Du point de vue méthodologique et épistémologique, la vision occupe une place privilégiée dans les œuvres de Galien de Pergame, ce qui explique les tentatives répétées de ce dernier pour en expliquer le fonctionnement. En partie grâce à la dissection et à la vivisection pratiquées sur des animaux de différentes espèces, il développa une connaissance détaillée de l’anatomie de l’œil, du nerf optique, du cerveau, des muscles oculaires et du système vasculaire cérébral et oculaire. Il utilisa avec habileté cet impressionnant (...) savoir anatomique pour élaborer une explication détaillée de la physiologie de la vision. Pour expliquer comment voient les êtres humains, il fit également appel à l’optique mathématique, notamment à l’optique euclidienne. Cependant, en dépit d’efforts remarquables pour intégrer anatomie, physiologie et mathématiques dans une unique théorie cohérente de la vision, une analyse plus attentive montre que son explication de la vision n’est pas exempte de lacunes non négligeables, de difficultés non résolues et de tensions internes. (shrink)

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. (shrink)

There is no systematic physiology of the eye within Alexander of Aphrodisias' commentary on Aristotle's De Sensu that would match the work of Galen in this area because Alexander is interested in the principles that (as he sees it) guide the work of medical researchers rather than the messy detail of the work itself. If he was aware of Galen’s work in this area, his criticisms of the coalescence theory of vision as set out in the Timaeus is a sufficient (...) answer at the level of philosophical principle, and the inadequate anatomical detail in Alexander’s own physiology of vision reflects that outlook. Alexander’s physiology is not ultimately to be judged against the criterion provided by the model of Galen’s dissection-based research. (shrink)

This book explores the interrelationships between optics, vision and perspective before the Classical Age, examining binocularity in particular. The author shows how binocular vision was one of the key juncture points between the three concepts and readers will see how important it is to understand the approach that scholars once took. In the Middle Ages and the Renaissance, the concept of Perspectiva – the Latin word for optics – encompassed many areas of enquiry that had been viewed since antiquity as (...) interconnected, but which a erwards were separated: optics was incorporated into the field of physics (i.e., physical and geometrical optics), vision came to be regarded as the sum of various psycho-physiological mechanisms involved in the way the eye operates (i.e., physiological optics and psychology of vision) and the word ‘perspective’ was reserved for the mathematical representation of the external world (i.e., linear perspective). The author shows how this division, which emerged as a result of the spread of the sciences in classical Europe, turns out to be an anachronism if we confront certain facts from the immediately preceding periods. It is essential to take into account the way medieval scholars posed the problem – which included all facets of the Latin word perspectiva – when exploring the events of this period. (shrink)

Descartes was born in La Haye (now Descartes) in Touraine and educated at the Jesuit college of La Fleche` in Anjou. Descartes’modern reputation as a rationalistic armchair philosopher, whose mind–body dualism is the source of damaging divisions between psychology and the life sciences, is almost entirely undeserved. Some 90% of his surviving correspondence is on mathematics and scientific matters, from acoustics and hydrostatics to chemistry and the practical problems of constructing scientific instruments. Descartes was just as interested in the (...) motions of matter as in the supernatural soul, and he advised against spending too much time on metaphysical inquiries which neglect imagination and the senses. After meeting the Dutch engineer Isaac Beeckman in 1618, Descartes became committed to a systematically ‘mechanical’account of nature. This involved explaining all natural processes in terms of interactions between microscopic material bodies in motion. Descartes modelled his physics and cosmology on the behaviour of fluids, which also have a distinctive and central role in his physiology: the key processes for natural philosophical investigation are the circulation and mutual displacement of constrained bodies, rather than the isolated collisions of atoms in a void. Descartes settled in Holland in 1628, and commenced an ambitious programme of physiological research. In 1630 he was ‘studying chemistry and anatomy simultaneously’, and in late 1632 he was ‘dissecting the heads of various animals’, in order to ‘explain what imagination, memory, etc. consist in’. By late 1633 Descartes had almost completed L’homme, the Treatise on Man; but he abandoned plans to publish it along with a work on matter theory and optics which relied on Copernican cosmology, after he heard of the condemnation of Galileo. L’homme was published posthumously in 1662 (Latin) and 1664 (French); not until 1972 was it fully translated into English. L’homme draws on many (mostly unnamed) Renaissance medical writers, and covers, firstly, a range of traditional physiological topics, such as digestion and respiration.. (shrink)

Love, fear, hope, calculus, and game shows-how do all these spring from a few delicate pounds of meat? Neurophysiologist Ian Glynn lays the foundation for answering this question in his expansive An Anatomy of Thought, but stops short of committing to one particular theory. The book is a pleasant challenge, presenting the reader with the latest research and thinking about neuroscience and how it relates to various models of consciousness. Combining the aim of a textbook with the style of a (...) popularization, it provides all the lay reader needs to know to participate in the philosophical debate that is redefining our attitudes about our minds. Drawing on the rich history of neurological case studies, Glynn picks through the building blocks of our nervous system, examines our visual and linguistic systems, and probes deeply into our higher thought processes. The stories of great scientists, like Ramon y Cajal, and famous patients, like Sperry's split-brained epileptics, illuminate the scientific issues Glynn selects as essential for understanding consciousness. Some might argue that his lengthy explorations of natural selection overemphasize evolutionary explanations of psychological phenomena, but they must also agree that evolutionary psychology has distanced itself mightily from social Darwinism in recent years and merits a reappraisal. The great consciousness debate may form the core of the 21st-century Zeitgeist; get ready for it with An Anatomy of Thought. -Rob Lightner From Publishers Weekly How do we know? What do we think? How could a philosophical problem-'the mind-body problem,' say-induce a headache? What can evolutionary theory, molecular biology, the history of medicine and experimental psychology tell us about the features of human consciousness, and (once again) how do we know? Glynn, a physician and Cambridge University professor, meticulously attempts to answer these questions and more, setting forth the results of all sorts of research relevant to our brains-from 19th-century dissections to Oliver Sacks-like case studies, work with monkeys and supercomputers, and the enduring puzzles of philosophy, which he rightly saves for near the end. After explaining evolution by natural selection and 'clearing away much dross,' Glynn lays out the experiments and theories that have shown 'how nerve cells can carry information about the body, how they can interact' and how sense organs work; demonstrates the 'mixture of parallel and hierarchical organization' in our brains and 'the striking localization of function within it'; considers where neuroscience is likely to go; and admits that, among the many fields of exciting research just ahead, 'we can be least confident of progress toward a complete, scientific explanation of our sensations and thoughts and feelings.' Other recent explaining-the-brain books have sometimes advanced simplistic, or implausibly grand, claims about the nature and features of consciousness in general. Instead, Glynn offers a patient, informative, well-laid-out researcher's-eye view of what we have learned, how we figured it out and what we still don't know about neurons, senses, feelings, brains and minds. (Apr.) Copyright 2000 Reed Business Information, Inc. From Library Journal The nature of consciousness, which perennially troubles the minds of scientists and philosophers, is the subject of an ever-growing body of literature. Two of the latest entries approach the topic from different perspectives. Glynn, a professor of physiology and head of the Physiological Laboratory at Cambridge, offers a comprehensive summary of what we know about the brain-both its evolution and its mechanisms. Among the topics he covers are natural selection, molecular evolution, nerves and the nervous system, sensory perception, and the specific structures responsible for our intellect. Using the mechanisms involved in vision and speech as models, Glynn skillfully describes various neurological deficiencies that can lead to 'disordered seeing' and problems with the use of language. He carefully distinguishes what we know through experimental evidence from what we know through the observation of patients with neurological damage. He also describes some of the major theories that attempt to explain why these structures arose. While his book concentrates on the structures that make up the mind, Glynn is well aware that some physical events appear explicable only in terms of conscious mental events-a situation that conflicts with the laws of modern physics. Only briefly, however, does he consider the various approaches that have been taken to deal with the issues of mind/body and free will. In contrast, this is the primary focus of The Physics of Consciousness. After reviewing the fundamentals of classic physics, Walker (who has a Ph.D. in physics) summarizes elements of the new physics in which our knowledge of space, time, matter, and energy are all dependent on the moment of observation. Walker explores the meaning of consciousness as a characteristic of the observer. In this context both the observer and the act of measurement are critical. In essence, Walker leads his reader on a journey through his concept of a 'quantum mind,' which can both affect matter (including other minds) and can be affected by other distant matter/minds. To break up what would otherwise be an extremely dense text, Walker also relates the very touching story of the loss of his high-school sweetheart to leukemia. Indeed, it is his memory of their relationship that drives Walker to seek an understanding of ultimate reality. At times, he has a tendency to be dogmatic-as when he concludes, 'our consciousness, our mind, and the will of God are the same mind.' While An Anatomy of Thought is appropriate for most academic libraries, the Physics of Consciousness will be most accessible to readers with some knowledge of advanced physics. -Laurie Bartolini, Illinois State Lib., Springfield Copyright 2000 Reed Business Information, Inc. From Booklist The codiscoverers of natural selection-Charles Darwin and Alfred Wallace-disagreed over the possibility of finding an evolutionary explanation for the human mind. Glynn here argues Darwin's side of the debate, tracing an eons-long path of development starting from simple amino acids floating in primal seas and extending through the erect hominids in which the powers of a massive brain first manifest themselves. Patiently adducing evidence of an evolutionary origin for the underlying molecular machinery, Glynn dissects the nerve centers that make possible speech and hearing, sight, and reading. Pressing deeper, he lays bare the cortical foundations of personality. But those who deal with the mind must attend also to the arguments advanced by philosophers. And it is when he turns from dendrites to syllogisms (especially the vexing mind-body paradox) that Glynn's empirical reasoning fails him. In the end, he concedes his perplexity in trying to conceive of an evolutionary origin for human consciousness. This concession may set the shade of Alfred Wallace to chortling, but it will draw readers into an honest confrontation with a profound enigma. Bryce Christensen. (shrink)

One of the chief concerns of the young Descartes was with what he, and others, termed “physico-mathematics”. This signalled a questioning of the Scholastic Aristotelian view of the mixed mathematical sciences as subordinate to natural philosophy, non explanatory, and merely instrumental. Somehow, the mixed mathematical disciplines were now to become intimately related to natural philosophical issues of matter and cause. That is, they were to become more ’physicalised’, more closely intertwined with natural philosophising, regardless of which species of natural (...) philosophy one advocated. A curious, short-lived yet portentous epistemological conceit lay at the core of Descartes’ physico-mathematics—the belief that solid geometrical results in the mixed mathematical sciences literally offered windows into the realm of natural philosophical causation—that in such cases one could literally “see the causes”. Optics took pride of place within Descartes’ physico-mathematics project, because he believed it offered unique possibilities for the successful vision of causes. This paper traces Descartes’ early physico-mathematical program in optics, its origins, pitfalls and its successes, which were crucial in providing Descartes resources for his later work in systematic natural philosophy. It explores how Descartes exploited his discovery of the law of refraction of light—an achievement well within the bounds of traditional mixed mathematical optics—in order to derive—in the manner of physico-mathematics—causal knowledge about light, and indeed insight about the principles of a “dynamics” that would provide the laws of corpuscular motion and tendency to motion in his natural philosophical system. (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)

The historical antecedents of Frege's treatment of binocular vision in "The thought" were the physiological writings of Johannes Mueller, Hermann von Helmholtz, and Emil du Bois-Reymond. In their research on human vision, logic was assigned an unexpected role: it was to be the means by which knowledge of a world extended in three dimensions arises from stimuli that are at best two-dimensional. An examination of this literature yields a richer understanding of Frege's insistence that a proper epistemology requires us to (...) recognize the existence and importance of nonsensible sources of knowledge. (shrink)

This paper deals with Hobbes's theory of optical images, developed in his optical magnum opus, ‘A Minute or First Draught of the Optiques’, and published in abridged version in De homine. The paper suggests that Hobbes's theory of vision and images serves him to ground his philosophy of man on his philosophy of body. Furthermore, since this part of Hobbes's work on optics is the most thoroughly geometrical, it reveals a good deal about the role of mathematics in Hobbes's (...) philosophy. The paper points to some difficulties in the thesis of Shapin and Schaffer, who presented geometry as a ‘paradigm’ for Hobbes's natural philosophy. It will be argued here that Hobbes's application of geometry to optics was dictated by his metaphysical and epistemological principles, not by a blind belief in the power of geometry. Geometry supported causal explanation, and assisted reason in making sense of appearances by helping the philosopher understand the relationships between the world outside us and the images it produces in us. Finally the paper broadly suggests how Hobbes's theory of images may have triggered, by negative example, the flourishing of geometrical optics in Restoration England. (shrink)

As the word “optics” was understood from antiquity into and beyond the early modern period, it did not mean simply the physics and geometry of light, but meant the “theory of vision” and included what we should now call physiological and psychological aspects. From antiquity, these aspects were subject to geometrical analysis. Accordingly, the geometry of visual experience has long been an object of investigation. This chapter examines accounts of size and distance perception in antiquity (Euclid and Ptolemy) and the (...) Middle Ages (Ibn al-Haytham), before turning to "natural geometry" in Kepler and Descartes. It finds a purely mechanical realization of natural geometry in Descartes (primarily in his L'Homme, 1664), in which he conceives states of the visual system as varying in accordance with distance, much as his geometrical compasses vary their spatial relations in accordance with geometrical proportions. This reading challenges the notion that a two-dimensional sensation (without three-dimensional phenomenality) was universally accepted prior to the nineteenth century by positing a direct psychophysiological account of the experience of distance in Descartes. It thereby challenges the interpretations of Descartes on natural geometry of George Berkeley, Nancy Maull, Margaret Wilson, Erwin Panofsky, and Jonathan Crary. (shrink)

Comprehensive study of the social and medical history of dissection in classical antiquity and the parallel development of anatomical texts.

In this paper I consider the relation between Descartes' psychology of vision and the cognitive science approach to psychology (henceforth CS). In particular, I examine Descartes' the Optics (1637) in the light of David Marr's (1982) position in CS. My general claim is that CS can be seen as a rediscovery of Descartes' psychology of vision. In the first section, I point to a parallel between Descartes' epistemological revolution, which created the modem version of the problem of perception, and the (...) cognitive revolution. These fundamental revolutions in theoretical psychology were both inspired and legitimated by a revolution in mathematics. They took place in accordance with one of Marr's maxims: “To the desirable via the possible”. In the second section, I demonstrate that in the Optics, Descartes explains perception of metrical properties in a way that — on a detailed level — is in accordance with how Man argues that complex information processing systems have to be explained: both Descartes and Man emphasize the co-ordination of logical and physical analysis. In the third section, I claim that Descartes' arguments for a sharp distinction between mechanical transmission of sense data (sensation) and non-mechanical inferences on those sense data (thinking) are sound arguments seen from Man's position in CS. Descartes' arguments are based on his logical and physical analysis. Malebranche's radicalized version of Cartesian dualism turns Descartes' empirically-based assumption that mechanisms cannot realize inferences into a metaphysical assumption. In the final section, I argue that this metaphysical assumption contributes to an understanding of perception as a non-symbolic, non-inferential bottom-up process in mainstream monistic and mechanistic scientific psychology until the cognitive revolution. (shrink)

Originally published in 1991. Philoponus’ long commentary on Aristotle’s definition of light sets up the major concerns, both in optics and theory of light, that is discussed here. Light was of special interest in Neoplatonism because of its being something incorporeal in the world of natural bodies and therefore had a special role in the philosophical analysis of the interpenetration of bodies and also as a paradigm for the soul-body problem. The material investigated in this book contains much about the (...) physiology of vision as well as the propagation of light. Several chapters investigate the philosophical theory and its origins in ‘multiplication of species.’ These issues in the history of science philosophy are looked at further and an analysis is offered of the development of the distinction between Aristotle’s kinesis and energeia. The book covers a substantial amount of the philosophy of mathematical science from the point of view of Philoponus, drawing on more of his works relating to three dimensionality. (shrink)

This paper seeks to demonstrate that propositions 23–27 of the Euclidian Optics originated in the context of geometrical astronomy. These entries, which deal with the geometry of spheres and rays, present material that overlaps considerably with propositions 1–3 of Aristarchus of Samos’ On the Sizes and Distances of the Sun and the Moon. While all these theorems deal with material that could conceivably be native to celestial illumination, the proofs do not work for binocular vision. It therefore seems probable that (...) the proofs were borrowed from Aristarchus or, more likely, some common astronomical predecessor. As an extension of this observation, this paper argues that the Optics displays a far less unified purpose than has typically been assumed. Instead, it reflects a conglomerate of concerns, goals and dependencies, insofar as it presents multiple proofs that emerge from a set of geometrical concerns not directly related to vision as a physical phenomenon. These entries complicate the idea that the Optics is about explaining light, sight or false appearances in any straightforward sense. Instead, the text is oriented toward a somewhat more diffuse goal: simply to articulate the geometry of vision and rays. Optics as a discipline should should therefore be understood not as a purely mathematical explanation of vision, but as a target-field of explanation constituted by features and boundaries derived from extra-visual geometric concerns. (shrink)

Berkeley's "new theory of vision" and, In particular, His sensationalist solution to the problem of judging distance and magnitude were discussed by many eighteenth-Century authors who faced a variety of problem situations. More specifically, Berkeley's theory fed into the debate over whether the phenomena of vision were susceptible to mathematical analysis or were experientially determined. In this paper a variety of responses to berkeley are examined, Concluding with thomas reid's attempt to distinguish physical optics (which can be analyzed geometrically) from (...) the psychology of vision (in which experience plays a major role). (shrink)

Significantly, Berkeley, in his Essay Towards a New Theory of Vision, leveled a sustained attack on just this geometrical theory of distance perception. At first glance it may seem, as it did to Berkeley, that Descartes’ geometrical theory is produced by a simple error: namely, by the idea that a physiological optics provides an adequate description of the psychological processes of judging distances. In truth, this is the weakest of Berkeley’s objections to Descartes’ theory. Obviously we do not see the (...) angles and lines of convergence when we focus on a distant object, nor are we aware of having used any geometrical rules in judging distance. And Descartes never claimed this. (shrink)

Based on observations and interviews collected during a yearlong ethnography of two anatomy laboratory courses at a large Midwestern university, this article argues that students learn anatomy through the formation of an observational-embodied look. All of the visual texts and material objects of the lab—from atlas illustrations, to photographs, to 3D models, to human bodies—are involved in this look that takes the form of anatomical demonstration and dissection. The student of anatomy, then, brings together observation, visual evidence, haptic experience, and (...) anatomical-medical knowledge to identity as anatomy those objects on display. Through an interrogation of and reflection on the bodies of the course, the participants must learn to recognize and appreciate the descriptive and relational values of anatomical evidence, and in the process develop the habitus of anatomists. Drawing from the work of Maurice Merleau-Ponty, Pierre Bourdieu, and Herbert Dreyfus, the author seeks to both uncover how students learn anatomy as well as articulate a theory of embodied learning. (shrink)

The modern physiological optics introduces the notions related to the conditions of fusion of bi- nocular images by the concept of correspondence, due to Christiaan Huygens (1704), and by an experiment attri- buted to Christoph Scheiner (1619). The conceptualization of this experiment dates, in fact, back to Ptolemy (90- 168) and Ibn al-Haytham (d. af. 1040). The present paper surveys Ibn al-Haytham's knowledge about the mecha- nisms of binocular vision. The article subsequently explains why Ibn al-Haytham, a mathematician, but here (...) an experimenter, did not give the circular figure of the theoretical horopter, construction due to Gerhard Vieth (1818) and Johannes Müller (1826). But, on the other hand, it is clear that Ibn al-Haytham's experimental study puts in place the notion of corresponding points, the cases of homonymous and cross diplopia, and even prepares the discovery of Panum area. L'optique physiologique moderne introduit les notions relatives aux conditions de fusion des images binoculaires par le concept de correspondance, prêté à Christiaan Huygens (1704), et par une expérience attribuée à Christoph Scheiner (1619). L'article montre que la conceptualisation de l'expérience remonte en fait à Ptolémée (90-168) et à Ibn al-Haytham (m. ap. 1040), et précise les connaissances que ce dernier avait des mécanismes de la vision binoculaire. Il est ensuite expliqué pourquoi Ibn al-Haytham, mathématicien mais ici expérimentateur, ne donne pas la forme circulaire de l'horoptère théorique, dont la construction revient à Gerhard Vieth (1818) et Johannes Müller (1826). En revanche, l'étude expérimentale d'Ibn al-Haytham met en place la notion de points correspondants, les cas de diplopie homonyme et croisée et prépare même la découverte de l'aire fusionnelle de Panum. (shrink)

A number of ordinarily separate disciplines--e.g., physics, physiology, psychology--are here brought together in an effort to reconstitute optics as the complete science of human vision, thus replacing classical optics which dealt with vision only under perfect conditions. The emphasis is primarily scientific rather than philosophical.--R. G. S.

Thomas Reid claims to have learned of Idomenians, “an order of beings” in “sublunary regions” whose visual system is very much like ours except that they could detect only the direction of rays reaching their eyes, not the distance of origin. The properties of Idomenian vision are here examined in the light of the physiological optics of Reid’s time and of the scientific developments that have since augmented our knowledge of the discipline.

ArgumentTextual and material evidence suggests that early Byzantine architects, known asmechanikoi, were comprehensively educated in the mathematical sciences according to contemporary standards. This paper explores the significance of the astronomical and optical sciences for the working methods of the twomechanikoiof Hagia Sophia in Constantinople, Anthemios of Tralles and Isidoros of Miletus. It argues that one major concern in the sixth-century architectural design of the Great Church was the visual effect of its sacred interior, particularly the luminosity within. Anthemios and Isidoros (...) seem to have been thoroughly conversant with the ancient corpus of astronomical and optical writings and, as will be shown, implemented their theoretical knowledge in the design of Hagia Sophia. Specifically, the paper demonstrates that the orientation of the building's longitudinal axis coincides with the sunrise on the winter solstice according to ancient computations, implying that the orientation was intentionally calculated in order to secure an advantageous natural illumination of the interior. Light and visual effects served to reinforce the symbolic significance of the sacred space that furthermore provides evidence for optical considerations with respect to late antique concepts of light and vision. (shrink)

Morphological engineering is an emerging research area in synthetic biology. In 2008 “synthetic morphology” was proposed as a prospective approach to engineering self-constructing anatomies by Jamie A. Davies of the University of Edinburgh. Synthetic morphology can establish a new paradigm, according to Davies, insofar as “cells can be programmed to organize themselves into specific, designed arrangements, structures and tissues.” It is obvious that this new approach will extrapolate morphology into a new realm beyond the traditional logic of morphological research. However, (...) synthetic morphology is a highly idealized vision of morphology which derives its visionary ideas from morphological engineering and mathematical idealizations in order to understand the principles of molecular morphology. Thus, the question is, if this approach will help to understand morphogenesis better or if it will just enable biologists to engineer morphogenesis. The paper investigates the development of synthetic morphology and its relation to synthetic biology as well as its epistemic gains. (shrink)

Christine Buci-Glucksmann’s__ _The Madness of Vision_ is one of the most influential studies in phenomenological aesthetics of the baroque. Integrating the work of Merleau-Ponty with Lacanian psychoanalysis, Renaissance studies in optics, and twentieth-century mathematics, the author asserts the materiality of the body and world in her aesthetic theory. All vision is embodied vision, with the body and the emotions continually at play on the visual field. Thus vision, once considered a clear, uniform, and totalizing way of understanding the material (...) world, actually dazzles and distorts the perception of reality. In each of the nine essays that form _The Madness of Vision_ Buci-Glucksmann develops her theoretical argument via a study of a major painting, sculpture, or influential visual image—Arabic script, Bettini’s “The Eye of Cardinal Colonna,” Bernini’s _Saint Teresa_ and his 1661 fireworks display to celebrate the birth of the French dauphin, Caravaggio’s _Judith Beheading Holofernes,_ the Paris arcades, and Arnulf Rainer’s selfportrait, among others—and deftly crosses historical, national, and artistic boundaries to address Gracián’s_ El Criticón_; Monteverdi’s opera _Orfeo; _the poetry of Hafiz, John Donne, and Baudelaire; as well as baroque architecture and Anselm Kiefer’s Holocaust paintings. In doing so, Buci-Glucksmann makes the case for the pervasive influence of the baroque throughout history and the continuing importance of the baroque in contemporary arts. (shrink)

This article deals with physico-mathematical approaches to anatomy in post-Harveyan physiology. But rather than looking at questions of iatromechanics and animal locomotion, which often attracted this approach, I look at the problem of how blood returned to the heart – a part of the circulation today known as venous return but poorly researched in the early modern period. I follow the venous return mechanisms proposed by lesser-known authors in the mechanization of anatomy, such as Jean Pecquet (1622–1674) and Nicolaus Steno (...) (1638–1686), alongside the more famous Giovanni Alfonso Borelli (1608–1679). Their mechanisms differed only in small details. Yet, these minor differences highlight significant aspects of the mechanization of the life sciences in the seventeenth century. First, they relied more on observations than hitherto acknowledged, even if only indirectly. Second, their mechanisms drew more from the physico-mathematical disciplines than from the trending corpuscularian philosophies of their time. Finally, these mechanisms led to a more accurate understanding of the circulation that remains valid today, thus revealing their cognitive benefits. In short, through the single problem of how blood returned to the heart, this article portrays the increasing complexity of anatomy in the early modern period. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Vanities of the Eye: Vision in Early Modern European CultureDallas G. Denery IIStuart Clark. Vanities of the Eye: Vision in Early Modern European Culture. Oxford-New York: Oxford University Press, 2007. Pp. xi + 415. Cloth, $75.00.A popular and pervasive historical narrative links the Renaissance development of linear perspective with Europe’s transition from a pre-modern to an early modern society. Erwin Panofsky gave this narrative its definitive form early (...) in the twentieth century and William Ivins boiled it down to a simple idea that served as the title of his most famous book. According to Ivins, single-point perspective, the artistic technique championed by Alberti and perfected in the paintings of Masaccio and Piero della Francesca, allowed for “the rationalization of sight.” In other words, it provided a mathematically and geometrically grounded method for accurately representing the external world. It is a powerful and seductive claim, one that has shaped generations of scholarly work. It is also, Stuart Clark contends in this important new book, patently wrong. Far from exhibiting a renewed or reinvigorated confidence in the accuracy and reliability of vision, sixteenth- and seventeenth-century philosophers, artists, theologians, and doctors worried that sight was susceptible, perhaps permanently so, to all sorts of debilitating derangements, displacements, and delusions.Rather than relate a history of progress, Clark offers a history of exhaustion, failure, and, ultimately, of rejection. Early modern intellectuals inherited a comprehensive theory of vision and cognition from their medieval predecessors known as perspectivist optics. This theory sought to secure the accuracy of human sense perception through regularized causal processes that linked things in the world with our various cognitive faculties. While some fourteenth-century intellectuals, most notably Nicolas of Autrecourt and Nicole Oresme, recognized structural deficiencies in this theory, their critiques were mostly ignored or treated as anomalies. Over the course of the next two and a half centuries, Clark argues, the challenges to this theory multiplied until it collapsed under their weight (20).Clark’s argument is straightforward and, as his evidence mounts, thoroughly convincing. Throughout each of the eight engrossing chapters that form the core of the book, Clark outlines a different threat, a different set of challenges that pointed out problems with the assumption that vision is trustworthy. The range and depth of those challenges are truly amazing. Doctors worried that imbalances in our humoral system, and especially in the black bile that causes melancholy, could render our visual perceptions dubious at best (ch. 2). Theologians, wary of the dangers of witchcraft and eager to prosecute its practitioners, obsessed over the cognitive threats that devils and demons posed to good Christians (ch. 4), while Protestant reformers relegated the entire tradition of Catholic miracles to the counterfeit illusions of the antichrist (ch. 5). For their part, artists believed that perspective undermined vision, depending as it does on the assumption that what we see is always relative, dependent upon our point of view (ch. 3).Clark structures much of his argument around George Hakewill’s 1608 book, The vanitie of the eye, an exposition on the natural, artificial, and demonic sources that forever render visual knowledge suspect. He could just as well have organized it around the opening pages of Descartes’s Meditations, and in many ways Clark’s book serves as a superb rumination on the sources of Descartes’s skeptical arguments. Unlike Etienne Gilson and, more recently, Richard Popkin, both of whom have done so much to open up the scholastic and early modern sources of Descartes’s skeptical thought experiments, Clark does not limit himself to philosophical lineages. Rather, he considers sources of visual skepticism that developed across an entire culture—in natural philosophy, medicine, art, religion, and literature (especially in Shakespeare’s Macbeth). Not only does the sheer volume and variety of such [End Page 103] sources help to explain Descartes’s urgent desire to overturn everything he had learned and begin again from the foundations, but it also contextualizes the specific arguments he employs. None of Descartes’s skeptical arguments were new and most were well known in the Middle Ages. What had changed over the intervening centuries, Clark contends, was how these arguments drew from... (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Vanities of the Eye: Vision in Early Modern European CultureDallas G. Denery IIStuart Clark. Vanities of the Eye: Vision in Early Modern European Culture. Oxford-New York: Oxford University Press, 2007. Pp. xi + 415. Cloth, $75.00.A popular and pervasive historical narrative links the Renaissance development of linear perspective with Europe’s transition from a pre-modern to an early modern society. Erwin Panofsky gave this narrative its definitive form early (...) in the twentieth century and William Ivins boiled it down to a simple idea that served as the title of his most famous book. According to Ivins, single-point perspective, the artistic technique championed by Alberti and perfected in the paintings of Masaccio and Piero della Francesca, allowed for “the rationalization of sight.” In other words, it provided a mathematically and geometrically grounded method for accurately representing the external world. It is a powerful and seductive claim, one that has shaped generations of scholarly work. It is also, Stuart Clark contends in this important new book, patently wrong. Far from exhibiting a renewed or reinvigorated confidence in the accuracy and reliability of vision, sixteenth- and seventeenth-century philosophers, artists, theologians, and doctors worried that sight was susceptible, perhaps permanently so, to all sorts of debilitating derangements, displacements, and delusions.Rather than relate a history of progress, Clark offers a history of exhaustion, failure, and, ultimately, of rejection. Early modern intellectuals inherited a comprehensive theory of vision and cognition from their medieval predecessors known as perspectivist optics. This theory sought to secure the accuracy of human sense perception through regularized causal processes that linked things in the world with our various cognitive faculties. While some fourteenth-century intellectuals, most notably Nicolas of Autrecourt and Nicole Oresme, recognized structural deficiencies in this theory, their critiques were mostly ignored or treated as anomalies. Over the course of the next two and a half centuries, Clark argues, the challenges to this theory multiplied until it collapsed under their weight (20).Clark’s argument is straightforward and, as his evidence mounts, thoroughly convincing. Throughout each of the eight engrossing chapters that form the core of the book, Clark outlines a different threat, a different set of challenges that pointed out problems with the assumption that vision is trustworthy. The range and depth of those challenges are truly amazing. Doctors worried that imbalances in our humoral system, and especially in the black bile that causes melancholy, could render our visual perceptions dubious at best (ch. 2). Theologians, wary of the dangers of witchcraft and eager to prosecute its practitioners, obsessed over the cognitive threats that devils and demons posed to good Christians (ch. 4), while Protestant reformers relegated the entire tradition of Catholic miracles to the counterfeit illusions of the antichrist (ch. 5). For their part, artists believed that perspective undermined vision, depending as it does on the assumption that what we see is always relative, dependent upon our point of view (ch. 3).Clark structures much of his argument around George Hakewill’s 1608 book, The vanitie of the eye, an exposition on the natural, artificial, and demonic sources that forever render visual knowledge suspect. He could just as well have organized it around the opening pages of Descartes’s Meditations, and in many ways Clark’s book serves as a superb rumination on the sources of Descartes’s skeptical arguments. Unlike Etienne Gilson and, more recently, Richard Popkin, both of whom have done so much to open up the scholastic and early modern sources of Descartes’s skeptical thought experiments, Clark does not limit himself to philosophical lineages. Rather, he considers sources of visual skepticism that developed across an entire culture—in natural philosophy, medicine, art, religion, and literature (especially in Shakespeare’s Macbeth). Not only does the sheer volume and variety of such [End Page 103] sources help to explain Descartes’s urgent desire to overturn everything he had learned and begin again from the foundations, but it also contextualizes the specific arguments he employs. None of Descartes’s skeptical arguments were new and most were well known in the Middle Ages. What had changed over the intervening centuries, Clark contends, was how these arguments drew from... (shrink)

In his Elementorum Myologiae Specimen, Steno geometrizes "the new fabric of muscles" and their movement of contraction, so as to refute the main contemporary hypothesis about the functioning of the muscles. This physiological refutation relies on an abstract representation of the muscular fibre as a parallelepiped of flesh transversally linked to the tendons. Those two features have been comprehensively studied. But the method used by Steno, as well as the way he has chosen to present his physiological results, have so (...) far been neglected. Yet, Steno's work follows a true synthetic order, which he conceives as a tool to separate uncertain anatomical "elements" from the certain ones. We will show that the true understanding of this "more geometrico" order is the only way to avoid frequent misconceptions of the scientific aim pursued by Steno, which is neither to give a mathematical explanation of the functioning of the muscles, nor to reduce the muscles to some mathematical shapes. (shrink)

En 1928 la théorie des form constants par Klüver catégorisait les hallucinations visuelles en quatre grandes catégories. Alors que la notion de form constants venait à s’appliquer virtuellement à toutes les figures entoptiques, comme l’avait prévu son auteur, dont les photismes synesthésiques, Cytowic a décrit et Carol Steen représenté ce que voient réellement des synesthètes visuels. L’une des caractéristiques d’œuvres de peintres synesthètes serait justement la présence de ces formes classées par Klüver. L’anthropologie avec la thèse de l’externalisation a montré (...) que certaines cultures ont repris les form constants perçues dans le premier stade de l’intoxication pour en faire les patterns de leur art. Les modèles physiologico-mathématiques permettent de localiser en V1 l’origine de production des photismes et d’expliquer leur morphogénèse. Mais une explication des circuits neuraux empruntés pour passer des différents types de déclencheur sensoriel à l’apparition de photismes synesthésiques reste aujourd’hui au stade de l’hypothèse. La synesthésie est l’objet de recherches alliant les sciences les plus contemporaines dont la génomique. Il est possible que les études sur la synesthésie transforment son statut de phénomène marginal en un élément essentiel dans la compréhension du système physiologique sous-jacent à l’esprit humain. In 1928, Klüver’s theory of form constants placed visual hallucinations into four broad categories. Whereas, as predicted by its author, the notion of form constants was virtually applicable to all entoptic figures, including synesthetic photisms, the very notion of entoptics was definitively extended. Cytowic has described and Carol Steen has represented what visual synesthetes actually see. The presence of these forms, as they have been classified by Klüver, is precisely one of the characteristics of the works of synesthetic painters. With the thesis of externalization, the field of Anthropology has shown that some cultures have adopted the constant forms perceived in the first stage of intoxication as patterns for their art. Physiological-mathematical models allow us to locate the origin of photism production in V1, and to explain these photisms’ morphogenesis. But, even today, an explanation of the neural pathways used to pass from different types of sensory triggers to the appearance of synesthetic photisms remains at the hypothesis stage. Synesthesia is a research topic that combines some of the most contemporary sciences, including genomics. Studies on synesthesia may just transform its status as that of a marginal phenomenon into that of an essential element in understanding the physiological system underlying the human mind. (shrink)

Nicholas of Cusa’s deployment of an omnivoyant image in the De visione Dei has been said to deconstruct Leon Battista Alberti’s mathematical determination of space in single-point linear perspective. While there has been some debate over whether the omnivoyant functions like a medieval icon or instead like a Renaissance painting, what has been neglected is a more careful analysis of what underlies the very structure of omnivoyance, namely the milieu from which its contradictions and paradoxes emerge. In this article, I (...) will show how thinking the milieu of vision, implicit in Cusa’s optics, lets us overcome any overly simple binaries in these debates and deepen our understanding of the meaning of omnivoyance. (shrink)

My title, of course, is an exaggeration. The world no more became mathematical in the seventeenth century than it became ironic in the nineteenth. Either it was mathematical all along, and seventeenth-century philosophers discovered it was, or, if it wasn’t, it could not have been made so by a few books. What became mathematical was physics, and whether that has any bearing on the furniture of the universe is one topic of this paper. Garber says, and I agree, that for (...) Descartes bodies are the things of geometry made real ( Ref). That is a claim about the world: what God created, and what we know in physics, is nothing other than res extensa and its modes. Others, including Marion, hold that in modern science, here represented at its origins by Descartes, representation displaces beings: the knower no longer confronts Being or beings but rather a system of signs, a “code” as Marion calls it, to which the knower stands in the relation of subject to object. The Meditations, or perhaps even the Regulæ, are the first step toward the transcendental idealism of Kant. Most of this paper will be devoted to a more concrete question. Physics in the seventeenth century increasingly became a matter of applying mathematical knowledge to the solution of physical problems. The “mixed sciences” of astronomy, optics, and music, sciences then distinct from physics, became models of understanding for all of natural philosophy. My interest here is in one aspect of that development: how particular physical situations are transformed into mathematical. I will look at the work of Descartes and Isaac Beeckman, contrasting their visions of “physico-mathematics”. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:A Humanist History of Mathematics?Regiomontanus's Padua Oration in ContextJames Steven ByrneIn the spring of 1464, the German astronomer, astrologer, and mathematician Johannes Müller (1436–76), known as Regiomontanus (a Latinization of the name of his hometown, Königsberg in Franconia), offered a course of lectures on the Arabic astronomer al-Farghani at the University of Padua. The only one of these to survive is his inaugural oration on the history and (...) utility of the mathematical arts.1 Regiomontanus tells his audience that the purpose of the oration is torelate first the origin of our arts, and among which nations they first began to be cultivated, in what way they were at last translated from various foreign tongues into Latin, which of our ancestors were famed in these disciplines, and to whom in our lifetimes recognition should be granted.2To this end, he offers a history of the quadrivial arts (arithmetic, geometry, music, and astronomy) and other important mathematical disciplines from [End Page 41] antiquity to his own time, praises their utility, and exhorts his audience to revive the languishing study of mathematics at Padua. Astrology, a discipline with which Regiomontanus himself was closely associated, is singled out for particular praise.Traditionally, Regiomontanus's Padua oration has been seen through the lens of its rather obvious humanism. In particular, the Padua oration has come to be understood as the rhetorical embodiment of the fifteenth-and-sixteenth-century revival of ancient (Greek) mathematics. Just as this revival is inextricable from the rise of humanism, so Regiomontanus has come to be seen as an exemplar of humanist mathematics.3 It is the aim of this paper to examine the Padua oration in the context both of contemporary humanist rhetoric and of Regiomontanus's own intellectual background in order to argue that, while the oration is stylistically consistent with humanist norms, the vision of mathematics presented in it is also deeply grounded in the university mathematical curriculum and in Regiomontanus's own reading of mathematical texts.Regiomontanus was educated primarily at the University of Vienna (he was also briefly at the University of Leipzig), where he enrolled in 1450, completed his baccalaureate in 1452 and became a master in 1457.4 He remained at Vienna until 1461, when the death of his friend and teacher Georg Peurbach prompted him to travel to Italy with his patron, Cardinal Bessarion.5 In Regiomontanus's day Vienna was probably the most important of the German universities, rivaled only by Prague, whose prestige had declined after it was stripped of its theology faculty in the aftermath of the Hussite Wars.6 The curriculum at the University of Vienna was modeled [End Page 42] after that of Paris, and Parisian scholars played a major role both in its founding in 1365 and in its re-establishment (this time with a theology faculty) in 1384.7Most importantly for the purposes of this paper, the Viennese mathematical curriculum of Regiomontanus's day included all of the traditional authorities taught at Paris in the fourteenth century. For arithmetic and algebra, various "algorisms" (prose or poetry instructions for carrying out arithmetical operations that often also included a small amount of number theory) were the basic texts, supplemented in the fourteenth century by the Quadripartitum numerorum of Jean de Murs. Jordanus de Nemorare's De numeris datis and al-Khwarizmi's Algebra were common sources for those engaged in more advanced studies (i.e., they were not normally the subject of ordinary lectures, but were readily available to interested students, and would perhaps have been the subject of occasional extraordinary lectures). Euclid's Elements, supplemented by the commentaries of Pappus and Campanus, was the central text for geometry, and a number of medieval texts on practical and speculative geometry were in circulation as well. For astronomy, the Sphere of Sacrobosco and the Theorica planetarum were the most commonly used teaching texts, sometimes supplemented by al-Farghani's Elements of Astronomy (the subject of Regiomontanus's Padua lectures). Advanced students could read numerous more specific treatises by Arabic and Latin authors. For optics, the Perspectiva communis of John Peckham was the most common basic text, with texts... (shrink)

Christine Buci-Glucksmann’s The Madness of Vision is one of the most influential studies in phenomenological aesthetics of the baroque. Integrating the work of Merleau-Ponty with Lacanian psychoanalysis, Renaissance studies in optics, and twentieth-century mathematics, the author asserts the materiality of the body and world in her aesthetic theory. All vision is embodied vision, with the body and the emotions continually at play on the visual field. Thus vision, once considered a clear, uniform, and totalizing way of understanding the material (...) world, actually dazzles and distorts the perception of reality. In each of the nine essays that form The Madness of Vision Buci-Glucksmann develops her theoretical argument via a study of a major painting, sculpture, or influential visual image—Arabic script, Bettini’s “The Eye of Cardinal Colonna,” Bernini’s Saint Teresa and his 1661 fireworks display to celebrate the birth of the French dauphin, Caravaggio’s Judith Beheading Holofernes, the Paris arcades, and Arnulf Rainer’s selfportrait, among others—and deftly crosses historical, national, and artistic boundaries to address Gracián’s El Criticón; Monteverdi’s opera Orfeo; the poetry of Hafiz, John Donne, and Baudelaire; as well as baroque architecture and Anselm Kiefer’s Holocaust paintings. In doing so, Buci-Glucksmann makes the case for the pervasive influence of the baroque throughout history and the continuing importance of the baroque in contemporary arts. (shrink)

During the second half of the 19th century, in the field of physiological optics, there was a strong controversy between Hermann von Helmholtz and Ewald Hering. This controversy has been usually characterized as “empiricism” vs. “nativism”. In the field of physiology of visual perception, several subjects demanded attention, among them, color vision. Helmholtz and Hering suggested different theories for the physiological correlate of color sensation and different color spaces to give an account of the relationships between colors. In this article, (...) I will argue that the controversy between the two authors could be understood as differences between styles of reasoning, and these different styles express different presuppositions. More specifically, I want to suggest that the disagreements could be linked to the discussions on how vital phenomena should be studied. (shrink)

This chapter examines a question at the intersection of the mind-body problem and the analysis of mental representation: the question of the direction of constraint between psychological fact and theory and neurophysiological or physical fact and theory. Does physiology constrain psychology? Are physiological facts more basic than psychological facts? Or do psychological theories, including representational analyses, guide and constrain physiology? Despite the antireductionist bent of functionalist positions, it has generally been assumed that physics or physiology are more basic than, and (...) hence contraining on, psychological fact and theory. Section 1 sketches the intuitions that would lead one to adopt such a view. The chapter then examines whether one-sided constraint has been and should be found in practice. It argues that philosophical analysis of psychological science shows that rigorous functional analyses can be carried out in advance of physiological knowledge. Indeed, in the investigation of sensory perception, ascription of psychological function leads the way in the individuation and investigation of neurophysiology. We shall look at several cases in visual perception (binocular single vision, stereopsis, and color vision), in which psychological results have provided a basis for physiological research. It is tempting to think that the psychological functions that enable physiological investigation would be Wrightian teleofunctions. It is, thus, natural to suppose that psychologists and neurophysiologists have proceeded with a conception of the purpose of a given neural structure, and have viewed neural anatomy and neural activity as the substrate for or instantiation of various properly psychological functions. For example, neuroscientists surely understand that the eye and visual system are for seeing, rather than for detecting an electric discharge in the vicinity of the retina (which sighted humans can do, via the subjective light produced by such discharges), and they guide their investigations of the eye, visual cortex, and intervening pathways accordingly. As a result, they will view rods and cones in the eye as photoreceptors, even though these structures will produce "output" (will respond with hyperpolarization) to other forms of energy. At the same time, there may be cases in which the functions that have guided research are in fact precisely determined input-output functions, whose teleofunctional status is absent or misdescribed. I will argue that in the case of trichromatic color matches, the psychological function involved is an input-output function, and that this result has implications for the description of color vision as a psychological capacity. (shrink)

This article focuses on some theoretical developments prompted by the use and construction of telescopes in the first half of the seventeenth century. It argues that today's notion of "scientific instrument" cannot be used to categorize these optical devices or explain their impact on natural philosophy. The article analyzes in historical terms the construction of conceptual references for the telescope as an instrument of a new kind, which possessed capabilities and working principles unlike those of traditional "mathematical instruments." It shows (...) that through the 1650s, in both rhetorical and explanatory terms, first-rank telescope makers, theoreticians, and astronomers found it useful to equate the telescope with the eye, suggesting that the data the telescope produced was as reliable as that obtained in naked-eye vision. Kepler's and Descartes' theory of the telescope will be shown to dovetail uncannily with this understanding of the telescope. (shrink)

"A person is not explainable in molecular, field-theoretical, or physiological terms alone." With that declaration, Nobel laureate Gerald M. Edelman goes straight to the heart of Nature's Imagination, a vibrant and important collection of essays by some of the world's foremost scientists. Ever since the Enlightenment, the authors write, science has pursued reductionism: the idea that the whole can be understood by examining and explaining each of its parts. But as this book shows, scientists in every discipline are reaching for (...) a new paradigm that accounts for the whole--from the individual person to the universe itself. Nature's Imagination gathers together the work of thirteen leading mathematicians, astronomers, neuroscientists, and philosophers, as they discuss the revolution sweeping the sciences. Here Roger Penrose, Oliver Sacks, John Barrow, Gregory Chaitin, Maragret Boden, and others explore how and why classic reductionism is falling by the wayside in their own fields. As Freeman Dyson writes in the introduction, science is an art form, not a philosophical method, and it is always in search of new tools. Reductionism has done its work, and scientists are in search of another. Roger Penrose offers a fascinating account of irreducibility in mathematics, starting with the example of an impossible triangle--a drawing of a triangular object twisted so that could not exist in three dimensions. He breaks the triangle into three parts, showing that each corner is physically possible; only in combination is the triangle impossible. Both Penrose and mathematician Gregory Chaitin explore Godel's incompleteness theorem--as does John Barrow, who explains that Chaitin's proof of the theorem shows that, if we ever arrive at a Theory of Everything, there may be a still deeper and simpler unifying theory beyond that. Other contributors discuss the changing thinking in neuroscience, and the limitations of a mechanical view of the mind: as Oliver Sacks writes, "if we are to have a model or theory of mind as this actually occurs in living creatures in the world, it may have to be radically different from anything like a computational one." In addition, this volume includes staunch defenders of the classic scientific approach, such as Peter Atkins ("The omnicompetence of science, and in particular the simplicity its reductionist insight reveals, should be accepted as a working hypothesis until, if ever, it is proved inadequate"). The advance of science has been so startlingly swift in the last century that it has begun to approach limits never dreamed of before. This remarkable volume captures the latest thinking on where we must turn if we are to truly understand oursevles and the universe we live in. (shrink)

Insect and crustacean lineages diverged over 500 Myr ago, and there are continuing uncertaintles about whether they evolved from a common arthropod ancestor or, alternatively, they evolved independently from annelid worms. Despite the diversity of their limbs and lifestyles, the nervous systems of insects and crustaeeans share many common features both in development and in function. Cellular and molecular embryology techniques reveal good evidence for homologies in the developing segmental ganglia. In the visual system, this seemingly common programme of insect (...) and crustacean CNS development culminates in common adult neural function. Comparisons of the cellular anatomy and physiology of animals as diverse as flies and crayfishes indicate that the neural circuits in the lamina of their optic lobe have been inherited largely unchanged from a common ancestor with good compound eyes. (shrink)

Galen's æuvre presents a remarkably varied body of texts–varied in subject matter, style, and didactic purpose. Logical tracts sit alongside tomes of drug–lore; handbooks of dietetics alongside anatomical investigations; treatises of physiology alongside ethical opuscula. These differences in type have received some, though as yet insufficient, scholarly attention. Mario Vegetti demonstrated the coexistence of two ‘profili’ or images of the art of medicine: Galen presents the art as an Aristotelian deductive science, on the one hand, and as a technician's craft, (...) on the other. The former image, offering an ambitious elevation of the doctor's cultural status, has medicine as a philosophical episteme analogous to the mathematical sciences, exercised above all to provide causal accounts and logical demonstrations, and centred on the knowledge of anatomy. The second image is that of the clinician, concerned with the body in its pathological manifestations and using as its prime model the ‘pre-anatomical’ theory of the humours. And the content of the treatises shifts in relation to this dual image: ‘profilo alto’ and ‘profilo basso’ are reflected in different types of work. Polemical writings such as the Protrepticus, as well as the great treatises of anatomy and physiology, De usu partium and De naturalibus facultatibus, present medicine in the former light, while works like De temperamentis or Quod animi mores base themselves on humoral pathology and accord with the earlier, artisan-like image. (shrink)

Noam Chomsky and Frances Egan argue that David Marr’s computational theory of vision is not intentional, claiming that the formal scientific theory does not include description of visual content. They also argue that the theory is internalist in the sense of not describing things physically external to the perceiver. They argue that these claims hold for computational theories of vision in general. Beyond theories of vision, they argue that representational content does not figure as a topic within formal computational theories (...) in cognitive science. I demonstrate that Chomsky’s and Egan’s claims about Marr’s theory are false. Marr’s computational theory contains a mathematical theory of visual content, based on empirical psychophysical evidence. It also contains mathematical descriptions of distal physical surfaces and objects, and of their optic projection to the perceiver. Much computational research on vision contains these types of intentional and externalist components within the formal, mathematical, theories. Chomsky’s and Egan’s claims demonstrate inadequate study and understanding of Marr’s work and other research in this area. Computational theories of vision, by containing empirically based mathematical theories of visual content, to this extent present naturalizations of semantics. (shrink)

The cerebral cortex is a rich and diverse structure that is the basis of intelligent behavior. One of the deepest mysteries of the function of cortex is that neural processing times are only about one hundred times as fast as the fastest response times for complex behavior. At the very least, this would seem to indicate that the cortex does massive amounts of parallel computation.This paper explores the hypothesis that an important part of the cortex can be modeled as a (...) connectionist computer that is especially suited for parallel problem solving. The connectionist computer uses a special representation, termed value unit encoding, that represents small subsets of parameters in a way that allows parallel access to many different parameter values. This computer can be thought of as computing hierarchies of sensorimotor invariants. The neural substrate can be interpreted as a commitment to data structures and algorithms that compute invariants fast enough to explain the behavioral response times. A detailed consideration of this model has several implications for the underlying anatomy and physiology. (shrink)

The influence of light on the lives of living organisms is all-pervasive, affecting movement, vision, behavior, and physiological activity. This book is a biophysically grounded comparative survey of how animals detect light and perceive their surroundings. Included are discussions of photoreceptors, light emitters, and eyes. The book focuses in particular on the kinds of optical systems that have evolved, beginning with unicellular organisms that detect and respond to light through to more advanced and complex designs for imaging. The relevance of (...) these studies extends beyond biology, since these findings can be used to help develop photoreceptor energy conversion and information systems, and optical imaging devices with a wide range of everyday applications. The book will appeal to biophysicists, photobiologists, bioengineers, neuroscientists, and all researchers working in the area of vision and visual optics. (shrink)

The cerebral cortex is a rich and diverse structure that is the basis of intelligent behavior. One of the deepest mysteries of the function of cortex is that neural processing times are only about one hundred times as fast as the fastest response times for complex behavior. At the very least, this would seem to indicate that the cortex does massive amounts of parallel computation.This paper explores the hypothesis that an important part of the cortex can be modeled as a (...) connectionist computer that is especially suited for parallel problem solving. The connectionist computer uses a special representation, termed value unit encoding, that represents small subsets of parameters in a way that allows parallel access to many different parameter values. This computer can be thought of as computing hierarchies of sensorimotor invariants. The neural substrate can be interpreted as a commitment to data structures and algorithms that compute invariants fast enough to explain the behavioral response times. A detailed consideration of this model has several implications for the underlying anatomy and physiology. (shrink)

This is a systematic and critical account of Berkeley’s philosophy of science. Brook’s intention is to evaluate Berkeley’s analysis of significant scientific concepts, his general theories in optics, physics, and mathematics, and finally Berkeley’s own interpretation and criticism of Newton’s principles. That Berkeley’s writings are pervaded with ambiguities, inconsistencies, and misinterpretations of Newton seems to be the conclusion that Brook reaches, although he does distinguish in the writings the areas in which he feels Berkeley is on target. Berkeley conceived (...) the purpose of science to be the practical mastery of nature, and his philosophy is indicative of a phase in the evolution of a "new" science that had its roots as far back as Galileo who envisioned a universe that could be read off in terms of mathematical relationships. This view entailed the overthrow of traditional physics and its concern with substantial forms and qualitative changes. As Brook points out, the object of physics for Berkeley is a phenomenal order that can at best display only uniformities, efficient causality belongs to the realm of metaphysics. Brook does not go into the metaphysical or historical foundations of Berkeley’s philosophy of science, but his first chapter on the theory of signification presents sufficient background for the more detailed and complex chapters that deal with his theory of vision, philosophy of physics and mathematics. This is not an easy book to read, and the chapter on Berkeley’s mathematics may prove to be especially difficult to those who lack an orientation to this field. Yet Brooks could hardly do better than he does considering the obscurities and obfuscatory trappings that are to be found in the primary sources from which he is working. A good bibliography is included that should serve to facilitate a reading of this book. Brook’s study is the only work to date that takes into account Berkeley’s scientific works as a whole and not just some aspects.—K.R.M. (shrink)

This chapter contains section titled: Basic Facts about Dolphins Adaptations to Living in the Water The Dolphin Brain The Human Brain The Human Brain: Summary The Dolphin Brain Compared to the Human Brain The Dolphin Brain: Summary.

Modern color science finds its birth in the middle of the nineteenth century. Among the chief architects of the new color theory, the name of the polymath Hermann von Helmholtz stands out. A keen experimenter and profound expert of the latest developments of the fields of physiological optics, psychophysics, and geometry, he exploited his transdisciplinary knowledge to define the first non-Euclidean line element in color space, i.e., a three-dimensional mathematical model used to describe color differences in terms of color distances. (...) Considered as the first step toward a metrically significant model of color space, his work inaugurated researches on higher color metrics, which describes how distance in the color space translates into perceptual difference. This paper focuses on the development of Helmholtz’s mathematical derivation of the line element. Starting from the first experimental evidence which opened the door to his reflections about the geometry of color space, it will be highlighted the pivotal role played by the studies conducted by his assistants in Berlin, which provided precious material for the elaboration of the final model proposed by Helmholtz in three papers published between 1891 and 1892. Although fallen into oblivion for about three decades, Helmholtz’s masterful work was rediscovered by Schrödinger and, since the 1920s, it has provided the basis for all subsequent studies on the geometry of color spaces up to the present time. (shrink)

In this paper I challenge the widely held view which associates Hume’s philosophy with mechanical philosophies of nature and particularly with Newton. This view presents Hume’s account of the human mind as passive receiver of impressions which bring into motion, from the outside, a mental machinery whose functioning is described in terms of mechanical causal principles. Instead, I propose an interpretation which suggests that for Hume the human mind is composed of faculties that can be characterized by their active contribution (...) which frequently results in qualitative change. This anatomy of the mind is explored from a physiological perspective focused on the normal functioning and interaction of the mind’s various organs. While pursuing this enterprise, I suggest that Hume’s outlook is closer to eighteenth-century “philosophical chemistry” and vitalistic physiology than to the heritage of mechanical philosophies. (shrink)

The physiological blind spot corresponds to the optic disc where the retina contains no light-detecting photoreceptor cells. Our perception seemingly fills in this gap in input. Here we suggest that rather than an active process, such perceptual filling-in could instead be a consequence of the integration of visual inputs at higher stages of processing discounting the local absence of retinal input. Using functional brain imaging, we resolved the retinotopic representation of the physiological blind spot in early human visual cortex and (...) measured responses while participants perceived filling-in. Responses in early visual areas simply reflected the absence of visual input. In contrast, higher extrastriate regions responded more to stimuli in the eye containing the blind spot than the fellow eye. However, this signature was independent of filling-in. We argue that these findings agree with philosophical accounts that posit that the concept of filling-in of absent retinal input is unnecessary. (shrink)

In Amerindian ontologies, hallucinations or visions, rather than being dismissed as delusions or symbolic constructs, are recognized as means of perceptual access to physical reality. Lowland South American shamans claim to be able to diagnose and treat infectious diseases, and to assess the status of wildlife resources through interactions with pathogenic agents perceived in visions. This essay examines some perceptual capabilities that shamans might be employing to explore their physical reality. The structure of the eye affords a form of microscopy (...) of retinal structures and of objects flowing within them, including cells and microbial agents during systemic infection. Lowland South American shamanic practices involve optical and physiological conditions that optimize entoptic microscopy. Images of those visions display the characteristic features of shadow formation, confirming their microscopic origin. This phenomenological access to the microscopic world and similarities with the panorama depicted by current microbiology indicate the commensurability of these forms of knowledge. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:HUME'S IDEAS In the eighteenth century, there was widespread acceptance of a physiological basis for cognition. Some writers even argued for a rather detailed correlation between awareness and physiological changes, suggesting that (a) the former could be adequately explained in terms of the latter or, in some few instances, (b) that the former are the latter. David Hartley may come to mind as fitting one or the other of (...) these alternatives, but Robert Hooke had earlier argued for ideas as brain impressions, as of course did Descartes in his early scientific treatises. There was also one medical doctor in the eighteenth century, Dr. Astruc, who seems (on the basis of what Chambers reports) to have attempted a very specific correlation between specific forms of awareness and specific states and changes in physiology. There were also writers in this century who warned against the dangers of using physical-object vocabulary when talking about the mind and acts of awareness. Berkeley is one such writer,- Thomas Reid at the end of the century traced, to the use of this vocabulary, what he took to be the indirect realism of the way of ideas. Hume is writing in both these traditions: the tradition of using physical language for characterizing mental operations and the tradition of physiological explanations and correlations. The phrase used by Alexander Pope and Hume, 'the anatomy of the mind', seems to be a mixed metaphor, but it is a phrase which I take as an indication that Hume is doing what we would call 'cognitive psychology'. Another phrase used by Hume (this time in the Enquiry), 'mental geography', may capture his enterprise better: 'geography' still sounds physical, but it is modified by 'mental'. Hume is engaged in mental mapping. I want to take a look at the use of the term 'idea' in Hume's writing (mainly in the Treatise) in order to see 2. whether Hume's text enables us to say anything about the nature of his ideas, to discover what role they play in his mental geography. As far as I can determine, there are three possible candidates for the nature of ideas in Hume: images, brain impressions, and cognitive contents. The first of these is, I think, the standard reading of Hume's ideas. Professor Anderson has presented strong argument and evidence to support the second. I will be suggesting that the third is the best candidate, given the full range of the text of the Treatise. Of course, the correct answer 4 may be all three of these. The Treatise opens by dividing all perceptions of the human mind into two kinds. Impressions and ideas differ in the degree of force and liveliness with which they strike upon the mind. Even though the language of 'force' and 'liveliness' may be borrowed from physical talk, it is the mind, not the brain, on which perceptions strike. The examples of impressions are sensations, passions, and emotions. Ideas are said to be the faint images of these impressions in thinking and reasoning. The term 'image' throughout the eighteenth century never receives any clear explication. Its inheritance from optical treatises always hangs about it. We should look to the examples cited by Hume, in order to see whether we can construct a meaning for that term when used in these psychological contexts. Let us look first at his very first example of 'ideas': all the perceptions excited by the present discourse. (Tl) He explicitly excludes from these perceptions those which arise from the sight and touch, as well as the immediate pleasure or uneasiness his discourse may excite in us. The perceptions which are thus excluded are sensations and emotions, the impressions he has just distinguished. The only candidate left for ideas would seem to be what this discourse says, our thoughts about it, my understanding of what it says. The distinction is not one Hume thinks is difficult to follow: Every one of himself will readily perceive the difference betwixt feeling and thinking. (Tl-2) Last week I was sad, today I recall that feeling of sadness/ the difference between being sad and remembering that I was sad. Hume gives a different example: the perceptions formed when... (shrink)