Moving from the structure of rites of passage, since Arnold Van Gennep’s renowned work (1909), to the essence of liminality captured by Victor Turner (1967), I propose a neurocognitive anthropological approach dealing with the bistable liminality found in human narrative imaginaries. In a brain-culture nexus, I will examine the liminal phase of the rites of passage by drawing on the enactive cognitive bistability property of the human brain. Recalling that the fundamental property of bistable systems is the alternation of (...) two distinct states of stable equilibrium, I propose a model that identifies the neurocognitive bases on which the transcultural variations of narrative motifs related to metamorphosis can be woven. (shrink)

Slower perceptual alternations, a notable perceptual effect observed in psychiatric disorders, can be alleviated by antidepressant therapies that affect serotonin levels in the brain. While these phenomena have been well documented, the underlying neurocognitive mechanisms remain to be elucidated. Our study bridges this gap by employing a computational cognitive approach within a Bayesian predictive coding framework to explore these mechanisms in depression. We fitted a prediction error (PE) model to behavioral data from a binocular rivalry task, uncovering that significantly higher (...) initial prior precision and lower PE led to a slower switch rate in patients with depression. Furthermore, serotonin‐targeting antidepressant treatments significantly decreased the prior precision and increased PE, both of which were predictive of improvements in the perceptual alternation rate of depression patients. These findings indicated that the substantially slower perception switch rate in patients with depression was caused by the greater reliance on top‐down priors and that serotonin treatment's efficacy was in its recalibration of these priors and enhancement of PE. Our study not only elucidates the cognitive underpinnings of depression, but also suggests computational modeling as a potent tool for integrating cognitive science with clinical psychology, advancing our understanding and treatment of cognitive impairments in depression. (shrink)

Mitotic entry and exit are switch‐like transitions that are driven by the activation and inactivation of Cdk1 and mitotic cyclins. This simple on/off reaction turns out to be a complex interplay of various reversible reactions, feedback loops, and thresholds that involve both the direct regulators of Cdk1 and its counteracting phosphatases. In this review, we summarize the interplay of the major components of the system and discuss how they work together to generate robustness, bistability, and irreversibility. We propose that (...) it may be beneficial to regard the entry and exit reactions as two separate reversible switches that are distinguished by differences in the state of phosphatase activity, mitotic proteolysis, and a dramatic rearrangement of cellular components after nuclear envelope breakdown, and discuss how the major Cdk1 activity thresholds could be determined for these transitions. (shrink)

We have compared two different laser-induced optical light traps for their utility in moving organelles within living animal cells and walled fungal cells. The first trap employed a continuous wave neodymium-yttrium aluminum garnet laser at a wavelength of 1.06 micron. A second trap was constructed using a titanium-sapphire laser tunable from 700 to 1000 nm. With the latter trap we were able to achieve much stronger traps with less laser power and without damage to either mitochondria or spindles. Chromosomes (...) and nuclei were easily displaced, nucleoli were separated and moved far away from interphase nuclei, and Woronin bodies were removed from septa. In comparison, these manipulations were not possible with the Nd-YAG laser-induced trap. The optical force trap induced by the tunable titanium-sapphire laser should find wide application in experimental cell biology because the wavelength can be selected for maximization of force production and minimization of energy absorption which leads to unwanted cell damage. (shrink)

Typically developing 3-day-old newborns take significantly more forward steps on a moving treadmill belt than on a static belt. The current experiment examined whether projecting optic flows that specified forward motion onto the moving treadmill surface would further enhance forward stepping. Twenty newborns were supported on a moving treadmill without optic flow, with optic flow matching the treadmill’s direction and speed, with optic flow in the same direction but at a faster speed, and in a control condition with an incoherent (...) optic flow moving at the same speed as in the Congruent condition but in random directions. The results revealed no significant differences in the number or coordination of forward treadmill steps taken in each condition. However, the Faster condition generated significantly fewer leg pumping movements than the Random control condition. When highly aroused, newborns made significantly fewer single steps and significantly more parallel steps and pumping movements. We speculate the null findings may be a function of the high friction material that covered the treadmill surface. (shrink)

A violation of Bell’s inequalities is generally considered to be the Holy Grail of experimental proof that a specific natural phenomenon cannot be explained in a classical framework and is based on a non-boolean structure of predications. Generalized quantum theory allows for such non-boolean predications. We formulate temporal Bell’s inequalities for cognitive two-state systems and indicate how these inequalities can be tested. This will introduce the notion of temporally non-local measurements. The Necker-Zeno model for bistable perception predicts a violation of (...) these temporal Bell’s inequalities. (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)

_ 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)

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.

The screen is not a pre established object: it becomes a screen—and that screen—when it interacts with a group of elements and relates to a set of practices that produce it as a screen. In this process of becoming screen, a crucial step is played by the space in which the screen is located and where spectators gather. The confluence of screen and space changes our perception of both: the screen displays the situatedness of its action, and the space its (...) nature of medium. The landscape becomes a screenscape, in which individuals access images through which they negotiate with reality and others. Eventually, the insistence on becoming screen highlights the role of contingency and conjuncture in the process of mediation: screenscapes emerge according opportunities, conflicts, and potentialities. Hence a media archeology that, far from being linear and teleological, follows unpredicted paths and creates surprising links—a rhizomatic media archeology. (shrink)

The idea of complementarity already appears in William James’ (1890a, p. 206) Principles of Psychology in the chapter on “the relations of minds to other things”. Later, in 1927, Niels Bohr introduced complementarity as a fundamental concept in quantum mechanics. It refers to properties (observables) that a system cannot have simultaneously, and which cannot be simultaneously measured with arbitrarily high accuracy. Yet, in the context of classical physics they would both be needed for an exhaustive description of the system.

Ayant enquêté auprès de plusieurs jhākri/chamans de l’Himalaya népalais, nous avons pu explorer leur espace liminal, cet « entre-deux » qui sépare le monde des morts de celui des vivants. En cherchant à reconstituer la complexité des rapports entre pratiques rituelles et pratiques narratives des systèmes de croyance hindoue, nous avons considéré ce limen comme un lieu de passage, aux frontières fluides, pour des ontologies surnaturelles et des êtres humains aux pouvoirs exceptionnels, en l’occurrence ces jhākri népalais. À partir des (...) données ethnographiques concernant le rituel d’incorporation au cours duquel ces chamans himalayens peuvent fusionner avec leur esprit tutélaire, nous avons développé un modèle en nous basant sur une propriété du cerveau confirmée depuis la Gestalt : sa bistabilité cognitive enactive. L’incorporation, qui prend place en phase liminale, se déroule bien selon un cycle bistable, avec une alternance constante de deux expressions formelles, métemmorphoses, chacune potentiellement stable en mode fusionnel ou ségrégationnel. C’est là selon nous que réside tout le « secret » du succès de telles conceptions métemphysiques autour de la métemsomatose, hypertrophiée chez le jhākri passeur intra mundi en mode bistable. Our recent investigations among several jhākri/shamans from the Nepal Himalaya allowed us to identify a liminal “in-between” space, separating the world of the dead from the living one. From the relationship between ritual practices and narratives in Hindu beliefs, we can consider this limen, with fluid boundaries, as a crossing point for different supernatural ontologies and for a few human beings with exceptional powers, Nepalese jhākris. To cope with the ethnographic data about the incorporation ritual, when these shamans may fuse with their tutelary spirit, we had to dwell on a model repeatedly fed since Gestalt findings, endowing the brain with an enactive cognitive bistability property. This incorporation ritual which takes place in the liminal phase, evolves in such a bistability cycle, with two alternating morphings, each potentially stable in a fusion or segregation mode. Her lies the core for the success of such metemphysical concepts about metensomatosis, overdeveloped in the jhākri as a bistable intermediary intra mundi. (shrink)

A mathematical model based upon catastrophe theory is derived to describe the kinematics of the wing beat in Dipteran flight. The parameters of the model correspond to anatomical and physiological characteristics of the insect.

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)

Ever since Big Data became a mot du jour across social fields, optical metaphors such as the microscope began to surface in popular discourse to describe and qualify its epistemological impact. While the persistence of optics seems to be at odds with the datafication of vision, this article suggests that the optical metaphor offers an opportunity to reflect about the material consequences of the modes of seeing and knowing that currently shape datafied worlds. Drawing on feminist new materialism, (...) the article investigates the optical metaphor as a material-discursive practice that actively constitutes the world, as metaphors imply modes of thinking, knowing and doing that have material enactions. Expanding visual culture theories, the notion of ‘optical unconscious’ is taken up to discuss the tensions between displacement and persistence of optics within datafied worlds, that is, how optical vision is displaced but also mobilised and repurposed by data-driven knowledge. In dialogue with feminist science and technology studies and speculative ethics, I suggest that the datafication of vision offers a chance to reconceptualize the sense of sight towards a sensorial engagement with Big Data premised on responsibility, care, and an ethics of unknowability. Within this framework, vision may be conceived differently, perhaps not only as enhancement and control, but as generator of new possibilities. Ultimately, the article proposes that the visual theories after which Big Data is being imagined matter not only for our understanding of Big Data's epistemic potential, but also for the possibility of shaping emerging data worlds. (shrink)

A novel conceptual framework for theoretical psychology is presented and illustrated for the example of bistable perception. A basic formal feature of this framework is the non-commutativity of operations acting on mental states. A corresponding model for the bistable perception of ambiguous stimuli, the Necker–Zeno model, is sketched and some empirical evidence for it so far is described. It is discussed how a temporal non-locality of mental states, predicted by the model, can be understood and tested.

People with grapheme-color synesthesia perceive specific colors when viewing different letters or numbers. Previous studies have suggested that synesthetic color experience can be bistable when induced by an ambiguous character. However, the exact relationship between processes underlying the identity of an alphanumeric character and the experience of the induced synesthetic color has not been examined. In the present study, we explored this by focusing on the temporal relation of inducer identification and color emergence using inducers whose identity could be rendered (...) ambiguous upon rotation of the characters. Specifically, achromatic alphabetic letters and digits were presented at varying angles to 9 grapheme-color synesthetes. Results showed that grapheme identification and synesthetically perceived grapheme color covary with the orientation of the test stimulus and that synesthetes were slower naming the experienced color than identifying the character, particularly at intermediate angles where ambiguity was greatest. (shrink)

A major intellectual shift between Copernicus and the mid-17th century was the rejection of Aristotelian assertions concerning the relationship of mathematics to physical nature. Aristotle asserted that “The minute accuracy of mathematics is not to be demanded in all cases, but only in the case of things which have no matter. Therefore its method is not that of natural science; for presumably all nature has matter.” Thus, he pulled out the rug from under the feet of the aspiration to a (...) mathematically based natural sciences, asserting that: “And at the same time not even this is true, that mensuration deals with perceptible and perishable magnitudes; for then it would have perished, when they perished. And astronomy also cannot be dealing with perceptible magnitudes nor with this heaven above us. For neither are perceptible lines such lines as the geometer speaks of, nor are the movement and complex orbits in the heaven like those which astronomy treats, nor have geometrical points the same nature as the actual stars.”. (shrink)

Descartes's Dioptrics is more than a mere technical treatise on optics; it is an essay in the "practical philosophy" that he claimed could render us "masters and possessors of nature." Descartes's practical intent is indicated first by the instrumentalist character of his derivation of the sine law of refraction, which is based on a heuristic and readily mathematizable model that requires no consideration of light's "true nature." Descartes's subsequent discussion of human vision is an extended critique of nature's workmanship that (...) grounds the possibility of improving vision by artificial means. I suggest that this critique is the source of Descartes's doctrine that the purpose of sensory perception is to preserve the mind-body composite, not to provide knowledge of the essential nature of things. Accordingly, the ultimate goal of the Dioptrics is to "master" human vision by raising it from a mere means of self-preservation to an instrument of scientific knowledge. -/- . (shrink)

This book is a long-term history of optics, from early Greek theories of vision to the nineteenth-century victory of the wave theory of light. It is a clear and richly illustrated synthesis of a large amount of literature, and a reliable and efficient guide for anyone who wishes to enter this domain.

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.

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)

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)

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)

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)

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.