Talk: James Owen Weatherall (UCI)

Title:

Two Tooth Fairies and a Dentist: Closing the Loop on Lambda CDM

Abstract:

The Standard (Lambda CDM) Model of Cosmology has three components that many commentators in physics and philosophy of science have highlighted as surprising and epistemically problematic: dark matter, dark energy, and inflation. In this talk, I will discuss each of these through the lens of the logic of evidence in gravitational theory described in George Smith's classic article "Closing the Loop". I will argue that from this perspective, dark matter has an importantly different status from dark energy and inflation. This is because dark matter is causally efficacious in a far broader range of physical systems and at very different scales, yielding a rich form of evidence supporting its existence and some of its properties. Dark energy and inflation, meanwhile, are not only more weakly supported by current evidence, it is unclear if strong evidence could be found for them, even in principle.