Explanations in Biology

: Perspectives on a Model-based science

Abstract

Biology is a model-based science. Biologists routinely offer explanations by building models of the systems that they wish to study. In this thesis, I explore the different ways in which biologists use models as explanatory tools. To do this, I explore how models explain within three biological domains – molecular biology, systems biology, and systems theory, and situate them within three explanatory frameworks – mechanistic, minimal model, and comparative-functional explanations. I argue that the explanations offered by models within these frameworks are distinct from each other, but that the explanatory imports of one type of model for explanatory frameworks other than the one they are constructed within, is significant. But that to understand how models explain in different frameworks, attention must be paid to their construction which utilises heuristic tools, abstraction, idealizations, and optimising assumptions. I do so by showing how mathematical models of systems biology can be used as heuristics for discovery and in tracking organisational features of mechanisms, but that reducing the role of mathematical models merely to this heuristic role is a mistake. By taking the example of bacterial chemotaxis, I argue that all three types of explanatory models are required to explain the features of the chemotactic network and, by extension, any complex biological system. Lastly, I argue for an explanatory pluralism in biology based on scientific practices as an epistemic tool to deal with the overwhelming complexity of biological systems.

Date of Award	25 Jan 2022
Original language	English
Awarding Institution	University of Bristol
Supervisor	Samir Okasha (Supervisor)