Abstract

It is generally accepted that science sometimes involves reasoning with analogies. Often, this simply means that analogies between disparate objects of study might be used as heuristics to guide theory development. Contemporary black hole physics, however, deploys analogical reasoning in a way that seems to overreach this traditional heuristic role. In this chapter, I describe two distinct pieces of analogical reasoning that are quite central to the contemporary study of black holes. The first underpins arguments for the existence of astrophysical Hawking radiation, and the second underpins arguments for black holes being ‘genuinely’ thermodynamical in nature. I argue that while these are distinct analogical arguments, they depend on one another in an interesting way: the success of the second analogical argument presupposes the success of the first. This induces a tension for those who wish to take black hole thermodynamics seriously, but who are sceptical of the evidence provided for astrophysical Hawking radiation by the results of analogue gravity. I consider three ways to resolve this tension, and show that each fails.