Cosmological Ontology and Epistemology

TL;DR

This paper explores the philosophical foundations of cosmology, proposing a Bayesian framework to evaluate theories based on their measure of observations, and discusses key issues like the measure problem, Born's rule, and the existence of God.

Contribution

It introduces a Bayesian approach to cosmological theory evaluation that incorporates ontological and epistemological assumptions, addressing foundational problems in the field.

Findings

Proposes a normalized measure-based likelihood for testing cosmological theories

Discusses the measure problem and its implications for cosmological predictions

Explores philosophical issues including the death of Born's rule and the existence of God

Abstract

In cosmology, we would like to explain our observations and predict future observations from theories of the entire universe. Such cosmological theories make ontological assumptions of what entities exist and what their properties and relationships are. One must also make epistemological assumptions or metatheories of how one can test cosmological theories. Here I shall propose a Bayesian analysis in which the likelihood of a complete theory is given by the normalized measure it assigns to the observation used to test the theory. In this context, a discussion is given of the trade-off between prior probabilities and likelihoods, of the measure problem of cosmology, of the death of Born's rule, of the Boltzmann brain problem, of whether there is a better principle for prior probabilities than mathematical simplicity, and of an Optimal Argument for the Existence of God.