Giulio Tononi's integrated information theory (IIT) proposes explaining consciousness by directly identifying it with integrated information. We examine the construct validity of IIT's measure of consciousness, phi (Φ), by analyzing its formal properties, its relation to key aspects of consciousness, and its co-variation with relevant empirical circumstances. Our analysis shows that IIT's identification of consciousness with the causal efficacy with which differentiated networks accomplish global information transfer (which is what Φ in fact measures) is mistaken. This misidentification has the consequence of requiring the attribution of consciousness to a range of natural systems and artifacts that include, but are not limited to, large-scale electrical power grids, gene-regulation networks, some electronic circuit boards, and social networks. Instead of treating this consequence of the theory as a disconfirmation, IIT embraces it. By regarding these systems as bearers of consciousness ex hypothesi, IIT is led toward the orbit of panpsychist ideation. This departure from science as we know it can be avoided by recognizing the functional misattribution at the heart of IIT's identity claim. We show, for example, what function is actually performed, at least in the human case, by the cortical combination of differentiation with integration that IIT identifies with consciousness. Finally, we examine what lessons may be drawn from IIT's failure to provide a credible account of consciousness for progress in the very active field of research concerned with exploring the phenomenon from formal and neural points of view.

To be true of every experience, the axioms of Integrated information theory (IIT) are necessarily basic properties and should not be “over-psychologized.” Information, for example, merely asserts that experience is specific, not generic. It does not require “access.” The information a system specifies about itself in its current state is revealed by its unfolded cause–effect structure and quantified by its integrated information.

Integrated information theory postulates that a conscious experience depends on a repertoire of hypothetical experiences (the axiom of information). This makes consciousness depend on the context that constrains the set of possibilities and on the scenarios imagined by the external observer, and not only on the system itself.

Consciousness directs the actions of the agent for its own purposive gains. It re-organises a stimulus-response linear causality to deliver generative, creative agent action that evaluates the subsequent experience prospectively. This inversion of causality affords special properties of control that are not accounted for in integrated information theory (IIT), which is predicated on a linear, deterministic cause-effect model. IIT remains an incomplete, abstract, and disembodied theory without explanation of the psychobiology of consciousness that serves the vital agency the organism.

We propose that measures of information integration can be more straightforwardly interpreted as measures of agency rather than of consciousness. This may be useful to the goals of consciousness research, given how agency and consciousness are “duals” in many (although not all) respects.

Doubtless, the conscious brain integrates masses of information. But declaring that consciousness simply “emerges” when enough has accumulated, doesn't really explain how first person experience is implemented by neurons. Moreover, empirical observations challenge integrated information theory's (IIT) reliance on thalamo–cortical interactions as the information integrator. More likely, the cortex streams processed information to a still-enigmatic consciousness generator, one perhaps located in the brainstem.

Merker, Williford, and Rudrauf make several arguments against the integrated information theory of consciousness; whereas some have merit, their conclusion that the theory should be discarded is premature. Coming years promise advances in the empirical study of consciousness, and only after theories are independently tested with shared data can they be ruled in or out. We propose future research directions.

Advances in behavioral and brain sciences have engendered wide ranging efforts to help understand consciousness. The target article suggests that abstract computational models (such as integrated information theory [IIT]) are ill-advised. This commentary broadens the discussion to include mysteries of subjective experience that are inconsistent with current neuroscience. It also discusses progress being made through demystifying specific cases and pursuing evolutionary considerations.

I concur with Merker and colleague's critiques, suggesting that hypotheses about the evolutionary function of consciousness can help address them. Brains are parallel systems that function to compute possible actions and predict outcomes. I hypothesize that a core function of consciousness per se is the global feedback of information about those actions actually executed, supporting local learning via neuronal updating.

A logical explanation of consciousness has been known for decades. The brain must construct a specific set of information about conscious feeling (theory-of-mind information), causing people to believe, think, and claim to have consciousness. Theories that propose an actual, intangible feeling are non-explanatory. They add a magical red herring while leaving unexplained the objective phenomena: the believing, thinking, and claiming.

The integrated information theory (IIT) equates levels of consciousness with the amount of information integrated over the elements that constitute a system. Conscious visual perception provides two observations that contradict the IIT. First, objects are accurately perceived when presented for ≪100 ms during which time no neural integration is possible. Second, an object is seen as an integrated whole and, concurrently, all constituent elements are evident. Because integration destroys information about details, IIT cannot account for perceptual detail preservation.

The target article's critique of the integrated information theory (IIT) of consciousness is misguided on several fronts, which I hope are addressed in other comments, but here I focus on the connection (or supposed lack thereof) between IIT and rigorous phenomenology, and IIT's connection to the psychophysics of perception.

Any neurobiological model claiming explanation of a complex human phenomenon should start with an explicit definition of the explanandum. If a classical intensional definition is impossible, we can use a descriptive definition by listing necessary criteria (e.g., of consciousness). This commentary suggests four meta-criteria that different proposed criteria of consciousness should fulfill: phenomenological consensus, empirical evidence, domain specificity, and non-circularity.

Interpreting empirical measures of integration and differentiation as indices of cortical performance and memory consolidation during wakefulness rather than consciousness per se is inconsistent with the literature. Recent studies show that these theory-inspired measures can dissociate from such processes and reliably index the brain's capacity for experience. We consider this as a positive trend in consciousness research.

The groundbreaking, viewpoint theory of Merker et al. explains several properties of the conscious field, including why the observer cannot directly apprehend itself. We propose that viewpoint theory might also provide a progressive, constitutive marker of consciousness and shed light on why most of the contents of consciousness are encapsulated.

Merker et al. argue that integrated information theory (IIT) is not a theory of consciousness because the IIT formalism does not match phenomenology. I argue that the authors ultimately fail to articulate the problem of the inference of the postulates from the axioms. I suggest a different version of this problem, and argue that this can help rethink IIT's potential for consciousness science.

Merker et al.'s critique calls for a deeper analysis of panpsychism. In principle, the concept of integrated information can be applied to photodiodes and subatomic particles, but I suggest the main obstacle is the lack of any evidence to confirm the presence of consciousness. Also MRW's perspectivalist theory illustrates the difficulties in synthesizing a full-fledged theory of consciousness.

This commentary suggests that the physical substrate of integrated information is dependent on the reference frame used to observe it. Furthermore, it uses a thought experiment – can a neuroscientist, locked in a closed room and connected through Zoom with his grandmother to demonstrate that the consciousness of his grannie is NOT in the PC? – to underline the problems that neglecting reference frames may cause to consciousness research.

We propose that any theory of visual awareness must explain the gradient of different awareness measures over experimental conditions, especially when those measures form double dissociations among each other. Theories meeting this requirement must be specific to the measured facets of awareness, such as motion, contrast, or color. Integrated information theory (IIT) lacks such specificity because it is an underconstrained theory with unspecific predictions.

The target article misrepresents the foundations of integrated information theory (IIT) and ignores many essential publications. It, thus, falls to this lead commentary to outline the axioms and postulates of IIT and correct major misconceptions. The commentary also explains why IIT starts from phenomenology and why it predicts that only select physical substrates can support consciousness. Finally, it highlights that IIT's account of experience – a cause–effect structure quantified by integrated information – has nothing to do with “information transfer.”