Falsifying anthropics

Abstract

We propose using fuzzy axion dark matter to test the anthropic principle. A very light axion can be directly detectable, at least by black hole superradiance effects. The idea then is that gravitational and astrophysical observations can discover a light axion in the regime where it must be all of dark matter with abundance which must be set up by the anthropic principle, due to excessive primordial misalignment induced by inflation-induced Brownian drift of fluctuations. Yet it may turn out that dark matter is something else instead of this axion. Since the de Sitter-induced axion misalignment controlled only by the de Sitter curvature cannot be evaded, this would invalidate the anthropic prediction of the dark matter abundance.