For Menger, Value Was a “Bilateral” Relationship Between One Individual and One Economic Good, But for Mises, Value Was a “Trilateral” Relationship Involving One Individual and Two Economic Goods

In the few passages that he devotes to value theory in his money book, Mises decisively elaborates on Menger’s somewhat vague definition of value as “the importance that individual goods or quantities of goods attain for us because we are conscious of being dependent on command of them for the satisfaction of our needs.” In Menger’s definition, value was a bilateral relationship between one individual and one economic good. By contrast, in Mises’s exposition, value was a trilateral relationship involving one individual and two economic goods. Mises in fact discussed the value of one good always in explicit context with the value of another good with which it was compared, and he stressed that this “comparison” was based on choice insofar as it involved “acts of valuation.” In his words:

Every economic transaction presupposes a comparison of values. But the necessity for such a comparison, as well as the possibility of it, is due only to the circumstance that the person concerned has to choose between several commodities.

--Jörg Guido Hülsmann, introduction to the third edition of Epistemological Problems of Economics, by Ludwig von Mises (Auburn, AL: Ludwig von Mises Institute, 2003), xxxvi.