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Integrated Information Theory vs Nagel’s Mind and Cosmos

Integrated Information Theory (IIT) and Nagel's Mind and Cosmos, compared field by field from their entries in the Atlas.

At a glance

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The claim

In brief
Integrated Information TheoryIIT is an original, radical model that proposes a definition for conscious experience and specifies which physical systems can possess it, starting from the phenomenology of consciousness (axioms). It translates these axioms into physical postulates based on intrinsic cause-effect power, featuring a mathematical measure Φ(Phi) to quantify a system's capacity for informational integration, which correlates with the degree of consciousness.
Nagel’s Mind and CosmosThis perspective challenges the prevailing materialist Neo-Darwinian conception of nature, arguing that it fails to account for the irreducible nature of subjective experience, or 'what it is like' to be a conscious organism. It proposes that mind must be incorporated as a fundamental principle of nature itself.
What consciousness is
Integrated Information TheoryConsciousness is identified as a Φ-structure, a maximally reduced conceptual structure existing in 'qualia space'. An experience is identical to this conceptual structure, meaning its phenomenal properties correspond precisely to the physical properties of the cause-effect structure unfolded from the physical substrate of consciousness (PSC).
Nagel’s Mind and CosmosConsciousness is fundamentally subjective experience—'how it is for the subject himself'—which resists reduction to purely physical, third-person descriptions.

Big questions

Integrated Information TheoryNoKoch, a proponent, argues that consciousness is not computable. Digital computers have negligible integrated information (Φ(Phi)) due to hardware structure, meaning they can never be sentient, regardless of intelligence.
Nagel’s Mind and CosmosUncertainAs a critique of functionalism and reductionism, Nagel's view suggests that purely computational entities lacking fundamental mental properties are likely philosophical zombies; outcome depends on whether future AI can instantiate the hypothesized universal mental principles.
Integrated Information TheoryUncertainIf phenomenal consciousness requires a radically new structure (like IIT's postulates), the potential permanence of these 'inscrutable things' cannot be rejected, leaving the possibility of survival open, even though IIT does not explicitly espouse life after death.
Nagel’s Mind and CosmosConditionalIf consciousness is a universal, fundamental property rather than a biological emergent, its essence may persist after bodily dissolution (inferred from panpsychist leanings), though likely without retention of personal identity.
Integrated Information TheoryNoIf consciousness is a fundamental property tied to real cause-effect power, a digital simulation (uploading) would only create a 'perfect zombie'—an entity that acts like the original but lacks subjective consciousness—because the simulation is virtual, lacking the required real cause-effect power.
Nagel’s Mind and CosmosUnlikelyThe irreducibility of subjective experience means duplication of physical/functional patterns alone would fail to transfer the original first-person consciousness.
Integrated Information TheoryUncertainWhile the measurement and analysis of consciousness do not convey ultimate meaning, the speculative nature and novelty of the innumerable nth dimensional conceptual structures (conscious percepts) warrants suspending judgment on ultimate meaning/purpose/value.
Nagel’s Mind and CosmosCosmic/UltimateExplicitly seeks to incorporate mind as a fundamental natural principle to overcome the 'pointlessness' implied by materialism, suggesting a non-theistic, inherent cosmic purpose or value.

Nature of mind

Ontology
Integrated Information TheoryIIT's fundamental ontology is the ontological primacy of phenomenal existence, based on an intrinsic powers view where what truly exists in physical terms are intrinsic entities capable of cause and effect. Koch notes that the theory insists consciousness must be incorporated into the basic description of reality at the rock-bottom level.
Nagel’s Mind and CosmosPhilosophical Challenge (leaning towards Universal Monism/Panpsychism)
Mind and body
Integrated Information TheoryIIT asserts an explanatory identity: an experience is identical to a Φ-structure. It contends that the conscious entity is the Φ-structure expressing its causal powers, not the neural substrate itself. This framework leaves no room for emergence or dualism.
Nagel’s Mind and CosmosCritiques the current conception of the mind-body relationship, asserting that we lack any conception of how physical and phenomenological aspects could be related or identical.
Fundamental or emergent
Integrated Information TheoryConsciousness is defined by intrinsic existence and characterized as belonging to the basic description of reality. The theory rejects emergence.
Nagel’s Mind and CosmosPrimitive (or fundamental)
Qualia
Integrated Information TheoryDistinct conscious experiences are conceptual structures in a 'qualia space'. The qualitative feel (phenomenal properties) corresponds one-to-one to the physical properties of the maximally irreducible cause-effect structure, which is also called a quale.
Nagel’s Mind and CosmosQualia (felt qualities) are the core of the problem, and Nagel argues that no objective or physicalist explanation currently formulated can account for their subjective reality.

How it works

Mechanism
Integrated Information TheoryThe core principle is Integrated Information (Φ(Phi)), which quantifies the system's irreducibility. The Exclusion Postulate ensures that only the maximally irreducible cause-effect structure (the Φ-structure) exists intrinsically, defining the boundaries and grain of consciousness.
Nagel’s Mind and CosmosPrimarily focuses on exposing the conceptual limits of physical reductionism rather than positing a definitive mechanism. Mechanistically, his solution suggests consciousness arises through the composition of fundamental, panpsychic-like elements.
Where it is
Integrated Information TheoryConsciousness is not limited to biological brains. IIT predicts the conscious structure resides in the posterior cortex (occipital, parietal, and temporal cortices). Systems with maximally irreducible intrinsic cause-effect power possess consciousness.
Nagel’s Mind and CosmosUniversal/Systemic (inferred from universal monism/panpsychism leanings) or inherent in the fabric of nature.
What it does
Integrated Information TheoryConsciousness is identified as unfolded intrinsic causal power, which is the ability to effect change. Only this intrinsic entity (the Φ-structure) can cause, supporting the claim that true free will exists for systems with high Φ(Phi).
Nagel’s Mind and CosmosPrimarily critical, arguing against the materialist view that consciousness is an inert epiphenomenon. If mind is a fundamental principle, it implies an irreducible, organizing role in the cosmos.

Evidence and criticism

Testability
Integrated Information TheoryIIT claims scientific testability, employing quantitative measurement. However, critics argue that the theory is not truly empirically tested, and its core predictions may be idiosyncratic.
Nagel’s Mind and CosmosUncertain/Primarily Conceptual. The theory's strength lies in its diagnosis of the explanatory gap, not in empirical verification. His suggested alternative (panpsychism) is highly speculative.
Tests so far
Integrated Information TheoryCalculating Φ(Phi) for specific neural networks (e.g., visual cortex).,Monitoring brain activity as subjects slip into anesthesia.,Adversarial collaboration experiments testing predictions about sustained activity in the posterior cortex.
Nagel’s Mind and CosmosNot stated
Criticisms
Integrated Information TheoryThe theory faces criticism for anti-common sense predictions (imputing consciousness to simple objects). A public letter characterized IIT as 'pseudoscience'. Critics challenge that experiments test only idiosyncratic predictions and not the core metaphysical ideas. Chalmers noted the 'pseudoscience' label was disproportionate and caused vast collateral damage.
Nagel’s Mind and CosmosCriticized for retreating to 'mysterianism' and for rejecting established scientific frameworks (Neo-Darwinian materialism) without offering a concrete, robust, and detailed secular ontology as an alternative.

Sources

Key sources
Integrated Information Theory
  • From the phenomenology to the mechanisms of consciousness: integrated information theory 3.0, Oizumi, Albantakis, Tononi (2014)
  • Consciousness: here, there and everywhere?, Tononi and Koch (2015)
  • Only what exists can cause: an intrinsic powers view of free will, Tononi et al. (2022)
Nagel’s Mind and Cosmos
  • What Is It Like to Be a Bat? (1974)
  • The View from Nowhere (1986)
  • Mind & Cosmos: Why the Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False (2012)

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