Does Quantum Gravity Happen at the Planck Scale?

Philosophy of Physics, vol. 3

Abstract

The claim that, at the so-called Planck scale, our current physics breaks down and a new theory of quantum gravity is required is ubiquitous, but the evidence is shakier than the confidence of those assertions warrants. In this paper, I survey five arguments in favor of this claim—based on dimensional analysis, quantum black holes, generalized uncertainty principles, the nonrenormalizability of quantum gravity, and theories beyond the standard model—but find that none of them succeed. The argument from nonrenormalizability is the most convincing, yet it requires the unwarranted assumption that the same constant of action occurs in every quantum field theory. Therefore, our theories don’t (yet) predict that quantum gravity happens at the Planck scale.

Authors 1

1. Caspar Jacobs corresponding Aachen

   Leiden University

   Affiliation as printed

   Leiden University