Tanmoy Bhattacharyya on Consciousness: Biology, Psychology & Philosophy

An Introduction to Consciousness

The phenomenon we call consciousness (1) is the only datum that is simultaneously self-evident and theoretically recalcitrant. It is the luminous, first-person fact of being someone for whom something appears—red as red, pain as hurt, thought as thought, self as self—while every attempt to locate this interiority within the objective order of nature ends either in reductive collapse or in the postulation of an unbridgeable chasm. No other topic in human inquiry has generated a wider divergence of explanatory registers, each claiming exclusive legitimacy, each internally coherent, yet each radically incommensurable with the others.

Contemporary systems neuroscience, armed with intracranial recordings, optogenetics, and perturbational complexity measures, has mapped the minimal neural signature of reportable experience to sustained, feedback-dependent, gamma-range dynamics in a posterior cortical hot zone, modulated by thalamic gating and prefrontal amplification. Predictive-coding frameworks and global neuronal workspace models converge on the claim that conscious contents are the winning perceptual hypotheses broadcast across a frontoparietal network after recurrent processing has resolved ambiguity.

Anesthesia, from propofol’s GABAergic hyperpolarisation to ketamine’s NMDA blockade, demonstrates that these same dynamics can be extinguished or dissociated with exquisite pharmacological precision, producing states in which rich cortical activity persists yet no one is home, or in which a dissociative hyper-clarity emerges without a coherent self. The return of consciousness on emergence follows a stereotyped sequence—auditory vigilance first, then vision, then narrative self—suggesting a hierarchical reassembly along phylogenetically conserved lines.

Evolutionary and developmental biology reveal that the capacity for phenomenal experience is not a late human acquisition but a graded continuum. Minimal sentience appears as early as the vertebrate mesodiencephalic core; thalamocortical recurrence, the posterior hot zone, and affective valence emerge in parallel across fish, reptiles, birds, and mammals. In human ontogeny, discontinuous EEG yields to continuous patterns around 28–30 weeks of gestation, the default-mode network begins its anti-correlation with task-positive systems in the third trimester, and the slow maturation of prefrontal–posterior connectivity tracks the gradual emergence of reflective self-awareness. The distribution question—where along the phylogenetic and ontogenetic axes experience begins—remains open, but the once-sharp line between conscious and unconscious biological systems has dissolved into a spectrum.

Cognitive psychology and experimental phenomenology have dismantled the myth of a transparent, unitary consciousness. Attention and awareness dissociate in inattentional blindness, change blindness, and partial-report paradigms; higher-order theories, recurrent-processing accounts, and illusionist eliminations compete to explain why some mental states feel like something while most do not. Trained introspection in micro-phenomenology and long-term meditation reveals pre-reflective strata of experience invisible to the untrained subject, while psychedelic compounds and deep hypnotic suggestion demonstrate that the contents, boundaries, and very texture of consciousness are under direct top-down linguistic and pharmacological control. In the hypnotic state, agency, identity, pain, colour, memory, and time can be installed, removed, or inverted by verbal suggestion alone, revealing the self-model as a high-level, editable construct and phenomenal binding as a prefrontal achievement rather than a sensory given.

Western philosophy, from the pre-Socratics to twenty-first-century analytic debates, has oscillated between treating consciousness as the essence of reality (Parmenides, Plato, Augustine, Descartes, Leibniz, Kant, Husserl) and attempting to reduce it to physics, function, or illusion (Democritus, Hobbes, behaviourism, identity theory, functionalism, illusionism). The hard problem, the explanatory gap, zombie arguments, knowledge arguments, and the modal force of conceivability have kept dualism and non-physicalist realism alive despite the closure instincts of scientific naturalism. Russellian monism, neutral monism, and constitutive panpsychism have re-entered the arena as serious options, while strong illusionism continues to insist that the datum itself is the mistake.

Indian darśanas, by contrast, never granted matter or mind ontological primacy. From the Upaniṣadic neti-neti to Śaṅkara’s anirvacanīya-māyā, Patañjali’s puruṣa-prakṛti dualism, Abhidharma’s moment-by-moment vijñapti, Yogācāra’s ālaya-vijñāna, and Abhinavagupta’s spanda-śakti, consciousness (cit, chaitanya, ātmā, śiva) is the sole self-luminous reality; body, world, and ego are subsequent appearances within it. Liberation (Moksha) is not the production of a new state but the removal of a false limitation through direct recognition (pratyabhijñā, vidyā, jñāna). The hard problem does not arise because the premise that non-conscious matter is foundational is rejected from the outset.

Near-death experiences, occurring during documented cardiac arrest with flat EEG, absent brainstem reflexes, and no cerebral blood flow, present the most dramatic empirical challenge to production models. Veridical out-of-body perception, enhanced lucidity, life review, encounter with an unconditional loving presence, and transformative after-effects have been prospectively documented in modern resuscitation settings. These phenomena occur precisely when every known neural correlate of consciousness is absent or catastrophically degraded, forcing a confrontation with the possibility that the brain normally constrains, filters, or localises a more fundamental field of sentience rather than generating it ex nihilo.

Taken together, these registers—neuroscience, evolutionary biology, cognitive psychology, hypnotic and pharmacological alteration, Western metaphysics, Indian soteriological ontology, and the extremity of clinical death—do not converge. They form a prism in which the same phenomenon is refracted into mutually irreducible images: a late-stage biological process, a predictive inference engine, a controlled hallucination, a top-down editable story, an immaterial substance, a transcendental condition, the sole self-evident reality, or a non-local field momentarily liberated from neural constraint. Each register is internally rigorous, empirically grounded in its own domain, and yet the translation manual between them remains unwritten.

Are Consciousness and Mind the Same or Different?

The short, accurate, and therefore frustrating answer is: it depends on who is speaking, in which tradition, and at which moment in history.

In ordinary English and in most contemporary philosophy of mind, “mind” and “consciousness” are used in overlapping but non-identical ways:

• “Mind” is the broader term. It typically includes everything mental: conscious experiences, unconscious beliefs and desires, dispositions, perceptual processing that never reaches awareness, implicit biases, procedural skills, repressed memories, the machinery of attention, and (for many theorists) the functional architecture that could in principle be replicated in silicon.
• “Consciousness” is the narrower term. It refers specifically to phenomenal consciousness (from the Greek phainomenon = that which appears): there being something it is like to be a system, the subjective, qualitative, first-person “what-it-feels-like” dimension. Pain as hurt, red as red, the taste of coffee, the felt sense of self, the raw presence of a thought—these are paradigmatic of phenomenal consciousness.

Under this now-standard terminology (largely fixed by Nagel 1974, Block 1995, and Chalmers 1996), mind and consciousness are decisively not the same:

• A very large part of the mind is unconscious (Freud’s iceberg, modern cognitive science’s massive parallel processing, subliminal priming, blindsight, masked semantic activation, implicit attitudes, etc.).
• It is at least conceivable (and for many philosophers logically possible) that a system could have a full-blown mind—beliefs, desires, memories, sophisticated information-processing—yet be a perfect zombie: no phenomenal consciousness whatsoever.
• Conversely, it is possible (though controversial) that some simple systems have phenomenal consciousness without anything resembling a human-style mind (e.g., the “minimal phenomenal experience” some panpsychists or IIT proponents attribute to very simple organisms or even sub-personal neural coalitions).

So, in the dominant late-20th- and 21st-century Anglophone philosophy of mind and cognitive science: mind ⊃ consciousness; consciousness is a proper subset (perhaps a very peculiar proper subset) of mind.

However, this tidy distinction dissolves the moment one steps outside the post-1950 analytic tradition:

• In classical Indian philosophy (all darśanas), the everyday word that is usually translated as “mind” is manas or antaḥkaraṇa. Manas is emphatically not consciousness itself. Manas is the inner organ that fluctuates, produces thoughts, desires, memories, and ego-sense; it is part of prakṛti (the unconscious, ever-changing matrix). Pure consciousness (cit, puruṣa, ātmā, caitanya, śiva, vijñapti-mātra in Yogācāra) is the unchanging witness of manas, not identical with it. Here, consciousness is categorically different from and ontologically prior to mind.
• In classical Western philosophy before the 20th century, “mind” (Latin mens, Greek nous, psychē) is almost always closer to what we now call consciousness than to the broad functional notion. For Descartes, the essence of mind is thinking, and all thinking is conscious (he explicitly denies unconscious mental states). For Locke, Berkeley, Hume, and Kant, “mind” is essentially the theatre of experience. Unconscious mentality is a late 19th-century (Leibniz–Hartley–Herbart–Freud) discovery.
• In much Buddhist psychology (especially Abhidharma and Yogācāra), vijñāna (consciousness) arises moment by moment and is not a persisting substance, but it is still the luminous-cognitive aspect; the cetasikas (mental factors) and the underlying tendencies are sometimes treated separately.
• In everyday German idealism and phenomenology, Geist, Bewusstsein, and Erlebnis are used in ways that make “mind” and “consciousness” virtually synonymous.
• In contemporary “4E” (embodied, embedded, extended, enactive) cognitive science and some neurophenomenological circles, the very distinction is questioned: consciousness is not a private inner glow but the organism–environment coupling itself; “mind” is not inside the head, so the contrast loses its bite.

Therefore, the apparently simple question “Are consciousness and mind the same?” has no context-free answer. It has at least five historically major answers:

1. Analytic philosophy of mind 1970–2025: No. Mind is broader; consciousness is the hard part.
2. Classical Indian darśanas: No. Consciousness is the unchanging subject; mind is the changing object illuminated by consciousness.
3. Classical Western philosophy (Descartes to Kant): Effectively yes. Mind = the realm of conscious thought and experience.
4. Freudian and post-Freudian depth psychology: No. Most of mind is unconscious; consciousness is the thinnest surface layer.
5. Radical enactive/phenomenological/idealist views (late Varela, some readings of Merleau-Ponty, certain non-dual traditions): The distinction itself is an artefact of a mistaken representationalist framework.

My lectures will not resolve the terminological issue; they will instead display why the question can be framed in such irreconcilable ways. The Western tradition largely treats consciousness as a puzzle inside the mind or inside the world. The Indian tradition treats the mind (Manas and Chitta) and world as puzzles inside consciousness. Neuroscience and cognitive science treat both mind and consciousness as natural phenomena to be tracked with ever-finer tools. The confrontation between these perspectives is not a prelude to synthesis; it is the living drama of the field itself.

Structures of the Lectures

The first five lectures were commissioned to survey the contemporary intellectual landscape of this single phenomenon from five distinct, mutually irreducible angles:

1. Contemporary systems neuroscience (the biological mechanisms that correlate most tightly with the presence and specific contents of experience).
2. Evolutionary and developmental neurobiology (the deep history and gradual emergence of sentience across living forms and across the human lifespan).
3. Psychological and cognitive-science approaches (the functional role of consciousness, its relation to attention, reportability, metacognition, and its systematic experimental investigation), in two parts.
4. Western philosophical perspectives from the pre-Socratics to late-2025 analytic philosophy of mind (the 2,600-year attempt to locate consciousness inside or outside the physical order).
5. Indian philosophical systems from the Upaniṣads to Kashmir Shaivism (the millennium-and-a-half-long insistence that consciousness is not a puzzle to be solved but the sole reality in which every puzzle appears).

Additional lectures will inquire:

(6) Consciousness in the Light of Hypnotic Trance and Suggestion

(7) Consciousness under general anesthesia

(8) Consciousness during clinical death (NDEs)

Again, my lectures that follow do not promise resolution, and the ‘consciousness’ has nothing to do with religion or religious experience; therefore, I intentionally avoided mentioning it. They stage the confrontation itself, allowing the full force of each perspective to be felt without premature harmonisation. For if consciousness (Chaitanya in sanskrit) (2) is the place where the objective and subjective orders meet, then any adequate account must eventually explain not only how neurons produce experience but how experience produces the very concept of neurons, how the apparent many return to the real One, and how a heart that has stopped beating can nevertheless become the occasion for the most vivid awakening a human being has ever known. Until that explanation arrives—if it ever can—the phenomenon remains what it has always been: the clearest thing we know and the deepest enigma we face.

Tanmoy Bhattacharyya

29th November 2025

(1) Consciousness is the most certain fact any of us will ever encounter and, simultaneously, the most obstinate mystery that human thought has ever faced. You are reading these words right now, and in that very act, there is something it is like to be you: colours appear, meanings dawn, perhaps a faint bodily sensation of sitting or standing, maybe a background hum of emotion or memory. None of this is hypothetical, none of it is inferred; it is the ground on which every hypothesis and every inference rests. Yet the moment we try to say what this luminous presence actually is, where it comes from, or how it relates to the 86 billion neurons firing inside a skull, language falters and metaphysics divides into irreconcilable camps.

(2) For the Yoga Sutra of Patanjali, Consciousness is the expansion of Chitta.