F1000Research
June 25, 2026
Kyoko Kusano, Hayato Saigo, Naotsugu Tsuchiya
Abstract* Characterizing qualitative aspects of subjective experiences, qualia, remains a challenging open problem. The recent Qualia structure paradigm proposes capturing qualia through massive relations with other qualia. A concrete method for this involves measuring pairwise similarities. This approach has been successfully applied to reveal similarities and differences in qualia structures...
Frontiers in Psychology
2024
Naotsugu Tsuchiya, Peter Bruza, Makiko Yamada et al.
8 citations
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 effect on them. This contrasts with intuitions and empirical findings to show that by means of internal attention qualia can...
Frontiers in Psychology
2023
Shigeru Taguchi, Hayato Saigo
4 citations
Human consciousness is characterized by constant transitions in time. On the other hand, what is consciously experienced always possesses the temporal feature of "now." In consciousness, "now" constantly holds different contents, yet it remains "now" no matter how far it goes. This duality is thematized in Husserlian phenomenology as "the standing-streaming now." Although this phrase appears...
Consciousness and Cognition
May 1, 2022
Naotsugu Tsuchiya, Steven Phillips, Hayato Saigo
Qualitative relationships between two instances of conscious experiences can be quantified through the perceived similarity. Previously, we proposed that by defining similarity relationships as arrows and conscious experiences as objects, we can define a category of qualia in the context of category theory. However, the example qualia categories we proposed were highly idealized and limited to...
Frontiers in Psychology
2022
Naotsugu Tsuchiya, Hayato Saigo, Steven Phillips
What are the nature of the relationship among qualia, contents of consciousness, and behavioral reports? Traditionally, this type of question has been only addressed via a qualitative and philosophical approach. Some theorists emphasize an incomplete and inaccurate nature of reports of one's own qualia to discourage formal research programs on qualia. Other empirical researchers, however, have...
Neuroscience of Consciousness
October 1, 2021
Naotsugu Tsuchiya, Hayato Saigo
Abstract Characterizing consciousness in and of itself is notoriously difficult. Here, we propose an alternative approach to characterize, and eventually define, consciousness through exhaustive descriptions of consciousness’ relationships to all other consciousness. This approach is founded in category theory. Indeed, category theory can prove that two objects A and B in a category can be...
Entropy
December 1, 2019
Georg Northoff, Naotsugu Tsuchiya, Hayato Saigo
Consciousness is a central issue in neuroscience, however, we still lack a formal framework that can address the nature of the relationship between consciousness and its physical substrates. In this review, we provide a novel mathematical framework of category theory (CT), in which we can define and study the sameness between different domains of phenomena such as consciousness and its neural...
Neurosciences research
June 1, 2016
Naotsugu Tsuchiya, Shigeru Taguchi, Hayato Saigo
One of the most mysterious phenomena in science is the nature of conscious experience. Due to its subjective nature, a reductionist approach is having a hard time in addressing some fundamental questions about consciousness. These questions are squarely and quantitatively tackled by a recently developed theoretical framework, called integrated information theory (IIT) of consciousness. In...
Naotsugu Tsuchiya, Masafumi Oizumi, Makiko Yamada et al.
preprint
我々が主観的に感じる意識と、脳の中で生じている物理・化学現象の間をつなぐ科学法則とは一体どのようなものだろうか？...