In psychophysical experiments, the use of a psychophysical procedure of brightness/darkness cancellation shed light on interactions between spatial arrangement and figure–ground contrast in the perceptual filling in of achromatic and colored surfaces.Achromatic and chromatic Kanizsa squares with varying contrast, contrast polarity, and inducer spacingwere used to test how these factors interact in the perceptual filling in of surface brightness or darkness. The results suggest that the neuronal processing of surfaces with apparent contrast, leading to figure–ground segregation (...) (i.e., perceptual organization), is governed by mechanisms that integrate both luminance contrast and spatial information carried by the inducing stimuli, while discarding information on contrast polarity or color. The findings are discussed in relation to earlier observations on brightness assimilation and contrast. They support theories of nonantagonistic neural mechanisms suppressing local contrast or color signs in brightnessbased figure–ground percepts. Such mechanismsmight be necessary to cancel potentially conflicting polarities in geometricallycomplex visual stimuli so that perceptual filling in resulting in the most plausible representation of figure and ground can be achieved. (shrink)

Poorly saturated colors are closer to a pure grey than strongly saturated ones and, therefore, appear less “colorful”. Color saturation is effectively manipulated in the visual arts for balancing conflicting sensations and moods and for inducing the perception of relative distance in the pictorial plane. While perceptual science has proven quite clearly that the luminance contrast of any hue acts as a self-sufficient cue to relative depth in visual images, the role of color saturation in such figure-ground organization (...) has remained unclear. We presented configurations of colored inducers on grey ‘test’ backgrounds to human observers. Luminance and saturation of the inducers was uniform on each trial, but varied across trials. We ran two separate experimental tasks. In the relative background brightness task, perceptual judgments indicated whether the apparent brightness of the grey test background contrasted with, assimilated to, or appeared equal (no effect) to that of a comparison background with the same luminance contrast. Contrast polarity and its interaction with color saturation affected response proportions for contrast, assimilation and no effect. In the figure-ground task, perceptual judgments indicated whether the inducers appeared to lie in front of, behind, or in the same depth with the background. Strongly saturated inducers produced significantly larger proportions of foreground effects indicating that these inducers stand out as figure against the background. Weakly saturated inducers produced significantly larger proportions of background effects, indicating that these inducers are perceived as lying behind the backgrounds. We infer that color saturation modulates figure-ground organization, both directly by determining relative inducer depth, and indirectly, and in interaction with contrast polarity, by affecting apparent background brightness. The results point towards a hitherto undocumented functional role of color saturation in the genesis of form, and in particular figure-ground percepts in the absence of chromatostereopsis. (shrink)

The thresholds of human observers detecting line targets improve significantly when the targets are presented in a spatial context of collinear inducing stimuli. This phenomenon is referred to as spatial facilitation, and may reflect the output of long-range interactions between cortical feature detectors. Spatial facilitation has thus far been observed with luminance-defined, achromatic stimuli on achromatic backgrounds. This study compares spatial facilitation with line targets and collinear, edge-like inducers defined by luminance contrast to spatial facilitation with targets (...) and inducers defined by color contrast. The results of a first experiment show that achromatic inducers facilitate the detection of achromatic targets on gray and colored backgrounds, but tend to suppress the detection of chromatic targets. Chromatic inducers facilitate the detection of chromatic targets on gray and colored backgrounds, but tend to suppress the detection of achromatic targets. Chromatic spatial facilitation appears to be strongest when inducers and background are isoluminant. The results of a second experiment show that spatial facilitation with chromatic targets and inducers requires a longer exposure duration of the inducers than spatial facilitation with achromatic targets and inducers, which is already fully effective at an inducer exposure of 30 ms only. The findings point towards two separate mechanisms for spatial facilitation with collinear form stimuli: one that operates in the domain of luminance, and one that operates in the domain of color contrast. These results are consistent with neural models of boundary and surface formation which suggest that achromatic and chromatic visual cues are represented on different cortical surface representations that are capable of selectively attracting attention. Multiple copies of these achromatic and chromatic surface representations exist corresponding to different ranges of perceived depth from an observer, and each can attract attention to itself. Color and contrast differences between inducing and test stimuli, and transient responses to inducing stimuli, can cause attention to shift across these surface representations in ways that sometimes enhance and sometimes interfere with target detection. (shrink)

Less salient, lower contrast disks appear to be more numerous than more salient, higher contrast disks when intermingled in equal numbers into the same display, but they are equal in perceived numerosity when segregated into different displays. Comparative judgements indicate that the apparent numerosity of the lower contrast disks is unaffected by being intermingled with high contrast disks, whereas the high contrast disks are reduced in numerosity by being intermingled with the low contrast ones. (...) Here, we report that this illusion also occurs for absolute judgements of the numerosities of displays of from 20 to 80 disks. A model based on luminance-difference contrast normalization explains the illusory loss of high-contrast items along with veridical perception of the low-contrast ones. The model correctly predicts that perceived numerosity is linearly related to the square-root of the number of disks, with the extent of the illusion depending on an attentionally-weighted function of contrast and assimilation. (shrink)

Brincat and Westheimer [Journal of Neurophysiology 83 (2000) 1900] have reported facilitating interactions in the discrimination of spatially separated target orientations and co-linear inducing orientations by human observers. With smaller gaps between stimuli (short-range effects), facilitating interactions were found to depend on the contrast polarity of the stimuli. With larger gaps (longrange effects), only co-linearity of the stimuli seemed necessary to produce facilitation. In our study, the dependency of facilitating interactions on the intensity (luminance) of line stimuli is (...) investigated by measuring detection thresholds for a target line separated from the end of an inducing line by co-axial gaps ranging from 5 to 200 min of visual arc. We find facilitating interactions between target and inducing orientations, producing short-range and long-range effects similar to those reported by Brincat and Westheimer. In addition, detection thresholds as a function of the co-axial separation between target and inducing line reveal an interaction between the spatial regime of facilitating effects and the luminance of the stimuli. Short-range effects are found to be sensitive to changes in local intensity while long-range effects remain unaffected. (shrink)

The purpose of the present study was two-fold. First we examined whether visible motion appearance was altered by the spatial interaction between invisible and visible motion. We addressed this issue by means of simultaneous motion contrast, in which a horizontal test grating with a counterphase luminance modulation was seen to have the opposite motion direction to a peripheral inducer grating with unidirectional upward or downward motion. Using a mirror stereoscope, observers viewed the inducer and test gratings with one (...) eye, and continuous flashes of colorful squares forming an annulus shape with the other eye. The continuous flashes rendered the inducer subjectively invisible. The observers’ task was to report whether the test grating moved upward or downward. Consequently, simultaneous motion contrast was observed even when the inducer was invisible . Second, we examined whether the observers could correctly respond to the direction of invisible motion: It was impossible. (shrink)

It has been suggested that luminance edges in retinal images are potential cues for glossiness perception, particularly when the perception relies on low-luminance specular regions. However, a previous study has shown only statistical correlations between luminance edges and perceived glossiness, not their causal relations. Additionally, although specular components should be embedded at various spatial frequencies depending on the micro-roughness on the object surface, it is not well understood what spatial frequencies are essential for glossiness perception on objects (...) with different micro-roughness. To address these issues, we examined the impact of a sub-band contrast enhancement on the perceived glossiness in the two conditions of stimuli: the Full condition where the stimulus had natural specular components and the Dark condition where it had specular components only in dark regions. Object images with various degrees of surface roughness were generated as stimuli, and their contrast was increased in various spatial-frequency sub-bands. The results indicate that the enhancement of the sub-band contrast can significantly increase perceived glossiness as expected. Furthermore, the effectiveness of each spatial frequency band depends on the surface roughness in the Full condition. However, effective spatial frequencies are constant at a middle spatial frequency regardless of the stimulus surface roughness in the Dark condition. These results suggest that, for glossiness perception, our visual system depends on specular-related information embedded in high spatial frequency components but may change the dependency on spatial frequency based on the surface luminance to be judged. (shrink)

Luminance and color are strong and self-sufficient cues to pictorial depth in visual scenes and images. The present study investigates the conditions Under which luminance or color either strengthens or overrides geometric depth cues. We investigated how luminance contrasts associated with color contrast interact with relative height in the visual field, partial occlusion, and interposition in determining the probability that a given figure is perceived as ‘‘nearer’’ than another. Latencies of ‘‘near’’ responses were analyzed to test (...) for effects of attentional selection. Figures in a pair were supported by luminance contrast or isoluminant color contrast and combined with one of the three geometric cues. The results of Experiment 1 show that luminance contrasts associated with hue, when it does not interact with other hues, produces the same effects as achromatic luminance contrasts: The probability of‘‘near’’ increases with luminance contrast while the latencies for ‘‘near’’ responses decrease. Partial occlusion is found to be a strong enough pictorial cue to support a weaker red luminance contrast. Interposition cues lose out against cues of spatial position and partial occlusion. The results of Experiment 2, with isoluminant displays of varying color contrast, reveal that red color contrast on a light background supported by any of the three geometric cues wins over green or white supported by any of the three geometric cues. On a dark background, red color contrast supported by the interposition cue loses out against green or white color contrast supported by partial occlusion. These findings reveal that color is not an independent depth cue, but is strongly influenced by luminance contrast and stimulus geometry. Systematically shorter response latencies for stronger ‘‘near’’ percepts demonstrate that selective visual attention reliably detects the most likely depth cue combination in a given configuration. (shrink)

Victor Vasarely's (1906–1997) important legacy to the study of human perception is brought to the forefront and discussed. A large part of his impressive work conveys the appearance of striking three-dimensional shapes and structures in a large-scale pictorial plane. Current perception science explains such effects by invoking brain mechanisms for the processing of monocular (2D) depth cues. Here in this study, we illustrate and explain local effects of 2D color and contrast cues on the perceptual organization in terms of (...) figure-ground assignments, i.e. which local surfaces are likely to be seen as “nearer” or “bigger” in the image plane. Paired configurations are embedded in a larger, structurally ambivalent pictorial context inspired by some of Vasarely's creations. The figure-ground effects these configurations produce reveal a significant correlation between perceptual solutions for “nearer” and “bigger” when other geometric depth cues are missing. In consistency with previous findings on similar, albeit simpler visual displays, a specific color may compete with luminance contrast to resolve the planar ambiguity of a complex pattern context at a critical point in the hierarchical resolution of figure-ground uncertainty. The potential role of color temperature in this process is brought forward here. Vasarely intuitively understood and successfully exploited the subtle context effects accounted for in this paper, well before empirical investigation had set out to study and explain them in terms of information processing by the visual brain. (shrink)

We show that true colors as defined by Chevreul (1839) produce unsuspected simultaneous brightness induction effects on their immediate grey backgrounds when these are placed on a darker (black) general background surrounding two spatially separated configurations. Assimilation and apparent contrast may occur in one and the same stimulus display. We examined the possible link between these effects and the perceived depth of the color patterns which induce them as a function of their luminance contrast. Patterns of square-shaped (...) inducers of a single color (red, green, blue, yellow, or grey) were placed on background fields of a lighter and a darker grey, presented on a darker screen. Inducers were always darker on one side of the display and brighter on the other in a given trial. The intensity of the grey backgrounds varied between trials only. This permitted generating four inducer luminance contrasts, presented in random order, for each color. Background fields were either spatially separated or consisted of a single grey field on the black screen. Experiments were run under three environmental conditions: dark-adaptation, daylight, and rod-saturation after exposure to bright light. In a first task, we measured probabilities of contrast, assimilation, and no effect in a three-alternative forced-choice procedure (background appears brighter on the ‘left’, on the ‘right’ or the ‘same’). Visual adaptation and inducer contrast had no significant influence on the induction effects produced by colored inducers. Achromatic inducers produced significantly stronger contrast effects after dark-adaptation, and significantly stronger assimilation in daylight conditions. Grouping two backgrounds into a single one was found to significantly decrease probabilities of apparent contrast. Under the same conditions, we measured probabilities of the inducers to be perceived as nearer to the observer inducers. These, as predicted by Chevreul’s law of contrast, were determined by the luminance contrast of the inducers only, with significantly higher probabilities of brighter inducers to be seen as nearer, and a marked asymmetry between effects produced by inducers of opposite sign. Implications of these findings for theories which attempt to link simultaneous induction effects to the relative depth of object surfaces in the visual field are discussed. (shrink)

The experiments reported herein probe the visual cortical mechanisms that control near–far percepts in response to two-dimensional stimuli. Figural contrast is found to be a principal factor for the emergence of percepts of near versus far in pictorial stimuli, especially when stimulus duration is brief. Pictorial factors such as interposition (Experiment 1) and partial occlusion Experiments 2 and 3) may cooperate, as generally predicted by cue combination models, or compete with contrast factors in the manner predicted by the (...) FACADE model. In particular, if the geometrical conŽ guration of an image favors activation of cortical bipole grouping cells, as at the top of a T-junction, then this advantage can cooperate with the contrast of the conŽ guration to facilitate a near–far percept at a lower contrast than at an X-junction. Varying the exposure duration of the stimuli shows that the more balanced bipole competition in the X-junction case takes longer exposure times to resolve than the bipole competition in the T-junction case (Experiment 3). (shrink)

Over the history of the study of visual perception there has been great success at discovering countless visual illusions. There has been less success in organizing the overwhelming variety of illusions into empirical generalizations (much less explaining them all via a unifying theory). Here, this article shows that it is possible to systematically organize more than 50 kinds of illusion into a 7 × 4 matrix of 28 classes. In particular, this article demonstrates that (1) smaller sizes, (2) slower speeds, (...) (3) greater luminance contrast, (4) farther distance, (5) lower eccentricity, (6) greater proximity to the vanishing point, and (7) greater proximity to the focus of expansion all tend to have similar perceptual effects, namely, to (A) increase perceived size, (B) increase perceived speed, (C) decrease perceived luminance contrast, and (D) decrease perceived distance. The detection of these empirical regularities was motivated by a hypothesis, called “perceiving the present,” that the visual system possesses mechanisms for compensating neural delay during forward motion. This article shows how this hypothesis predicts the empirical regularity. (shrink)

We have used fMRI to measure responses to chromatic and achromatic contrast in retinotopically defined regions of macaque and human visual cortex. We make four observations. Firstly, the relative amplitudes of responses to color and luminance stimuli in macaque area V1 are similar to those previously observed in human fMRI experiments. Secondly, the dorsal and ventral subdivisions of macaque area V4 respond in a similar way to opponent (L j M)-cone chromatic contrast suggesting that they are part (...) of a single functional area. Thirdly, we find that macaque area V4, like area V1, responds preferentially to chromatic contrast compared to luminance contrast and the degree of preference is strongly influenced by the temporal frequency of the stimulus. Finally, we observe that while macaque V4d is a region on the dorsal surface of the macaque visual cortex that responds robustly to chromatic stimuli, human chromatic responses to identical stimuli are largely confined to the ventral surface suggesting a fundamental difference in the topographical organization of higher visual areas between humans and macaques. (shrink)

Chromatic induction is a major contextual effect of color appearance. Patterned backgrounds are known to induce strong chromatic induction effects. However, it has not been clarified whether the spatial extent of the chromatic surrounding induces a chromatic contrast or assimilation effects. In this study, we examined the influence of the width of a center line and its flanking white contour on the color appearance when the line was surrounded by chromatic backgrounds. A strong color shift was observed when the (...) center line was flanked by white contours with the L/M- and S-cone chromatic backgrounds. There was a difference between the optimal widths of the center line and the contour for the shift in color appearance for the L/M-cone chromaticity and the S-cone chromaticity. The optimal width of the center line for the L/M-cone was finer than the resolution-limit width of the chromatic contrast sensitivity and coarser than that of the luminance contrast sensitivity. Thus, the color appearance of the center line could be obtained by integrating broad chromatic information and fine luminance details. Due to blurring and chromatic aberrations, the simulated artifact was large for the darker center line and S-cone background, thus suggesting that the artifact could explain the luminance dependency of the induction along the S-cone chromaticity. Moreover, the findings of this study reveal that the dominant factor of the color shift is neural instead of optical. (shrink)

Spatial facilitation has been observed with luminance-defined, achromatic stimuli on achromatic backgrounds as well as with targets and inducers defined by colour contrast. This paper reviews psychophysical results from detection experiments with human observers showing the conditions under which spatially separated contour inducers facilitate the detection of simultaneously presented target stimuli. The findings point towards two types of spatial mechanisms: (i) Short-range mechanisms that are sensitive to narrowly spaced stimuli of small size and, at distinct target locations, selective (...) to the contrast polarity of targets and inducers. (ii) Long-range mechanisms that are triggered by longer stimuli, generate facilitation across wider spatial gaps between targets and inducers, and are insensitive to their contrast polarity. Spatial facilitation with chromatic stimuli requires a longer inducer exposure than spatial facilitation with achromatic stimuli, which is already fully effective at inducer exposures of 30 ms. This difference in temporal dynamics indicates some functional segregation between mechanisms for colour and luminance contrast in the perception of space. (shrink)

In contrast to the Nietzschean conception of Übermensch as signifying, hitherto, a supermanhood in moral terms alone, the principle of the latter lies in its being antithetical to the present human status, and in its thus proving altogether superior both ontologically and physically. With this premise the notions of Sixth Force and Photonic Frame are now associated. Set forth after a qualitative fashion, while the former is related to the thus far known elemental constituents of matter, as well as (...) to forces and interactions between matter particles, and under this form deemed to intangibly account for all the chaos, indeterminacy and otherwise imperfection or limit found so peculiar to man, the latter refers to an ultimate trait in the actual Overman touching a most luminous and unparalleled corporeality. An original conception of geometry in photonic terms is also propounded. Illustrations meeting at length with a semiotic process and literary hints add to the suggestion. (shrink)

I am aware of the tree and its leaves, but am I aware of my awareness of these things? When I try to introspect my awareness, I just find myself attending to objects and their properties. This observation is known as the ‘transparency of experience’. On the other hand, I seem to directly know that I am aware. Given the first observation, it is not clear how I know that I am aware. Fred Dretske thought that the problem was so (...) acute that he issued the challenge of answering ‘How do you know that you are not a zombie?’ I propose that a view found in the Advaita Vedanta, that awareness is self luminous, reconciles these two observations. I understand self-luminosity as the thesis that: (1) I am implicitly aware of my awareness and (2) I am phenomenally aware of a distinct phenomenal character of my awareness. In support of the first claim, that I apparently only attend to objects in the world when introspecting perceptual experience, suggests that I do not know my awareness explicitly, but rather that I must know it implicitly. In support of the second claim, I argue that the mere fact that I am perceptually conscious is not sufficient to allow me to know that I am perceptually conscious. In particular, the qualities I am perceptually aware of do not tell me that I aware of them, rather they just seem to be properties of objects. I also assess whether strategies for responding to Cartesian sceptical scenarios can be employed against Dretske’s consciousness scepticism. I argue that these strategies either fail to distinguish me from a zombie or they do not adequately describe my epistemic situation. By contrast to other accounts, if awareness has its own distinct phenomenal character, then it cannot be considered to be a prima facie property of the world, hence the self-luminosity of awareness provides a plausible account of how I know that I’m not a zombie. (shrink)

Where was your soul before you were born? If your soul is immortal, did it have a "life" prior to birth? Did you choose your life and parents? Is reincarnation real? Elizabeth and Neil Carman, the authors of Cosmic Cradle, address these questions through interviews with adults and children who report pre-birth experiences (PBEs) not based on regression, hypnosis, or drugs. Instead, interviewees recall their pre-birth existence completely sober and awake. In contrast to near-death experiences (NDEs), which have been (...) well documented to show us what the soul experiences after death, PBEs throw light upon our lives before birth. People with NDEs sense that they "return home" when their spirits cross to the other side. What is the nature of this place we "return" to? PBEs suggest that we come from the same place we return to: we come from the Light and return to the Light. The same eternal "you" progresses through life before life, human life, and life after death. This new edition of Cosmic Cradle explores your soul's journey into your mother's womb--where your soul comes from, the origin and purpose of your life, and the process by which you entered an earthly body. In pre-birth communications, parents meet a soul seeking to cross over from the heavenly realm to human birth. Persons with pre-birth memories recall existence in a luminous world before birth, in which they preview the upcoming life with a Divine Planner, and recall how they journeyed to their mothers' wombs. Contents Foreword by Bernie Siegel, MD Introduction: Amnesia of Our Spiritual Origins Part One: Pre-Birth Memory 1. Children as Messengers 2. Memories of the Cosmic Cradle 3. “I Was in Your Tummy Twice” 4. Scanning Soul Plans: Contemporary Pre-Birth Memories 5. Welcome to Planet Earth 6. Shirley Temple and the Blue Bird 7. Our Soul as a Tiny Spaceship 8. I Saw All My Costumes Part Two: Pre-Birth Communications 9. Souls Waiting in the Wings for Birth 10. Soul as a Sphere of Light 11. Cosmic Conception 12. Miscarriages and Stillbirths in the Light of Pre-Birth Plans 13. Conversations with Unborn Children Part Three: Pre-Birth Wisdom down through History 14. Spirit-Children Down Under 15. Lodge of the Great Manitou 16. The Cosmic Designer 17. Travelers from the Light 18. Journey from Forgetting to Remembering. (shrink)

Justification as Ignorance offers an original account of epistemic justification as both non-factive and luminous, vindicating core internalist intuitions without construing justification as an internal condition knowable by reflection alone. Sven Rosenkranz conceives of justification, in its doxastic and propositional varieties, as a kind of epistemic possibility of knowing and of being in a position to know. His account contrasts with recent alternative views that characterize justification in terms of the metaphysical possibility of knowing. Instead, he develops a suitable non-normal (...) multi-modal epistemic logic for knowledge and being in a position to know that respects the finding that these notions create hyperintensional contexts. He also defends his conception of justification against well-known anti-luminosity arguments, shows that the account allows for fruitful applications and principled solutions to the lottery and preface paradoxes, and provides a metaphysics of justification and its varying degrees of strength that is compatible with core assumptions of the knowledge-first approach and disjunctivist conceptions of mental states. (shrink)

Perceptual-role theories of mental qualities hold that we can discover the nature of a being’s mental qualities by investigating that being’s capacity to make perceptual discriminations. Many advocates of perceptual-role theories hold that the best explanation of these capacities is that mental quality spaces are homomorphic to the spaces of the physical properties that they help to discriminate. This paper disputes this thesis on largely empirical grounds, and offers an alternative. The alternative explains interesting patterns in our perception of color (...) differences and similarities across edges, emphasizing the importance of visual discontinuities. Further, it provides a simple explanation of the intransitivity of indiscriminability. The homomorphism thesis can explain this intransitivity only with the addition of an independently unsupported empirical hypothesis. Also, in contrast to the homomorphism thesis, the alternative view is perfectly consistent with empirical data that suggest that the visual system uses the dynamic allocation of a limited range of responses in order to discriminate a wider range of physical stimuli and that we are much better at detecting changes in relative luminance than changes in absolute luminance. Moreover, it does all this while using a more efficient strategy for encoding sensory information. (shrink)

It remains unclear what is being processed in blindsight in response to faces, colours, shapes, and patterns. This was investigated in two hemianopes with chromatic and achromatic stimuli with sharp or shallow luminance or chromatic contrast boundaries or temporal onsets. Performance was excellent only when stimuli had sharp spatial boundaries. When discrimination between isoluminant coloured Gaussians was good it declined to chance levels if stimulus onset was slow. The ability to discriminate between instantaneously presented colours in the hemianopic (...) field depended on their luminance, indicating that wavelength discrimination totally independent of other stimulus qualities is absent. When presented with narrow-band colours the hemianopes detected a stimulus maximally effective for S-cones but invisible to M- and L-cones, indicating that blindsight is mediated not just by the mid-brain, which receives no S-cone input, or that the rods contribute to blindsight. The results show that only simple stimulus features are processed in blindsight. (shrink)

I will present a novel account of justification in terms of knowledge on which one is justified in believing p just in case one could know that p. My main aim is to unravel some of the formal properties that justification has in virtue of its connection to knowledge. Assuming that safety is at least a necessary condition for knowledge, I show that justification doesn’t iterate trivially; isn’t a luminous condition; is closed under a certain kind of multi-premise closure principle, (...) but; surprisingly one can nevertheless believe with justification a set of claims that’s jointly inconsistent. This last feature allows for a rather satisfying solution to the preface paradox. Finally, I contrast my account with other knowledge-first accounts of justification. (shrink)

Meditation hasrecently emerged as a topic of interest for the medicinal scientists as well as for the neuropsychological scientists for different reasons. The methods used by both of these approaches have been mostly objective. This quest of objectification has led to vigorous use of tools like EEG and ERP, which has definitely led to revealing of marvellous aspects of meditation. However, the subjective states of meditation have been much less explored, especially when seen in contrast to the objective states. (...) The need of the hour is to use the qualitative methods for exploration of these states because these methods better depict the unique experiences of meditation. In this context, we conducted a qualitative study in the form of Interpretative phenomenological analysis to explore the subjective experiences associated with the inner-light perception of a group of meditators practising the meditation technique of Vihangam Yoga. It is an ancient meditation technique of India, initiated by HH Sadguru Sadafal Deoji Maharaj in the year 1924 and now being propogated by HH Sadguru Swatantra Deoji Maharaj. When asked in detail, the practitioners often report of many mystique experiences. This particular Yoga group was chosen because in a survey of among four groups, the maximum number of confident mediators reporting of perceiving some sort of luminance during meditation was found in this group. For this study, the inner-light perception experience of this meditation was chosen because of the divine value attached to this experience across all the cultures and religions. This experience was also chosen because of the great impact on their lives that Vihangam Yogis attributed to this experience. As the results of the study, four major themes were obtained which were: Uniqueness of the nature of light Experiences during light perception Explanations of the source of light Change in outlook towards world and associated changes in thinking. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Journal of the History of Philosophy 41.2 (2003) 268-269 [Access article in PDF] A. A. Long. Epictetus: A Stoic and Socratic Guide to Life. New York: Oxford University Press, Clarendon Press, 2002. Pp. xiv + 310. Cloth, $29.95. Anthony Long's new book on Epictetus is a signal achievement for which scholars of Hellenistic philosophy, historians of intellectual culture, and thoughtful people generally ought to feel an enormous gratitude. And (...) here's why: Epictetus, a Greek philosopher (ca. 50-ca. 135 AD) in the Roman Empire, was popular in his own day and was influential with Marcus Aurelius as well as with Christian writers in the medieval period. Often cited and quoted, his influence perhaps reached an acme in the seventeenth and eighteenth centuries. His reputation languished in the nineteenth and most of the twentieth century. And even toward the end of the twentieth century—barring the interest of a handful of scholars—Epictetus was regarded primarily as a popularizer of Stoicism. Against this background Long's luminous study of Epictetus's philosophy can be measured, for what Long has done is to make us see that Epictetus is an important philosopher in his own right and not merely a popular purveyor of Stoic thought. He has done this by expounding three of the fundamental strands in Epictetus's thought. One is the immense role that Socrates plays in [End Page 268] Epictetus's teaching. The second is the unique character of Epictetus's teaching method—conversational and directly confrontational. And, thirdly, is the emphatic way in which Epictetus attempts to inculcate the Stoic doctrine that he found most congenial for the conduct of human life: that a human being's happiness and destiny is in his own power. For in his power and only in his power are those things alone which will secure him that happiness: his judgments and his desires. There is much else in Long's lucid account but by his emphasis on these themes and his inclusion of key passages he has translated from the Discourses he has with keen discernment brought to the world's attention both the cultural significance and the philosophical importance of this neglected philosopher. I now consider these themes in turn.In "the most creative appropriation of Socrates subsequent to the works of Plato and Xenophon" (94), Epictetus applies Socratic elenchus in his educational practice, for he uses it in conversational contexts to expose inconsistencies in students' preconceptions (regarding the desirability of goodness and the identity of goodness with the advantageous) and their judgments about the goodness or badness of some particular thing. In fact, part of Long's argument that Epictetus's discourses are wrongly construed as diatribes or sermons is that on analysis they can often be shown to be elenctic conversations in which the aim is to expose contradictions in a student's belief, say, that the happy life consists in the pursuit of what is advantageous and that running away from a dying daughter is an advantageous thing to do. More generally, the student is made to concentrate his attention on his preconceptions and motivations. While Long emphasizes the extent to which Epictetus, more than any other Stoic, appropriates Socratic elenchus in his educational methodology, he also, while directing attention to another aspect of that methodology, points out Epictetus's major departure from Socrates' use of elenchus. In Plato's Dialogues Socrates is always represented as engaged in conversations with others. Epictetus, by contrast, seems most bent on encouraging the student to engage in dialogue with himself, to try in an interior conversation with himself to bring to the surface of consciousness conflicts between his own moral preconceptions and motivations, on the one hand, and particular value judgments, on the other; and, in this way, to use the internal elenchus as his "principal instrument of moral progress" (86).Epictetus makes volition the central element in a human being's identity, character, and purpose. In the domain of volition are the only two things that are up to the individual—assents to impressions and... (shrink)

For Vajrayana Buddhism, the now is an interval, a boundary, a point of tension and suspension with an atmosphere of uncertainty. It is a bifurcation point of variable length; its name is “bardo.” The bardo is immersed in the conventional, or “seeming” reality. It emerges from what is called the “unstained” ultimate or primordial emptiness or “basal clear light.” Further, the ultimate is not the sphere of cognition. Cognition, including cognition of time, belongs to conventional reality. Buddhahood, in contrast, (...) is a condition of uncompounded knowledge where basic mind blossoms without temporal or other cognitive distinctions, unmade, unfabricated, luminous and pristine. Cyclical existence involves both the ultimate and the conventional as it moves through six bardos—all of which are the effulgent of the basal clear light—until Buddhahood. The six are: the bardo of this life ; the bardo of dream; the bardo of meditation; the bardo of dying; the bardo of dharmata ; and the bardo of existence. Each realm is both ultimate and conventional, and has specific initiation-based yogas to investigate these differences. The process of transition from one to the next involves at least three bodies, one mind, and aspects of speech. In each bardo, the character of the now as embodiment and temporal knowing varies yet a complete and consistent cross-bardo yogic wisdom leads to its total cessation in the basal clear light; the now is extinguished. The author presents, from the viewpoint of a knowledgeable practitioner of over 30 years, an essay on Vajrayana Buddhist time, drawing implications for Fraser’s time typology. The essay will draw from English translations of significant older, tantric texts on dream yoga, deity yoga, the Chod, tantric time, the bardo of death, and empowerment. Useful practices that can be applied by the audience to test the tradition and author’s assertions will be suggested. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Journal of the History of Philosophy 41.2 (2003) 268-269 [Access article in PDF] A. A. Long. Epictetus: A Stoic and Socratic Guide to Life. New York: Oxford University Press, Clarendon Press, 2002. Pp. xiv + 310. Cloth, $29.95. Anthony Long's new book on Epictetus is a signal achievement for which scholars of Hellenistic philosophy, historians of intellectual culture, and thoughtful people generally ought to feel an enormous gratitude. And (...) here's why: Epictetus, a Greek philosopher (ca. 50-ca. 135 AD) in the Roman Empire, was popular in his own day and was influential with Marcus Aurelius as well as with Christian writers in the medieval period. Often cited and quoted, his influence perhaps reached an acme in the seventeenth and eighteenth centuries. His reputation languished in the nineteenth and most of the twentieth century. And even toward the end of the twentieth century—barring the interest of a handful of scholars—Epictetus was regarded primarily as a popularizer of Stoicism. Against this background Long's luminous study of Epictetus's philosophy can be measured, for what Long has done is to make us see that Epictetus is an important philosopher in his own right and not merely a popular purveyor of Stoic thought. He has done this by expounding three of the fundamental strands in Epictetus's thought. One is the immense role that Socrates plays in [End Page 268] Epictetus's teaching. The second is the unique character of Epictetus's teaching method—conversational and directly confrontational. And, thirdly, is the emphatic way in which Epictetus attempts to inculcate the Stoic doctrine that he found most congenial for the conduct of human life: that a human being's happiness and destiny is in his own power. For in his power and only in his power are those things alone which will secure him that happiness: his judgments and his desires. There is much else in Long's lucid account but by his emphasis on these themes and his inclusion of key passages he has translated from the Discourses he has with keen discernment brought to the world's attention both the cultural significance and the philosophical importance of this neglected philosopher. I now consider these themes in turn.In "the most creative appropriation of Socrates subsequent to the works of Plato and Xenophon" (94), Epictetus applies Socratic elenchus in his educational practice, for he uses it in conversational contexts to expose inconsistencies in students' preconceptions (regarding the desirability of goodness and the identity of goodness with the advantageous) and their judgments about the goodness or badness of some particular thing. In fact, part of Long's argument that Epictetus's discourses are wrongly construed as diatribes or sermons is that on analysis they can often be shown to be elenctic conversations in which the aim is to expose contradictions in a student's belief, say, that the happy life consists in the pursuit of what is advantageous and that running away from a dying daughter is an advantageous thing to do. More generally, the student is made to concentrate his attention on his preconceptions and motivations. While Long emphasizes the extent to which Epictetus, more than any other Stoic, appropriates Socratic elenchus in his educational methodology, he also, while directing attention to another aspect of that methodology, points out Epictetus's major departure from Socrates' use of elenchus. In Plato's Dialogues Socrates is always represented as engaged in conversations with others. Epictetus, by contrast, seems most bent on encouraging the student to engage in dialogue with himself, to try in an interior conversation with himself to bring to the surface of consciousness conflicts between his own moral preconceptions and motivations, on the one hand, and particular value judgments, on the other; and, in this way, to use the internal elenchus as his "principal instrument of moral progress" (86).Epictetus makes volition the central element in a human being's identity, character, and purpose. In the domain of volition are the only two things that are up to the individual—assents to impressions and... (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Contemporary IlluminationsReading Donne's "A Nocturnall upon S. Lucies Day through Three Twenty-First-Century PoemsTheresa M. DipasqualeIn his contribution to the 2017 volume John Donne and Contemporary Poetry, edited by Judith Scherer Herz, Jonathan F. S. Post explores "a nearly endless landscape of comparisons and contrasts" that unfolds between Stephen Edgar's 2008 poem "Nocturnal" and Donne's "A nocturnall upon S. Lucies day, Being the shortest day."1 Post's essay illuminates what Calvin (...) Bedient, in the same volume, calls the "great glacier-gloom" of Donne's "Nocturnall," its devastated "solemnity."2 In doing so, Post renders largely moot many questions that have preoccupied critics of Donne's poem: whether or how this poem reflects Donne's experience; whether the woman lamented by the speaker is a fiction or a historical person lamented by the poet; and if the latter, whether the poem mourns the 1617 death of John Donne's wife, Anne More Donne; the 1627 death of Donne's patroness Lucy, Countess of Bedford; or the Countess' near-fatal illness in 1612–13.3 These biographical and historical questions are not without value, but they draw the critic's attention away from more compelling questions regarding the "I" of the poem—a persona who claims not to be a person at all, but an inscription, a grave, "A quintessence" derived or "expresse[d]/... even from nothingnesse."4In this article, I widen and intensify the pool of light cast on Donne's "Nocturnall" by Post's presentist and intertextual analysis of Edgar's poem, examining three of the many other twenty-first-century poems that tap into Donne's poem, allude to it, quote it, adopt its structure, or respond to the anguish it expresses.5 Each of the three I discuss is [End Page 1] luminous in its own right but also a potent critical response to Donne's five-stanza poem. Each teaches something different about Donne's lyric. The poets whose work I consider—Liz Lochhead, Jay Wright, and Meena Alexander—all address twenty-first-century concerns; they grapple with questions and sorrows beyond the scope of Donne's conscious imagining yet latent in his poem. Each picks up where critics leave off when they "assume," as Alison R. Rieke notes, "that the speaker... is a husband or lover, possibly Donne, who experiences grief upon his wife's or mistress' death."6 Each takes up the challenge that Donne's persona issues when it denies that it is either "a man" (30) or any other living thing.In the first stanza of "A Nocturnall upon S. Lucies Day," this anti-persona observes that "all" other things around it are "Dead and enterr'd" and "yet" that "all these seeme to laugh, / Compar'd with mee, who am their Epitaph" (8–9). If it is an incised text rather than a human being, the poem's "mee" can no more speak than laugh; it is as silent as the grave it marks or as the dead flesh interred there. Indeed, it goes on to claim that it is "every dead thing" and that love's alchemical "art" has "expresse[d] / A quintessence even from" this mass of nonliving objects, this "nothingnesse" (12, 14–15). Struggling to define its anti-essential essence, it declares itself a mass burial site: "I, by loves limbecke, am the grave / Of all, that's nothing" (21–22). An epitaph, dead things, nothingness, a grave: all these are silent. And yet, in Donne's poem, they strenuously assert their nonbeing; they pulse with a paradoxically audible sense of self. After "Compar'd with mee" in the final line of the opening stanza, the reader encounters sixteen additional instances of the first-person singular in the poem's forty-five lines: "my" appears once, "mee" five times, and "I" eleven times. And the "I" issues a directive to readers: commanding, in the opening line of stanza 2, "Study me then, you who shall lovers bee" (10). But those who obey this order, making themselves students of the poem's inscribed nothingness, find themselves dismissed in the poem's final stanza. Having insisted that its "Sunne" will never "renew... (shrink)

The heart of this book is a dramatic love poem, the Rasa Lila, which is the ultimate focal point of one of the most treasured Sanskrit texts of India, the Bhagavata Purana. Judged a literary masterpiece by Indian and Western scholars alike, this work of poetic genius and soaring religious vision is one of the world's greatest sacred love stories and, as Graham Schweig clearly demonstrates, should be regarded as India's Song of Songs. The story presents the supreme deity as (...) the youthful and amorous cowherd, Krishna, who joins his beloved maidens in an enchanting and celebratory "dance of divine love." Schweig introduces this work of exquisite poetry and profound theology to the Western world in the form of a luminous translation and erudite scholarly treatment. His book explores the historical context and literary genre of the work and elucidates the aesthetic and emotional richness of the composition, highlighting poignant details of this drama of divine love. Schweig illuminates the religious dimensions and ethical nuances of the drama, drawing widely from the commentaries and esoteric vision of masters of the Caitanya school of Vaishnavism, a prominent devotional Hindu tradition. Themes such as transcendence of death through love, the yoga of devotion, the contrast between worldly love and passionate love for God, and the dialectical tension between ethical boundaries and boundless love are presented. The final event of the Rasa dance, the author concludes, presents a dynamic symbol of supreme love that provides the basis for a theological vision of genuine religious pluralism. (shrink)

Specular reflections and refractive distortions are complex image properties of solid transparent objects, but despite this complexity, we readily perceive the 3D shapes of these objects. We have found in past work that relevant sources of scene complexity have differential effects on 3D shape perception, with specular reflections increasing perceived thickness, and refractive distortions decreasing perceived thickness. In an object with both elements, such as glass, the two optical properties may complement each other to support reliable perception of 3D shape. (...) We investigated the relative dominance of specular reflection and refractive distortions in the perception of shape. Surprisingly, the ratio of specular reflection to refractive component was almost equal to that of ordinary glass and ice, which promote correct percepts of 3D shape. The results were also explained by the variance in local RMS contrast in stimulus images but may depend on overall luminance and contrast of the surrounding light field. (shrink)

The pupils of the eyes reflexively constrict in light and dilate in dark to optimize retinal illumination. Non-visual cognitive factors, like attention, arousal, decision-making, etc., also influence pupillary light response. During passive viewing, the eccentricity of a stimulus modulates the pupillary aperture size driven by spatially weighted corneal flux density, which is the product of luminance and the area of the stimulus. Whether the scope of attention also influences PLR remains unclear. In this study, we contrasted the pupil dynamics (...) between diffused and focused attentional conditions during decision-making, while the global CFD remained the same in the two conditions. A population of 20 healthy humans participated in a pair of forced choice tasks. They distributed attention to the peripheral decision cue in one task, and concentrated at the center in the other to select the target from four alternatives for gaze orientation. The location of this cue did not influence participants’ reaction time. However, the magnitude of constriction was significantly less in the task that warranted attention to be deployed at the center than on the periphery. We observed similar pupil dynamics when participants either elicited or canceled a saccadic eye movement, which ruled out pre-saccadic obligatory attentional orientation contributing to PLR. We further addressed how the location of attentional deployment might have influenced PLR. We simulated a biomechanical model of PLR with visual stimulation of different strengths as inputs corresponding to the two attentional conditions. In this homeomorphic model, the computational characteristic of each element was derived from the physiological and/or mechanical properties of the corresponding biological element. The simulation of this model successfully mimicked the observed data. In contrast to common belief that the global ambient luminosity drives pupillary response, the results of our study suggest that the effective CFD determined via the luminance multiplied by the size of the stimulus at the location of deployed attention in the visual space is critical for the magnitude of pupillary constriction. (shrink)

Defect detection is a major concern in quality control of various products in industries. This paper presents two different machine-vision based methods for detecting defects on periodically patterned textures. In the first method, input defective image is split into several blocks of size same as the size of the periodic unit of the image and chi-square histogram distances of each periodic block with respect to itself and all other periodic blocks are calculated to get a dissimilarity matrix. This dissimilarity matrix (...) is subjected to Ward's hierarchical clustering to automatically identify defective and defect-free blocks. The second method of defect detection is based on Universal Quality Index which is a measure of loss of correlation, luminance distortion and contrast distortion between any two signals. Quality indices of a periodic block with respect to itself and all other periodic blocks are calculated to get a similarity matrix containing quality indices. Specific variances of the periodic blocks are derived from the quality index matrix through orthogonal factor model based on eigen decomposition. These variances are subjected to Ward's hierarchical clustering to automatically identify defective and defect-free blocks. Results of experiments on real fabric images with defects show that the defect detection methods based on chi-square histogram distance and universal quality index yield a success rate of 98.6% and 97.8% respectively. (shrink)

In this paper I argue that one of the most important impulses that structure Hegel's account of religion is the need to show gratitude for the gift of creation. Beginning with the “Love“ fragment and 1805-6 Realphilosophie , I first explore what it means to see God's relationship to spirit as one of externalization or divestment ( Entäusserung ). Then, relying on the Berlin Lectures on the Philosophy of Religion, I argue that Hegel takes Christianity to be the Consummate Religion (...) because it not only offers its own divestment to match God's, but actually takes itself to participate in God's own divestment. This leads to a discussion of revealed religion in the Phenomenology , which, in contrast to simpler forms of religion such as the worship of luminous being ( Lichtwesen ), is able to conceive of a divine generativity in which spirit actively participates. I conclude by identifying two political implications of the centrality of divestment in Hegel's account. First, it means that, since Hegel takes Christianity to be unique in its representation of divine divestment, he cannot be a simple pluralist on religious truth. Second, Hegel's emphasis on divestment in his various accounts of religion helps set up his critique of sovereignty from the standpoint of philosophy or absolute knowing. While religion still clings to a vision of humanity as sovereign over nature, its origin in gratitude for creation proves to be incompatible with this vision. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Journal of the History of Philosophy 41.2 (2003) 268-269 [Access article in PDF] A. A. Long. Epictetus: A Stoic and Socratic Guide to Life. New York: Oxford University Press, Clarendon Press, 2002. Pp. xiv + 310. Cloth, $29.95. Anthony Long's new book on Epictetus is a signal achievement for which scholars of Hellenistic philosophy, historians of intellectual culture, and thoughtful people generally ought to feel an enormous gratitude. And (...) here's why: Epictetus, a Greek philosopher (ca. 50-ca. 135 AD) in the Roman Empire, was popular in his own day and was influential with Marcus Aurelius as well as with Christian writers in the medieval period. Often cited and quoted, his influence perhaps reached an acme in the seventeenth and eighteenth centuries. His reputation languished in the nineteenth and most of the twentieth century. And even toward the end of the twentieth century—barring the interest of a handful of scholars—Epictetus was regarded primarily as a popularizer of Stoicism. Against this background Long's luminous study of Epictetus's philosophy can be measured, for what Long has done is to make us see that Epictetus is an important philosopher in his own right and not merely a popular purveyor of Stoic thought. He has done this by expounding three of the fundamental strands in Epictetus's thought. One is the immense role that Socrates plays in [End Page 268] Epictetus's teaching. The second is the unique character of Epictetus's teaching method—conversational and directly confrontational. And, thirdly, is the emphatic way in which Epictetus attempts to inculcate the Stoic doctrine that he found most congenial for the conduct of human life: that a human being's happiness and destiny is in his own power. For in his power and only in his power are those things alone which will secure him that happiness: his judgments and his desires. There is much else in Long's lucid account but by his emphasis on these themes and his inclusion of key passages he has translated from the Discourses he has with keen discernment brought to the world's attention both the cultural significance and the philosophical importance of this neglected philosopher. I now consider these themes in turn.In "the most creative appropriation of Socrates subsequent to the works of Plato and Xenophon" (94), Epictetus applies Socratic elenchus in his educational practice, for he uses it in conversational contexts to expose inconsistencies in students' preconceptions (regarding the desirability of goodness and the identity of goodness with the advantageous) and their judgments about the goodness or badness of some particular thing. In fact, part of Long's argument that Epictetus's discourses are wrongly construed as diatribes or sermons is that on analysis they can often be shown to be elenctic conversations in which the aim is to expose contradictions in a student's belief, say, that the happy life consists in the pursuit of what is advantageous and that running away from a dying daughter is an advantageous thing to do. More generally, the student is made to concentrate his attention on his preconceptions and motivations. While Long emphasizes the extent to which Epictetus, more than any other Stoic, appropriates Socratic elenchus in his educational methodology, he also, while directing attention to another aspect of that methodology, points out Epictetus's major departure from Socrates' use of elenchus. In Plato's Dialogues Socrates is always represented as engaged in conversations with others. Epictetus, by contrast, seems most bent on encouraging the student to engage in dialogue with himself, to try in an interior conversation with himself to bring to the surface of consciousness conflicts between his own moral preconceptions and motivations, on the one hand, and particular value judgments, on the other; and, in this way, to use the internal elenchus as his "principal instrument of moral progress" (86).Epictetus makes volition the central element in a human being's identity, character, and purpose. In the domain of volition are the only two things that are up to the individual—assents to impressions and... (shrink)

Timothy Williamson has recently argued that few mental states are luminous , meaning that to be in that state is to be in a position to know that you are in the state. His argument rests on the plausible principle that beliefs only count as knowledge if they are safely true. That is, any belief that could easily have been false is not a piece of knowledge. I argue that the form of the safety rule Williamson uses is inappropriate, and (...) the correct safety rule might not conflict with luminosity. (shrink)

Using Finsler brane solutions [see details and methods in: S. Vacaru, Class. Quant. Grav. 28:215001, 2011], we show that neutrinos may surpass the speed of light in vacuum which can be explained by trapping effects from gravity theories on eight dimensional (co) tangent bundles on Lorentzian manifolds to spacetimes in general and special relativity. In nonholonomic variables, the bulk gravity is described by Finsler modifications depending on velocity/momentum coordinates. Possible super-luminal phenomena are determined by the width of locally anisotropic brane (...) (spacetime) and induced by generating functions and integration functions and constants in coefficients of metrics and nonlinear connections. We conclude that Finsler brane gravity trapping mechanism may explain neutrino super-luminal effects and almost preserve the paradigm of Einstein relativity as the standard one for particle physics and gravity. (shrink)

In this paper I argue that there is no viable alternative to construing our knowledge and justified belief as resting on a foundation restricted to truths about our internal states. Against Williamson and others I defend the claim that the internal life of a cognizer really does constitute a special sort of cognitive home that is importantly different from the rest of what we think we know and justifiably believe.