The Fundamental Tension in Integrated Information Theory 4.0’s Realist Idealism

Integrated Information Theory (IIT) 4.0 proposes that consciousness is the fundamental reality, not something generated by the brain, and that the physical world is merely a tool for describing it. This idealistic ontology, however, is underdeveloped and creates a tension with the theory's simultaneous claim that an external world exists independently of our minds. The authors clarify this ontology as a combination of phenomenal primitivism, reductionism about Φ-structures, and eliminativism about non-conscious physical entities. They then reject three potential resolutions to the tension and argue that the most plausible solution is a non-solipsistic idealist realism: the external world consists of other conscious experiences beyond one's own.

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Abstract

Integrated Information Theory (IIT) is currently one of the most influential scientific theories of consciousness. Here, we focus specifically on a metaphysical aspect of the theory’s most recent version (IIT 4.0), what we may call its idealistic ontology, and its tension with a kind of realism about the external world that IIT also endorses. IIT 4.0 openly rejects the mainstream view that consciousness is generated by the brain, positing instead that consciousness is ontologically primary while the physical domain is just “operational”. However, this philosophical position is presently underdeveloped and not rigorously formulated in IIT, potentially leading to many misinterpretations and undermining its overall explanatory power. In the present paper we aim to address this issue. We argue that IIT’s idealistic ontology should be understood as a specific combination of phenomenal primitivism, reductionism regarding Φ-structures and complexes, and eliminativism about non-conscious physical entities. Having clarified this, we then focus on the problematic tension between IIT’s idealistic ontology and its simultaneous endorsement of realism according to which there is some kind of external reality independent of our minds. After refuting three potential solutions to this theoretical tension, we propose the most plausible alternative: understanding IIT’s realism as asserting the existence of other experiences beyond my own, what we call a non-solipsistic idealist realism. We end with concluding remarks and future research avenues.