A quarter of a century ago, the first systematic behavioral experiments were performed to clarify the nature of color constancy—the effect whereby the perceived color of a surface remains constant despite changes in the spectrum of the illumination. At about the same time, new models of color constancy appeared, along with physiological data on cortical mechanisms and photographic colorimetric measurements of natural scenes. Since then, as this review shows, there have been many advances. The theoretical requirements for constancy have been (...) better delineated and the range of experimental techniques has been greatly expanded; novel invariant properties of images and a variety of neural mechanisms have been identified; and increasing recognition has been given to the relevance of natural surfaces and scenes as laboratory stimuli. Even so, there remain many theoretical and experimental challenges, not least to develop an account of color constancy that goes beyond deterministic and relatively simple laboratory stimuli and instead deals with the intrinsically variable nature of surfaces and illuminations present in the natural world. (shrink)

For a stable visual world, the colours of objects should appear the same under different lights. This property of colour constancy has been assumed to be fundamental to vision, and many experimental attempts have been made to quantify it. I contend here, however, that the usual methods of measurement are either too coarse or concentrate not on colour constancy itself, but on other, complementary aspects of scene perception. Whether colour constancy exists other than in nominal terms remains unclear.

Naive observers viewed a sequence of colored Mondrian patterns, simulated on a color monitor. Each pattern was presented twice in succession, first under one daylight illuminant with a correlated color temperature of either 16,000 or 4,000 K and then under the other, to test for color constancy. The observers compared the central square of the pattern across illuminants, either rating it for sameness of material appearance or sameness of hue and saturation or judging an objective property—that is, whether its change (...) of color originated from a change in material or only from a change in illumination. Average color constancy indices were high for material appearance ratings and binary judgments of origin and low for hue–saturation ratings. Individuals’ performance varied, but judgments of material and of hue and saturation remained demarcated. Observers seem able to separate phenomenal percepts from their ontological projections of mental appearance onto physical phenomena; thus, even when a chromatic change alters perceived hue and saturation, observers can reliably infer the cause, the constancy of the underlying surface spectral reflectance. (shrink)

On its twenty-fifth anniversary, Fides et ratio remains relevant for its bold defense of reason and the complementarity of faith and reason. It describes a philosophy that is not the preserve of academics but the duty of every person. It asserts that philosophy is never contained in one system but is always open to new questions and further insights. St. John Paul defends a philosophy that welcomes pluralism based on the richness of being but rejects a pluralism based on the (...) impossibility of knowing the truth. Reflecting on Fides et ratio, this article describes six ways that theology uses philosophy and offers five lessons for philosophers, i.e., the universal character of philosophy, the complementarity of faith and reason, the necessity and limits of pluralism, the requirements for a philosophy to be consonant with theology, and the current reinvigoration of philosophy in seminaries. (shrink)

Small changes in daylight in the environment can produce large changes in reflected light, even over short intervals of time. Do these changes limit the visual recognition of surfaces by their colour? To address this question, information-theoretic methods were used to estimate computationally the maximum number of surfaces in a sample that can be identified as the same after an interval. Scene data were taken from successive hyperspectral radiance images. With no illumination change, the average number of surfaces distinguishable by (...) colour was of the order of 10,000. But with an illumination change, the average number still identifiable declined rapidly with change duration. In one condition, the number after two minutes was around 600, after 10 min around 200, and after an hour around 70. These limits on identification are much lower than with spectral changes in daylight. No recoding of the colour signal is likely to recover surface identity lost in this uncertain environment. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:AQUINAS ON THE IMMATERIALITY OF THE INTELLECT DAVID RUEL FOSTER Seton Hall University South Orange, New Jersey I. A Controversial Question? HE QUESTION of the immateriailiity of the intelloot s,an important part of the wider question about the nau11e of the soul. The axgiumen'ts for the immaiteriality of rthe intellect a11e particularly important to Thomas's thought because they undergil1d his argument for the incorruptibility of the soul; the incorruptibiility (...) of the soul, in turn, leads towards the dootrine of the immortaility of the soruJ, a tenet of faith which Thoma.s wants to explain and deifend.1 This article will present Thomas's two most prominent arguments for the immateriality of the intieliteot and critique the first iin light of rthe seoond.2 Whether,the principle of int~Uectual ilife must, by the very 1.Arguments for the immateriality of the intellect do not necessarily appear in articles on the incorruptibility of the soul but are always presupposed by them in Thomas. For example, in Summa theologiae I, q. 75, a. 6, "Whether the human soul is incorruptible?" (" Utrum anima humana sit corruptibilis "), Thomas supports the crucial premise in his argument by referring to the,arguments for the immateriality of the intellect in articles 2 and 5 (" Utrum anima humana sit aliquid subsistens? "; "Utrum anima sit composita ex materia et forma?" Summa theologiae I, q. 75, aa. 2 and 5). 2 Five important instances of the arguments are as follows: In Sententias II, d. 19, q. 1, a. l; Summa contra gentiles II, chapters 49-50; Summa theologiae I, q. 75, aa. 2 and 5; Quaestiones Dis-putatae De anima a. 14; Oompendium theologiae, De fide, chapters 79 and 84. This chronological ordering is based on Weisheipl's catalogue in Friar Thomas D'A.quino, pp. 355-406; and Eschmann's, A Catalogue of St. Thomas's Work, in Gilson's, The Christian Philosophy of St. Thomas Aquinas, pp. 381-439. The dating of the Compendium theologiae is the most problematic. 415 416 DAVID RUEL FOSTER natUJ.1e of its.act, be immaterial is a particularly controrverted question today. Many corutempo~ary thinkers helie¥e that human understanding can be ex:pfained in strictly physical terms. ':Chis was not the case in Thomas's day, and it is important to takie notre of this. Thomas W1as noit foroed by any opponent to sharpen his arguments for the imma.teriality of the inteHect. The major Islamic philosophers, ailithough they disagreed among themselves about aspects of the inbe1iJiect's nature (e.g., the plaice and ro[e of the agent intellect)' md agree thait the intellectual soul was immaterial. Plato and Aristotle, according.to Thomas, agreed on this f.undamental point. In fact, although there were post-Socratic materialists,3 Thoma;s usuru1Jy goes ha;ek to the Pre-Socratics in order rto give an example of someone who taJUght that the inte!IJiectual :act. depends entirely on physicrul principles. Perhaps it is better to s1ay that, because the doctrine of runiversal hylomorphism was so widely accepted in his time, Thomas was not challenged regarding the incorporeality of the intellect. Many of Thoma:s's contemporaries, foililowing the tewching of Awoobroin, held that the intellectuaJ. souil was composed of spiritua.l matter.and the appropriate form,4 hut this was not in opposition to Thomas's arguments for the immateriality of the intellect. II. The Two Most Prominent Arguments A. Type I The first argument (hereaf·ter caUed Type 1) proceeds from the intellect's potential to know all corporeal things. It is justifiably described as Thomas's preferred argument,5 for s For example, the Epicureans. 4 J. Weisheipl, "Albertus Magnus and Universal Hylomorphism: Avicebron," in Albert the priam rationem formalem, which is :to grasp the essence of the obj,oot. Then Thom!lis draws his conclusion " therefore,... the inte!llecrbuaJ soul itse[f is an absolute form." The conclusion that the irntellect's mode of being is immaterial, a " form without matter," follows from the premises: majorr premise, the objeclt is,in the knower in an ahso1uite way, i.e., without matter; minor premise, the object is received in the knower.ruooording to rthe mode of he... (shrink)

This book is a collection of secondary essays on America's most important philosophic thinkers—statesmen, judges, writers, educators, and activists—from the colonial period to the present. Each essay is a comprehensive introduction to the thought of a noted American on the fundamental meaning of the American regime.

The aim of this study was to test red - green dichromats' ability to discriminate between illuminant and surface-reflectance changes in natural scenes. Stimuli were simulations of natural scenes presented on a colour monitor with 10-bit resolution per gun. The natural scenes were obtained with a fast hyperspectral imaging system. Six different scenes (including rocks, foliage, and buildings) were tested. In each trial, two images were presented in sequence, each for 1 s, with no interval. The images differed in the (...) phase of daylight on the scene: first with correlated colour temperature 25 000 K, then 6 700 K. The spectral reflectance of a region in the second image was changed randomly, consistent with a local change in daylight. The observer's task was to decide whether a particular surface in the successive images was the same (pure illuminant change) or different (illuminant change with a surface-reflectance change). The performance of four deuteranopes and five protanopes varied considerably across the scenes tested, with mean colour constancy indices (± 1 SEM) of 0.48 (± 0.13) and 0.19 (± 0.10), respectively (1.0 representing ideal performance). Deuteranopes seemed less disadvantaged than protanopes, performing close to normal with some scenes. (shrink)

The aims of this dissertation are to categorize, clarify, and assess Thomas' arguments for the immateriality of the intellect. ;The five principal texts are: Scriptum super Libros Sententiarum II, d.19, q.1, a.1; Summa Contra Gentiles II, Chapters 49 and 50; Summa Theologiae I, q.75, aa.2, 5; Quaestiones Disputatae De anima, a.14; and Compendium Theologiae, Chapters 79 and 84. ;Of the thirty-six arguments for the immateriality of the intellect surveyed, thirty of them can be collected under five basic types. Type 1 (...) argues that since the intellect is in potency to know all sensible things it must not be composed of any sensible thing. Type 2--the intellect's grasp of the universal transcends the limits of matter and therefore it could not be composed of matter. Type 3--since knowing involves the unity of knower and known, impossible consequence follow if the intellect were material. Type 4--if the intellect were a material organ then it could not know itself as it does. Type 5--while contraries cannot exist together in a body, they do exist together in the intellect. ;Although some new arguments are introduced and others are dropped, types 1 and 2 remain the primary arguments throughout Thomas' career. Type 1 is preferred by Thomas, but it is actually type 2 that is most pervasive. The expression of type 2 varies more than that of type 1; type 2 is often combined with elements of other arguments, an indication of its fundamental character among these arguments. I argue that type 2 is the most fundamental argument for the immateriality of the intellect, and is most promising for use in the present day. ;Type 1 is an incomplete rendering of Aristotle and is inconsistent with Thomas' own description of the internal sense powers. Insofar as one fortifies type 1 by pointing to the different way the intellect has its object , one is actually using type 2 to maintain type 1. Furthermore, type 1 does not allow a proper assimilation of modern findings about brain function, and finally, it does a disservice to the unity of the person. (shrink)

Polanyi’s and Tillich’s unique dialogue of February 1963 is systematically exegeted, its provenance and aftermath traced and its disappointing but challenging outcome inventoried. Mutual lack of preparation flawed the Berkeley meeting along with Tillich’s severe preoccupation. Polanyi had valued Tillich’s basic theology but never delved into the latter’s important conceptualization of science, wherein Polanyi’s own concerns are significantly broached. Tillich had barely heard of Polanyi, while under the surface was widedisparity in the meaning of faith. Afterwards, having meaninglessly blandished, they (...) ignored each other, though the late Tillich espoused freedom in faith in a way that would have opened him to Polanyi’s help and the latter desiderated a panentheistic endorsement of human creativity as part of his Pauline envisagement of satisfying and open ended faith— which was just what Tillich became intent upon in the denoument of his system. Destined lovers who tragically fail to connect, they leave their respective societies with a truly proactive heritage, since the cultural crisis they combatted has if anything worsened. (shrink)

Polanyi’s and Tillich’s unique dialogue of February 1963 is systematically exegeted, its provenance and aftermath traced and its disappointing but challenging outcome inventoried. Mutual lack of preparation flawed the Berkeley meeting along with Tillich’s severe preoccupation. Polanyi had valued Tillich’s basic theology but never delved into the latter’s important conceptualization of science, wherein Polanyi’s own concerns are significantly broached. Tillich had barely heard of Polanyi, while under the surface was widedisparity in the meaning of faith. Afterwards, having meaninglessly blandished, they (...) ignored each other, though the late Tillich espoused freedom in faith in a way that would have opened him to Polanyi’s help and the latter desiderated a panentheistic endorsement of human creativity as part of his Pauline envisagement of satisfying and open ended faith— which was just what Tillich became intent upon in the denoument of his system. Destined lovers who tragically fail to connect, they leave their respective societies with a truly proactive heritage, since the cultural crisis they combatted has if anything worsened. (shrink)

Richard Connell’s book brings together Aristotle’s great metaphysical insight, that everything has four causes, with the discoveries of modern natural science. Whereas many contemporary philosophers and natural scientists think the question of the nature and number of causes is irrelevant or resolved, Connell thinks that they are indispensable distinctions that have been mauled beyond recognition.

Shepard's analysis of how shape, motion, and color are perceptually represented can be generalized. Apparent motion and shape may be associated with a group of spatial transformations, accounting for rigid and plastic motion, and perceived object color may be associated with a group of illuminant transformations, accounting for the discriminability of surface-reflectance changes and illuminant changes beyond daylight. The phenomenological and mathematical parallels between these perceptual domains may indicate common organizational rules, rather than specific ecological adaptations. [Barlow; Hecht; Kubovy & (...) Epstein; Schwartz; Shepard; Todorovic]. (shrink)

. John V. Apczynski, while presenting a helpful analysis of Wolfhart Pannenberg and Michael Polanyi, does not succeed in showing that Pannenberg’s theology is incoherent. Contrary to Apczynski, I hold that Pannenberg’s concern for theoretic assertions is not extrinsic but intrinsic and central to his program. Moreover, this concern does not rest directly upon the cultural dominance of impersonal knowing but is a countering of the theological overreaction against it. Polanyi has pioneered the critique of impersonal knowledge, but in Pannenberg’s (...) judgment much theology tends to espouse too cheaply the Polanyian elevation of faith as ground of knowing. Pannenberg, while appreciating the relative justification of Polanyi’s work, is attempting to thematize afresh—in interesting contrast to Polanyi and, for instance, Paul Tillich—the public, rational structure of faith. (shrink)

As psychology ethics begins to become more standardized and formalized globally (e.g., Gauthier, 2007) there are still educational, political, and psychological areas that require significant discussion. For example, test security has become a global issue, as psychological tests and even college entrance and graduate school admission tests have found their way online.

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Queer Ricans: Cultures and Sexualities in the DiasporaDavid William Foster (bio)Lawrence La Fountain-Stokes. Queer Ricans: Cultures and Sexualities in the Diaspora. Minneapolis: U of Minnesota P, 2009. xxvii + 242 pp.Is "queer" a particularly relevant denomination for Puerto Rican cultural production because of the deep and abiding contradictions of Puerto Rican society, which swings back and forth between two dominant parties (statehood vs. commonwealth status), but with a (...) firm imaginary in a party that cannot seem to win elections (independence)? Or is it because of the peculiar relationship it has with the U.S. mainland, which hardly prizes its Spanish-speaking heritage and its quality as a nation of people of color? Or is it simply because, as Puerto Ricans profit from the dynamics of queer American society they only seem to exist in greater abundance than in Argentina, Mexico, Colombia, Brazil? Can the influence of American feminism account for the appreciable concentration of Puerto Rican lesbians? Does the possibility of unrestricted residence in the United States. mainland enhance access to a wider array of movement politics, performance spaces, publications venues, and university and other institutional positions than would be possible in Puerto Rico or in any other Latin American society? Finally, does the stateside training of so many outstanding Puerto Rican scholars like Lawrence La Fountain-Stokes simply mean that there is a larger pool of critical voices to register, analyze, and—yes—promote Puerto Rican queers? Certainly, whatever the other reasons, it was the availability of the latter that allowed us to give a particularly prominent representation of Puerto Ricans in the 1994 Latin American Writers on Gay and Lesbian Themes: A Bio-Critical Sourcebook.Let me underscore from the outset that La Fountain-Stokes's point of reference is the extensive representation of Puerto Rican queers in American society, a large majority of whom write in English, work with U.S.-based institutions, and publish in English-language and U.S.-based forums. While some may move back and forth between the mainland and the island and publish in Spanish outside the mainland (in Puerto Rico or elsewhere), the emphasis of his study is on Puerto Rican queers in the U.S. Indeed, as La Fountain-Stokes articulates at the outset of his study, his purpose is to overcome the elision of sexuality in examinations of mainland-island patterns of migration [End Page 66] and to "transform Puerto Rican migration studies paradigms by showing how attitudes toward stigmatized forms of same-sex sexuality and gender variance provoke and affect migration, and how artists, writers, filmmakers, dancers, choreographers, and performers have documented and discussed this fact" (ix).La Fountain-Stokes, who is himself a highly accomplished queer Puerto Rican writer and a scholar with well-established credentials in the field, makes use of a range of three theoretical perspectives in organizing this study: (1) the sociohistorical question of migratory patterns between the U.S. mainland and the island of Puerto Rico, a question that has mostly been cast in political and economic terms, but which the author insists must be revised in terms of an inventory of sexualities and sexual identities that are exercised and performed in terms of the differences between life in one or another locale and, one might add, in terms of the experience of life in the United States in differing locales; (2) the question of theorizing sexuality, particularly the axis/continuum between heterosexual and nonheterosexual and the continuum between different and differing instantiations of the nonheterosexual, but primarily between gay and queer; and (3) theoretical postulates relating to queerness that may or may not intersect and collide with matters of national and/or ethnic identity. The very phrase "queer [Puerto] Ricans" is structurally ambiguous: are we talking about Puerto Ricans who are queer (as opposed to Puerto Ricans who are not queer, a restrictive qualification), or are we talking about all Puerto Ricans, one of whose characteristics is that they are queer, an extensive qualification)? La Fountain-Stokes's inventory of analysis makes clear that the former is the basic emphasis of his research, but the actual performative content of many of the examples of cultural production he... (shrink)

This discussion, featuring short comments by R. Melvin Keiser, Durwood Foster, Richard Gelwick and Donald Musser, grew out of articles in TAD 35:3 (2008-2009) on connections and disconnections between the thought of Polanyi and Tillich (featuring essays by Foster and Gelwick with a response from Musser). Keiser raises questions about perspectives articulated in the earlier articles and Foster, Gelwick and Musser respond here.

An important factor in judging whether two retinal images arise from the same object viewed from different positions may be the presence of certain properties or cues that are 'qualitative invariants' with respect to the natural transformations, particularly affine transformations, associated with changes in viewpoint. To test whether observers use certain affine qualitative cues such as concavity, convexity, collinearity, and parallelism of the image elements, a 'same-different' discrimination experiment was carried out with planar patterns that were defined by four points (...) either connected by straight line segments (line patterns) or marked by dots (dot patterns). The first three points of each pattern were generated randomly; the fourth point fell on their diagonal bisector. According to the position of that point, the patterns were concave, triangular (three points being collinear), convex, or parallel sided. In a 'same' trial, an affine transformation was applied to one of two identical patterns; in a 'different' trial, the affine transformation was applied after the point lying on the diagonal bisector was perturbed a short, fixed distance along the bisector, inwards for one pattern and outwards for the other. Observers' ability to discriminate 'same' from 'different' pairs of patterns depended strongly on the position of the fourth, displaced, point: performance varied rapidly when the position of the displaced point was such that the patterns were nearly triangular or nearly parallel sided, consistent with observers using the hypothesised qualitative cues. The experimental data were fitted with a simple probabilistic model of discrimination performance that used a combination of these qualitative cues and a single quantitative cue. (shrink)

The number of discriminable colours is often assumed to be of the order of several million but the extent of detectable chromatic diversity present in individual natural scenes is an open question. Here, the aim was to estimate the number of discriminable colours seen in natural scenes. Hyperspectral data were obtained from a set of natural scenes over the range 400 - 720 nm at 10 nm intervals (Nascimento et al, 2002 Journal of the Optical Society of America A 19 (...) 1484 - 1490) and the representation of each scene in CIELAB space computed for all pixels of the image. The number of discriminable colours was estimated by counting the number of unit volumes in the three-dimensional volume defined by the scene when represented in CIELAB space. We found that the number of discriminable colours estimated in a scene could vary by an order of magnitude from scene to scene, but rarely exceeded 105, indicating a limited chromatic diversity. (shrink)

Colour constancy refers to the ability to extract information about surface colours independently of illumination conditions. A ripe strawberry, for example, appears the same red when viewed under a blue sky or a reddish sunset. Since Land's pioneering work, discussion has centred on the issue whether colour constancy is achieved primarily in the retina or visual cortex. Recently, the debate has shifted to a consideration of the constraints imposed by various psychophysical tasks and instructions. Humans can judge illuminant colour, reflected-light (...) colour, surface colour, and the relationship between surface colours within a scene. Such observations suggest that colour constancy may not be a unitary phenomenon, and that its different aspects may be mediated at different levels in the visual system. Several questions therefore arise: are the tasks of surface estimation and illuminant estimation complementary, insofar as good performance in one implies poor performance in the other? How does retinal adaptation alter performance? Is colour vision tuned to the statistical composition of natural surfaces and illuminants? What role does colour-opponent processing in retina and cortex play in colour constancy? These and related questions are explored here in order to better understand what we mean when we ask: "Why do strawberries look red?". (shrink)

A series of experiments was performed in which subjects indicated whether two four-dot patterns were the same, although possibly viewed from different directions, or different, paired at random. Analyses of responses times and error rates suggest that the subjects' performance in this affine matching task is based on non-accidental properties such as convexity, parallelism, collinearity, and proximity, rather than on real affine invariants such as the ratio of triangular areas.

Galgan wants to write a biography of being, and the character witnesses are Aristotle, Anselm, Descartes, and Feuerbach. The main points are that Anselm is a pivot between a classical and modern view of God in first philosophy, and that modern philosophers gave up the search for God by claiming to have found God to be man. Thus God was replaced by subjectivity--our subjectivity. The book is not a textual study, but does give a fairly close commentary on texts of (...) Anselm, Descartes, and Feuerbach. (shrink)

R. J. Henle, one of the few philosophers to have a village named after him, has published the fruit of his twenty-plus years of teaching epistemology. The book is intended to be both a textbook and a contribution to philosophical literature.

The most striking feature of Leo Elders’s book is the broad context with which he surrounds Thomas’s doctrine of nature. For example, his discussion of the soul provides a good review of the doctrine before and after Thomas, his discussion of “time” takes us from Parmenides to Einstein. Because Elders wants to refute those who think the doctrine of Thomas is simply of historical interest, he consistently relates Thomas’s teaching to the contemporary state of the question. He does a credible (...) job of discussing everything from general field theory, to quarks, to cell biology. (shrink)