A relational approach to consciousness: categories of level and contents of consciousness

Towards a structural turn in consciousness science

Recent activities in virtually all fields engaged in consciousness studies indicate early signs of a structural turn, where verbal descriptions or simple formalisations of conscious experiences are replaced by structural tools, most notably mathematical spaces. My goal here is to offer three comments that, in my opinion, are essential to avoid misunderstandings in these developments early on. These comments concern metaphysical premises of structural approaches, the viability of structure-preserving mappings, and the question of what a structure of conscious experience is in the first place. I will also explain what, in my opinion, are the great promises of structural methodologies and how they might impact consciousness science at large.

Are Color Experiences the Same across the Visual Field?

It seems obvious to laypeople that neurotypical humans experience color equivalently across their entire visual field. To some neuroscientists, psychologists, and philosophers, though, this claim has been met with skepticism, as neurophysiological evidence indicates the mechanisms that support color perception degrade with eccentricity. However, the argument that this entails altered color experience in peripheral vision is not universally accepted. Here, we address whether color experience is essentially equivalent between central and peripheral vision. To assess this, we will obtain similarity relationships between color experiences across the visual field using both online and laboratory-based far-field displays, while removing the confounds of saccades, memory, and expectation about color experiences. Our experiment was designed to provide clear evidence that would favor either unchanged or altered color experience relationships in the periphery. Our results are consistent with lay people's phenomenological reports: Color experiences, as probed by similarity relationships in central vision and the far field (60°), are equivalent when elicited by large stimuli. These findings challenge the widespread view in philosophy and cognitive science that peripheral color experiences are illusory, and are discussed in the context of their related neurophysiological, psychophysical, and philosophical literature.

An adjunction hypothesis between qualia and reports

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 made substantial progress in understanding the structure of qualia from such limited reports. What is the precise relationship between the two? To answer this question, we introduce the concept of “adjoint” or “adjunction” from the category theory in mathematics. We claim that the adjunction captures some aspects of the nuanced relationships between qualia and reports. The concept of adjunction allows us to clarify the conceptual issues with a precise mathematical formulation. In particular, adjunction establishes coherence between two categories that cannot be considered equivalent, yet has an important relationship. This rises in empirical experimental situations between qualia and reports. More importantly, an idea of adjunction naturally leads to various proposals of new empirical experiments to test the predictions about the nature of their relationship as well as other issues in consciousness research.

What is category theory to cognitive science? Compositional representation and comparison

Category theorists and cognitive scientists study the structural (analogical) relations between domains of interest albeit in different contexts, that is, formal and psychological systems, respectively. Despite this basic commonality, very few cognitive scientists take a category theory approach toward understanding the structure of cognition which raises the question, What is category theory to cognitive science? An answer is given as the slogan "Category theory is to cognitive science as functor is to representation; as natural transformation is to comparison" to make category theory more accessible and informative for cognitive scientists.

Neurophenomenal structuralism. A philosophical agenda for a structuralist neuroscience of consciousness

The program of “neurophenomenal structuralism” is presented as an agenda for a genuine structuralist neuroscience of consciousness that seeks to understand specific phenomenal experiences as strictly relational affairs. The paper covers a broad range of topics. It starts from considerations about neural change detection and relational coding that motivate a solution of the Newman problem of the brain in terms of spatiotemporal relations. Next, phenomenal quality spaces and their Q-structures are discussed. Neurophenomenal structuralism proclaims a homomorphic mapping of the structures of self-organized neural maps in the brain onto Q-structures, and it will be demonstrated how this leads to a new and special version of structural representationalism about phenomenal content. A methodological implication of neurophenomenal structuralism is that it proposes measurement procedures that focus on the relationships between different stimuli (as, for instance, similarity ratings or representational geometry methods). Finally, it will be shown that neurophenomenal structuralism also has strong philosophical implications, as it leads to holism about phenomenal experiences and serves to reject inverted qualia scenarios.