cardinalization

However, a variety of alternative mathematical accounts of maximization lend themselves to Von Neumann-Morgenstern cardinalization of utility; and the empirical adequacy of game theory would be called into question only if we thought that people's behavior is not generally describable by means of cardinal VNMufs on a suitably liberal interpretation of these (i.e., as opposed to a narrow interpretation in which VNM utility is defined strictly in terms of EUT).

Game Theory Ross, Don 2006

This bit of logic is the crucial insight behind von Neumann & Morgenstern's (1947) solution to the cardinalization problem.

Game Theory Ross, Don 2006