Primitivism and Reductionism about the Arrow of Time in Physics

CRISTIAN LÓPEZ

Buenos Aires

Workshop; Workshop on Reductionism in Physics; 2023

SADAF

hough the directionality of time seems pervasive and evident, its physical foundations have been disputed for decades. From the probabilistic nature of the directionality of time to its relation to decays in weak interactions, the beaten track has greatly been reductionist: the directionality of time ultimately boils down to a de facto and/or de iure physical asymmetry, such as the increase of entropy in isolated system, the expansion of the universe, electromagnetic radiation, non-time-reversal invariance dynamics, gravitational dynamics, among many others. It seems to suggest that the arrow of time is real only in a derivative sense. In this paper I assess some of the philosophical assumptions that underlie a reductionist approach to the study of the arrow of time in physics. I also show why these assumptions may be conceptually problematic and unsatisfactory. Finally, I pave the way for an alternative approach, which takes the directionality of time as primitive rather than derivative.