Naotsugu Tsuchiya
Monash University, Turner Institute for Brain and Mental Health
Integrated information Consciousness is intrinsic causal power, measured as integrated information
Naotsugu Tsuchiya runs a consciousness science laboratory at Monash University that sits between empirical neuroscience and formal theory. His research programme tests predictions of Integrated Information Theory and adjacent structural approaches against EEG and fMRI data while also pursuing a more abstract question, how far a mathematical description of one system’s experience can be used to say anything about another’s.
That question is the subject of “The Rosetta Stone and Levels of Principled Inference to the Experience of Another Mind,” a 2026 paper with Kallum Robinson, Giulio Tononi, and Matteo Grasso. The paper compares two structural approaches, the Qualia Structure Paradigm, which describes an experience by its relations to every other possible experience, and Integrated Information Theory, which describes an experience by the internal causal structure that specifies it. Using category theory, the authors formalize discrete levels of correspondence between two systems’ experiential structures, from full isomorphism down through strong and weak adjunction to a principled limit past which no further inference is possible. Neither framework closes what the paper calls the acquaintance gap, direct access to what it is like to be the other system, but both let researchers state exactly how much structural correspondence has or has not been established.
The result bears directly on any claim that an AI system’s internal representations resemble human experience. Tsuchiya’s collaboration treats resemblance claims as gradable and falsifiable rather than binary, meaning a claim like “this model represents color similarity structurally like humans do” can be assigned a specific inferential grade, isomorphism, adjunction, or nothing provable at all, instead of being accepted or dismissed wholesale.
Known for. Formal and mathematical approaches to the structure of conscious experience
Coverage on this site
Related researchers
- Kallum RobinsonUniversity of Wisconsin-Madison, Center for Sleep and ConsciousnessFormal comparison of structural theories of consciousness using category theory
- Larissa AlbantakisUniversity of Wisconsin-Madison, Center for Sleep and ConsciousnessIntegrated Information Theory 4.0 and dissociating intelligence from consciousness in artificial systems
- Costas AnastassiouAllen InstituteEphaptic coupling of cortical neurons, endogenous electric fields as causal participants in neural activity, extracellular field biophysics
- Anton ArkhipovAllen Institute for Brain ScienceLarge-scale neural simulation, biophysically detailed cortical models, AIBRAIN program, State of Brain Emulation Report 2025
- Bernard J. BaarsThe Neurosciences InstituteGlobal Workspace Theory (GWT), cognitive architecture of conscious access, A Cognitive Theory of Consciousness (1988), In the Theater of Consciousness (1997)
- Adam B. BarrettSussex Centre for Consciousness Science, University of SussexContinuous field formulations of Integrated Information Theory, Measure-theoretic Phi, practical complexity measures, Granger causality
Naotsugu Tsuchiya is listed with the other integrated information theorists, who hold that consciousness is intrinsic causal power, measured as integrated information. The theory family behind that position is set out in the index of consciousness theories. Every researcher covered on this site is indexed in the directory of consciousness researchers.