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.

Pioneering molecular work on chelicerate visual system development in the horseshoe crab Limulus polyphemus surprised with the possibility that this process may not depend on the deeply conserved retinal determination function of Pax6 transcription factors. Genomic, transcriptomic, and developmental studies in spiders now reveal that the arthropod Pax6 homologs eyeless and twin of eyeless act as ancestral determinants of the ocular head segment in chelicerates, which clarifies deep gene regulatory and structural homologies and recommends more unified terminologies in the (...) comparison of arthropod visual systems. Following this phylotypic stage, chelicerate visual system development differs fundamentally from other arthropods during the compartmentalization of the ocular segment in that eye and optic neuropil primordia originate independently from each other. Comparative analyses of this phase identified further gene regulatory homologies but also major differences, most notably the possibly compensatory replacement of Pax6 by Pax2 in lateral eye specification. Also see the video abstract here: https://youtu.be/Hdfr3z5kEXU. (shrink)

Molyneux’s question famously asks about whether a newly sighted subject might immediately recognize, by sight alone, shapes that were already familiar to her from a tactile point of view. This paper addresses three crucial points concerning this puzzle. First, the presence of two different questions: the classic one concerning visual recognition and another one concerning vision-for-action. Second, the explicit distinction, reported in the literature, between ocular and cortical blindness. Third, the importance of making reference to our best neuroscientific account (...) on vision, ‘the two visual systems model’, in order to better address Molyneux’s problem. Then, by offering a new, deeper analysis of the relation between, and, this paper suggests that the subjects of Molyneux’s two different questions show the same visual impairment as brain-damaged subjects with different lesions of the visual cortex. In particular, the subject of the first question shows the same impairment in visual recognition as a visual agnosic subject, while the subject of the second question shows the same visual impairment in visuomotor processing as an optic ataxic subject. These impairments still hold even if ocular processing is restored. Therefore, I suggest the following. For the first classic question, the required experimental setting cannot be properly reached. By contrast, concerning the second question, based on the interpretation we select, either the answer is negative, or, as with the first question, the experimental setting cannot be properly reached. This proposal constitutes, with the other approaches offered in the literature, a further attempt to tackle the enormous complexity of Molyneux’s puzzle. (shrink)

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

Ocular gene transfer clinical trials are raising hopes for blindness treatments and attracting media attention. News media provide an accessible health information source for patients and the public, but are often criticized for overemphasizing benefits and underplaying risks of novel biomedical interventions. Overly optimistic portrayals of unproven interventions may influence public and patient expectations; the latter may cause patients to downplay risks and over-emphasize benefits, with implications for informed consent for clinical trials. We analyze the news media communications landscape (...) about ocular gene transfer and make recommendations for improving communications between clinicians and potential trial participants in light of media coverage. (shrink)

_ Source: _Volume 29, Issue 1, pp 86 - 102 The aim of this paper is to give an overview of the place that Hobbes assigns to optics in the context of his classification of sciences and disciplinary boundaries. To do this, I will begin with an account of Hobbes’s conception of philosophy or science, and particularly his distinction between true and hypothetical knowledge. I will also show that in his demarcation between mathematics or geometry and natural philosophy Hobbes (...) was influenced by Galileo’s _Dialogue_. I then analyse the consequences of this distinction for optics, and conclude by clarifying its status among the scientific disciplines. (shrink)

The somewhat deflating conclusion of Simon A. Gilson's meticulous examination of Dante's incorporation of the science of optics and theories of light is that the poet was considerably less well read than we have been giving him credit for.Gilson's book is divided into two parts: the first, dealing with the science of optics, contains four chapters; the second, dealing with theories of light, contains three. Each of these parts is devoted to debunking a tendency in Dante scholarship to (...) attribute to a particular scientific or philosophical movement a marked influence on his work. In the first part Gilson maintains that Dante's use of the science of optics does not—as others, most forcefully and influentially Alessandro Parronchi, have argued—rely specifically on knowledge of the authors of the perspectivae—detailed treatises on optics that placed the influence of light rays at the origin of terrestrial phenomena—that is, on such thinkers as Alhazen, Roger Bacon, and Robert Grosseteste. Rather, Gilson contends that Dante could easily have come by the requisite expertise concerning this science through contact with the more popular and widely known doctrines of such Arab interpreters of Aristotle as Avicenna and Averroës and the commentaries of Albert the Great and Thomas Aquinas. He demonstrates the plausibility of this contention by way of a comparative analysis of the doctrines of the perspectivists and the Arab interpreters. This analysis is followed by a chapter devoted to optics and vision in Dante's earlier poetry.The two following chapters cover, respectively, topics such as blinding, optical illusions, and visual error in Dante's Commedia and the themes of reflection, mirrors, and meteorological optics, also in the Commedia, a work that Gilson specifies as having nevertheless gone beyond the more limited sources of the earlier poetry. In the third chapter Gilson's analysis achieves a welcome degree of insight into the poet's originality: here Gilson shows how Dante incorporates the scientific knowledge of his day in order to establish a set of limits that circumscribe human action in the physical world but that must be overcome in the course of the pilgrim's journey through his imaginative world. Such moments provide a refreshing alternative to an otherwise rather positivistic view of scientific knowledge as a compendium of facts and sources one either has or has not read. One cannot help but think that researchers in the field of the history of science might be most interested in the imaginative contributions of a specifically poetic knowledge, especially in an age in which the distinction between “hard” and “soft” science was not accorded the kind of unquestioned respect it currently receives.In the second part Gilson, continuing his debunking analysis, argues that the scholarship on Dante and his use of theories of light has remained captivated by the notion of “the metaphysics of light.” This term, Gilson claims, has been used to unify and oversimplify a rather diverse group of doctrines concerning the nature of light and its relation to knowledge, vision, God, and being. Against the grain of the traditional critical trend, Gilson maintains that Dante's thought has nothing in common with the proper metaphysics of light of a Grosseteste—who identifies light as the primary element of being—and that Dante would have had relatively little contact with Neoplatonic theories of emanation. Again, according to Gilson, in applying the imagery of light to his poetic themes, Dante would have had readily available models in the popular theological light imagery of his time; his use of light in the description of the Empyrean is, Gilson states, perhaps the best example of Dante's relative independence from any limited set of sources.Whether Gilson's informative examination of Dante's relative dependence on sources should be understood as liberating the poet from the anxiety of scientific influence remains, however, an open question. Whatever the extent or depth of any enumeration of those sources, it is the moment of creation that astonishes. (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)

The human fovea is known for its distinctive pit‐like appearance, which results from the displacement of retinal layers superficial to the photoreceptors cells. The photoreceptors are found at high density within the foveal region but not the surrounding retina. Efforts to elucidate the mechanisms responsible for these unique features have ruled out cell death as an explanation for pit formation and changes in cell proliferation as the cause of increased photoreceptor density. These findings have led to speculation that mechanical forces (...) acting within and on the retina during development underly the formation of foveal architecture. Here we review eye morphogenesis and retinal remodeling in human embryonic development. Our meta‐analysis of the literature suggests that fovea formation is a protracted process involving dynamic changes in ocular shape that start early and continue throughout most of human embryonic development. From these observations, we propose a new model for fovea development. (shrink)

_ Source: _Volume 29, Issue 1, pp 39 - 65 Since Euclid, optics has been considered a geometrical science, which Aristotle defines as a “mixed” mathematical science. Hobbes follows this tradition and clearly places optics among physical sciences. However, modern scholars point to a confusion between geometry and physics and do not seem to agree about the way Hobbes mixes both sciences. In this paper, I return to this alleged confusion and intend to emphasize the peculiarity of Hobbes’s (...) geometrical optics. This paper suggests that Hobbes’s conception of geometrical optics, as a mixed mathematical science, greatly differs from Descartes’s one, mainly because they do not share the same “mechanical conception of nature.” I will argue that Hobbes and Descartes also have in common the quest for a different kind of geometry for their optics, different from that of the Ancients. I will show that this departure is not recent since Hobbes’s approach is already evident in 1636, when he judges the demonstrations of his contemporary friends, Claude Mydorge and Walter Warner. Finally the paper broadly suggests what is noteworthy in Hobbes’s optics, that is, the importance of the idea of force in his mechanics, although he was not able to conceptualize it in other terms than “quickness.”. (shrink)

This chapter discusses Thomas Hobbes's statements about the structure of philosophy and suggests that a focus on these reflections has led some scholars to understand Hobbes as an armchair speculative philosopher, both in his own natural‐philosophy endeavors and his well‐known criticisms of Robert Boyle and other experimental philosophers. Beyond Hobbes's statements about natural philosophy, it argues that a more complete understanding of his natural philosophy must also consider his practice of explaining in natural philosophy and optics. Hobbes divides all (...) human knowledge into two parts: scientia, and cognition. These two parts provide different levels of certainty to knowers. The chapter shows that explanations in optics and natural philosophy are ideally a mixture of appeals to everyday sense experience and Hobbes's own a priori geometry by providing two case studies: a case study from Hobbes's optics in De homine II and a case study of Hobbes's explanation of sense in De corpora XXV. (shrink)

Quantum optics does not give a local explanation of the coincidence counts in spatially separated photodetectors. This is the case for a wide variety of phenomena, including the anticorrelated counting rates in the two channels of a beam splitter, the coincident counting rates of the two “photons” in an atomic cascade, and the “antibunching” observed in resonance fluorescence.We propose a local realist theory that explains all of these data in a consistent manner. The theory uses a completely classical description (...) of the electromagnetic field, but with boundary conditions of the far field that are equivalent to assuming a real fluctuating, zero-point field. It is related to stochastic electrodynamics similarly to the way classical optics is related to classical electromagnetic theory.The quantitative aspects of the theory are developed sufficiently to show that there is agreement with all experiments performed till now. (shrink)

The antisaccade task provides a model paradigm that sets the inhibition of a reflexively driven behaviour against the volitional control of a goal-directed behaviour. The stability and adaptability of antisaccade performance was investigated in 23 neurologically healthy individuals. Behaviour and brain function were measured using functional magnetic resonance imaging (fMRI) prior to and immediately following two weeks of daily antisaccade training. Participants performed antisaccade trials faster with no change in directional error rate following two weeks of training; however this increased (...) speed came at the cost of the spatial accuracy of the saccade (gain) which became more hypometric following training. Training on the antisaccade task resulted in increases in fMRI activity in the fronto-basal ganglia-parietal-cerebellar ocular motor network. Following training, antisaccade latency was positively associated with fMRI activity in the frontal and supplementary eye fields, anterior cingulate and intraparietal sulcus; antisaccade gain was negatively associated with fMRI activity in supplementary eye fields, anterior cingulate, intraparietal sulcus and cerebellar vermis. In sum, the results suggest that following training, larger antisaccade latency is associated with larger activity in fronto-parietal-cerebellar ocular motor regions, and smaller antisaccade gain is associated with larger activity in fronto-parietal ocular motor regions. (shrink)

In the previous article (Found. Phys. Lett. 16:325–341, 2003), we showed that a reciprocity of the Gauss sums is connected with the wave and particle complementary. In this article, we revise the previous investigation by considering a relation between the Gauss optics and the Gauss sum based upon the recent studies of the Weil representation for a finite group.

The relativistic optics of the nondispersive media endowed with the metric gij(x) [Eq. (1.6)] and with a nonlinear connection [Eq. (1.2)] is studied. The d-connection [Eqs. (3.3)– (3.4)] relates the conformal and projective properties of the space- time. A post-Newtonian estimation for the metric gij(x) is also given. It is shown that the solar system tests impose a constraint [Eq. (4.20)] on a combination of the post- Newtonian parameters describing the model.

The vestibulo-ocular reflex (VOR) adaptation is an ideal model for investigating how the neurosteroid 17 beta-estradiol (E2) contributes to the modification of behavior by regulating synaptic activities. We hypothesized that E2 impacts VOR adaptation by affecting cerebellar synaptic plasticity at the parallel fiber–Purkinje cell (PF) synapse. To verify this hypothesis, we investigated the acute effect of blocking E2 synthesis on gain increases and decreases in adaptation of the VOR in male rats using an oral dose (2.5 mg/kg) of the (...) aromatase inhibitor letrozole. We also assessed the effect of letrozole on synaptic plasticity at the PF synapse in vitro, using cerebellar slices from male rats. We found that letrozole acutely impaired both gain increases and decreases adaptation of the VOR without altering basal ocular-motor performance. Moreover, letrozole prevented long-term potentiation at the PF synapse (PF-LTP) without affecting long-term depression (PF-LTD). Thus, in male rats neurosteroid E2 has a relevant impact on VOR adaptation and affects exclusively PF-LTP. These findings suggest that E2 might regulate changes in VOR adaptation by acting locally on cerebellar and extra-cerebellar synaptic plasticity sites. (shrink)

This volume contains essays that examine the optical works of Giambattista Della Porta, an Italian natural philosopher during the Scientific Revolution. Coverage also explores the science and technology of early modern optics. Della Porta's groundbreaking book, Magia Naturalis, includes a prototype of the camera. Yet, because of his obsession with magic, Della Porta's scientific achievements are often forgotten. As the contributors argue, his work inspired such great minds as Johanes Kepler and Francis Bacon. After reading this book, researchers, historians, (...) and students will have a better appreciation of this influential scientist. They will also gain a greater understanding of an important period in the history of optics. Readers will learn about Della Porta's experimental method, a process governed by the protocols, aims, and theoretical assumptions of natural magic. Coverage also discusses the material properties and limitations of optical technology in the early 17th century, based on a recently discovered Dutch spyglass. It also demonstrates how diagrams were instrumental in the discovery of the sine law of refraction. In addition, the book includes an in-depth analysis of previously untranslated Latin sources. This makes the material useful to historians of optics unfamiliar with the language. More than 70 illustrations complement the text. (shrink)

Minkowski geometry is axiomatized in terms of the asymmetric binary relation of optical connectibility, using ten first-order axioms and the second-order continuity axiom. An axiom system in terms of the symmetric binary optical connection relation is also presented. The present development is much simpler than the corresponding work of Robb, upon which it is modeled.

I argue that quantum optical experiments that purport to refute Bohr’s principle of complementarity fail in their aim. Some of these experiments try to refute complementarity by refuting the so called particle–wave duality relations, which evolved from the Wootters–Zurek reformulation of BPC. I therefore consider it important for my forgoing arguments to first recall the essential tenets of BPC, and to clearly separate BPC from WZPC, which I will argue is a direct contradiction of BPC. This leads to a need (...) to consider the meaning of particle–wave duality relations and to question their fundamental status. I further argue that particle and wave complementary concepts are on a different footing than other pairs of complementary concepts. (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)

Leonardo's drawings of optical machinery have been used as evidence for the claim that Leonardo built machines to make concave mirrors with which he could project images. This paper argues that Leonardo's drawings cannot be used as evidence for this claim. It will be shown that Leonardo used the drawings to communicate with his patrons and craftsmen, to experiment on paper, to record trials with models, and to think about 'theoretical' problems in optics. At both the theoretical and the (...) practical level, Leonardo was only concerned with the burning properties of concave mirrors, not with their imaging properties. The paper will conclude that the drawings of optical machinery allowed Leonardo to differentiate himself from the ordinary mirror-makers in his workshop. The same drawings, however, also forced him to remain within the conceptual framework of perspectivist optics. (shrink)

Luis Morales Dept. de Psicología y Sociología, Universidad de Zaragoza, España Los movimientos oculares nos informan acerca del procesamiento lingüístico. … Read More →.

Seventeenth-century optics naturalizes the eye while estranging the mind from objects. A mere screen, on which rests a blurry array of light stains, the eye no longer furnishes the observer with genuine re-presentations of visible objects. The intellect is thus compelled to decipher flat images of no inherent epistemic value, accidental effects of a purely causal process, as vague, reversed reflections of wholly independent objects. Reflecting on and trespassing the boundaries between natural and artificial, orderly and disorderly, this optical (...) paradox is a Baroque phenomenon; and it is the origin of Descartes’ celebrated doubt---whether we know anything at all. (shrink)

Socrates, in the Republic , uses the symbol of a divided line to illustrate the distinction between the Visible and Intelligible Worlds, and between the kinds of perception appropriate to each. This paper will present a new hypothesis: that the proportions of the line are derived from optical theory. The construction of the Divided Line is described as follows: Socrates asks his interlocutors to represent the Visible and Intelligible Worlds by a line divided into two unequal segments. The ratio in (...) which the division is to be made is not specified, and it seems that any ratio is acceptable provided that one segment is longer than the other. Socrates then tells them to cut each part again according to the same ratio as the original division. After describing the division of the line thus into four parts, Socrates goes on to explain the philosophical significance of each part. For the purposes of this paper the following brief identification of each segment of the line will suffice. (shrink)

Socrates, in the Republic, uses the symbol of a divided line to illustrate the distinction between the Visible and Intelligible Worlds, and between the kinds of perception appropriate to each. This paper will present a new hypothesis: that the proportions of the line are derived from optical theory. The construction of the Divided Line is described as follows: Socrates asks his interlocutors to represent the Visible and Intelligible Worlds by a line divided into two unequal segments. The ratio in which (...) the division is to be made is not specified, and it seems that any ratio is acceptable provided that one segment is longer than the other. Socrates then tells them to cut each part again according to the same ratio as the original division. After describing the division of the line thus into four parts, Socrates goes on to explain the philosophical significance of each part. For the purposes of this paper the following brief identification of each segment of the line will suffice. (shrink)

The goal of this article is to offer a new model for the study of ocularization in film grounded in the semiotic pragmatism of Charles Sanders Peirce. We first present a literature overview addressing the state of research regarding the theorization of ocularization in film studies. Second, we discuss Peirce’s three universal categories (Firstness, Secondness, and Thirdness) on which our model will be based. Third, we argue how the theme of ocularization in film, as outlined in the first part, can (...) be theorized anew through these categories. This will result in the introduction of a nine-field matrix that will allow us to systemize all kinds of instances of subjectivity in cinema. Lastly, we will demonstrate the empirical usefulness of this model by illustrating each of the matrix’ nine categories through a discussion of Steven Soderbergh’s film Kimi (2022). (shrink)

The postulate that events in peripheral vision enhance activity in the “fixate center” is called into question. An alternative explanation is used to account for the “remote distractor effect.” It is pointed out that a critical element of the model is missing.

During development of the anterior eye segment, cells that originate from the surface epithelium or the neuroepithelium need to interact with mesenchymal cells, which predominantly originate from the neural crest. Failures of proper interaction result in a complex of developmental disorders such Peters' anomaly, Axenfeld–Rieger's syndrome or aniridia. Here we review the role of transcription factors that have been identified to be involved in the coordination of anterior eye development. Among these factors is PAX6, which is active in both epithelial (...) and mesenchymal cells during ocular development, albeit at different doses and times. We propose that PAX6 is a key element that synchronizes the complex interaction of cell types of different origin, which are all needed for proper morphogenesis of the anterior eye. We discuss several molecular mechanisms that might explain the effects of haploinsufficiency of PAX6 and other transcription factors, and the broad variation of the resulting phenotypes. BioEssays 26:374–386, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

Luca Del Baldo's Visionary Academy of Ocular Mentality is an extraordinary testament in the recent history of visual studies. It brings together a group of outstanding scholars who have devoted their lives to art history, philosophy, history, ethnology, focussing predominantly on questions of human perception and imagination. Working from photographs provided by the scholars, Luca del Baldo painted his series of 96 portraits reproduced in this book. The portraits are accompanied by texts written by the persons portrayed, in response (...) to their portrayal, and as an exchange: the artist gifted the original painting to the portrayed person, and the portrayed gifted her or his response. "The result is a unique and profound conversation between image and text focussed on the enigma of the human face in all its mediations.". (shrink)

This volume preserves the format in which Discourse on Method was originally published: as a preface to Descartes's writings on optics, geometry, and meteorology. In his introduction, Olscamp discusses the value of reading the Discourse alongside these three works, which sheds new light on Descartes’s method. Includes an updated bibliography.

We propose an analogy between optical holography and neural behavior as a hypothesis about the physical mechanisms of neural reuse. Specifically, parameters in optical holography (frequency, amplitude, and phase of the reference beam) may provide useful analogues for understanding the role of different parameters in determining the behavior of neurons (e.g., frequency, amplitude, and phase of spiking behavior).

Nineteenth-century optical toys that showcase illusions of motion such as the phenakistoscope, zoetrope, and praxinoscope, have enjoyed active “afterlives” in the twentieth and twenty-first centuries. Contemporary incarnations of the zoetrope are frequently found in the realms of fine art and advertising, and they are often much larger than their nineteenth-century counterparts. This article argues that modern-day optical toys are able to conjure feelings of wonder and spectacle equivalent to their nineteenth-century antecedents because of their adjustment in scale. Exploring a range (...) of contemporary philosophical toys found in arts, entertainment, and advertising contexts, the article discusses various technical adjustments made to successfully “scale up” optical toys, including the replacement of hand-spun mechanisms with larger sources of motion and the use of various means such as architectural features and stroboscopic lights to replace traditional shutter mechanisms such as the zoetrope’s dark slots. Critical consideration of scale as a central feature of these installations reconfigures the relationship between audience and device. Large-scale adaptations of optical toys revise the traditional conception of the user, who is able to tactilely manipulate and interact with the apparatus, instead positing a viewer who has less control over the illusion’s operation and is instead a captive audience surrounded by the animation. It is primarily through their adaptation of scale that contemporary zoetropes successfully elicit wonder as scientific spectacles from their audiences today. (shrink)