Observational Indistinguishability and the Beginning of the Universe

TL;DR

This paper argues that observational data cannot definitively determine whether the universe had a beginning, due to limitations in classical spacetime models and the indistinguishability of certain cosmological scenarios.

Contribution

It introduces new theoretical results showing the observational indistinguishability of universe beginning scenarios and extends classical theorems to support this.

Findings

Observers cannot gather enough data to confirm a cosmic beginning in most classical spacetimes.

Past singular dust FLRW models have indistinguishable counterparts without a beginning.

Confirmation theory errors undermine common strategies for asserting a universe beginning.

Abstract

Can we infer whether all of physical reality began to exist? Several novel results are offered suggesting a negative verdict. First, a common strategy for defending a cosmic beginning involves showing that individual beginningless cosmological models are implausible. This strategy is shown to make an elementary error in confirmation theory. Second, two necessary (but not necessarily sufficient) conditions are offered for a cosmic beginning. Third, three extensions are offered to the Malament-Manchak theorems. The three extensions show that in almost all classical spacetimes, observers cannot collect sufficient data to determine whether the application conditions for the classic singularity theorems are satisfied or whether their spacetime satisfies the two necessary conditions for a cosmic beginning. Lastly, a reply is offered to the objection that the skeptical consequences of the three extensions can be overcome with induction. Importantly, all past singular dust FLRW spacetimes have observationally indistinguishable counterparts which, while sharing a number of important local properties, either do not include a singularity to the past of every point or else do not have the sort of time ordering intuitively required for a cosmic beginning.