# On the statistical arrow of time

## TL;DR

This paper critically examines the common belief that the arrow of time originates from entropy increase, arguing that the subjective interpretation of probability conflicts with the idea of time's arrow as a fundamental property of nature.

## Contribution

It challenges the subjective interpretation of entropy in the foundations of statistical mechanics and argues for the arrow of time as a fundamental physical property.

## Key findings

- Subjective interpretation of entropy conflicts with the fundamental nature of time's arrow.
- Abandoning the second law's role undermines the philosophical basis of the arrow of time.
- The paper advocates for viewing the arrow of time as an intrinsic feature of physical reality.

## Abstract

What is the physical origin of the arrow of time? It is a commonly held belief in the physics community that it relates to the increase of entropy as it appears in the statistical interpretation of the second law of thermodynamics. At the same time, the subjective information-theoretical interpretation of probability, and hence entropy, is a standard viewpoint in the foundations of statistical mechanics. In this article, it is argued that the subjective interpretation is incompatible with the philosophical point of view that the arrow of time is a fundamental property of Nature. The subjectivist can only uphold this philosophy if the role played by the second law of thermodynamics in defining time's arrow is abandoned.