From Fluids to Black Holes: Analogical Reasoning in Physics

Scientists often transfer ideas and concepts from one field to another. The concept of fluid, for example, is also used successfully outside of hydrodynamics.

This strategy helps scientists to find new theories and understand new phenomena. In addition to this heuristic function of analogies, analogies (and analogical reasoning more broadly) are sometimes thought to have an epistemic function. The aim of this talk is to explain this epistemic function in more detail and to examine under what conditions, if any, analogies have this function. In particular, we will ask whether reference to an analogy to a well-understood theory or phenomenon can be used to confirm a new theory. This discussion has recently been fueled by the claim that the thesis that black holes emit Hawking radiation can be confirmed by observing the analogous Hawking radiation from black holes in a Bose-Einstein condensate. We are dealing here with a situation in which an experimentally inaccessible system (the black hole) is simulated by a somewhat analogous system (a Bose-Einstein condensate), with the phenomenon in question (Hawking radiation) being caused by an experimental intervention in the analogous system. Can we really learn anything about black holes from Bose-Einstein condensates?