development, but in temporally nonlinear “transformational series” across scale ascending, as in Jean Gebser’s concretion of time, through increasing degrees of freedom. They seem to suggest that the integration of n-dimensional archetypal series is precisely the conceptual construction characteristic of the Leibnizian, infinitesimal version of the integral calculus, and thus that the metaphysical integration explicitly correlated with the integral calculus specifically integrates these nonlinear and nonlocal archetypal series of diachronic and synchronic resonances, which is precisely the mode of relation characteristic of Jung’s late expression of synchronicity, syncategorematically approaching the transcendental archetypal potentialities in their multiplicitous singularity.
While these discussions of Jung’s work are profound, they require a Sherlock Holmesian reading of subtle clues to decipher, a recognition that Deleuze implicitly affirms in Difference and Repetition, writing that “a book of philosophy should be in part a very particular species of detective novel,” with hints leading the reader to revelations of ultimately complex networks of intertwined relations that were formerly occluded. Deleuze, with and without Guattari, often only evokes these realms of thought, teasing the reader with references to Jung and his work in ways that cannot easily be pinned down, that remain elusive. One suspects the reason for this coyness is that, although Deleuze clearly found great value in Jung’s work, he also understood that Jungian thought has enjoyed an uneasy relationship with the main streams of academia, as Jung brilliantly and profoundly explored conceptual domains that were often beyond the pale for the dominant spheres of the twentieth century academy. However, this situation currently bears signs of a rapid shift, and the increased recognition of Deleuze and Guattari’s extended, though complex, engagement with Jung might help to carry the Swiss psychologist from the marginal frontiers of thought, where he remains the undisputed king, into the central nodes of academic discourse where Freud has long presided, at least in the humanities. In fact, Deleuze and Guattari explore most of the same uncharted domains as Jung, though their writing is so difficult and complex that only those who are paying very close attention, and in many cases who are already familiar with Jungian thought, will discern the deep resonances between these thinkers. One suspects that this was a subtle and purposive strategy by Deleuze and Guattari, which has been extraordinarily efficacious in allowing their work to occupy a central place in continental thought, while also allowing them to engage with relatively marginal Jungian concepts, winking at the Jungian cognoscenti while generally escaping the notice of those within academia who unquestioningly accept the overly hasty dismissal of Jung’s work largely instigated by Freud. Ultimately, Deleuze and Guattari implicitly seem to have understood Hillman’s admonition that “Freud and Jung are psychological masters, not that we may follow them in becoming Freudian and Jungian, but that we may follow them in becoming psychological,” though of course the same can also be said about following Deleuze and Guattari as philosophical and psychological masters.
 Gilles Deleuze, Difference and Repetition (New York: Columbia University Press, 1995) 317n17.
 A notable exception is Christian Kerslake’s excellent Deleuze and the Unconscious.
 Sigmund Freud and C.G. Jung, The Freud-Jung Letters (Princeton, NJ: Princeton University Press, 1994) 104.
 C.G. Jung, Man and His Symbols (New York: Anchor Press, 1964) 56-58.
 L’Abécédaire de Gilles Deleuze 1996. Gilles Deleuze and Felix Guattari, A Thousand Plateaus (Minneapolis, MN: University of Minnesota Press, 1987) 241.
 Gilles Deleuze, Nietzsche and Philosophy (New York: Columbia University Press, 2006) 212n8.
 Gilles Deleuze and Claire Parnet, Dialogues II (New York: Columbia University Press, 1987) 80.
 Gilles Deleuze, Anti-Oedipus (New York: Penguin Classics, 2009) 46, 162, 278.
 C.G. Jung, Memories, Dreams, Reflections (New York: Vintage Books, 1989) 4.
 Gilles Deleuze, The Logic of Sense (New York: Columbia University Press, 1990) 120, 170-71.
 A Thousand Plateaus 43, 57, 235, 237, 250-51, 333.
 A Thousand Plateaus 306, 322-23, 380, 398, 420, 507.
 Difference and Repetition xx.
 James Hillman, Re-Visioning Psychology (New York: HarperCollins Publishers, 1992) xii.