ABSTRACT
A characteristic of much of the development of measurement theory in psychology and the social sciences has been an effort to achieve more powerful scales without sacrificing generality. There are two major aspects to every theory of measurement; on the one hand, there is the formal, logical aspects, and on the other hand, the experimental or operational side. Interesting differences between the scales occur with respect to the assignment of numbers in the process of measurement. If the axioms for an interval scale are satisfied by an attribute, the assignment of any two different numbers to any two different objects is sufficient to fix a unique number for each of all the other objects with respect to this attribute. This is equivalent to the selection of an origin and a unit of measurement. An arbitrary distinction has been drawn, for purposes of exposition, between psychological measurement and psychological scaling on the basis of the axioms that are satisfied.
