touch 27 Thirrdly, the straining of the eye 28 The occasions which suggest distance have in their own nature no relation to it 29 A difficult case proposed by Dr. Barrow as repugnant to all the known theories 30 This case contradicts a ...

This book argues that science and metaphysics are closely and inseparably interwoven in the work of Descartes, such that the metaphysics cannot be understood without the science and vice versa. In order to make his case, Thomas Vinci offers a careful philosophical reconstruction of central parts of Descartes' metaphysics and of his theory of perception, each considered in relation to Descartes' epistemology. Many authors of late have written on the relation between Descartes' metaphysics and his physics, especially insofar as the (...) former was intended to justify the latter. Vinci's work does not focus on this relation. It takes as a broad interpretive principle that Descartes wanted to justify a certain picture of matter with his metaphysics, but it focuses its own efforts on the way in which metaphysics and science meet in Descartes' theory of sense-perception. Vinci aims to show that Descartes gave an important positive role to sense-perception in his epistemology, and also that he used his reflections on sense-perception to frame his criticism of previous theories of the sensory qualities of objects. (shrink)

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. (shrink)

Gary Hatfield examines theories of spatial perception from the seventeenth to the nineteenth century and provides a detailed analysis of the works of Kant and Helmholtz, who adopted opposing stances on whether central questions about spatial perception were fully amenable to natural-scientific treatment. At stake were the proper understanding of the relationships among sensation, perception, and experience, and the proper methodological framework for investigating the mental activities of judgment, understanding, and reason issues which remain at the core of philosophical psychology (...) and cognitive science. (shrink)

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. (shrink)

Introduction In 1709 George Berkeley published his first substantial work, An Essay towards a New Theory of Vision. As a contribution to the theory of ...

A survey of Descartes' scientific career from his student days at the Jesuit College of La Flèche to his departure for Sweden in 1649.

In this first book-length examination of the Cartesian theory of visual perception, Celia Wolf-Devine explores the many philosophical implications of Descartes’ theory, concluding that he ultimately failed to provide a completely mechanistic theory of visual perception. Wolf-Devine traces the development of Descartes’ thought about visual perception against the backdrop of the transition from Aristotelianism to the new mechanistic science—the major scientific paradigm shift taking place in the seventeenth century. She considers the philosopher’s work in terms of its background in Aristotelian (...) and later scholastic thought rather than looking at it "backwards" through the later work of the British empiricists and Kant. Wolf-Devine begins with Descartes’ ideas about perception in the _Rules _and continues through the later scientific writings in which he develops his own mechanistic theory of light, color, and visual spatial perception. Throughout her discussion, she demonstrates both Descartes’ continuity with and break from the Aristotelian tradition. Wolf-Devine critically examines Cartesian theory by focusing on the problems that arise from his use of three different models to explain the behavior of light as well as on the ways in which modern science has not confirmed some of Descartes’ central hypotheses about vision. She shows that the changes Descartes made in the Aristotelian framework created a new set of problems in the philosophy of perception. While such successors to Descartes as Malebranche, Locke, Berkeley, and Hume accepted the core of his theory of vision, they struggled to clarify the ontological status of colors, to separate what is strictly speaking "given" to the sense of sight from what is the result of judgments by the mind, and to confront a "veil of perception" skepticism that would have been unthinkable within the Aristotelian framework. Wolf-Devine concludes that Descartes was not ultimately successful in providing a completely mechanistic theory of visual perception, and because of this, she suggests both that changes in the conceptual framework of Descartes are in order and that a partial return to some features of the Aristotelian tradition may be necessary. (shrink)

In this chapter I examine past and recent theories of unconscious inference. Most theorists have ascribed inferences to perception literally, not analogically, and I focus on the literal approach. I examine three problems faced by such theories if their commitment to unconscious inferences is taken seriously. Two problems concern the cognitive resources that must be available to the visual system (or a more central system) to support the inferences in question. The third problem focuses on how the conclusions of inferences (...) are supposed to explain the phenomenal aspects of visual experience, the looks of things. Finally, in comparing past and recent responses to these problems, I provide an assessment of the current prospects for inferential theories. (This paper is reprinted in Hatfield 2009, Perception and Cognition: Essays in the Philosophy of Psychology, Clarendon Press, 124-152.). (shrink)

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. (shrink)

Descartes understood the subject matter of physics (or natural philosophy) to encompass the whole of nature, including living things. It therefore comprised not only nonvital phenomena, including those we would now denominate as physical, chemical, minerological, magnetic, and atmospheric; it also extended to the world of plants and animals, including the human animal (with the exception of those aspects of the human mind that Descartes assigned to solely to thinking substance: pure intellect and will). Descartes wrote extensively on physiology and (...) on the physiology and psychology of the senses. This chapter examines the notions of *physiology* and *psychology* in medical and natural philosophical works of Descartes' day; follows his efforts to bring physiology into his mechanistic idiom; considers the relation between physiology of the animal machine and psychological functions that yield functionally appropriate behavior; goes into his physiology and psychology of vision; and elaborates the tension in Descartes' works between his metaphysically supported micro-corpuscularism and his discussion of the animal machine as an organic unity comprising various functionally and teleologically characterized systems. The chapter draws on Descartes' works in both metaphysics and natural philosophy, including his Treatise on Man (originally published as L'Homme, 1664). (shrink)