Cognitivism: Whose party is it anyway?

Christopher D. Green
Department of Psychology
York University

(1994) Canadian Psychology, 35, 112-123


In a recent article, F. I. M. Craik asked the question, "Will cognitivism bury experimental psychology?" His answer was that, rather than being buried by cognitivism, experimental psychology has been abandoned by what he perceived to be the rationalists of cognitive science. Ultimately, however, he argued that cognitive science will have to come back to experimental psychology because psychological questions are empirical and cannot be answered by rationalist means. Using his comments as a point of departure, it is argued in this paper that this belief is based upon a misapprehension about cognitive science. Cognitive science is not rationalist. It is scientific, but redresses an imbalance in the relative regard with which theory and data are typically held by experimental psychologists. It is argued that rather than being buried by, or abandoned by, cognitive science, experimental psychology should merge with the new theoretical renaissance represented by the cognitive scientific movement.


In a recent article in Canadian Psychology, F. I. M. Craik (1991) offered the following observation on the last few decades of development in cognitive science:

At first, psychologists seemed delighted that philosophers, linguists, computer scientists and others were increasing their interest in cognitive phenomena. These feelings were enhanced when neuroscientists also evinced a growing interest in the underlying mechanisms of cognition during the 1980's. As the decade wore on, however, traditional experimental psychologists increasingly found themselves in the position of hosts who have organized a wonderful party only to discover that the many new friends they have invited get on rather too well with each other. So well in fact that they start drifting off in groups, talking animatedly among themselves, and quite forgetting their hosts. By this view, then, cognitivism has not so much 'buried' experimental psychology, but abandoned it; declared it boring, old-hat, and irrelevant.

I agree with Craik that this is the impression many experimental psychologists have of cognitive science. I have heard similar sentiments in seminars, at conferences, and in the halls of the department. I believe however that they are based upon a number of misapprehensions psychologists typically harbour about the histories of the relevant disciplines, and about the relation of theory to data, philosophy to psychology, and rationalism to empiricism.

The aim of this paper is not to respond to Craik specifically, although his comments constitute my point of departure. The aim is to address generally what I take to be traditional psychologists' misapprehensions concerning cognitive science. I will begin by examining the histories of philosophy and computer science with regard to interest in cognitive phenomena. Then I will discuss the place of experimental psychology in the current cognitivist Zeitgeist. What I intend to demonstrate is that, cognitivism was never really psychology's "party" to begin with, and that whatever feelings of resentment there have been are misplaced. I will argue that experimental psychology is not, in principle, "boring, old-hat, and irrelevant", nor does anyone really believe it to be. The problem is a practical one: experimental psychology is often carried out without reference to current cognitive theorizing in philosophy and computer science. The work of experimental psychologists is, thus, often found to be of little importance to cognitive scientists. Since experimental psychology, the institution, holds no exclusive claims on cognitive psychology, the topic, cognitive science continues its work without much reference to traditional experimental psychology.

1. Recent History of the Component Disciplines of Cognitive Science.

First, let us look at the histories of the disciplines most central to cognitive science. Among the most proud and confident proclamations one reads in histories of psychology are those beginning with the words, "When psychology parted ways with philosophy and became an experimental science..." What seems not often to be recognized is that during the intervening century or so since the time that psychology is thought to have gone its own way, philosophical psychology has been going strong, running on a parallel course. The two have been influencing each other and informing each other at each step along the way, though open acknowledgement of philosophical psychology has been notably lacking among experimental psychologists. This silence had been due in part to simple ignorance, in part to willful tendentiousness.

By "philosophical psychology", I do not refer to psychoanalysis or any other treatment-oriented psychological practice. These are sometimes labelled "philosophical" by experimental psychologists. This, I believe, is a mistake. Neither psychoanalysis nor any of its psychodynamic derivatives, up to and including the humanism of the 1970s, were intended primarily as philosophical discourse. I refer, instead, to the work of mainstream positivistic and post-positivistic philosophers. These include Ludwig Wittgenstein, Rudolf Carnap, Gilbert Ryle, Carl Hempel, W. V. O. Quine, Roderick Chisholm, U. T. Place, D. M. Armstrong, Wilfred Sellars, Peter Geach, J. J. C. Smart, Paul Feyerabend, and Hilary Putnam, to name just a few. While psychology was still off in the wilds of behaviourism -- radical and neo-, metaphysical and methodological -- philosophers were attempting grapple explicitly with questions of cognition and mentality; questions that experimental psychologists had sometimes banned outright.

There were, of course, exceptions. Behaviourism never took as strong a hold in social psychology and developmental psychology as it did in learning. Perception researchers had a sometimes uncomfortable relationship with behaviourism, often mouthing the necessary fiction that they were only studying the correlation between the stimulus type or intensity and the behavioural (rather than perceptual), response. Even among learning theorists, there were heated debates about just how much about the mental was to be denied. These debates notwithstanding, for a long while it seemed that only Piaget, Bartlett, and the Gestalt psychologists, all Europeans were there to reminded us in North America that trial and error is not the only path to knowledge. By the 1950s, psychologists such as Hebb, Broadbent, and Bruner had begun what would ultimately become cognitive psychology, but they were much in the minority.

Among philosophers, however, there was a much richer diversity of opinion. Hempel (1935/1980), Carnap (1932-1933/1990), Wittgenstein (1946-1948/1980), Ryle (1949), and Quine (1960) were, of course, behaviourists of various sorts, and with various degrees of reservation. It would be a mistake, however, to equate their varieties of behaviourism with those put forward by Watson, Tolman, Hull, and Skinner. Hempel and Carnap were driven to behaviourism by details of their logical positivism; details that were probably not of great importance to experimental psychologists (see Smith, 1986, on the new view of the relationship between behaviourism and logical positivism). Wittgenstein (1953/1958), while denying that we develop a private language by reference solely to our mental experience did not go so far as to deny mental experience, per se.

Place (1956), Smart (1959/1970), Feigl (1960/1970), and Armstrong (1965/1970, 1968), alternatively, attempted to identify mental state types with neurophysiological state types, rather than rewrite them in terms of behavioural "dispositions". It was primarily out of their failure to make such an identity stick that contemporary "token identity" theory (Davidson, 1970; Fodder, 1972/1980) emerged. And then, from the marriage of token identity theory and Putnam's (1960) analysis of the Turing machine, contemporary computational functionalism was born.

Chisholm (1957, 1963; Sellars & Chisholm, 1958), on the other hand, was attempting to grapple with the problem of intentionality, at a time when most experimental psychologists had never even heard of the term in its psychological context, or of its modern originator, Franz Brentano (1874/1973). If anything is clearly cognitive, it is intentionality.

Perhaps most the most intriguing work among these mid-century philosophers is the incipient representationalism found in the writings of Peter Geach (1957). Though he is perhaps the least well known among current psychologists of both the philosophical and experimental persuasions there is much in his analyses of mental acts that is strikingly contemporary. As David Hills (1981) writes about Geach's critique of Ryle's theory of belief, "but for its bookishness, [it could] have come from Fodor's discussion of the explanation of action" (p. 16).

The upshot of the preceding is that many of the phenomena now gathered together under the rubric, "cognition" were at issue in philosophical psychology long before (certainly North American) experimental psychology had returned from its behaviourist foray. Behaviourism was a part of philosophical psychology, but it seems that philosophers as a group were far less willing to accept both the unpalatable consequences of strong behaviourism and the inconsistencies of weaker versions than were experimental psychologists. Thus, philosophical psychology has at least as strong a claim to the title of "host" of the cognitive "party" as does experimental psychology.

What about computer science, and more particularly, research concerned with the development artificial intelligence (AI)? Here again, we find that at mid-century AI researchers were far more willing than their counterparts in experimental psychology to talk in unadulterated cognitive terms. McCulloch and Pitts (1943/1965) entitled the paper that might be considered to be AI's inaugural paper, "A logical calculus of the ideas immanent in nervous activity." While it is clear even from the title that McCulloch believed a model of the brain's electronic structure would result in the creation of a mind, it is equally clear that he was a mental realist. Consider McCulloch's "Machines that think and want" (1950/1965), or his, "Why the mind is in the head" (1951/1965). McCulloch (1945/1965) also invented the term "nervous net" now better known as "neural net" to describe his style of machine architecture.

Alan Turing (1950), too, argued that computers could be considered to be intelligent, in just the same ways that humans are. Although he is not always consistent on the point, it seems that he understood that the crucial relation is between the functional, rather than the structural, architecture of the brain and the machine. That is, it is not the kind of machine that matters (within certain parameters) to whether or not it is intelligent, but the kind of program it is running. Hilary Putnam (1960/1975) formalized this relation into the mind-is-to-brain-as-software-is-to-hardware maxim we know today.

With the arrival of the 1960s came a shower of attempts to explicitly model mental processes computationally. One of the most influential models was Rosenblatt's (1959, 1962) perceptron; a "neural net" that was able to learn to recognize shapes visually.

Another highly influential project was Newell, Shaw, and Simon's program, Logic Theorist (LT). It was able derive theorems in the propositional calculus of Whitehead and Russell's Principia Mathematica (1910-1913). Gardner (1985) reports that it actually constructed a proof of one theorem more elegant than that given in the Principia itself. According to the story, Newell submitted the proof to the Journal of Symbolic Logic with LT as a co-author, but the article was turned down. Building on the success of LT, Newell and Simon (1963) constructed the more sophisticated, and better-known, General Problem Solver (GPS), dubbed by its authors, "a program that simulates human thought". It could not only solve logic problems, but symbolically integrate functions, play a variety of games, and a host of other things as well.

There were many other cognitive computational projects soon after, and by the 1970s many trained experimental psychologists were involved in attempts to model the phenomena of their areas of specialization computationally, as well. Mathematicians and computer scientists, however, had gotten a head start of at least a decade on the computational modelling of cognitive processes. By this I do not mean to imply that psychologists never could, or even never did, catch up; only that cognition was a concern of AI researchers long before many psychologists had gotten into the computational act.

It is instructive to recall the recent history of linguistics as well, although I expect that the details are known to most experimental psychologists. Skinner's (1957) attempt to explain language use in behaviouristic terms was savaged by Noam Chomsky (1959), who proved that no simple S-R theory could account for certain kinds of syntactic structures found in all natural languages. Some psychologists, most notably George Miller, moved to test Chomsky's ideas experimentally, but acceptance of Chomsky's approach a fully-developed theoretical approach in the psychological community was slow in coming, and is resisted by many even today.

At this point, I think it is instructive to revise Craik's characterization of the cognitivist "party". You will recall that he suggested that psychology had thrown a terrific party, but was spurned by its guests, who found each other more interesting than their host. In light of the above review of the historical facts, however, another characterization comes to mind. Psychology once lived in this grand old house, but was charmed by the Spartan spirit of behaviourism and moved out, leaving the house more or less abandoned. Others philosophers, computer scientists, and some linguists took up residence and fixed it up. One day, years later, experimental psychology was walking through its old neighborhood and saw its old home, looking newly renovated and modern, and decided to return. Being very impressed by the goings-on inside, it tried to convince the "squatters" that it was the true owner, but no one really took it very seriously and they all went on doing whatever they had been doing before.

2. The Relation Between Cognitive Science and Experimental Psychology.

Craik concludes that the worry that cognitivism will bury experimental psychology, "stems from a concern about the rationalist, non-empirical bias of much of current cognitive science" (p. 443). Moreover, he continues, "both cognitive science and computer science must ultimately appeal to the psychological level of description if they wish their theories to reflect what humans actually do" (p. 443).

I agree with both of these statements, but not perhaps in the way Craik would want me to. The worry that cognitivism will bury experimental psychology does stems from a concern about what is widely perceived to be a rationalist, even anti-empirical, bias in current cognitive science. I would argue, however, that what is going on is not properly characterized as "bias", at least not in its usual pejorative sense. What is going on is a corrective to a long-standing imbalance in the relative importance experimental psychologists have given to theory and data.

Psychologists, to my mind, are full of misapprehensions about what function theories serve in science, and their relation to data. The relation is one of logical interdependence. Data in and of itself cannot make science "go". Data must bear on a theory in order to be of use to science. If all you want is data, why not count the socks in your top drawer, or count licence plates at the main intersection in town? "Because," the answer immediately comes, "that data is not relevant." But relevant to what? To a theory, of course, about some aspect of the world. Without a theory to be related to, data is just so many socks in your drawer. As one of the great scientists of the century, Sir Arthur Eddington, said, perhaps slightly satirically, "It is always a good rule not to put too much confidence in experimental results until they have been confirmed by theory."

Many will immediately counter that theory is just as dependent on data. Where would one get a theory, and how would one know when to modify it, unless one had data? This is true enough, although the processes by which theories are abduced are unremittingly mysterious at present. More importantly, the dependence of theory on data is an aspect of science well-recognized by experimental psychologists as a group. The dependence of data on theory is not. Observe that experimental psychology students are required to take literally hundreds of hours of courses in experimental design and statistical analysis; all means of gathering and analyzing data. They are required to take virtually nothing on the design of theories however. The very devaluation of theoretical papers, in favor of experimental reports, when it comes to questions of publication in experimental psychology dramatically exemplifies the situation.

It might be argued that experimental psychology has a journal of theoretical psychology: the APA's Psychological Review. There are many difficulties here, however. First, that Psychological Review is the only journal, among the APA's dozens, that features theory is a good indication of the degree of seriousness with which theory is taken by the largest, most influential, psychology organization in the world. Second, even Psychological Review rarely devotes space to the theoretical issues that occupy the much-maligned "rationalists" of cognitive science, even though theory-construction and theoretical critique is the rationalist endeavour, par excellance. Compare the articles typically found in Psychological Review with those found, for instance, in Mind, the pre-eminent journal of philosophical psychology.

Experimental psychologists often point to other sciences when defending their empirical imperatives, but the results of such pointing does not bear out their claims. Some physicists, for instance, do nothing but theorize (Einstein, for one). They leave the experimental work to others. The same is true in other sciences as well. Craik has suggested (personal communication) that the science of ethology is largely atheoretical, or at least a science that is data-driven to a degree commensurate with psychology. Though I am no expert in ethology, I would counter that ethology employs the Darwinian paradigm to guide its observational choices no less than any other branch of biology. It is the dynamics of natural selection that are thought to bring about fixed-action patterns and the like. Experimental psychology, however, has no such broad theoretical basis to serve as its guide.

André Kukla (1989) has argued for a theoretical branch of psychology presumably with resources, programmes, and academic positions commensurate with those in experimental psychology but none has shown any sign of appearing. Consequently, theoretical psychology is carried out largely in other disciplines: philosophy, computer science, and linguistics. If this makes experimental psychologists nervous that their topic is being swept out from under them, then the way to counter the trend is to reclaim it themselves, but this they seem unwilling to do.

Craik's second claim, the general thrust of which I take to be that non-empirical cognitive scientists will ultimately have to compare their theoretical speculations with psychological data if they are to have their theories confirmed, may well be true, but just as experimental psychologists have no patent on the topic of psychology, so they have no exclusive rights to its data either. To begin with, psychological data is all around us and, in certain circumstances, all a theoretician need do to confirm an empirical premise contained in his or her argument is to look around. A full-blown experiment is needed only when the required data are of an obscure or otherwise indiscernible nature. Psychology has made a whole discipline of ferreting out this sort of material, but it is not always necessary. Consider, for instance, the empirical data of the psychology of language. Occasionally researchers need to know, for instance, the minutia of reaction times. Much of linguistic data, however, is available all around us, and an experiment serves primarily to legitimize, in the eyes of the institution, what we all already know to be true.

Perhaps more to the point, however, to the degree that experimental psychologists have attended to theoretical concerns at all, they have largely been satisfied to experiment on their own theories rather than on those offered by philosophical and computational cognitive science. It is my own opinion, though by no means only my own, that the theoretical statements emanating from experimental psychology are typically narrow in scope, domain-specific, and consequently not often of a great deal of interest to the cognitive generalist. Moreover, there is a general sense that, because of their lack of theoretical training, experimental psychology's theories are often logically muddled. This is a difficult claim to document, particularly without unfairly singling out individuals as scapegoats. Even if I were to hold an example or two up to scrutiny, I would likely only be accused of having intentionally selected particularly poor examples of psychological theorizing. In any case, certainly not all theoretical work experimental psychology is without merit.

Still, it is a widespread feeling in the community of philosophical psychologists that experimental psychologists' theories are all too often problematic. As far back as the 1940s Wittgenstein (1953/1958) remarked that, "in psychology there are experimental methods and conceptual confusion" (p. 232). To cite an early, but more recent, opinion of Jerry Fodor's:

I think many philosophers secretly harbor the view that there is something deeply (i.e., conceptually) wrong with [experimental] psychology, but that a philosopher with a little training in the techniques of linguistic analysis and a free afternoon could straighten it out. (1968, p. vii)

Admittedly, Fodor's "afternoon" has turned into an entire career, but I suspect that his opinion of experimental psychology, as well as that of many of his colleagues, has not changed much in the intervening 25 years. Deep conceptual difficulties still plague the field.

Consequently, it is not surprising that experimental psychologists find themselves feeling as though they have been declared "boring, old-hat, and irrelevant." Many of them have maintained such an isolationist stance with respect to psychological research being carried on in related disciplines that they are not thought of as part of the current cognitive research program. Those experimental psychologists who are, tend to call themselves "cognitive scientists" instead. Cognitive scientists are by and large perfectly happy to live and let live on this point, but they are in no way beholden to experimental psychologists when it comes to their own research. To Craik's claim that they must ultimately return to experimental psychologists for data, the answer is "well, yes and no" They can take what they find useful from experimental psychology's results, and glean the rest on their own. If doing this makes them experimental psychologists in their own right, then so be it. What they do not need to do is depend on the institution of experimental psychology to get it. What will bury the institution of experimental psychology, though not the topic, is continuing to regard with suspicion and some fear the theoretical branch of its own discipline, which is on the rise in philosophy, computer science, and linguistics departments across the continent.

3. Conclusions.

I have argued, in effect, that cognitivism was not experimental psychology's "party" to begin with. Philosophers, computer scientists, and linguists were interested in, and conducted research on, cognitive issues long before experimental psychology returned to claim what it took to be it rightful heritage. I do not, however, think that this spells the burial of experimental psychology.

I think it should signal, however, a change in its fundamental approach. Experimental psychology, from the days of Watson to the present, has carried on a sort of cold war with philosophy. This was ill-advised from the beginning, and is nothing less than downright anti-intellectual today. Philosophers of mind, of language, of logic, and of science are precisely the friends experimental psychologists need to renovate the discipline. The irreplaceable value of theory and theoretical pursuits needs to be recognized by the institutions of the discipline: the departments, programs, journals, associations, and funding agencies.

Because experimental psychologists are not, even today, trained in computational techniques as a matter of course, the relationship with computer science has been ambivalent at best. This should end. The computer should become a basic tool of theoretical modelling in psychology. This does not commit one to "psychological computationalism" anymore than computational modelling of the weather commits the meteorologist to "meteorological computationalism". The computer is the basic tool with which scientists in physics, chemistry, biology, demography, and a host of other disciplines, examine the implications of their theories. By turning one's psychological theory into a computer program one ensures that it has been stripped of a host of pre-theoretical intuitions and assumptions that have often been found to infect major psychological theories in the past -- often after years of research. This is of critical import because, after all, theories are supposed to serve the purpose of formalizing and ultimately allowing us to explain our intuitions, not just restate them.

Adhering to psychological computationalism, over and above this, is a matter of theoretical and metaphysical taste. Knowing about it, however, and being able to discuss in an informed manner its relative merits (and demerits) should be mandatory at this stage in the psychology's development, just as knowing the details of, say, punctuated equilibrium is mandatory among evolutionary biologists, whether one believes it or not.

Experimental psychology should not be "buried" by cognitive science but should merge with it. The disciplines complement each other in important ways and, together, form a much stronger scientific front than they do individually. At the risk of sounding a little idealistic, I believe it is time for the interdisciplinary prejudices of the past to be dropped in favor of a renewed mutual interest and understanding. Better still, I think that, regardless of their "home" discipline, cognitive psychologists (as well as cognitively-oriented linguists, philosophers, and computer scientists) should take it upon themselves to become acquainted with the insights that each of cognitive science's component disciplines has to offer. The ability to employ the discoveries and the research tools of the discipline-next-door can only make one a better scientist. There is nothing radical in this. All I am calling for, from my perspective, is good scholarship. The good scholar seeks out many points of view on the topic of his or her interest, critically selects the most valuable insights he or she comes across, and attempts to synthesize them into a coherent explanatory account of the question at hand. The bigger that question, the more intellectually significant the account.


Armstrong, D. M. (1968). A materialist theory of mind. London: Routledge & Kegan Paul.

Armstrong, D. M. (1970). The nature of mind. In C. V. Borst (Ed.), The mind-brain identity theory (pp. 67-79). London: Macmillan. (Original work published 1965)

Brentano, F. (1973). Psychology from an empirical standpoint (A. C. Rancurello, D. B. Terrell, & L. L. McAlister, Trans.). New York: Routledge & Kegan Paul and Humanities Press. (Original work published 1874)

Carnap, R. (1932-33). Excerpt from "Psychology in physical language". In W. Lycan (Ed.) (1990). Mind and cognition: A reader (pp. 23-36). Oxford: Basil Blackwell. (Original work published 1932-1933)

Chisholm, R. M. (1957). Perceiving: A philosophical study. Ithaca, NY: Cornell University Press.

Chisholm, R. M. (1963). Notes on the logic of believing. Philosophy and Phenomenological Research, 24, 195-201.

Chomsky, N. (1959). Review of Skinner's Verbal behavior. Language, 35, 26-58.

Churchland, P. M. (1988). Matter and consciousness (rev. ed.). Cambridge, MA: MIT Press.

Craik, F. I. M. (1991). Will cognitivism bury experimental psychology? Canadian Psychology, 32, 440-443.

Davidson, D. (1970). Mental events. In L. Foster & J. W. Swanson (Eds.), Experience and theory (pp. 79-101). Amherst, MA: University of Massachusetts Press.

Dennett, D. C. (1978). Intentional systems. In D. C. Dennett (Ed.), Brainstorms: Philosophical essays on mind and psychology (pp. 3-22). Cambridge, MA: MIT Press.

Dennett, D. C. (1987). The intentional stance. Cambridge, MA: MIT Press.

Feigl, H. (1970). Mind-body, not a pseudo-problem. In C. V. Borst (Ed.), The mind-brain identity theory (pp. 33-41). London: Macmillan. (Original work published 1960)

Fodor, J. A. (1968). Psychological explanation: A introduction to the philosophy of psychology. New York: Random House.

Fodor, J. A. (1980). What psychological states are not. In Representations: Essays on the foundations of cognitive science (pp. 79-99). Cambridge, MA: MIT Press. (Original work published 1972)

Fodor, J. A. (1987). Psychosemantics: The problem of meaning in the philosophy of mind. Cambridge, MA: MIT Press.

Gardner, H. (1985). The mind's new science: A history of the cognitive revolution. New York: Basic Books.

Geach, P. (1957). Mental acts. London: Routledge & Kegan Paul and Humanities Press.

Hempel, C. (1980). The logical analysis of psychology. In N. Block (Ed.), Readings in philosophy of psychology (Vol. 1, pp. 14-23). Cambridge, MA: Harvard University Press. (Original work published 1935)

Hills, D. (1981). Introduction: Mental representation and the languages of thought. In N. Block (Ed.), Readings in philosophy of psychology (Vol. 2, pp. 11-20). Cambridge, MA: Harvard University Press.

Kukla, A. (1989). Nonempirical issues in psychology. American Psychologist, 44, 785-794.

McCulloch, W. S. (1965). A heterarchy of values determined by the topology of nervous nets. In Embodiments of mind (pp. 40-45). Cambridge, MA: MIT Press. (Original work published 1945)

McCulloch, W. S. (1965). Machines that think and want. In Embodiments of mind (pp. 307-318). Cambridge, MA: MIT Press. (Original work published 1950)

McCulloch, W. S. (1965). Why the mind is in the head. In Embodiments of mind (pp. 172-141). Cambridge, MA: MIT Press. (Original work published 1951)

McCulloch, W. S. & Pitts, W. H. (1965). A logical calculus of the idea immanent in nervous activity. In Embodiments of mind (pp. 19-39). Cambridge, MA: MIT Press. (Original work published 1943)

Neisser, U. (1967). Cognitive psychology. Englewood Cliffs, NJ: Prentice-Hall.

Newell, A. & Simon, H. A. (1963). GPS, a program that simulates human thought. In Feigenbaum, E. A. & Feldman, J. (Eds.), Computers and thought (pp. 279-293). New York: McGraw-Hill.

Place, U. T. (1956). Is consciousness a brain process? British Journal of Psychology, 47, 44-50.

Putnam, H. (1975). Minds and machines. In Mind, language and reality (pp. 362-385). Cambridge, Eng.: Cambridge University Press. (Original work published 1960)

Quine W. V. O. (1960). Word and object. Cambridge, MA: MIT Press.

Rosenblatt, F. (1959). Two theorems of statistical separability in the perceptron. In Mechanisation of thought processes: Proceedings of a symposium held at the National Physical Laboratory, November, 1958 (Vol. 1, pp. 412-456). London: HM Stationery Office.

Rosenblatt, F. (1962). Principles of neurodynamics. New York: Spartan.

Ryle, G. (1949). The concept of mind. New York: Barnes & Noble.

Sellars, W. & Chisholm, R. M. (1958). Intentionality and the mental. In H. Feigl, M. Scriven, & G. Maxwell (Eds.), Minnesota Studies in the Philosophy of Science: Concepts, theories, and the mind-body problem (pp. 507-539). Minneapolis: University of Minnesota Press.

Skinner, B. F. (1957). Verbal behavior. New York: Appleton-Century-Crofts.

Smart, J. J. C. (1970). Sensation and brain processes. In C. V. Borst (Ed.), The mind-brain identity theory (pp. 52-66). London: Macmillan. (Original work published 1959)

Smith, L. D. (1986). Behaviorism and logical positivism: A reassessment of the alliance. Stanford, CA: Stanford University Press.

Turing, A. (1950). Computing machinery and intelligence. Mind, 59, 434-460.

Whitehead, A. N., & Russell, B. (1910-1913). Principia mathematica. Cambridge: Cambridge University Press.

Wittgenstein, L. (1958). Philosophical investigations. Oxford: Basil Blackwell. (Original work published l953)

Wittgenstein, L. (1980). Remarks on the philosophy of psychology (2 vols., G. E. M. Anscombe, Trans., G. E. M. Anscombe & G. H. von Wright, Eds.). Chicago: University of Chicago Press. (Original manuscripts written 1946-1948)

Author Note

Requests for reprints should be directed to Christopher D. Green, Department of Psychology, York University, North York, Ontario, CANADA, M3J 1P3. I would like to thank Gus Craik and André Kukla for their comments and suggestions concerning earlier drafts of this paper.