Commensurability

Commensurability (or commensurableness) is an abstract noun, the adjectival form of which is commensurable, and apart from being easier to pronounce, it is easier to define. In defining a concept, the essence or the qualities of the concept are described, that is, saying what makes it what it is and not something else. To say that some things are commensurable is another way of saying that they are capable of being measured by the same standard of values or that they have a common measure.

The meaning of commensurability may be illustrated by showing how the word is used in everyday speech; for example, concepts such as equity and justice and matter and gravity are commensurable because they can be measured by the same set of values. Mind and space are incommensurable because they are not capable of being measured by a common standard. Justice and economic development are incommensurable because there is no common measure to evaluate them.

Commensurability has mathematical connotations, as shown in the following examples. (1) The numbers 12 and 9 are commensurable because they are divisible by 3. (2) A foot and a yard are commensurable because they are capable of being measured by the same unit; that is, they can be translated into inches—namely, 12 inches and 36 inches, respectively. (3) Hours and minutes are also commensurable because they too share a common measure.

With respect to recent research, Thomas Kuhn (1922–1996) and Paul Feyerabend (1924–1994) have both considered commensurability and incommensurability. Feyerabend (whose career included service in the German Wehrmacht as an officer and then being wounded on the Russian front) argued that the semantic principles of construction underpinning a theory could be replaced by another theory. As a result, theories could not always be compared with their context. Kuhn claimed that science developed in one particular paradigm or in a different era would be incommensurable with science produced in another; that is, there would be no equitable way of comparing them. He identified three kinds of incommensurability: (1) methodological incommensurability, (2) perceptual and observational incommensurability, and (3) semantic incommensurability. To illustrate the meaning of commensurability within a business context, we could ask whether the value of profits was commensurable with the value of distributive justice. In the example, there seems to be little commensurability between the value of profits and justice (whether it be distributive, interactional, procedural, retributive, or social).