Abstract
This thesis develops functional reduction into a full account of inter-theory reduction in the physical sciences. Functional reduction characterises inter-theory reduction as the recovery of the higher-level behaviour described by the reduced theory in terms of the lower-level reducing theory. For example, finding a statistical mechanical realiser that can play the role of thermodynamic entropy establishes a reductive link between thermodynamics and statistical mechanics, as thermodynamic behaviour can be recovered from statistical mechanics. This account constitutes an original method of reduction offering numerous advantages and has been applied in various domains in the physical sciences. However, for functional reduction to be a full account of theory reduction, we need to specify how theoretical elements and ontology are related within the view, how functional roles are formulated, and how the account is related to other approaches to reduction.We tackle these questions by advancing two alternative frameworks for functional reduction, namely `Syntactic Functional Reduction' and `Semantic Functional Reduction'. They elaborate on functional reduction in different ways. The former expands upon David Lewis' account, employs a logical characterisation of functional roles, and is combined with Nagelian reduction. The latter spells out functional roles mainly in terms of mathematical roles within models and builds on the mathematical approach to reduction. Hence we argue that functional reduction can embed both Nagelian and mathematical reduction and improve on them. We apply these two frameworks to some detailed case studies from physics, to study their implications and improve our understanding of those case studies. Moreover, we apply functional reduction outside of physics, to biochemical entities. Overall, this thesis advances our understanding of functional reduction in science and provides an ideal platform for further applications of the approach.
| Date of Award | 18 Jun 2024 |
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| Original language | English |
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| Supervisor | Karim Thebault (Supervisor) & James A C Ladyman (Supervisor) |