Gary Hatfield

Representation and content in some (actual) theories of perception -- Representation in perception and cognition : task analysis, psychological functions, and rule instantiation -- Perception as unconscious inference -- Representation and constraints : the inverse problem and the structure of visual space -- On perceptual constancy -- Getting objects for free (or not) : the philosophy and psychology of object perception -- Color perception and neural encoding : does metameric matching entail a loss of information? -- Objectivity and subjectivity revisited : color as a psychobiological property -- Sense data and the mind body problem -- The reality of qualia -- The sensory core and the medieval foundations of early modern perceptual theory -- Postscript (2008) on Ibn al-Haytham's (Alhacen's) theory of vision -- Attention in early scientific psychology -- Psychology, philosophy, and cognitive science : reflections on the history and philosophy of experimental psychology -- What can the mind tell us about the brain? : psychology, neurophysiology, and constraint -- Introspective evidence in psychology.

Descartes’ accounts of sensory perception have long troubled his interpreters, for their lack of clear and explicit statements on some fundamental issues. His readers have wondered whether he allows spatial sensory ideas (spatial qualia); whether sensory ideas such as color or pain are representations and, if so, what they represent; and what cognitive value Descartes attributed to sense perception. Recent discussions take differing stands on the questions just mentioned, and also disagree over Descartes’ account of the externalization of sensory qualities, on the origin and correct analysis of the “material falsity” he attributes to some sensory ideas, and on the value of the “teachings of nature.” Such disagreement should not be surprising, for although sensory perception was an important topic for Descartes, his treatment of these particular issues is not systematic – or at least not apparently so. Generally, there are no proof texts that unequivocally settle questions about Descartes’ views on spatial qualia, the representationality of sensory ideas, their cognitive value, externalization, material falsity, and the status of the teachings of nature. Yet these questions and topics naturally arise from matters about which Descartes is explicit and (reasonably) consistent, regarding the role of the senses in philosophy and everyday life and concerning the nature of minds and ideas. It is, therefore, worthwhile to ask what his positions might have been. This chapter develops answers by considering Descartes’ systematic doctrines on the nature of the mind and its ideas and by combing his statements on sensation and perception for hints about how to apply such principles. The first section reviews some key texts. Succeeding sections develop positions on representationality, cognitive value, externalization, material falsity, and the teachings of nature. Ultimately, I favor an interpretation in which, for Descartes, all sensory ideas represent by resemblance, different kinds of sensory ideas vary in cognitive value, externalization arises through spatial localization, and, with sensory ideas of color and the like, as materially false they do not intrinsically misrepresent but afford occasion for false judgments, which arise as merely apparent, and so not actually legitimate, teachings of nature.

Descartes developed an elaborate theory of animal physiology that he used to explain functionally organized, situationally adapted behavior in both human and nonhuman animals. Although he restricted true mentality to the human soul, I argue that he developed a purely mechanistic (or material) ‘psychology’ of sensory, motor, and low-level cognitive functions. In effect, he sought to mechanize the offices of the Aristotelian sensitive soul. He described the basic mechanisms in the Treatise on man, which he summarized in the Discourse. However, the Passions of the soul contains his most ambitious claims for purely material brain processes. These claims arise in abstract discussions of the functions of the passions and in illustrations of those functions. Accordingly, after providing an intellectual context for Descartes’s theory of the passions, especially by comparison with that of Tho- mas Aquinas, I examine its ‘machine psychology’, including the role of habituation and association. I contend that Descartes put forth what may reasonably be called a ‘psychology’ of the unensouled animal body and, correspondingly, of the human body when the soul does not intervene. He thus conceptually distinguished a mechanistically explicable sensory and motor psychology, common to nonhuman and human animals, from true mentality involving higher cognition and volition and requiring (in his view) an immaterial mind.

Review of _Descartes’s Method of Doubt_, by Janet Broughton. Princeton and Oxford: Princeton University Press, 2002. Pp. xv + 217. H/b £22.95, P/b £10.95. The review characterizes Broughton's book on Cartesian doubt as a work that attends to the philosophical significance of Descartes's work while taking seriously his own aims and the historical context of his arguments. The review considers her extensive examination of the method of doubt and her notion of "dependence arguments" as a way of overcoming the doubt. The latter includes her own distinctive take on what she calls the "I exist" argument.

According to the reading offered here, Descartes' use of the meditative mode of writing was not a mere rhetorical device to win an audience accustomed to the spiritual retreat. His choice of the literary form of the spiritual exercise was consonant with, if not determined by, his theory of the mind and of the basis of human knowledge. Since Descartes' conception of knowledge implied the priority of the intellect over the senses, and indeed the priority of an intellect operating independently of the senses, and since, in Descartes' view, the untutored individual was likely to be nearly wholly immersed in the senses, a procedure was needed for freeing the intellect from sensory domination so that the truth might be seen. Hence, the cognitive exercises of the Meditations, modeled not on the sense- and imagination-based exercises of Ignatius of Loyola, but on the Augustinian procedure of turning away from the senses and imagination to perceive the unpicturable with the fleshless eye of the mind. In accordance with this reading, the function of Descartes' skeptical arguments is not to introduce skepticism so that it can be defeated but to aid the meditator in withdrawing the mind from the senses in order to attend to truths of the pure intellect. These truths then offer the basis for a new natural philosophy, including a new theory of the senses.

This paper examines the claims of the Gestalt psychologists that there was a crisis in experimental psychology ca. 1900, which arose because the prevailing sensory atomism excluded meaning from among psychological phenomena. The Gestaltists claim that a primary motivation of their movement was to show, against the speculative psychologists and philosophers and Verstehen historians, that natural scientific psychology can handle meaning. Purportedly, they revealed this motivation in their initial German-language presentations but in English emphasized their scientific accomplishments for an American audience. The paper finds that: there was a recognized crisis in the new experimental psychology ca. 1900 pertaining especially to sensory atomism; that the Gestaltists responded to the crisis with new experimental findings and theoretical concepts that challenged atomism; in both languages, they raised problems of meaning and discussed the contest with speculative psychology and philosophy only after presenting their scientific case; that they introduced phenomenological observations on meaning and perceptual organization into their psychology but did not develop a theory of meaning or solve philosophical problems; that they argued ‘‘philosophically,’’ that is, using abstract, conceptual arguments; and that this aspect of their cognitive style was not received well by some prominent members of their American audience.

Descartes' Meditations is one of the most widely read philosophical texts and has marked the beginning of what we now consider as modern philosophy. It is the first text that most students of philosophy are introduced to and this Guidebook will be an indispensable introduction to what is undeniably one of the most important texts in the history of philosophy. Gary Hatfield offers a clear and concise introduction to Descartes' background, a careful reading of the Meditations and a methodological investigation of its main themes. As with all the Guidebooks, this is an exemplary companion to any reading of the Meditations. (Note: This edition has been superseded by Gary Hatfield (2014), The Routledge Guidebook to Descartes' Meditations.).

In the philosophy of perception, direct realism has come into vogue. Philosophical authors assert and assume that what their readers want, and what anyone should want, is some form of direct realism. There are disagreements over precisely what form this direct realism should take. The majority of positions in favor now offer a direct realism in which objects and their material or physical properties constitute the contents of perception, either because we have an immediate or intuitive acquaintance with those objects and properties, or because our perceptual states have informational content that represents the properties of those objects (and which is not itself an object of perception and has no specifically subjective aspect). This paper considers various forms of perceptual realism, including, for purposes of comparison, the largely abandoned indirect or representative realism. After surveying the variety of perceptual realisms and considering their various commitments, I introduce some considerations concerning the phenomenology of visual space that cause trouble for most forms of direct realism. These considerations pertain to the perception of objects in the distance and, secondarily, to the perception of shapes at a slant. I argue that one of the lesser known varieties of perceptual realism, critical direct realism, can meet the challenges offered by the facts of spatial perception.

Not long ago the standard view in cognitive science was that representations are symbols in an internal representational system or language of thought and that psychological processes are computations defined over such representations. This orthodoxy has been challenged by adherents of functional analysis and by connectionists. Functional analysis as practiced by Marr is consistent with an analysis of representation that grants primacy to a stands for conception of representation. Connectionism is also compatible with this notion of representation; when conjoined with functional analysis, it provides a means of analyzing psychological systems in term of rules and representations without becoming committed to symbolism. Direct theorists, who rejected the orthodox symbolist conception of representation because it violated their strictures against cognitive mediational mechanisms, should find it possible to accept rules-and-representations and information-processing analyses of the mechanisms of information pickup couched in terms of functional analysis.

There is disagreement over the notion of representation in cognitive science. Many investigators equate representations with symbols, that is, with syntactically defined elements in an internal symbol system. In recent years there have been two challenges to this orthodoxy. First, a number of philosophers, including many outside the symbolist orthodoxy, have argued that "representation" should be understood in its classical sense, as denoting a "stands for" relation between representation and represented. Second, there has been a growing challenge to orthodoxy under the banner of connectionism. Although this connectionist challenge has evoked emotionally-charged rebukes from the symbolist camp, connectionists as a group have not articulated a conception of representation to replace the symbolist view. Nonetheless, most agree on the need for a nonsymbolic notion of representation. This paper advances a "stands for" sense of representation as primary by incorporating it into a general approach to cognitive science consonant with the connectionism. The idea is to marry connectionism to a particular version of functionalism, viz., one that builds its notion of "function" on the similarity between functional analysis in biology and in psychology. It builds on my earlier work adapting and revising Marr's tri-level approach to cognition. My proposal frees Marr's analysis from its moorings in the orthodox symbolic view of representation and allies it with a notion of functional analysis akin to that proposed by Cummins, developed further by Haugeland, and invoked by Millikan and Dretske. Unlike these authors, however, I do not wed representation to a general belief-desire analysis of behavior. Rather, I follow what I take to be the lesson of psychological practice, according to which the investigator does not seek to explain behavior in general but seeks to analyze the cognitive capacities that underlie behavior, such as vision, memory, learning, and linguistic capacities. Accordingly, ascriptions of representational content are made not by working back from belief-desire ascriptions, but in the context of forming psychological models to account for specific cognitive capacities. Because conceptions of representation in cognitive science typically are embedded in a general approach to the study of cognition, arguments for the comparative plausibility of a particular conception of representation must scout these larger frameworks. I therefore begin by characterizing the interlocking set of assumptions that gave life to the orthodox symbolist approach, paying special attention to the complementarity between representation and process that naturally arises from those assumptions. I then consider two versions of an alternative approach to representation: Dretske's and my own. Finally, I urge the merits of the "cognitive capacities" over the "belief-desire" approach to the subject-matter of cognitive science.

This paper examines the origins and legacy of Titchener’s notion of stimulus error in the experimental study of sensory experience. It places Titchener’s introspective methods into the intellectual world of early experimental psychology. It follows the subsequent development of perceptual experimentation primarily in the American literature, with notice to British and German studies as needed. Subsequent investigators transformed the specific notion of a “stimulus error” into experimental questions in which subjects’ attitudes toward their perceptual tasks became independent variables to be manipulated experimentally. Ultimately, these manipulations support a distinction between accessing phenomenal as opposed to cognitive aspects of subjects’ responses to perceived objects.

This chapter examines Russell’s appreciation of the relevance of psychology for the theory of knowledge, especially in connection with the problem of the external world, and the background for this appreciation in British philosophy of the eighteenth and nineteenth centuries. Russell wrote in 1914 that “the epistemological order of deduction includes both logical and psychological considerations.” Indeed, the notion of what is “psychologically derivative” played a crucial role in his epistemological analysis from this time. His epistemological discussions engage psychological factors in the perception of external objects that had been closely examined in the nineteenth century, among other places in J. S. Mill’s response to William Hamilton’s conception of knowledge of the external world. These considerations came to Russell in various ways, including his contact with British Empiricism (Mill, with Berkeley, Hume, and Reid as background), his engagement with Austrian philosophy, his close acquaintance with the philosophy and psychology of William James, and his exposure to contemporary British writings concerning the problem of the external world. The latter writings provide a crucial context within which natural scientific psychology came to be seen as distinct from epistemology and yet as relevant to its concerns.

This edition of the Prolegomena presents Kant's thought clearly by paying careful attention to his original language. An extensive translator's introduction considers the origin and purpose of the Prolegomena, examines Kant's use of the analytic method, compares the structure of the Prolegomena to that of the Critique of Pure Reason, examines Kant's relation to Hume as expressed in this work, briefly surveys the work's reception, and offers a note on texts and translation. Detailed scholarly notes accompany the translation itself.

Seeing happens effortlessly and yet is endlessly complex. Among the most fascinating aspects of visual perception is its stability and constancy. As we shift our gaze or move about the world, the light projected onto the retinas is constantly changing. Yet the surrounding objects appear stable in their properties. Psychologists have long been interested in the constancies. They have asked questions such as: How good is constancy? Is constancy a fact about how things look, or is it a product of our beliefs and judgments about how things look? How can the contents of visual experience be studied experimentally? Philosophers have long been interested in characterizing visual experience and have become widely interested in the constancies more recently. As psychologists and philosophers have interacted, new questions have arisen: If experience is not as of retinal stimulation (proximal mode), but does not always exhibit constancy (or at least not in all respects), how shall we describe this intermediate state? Also, should we regard any departure from constancy as a failure of the visual system, or might it be a reasonable or adaptive response? In what circumstances is seeing highly conditioned by cognitive factors such as background assumptions, and in what circumstances not? Our volume focuses on size constancy and color constancy. It considers methodologies for studying conscious visual perception, efforts to describe visual experience in relation to constancy, what it means that constancy is not always perfect, and the conceptual resources needed for explaining visual experience.

What is cognition? What makes a process cognitive? These questions have been answered differently by various investigators and theoretical traditions. Even so, there are some commonalities, allowing us to specify a few contrasting answers to these questions. The main commonalities involve the notion that cognition is information processing that explains intelligent behavior. The differences concern whether early perceptual processes are cognitive, whether representations are needed to explain cognition, what makes something a representation, and whether cognitive processes are limited to the nervous system and brain or include other bodily structures or the environment itself. After unearthing some root notions of cognition in the development of cognitive psychology and cognitive science, this chapter considers the commonalities and differences just scouted, examines Wheeler’s (2005) reference to Descartes’ works in describing “Cartesian” cognitive theory, finds the real target of situated approaches in classical symbolic cognitive science, and suggests that instead of revisiting that target attention should turn to the varieties of intelligent (adaptive, appropriate, flexible) behavior.

Review of: Stephen Gaukroger: The Collapse of Mechanism and the Rise of Sensibility: Science and the Shaping of Modernity, 1680-1760. Oxford: Clarendon, 2010, pp. ix+505. £47.00 (hb). ISBN 9780199594931. This volume is the second of a projected six-volume work on the shaping of modern cognitive values through the emergence of a scientific culture, a phenomenon that Gaukroger takes to be specific to the West. The volume ranges from Newton’s initial publications on optics to the French Enlightenment and the publication of the <i>Encyclopédie</i> of Diderot and d’Alembert. During this period, the unity within natural philosophy, secured by the view that matter theory should underlie all natural philosophy, is challenged, as is the unity between natural philosophy and physico-theology, the latter unity being the primary source of the cultural legitimacy that had allowed natural philosophy to flourish. The first type of unity was sundered as Newtonian natural philosophy disavowed the requirement that mechanics be united with a microscopic corpuscularian basis. Further, during this period, scientific (or natural philosophical) values first came to dominate the cognitive values of an entire culture, largely through the <i>persona</i> of the <i>philosophe</i> as the embodiment of reason, albeit a sensibilized reason arising from the new non-mechanistic natural philosophy of the mid-eighteenth century and no longer tied to physico-theology. The book does a better job charting the trend toward disunity than it does charting the rise of sensibility.

The Gestalt psychologists adopted a set of positions on mind-body issues that seem like an odd mix. They sought to combine a version of naturalism and physiological reductionism with an insistence on the reality of the phenomenal and the attribution of meanings to objects as natural characteristics. After reviewing basic positions in contemporary philosophy of mind, we examine the Gestalt position, characterizing it m terms of phenomenal realism and programmatic reductionism. We then distinguish Gestalt philosophy of mind from instrumentalism and computational functionalism, and examine Gestalt attributions of meaning and value to perceived objects. Finally, we consider a metatheoretical moral from Gestalt theory, which commends the search for commensurate description of mental phenomena and their physiological counterparts.

According to Kepler and Descartes, the geometry of the triangle formed by the two eyes when focused on a single point affords perception of the distance to that point. Kepler characterized the processes involved as associative learning. Descartes described the processes as a “ natural geometry.” Many interpreters have Descartes holding that perceivers calculate the distance to the focal point using angle-side-angle, calculations that are reduced to unnoticed mental habits in adult vision. This article offers a purely psychophysiological interpretation of Descartes’s natural geometry. In his account of perceived limb position from the Treatise on Man, he envisioned a central brain state that controls ocular convergence and thereby co-varies with the distance from observer to object. A psychophysiological law relates the visual perception of distance to this brain state. Descartes also invokes more traditional theories of distance and size perception based on unnoticed judgments, yielding a hybrid account

A commentary on Dretske, "Change Blindness" (same journal issue). Dretske analyzes standard cases of change blindness as properly being difference blindness, since the eye is in saccade when the change occurs and so the change itself (the event of the change) is not seen. He considers two models of the phenomenon, the object model and the fact model, preferring the latter. In previous work, he had affirmed the object model. I reconsider its merits, first looking more closely at the notion of differences and then making a case for seeing differences nonepistemically, or in Dretske’s “object mode.” I then consider some imagined cases that might rightly be classed as difference blindness in object mode, and offer a further taxonomy of various forms of difference blindness. The concluding section raises a fundamental question about the notion of seeing objects nonepistemically, or in a natural sensory (and hence nonconceptual) way. I do not deny the viability of the concept of nonepistemic perception in general, but I do question the notion that we are correctly thought to see spies and other types of individuals in natural sensory mode. That is, I question whether seeing spy-individuals is properly thought of as a natural sensory representational achievement. In this connection, I suggest that there is a tension in Dretske’s thought between nonepistemic seeing as he originally conceived it (1969) and the naturalized counterparts to that notion developed in his later works (1981, 1995). At least part of the explanation for this tension can be found in the differing methods and aims of his earlier and later work – the earlier work focusing on epistemology and philosophy of science, the later works on philosophy of psychology and a naturalized metaphysics of mind.

This chapter challenges the view that psychology emerged from philosophy about 1900, when each found its own proper sphere with little relation to the other. It begins by considering the notion of a discipline, defined as a distinct branch of learning. Psychology has been a discipline from the time of Aristotle, though with a wider ambit, to include phenomena of both life and mind. Empirical psychology in a narrower sense arose in the eighteenth century, through the application (in Britain and elsewhere) of the observational attitudes of the physical and life sciences to mental phenomena. The experimental psychology of the latter nineteenth century was a transformation of this empirical psychology, although the British version was characterized by new theoretical conceptions (including evolutionary ideas) as well as new empirical techniques. After surveying psychology in and out of universities in this period, the chapter reviews a taxonomy of “schools” of psychology from 1923. Notice of anti-psychological attitudes in British philosophy before and after 1900 is balanced by considering positive conceptions of psychology’s role in connection with epistemology and the problem of the external world.

Kant is the central figure of modern philosophy. He sought to rebuild philosophy from the ground up, and he succeeded in permanently changing its problems and methods. This revised edition of the Prolegomena, which is the best introduction to the theoretical side of his philosophy, presents his thought clearly by paying careful attention to his original language. Also included are selections from the Critique of Pure Reason, which fill out and explicate some of Kant's central arguments, and in which Kant himself explains his special terminology. The first reviews of the Critique, to which Kant responded in the Prolegomena, are included in this revised edition. The volume is completed by a historical and philosophical introduction, explanatory notes, a chronology, and a guide to further reading.

There is disagreement over the notion of representation in cognitive science. Many investigators equate representations with symbols, that is, with syntactically defined elements in an internal symbol system. In recent years there have been two challenges to this orthodoxy. First, a number of philosophers, including many outside the symbolist orthodoxy, have argued that "representation" should be understood in its classical sense, as denoting a "stands for" relation between representation and represented. Second, there has been a growing challenge to orthodoxy under the banner of connectionism. Although this connectionist challenge has evoked emotionally-charged rebukes from the symbolist camp, connectionists as a group have not articulated a conception of representation to replace the symbolist view. Nonetheless, most agree on the need for a nonsymbolic notion of representation. This paper advances a "stands for" sense of representation as primary by incorporating it into a general approach to cognitive science consonant with the connectionism. The idea is to marry connectionism to a particular version of functionalism, viz., one that builds its notion of "function" on the similarity between functional analysis in biology and in psychology. It builds on my earlier work adapting and revising Marr's tri-level approach to cognition. My proposal frees Marr's analysis from its moorings in the orthodox symbolic view of representation and allies it with a notion of functional analysis akin to that proposed by Cummins, developed further by Haugeland, and invoked by Millikan and Dretske. Unlike these authors, however, I do not wed representation to a general belief-desire analysis of behavior. Rather, I follow what I take to be the lesson of psychological practice, according to which the investigator does not seek to explain behavior in general but seeks to analyze the cognitive capacities that underlie behavior, such as vision, memory, learning, and linguistic capacities. Accordingly, ascriptions of representational content are made not by working back from belief-desire ascriptions, but in the context of forming psychological models to account for specific cognitive capacities. Because conceptions of representation in cognitive science typically are embedded in a general approach to the study of cognition, arguments for the comparative plausibility of a particular conception of representation must scout these larger frameworks. I therefore begin by characterizing the interlocking set of assumptions that gave life to the orthodox symbolist approach, paying special attention to the complementarity between representation and process that naturally arises from those assumptions. I then consider two versions of an alternative approach to representation: Dretske's and my own. Finally, I urge the merits of the "cognitive capacities" over the "belief-desire" approach to the subject-matter of cognitive science.

Analytic philosophy arose in the early decades of the twentieth century, with Bertrand Russell and G. E. Moore leading the way. Although some accounts emphasize the role of logic and language in the origin of analytic philosophy, of equal importance is the theme of perception, sense data, and knowledge, which dominated systematic philosophical discussion in the first two decades of the twentieth century in both Britain and America. This chapter examines work on perception and sense data as well as the external world in the analytic tradition in the first half of the twentieth century. After sketching the situation before and just after 1900, it turns to Moore, Russell, and their interlocutors in the teens and twenties, addresses the American scene, looks to subsequent developments in the 1930s and beyond, and finally considers the fates of sense data and the ‘given’ and of the topic of perception more generally.

This article calls into question the notion that seventeenth-century authors such as Descartes and Leibniz straightforwardly conceived the mind as something "outside" nature. Descartes indeed did regard matter as distinct from mind, but the question then remains as to whether he equated the natural world, and the world of laws of nature, with the material world. Similarly, Leibniz distinguished a kingdom of final causes (pertaining to souls) and a kingdom of efficient causes (pertaining to bodies and motions), but the question remains as to whether he equated nature with the second kingdom alone, or included both kingdoms within nature. Although Kant sundered Leibniz's envisioned connection between the two kingdoms, even he did not place mind fully outside nature.

This article critically examines the views that psychology first came into existence as a discipline ca. 1879, that philosophy and psychology were estranged in the ensuing decades, that psychology finally became scientific through the influence of logical empiricism, and that it should now disappear in favor of cognitive science and neuroscience. It argues that psychology had a natural philosophical phase (from antiquity) that waxed in the seventeenth and eighteenth centuries, that this psychology transformed into experimental psychology ca. 1900, that philosophers and psychologists collaboratively discussed the subject matter and methods of psychology in the first two decades of the twentieth century, that the neobehaviorists were not substantively influenced by the Vienna Circle, that the study of perception and cognition in psychology did not disappear in the behaviorist period and so did not reemerge as a result of artificial intelligence, linguistics, and the computer analogy, that although some psychologists adopted the language-of-thought approach of traditional cognitive science, many did not, and that psychology will not go away because it contributes independently of cognitive science and neuroscience.

An understanding of the relationship between metaphysics and natural philosophy - or, as we might now say, between philosophy and science - is fundamental to understanding the rise of the "new science" of the seventeenth century. Twentieth-century scholarship on this relationship has been dominated by the thoughbt of Ernst Cassirer, E. A. Burtt, A. N. Whitehead, and Alexandre Koyre. These authors found a common core in the mathematization of nature, which they ascribed to a common Platonic or Pythagorean metaphysical presupposition, on the part of Copernicus, Kepler, Galileo, and Descartes, that the book of nature is written in mathematical characters. Taking Burtt as its primary stalking horse, this chapter challenges this view by finding significant differences in the relations to metaphysics of major actors such as those just named. It does this in part by recognizing that, in the seventeenth century, metaphysics was an intellectual practice that one engaged in wittingly. By contrast, Burtt adopted a historiographical approach in which metaphysics consists of the nonempirical presupposition of an age (a position advanced by R. G. Collingwood). That approach, although valid within its limits, distorts or omits from consideration the witting practice of metaphysics by figures such as Kepler and Descartes. And it makes metaphysicians of Copernicus and Galileo, who are better classified as a mathematical astronomer and a mathematical natural philosopher and writer on astronomy. The chapter ends with some reflections on purportedly aphilosophical history of science.

The concept of representation has become almost inextricably bound to the concept of symbol systems. the concepts is nowhere more prevalent than in descriptions of "internal representations." These representations are thought to occur in an internal symbol system that allows the brain to store and use information. In this paper we explore a different approach to understanding psychological processes, one that retains a commitment to representations and computations but that is not based on the idea that information must be stored and manipulated in symbol systems. In particular, we suggest that the notion of a symbol system as currently understood construes psychological processes in terms of a specific type of computational system, in which a control function "reads," "interprets," and manipulates discrete entities called "symbols." We argue that other types of computational systems may provide a more appropriate characterization of psychological processes. One implication of our argument is the need to consider the constraints placed on computational theories in psychology by the nature of the computing device itself, the human brain. Perhaps surprisingly, this implication leads us to the conclusion that a "functionalist" conception of psychological processes (discussed below) does not entail that physiology is irrelevant to psychology, as has been maintained by prominent adherents of the symbol-systems approach.