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Emergence vs Integrated Information Theory

Emergence (Principle of Consciousness) and Integrated Information Theory (IIT), compared field by field from their entries in the Atlas.

At a glance

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Materialism Emergence (Principle of Consciousness) David Chalmers, Paul Davies, George Ellis
Information Integrated Information Theory (IIT) Giulio Tononi, Christof Koch

The claim

In brief
EmergenceEmergence is the philosophical claim that qualitatively new properties, such as consciousness or psychological states, arise from underlying physical properties governed entirely by physical laws. It is distinguished primarily into weak emergence, which is reducible in principle, and strong emergence, which is fundamentally non-reducible and may necessitate new physical laws.
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.
What consciousness is
EmergenceConsciousness is identified as a qualitatively novel property or psychological state arising from physical properties. This concept defines the relationship between mind and matter based on reducibility or non-reducibility to fundamental physics.
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).

Big questions

EmergenceConditionalIf consciousness is weakly emergent, AI consciousness is certain given sufficient complexity. If strongly emergent, AI consciousness is still possible if non-physical properties emerge from non-biological physical complexity, depending on the meta-psychophysical laws involved.
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.
EmergenceConditionalWeak emergence, being close to Materialism, precludes survival. Strong emergence, particularly in the form of Emergent Dualism, could theoretically generate a nonphysical substance (mind/soul) dependent on, but not strictly identical to, the physical brain, allowing for potential independent existence after death, although this is speculative.
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.
EmergenceConditionalIf consciousness is weakly emergent, duplicating the physical states would duplicate the mental states (likely). If strongly emergent, the non-reducible properties and possible downward causation would need to be perfectly captured and recreated in the new medium, posing significant, perhaps insurmountable, technical and conceptual challenges.
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.
EmergenceUncertainEmergence, especially strong emergence combined with concepts like top-down causation, offers a framework where higher-level properties like consciousness and its associated values could possess genuine causal power, potentially supporting cosmic purpose or meaning, depending on the resulting ontology.
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.

Nature of mind

Ontology
EmergenceHighly variable/Contested. Weak Emergence supports reductive Physicalism. Strong Emergence often implies Non-Reductive Physicalism or a need to expand the conception of nature, potentially requiring new fundamental laws (Naturalistic Dualism or Property Dualism).
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.
Mind and body
EmergenceEmergentist. The mind arises from the body (complex physical systems). The nature of the relationship depends on the type of emergence: Weak suggests reduction in principle; Strong suggests non-reducibility even in principle, often involving downward causation.
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.
Fundamental or emergent
EmergenceEmergent
Integrated Information TheoryConsciousness is defined by intrinsic existence and characterized as belonging to the basic description of reality. The theory rejects emergence.
Qualia
EmergenceQualia are the novel, qualitatively new properties (e.g., sensory qualities) that arise from the physical system. Strong emergence views consciousness (and thus qualia) as the clearest case of a strongly emergent phenomenon, fundamentally irreducible to underlying physical facts.
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.

How it works

Mechanism
EmergenceThe principle is the claim that novel, qualitatively distinct properties arise at higher levels of complexity, which is often contrasted with the reductive assumptions of mainstream science.
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.
Where it is
EmergenceTypically localized in complex biological systems (e.g., brains), although strong emergence proponents may argue that AI consciousness is possible if sufficient physical complexity is achieved, regardless of substrate.
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.
What it does
EmergenceVaries. Weak emergence aligns with standard physical causation. Strong emergence often posits top-down causation, where emergent higher hierarchical levels exert causal force on lower levels, giving the emergent property causal powers.
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).

Evidence and criticism

Testability
EmergenceSpeculative and philosophically contentious. Weak emergence is scientifically aligned in principle. Strong emergence is difficult to test empirically because it posits phenomena are non-deducible from fundamental science.
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.
Tests so far
EmergenceNot stated
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.
Criticisms
EmergenceIt is criticized by reductive physicalists (like Eliminative Materialists) as having little explanatory value, being superfluous, or acting as a 'restatement of a miracle' that fails to explain *how* unconscious complexity yields consciousness. Strong emergence specifically challenges the causal closure of the physical world.
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.

Sources

Key sources
Emergence
  • The Re-emergence of Emergence: the Emergentist Hypothesis from Science to Religion, P. Clayton and P. Davies (2008)
  • Strong and weak emergence, D. Chalmers (2008)
  • Why reductionism does not work, G.F.R. Ellis (2019)
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)

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