What is Measured?

Abstract

AbstractThis chapter aims to explore some key components of an ontology and an epistemology of properties. What is evaluated, and more specifically, measured, are properties of objects, such as lengths of rigid bodies and reading comprehension abilities of individuals, and the results of evaluations, and thus of measurements, are values of properties. Hence, a study of the nature of properties and of our ways of securing knowledge of them is a pivotal component of measurement science. We start from the hypothesis that properties of objects are associated with modes of empirical interaction of the objects with their environment. Consistently with the model-dependent realism introduced in Chap. 4, the Basic Evaluation Equation$${\text{property}}\,{\text{of}}\,{\text{a}}\,{\text{given}}\,{\text{object}} = {\text{value}}\,{\text{of}}\,{\text{a}}\,{\text{property}}$$of which the relation$${\text{measurand}} = {\text{measured}}\,{\text{value}}\,{\text{of}}\,{\text{a}}\,{\text{property}}$$is a specific case, is interpreted as a claim of an actual referential equality, which conveys information on the measurand because the measurand and the measured value remain conceptually distinct entities.