From the Body to the World: Structural Representation and the Mapping Problem
Date
2024
Authors
Nestor, Matthew James
Editors
Advisors
Opie, Jon
O'Brien, Gerard
O'Brien, Gerard
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Thesis
Citation
Statement of Responsibility
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Abstract
It is a guiding hypothesis of the cognitive sciences that the brain pilots the body through the world with the aid of mental representations, neural states that represent, model, or carry information about, our bodies and the external environment. But how do these neural states carry information, or content? Structuralist theories suggest the following answer: neural states represent the environment in virtue of sharing relational structure with the environment. A theory of mental representation should account for the explanatory role that the concept plays in cognitive theory. It should explain, for instance, how neural states cause behaviour in a way that respects the content carried by those neural states. It should also explain how the content carried by neural states can be inaccurate (i.e. misrepresentation). Chiefly, a theory should explain how the content carried by neural states is determinate. Structuralist approaches have difficulty explaining this, because the relation of shared structure, as characterised mathematically by homomorphism, is prolific in the natural world. Everything shares structure with everything else. So, if our mental states represent what they do because they share structure with those things, then there is no determinate answer to the question of what they represent. This is the liberality problem. This dissertation develops a novel theory of structural representation designed to satisfy the explanatory role of mental representation in cognitive theory and, in particular, resolve liberality. I explore three classes of restrictions that can be applied to the formal machinery of homomorphism to curtail liberality: domain-restrictions, relation-restrictions, and mapping-restrictions. I use Cummins’ (1996) application theory as a case-study of a domain-restriction, and Shea’s (2014; 2018) theory of exploitable structural correspondence as a case-study of a relation-restriction. I argue that neither class of restriction, whether taken alone or together, is sufficient to resolve liberality. This is because liberality involves a mapping problem. That is, there is a puzzle as to how neural states map onto environmental states. I go on to explore candidate physical relations that might ground this mapping. I argue against the best-match view, according to which the content-constituting mapping is whichever one best preserves structure. This approach confuses the priority of representational content and accuracy. I also argue against theories according to which the mapping is fixed by the causal transmission of structure from distal to proximal stimuli. Such theories fail to ensure that contents and motor responses are in agreement. They also face the inverse problem. I use the shortcomings of existing theories to develop a novel theory of structural representation, called the structural predication theory of content. The account draws heavily from a branch of engineering called control theory, as well as a theory in computational neuroscience called predictive coding. I argue that the mapping is fixed, in the first instance, by the functional couplings that motor centres have to both the proprioceptive forward-model and the bodily plant. Exteroceptive percepts are then mapped to regions of egocentric space by virtue of sensorimotor integration with the proprioceptive forward-model. In this way, exteroceptive percepts are mapped from the body-model’s map to the body, and from the body to the world.
School/Discipline
School of Humanities : Philosophy
Dissertation Note
Thesis (Ph.D.) -- University of Adelaide, School of Humanities : Philosophy, 2024
Provenance
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