Why Do We Want a Theory of Quantum Gravity?

TL;DR

This paper discusses the motivations behind the pursuit of a quantum gravity theory, highlighting philosophical and theoretical reasons rather than empirical anomalies, and encourages critical evaluation of these motivations.

Contribution

It provides a critical perspective on the philosophical and theoretical motivations for developing a quantum gravity theory, questioning their role in guiding research.

Findings

Motivations include unification and resolving incompatibilities.

Black hole thermodynamics influences quantum gravity ideas.

Theoretical and philosophical concerns drive the search, not empirical anomalies.

Abstract

The search for a new scientific theory is typically prompted by an encounter with something in the world that cannot be explained by current theories. This is not the case for the search for a theory of quantum gravity, which has been primarily motivated by theoretical and philosophical concerns. This Element introduces some of the motivations for seeking a theory of quantum gravity, with the aim of instigating a more critical perspective on how they are used in defining and constraining the theory sought. These motivations include unification, incompatibilities between general relativity and quantum field theory, consistency, singularity resolution, and results from black hole thermodynamics.