Integrated information theory and axioms of experience

Friston, Wiese and Hobson (2020) describe IIT as an axiomatic approach. It begins with assumptions about what information processing must look like if it is to explain conscious experience.² They name five axioms: intrinsic existence, composition, information, integration and exclusion.³ The axioms are claimed as essential properties of experience itself.

Friston and colleagues (2020) compare IIT with the free energy principle (FEP). They say IIT deals with probability distributions over the states of a system, whereas the FEP is stated in terms of beliefs about something external.⁵ They also state that, at the time of writing, a gap separates the two approaches. Even so, they argue that one can establish some construct validity between the FEP and IIT through the axioms on which IIT rests.⁴ Their argument is heuristic. They do not claim the two theories are equivalent.

McFadden (2020) argues for a theory of consciousness based on the electromagnetic field of the brain. He holds that EM fields are always unified, so the brain has only one such field.⁶ He describes the qualia of hearing middle C as what a matching field perturbation feels like from the inside.⁷ McFadden notes that IIT has also made proposals about qualia. Fields, Glazebrook and Levin (2021) report a prediction they judge in line with IIT's expectations and say it gives those expectations a physical basis.⁸

Levin (2019) objects to the single self that he reads into IIT (Tononi, 2008). He argues that most biological systems contain multiple, nested selves.¹ Bongard and Levin (2023) quote Hoel on exclusion. Many scales of description carry some integrated information, so Hoel says the exclusion postulate is needed to get one definite consciousness. He adds that it is the most controversial postulate within IIT.⁹