Gary Hatfield

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.

During the 1630s Descartes recognized that he could not expect all legitimate claims in natural science to meet the standard of absolute certainty. The realization resulted from a change in his physics, which itself arose not through methodological reflections, but through developments in his substantive metaphysical doctrines. Descartes discovered the metaphysical foundations of his physics in 1629-30; as a consequence, the style of explanation employed in his physical writings changed. His early methodological conceptions, as preserved in the Rules and sketched in Part Two of the Discourse, pertained primarily to his early work in optics. By the early 1630s, Descartes was concerned with new methodological problems pertaining to the postulation of micro-mechanisms. Recognition of the need to employ a method of hypothesis led him to lower the standard of certainty required of particular explanations in his mature physics.

Reprint of: Gary Hatfield, Force (God) in Descartes' physics, Studies in History and Philosophy of Science Part A 10 (2):113-140 (1979) Abstract. It is difficult to evaluate the role of activity - of force or of that which has causal efficacy - in Descartes’ natural philosophy. On the one hand, Descartes claims to include in his natural philosophy only that which can be described geometrically, which amounts to matter (extended substance) in motion (where this motion is described kinematically).’ Yet on the other hand, rigorous adherence to a purely geometrical description of matter in motion would make it difficult to account for the interactions among the particles that constitute Descartes’ universe, since the notions of extension and kinematical motion do not in themselves imply any causal agency. There is, after all, no reason to expect that a particle whose single essence is extension, even if we suppose it to be moving, should impart motion to another particle, while conversely, there is no reason to expect a resting particle to hinder the motion of an impinging one. Descartes' hankering for an austere ontology of matter in motion is in danger of excluding causal agency (force, conceived dynmically) from matter. To the modern reader it may seem obvious that Descartes did not get himself into such a fix, since matter in motion so readily reminds us of kinetic energy or of some more primitive notion of force. Yet by no means is it obvious that Descartes attributed causal efficacy to matter in motion per se. Serious scholars have held opposite positions on this issue. Westfall, Gabbey, and others’ have argued that although on the metaphysical plane Descartes attempted to eliminate force from his mechanical universe, nonetheless ‘force is a real feature’ of his mechanical world. The thrust of this view is that Descartes conceived of force as ‘the capacity of a body in motion to act’, by means of impact, upon other bodies. An opposing interpretation, defended here, is that Descartes did in fact deny causal agency to moving matter per se, restricting agency to immaterial substances such as the human mind, angels, and God. The intention of this interpretation is not to de-emphasize the role of matter in motion in Descartes’ explanation of nature, but rather to stress the fact that Descartes did not conceive of this moving matter dynamically.

Twelve subjects provided shape and orientation judgments for a set of projectively equivalent, variously rotated rectangles under three viewing conditions—monoptic, dichoptic, and binocular—with and without the presence of a pattern mask. In the absence of the mask, partial constancy was exhibited under the first two conditions and near perfect constancy under the binocular condition. Orientation was discriminated. Presence of the mask produced projective shape matching and diminished orientation discrimination. It is argued that the site of masking was postchiasmal, and the results are related to previous work with pattern masking of projectively equivalent ellipses.

In a backward masking paradigm Epstein, Hatfield, and Muise (1977) found that presentation of a frontoparallel pattern mask caused the perceived shape of elliptical figures which were rotated in depth to conform to a projective shape function. The current study extended the masking function by examining the effect of a mask which was partially or wholly cotemporal with the target. The study also assessed the functional equivalence of the masking treatment and the conventional treatment for minimizing depth information. Reports of perceived shape and perceived orientation were obtained under three conditions: binocular without mask, binocular with mask, monocular without mask. Under the first condition, perceived shape conformed to objective shape and perceived orientation was proportional to objective orientation. Under the latter two conditions, perceived shape was in very close agreement to projective shape and the two functions did not differ. Orientation was underestimated greatly under both conditions. We concluded that the effect of the mask on perceived shape is mediated by its effect on encoding of orientation information, although an additional effect on the subsequent stage of shape-slant integration cannot be excluded.

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.

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.

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.).

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.

The quantitative experimental scientific psychology that became prominent by the turn of the twentieth century grew from three main areas of intellectual inquiry. First and most directly, it arose out of the traditional psychology of the philosophy curriculum, as expressed in theories of mind and cognition. Second, it adopted the attitudes of the new natural philosophy of the scientific revolution, attitudes of empirically driven causal analysis and exact observation and experimentation. Third, it drew upon investigations of the senses. Natural philosophical disciplines such as optics and acoustics treated the functioning of the senses. Optics, in particular, had from antiquity comprised a complete theory of vision, combining the physics, physiology, psychology, metaphysics, and epistemology of vision, using mathematical techniques where feasible. Within medicine, sensory physiology examined anatomy, physiology, and pathology. Philosophical psychology had long examined the senses as mental capacities connected with cognition and knowledge, and such discussions also heeded the new attitudes of natural philosophy. This chapter first examines the early relations of psychology to biology and characterizes various eighteenth-century loci of psychological thought. It then pursues nineteenth-century developments in Germany and Britain that culminate in the “new” psychology of the 1860s and 1870s.

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 introductory chapter surveys some basic findings on primate evolution and the evolution of mind; examines socially transmitted traditions in relation to the concept of culture; recounts the sources of evidence regarding the evolution of mind and culture; charts the history of evolutionary approaches to mind and behavior since Darwin; reviews several prominent theoretical syntheses concerning the evolution of the human mind and behavior; and, along the way, introduces the specific questions examined in the individual chapters.

This article seeks the origin, in the theories of Ibn al-Haytham (Alhazen), Descartes, and Berkeley, of two-stage theories of spatial perception, which hold that visual perception involves both an immediate representation of the proximal stimulus in a two-dimensional ‘‘sensory core’’ and also a subsequent perception of the three dimensional world. The works of Ibn al-Haytham, Descartes, and Berkeley already frame the major theoretical options that guided visual theory into the twentieth century. The field of visual perception was the first area of what we now call psychology to apply mathematics, through geometrical models as used by Euclid, Ptolemy, Ibn al-Haytham, and Descartes (among others). The article shows that Kepler’s discovery of the retinal image, which revolutionized visual anatomy and entailed fundamental changes in visual physiology, did not alter the basic structure of theories of spatial vision. These changes in visual physiology are advanced especially in Descartes' Dioptrics and his L'Homme. Berkeley develops a radically empirist theory vision, according to which visual perception of depth is learned through associative processes that rely on the sense of touch. But Descartes and Berkeley share the assertion that there is a two-dimensional sensory core that is in principle available to consciousness. They also share the observation that we don't usually perceived this core, but find depth and distance to be phenomenally immediate, a point they struggle to accommodate theoretically. If our interpretation is correct, it was not a change in the theory of the psychology of vision that engendered the idea of a sensory core, but rather the introduction of the theory into a new metaphysical context.

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

In the Aristotelian curriculum, De anima or the study of the soul fell under the rubric of physics. This area of study covered the vital (“vegetative”), sensitive, and rational powers of the soul. Descartes’ substance dualism restricted reason or intellect, and conscious sensation, to human minds. Having denied mind to nonhuman animals, Descartes was required to explain all animal behavior using material mechanisms possessing only the properties of size, shape, position, and motion. Within the framework of certainty provided by the metaphysical foundations of his physics, he posited such mechanisms in accordance with appropriately lessened standards of certainty. As Cartesianism (or the Cartesian revolution) spread, adherents offered survey textbooks or treatises of physics to replace the corresponding Aristotelian curriculum. These books typically discussed the role of experience in physics and the appropriate standard of certainty. A comprehensive Cartesian natural philosophy needed to mechanize the offices of the Aristotelian sensitive soul, including sense perception, memory, and cognitive and appetitive responses to the environment. Descartes’ Treatise on Man (1664) offered an initial explanatory program. This chapter examines the role of experience in the natural philosophy and mechanistic psychology of Descartes’ English follower Antoine Le Grand. He offered detailed accounts of the sensory and motor mechanisms shared by human and nonhuman animals (for which he claimed “physical certainty”). These frame his Cartesian psychology.

During the seventeenth century the major cognitive faculties--sense, imagination, memory, and understanding or intellect--became the central focus of argument in metaphysics and epistemology to an extent not seen before. The theory of the intellect, long an important auxiliary to metaphysics, became the focus of metaphysical dispute, especially over the scope and powers of the intellect and the existence of a `pure' intellect. Rationalist metaphysicians such as Descartes, Spinoza, and Malebranche claimed that intellectual knowledge, gained independently of the senses, provides the framework for constructing a new theory of nature. Other writers, including Hobbes and the early Gassendi, denied the existence of a distinct intellectual faculty, and so challenged the metaphysicians' abilities directly to perceive the essences of substances. The theory of the senses, which had long been a part of philosophical discussion, took on a new urgency, for adherents of the new corpuscularian philosophy needed to replace the dominant Aristotelian theory of real sensory qualities and sensible species. The revival of skepticism and a renewed interest in method also brought the faculties into prominence, for skeptical challenges typically were directed toward the faculties of sense and understanding, and the theory of method was conceived as providing instructions for the proper use of one's cognitive equipment. The theory of the faculties, then, is an important key to theories of knowledge in the seventeenth century. Indeed, rather than speaking of seventeenth century epistemology, it would be less anachronistic and more informative to speak of theories of cognition. The familiar (and over-stated) point that epistemology became fundamental to metaphysics during that century can then be restated as the point that the theory of faculties became central in metaphysical dispute.

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.

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.

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.

Descartes boldly claimed: "I think, therefore I am." But one might well ask: Why do we think? How? When and why did our human ancestors develop language and culture? In other words, what makes the human mind human? _Evolution of Mind, Brain, and Culture_ offers a comprehensive and scientific investigation of these perennial questions. Fourteen essays bring together the work of archaeologists, cultural and physical anthropologists, psychologists, philosophers, geneticists, a neuroscientist, and an environmental scientist to explore the evolution of the human mind, the brain, and the human capacity for culture. The volume represents and critically engages major theoretical approaches, including Donald's stage theory, Mithen's cathedral model, Tomasello's joint intentionality, and Boyd and Richerson's modeling of the evolution of culture in relation to climate change. The volume contains chapters by: Peter Carruthers; Thierry Chaminade; Philip Chase; Merlin Donald; Peter Gardenfors; Gary Hatfield; Jody Hey; Steven Mithen; April Nowell; Peter Richerson and Robert Boyd; Theodore Schurr; Robert Seyfarth and Dorothy Cheney; Kim Sterelny; and Felix Warneken. ISBN 978-1-934536-49-0

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.

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.

The chapter examines some common assumptions regarding the shape of the history of theories of mind. It questions the conception that the Scientific Revolution resulted in placing the mind “outside of nature.” During the seventeenth century, the followers of Descartes routinely placed study of the mind, or, at least, mind–body interaction, within “physics” considered as a science of nature in general (and so including physics in the narrow sense, biology, and psychology). By the end of the eighteenth century, many authors treated the psychological and the physical as distinct areas of investigation (with points of contact, to be sure), both amenable to natural scientific study. Another assumption is that, prior to behaviorism, the notion of “the psychological” was equivalent to “the mental.” And yet, during the seventeenth century psychological phenomena were assigned to both sides of the mind–body divide: the Cartesians and their allies offered (nonmentalistic) mechanistic explanations for the sensory and behavioral capacities that human beings share with animals, while also holding that some aspects of mental life (including consciousness, free will, conceptual language, and general intelligence) require an immaterial mind. Finally, from the late eighteenth century onward, some have maintained that if mental states are reached only by introspection then they cannot be studied objectively. The chapter argues that the standard version of this objection misunderstands the nature of introspection, and it mounts a reply founded on Wundt’s methodological discussions and making reference to the perceptual investigations of the Gestalt psychologists.

Rene Descartes and William James had "body first" theories of the passions or emotions, according to which sensory stimulation causes a bodily response that then causes an emotion. Both held that this bodily response also causes an initial behavioral response (such as flight from a bear) without any cognitive intervention such as an "appraisal" of the object or situation. From here they differ. Descartes proposed that the initial processes that produce fear and running are entirely mechanical. Even human beings initially run from the bear as a result of physiological processes alone, without mental contribution. These physiological processes also cause a mental passion, which is a cognitive representation of the situation (as regards novelty, benefit, or harm), and which motivates the will to continue the behavior already in progress. According to James, emotions are caused by instinctive bodily responses that are triggered by noncognitive but nonetheless conscious perceptual states. Emotions are bare feelings of internal physiological stirrings that accompany an instinctual response that has evolved through Darwinian natural selection. Jamesian emotions initially have no motivational or cognitive content, which they subsequently acquire through learning. The methodological legitimacy of comparing these positions across the centuries is defended, and the two theories are compared to recent theories.

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.

Descartes set for himself the ambitious program of accounting for the functions of the Aristotelian vegetative and sensitive souls without invoking souls or the faculties or powers of souls in his explanations. He rejects the notion that the soul is hylomorphically present in the organs of the body so as to carry out vital and sensory functions. Rather, the body’s organs operate in a purely mechanical fashion. That is what is involved in “mechanizing” these phenomena. The role of the soul is restricted to properly mental functions: to the conscious aspects of sensations and other mental operations; to intellectual acts; and to acts of volition. In effect, soul becomes mind. In order to understand the extent of Descartes’ ambition, this chapter first considers more fully the functions attributed to the soul or to the vital faculties in the Aristotelian and Galenic traditions, and especially the functions of the sensitive soul or power. It draws attention to the cognitive aspects of these functions, beyond the mere operation of the external senses. Then it turns to Descartes’ mechanistic explanations for these cognitive functions. Finally, it situates Descartes’ new mechanistic psychology within the larger context of his novel anthropology, or theory of the human being.