Navigating permanent underdetermination in dark energy and inflationary cosmology

Understand

We identify troubling cases of so-called `permanent underdetermination' in both dark energy and inflationary cosmology.

• We bring to bear (a) a taxonomy of possible responses to underdetermination, and (b) an understanding of both dark energy and inflationary cosmology from an effective field theory point of view.
• We argue that, under certain conditions, there are viable responses which can arguably alleviate at least some of the concerns about underdetermination in the dark energy and inflationary sectors.
• However, the epistemic threat of permanent underdetermination remains a significant challenge.