Abstract

The chapter begins by explaining the concepts of quantity and magnitude. It then presents the method of measurement without using magnitude. This method of direct measurement can be achieved through the observation of the transitive relation among objects. A particular set of equivalence classes is selected to serve as a unit of measurement and is assigned magnitude. The concept of measurement error and approximation is then introduced. In some cases, such as temperature, indirect measurement, or measurement in terms of a different quantity, yields less error and proves more accurate and convenient than direct measurement. In general, indirect measurements of different kinds are appropriate at different regions of the scale.