The Thinkable and the Unthinkable II: How Arkady Plotnitsky’s Complementarity Intersects with Deconstruction—and Where Does SFI Stand?

In recent years, the Santa Fe Institute (SFI) has become a major interdisciplinary hub for studying complex systems, artificial intelligence, and the nature of cognition. With roots in American psychology (particularly cognitive science and behaviorism) and analytic philosophy of science, many SFI research programs implicitly assume that human intelligence is fundamentally “rational-calculable” and, therefore, amenable to complete formalization or computational modeling. As a result, SFI’s approach can appear to be a “hybrid” theory that incorporates insights from various scientific and philosophical traditions—yet it arguably remains monolithic in its rationalist and epistemological commitments.

Arkady Plotnitsky, a Distinguished Professor of Philosophy and Literature at Purdue University, offers a crucial counterpoint to the reductionist frameworks commonly found at SFI. His grounding in Continental Philosophy frequently clashes with the Analytic Philosophy tradition, which tends to dominate the institutional discourse of contemporary universities. Drawing on Jacques Lacan’s critique of the "discourse of the university," we might situate Analytic Philosophy alongside academic psychology, both of which Lacan argued deny the truth of the unconscious and overlook the transformative impact of psychoanalysis on the humanities and social sciences.

Moreover, while the "science-centered" researchers at SFI claim a rigorous scientific perspective, they paradoxically adopt a narrower view of both philosophy and science by disregarding the epistemological and ontological challenges posed by quantum mechanics. One might expect Plotnitsky—a humanities scholar—to approach cognition, mind, and meaning primarily through a philosophical lens. Ironically, his engagement with science is more expansive than that of many "science-centered" researchers, resisting exclusionary reductionism by fully integrating the disruptive implications of quantum mechanics. His approach not only engages with the paradoxes of quantum theory but also grapples with deconstruction’s critique of Rationalist epistemologies and their often-unexamined metaphysical assumptions.

By working at the intersection of quantum theory, philosophy, deconstruction, and psychoanalysis, Plotnitsky illuminates dimensions of reality and knowledge that resist classical, deterministic, and Rationalist epistemologies—where the capital "R" marks the presence of unconscious metaphysical commitments masquerading as pure logic. In doing so, he challenges not only the philosophical underpinnings of mainstream cognitive science but also the institutional structures that continue to suppress alternative epistemologies in favor of computational and mechanistic models of intelligence.

Ironically, this humanities scholar offers a more comprehensive scientific perspective than those who claim to be “science-grounded” yet remain tethered to a strictly deterministic, rationalist view of cognition, mind, and meaning. Unlike many at SFI, Plotnitsky aligns himself with less metaphysically laden discourses—psychoanalysis, deconstruction, and physics—each of which actively interrogates the epistemological limits and conceptual instabilities that Rationalist frameworks seek to suppress.

By examining the irreducible “unthinkable” dimension that appears in modern physics and psychoanalysis alike, Plotnitsky shows why attempts to reduce human intelligence to a rationalizable model of mind can face structural limits—limits that typical American psychology and mainstream AI research often ignore. The questions we might pose to the Santa Fe Institute, then, are: Does it truly engage with quantum mechanics as a field that challenges classical conceptions of knowledge? Or does it sideline the more unsettling implications of known physics, quantum theory, effectively “denying” a major part of modern physics because it does not fit an already assumed epistemological framework?

Plotnitsky’s paper, “The Thinkable and the Unthinkable in Psychoanalysis and Philosophy, From Sophocles to Freud to Derrida”, was published alongside my inaugural essay, "Let Us Not Forget the Clinic" (both titles alluding to Derrida titles) in The Undecidable Unconscious: A Journal of Deconstruction and Psychoanalysis, the journal I founded and co-edited. Both papers appeared in Volume 1, Issue 1 (2014), marking a critical engagement with the intersections of deconstruction, psychoanalysis, and non-classical (non-deterministic) epistemologies.

(My inaugural essay aimed to steer the deconstruction-heavy academics working on the journal toward practical application, but in retrospect, Plotnitsky’s paper might have been a more fitting—and likely more welcome—choice for an inaugural paper. His essay not only engaged more with the journal’s core intellectual concerns but also provided a compelling explanation for why we named the journal The Undecidable Unconscious.)

Plotnitsky’s work plays a crucial role in the broader discourse on deconstruction, psychoanalysis, and complexity theory, offering key insights into their shared critique of deterministic epistemologies. These themes are also central to my ongoing work in The Undecidable Unconscious, my blog that shares its name with my journal. Two particularly relevant posts, “Incompleteness, the Unconscious, and the Supplement: Toward an Ethics of Cyborgian Care” and “When Philosophy and Psychology Seek a Rational-Calculable Mind—and Why Deconstruction and Psychoanalysis Resist,” further explore epistemological limits, complexity, and the unthinkable, positioning psychoanalysis and deconstruction as essential correctives to deterministic models of cognition and reality.

All of these texts, in different ways, warn us that if we fail to reckon with a non-classical dimension of mind—whether it be called the “unthinkable,” the quantum, or the unconscious—we risk flattening intelligence into a computational schematic that excludes complexity, ambiguity, and the irreducible dimension psychoanalysis and deconstruction reveal.

In what follows, I will maintain the full content of my earlier discussion of Plotnitsky’s complementarity, but embed it in a broader critique of reductionist-exclusionist tendencies at places like SFI. I will also weave in some additional reflections on quantum mechanics, psychoanalysis, Jacques Lacan’s four discourses (the master, the university, the analyst, and the hysteric), and how these shed light on the way “unthinkable” ideas often get dismissed within institutional contexts.

Each of these texts, in its own way, warns that failing to engage with the non-classical dimension of mind—whether framed as the unthinkable, the quantum, or the unconscious—risks reducing intelligence to a computational schematic that excludes complexity, ambiguity, and the irreducible dimensions that psychoanalysis and deconstruction insist must be accounted for.

In what follows, I will preserve my earlier discussion of Plotnitsky’s complementarity while embedding it within a broader critique of reductionist-exclusionist tendencies at institutions like SFI.

Additionally, I will integrate further reflections on quantum mechanics, deconstruction, psychoanalysis, and Jacques Lacan’s four discourses (the master, the university, the analyst, and the hysteric), exploring how these frameworks help us uncover the often unconscious—both cultural and individual—mechanisms through which both the thinkable and the unthinkable are dismissed, repressed, excluded, or silenced, only to resurface as a return of the repressed. While what is truly unthinkable remains beyond representation, what is rendered unacceptable or unspeakable within institutional contexts often reemerges in displaced or distorted forms, disrupting the very structures that sought to suppress it. In that sense, this essay itself hopes to enact a return of the repressed within institutions like SFI.

Unthinkable Intersections: Plotnitsky, Psychoanalysis, and Deconstruction

The intersection of quantum mechanics, deconstruction, and psychoanalysis is not an obvious one. Yet Arkady Plotnitsky’s work demonstrates how these seemingly distinct fields share a fundamental concern with the limits of knowledge—what can be thought and what remains unthinkable. In his paper The Thinkable and the Unthinkable in Psychoanalysis and Philosophy, From Sophocles to Freud to Derrida, Plotnitsky argues that psychoanalysis and deconstruction engage with an irreducibly unthinkable dimension, just as quantum physics confronts the impossibility of fully conceptualizing matter at its most fundamental level.

On the surface, quantum theory—with its abstract mathematics and paradoxical findings—might appear far removed from Derridean deconstruction or Freudian-Lacanian psychoanalysis. But Plotnitsky shows that each of these fields encounters a point of limit, a zone beyond which established categories and rationalist frameworks fail us. Deconstruction exposes the deferrals of meaning in language; psychoanalysis faces the unknowable core of the unconscious; and quantum mechanics grapples with phenomena that cannot be fully described in classical terms.

One question that arises: Does the Santa Fe Institute, known for its broad engagement with “complexity,” truly engage with quantum mechanics in a way that challenges classical conceptions of knowledge? While SFI certainly acknowledges complexity at macroscopic and computational levels, it often does so in ways that remain grounded in rationalist approaches to modeling. Plotnitsky’s focus on quantum complementarity, and his insistence that modern physics itself defies classical rationality, suggests that any comprehensive philosophy of science must account for quantum principles—and not simply treat them as anomalies that can be contained within a classical or semi-classical approach.

Plotnitsky’s Complementarity and the Limits of Thought

Plotnitsky develops the concept of complementarity from Niels Bohr’s quantum mechanics, where wave-particle duality presents a paradox: electrons and photons exhibit mutually exclusive behaviors depending on how they are observed. Rather than resolving this contradiction, Bohr argued that both descriptions are necessary but irreconcilable. Plotnitsky extends this insight into the realm of philosophy and psychoanalysis, where concepts such as the unconscious, différance, and non-classical ontology similarly require complementary yet irreconcilable perspectives.

At SFI, researchers often adopt frameworks that rely on classical reasoning about systems, especially in cognitive science and AI contexts. Plotnitsky, drawing on Bohr, points out that genuinely complementary perspectives cannot be synthesized into a single, totalizing picture. Moreover, because Plotnitsky is a Distinguished Professor of Philosophy and Literature with a solid grounding in both scientific and humanistic discourses, he underscores that quantum mechanics is not a peripheral curiosity; it challenges the very epistemic assumptions that mainstream American psychology and analytic philosophy take for granted:

1. The Unthinkable in Psychoanalysis. Freud’s das Unbewusste (the unconscious) represents the unknown, but not necessarily the unthinkable. However, Plotnitsky suggests that at its deepest level, the unconscious moves toward what he calls non-classical ontology—a space where concepts like Being or thought become fundamentally inapplicable. In psychoanalysis, we do not merely map hidden drives; we discover that certain dimensions of mind resist all classical conceptualization.

2. Deconstruction and the Unthinkable. Derrida’s concept of différance is similarly unthinkable in the classical sense. It is neither a thing nor an absence but a constitutive delay that makes meaning possible while ensuring that meaning is never fully present. This aligns with Plotnitsky’s claim that psychoanalysis and deconstruction encounter the same epistemological crisis as quantum physics—namely, the inability to fully capture reality through stable concepts.

3. Non-Classical Epistemology. Just as Bohr rejected classical determinism in physics, Plotnitsky argues that Freud and Derrida reject the idea that the mind, language, or meaning can be fully systematized. This is a direct challenge to traditional analytic philosophy and behavioral psychology, which often assume that intelligence and cognition can be rationally described, modeled, or computed.

Despite its prominence in addressing “complexity,” the Santa Fe Institute remains grounded in a tradition that cannot fully accommodate non-classical ontology. Researchers may discuss emergent properties, agent-based modeling, or statistical complexities, but the deeper, more unsettling insights of quantum mechanics—its refusal of classical coherence—are often glossed over or marginalized. As a result, SFI’s “hybrid” approach can default back to rationalist methods, leaving unexamined the possibility that intelligence (human or otherwise) might intrinsically defy full calculation.

Overlaps with Complexity, Psychoanalysis, and Deconstruction

Plotnitsky’s perspective highlights that complexity science, psychoanalysis, and deconstruction may have more in common than is typically acknowledged—particularly at places like the Santa Fe Institute, which could benefit from these insights. Because these disciplines grapple with irreducible limits, they challenge the assumption—still prevalent in American psychology and analytic philosophy—that everything meaningful about cognition can be rendered in computable or rational terms.

The Incompleteness of Knowledge

One of the most striking connections between Plotnitsky’s work and complexity science is the idea of ontological incompleteness. Plotnitsky’s non-classical ontology states that the ultimate nature of thought, matter, or Being is systematically beyond our grasp.

• Quantum Mechanics & Gödelian Incompleteness. Gödel’s incompleteness theorems and Turing’s halting problem reveal intrinsic limits within formal logical systems—limits that are structurally similar to the epistemic gaps in quantum physics and psychoanalysis. Where quantum physics reaches a limit in measurement and representation, Gödel’s logic and Turing’s computation show analogous limits in mathematics and computer science.

• Psychoanalysis. Freud initially believed that the unconscious could be systematically mapped, but as psychoanalysis evolved, figures like Lacan and Derrida pushed the idea that the unconscious operates at the level of the unthinkable—it is not just unknown, but unknowable in principle. This unknowable core challenges a purely systematic or classical view of the psyche.

• Deconstruction. Derrida’s différance suggests that meaning is always deferred, preventing a final grounding of knowledge. In Plotnitsky’s terms, this is a non-classical epistemology, where meaning functions like a quantum phenomenon—always shifting based on context, never fully present.

Attempts to systematize human intelligence or consciousness into strict rational models (such as AI cognition models or neuro-reductionist frameworks) will always encounter structural limits that evade reduction. Recent discussions in the blog posts “Incompleteness, the Unconscious, and the Supplement: Toward an Ethics of Cyborgian Care” and “When Philosophy and Psychology Seek a Rational-Calculable Mind—and Why Deconstruction and Psychoanalysis Resist” similarly emphasize these structural limits. Both highlight how ignoring these “unthinkable” dimensions leads to ethical and conceptual blind spots, such as failing to appreciate the role of care, subjectivity, and creativity in complex systems.

Complementarity in Mind and Meaning

Another major overlap is the idea of complementarity in psychology and deconstruction:

• In Psychoanalysis. Freud’s model of the split subject suggests that our thoughts and desires are structured by complementary but contradictory forces (e.g., conscious/unconscious, repression/expression). This resonates with quantum complementarity, where the subject of psychoanalysis is never fully one thing or the other but exists in a paradoxical interplay of presence and absence.

• In Deconstruction. Derrida’s notion that meaning is never fully “here” but always deferred can be understood in light of quantum superposition—where a system exists in multiple states until it is observed. Derrida and Plotnitsky both highlight the non-classical nature of signification, where meaning is relational, unstable, and undecidable.

• In Complexity Science. Much like psychoanalysis and deconstruction, complex systems do not resolve into a singular mode of explanation. The interaction of multiple forces—feedback loops, emergent behaviors, unpredictability—means that any attempt to construct a totalizing “rational-calculable” model of intelligence will always be incomplete.

The implication here is profound: if psychoanalysis and deconstruction share a similar structure with quantum mechanics and complexity science, then attempts to create a fully computable model of human intelligence (such as AI-based theories of mind) are fundamentally flawed. The mind is not a machine because intelligence is entangled with the unthinkable—it cannot be reduced to a set of formal rules or algorithms.

Yet this recognition is largely absent from mainstream SFI discussions, which tend to fold “complexity” back into a rational framework rather than confront its unthinkable aspects head-on. Even if SFI does include quantum mechanics in its portfolio of scientific interests (and it does, in certain contexts, explore quantum computing and quantum biology), the question is whether it embraces the radical epistemological implications of quantum theory—that is, the end of classical realism and classical determinism that Plotnitsky, Derrida, and Lacan highlight. Merely studying quantum phenomena from a vantage of classical reason fails to challenge the underlying rationalist premises about the mind.

Lacan’s Discourses and the Denial of the “Unthinkable”

In order to see how “the unthinkable” tends to be repressed or denied in institutional contexts, it is helpful to bring in Jacques Lacan’s four discourses: the Discourse of the Master, the Discourse of the University, the Discourse of the Hysteric, and the Discourse of the Analyst. In Lacan’s schema, the “university discourse” privileges official knowledge, systematization, and a quest for mastery through epistemic frameworks. It stands opposed, in many ways, to the “discourse of the hysteric,” which disrupts these frameworks by introducing questions or demands that the system cannot readily handle.

• Discourse of the Master: Strives to impose order and mastery, avoiding contradictions that might threaten authority.

• Discourse of the University: Pursues knowledge in an institutionalized form, often ignoring or dismissing what it cannot incorporate into its rational apparatus.

• Discourse of the Hysteric: Voices the irreducible question, the cry, or the irrepressible contradiction that unsettles the Master or the University’s knowledge-claims.

• Discourse of the Analyst: Seeks to facilitate transformations in subjectivity, but it, too, can become a system that might fail to apprehend what truly unsettles classical thinking—thus itself being “challenged” by certain forms of the unthinkable.

Quantum mechanics, the Freudian unconscious, and Derridean différance all appear—within the “discourse of the university” or “discourse of the master”—as forms of the “hysteric’s discourse”: they represent that which refuses to be mastered or neatly integrated into rational systems. Indeed, sometimes even the discourse of the analyst (psychoanalysis itself) tries to “master” the unconscious, but is continually faced with elements that defy any final interpretive closure. This is precisely the dynamic that Plotnitsky traces when he argues that each of these fields reaches a point of irreducible unthinkability.

American psychology, steeped in behaviorism and cognitive science, frequently enacts the discourse of the university in Lacan’s sense: it “denies the truth of the unconscious” or relegates it to something purely fictional or metaphorical, because acknowledging the unconscious as a site of unthinkable processes would destabilize the neat boundaries of rationalist epistemology. In a parallel manner, certain strains of philosophy of science might marginalize quantum mechanics—or interpret it in purely classical terms—because its deeply non-classical nature collides with a worldview that insists knowledge can (and should) be wholly transparent and computable.

Toward an Anti-Epistemology of Mind

If Plotnitsky’s insights are correct, we are led toward something like an anti-epistemology—a stance that does not seek to conquer or resolve the unthinkable, but rather to recognize it as constitutive. Rather than treat this dimension as a problem to be solved, we might think of it as the productive core of creativity, ethics, and genuine thought.

Why This Challenges Analytic Philosophy and Cognitive Science

Analytic philosophy and mainstream cognitive science operate under a classical ontology that assumes thought can be formalized, modeled, and ultimately systematized. However, if intelligence operates according to non-classical principles, then these models are structurally incapable of capturing the essence of consciousness.

• Kurzweil’s Singularity is a Myth. If human intelligence cannot be fully represented in classical models, then the comparison between AI and human cognition collapses. Kurzweil’s singularity assumes that intelligence is computable, but Plotnitsky’s work suggests that human thought includes an “unthinkable” dimension that AI can never replicate.

• The Limits of Behavioral Science. Behavioral psychology operates on predictable models of cognition, but Plotnitsky’s insights show that cognition includes fundamental unpredictabilities. Much like quantum measurement, the moment you attempt to formalize thought, it changes in response.

From an anti-epistemological perspective, the project of fully modeling the mind—be it through neural nets, symbolic logic, or behaviorist frameworks—will inevitably reach a horizon beyond which it cannot venture. Quantum mechanics, if seriously engaged, would reinforce this horizon, insisting that not all phenomena can be pinned down through classical cause-and-effect or purely rational rules.

Ethics of the Unthinkable and an Invitation to Reorient Research

Plotnitsky’s insights also have ethical implications. If thought is fundamentally open-ended and non-classical, then any system that attempts to totalize human intelligence risks imposing artificial constraints on subjectivity. Recognizing the irreducibility of mind leads to an ethics of incompleteness—an acknowledgment that true care, creativity, and intelligence emerge precisely where systematization fails.

Such an ethics resonates with the arguments in “Incompleteness, the Unconscious, and the Supplement: Toward an Ethics of Cyborgian Care,” which stresses that care emerges from confronting the inherent incompleteness of systems—be they biological, psychic, or computational. It’s also echoed in psychoanalytic practice, which knows that healing and insight often arise not from strict rationalization but from engaging the unthinkable depths of psychic life. Indeed, in an institutional landscape like SFI, where the emphasis is often on forging universal models of complexity, the ethical invitation would be to hold open that space for what cannot be reduced, measured, or stabilized.

From a Lacanian perspective, we might say that acknowledging the “hysteric’s discourse” within institutional science means validating the disruptive questions that refuse to be integrated into a neat knowledge-system. Rather than automatically relegating quantum indeterminacy, the unconscious, or différance to mere by-products of scientific or philosophical exploration, a truly interdisciplinary approach would treat them as essential components of our understanding of mind, matter, and meaning.

Conclusion: An Urgent Challenge to the Santa Fe Institute’s Approach

Plotnitsky’s complementarity bridges quantum physics, psychoanalysis, and deconstruction in a way that profoundly challenges our understanding of intelligence, cognition, and meaning. By recognizing non-classical epistemologies, we see that human intelligence is irreducibly complex, entangled with the unthinkable, and fundamentally beyond mechanization.

For the Santa Fe Institute, which prides itself on being at the forefront of complexity research, this offers both a provocation and an opportunity. The question is whether SFI—despite its occasional forays into quantum subjects—truly embraces the deeper implications of non-classical physics for models of mind and cognition. If it does not, then it risks reclassifying complexity as just another computational variable. If the rational-epistemological framework holds unchallenged, the unthinkable dimension that Plotnitsky, Freud, Derrida, and Lacan illuminate—the aspect of mind that is not wholly rationalizable—will be sidelined.

In effect, attempts to fully formalize intelligence will always leave something out—something unthinkable yet foundational to what makes us human. If SFI aims to be genuinely interdisciplinary, it would do well to confront these findings head-on, rather than assume that complexity can be neatly absorbed into a classical system. As the two blog posts referenced here also emphasize, the unthinkable is not a gap to be filled but a constitutive feature of thought, ethics, and care. Instead of dismissing psychoanalysis, deconstruction, or the radical epistemological implications of quantum mechanics, SFI might incorporate their insights, enriching its theories of complexity with the recognition of a crucial limit—one that does not confine us but, rather, opens thinking (and ethics) to new horizons.

Ultimately, the conversation initiated by Plotnitsky’s work represents a call to reimagine what “understanding” means, be it in physics, philosophy, psychoanalysis, or the emerging frontier of AI. The very structures of knowledge explored at the Santa Fe Institute—networks, adaptive systems, agent-based models—may gain depth if they recognize that not everything about mind and matter can be captured in a single coherent framework. Recognizing the necessity of complementary but irreducible perspectives, and embracing the genuinely unthinkable at the core of intelligence, might well be the leap that carries us beyond the limitations of purely rationalist science.

It is precisely in that leap—where psychoanalysis, deconstruction, and quantum mechanics converge—that a more profound, ethically informed, and truly non-classical notion of mind can emerge. And it is precisely there that any institution claiming to study the frontiers of complexity should be willing to follow, acknowledging that the “discourse of the hysteric” remains essential for keeping our understanding open, flexible, and radically alive.