Between definition and explanation. Epistemic evaluation of the problem of the arrow of time

Abstract

The aim of this article is to problematize the notion of the arrow of time by distinguishing between theories that allow for the definition of a temporal orientation and those that could explain its origin. It argues that a non-circular explanation of directionality is required, one that differs from operational criteria based on asymmetric processes. An analysis is undertaken to reconstruct the strategy we have termed from processes, through which the problem of the arrow of time has been approached. It is shown that the second law of thermodynamics allows us to order processes in such a way that we can define a before and after. However, effective irreversibility depends on asymmetric or boundary assumptions that introduce orientation. The article concludes that, under the proposed epistemic standard (non-circularity and independence from processes), there is still no genuine theory of the arrow of time, since current accounts offer operational definitions and statistical or cosmological rationalizations, but not a foundational explanation of its origin.