 Uljana Feest considers that operationism did leave a lasting and positive legacy in psychology. The maxim of operationism dictates that psychologists should provide concepts with operational definitions by specifying paradigmatic experimental conditions for their application, and this remains a useful methodological tenet (Feest 2011, 403). In Feest’s view a sufficiently sophisticated understanding of operationism in psychology was only reached by the second generation of operationists, who consciously employed what she calls the methodological (rather than positivist) reading of operationism. Feest’s analysis reinforces R. C. Grace’s (2001) view that the early operationist psychologists made the mistake of adopting a very restrictive version of Bridgman’s ideas, but that this mistake was corrected in the 1950s with the adoption of “multiple” or “convergent” operationism. These sophisticated operationists did not take operational definitions to give full and fixed meanings of concepts, but used them as provisional tools aiding their scientific investigations. As Feest puts it: “I believe that in offering operational definitions, scientists were partially and temporarily specifying their usage of certain concepts by saying which kinds of empirical indicators they took to be indicative of the referents of the concepts.”(Feest 2005, 133; emphases original)