A little over half a century ago philosophers and psychologists at Harvard shared a single department housed in Emerson Hall, its ground-floor corridor presided over by a seated, slightly frowning Ralph Waldo Emerson in bronze. The psychologists by then could scarcely wait to be free of their old-fashioned colleagues. That came soon enough. For what had psychology, armed with its shiny new tools of empirical inquiry, to do with metaphysics? Did one need philosophical speculation to study sensation, perception, and behavior?
Psychology even then had embraced the physicist Percy Bridgman’s “operationalism,” a philosophical position holding that scientific concepts, such as mass or “mind,” could only be defined by the experimental methods or “operations” that were used to establish their application to things or processes. Where psychologists were concerned, that was as much philosophy as was needed. IQ, accordingly, was simply what intelligence tests measured. Viennese logical positivism, moreover, defined the line between philosophy and psychology. According to its principles, only statements that were true by definition (as in logic or mathematics) or were “empirically verifiable” were meaningful and worthy of study. For the logical positivist, philosophers should be concerned with the “analysis” of concepts in ordinary language (such as “justice”) and the sciences (such as “gravity”); such analyses would clarify these concepts by offering improved definitions of them. The sciences—among them psychology—should investigate only statements that are “empirically verifiable.” The rest, issues in logic and language, are treated, in this view, by philosophy.
After World War II, the chief common concern of psychology and philosophy was “methodology”: like the businessman and his accountant, the philosopher told the psychologist the right way to talk about the numbers he had produced in experiments on the reactions of rats, say, or in compiling the results of intelligence tests. “Mind” remained a forbidden four-letter word in mainstream psychology, to be dealt with (if at all) in quotation marks. The “methodology” of “scientific psychology” grew stricter by the year; its terms and concepts had to have an objective basis and had increasingly to conform to stringent rules for defining scientific concepts by experimental procedures. Methods became a preoccupation: methods for making the subjective objective, the hidden overt, the abstract concrete.
Then, in the late 1950s, came what today is called the “cognitive revolution.” Psychologists like Herbert Simon and George Miller, and linguists like Noam Chomsky, devoted themselves not to their subjects’ overt, objective responses, but rather to what they knew and how they acquired knowledge. The emphasis shifted from performance (what people did) to competence (what they knew). And this inevitably led to the question of how knowledge was represented in the mind. Could you simulate what the mind knew with a computational program (as Simon was attempting to do) or with a theory of mental organization (as Piaget was doing)? “Mind” was being reintroduced into psychology and defined variously as ways in which knowledge was organized, or as a set of strategies for using knowledge in order to achieve intended results …