Observational Selection Effects in Quantum Cosmology

TL;DR

This paper discusses how observational selection effects impact quantum cosmology theories, proposing principles for Bayesian meta-theories and exploring the Sensible Quantum Mechanics framework to test different cosmological models.

Contribution

It introduces principles for Bayesian meta-theories and analyzes the Sensible Quantum Mechanics framework in the context of quantum cosmology.

Findings

SQM allows testing between single-history and many-worlds theories

Fake universes and Boltzmann brains pose potential threats to theories

Past evolutionary steps may be uniquely rare in the observable universe

Abstract

Scientific theories need to be testable by observations, say using Bayes' theorem. A complete theory needs at least the three parts of dynamical laws for specified physical variables, the correct solution of the dynamical laws (boundary conditions), and the connection with observations or experience or conscious perceptions (laws of psycho-physical parallelism). Principles are proposed for Bayesian meta-theories. One framework that obeys these principles is Sensible Quantum Mechanics (SQM), which is discussed. In principle, it allows one to test between single-history and many-worlds theories, and to discuss threats to certain theories from fake universes and Boltzmann brains. The threat of fake universes may be dismissed if one doubts the substrate-independence of consciousness, which seems very implausible in the SQM framework. Boltzmann brains seem more problematic, though there are many conceivable solutions. SQM also suggests the possibility that past steps along our evolutionary ancestry may be so rare that they have occurred nowhere else within the part of the universe that we can observe.