Anthropic Reasoning and Quantum Cosmology

TL;DR

This paper examines how anthropic reasoning can be applied to quantum cosmology, discussing its usefulness, limitations, and uncertainties in predicting the universe's properties based on conditional probabilities.

Contribution

It analyzes the role and challenges of using anthropic reasoning in quantum cosmology, especially under conditions of limited knowledge about the quantum state.

Findings

Anthropic reasoning can inform predictions but has limitations due to uncertainties.

Uncertainty in the quantum vacuum affects anthropic predictions.

Obstacles exist in applying anthropic reasoning to determine the string theory vacuum.

Abstract

Prediction in quantum cosmology requires a specification of the universe's quantum dynamics and its quantum state. We expect only a few general features of the universe to be predicted with probabilities near unity conditioned on the dynamics and quantum state alone. Most useful predictions are of conditional probabilities that assume additional information beyond the dynamics and quantum state. Anthropic reasoning utilizes probabilities conditioned on `us'. This paper discusses the utility, limitations, and theoretical uncertainty involved in using such probabilities. The predictions resulting from various levels of ignorance of the quantum state are discussed including those related to uncertainty in the vacuum of string theory. Some obstacles to using anthropic reasoning to determine this vacuum are described.