The physical basis of natural units and truly fundamental constants

TL;DR

This paper argues that natural units are not just convenient but have a physical basis, linking fundamental constants and units to inherent properties of nature.

Contribution

It provides a physical justification for natural units and classifies fundamental constants as units-dependent or units-independent.

Findings

Natural units have a physical basis beyond convenience.

Fundamental constants can be classified as units-dependent or units-independent.

Inherent constants of nature are identified among fundamental constants.

Abstract

The natural unit system, in which the value of fundamental constants such as c and h are set equal to one and all quantities are expressed in terms of a single unit, is usually introduced as a calculational convenience. However, we demonstrate that this system of natural units has a physical justification as well. We discuss and review the natural units, including definitions for each of the seven base units in the International System of Units (SI) in terms of a single unit. We also review the fundamental constants, which can be classified as units-dependent or units-independent. Units-independent constants, whose values are not determined by human conventions of units, may be interpreted as inherent constants of nature.