Underdetermination in dark energy and inflationary cosmology

Thesis

This thesis investigates a number of topics in cosmology.

Part II presents physics results that provide a novel perspective concerning the underdetermination issues facing model building within both inflation and dark energy research. Here, I focus on a number of scalar field models, and illustrate the extent to which they can saturate the parameter spaces that describe both early and late-time cosmological observables in an essentially arbitrary manner, as well as approximate the predictions of other distinct models with arbitrarily close precision.

Parts III and IV examine a number of philosophical issues relevant to this state of affairs. Among other topics, I explore whether deploying particular non-empirical arguments or explanatory considerations might allow for promising discrimination strategies when faced with competing cosmological theories. Finally, I consider the possibility that the present situations regarding inflation and dark energy might reflect novel cases of the permanent underdetermination of theory by evidence and explore the epistemic strategies that may be available to us. I argue that resorting to effective field theories is promising under certain conditions and can be seen as analogous to the overarching and common core strategies that have previously been deployed in cases of strong underdetermination.

Authors: Wolf, WJ

• DOI: 10.5287/ora-o09n2jqa4
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: cosmic inflation; dark energy; cosmology; underdetermination
• Subjects: Philosophy of Science; Physics; Philosophy; Cosmology; Astrophysics