Blackwell Reference Online

Extract

Measurement - a central epistemic activity in science - relates a number and a quantity in an effort to estimate the magnitude of that quantity. A quantity is typically a property of a physical configuration, such as length or weight, and determines a function that applies to a domain or class of objects. At this high level of abstraction, the description of the purpose and relation of measurement is metaphysically neutral, leaving open the question of whether the domain is observable (empirical) or unobservable (nonempirical). We can determine and express the value of a quantity as long as we can describe the quantitative relationships that obtain between two or more objects. The familiar mathematical relationships of “greater than,” “less than,” and “equal to” are the ones most commonly used to express quantitative relations: these relations provide a basis for the articulation of other quantitative relationships such as “farther than,” “shorter than,” or “same heaviness as.” It is instruments that most commonly allow us to discover and formulate the relationships expressed. Measurement practice has a long history, primarily occupied with astronomical inquiry and engineering concerns of volume, density, and speed, and associated with the most notable figures in the history of science. Historically, measurements were made with laboratory instruments and with telescopic and navigational ... log in or subscribe to read full text