Do we know what the temperature is?

TL;DR

This paper critically examines the concept of temperature, highlighting the gap between its theoretical definition in statistical physics and its experimental measurement, and provides an epistemological analysis of phenomenological temperature.

Contribution

It offers a logical and epistemological analysis of the phenomenological temperature, addressing the conceptual gap in current understanding.

Findings

Identifies a gap between theoretical and experimental temperature concepts.

Provides a philosophical analysis of phenomenological temperature.

Highlights the ambiguity in defining temperature in practice.

Abstract

Temperature, the central concept of thermal physics, is one of the most frequently employed physical quantities in common practice. Even though the operative methods of the temperature measurement are described in detail in various practical instructions and textbooks, the rigorous treatment of this concept is almost lacking in the current literature. As a result, the answer to a simple question of "what the temperature is" is by no means trivial and unambiguous. There is especially an appreciable gap between the temperature as introduced in the frame of statistical theory and the only experimentally observable quantity related to this concept, phenomenological temperature. Just the logical and epistemological analysis of the present concept of phenomenological temperature is the kernel of the contribution.