Head to head
Free Energy Principle vs Integrated Information Theory
Friston’s free-energy principle and active inference and Integrated Information Theory (IIT), compared field by field from their entries in the Atlas.
At a glance
- Free Energy Principle belongs to the Materialism family in Kuhn's Landscape of Consciousness, Integrated Information Theory to Information.
- On AI consciousness, Free Energy Principle says “Yes” and Integrated Information Theory says “No”.
- On life after death, Free Energy Principle says “No” and Integrated Information Theory says “Uncertain”.
- On mind uploading, Free Energy Principle says “Yes” and Integrated Information Theory says “No”.
- On meaning and purpose, Free Energy Principle says “Humanistic only” and Integrated Information Theory says “Uncertain”.
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The claim
In brief
Free Energy PrincipleThis theory conceptualizes consciousness as a natural process arising from the minimization of 'free energy,' which is the difference between an organism's internal model (perceptual expectations) and real-time sensory inputs. Consciousness, therefore, functions as the evolved mechanism for simulating scenarios of the world and reducing prediction error to ensure survival and maintain homeostasis.
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
Free Energy PrincipleConsciousness is identified as a natural process of inference, specifically the internal emergent model that monitors and minimizes the free energy principle (surprise), thereby optimizing the representational capacities of physical/brain systems.
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
Can AI be conscious?Differ
Free Energy PrincipleYesAs a strong materialist theory, if consciousness is fully explained by computational processes of inference and representation minimization, then non-biological systems capable of executing these processes must eventually attain consciousness in principle.
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.
Free Energy PrincipleNoConsciousness is an emergent natural process tied directly to the functional dynamics and physical substrate of the biological brain; thus, it cannot survive bodily decay.
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.
Free Energy PrincipleYesSince consciousness is understood as an emergent, formalized process of inference optimization, perfect duplication of the brain's information processing and representational dynamics in a non-biological medium should be sufficient for the continuation of the mental self.
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.
Free Energy PrincipleHumanistic onlyThe foundational imperative of the conscious process is survival (minimizing surprise/maintaining homeostasis). The theory does not rationalize ultimate cosmic meaning or purpose, aligning with general materialist perspectives.
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
Free Energy PrinciplePhysicalism; often referred to as Markovian Monism, which views mind/matter distinction as dialectical rather than ontological.
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
Free Energy PrincipleMonistic/Identity. The theory proposes that consciousness is the natural outcome of the physical/brain system's self-organizing processes, dissolving familiar dialectics between mind and matter.
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
Free Energy PrincipleEmergent
Integrated Information TheoryConsciousness is defined by intrinsic existence and characterized as belonging to the basic description of reality. The theory rejects emergence.
Qualia
Free Energy PrincipleThe theory is highly deflationary regarding the Hard Problem, treating consciousness as a process to be understood rather than a 'thing' whose qualitative attributes need definition. Qualia, if acknowledged, would be epiphenomena or aspects of the internal generative model required for inference.
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
Free Energy PrincipleThe Free-Energy Principle (FEP), which states that all self-organizing systems must minimize free energy (or 'surprise'), driving action and perception through active inference.
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
Free Energy PrincipleLocalized in the physical brain system; cortical responses are seen as the brain’s attempt to minimize free energy.
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
Free Energy PrincipleConsciousness serves an adaptive and functional role as the evolved mechanism for simulating scenarios, monitoring, and minimizing free energy to promote survival (homeostasis) and navigate the world.
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
Free Energy PrincipleConceptually and empirically linked to testable models (e.g., in neurobiology and psychology) through its reliance on formalizing representational capacities of physical systems.
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
Free Energy PrincipleThe principles of FEP form the basis for models utilized in empirical work concerning altered states (e.g., the Entropic Brain Hypothesis under psychedelics) and related theories of perception and cognition.
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
Free Energy PrincipleCriticized for being highly deflationary and difficult to reconcile with the first-person reality of phenomenal experience (the Hard Problem), viewing consciousness merely as a mathematical process or 'natural outcome.' Friston finds engaging with the philosophical premise of consciousness as a 'thing' difficult.
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
Free Energy Principle
- A theory of cortical responses, K. Friston (2005)
- Active interference: a process theory, K. Friston et al (2017)
- The Mathematics of Mind-Time, K. Friston (2017)
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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