Warren's major contention is that judgments of subjective magnitude are not possible, and therefore subjects base such judgments upon physical correlates of the dimension in question. It would appear that Warren's theory will almost surely fail as a comprehensive model, even though it does provide a heuristic account of judgments of loudness and brightness. In order for the theory to succeed, Warren must specify a physical correlate for judgments ofeverysubjective attribute that has yielded orderly data with Stevens's scaling procedures.