The Arrow of Time as an Asymmetry of Record Formation

The arrow of time is one of the most profound and persistent mysteries in physics. While the microscopic dynamical laws are (almost) time-symmetric, the macroscopic world exhibits a clear temporal direction. This paper introduces a records-based diagnostic criterion for evaluating explanations of temporal asymmetry: any successful account must explain why stable, redundant records of a system's state are generically produced toward the future, but not the past. We show how the established frameworks of decoherence and quantum Darwinism provide the mechanism for record creation, but that the temporal asymmetry of this process is not derivable from dynamics alone. Instead, it depends crucially on a low-entropy boundary condition—the Past Hypothesis. We then critically evaluate leading alternative explanations—including inflationary cosmology, quantum cosmology, and fluctuation scenarios—demonstrating that they either fail to meet our diagnostic criterion or covertly presuppose the asymmetry they seek to explain. We argue that the records criterion does not replace the Past Hypothesis but constrains what any replacement would have to accomplish. By distinguishing record formation as a dynamical process from record availability as an epistemic structure, we clarify that the arrow of time is best understood not as a feature of dynamics, but as a structural consequence of boundary conditions that permit asymmetric epistemic access for embedded observers. The problem of time's arrow is thus most precisely formulated as: why did our universe begin in a state that permits the temporally asymmetric proliferation of records?