The claim to be able to measure psychological attributes was thought to conflict with the Campbellian version of the quantity objection. Almost alone of his generation, Reese sought to defend the measurability thesis by a programme of empirical research. Instead of joining him, mainstream American quantitative psychologists responded in the tradition of Fechner: criticisms were deflected, not faced. Even Comrey's proposal that psychology's quantitative procedures be regarded simply as practical tools was unacceptable to those benefiting by the rhetoric of measurement. Deflecting the quantity objection required neutralising the representational theory's emphasis upon empirical tests of quantitative structure. Operationism provided the key. As a result of the recent revolutions in physics, operationism enjoyed considerable vogue within psychology, where it was interpreted by Stevens as a radical, liberating intellectual force. In Stevens' hands, it seemed to liberate modern psychology from the quantity objection.

Coming at a time of postwar expansion within the discipline, the Handbook of Experimental Psychology (1951), edited by Stevens, was very influential. Chapter 1, entitled ‘Mathematics, Measurement, and Psychophysics’, was written by him. It was the most complete exposition of his theory of measurement.