Four Attitudes Towards Singularities in the Search for a Theory of Quantum Gravity

TL;DR

This paper examines how different attitudes towards singularities influence the development of quantum gravity theories, classifying four perspectives and their implications for theory resolution and completeness.

Contribution

It introduces a classification of four attitudes towards singularities in quantum gravity research, illustrating how these perspectives lead to different theoretical scenarios.

Findings

Two attitudes promote singularity resolution

One attitude emphasizes the necessity of a quantum gravity theory

Different attitudes shape the expectations and development paths of QG theories

Abstract

Singularities in general relativity and quantum field theory are often taken not only to motivate the search for a more-fundamental theory (quantum gravity, QG), but also to characterise this new theory and shape expectations of what it is to achieve. Here, we first evaluate how particular types of singularities may suggest an incompleteness of current theories. We then classify four different `attitudes' towards singularities in the search for QG, and show, through examples in the physics literature, that these lead to different scenarios for the new theory. Two of the attitudes prompt singularity resolution, but only one suggests the need for a theory of QG. Rather than evaluate the different attitudes, we close with some suggestions of factors that influence the choice between them.