The tripartite model of representation

Transcription

1 PHILOSOPHICAL PSYCHOLOGY, VOL. 15, NO. 3, 2002 The tripartite model of representation PETER SLEZAK ABSTRACT Robert Cummins [(1996) Representations, targets and attitudes, Cambridge, MA: Bradford/MIT, p. 1] has characterized the vexed problem of mental representation as the topic in the philosophy of mind for some time now. This remark is something of an understatement. The same topic was central to the famous controversy between Nicolas Malebranche and Antoine Arnauld in the 17th century and remained central to the entire philosophical tradition of ideas in the writings of Locke, Berkeley, Hume, Reid and Kant. However, the scholarly, exegetical literature has almost no overlap with that of contemporary cognitive science. I show that the recurrence of certain deep perplexities about the mind is a systematic and pervasive pattern arising not only throughout history, but also in a number of independent domains today such as debates over visual imagery, symbolic systems and others. Such historical and contemporary convergences suggest that the fundamental issues cannot arise essentially from the theoretical guise they take in any particular case. if men had been born blind philosophy would be more perfect, because it would lack many false assumptions that have been taken from the sense of sight. (Galileo Galilei, 1610) Mental representation: the topic for some time now Robert Cummins (1996, p. 1) has recently characterized the vexed problem of mental representation as the topic in the philosophy of mind for some time now. However, this remark is something of an understatement. In fact, the same topic was central to the famous controversy between Antoine Arnauld and Nicolas Malebranche in the 17th century, and also central to the entire philosophical tradition of ideas in the writings of Locke, Berkeley, Hume, Reid and Kant. This pattern of recurrence is a striking fact. However, the cognitive science literature has almost no overlap with that of the history of early modern philosophy. This mutual neglect is remarkable in view of the intimate connection of their concerns. I am concerned here to reveal something of the rich and mutually illuminating connections between these disjoint literatures. In principle, such mutual illumination can make a valuable and perhaps novel contribution both to contemporary cognitive science and also to the scholarship of early modern philosophy. The possibility of mutual bene t is even Peter Slezak, Program in Cognitive Science, School of History & Philosophy of Science, University of New South Wales, Sydney, NSW 2052, Australia, p.slezak@unsw.edu.au ISSN /print/ISSN X/online/02/ Ó 2002 Taylor & Francis Ltd DOI: /

2 240 P. SLEZAK more evident when we notice that the parallels extend beyond merely having common concerns. That is, not only the problems of the 17th century, but the same solutions are being rehearsed today at the forefront of research in cognitive science. Descartes déjà vu: Edelman s Traité de l homme A preliminary indication of the modern relevance of early philosophy may be seen in Edelman s (1998) work on perception. Despite its concern with the latest theories of perception, the central problem is stated in terms identical with that of the entire tradition of writers on ideas since the 17th century. Edelman writes: Advanced perceptual systems are faced with the problem of securing a principled (ideally, veridical) relationship between the world and its internal representation. Edelman s bold new solution is a call for the representation of similarity instead of representation by similarity. However, this might have been taken verbatim from Descartes s Traité de l homme (1662/1972) or Dioptrics (1637/1985) where he said the problem is to know simply how [images] can enable the soul to have sensory perceptions of all the various qualities of the objects to which they correspond not to know how they can resemble these objects (Descartes, 1637/1985, pp. 1, 165). In the same vein as Edelman, Meyering (1997) points out that, despite its advocates today (Wright, 1993), resemblance cannot be analyzed without circularity. As we will see, this issue arises inescapably as part of a deeper problem concerning the nature of representation. The tripartite schema In a recent article, Bechtel (1998, p. 299) states the essentials of a modern theory of representation: There are three interrelated components in a representational story: what is represented, the representation, and the user of the representation. Z: System Using Y Y: Representation X: Thing Represented Bechtel s schema articulates a tripartite conception of ideas as representatives intervening between the mind and the world. As we will see, among the problematic assumptions, Bechtel s diagram (modi ed here) and discussion crucially fail to distinguish internal and external representations (see Abell & Currie, 1999). Importantly, Bechtel s conception in this regard is not idiosyncratic, but accurately re ects an almost universal conception in cognitive science (Dennett, 1978a; Lloyd, forthcoming; Newell, 1986, p. 33; Rumelhart & Norman, 1983). As we will note presently, the same tripartite conception in the case of the pictorial theory of images inherently involves the same assimilation of internal and external representations, and thereby encourages the illegitimate postulate of a user or external observer the notorious homunculus. I will suggest that the same tacit assimilation of external and internal representations is at the heart of Searle s (1980) refutation of symbolic AI and also leads to the doctrine that we think in language (Carruthers, 1996; Slezak, 2002). The assimilation just noted in Bechtel will also be seen in the seemingly unrelated problem of consciousness and the mind body problem (Place, 1956). The

3 THE TRIPARTITE MODEL OF REPRESENTATION 241 tripartite scheme appears obvious and innocuous enough, though it has been remarkably fraught with dif culties. Indeed, the inescapability and ubiquity of this picture in one form or another is apparent from the fact that Bechtel s diagram is a variant of the scheme which we see throughout the long history of the subject. The vision of all things in God Thus, for example, nothing could seem more remote from modern theories in cognitive science today than Malebranche s (1712/1997) 17th century doctrine of the vision of all things in God the theory that ideas are objects of our perception that exist in God s mind. On the contrary, however, despite the theological trappings, it is instructive to recognize the profound af nity of Malebranche s views with those at the very forefront of theorizing today in psychology and arti cial intelligence: Malebranche s theory is just Bechtel s tripartite model (Nadler, 1992), and the modern problem of representation is how to avoid the notorious dif culties clearly articulated by his critic Arnauld (1683/1990). Although these parallels need to be defended with detailed argument and exegesis, it is signi cant that Fodor has occasionally made the af nities explicit. Recently he suggests that his own Representational Theory of the Mind (RTM) may be understood on the model of the classical empiricist conception: Just for the purposes of building intuitions, think of mental representations on the model of what Empiricist philosophers sometimes called Ideas. That is, think of them as mental particulars endowed with causal powers and susceptible of semantic evaluation. (Fodor, 1998, p. 7) In this light, it is hardly surprising that modern problems might be simply the reinvention of old problems in a new guise. Fodor endorses the classical conception of ideas though he rejects a conception of representation by means of resembling images. He says To a rst approximation, the idea that there are mental representations is the idea that there are Ideas minus the idea that Ideas are images (1998, p. 8). Despite such disclaimers, we will see that there is particular irony in the fact that the problem for images may be, at a deeper level, the problem for Fodor s RTM as well. Independently of Fodor s explicit allusion, his conception of a representational theory of mind has always been evocative of traditional accounts. Thus, it may be just a façon de parler, but Fodor s (1978) analysis of propositional attitudes has consistently been expressed in terms of relations between organisms and internal representations which are sentence-like entities (1978, p. 198), that is, formulae in an Internal Representational System (1978, p. 194) and whose intentional contents refer to things in the world. Fodor earlier explained this idiom by the same analogy with traditional theories: This is, quite generally, the way that representational theories of the mind work. So in classical versions, thinking of John (construed opaquely) is a

4 242 P. SLEZAK relation to an idea viz., to an internal representation of John. (1978, p. 200) Fodor speaks of internal representations as the immediate objects of beliefs, thereby revealing the close similarity of his theory with the classical Lockean theory of ideas as the immediate objects of perception. This conception of internal representations as being in a relation to a person is an explicit tripartite scheme which Fodor takes to specify a priori conditions on propositional attitudes. This may be, at best, an awkward locution and, at worst, encouraging a notoriously problematic theory. It is important to acknowledge that Fodor and Bechtel, like most theorists, are fully aware of the fatal problem lurking here in principle. However, awareness of the problem in principle does not necessarily preclude falling victim in practice. For example, we will see that proponents of pictorial imagery have been repeatedly charged with committing the homunculus error. Notwithstanding their advocates protestations of innocence [1] and full awareness of the hazards, there are grounds for seeing pictorial theories as problematic in the traditional manner. The charge is that the representational format cannot be made to work without tacitly invoking the very abilities it is supposed to explain (Pylyshyn, 1973, 1978, 1981, in press; Slezak, 1992, 1995, in press). The error is not con ned to imagery and is made unwittingly by failing to notice that the accessing mechanisms cannot perform their function on their own in view of the particular properties ascribed to the representation. As Bechtel (1998, p. 299) notes, a process which uses a representation as stand in must be coordinated with the format of the representation. However, the nature of the format may be such as to require a user which is not merely a process in an innocuous sense. Speci cally, taking internal representations to be too closely modeled on our external representational artifacts clearly risks requiring the user to share our relevant perceptual and cognitive abilities, thereby begging the question in the traditional manner. We will see that the assimilation of internal and external representations in just this way is frequently made as an explicit doctrine. Adverting to the virtues of computational models which ultimately discharge their homunculi and pay back their loan on intelligence (Dennett, 1978b) is not suf cient as a plea of innocence to these charges (Kosslyn et al., 1979). As Rorty (1979, p. 235) has put it, there is no advance in replacing the little man in the head by a little machine in the head. In particular, I will argue later that the common appeal to an internal symbolic language analogous to a formal system appears to be guilty of the same charge. The dispute, then, is about whether the theoretical models succeed in avoiding the well-known dif culty despite their authors intentions. Thus, although rejecting the charge of being ontologically promiscuous (1978, p. 179), Fodor s locution may be symptomatic of the deep dif culties which pervade the problem of representation. Signi cantly, Fodor says that his conception corresponds precisely with the view that psychologists have independently arrived at. To the extent that Fodor is correct in this observation, not only philosophers have been prey to the deeply compelling mistakes of theorizing about the mind. It is no accident that Gibson s ecological approach, like the closely related

5 THE TRIPARTITE MODEL OF REPRESENTATION 243 situated cognition, are theories of direct realism which have been proposed as alternatives to the representationalism of computational theories. This is merely one form in which the Malebranche Arnauld debate is being rehearsed today. This celebrated debate is described by Nadler (1989) as a debate between an object theory of ideas and an act theory, respectively. He explains the object theory of ideas involves a commitment to a representationalist or indirect realist theory of perception, such as Malebranche (and, on the traditional reading, Locke) put forth. An act theory of ideas, on the other hand, forms the core of Arnauld s perceptual direct realism. If ideas are representational mental acts [rather than entities], then they can put the mind in direct cognitive contact with the world no intervening proxy, no tertium quid, gets in the way. (1989, p. 6) As Nadler (1989, p. 6) points out, Malebranche s vision in God is a theologization of cognition according to which the contents of our own thoughts are dependent upon their divine source in the mind of God. However, although Malebranche s theological and epistemological concerns are woven together, the threads may be separated and his doctrine of ideas identi ed as the familiar, compelling and widely held theory until the present time. Although there is room for scholarly dispute [2], most commentators share a reading of Malebranche according to which ideas are intermediaries or proxies representing external objects and intervening between the mind and the world. This same representative theory of perception has been more familiar as John Locke s veil of ideas in the tradition referred to as the way of ideas. On this view, ideas are internal mental objects of some kind toward which the mind s operations are directed. Nadler echoes Bechtel, describing Malebranche s theory as assuming that there are three elements in the normal perception or knowledge of the world (Nadler, 1989, p. 81). As Arnauld explained in his critique, Malebranche regards this representation as being actually distinct from our mind as well as from the object (1683/1990, p. 63). A crucial and frequently quoted passage from Malebranche himself explains: Thus, it does not see them by themselves, and our mind s immediate object when it sees the sun, for example, is not the sun, but something that is intimately joined to our soul, and this is what I call an idea. Thus, by the word idea, I mean here nothing other than the immediate object, or the object closest to the mind, when it perceives something, ie., that which affects and modi es the mind with the perception it has of an object. (1712/1997, p. 217) Situated cognition: the canonical cottage cheese case Signi cantly, John Yolton has expressed a hope that from the study of early thinkers we may be able to understand how we can have representation (cognitivity) and realism too (1996, p. x). This is, of course, a comment on the perennial problem

6 244 P. SLEZAK posed by the tripartite scheme. Yolton s remarks on earlier thinkers is apt to describe the central problem of theories today: The pivotal concept for the accounts of perceptual acquaintance in the seventeenth and eighteenth centuries is that of objects present to the mind. Depending on how that concept was interpreted, those accounts moved between an indirectness of knowledge (because only a representative, proxy object can be present to the mind) and a strong direct realism where the object known was, in some way, itself present to or in the mind. (1984, p. 6) Recent proponents of situated cognition have been complaining of exactly the same indirect, mediated conception in computational theories of cognition, recognizing that these embody essentially the Locke Malebranche s scheme of representations intervening between mind and world. For example, Greeno (1989) unknowingly echoes Arnauld: I am persuaded that in normal activity in physical and social settings, we are connected directly with the environment, rather than connected indirectly through cognitive representations. An individual in ordinary circumstances is considered as interacting with the structures of situations directly, rather than constructing representations and interacting with the representations. (1989, p. 290) Greeno cites the Weight Watcher who had studied calculus but nevertheless answers a question about a daily allotment of cottage cheese by means of a simple, directly physical, operation dividing up a portion of cheese, rather than by any symbolic computation such as a multiplication on fractions. Ergo, reasoning is not symbolic but situated. The Weight Watcher case is supposed to illustrate the thesis that the person s actions are somehow unmediated by mental representations [3]. The cause for Greeno s concern is the modern version of Locke s view: It is evident that the mind knows not things immediately, but only by the intervention of the ideas it has of them (Locke, 1690, Book IV, Chapter IV). Deux Cartésiens: plus ça change, plus c est la même chose It is amusing to notice how Malebranche s attempt to articulate this picture is echoed today by Fodor. Malebranche wrote: I think everyone agrees that we do not perceive objects external to us by themselves. We see the sun, the stars and an in nity of objects external to us; and it is not likely that the soul should leave the body to stroll about the heavens, as it were, in order to behold all these objects. (1712/1997, p. 217) Fodor writes in the same vein: It is, to repeat, puzzling how thought could mediate between behavior and

7 THE TRIPARTITE MODEL OF REPRESENTATION 245 the world The trouble isn t anyhow, it isn t solely thinking that thoughts are somehow immaterial. It s rather that thoughts need to be in more places than seems possible if they re to do the job that they re assigned to. They have to be, as it were, out there so that things in the world can interact with them, but they also have to be, as it were, in here so that they can proximally cause behavior. it s hard to see how anything could be both. (Fodor, 1994a, p. 83) Malebranche and Arnauld are not chosen for mention here at random or merely in retrospect for their current interest. As Gaukroger (1990) has noted, Malebranche s Search after truth was the most in uential philosophical treatise of the second half of the seventeenth century, eclipsed only at the end of that century by Locke s Essay (1690/1964, p. 1). In particular, Malebranche s doctrines were at the center of a famous controversy with Antoine Arnauld whose treatise On true and false ideas (1683) was a reply to Malebranche. Indeed, this debate was not only a major événement intellectuel of its time, as Moreau (1999) has recently described it, but one whose echoes may be heard throughout the subsequent centuries of speculation about the mind. Moreau s (1999) recent book-length study in French is perhaps the rst devoted to the dispute as such, and attests to its importance as an intellectual cause célèbre in the 17th century [4]. Nadler writes that, following the rst round with Arnauld s critique of Malebranche, For the next decade, until Arnauld s death in 1694, these two men engaged in a public debate that attracted the attention of intellectual circles throughout Europe. Sides were taken in articles, reviews and letters in the foremost journals of the day, and the issues were debated by others as hotly as they were by the primary combatants themselves. it remains one of the most interesting episodes in seventeenth-century intellectual history. (1989, p. 2) Nadler adds that the debate is indispensable for understanding the central philosophical issues of the period, and this is especially true in relation to the work of Descartes. As the title of Moreau s (1999) book indicates, Malebranche and Arnauld were, despite their differences, rst and foremost Deux Cartésiens. Arnauld insisted that his conceptions were faithful to those of Descartes and, as Nadler notes, Arnauld would remain committed to la pensée cartésienne for the rest of his life (1989, p. 34). Though differing over the doctrine of ideas and perceptual acquaintance, both accepted the fundamental principles of Descartes s philosophy (Nadler, 1989, p. 59). Arnauld s view takes on special interest today since his critique of Malebranche constitutes a way out of the analogous problematic conceptions of modern cognitive science.

8 246 P. SLEZAK Precursors: pointless exercise? À propos of historical re ections, with some justice, Stephen Gaukroger (1996) in his landmark intellectual biography of Descartes has described as a pointless exercise the efforts to show the extent to which Descartes, for example, was a precursor of modern cognitive science. However, in some cases we may discern something more than fortuitous, independent reinvention. There is a more interesting kind of recurrence which deserves attention because it is a manifestation of deeper, and therefore more illuminating, causes a chronic malaise whose recurrence is symptomatic of deep pathology. Noting anticipations of current theories is likely to be revealing in both directions: precursors of cognitive science provide an independent, extensive source of insight into contemporary issues and, conversely, are themselves elucidated in novel ways unavailable to traditional scholarship. (For preliminary steps in this direction, see Yolton, 1984, 1996, 2000; Slezak, 1999, 2000.) Thus, beyond merely noting the parallels, I would like to offer some preliminary diagnosis of the malaise and its etiology along the lines of Arnauld s defense of Descartes view against Malebranche. Tables & chairs: bumping into things From Yolton s statement of earlier concerns, we can see their relevance to contemporary issues: From the scholastics intelligible species, through the Cartesian s objective reality, to Berkeley s and Hume s talk of ideas as the very things themselves, we see writers on perception striving for some way to say that we perceive physical objects. One of the ways in which some of the writers tried to preserve the accuracy, if not the directness, of perceptual awareness was by talking of a conformity or agreement between ideas and objects; otherwise they said ideas represent objects. (1996, pp. 1 2) This is, of course, just the modern problem of intentionality or psychosemantics which Cummins describes as just that of saying in some illuminating way, what it is for something in the mind to represent something (1996, p. 1). Despite the seeming simplicity of the phenomenon, the burgeoning literature attests to the fact that there is a consensus, at least, on Fodor s judgment that of the semanticity of mental representations we have, as things now stand, no adequate account (1985b, p. 28). Typically, Stalnaker, too, says, There is little agreement about how to do semantics, or even about the questions that de ne the subject of semantics (1991, p. 229). Likewise, B.C. Smith confesses, It should be admitted that how this all works how symbols reach out and touch someone remains an almost total mystery (1987, p. 215). In a report on the state and prospects of interdisciplinary cognitive science, Fodor (1985a) joked that philosophers are notorious for having been prey to absurd, eccentric worries such as the fear that there is something fundamentally unsound

9 THE TRIPARTITE MODEL OF REPRESENTATION 247 about tables and chairs. Nevertheless, he optimistically contrasted such mere philosophical worries with those that occasionally turn out to be real, as with the representational character of cognition. Triumphantly, Fodor points to the fact that today, unlike other proprietary concerns, this problem is no longer just a philosophers preoccupation because its solution has become of general importance as a precondition of progress in several disciplines of cognitive science. However, there is an acute unintended irony in Fodor s contrast, because the problem of representation at the forefront of cognitive science today is, in fact, identical with the philosophical anxiety about tables and chairs. In various more or less independent domains, cognitive scientists have simply rediscovered the very same sterile conundrums which have kept philosophers busy since Descartes. We see a revealing clue to this commonality in Jackendoff s (1992, p. 161) question which is a reductio ad absurdum of contemporary symbolic, computational theories: In view of the internalism and narrow syntactic character of computational symbols, Jackendoff asks facetiously: Why, if our understanding has no direct access to the real world, aren t we always bumping into things? Jackendoff s satire is evocative of Samuel Johnson s famous response to Berkeley s ingenious sophistry : I refute it thus, he said, that is, by kicking a stone. In both cases, appealing to bumping into things, the responses bring into relief the way in which classical and modern theories entail a disconnection of the mind and the world. The suggestive parallel between Jackendoff and Johnson is no accident. Jackendoff captures precisely the paradox charged against Locke and also Malebranche, who Nadler (1992, p. 7) says is often portrayed by his critics as enclosing the mind in a palace of ideas, forever cut off from any kind of cognitive or perceptual contact with the material world. Of course, Berkeley s idealism is just the worry about the reality of tables and chairs, and Berkeley s reaction to Locke s ideas is analogous to Fodor s reaction to Simon s symbols methodological solipsism. Seemingly isolating thought in a realm of its own, the representations intervene between mind and world two items whose systematic connections with each other become mysterious. The traditional problem, rediscovered in cognitive science, is how to make sense of the relation between these three elements mind, representation and world seemingly essential to any model of cognition. The philosophick topick of ideas In his recent book, Yolton (1996, p. 43) mentions the anonymous author of a pamphlet written in 1705 titled Philosophick essay concerning ideas who says, There is hardly any Topick we shall meet with that the Learned have differed more about than that of Ideas. It is a remarkable fact that little has changed in this regard concerning the Topick in dispute, the underlying reasons for the problem and the solutions adopted [5]. Although the terminology of ef uvia, essences, modes and substances has been replaced by information processing jargon, the essential issues are unchanged. Thus, Palmer s (1978) article on Fundamental aspects of cognitive representation says Anyone who has attempted to read the literature related to cognitive representation quickly becomes confused and with good reason. The

10 248 P. SLEZAK eld is obtuse, poorly de ned, and embarrassingly disorganized. After enumerating a dozen distinct conceptions Palmer adds These are not characteristics of a scienti c eld with a deep understanding of its problem, much less its solution (1978, p. 259). The situation does not appear to have improved in the two decades since Palmer wrote. It is no accident that Palmer s lament and his litany echo Yolton s anonymous author because the theoretical disarray, like the doctrines themselves, are not unrelated. Suf cient evidence of this is the fact that the 18th century author s analysis of the problem and its causes remains appropriate today. in considering the Mind, some men do not suf ciently abstract their Thoughts from Matter, but make use of such Terms as can properly relate to Matter only, and apply them to the Mind in the same Sense as they are spoken of Matter, such as Images and Signatures, Marks, and Impressions, Characters and Notes of Things, and Seeds of Thoughts and Knowledge. (quoted in Yolton, 1956/1993, p. 96) Translated into current terminology, this is an insightful diagnosis of the latest disputes concerning representation in cognitive science today. It is, in fact, a re-statement of Arnauld s orthodox Cartesian view which insists that mental representations cannot be properly characterized in terms taken too directly from those apt for our external, material representations the problem of original versus derived intentionality. Malebranchean Theatre? Dennett s (1991) reference to a Cartesian Theater has given wide currency to this term and thereby served to draw attention to the supposed provenance of a conception which is, indeed, at the heart of philosophical puzzles about the mind and consciousness. Indeed, the related mistakes of the Theater and the homunculus are at the heart of much theorizing in cognitive science. However, fully acknowledging the value of Dennett s analysis, it remains that his terminology, at least, perpetuates an historical solecism. Conceding that Dennett was not concerned with exegetical, scholarly niceties, it remains important to correct a serious error of misattribution. The Theater in question is more appropriately ascribed to Malebranche than to Descartes. Although Malebranchean Theater does not have the same pleasing sonority, there is good philosophical reason to correct the usage besides mere historical pedantry. It is important to recognize that a commitment to the picture of an inner person observing a scene on the stage of consciousness is independent of, and does not follow directly from, dualism. Dennett recognizes this in his talk of Cartesian materialism (1991, p. 107) which he says is the view you arrive at when you discard Descartes dualism but fail to discard the imagery of a central (but material) Theater where it all comes together. However, Dennett seems to blame Descartes for holding this Theater conception together with, or directly as a consequence of, his dualism. Nevertheless, contrary to Dennett s implication, while undeniably a Cartesian dualist, Descartes was emphatically not a Cartesian materialist as well. That is, he was not guilty of the Theater fallacy in this

11 THE TRIPARTITE MODEL OF REPRESENTATION 249 sense. On the contrary, despite positing the anatomical convergence of nerve laments in the pineal gland, Descartes did not subscribe to the picture of an observer in the problematic Theater because he explicitly argued against positing concomitant representations of a kind which would require the notorious homunculus. Descartes ghost in the machine is not this observer, but a posit based on entirely different, independent considerations namely, the Cogito argument and the limitations of machines (Discourse V). The rationale for Descartes immaterial soul is quite different and independent of the Theater conception which he explicitly repudiates in his Dioptrics (1637) and Treatise of man (1662). Quite apart from the evidence of Descartes own texts, ample support for these ascriptions is found in Arnauld s writings which articulate an act-theory as an alternative to Malebranche s representative veil of ideas (see Nadler, 1989, pp. 34, 118, 126, footnote 36). Arnauld saw this direct perception view as faithful to Descartes, and Descartes says in correspondence that Arnauld has entered further than anyone else into the sense of what I have written (AT III, 331). Thus, Arnauld s Cartesian position adopts precisely Dennett s stance against the Malebranchean Theater. Reinventions: synchronic and diachronic If Malebranche and Arnauld anticipated contemporary concerns about representation in cognitive science, then it is clear that the current theoretical problem has nothing to do with the theoretical framework of symbolic, computational approaches as universally assumed. It is particularly signi cant, then, that the recurrences of interest here are found not only throughout history but in seemingly unrelated domains of cognitive science today. This recurrence of essentially the same dispute in widely varying contexts con rms that the underlying problem does not arise essentially from the special features of any one of them. Given a seductive mistake concerning representation as such, multiple, seemingly independent, reinventions are just what we would expect to nd. I will presently suggest that we may discern the same underlying problem at the heart of notorious disputes such as the Imagery Debate, Searle s Chinese Room conundrum, the thinking-in-languag e debate and a number of others which have been prominent and recalcitrant. No representations? The cognitive revolution of the 1960s was characterized by a renewed recognition of the indispensability of internal representations following their repudiation by Skinnerian behaviorism. There is considerable irony in recent approaches which appear to reject internal representations once again (Brooks, 1991; Clark & Toribio, 1994; Freeman & Skarda, 1990; Greeno, 1989; van Gelder, 1998). Notwithstanding Eliasmith s (1996) claim, these views are not plausibly seen as a return to behaviorism since, strictly speaking, they do not reject internal representations at all (see Markman & Dietrich, 2000). Nevertheless, these approaches and their rhetoric are symptoms of the profound dif culties posed by the phenomena. Particularly in view

12 250 P. SLEZAK of the revolutionary hype associated with the latest fashions, it is sobering to notice that Arnauld s (1683/1990) critique of Malebranche exactly pre gures these recent attacks on representational theories. It is no coincidence that Arnauld s treatise On true and false ideas is concerned to repudiate what he describes as imaginary representations, saying, I can, I believe, show the falsity of the hypothesis of representations (1683/1990, p. 77) for one must not make use of alleged entities of which we have no clear and distinct idea in order to explain the effects of nature, whether corporeal or spiritual (1683/1990, p. 65). Illusions & misrepresentation: curious and melancholy fact In seeking to understand the persistence and recalcitrance of the problems of intentionality, it is instructive to examine one facet of the issue which reveals the seductiveness of the mistake. The problem of misrepresentation has arisen for causal or co-variation theories of intentional content (Dretske, 1986; Fodor, 1994a) since these theories seem to be unable to capture the way a mismatch might arise between a representation and the world. If a mentalese token mouse might be caused not only by mice but also by shrews, then the symbol must ipso facto mean shrew and cannot be in error. It seems not to have been noticed that this modern philosophical problem of misrepresentation is a variant of the well-known classical Argument from Illusion (Reynolds, 2000) which was employed in support of Locke s ideas and A.J. Ayer s (1940) sense-data as the immediate objects of perception. The parallel should not be surprising since, after all, an illusion in the relevant sense (that is, an hallucination) is precisely a misrepresentation. The problem of misrepresentation, then, appears to be one of the loose threads which may be pulled to unravel the rest of the tangled ball (see Slezak, forthcoming). Responding to Ayer (1940), Austin (1962, p. 61) remarked on the curious and melancholy fact that Ayer s position on sense-data echoes that of Berkeley. It is an even more melancholy fact today that Fodor s real problems of representation also echo Berkeley. Questions of veridicality for Locke s ideas and Ayer s sense-data arose from precisely the same assumptions as Fodor s namely, the assumption of being able to compare representations and the world. The earlier Fodorian passage from Malebranche is followed by a paragraph that explicitly articulates the Argument from Illusion : It should be carefully noted that for the mind to perceive an object, it is absolutely necessary for the idea of that object to be actually present to it and about this there can be no doubt; but there need not be any external thing like that idea. For it often happens that we perceive things that do not exist, and that even have never existed thus our mind often has real ideas of things that have never existed. When, for example, a man imagines a golden mountain, it is absolutely necessary that the idea of this mountain really be present to his mind. When a madman or someone asleep or in a high fever sees some animal before his eyes, it is certain that what he sees is not nothing, and that therefore the idea of this animal really

13 THE TRIPARTITE MODEL OF REPRESENTATION 251 does exist, though the golden mountain and the animal have never existed. (1712, p. 217) Illusions in this sense are cases in which the correspondence between representations and world fails misrepresentations of exactly the sort relevant to the contemporary puzzle for symbolic, computational accounts of cognition. In the modern case, as posed by Fodor (1994a) and Dretske (1986), the problem is, given causation between these elements, how to explain the possibility of illusion; in the classical case the problem is, given illusion, how to explain causation. The modern problem of misrepresentation arises because causal or correlational theories don t appear to permit a distinction between true and false representations. If a dog causes a representation of cat in mentalese, on the causal account it must ipso facto count as meaning dog and is, therefore, not a mistaken representation of cat. Conversely, the classical Argument from Illusion, starts from the other end, as it were. Beginning with the distinction between true and false representations, the Argument recognizes that these cannot both be correlated with an external reality, and concludes that in both veridical and non-veridical cases there must be some other object of direct perception, the idea or sense-datum (see Reynolds, 2000). In view of these analogies, therefore, I suggest it is no coincidence that Fodor s (1980) methodological solipsism is strongly evocative of a Berkeleyan idealism. The Malebranche Locke argument for representative ideas recognizes that illusions cannot be caused in the usual way by external objects essentially Fodor s puzzle expressed in reverse: Fodor argues that, if ideas are caused by external objects, we can t have illusions. The parallels here appear to be more than super cial or terminological [6]. My claim is not that the problem of misrepresentation and the Argument from Illusion are directed towards the same ends, but only that they arise from an identical conceptual scheme and are mirror-images of one another: The classical argument asserts: if there are illusions, then there is no direct connection or correlation with the external world (i.e. there must be intermediate objects of perception); conversely, Fodor s argument asserts: If there is a direct connection (i.e. causal correlation) with the external world, then there can be no illusions. These are equivalent contrapositives: if we take I 5 illusion, C 5 correlation, then the Malebranche Locke proposition is [I, C] and the Fodor Dretske proposition is [C, I]. In passing, we may note that a degree of confusion has been introduced in these discussions by the failure to distinguish crucially different kinds of illusion. An illusion in the sense relevant to the argument concerning ideas, sense-data or representations is, strictly speaking, hallucination. However, certain other phenomena commonly referred to as illusions in this context such as mirages or bent sticks in water are not illusory at all in an important sense. These are veridical perceptions of the light patterns entering the eye unlike cognitive errors such as the Müller Lyer illusion. Richard Gregory (1997), for example, has explicitly assimilated these phenomena, but no theory of cognitive processes could explain the illusion in the case of mirages and seemingly bent sticks due to refracted light. Gregory s mistake in this regard is interesting and perhaps no mere mistake. Assuming that our

14 252 P. SLEZAK knowledge of the actual conditions in the world must be used in characterizing mental representations is precisely the seductive error which I am concerned to expose in its various guises. A stick appearing bent in water is a case of the world gone wrong in just the sense of this felicitous phrase used by Fodor, as we will see presently, Truth conditions as explanatory? In both the case of misrepresentation and that of illusion the puzzle arises from a commitment to the tripartite conception in which representations intervene between the mind and the world and are somehow correlated with it. In particular, the questions of veridicality for Locke s ideas arose from the impossibility of any comparison between representations and the world, except from the perspective of an independent outside observer. As Berkeley recognized, the very distinction between true and false ideas cannot be made without comparing representations and the world. Of course, this perspective is unavailable to the mind itself. Correspondingly, an explanatory theory cannot make tacit appeal to such a perspective without committing the homunculus error. This means that the veridicality or otherwise of mental representation does not serve an explanatory role and is, therefore, not a legitimate part of a theory of mind. In Berkeley s idealist response to this problem we can see the precursor to Fodor s problem arising from a commitment to truth conditions for mental representations. Securing the veridical connection between representations and the world through causation simply binds them in such a way as to preclude error and thus causation functions for Fodor in the way that a mysterious correspondence worked for Locke. Of course the problem of explaining error and that of explaining truth are two sides of the same coin. Accordingly, the puzzle of misrepresentation is symptomatic of fundamental problems in the conception of mental representations as semantically evaluable. Fodor is emphatic about the centrality of truth preservation for the computational RTM. Regarding the fact that mental processes tend to preserve semantic properties like truth Fodor says This is, in my view, the most important fact we know about minds; no doubt it s why God bothered to give us any. A psychology that can t make sense of such facts as that mental processes are typically truth preserving is ipso facto dead in the water. (Fodor, 1994a, p. 9) Fodor s dilemma arises from the fact that content doesn t appear to supervene on mental processes and, therefore, semantics isn t part of psychology (Fodor, 1994a, p. 38). My point, then, is of course not that solipsism is true; it s just that truth reference and the rest of the semantic notions aren t psychological categories. (1980, p. 253) It seems that we can t do psychology with the semantic notions, but we can t do

15 THE TRIPARTITE MODEL OF REPRESENTATION 253 psychology without them either. This formulation of Fodor s dilemma is reminiscent of a remark by Dennett in a quite different context in which he explained: psychology without homunculi is impossible. But psychology with homunculi is doomed to circularity or in nite regress, so psychology is impossible. (Dennett, 1978b, p. 123) My suggestion is that Fodor s and Dennett s dilemmas appear to be the same because at root the puzzle of semantics is a version of the homunculus problem. Just as Dennett (1978a, p. 122) pointed out that nothing is intrinsically a representation of anything but only for someone who is the interpreter, so nothing is a misrepresentation for the same reason. That is, Fodor s current problem of misrepresentation might be accounted for by noting that it arises from the demand for tacitly adopting the stance of external interpreter: The very problem itself cannot be coherently formulated except in terms of judgments which are not part of the explanatory enterprise. The veridicality of representations is not a property which can play any role in the functioning of representations or the explanation of them. Like the picture on a jigsaw puzzle, the meaning of representations conceived as semantically evaluable in this way is for our own bene t and not intrinsic to the arrangements of interlocking components. The sense in which a mental representation does its work is not one which requires judgment of its truth-value since this is only possible from the point of view of an observer, the theorist, for whom the representation is construed as an external symbol. The very concern with misrepresentation arises from tacitly adopting a questionable assumption endorsed by Davidson (1975) that having a belief requires also having the concept of belief, including the concept of error. Davidson says someone cannot have a belief unless he understands the possibility of being mistaken, and this requires grasping the contrast between truth and error true and false belief (1975, p. 22). However, it seems that animals might have beliefs even if they are unable to know that they have them and re ect on their truth-value. A cat can surely be correct in thinking that a mouse is in a certain hole without having the concepts of belief and truth. The judgment of truth or error in a belief must be distinguished from merely having a belief which is true or false. We as theorists may judge true and false beliefs (just as we may judge pictorial resemblance) since these are meta-linguistic or second-order beliefs, but truth and error are not intrinsic properties of representations as such, only to the judgments made about them. Cat psychology must be possible without invoking cat epistemology. It is not a big leap from misrepresentation and illusion to notice that images are a species of the same genus. Imagery involves illusory or non-veridical experiences of exactly the sort required for the classical argument for sense-data. The proverbial Pink Elephant of inebriated apprehension is a visual image par excellence, not relevantly different from Malebranche s golden mountain or subjects imaginings in the celebrated experiments of Shepard and Metzler (1971) and Kosslyn (1994). As we will see presently, of course, if my conjectured parallel is warranted, it is perhaps no surprise that the imagery debate has been among the most persistently intractable

16 254 P. SLEZAK disputes in cognitive science also arising from the theorist doing the work of the theory. Twin Earth Putnam s (1975) Twin Earth puzzles, too, seem to be an unnoticed variant on the problem of misrepresentation we saw earlier. In the familiar scenario, instead of my Twin Earth double, we may substitute myself after having been unknowingly transported to Twin Earth. There, like my twin in the original story, I will refer to XYZ as water. However, on this variation of the original scenario my term water now fails to refer correctly rather than being a correct reference with a term having a different meaning. Since my twin and I are identical, the two scenarios must also be indistinguishable. That is, the problem of wide and narrow meaning is just the problem of misrepresentation in another guise. Instead of thinking of Twin Earth, then, we may imagine alternatively that on this earth, God might have switched all H2O to XYZ without my knowledge. Instead of taking the original Twin Earth story as showing that my twin must mean something other than water, we may equally conclude that my use of the term is simply in error when the worlds have been surreptitiously switched. The Twin Earth scenario is, indeed, simply another way of telling Dretske s (1986) story of the magnetic micro-organisms which are fooled into thinking that up is down. Or, in a different case, as Fodor (in Millikan, 1991, p. 161) has put it, it s not the frog but the world that has gone wrong when a frog snaps at a bee-bee. Undoubtedly, if the world is suf ciently perverse, or it is contrived to alter things in certain ways, our concepts may accidentally fail to refer in the usual manner. It is not clear why such possibilities should be of interest to a theory of representation for their description depends on knowledge from a God s Eye perspective available to the theorist. Whether the liquid substance is really XYZ or H2O is known only to the external omniscience of the theorist and has no explanatory role in a theory of representation. In this sense, the philosophical concern with misrepresentation is analogous to the spurious assimilation of mirages and seemingly bent sticks to genuine cognitive illusions, as noted earlier. In both cases, the actual truth about the world is invoked irrelevantly to explain cognition. Philosophers as three-year-olds? Ironically, the mistake I am indicating is not unknown in cognitive science: In the cases of interest here, philosophers are like the three-year-olds and autistics in the much-discussed false belief task of Wimmer and Perner (1983) (see Carruthers & Smith, 1996; Davies & Stone, 1995a,b). Like three-year-olds, philosophers fail to discount what they know to be the truth about the world in their theory of mind. The surreptitious switching of XYZ for H2O, bee-bees for ies or magnetic up for down are ways of making the world go wrong precisely analogous to switching the candy while the child is looking in the false belief paradigm. Knowing how the world really is, philosophers truly ascribe false belief, just as the three-year-olds

17 THE TRIPARTITE MODEL OF REPRESENTATION 255 falsely ascribe true belief. In both cases, belief attributions are independent of any facts about the believer, depending instead on irrelevant external facts about the world. In these cases, the believer s state of mind can remain xed and yet the beliefs can be made to change from true to false by manipulating the world. The child, like the philosopher naively takes this possibility to be relevant to a theory of mind in ascribing mental representations. Justi ed true belief? In case the foregoing analogy may be thought far-fetched or merely whimsical, it is perhaps worth noting en passant that yet another notorious philosophical puzzle may be seen to be merely a version of the same problem. Gettier (1963) paradoxes may be seen as a species of misrepresentation in which the world conspires to make a proposition true for reasons which are entirely independent of a person s grounds for believing it. In these cases the problem can only be described because the theorist knows the truth about circumstances which make a belief accidentally true, even though the actual circumstances are irrelevant to the agent s own reasons for believing the proposition. The Gettier cases are structurally identical with those of misrepresentation and Twin Earth because the truth or falsity of the mental representation (i.e. the state of the world) is varied independently of the agent s belief- xing mechanisms. Such considerations in all cases should be irrelevant to the problem of understanding mental representation. The moral of the Gettier cases, like that of misrepresentation, is that the only sensible, and perhaps the only possible, theory of knowledge is one that invokes justi cations and not truth from a God s Eye perspective [7]. Any adequate, or even complete, account of a person s psychology would have to invoke only the relation of beliefs to available evidence and not their actual, ultimate truth-value. The world can mislead us in various ways, giving us good reasons for things that may be false, bad reasons for things that may be true and good reasons for things that may be true for other reasons. None of this should occasion philosophical anxieties for those interested in psychology. Does the speedometer of a bicycle misrepresent when the bike is ridden on rollers and not moving? Once again, it is the world that has gone wrong, known to us as external observers. However, psychology has no obligation to explain why the world may go wrong. Thus, conceivably, one might contrive things so that Cabernet Sauvignon replaced the usual liquid in someone s veins. However, such a possibility is of no more theoretical concern for medical science than Dretske s (1986) disoriented microbes are of interest to cognitive science. Idea-objects Bechtel s (1998, p. 299) re-statement of the tripartite model in Malebranche s terms makes explicit the widely held assumptions which are the potential source of the dif culties in understanding representation [8]. In particular, Bechtel s assimilation of internal and external representations is acknowledged where he lists the sorts of high-level representations which have been postulated by cognitive scientists.