Philosophical questions about the arrow of time

Abstract Philosophical questioning about the arrow of time is an active research area, but one with a long and industrious history in both physics and philosophy. This paper begins by distinguishing between a puzzle about the origin of the thermodynamic time asymmetry and questions about whether the thermodynamic time asymmetry can itself explain other temporal asymmetries. It goes on to give a brief description of how the puzzle arises in classical mechanics, followed by an interlude on whether and how quantum mechanics might change the situation. Finally, it takes a closer look at the puzzle in terms of statistical mechanics and one proposed solution.