Can entropy be defined for and the Second Law applied to the entire universe?

TL;DR

This paper argues that entropy and the Second Law cannot be applied to the entire universe, challenging common assumptions and tracing the origins of this misconception back to Clausius.

Contribution

It clarifies the conceptual limitations of applying entropy and the Second Law to the universe and critiques recent justifications for such applications.

Findings

Entropy and the Second Law are not applicable to the universe.

Historical analysis traces misconceptions back to Clausius.

Recent justifications for universe-scale entropy are flawed.

Abstract

This article provides answers to the two questions posed in the title. It is argued that, contrary to many statements made in the literature, neither entropy, nor the Second Law may be used for the entire universe. The origin of this misuse of entropy and the second law may be traced back to Clausius himself. More resent (erroneous) justification is also discussed.