One-dimensional physical quantities

Attempts to formulate a well-based operational definition of physical entities were first proposed in the end of the 19-th century by Hermann von Helmholtz and Otto Hölder. The problem consists in finding how to associate a number (the value of the entity) with a non-numerical entity (the entity itself).

The paper presents a modern reading of the above mentioned authors. Paraphrasing Feynman in his classic work on path integrals, “there is a pleasure in recognizing old things from a new point of view”.