Measurand: a cornerstone concept in metrology

This paper proposes to discuss some concepts whose importance is fundamental to any theory of measurement. From the epistemological point of view there is a very significant inconsistency in the concept of measurand contained in the GUM. According to the model adopted by the GUM, a particular measurand remains the same measurand after a change in its definition, notwithstanding the fact that new conditions had been included or other pre-existing conditions had been altered in the definition. And also notwithstanding the very probable fact that, in consequence, the uncertainty component associated with its definition had been changed. The problem that arises from this theoretical model is that a particular measurand is not completely characterized by a precise and unique definition. Instead, it is considered an 'ideal' utopian particular concept to which would converge a specific series of 'measurands' (more properly their definitions), continually redefined in an infinite succession. Such a theoretical basis seems very inappropriate: the model intends to determine the uncertainty of uncertainly defined particular measurands. Of great relevance is the proposal of a new definition for the concept of measurand, a concept that interfaces the realms of Metrology and experimentation. Other concepts have been created or redefined with sufficient precision and selectivity to consider some aspects that remain somewhat confused in the model of measurement currently applied. [PUBLICATION ABSTRACT]