Philosophy of Physics Seminar (Thursday - Week 1, TT25)

Abstract: Despite the incredibly empirical successes that modern cosmology has seen in establishing the Λ-Cold Dark Matter model, I argue that modern cosmology faces a further profound challenge: the permanent underdetermination of the microphysical nature of its exotic energy components: inflation, dark matter, and dark energy. Drawing historical parallels with the role of spectroscopy in revealing the microphysical nature of atomic physics, I argue that the epistemic barriers obstructing us from ascertaining the microphysical nature of these exotic energy components are significant. Confronted with this prospect of permanent underdetermination, I apply (a) a taxonomy of possible responses to underdetermination and (b) an understanding of both dark energy and inflationary cosmology from an effective field point of view to the cases of inflation and dark energy. I argue that, under certain conditions, there are available viable responses which can alleviate at least some of the concerns about underdetermination in the dark energy and inflationary sectors. However, outside of these specific scenarios, the epistemic threat of permanent underdetermination will persist.