City Research Online

Abstract

To arbitrate theories of consciousness, scientists need to understand mathematical structures of quality of consciousness, or qualia. The dominant view regards qualia as points in a dimensional space. This view implicitly assumes that qualia can be measured without any effects on it. This contrasts with intuitions and empirical findings to show that by means of internal attention qualia can change when they are measured. What is a proper mathematical structure for entities that are affected by the act of measurement? Here we propose the mathematical structure used in quantum theory, in which we consider qualia as “observables” (i.e., entities that can, in principle, be observed), sensory inputs and internal attention as “states” that specify the context that a measurement takes place, and “measurement outcomes” with probabilities that qualia observables take particular values. Based on this mathematical structure, the Quantum-like Qualia (QQ) hypothesis proposes that qualia observables interact with the world, as if through an interface of sensory inputs and internal attention. We argue that this qualia-interface-world scheme has the same mathematical structure as observables-states-environment in quantum theory. Moreover, within this structure, the concept of an “measurement instrument” in quantum theory can precisely model how measurements affect qualia observables and states. We argue that QQ naturally explains known properties of qualia and predicts that qualia are sometimes indeterminate. Such predictions can be empirically determined by the presence of order effects or violations of Bell inequalities. Confirmation of such predictions substantiates our overarching claim that the mathematical structure of QQ will offer novel insights into the nature of consciousness.

Publication Type:	Article
Additional Information:	Copyright © 2025 Tsuchiya, Bruza, Yamada, Saigo and Pothos. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Publisher Keywords:	qualia, quantum cognition, consciousness, attention, similarity, Bell inequality, bistable perception
Subjects:	B Philosophy. Psychology. Religion > BF Psychology Q Science > QA Mathematics
Departments:	School of Health & Medical Sciences School of Health & Medical Sciences > Psychology
SWORD Depositor:	Symplectic Administrator

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