Present records of the Past Hypothesis

Abstract

A striking feature of our world is that we only seem to have records of the past. To explain this ‘record asymmetry’, Albert and Loewer claim that the Past Hypothesis induces a narrow probability density over the world’s possible past macrohistories, but not its future macrohistories. Because we’re indirectly acquainted with this low-entropy initial macrostate, our observations of records allow us to exploit the associated narrow density to infer the past. I will argue that Albert and Loewer cannot make sense of why this probabilistic structure exists without falling back on the very records they wish to explain. To avoid this circularity, I offer an alternative account: the ‘fork asymmetry’ explains the record asymmetry, and this in turn explains the narrow density—not vice versa.