Abstract

Abstract. Boltzmann brains (BBs) are minds which randomly appear as a result of thermodynamic or quantum fluctuations. In this article, the question of if we are BBs, and the observational consequences if so, is explored. To address this problem, a typology of BBs is created, and the evidence is compared with the Simulation Argument. Based on this comparison, we conclude that while the existence of a “normal” BB is either unlikely or irrelevant, BBs with some ordering may have observable consequences. There are two types of such ordered BBs: Boltzmannian typewriters (including Boltzmannian simulations), and chains of observer moments. Notably, the existence or non-existence of BBs may have practical applications for measuring the size of the universe, achieving immortality, or even manipulating the observed probability of events. Disclaimer and trigger warning: some people have emotional breakdowns when thinking about topics described in the article, especially the “flux universe”. However, everything eventually adds up to normality.