Written by the 11th-century Spanish Arab, Abh Muhammad ibn MucnOn Twilight and the Rising of Cloudsdh's value of around 52 miles remained standard until the 17th century, when it was revised sharply downward in consideration of atmospheric refraction and barometric studies. The treatise itself survives in a single Hebrew exemplar, 25 Latin exemplars, and an Italian exemplar derived from the Latin. At the heart of this present study is a critical text based on a fullscale comparative transcription of 22 of (...) the Latin manuscripts, ranging in date from the 13th to the 17th century. (shrink)

“Although up to now the [visual] image has been [understood as] a construct of reason,” Kepler observes in the fifth chapter of his Ad Vitellionem Paralipomena, “henceforth the [visible] representations of objects should be considered as paintings [ picturae ] that are actual[ly projected] on paper or some other screen.” While not intended as a historical generalization, this claim nonetheless reflects historical reality. Virtually all visual theorists before Kepler did, in fact, conceive of optical images as subjective, not objective constructs (...) – or, to put it in modern terms, as virtual rather than real entities. By current lights, of course, the distinction between virtual and real images is both obvious and common-place: whereas the latter can be physically projected upon a screen, the former cannot. (shrink)

In the first section I outline the theory of abstraction, discussing first its con- ceptual basis, then its psychological-epistemological basis, and last its causal basis. My purpose throughout is to show how these bases, and thus the theory itself, were not only paramountly Aristotelian, but also eminently sensible. In the second section I draw the perspectivist account of vision within the bounds of the theory of abstraction and show stage by stage how that account unfolds coherently within those bounds. This (...) procedure should make clear that what the perspecti- vists actually offered was less a scientific theory of light or vision than a scientifi- cally justified world view. (shrink)

One problem facing Hockney and Falco is the lack of evidence among optical sources to support their claim that artists used image-projection by the early 1400s. After all, if quattrocento artists knew about image-projection, they must have learned about it from experts in the field, and no one was more expert at the time than Perspectivist opticians. As I argue in this paper, however, Perspectivist reflection-analysis posed certain theoretical and conceptual constraints that would have prevented Perspectivist opticians from recognizing, much (...) less understanding, image-projection. Their silence on this matter is therefore not evidence against the Hockney-Falco thesis. (shrink)

From the late thirteenth to the early seventeenth century, the process of visual imaging was understood in the Latin West as an essentially subjective act initiated by the eye and completed by the brain. The crystalline lens took center stage in this act, its role determined by its peculiar physical and sensitive capacities. As a physical body, on the one hand, it was disposed to accept the physical impressions of light and color radiating to it from external objects. As a (...) sensitive body, on the other hand, it was enabled by the visual spirit flowing to it from the brain to feel those impressions visually. Acting as a sentient selector of visual information, the lens transformed the brute physical impressions of light and color into visual impressions. These, in turn, gave rise to perceptual “depictions” that were passed back along the stream of visual spirits to the brain. Known in Scholastic parlance as “intentional species,” these depictions served as virtual representations of their generating objects. As such, they provided the wherewithal not only for perception, but also for conception and cognition. (shrink)

That the medieval Latin version of Ibn al-Haytham's Kitāb al-Manā[zdotu]ir was translated into Italian in the fourteenth century has been known for well over a century. Recent studies have shown that this translation, which is contained in Vat. Lat. 4595, was instrumental in the composition of Lorenzo Ghiberti's Commentario terzo on art. Some eight years ago, the author of the present article tentatively identified the actual manuscript-source of that translation as MS Royal 12.G.7, which is currently held in the British (...) Library. This study establishes beyond reasonable doubt that his tentative identification was correct: MS Royal 12.G.7 is indeed the Latin source for the Italian translation in Vat. Lat. 4595. (shrink)

A. Mark Smith - Seeing and Being Seen in the Later Medieval World: Optics, Theology, and Religious Life - Journal of the History of Philosophy 44:3 Journal of the History of Philosophy 44.3 473-474 Dallas G. Denery, II. Seeing and Being Seen in the Later Medieval World: Optics, Theology, and Religious Life. Cambridge Studies in Medieval Life and Thought , 63. Cambridge-New York: Cambridge University Press, 2005. Pp. x + 202. Cloth, $75.00. Among the metaphors we live by , (...) visual metaphors figure prominently in our common discourse about cognition. We are well aware, of course, that in claiming to "see" meanings or "view" ideas in certain lights, we are speaking figuratively. Yet the analogy between thinking and seeing is more than a linguistic artifact. Until the seventeenth century,.. (shrink)

In the fifth book of his De aspectibus, the medieval Latin version of Ibn al-Haythamb al-Manir, Alhacen undertakes to determine precisely where a given ray of light will reflect to a given center of sight from a variety of convex and concave mirrors based on circular sections. As applied specifically to convex and concave spherical mirrors, this problem exercised several seventeenth-century thinkers, Christiaan Huygens foremost among them, and in that context it soon became known as Alhazens solution (or solutions) of (...) this problem is deficient in comparison to that of Huygens and later mathematicians. It is my purpose in this paper to show by reconstruction that in fact, far from deficient in any absolute sense, Alhacen’s approach to this problem was remarkably ingenious and elegant in its conceptual simplicity. (shrink)

Even given the final truths of what is right and wrong, good and bad, ethics is not complete. For one may yet ask “Why should I be moral?” Of course, we have no prior assurance that it will be possible to provide a non-moral and justifiable answer to the rational and self-interested person. Nevertheless, I claim that reasons for being moral can be provided even for the rational, self-interested, and remorseless individual who knows he will not be caught. In defending (...) my claim I will draw on empirical data from recent social psychology and game theory. Actual human selves are malleable in a number of ways. I will show that it is rational for the self-interested person to modify selves in such a way that moral actions are increasingly preferred. Specifically, I will argue that it is in one’s rational self-interest to enhance empathy in others and future selves in such a way that for increasing numbers other-injury becomes a component of self-injury, and other-benefit becomes a component of self-benefit. This will allow a linkage to be drawn from rational and self-interested action to moral action. The development of this theory will begin by distinguishing my approach from that of Gauthier, then three interpretations of the “Why be moral?” question will be delineated, next the decision theoretic components of my account will be presented, and finally the role of empathy will be considered in detail. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Reviewed by:Seeing and Being Seen in the Later Medieval World: Optics, Theology, and Religious LifeA. Mark SmithDallas G. Denery, II. Seeing and Being Seen in the Later Medieval World: Optics, Theology, and Religious Life. Cambridge Studies in Medieval Life and Thought (Fourth Series), 63. Cambridge-New York: Cambridge University Press, 2005. Pp. x + 202. Cloth, $75.00.Among the metaphors we live by (to borrow from Lakoff and Johnson), visual (...) metaphors figure prominently in our common discourse about cognition. We are well aware, of course, that in claiming to "see" meanings or "view" ideas in certain lights, we are speaking figuratively. Yet the analogy between thinking and seeing is more than a linguistic artifact. Until the seventeenth century, Western thinkers took it seriously, none more seriously perhaps than the thirteenth-century scholastic community. The upshot was an epistemology based on two cardinal assumptions: first, that the physical world manifests itself to us through species passing from external objects into the soul, and second, that visual perception is providentially designed to yield a faithful conceptual picture of physical reality and its ordering structure.This latter assumption found strong support in Perspectivist optics, which took mature form in the 1260s as an amalgam of Alhacenian visual analysis and species-theory. Hence, by the later thirteenth century it was widely believed not only that vision is essentially cognitive but also that cognition is essentially visual. During the first half of the fourteenth century, this idea was subjected to trenchant criticism and thereby rejected out of hand by several thinkers, among whom Nicolaus of Autrecourt is a particular subject of emphasis in this study.It has become something of a truism lately that theories are neither accepted nor rejected on logical grounds alone. This one, Denery claims, is no exception since there were compelling theological grounds for its adoption. Foremost among these was a new emphasis on self-presentation in the thirteenth century. That emphasis manifested itself at two levels. On the one hand, the clerical orders were encouraged to give the right appearance and to suit the appearance to specific settings. This was especially important among the new preaching orders, whose members had to put on so many public faces that they came to adopt what Denery calls "heuristics of adaptation." On the other hand, new modes of confession and penance required deep introspection on the penitent's part, so that he might "see" himself for the complex of sinful motives and actions he is, as well as experience the contrition-yielding horror such a sight arouses. In both cases, the appearances should reveal the underlying reality: the preacher's spiritual commitment reflected in his mien, the penitent's contrition in the recognition of his vitiated nature.But how can we be sure that what we see in these instances is true? This question is particularly vexing in the case of religious introspection, for, as St. Paul reminds us, our moral vision is distorted by the mirror that darkens it. Enter the analogy between physical vision and cognition. Visual illusions, such as those arising from reflection, were of paramount concern to Perspectivist theorists, who devoted considerable effort to rationalizing them according to unmet normative conditions, such as adequate illumination, appropriate distance, or a healthy eye. Reflected vision is subject to transgressions of these conditions, but adding insult to their injury is that, when seen in mirrors, objects invariably appear displaced and often look distorted in size, shape, and orientation. Fortunately, reason enables us to rectify such illusions according to specific rules that govern visual perception in general and reflection in particular.If the analogy between physical and moral vision holds true, then reason ought to be the corrective in both cases. At first blush, this seems to be Peter of Limoges's position in the Tractatus moralis de oculo (c. 1280), but, as Denery insists, Peter's real point is that our inner, moral vision is so clouded we can rarely tell either how or even that it is distorted. The hoped-for normative circumstances and principles enabling us to rectify it are far too vague and protean to yield certainty from introspection. Given the tight conceptual linkage between... (shrink)

ABSTRACTIt is proposed that experts are able to integrate prior contextual knowledge with emergent visual information to make complex predictive judgments about the world around them, often under heightened levels of uncertainty and extreme time constraints. However, limited knowledge exists about the impact of anxiety on the use of such contextual priors when forming our decisions. We provide a novel insight into the combined impact of contextual priors and anxiety on anticipation in soccer. Altogether, 12 expert soccer players were required (...) to predict the actions of an oncoming opponent while viewing life-sized video simulations of 2-versus-2 defensive scenarios. Performance effectiveness and processing efficiency were measured under four conditions: no contextual priors about the action tendencies of the opponent and low anxiety ; no CP and high anxiety ; CP and LA; CP and HA. The provision of contextual priors did not affect processing efficiency, but it improved performance effectiveness... (shrink)

A decade ago, we reviewed the field of clinical ethics; assessed its progress in research, education, and ethics committees and consultation; and made predictions about the future of the field. In this article, we revisit clinical ethics to examine our earlier observations, highlight key developments, and discuss remaining challenges for clinical ethics, including the need to develop a global perspective on clinical ethics problems.

In De Anima II.6, Aristotle divides the objects of perception into three kinds: “special perceptibles" (idia aisthêta) such as colours, sounds and flavours, which can be perceived in their own right by only one sense; “common perceptibles" (koina aisthêta) such as shapes, sizes and movements, which can be perceived in their own right by multiple senses; and “incidental perceptibles,” such as the son of Diares, which can be perceived only “incidentally” (kata sumbebêkos). In this paper, I examine this division of (...) perceptibles and consider what it amounts to. First, I argue that Aristotle’s distinction between perceiving something in its own right (kath' hauto) and perceiving it incidentally marks a causal distinction: what is perceived in its own right causes perception as such, whereas what is perceived incidentally coincides with what is perceived in its own right. Second, I argue that for Aristotle special perceptibles, unlike common perceptibles, belong to homogeneous bodies on account of their chemical composition. Finally, I explain the primacy Aristotle assigns to special perceptibles and his claim that perception of them alone is free from error. I conclude with some brief remarks on Aristotle and the primary/secondary quality distinction. (shrink)

The early withdrawal of students from healthcare education programmes, particularly nursing, is an international concern and, despite considerable investment, retention rates have remained stagnant. Here, a regional study of healthcare student retention is used as an example to frame the challenge of student attrition using a concept from policy development, wicked problem theory. This approach allows the consideration of student attrition as a complex problem derived from the interactions of many interrelated factors, avoiding the pitfalls of small‐scale interventions and over‐simplistic (...) assumptions of cause and effect. A conceptual framework is proposed to provide an approach to developing actions to reduce recurrent investment in interventions that have previously proved ineffective at large scale. We discuss how improvements could be achieved through integrated stakeholder involvement and acceptance of the wicked nature of attrition as a complex and ongoing problem. (shrink)

Weak emergence is the view that a system’s macro properties can be explained by its micro properties but only in an especially complicated way. This paper explains a version of weak emergence based on the notion of explanatory incompressibility and “crawling the causal web.” Then it examines three reasons why weak emergence might be thought to be just in the mind. The first reason is based on contrasting mere epistemological emergence with a form of ontological emergence that involves irreducible downward (...) causation. The second reason is based on the idea that attributions of emergence are always a reflection of our ignorance of non-emergent explanations. The third reason is based on the charge that complex explanations are anthropocentric. Rather than being just in the mind, weak emergence is seen to involve a distinctive kind of complex, macro-pattern in the mind-independent objective micro-causal structure that exists in nature. The paper ends by addressing two further questions. One concerns whether weak emergence applies only or mainly to computer simulations and computational systems. The other concerns the respect in which weak emergence is dynamic rather than static. (shrink)