The term “perceptual constancy” was used by the Gestalt theorists in the early part of the twentieth century (e.g., Koffka 1935, 34, 90) to refer to the tendency of perception to remain invariant over changes of viewing distance, viewing angle, and conditions of illumination. This tendency toward constancy is remarkable: every change in the viewing distance, position, and illumination is necessarily accompanied by a change in the local proximal (retinal) stimulation, and yet perception remains relatively stable. The tendency toward perceptual (...) constancy encouraged the Gestalt theorists to look beyond local proximal stimulation in grounding their theories of perception. In the ensuing decades, much has been learned about the constancies. Evidence for this assertion may be found in the contributions to the current volume as well as in earlier volumes (e.g., Epstein 1977; Walsh and Kulikowsky 1998). These advances notwithstanding, significant questions remain open. Our aim here is to note some advances and specify some open questions. (shrink)

We examine a number of investigations of perceptual economy or, more specifically, of minimum tendencies and minimum principles in the visual perception of form, depth, and motion. A minimum tendency is a psychophysical finding that perception tends toward simplicity, as measured in accordance with a specified metric. A minimum principle is a theoretical construct imputed to the visual system to explain minimum tendencies. After examining a number of studies of perceptual economy, we embark on a systematic analysis of this notion. (...) We examine the notion that simple perceptual representations must be defined within the "geometric constraints" provided by proximal stimulation. We then take up metrics of simplicity. Any study of perceptual economy must use a metric of simplicity; the choice of metric may be seen as a matter of convention, or it may have deep theoretical and empirical implications. We evaluate several answers to the question of why the visual system might favor economical representations. Finally, we examine several accounts of the process for achieving perceptual economy, concluding that those which favor massively parallel processing are the most plausible. (shrink)

This article seeks the origin, in the theories of Ibn al-Haytham (Alhazen), Descartes, and Berkeley, of two-stage theories of spatial perception, which hold that visual perception involves both an immediate representation of the proximal stimulus in a two-dimensional ‘‘sensory core’’ and also a subsequent perception of the three dimensional world. The works of Ibn al-Haytham, Descartes, and Berkeley already frame the major theoretical options that guided visual theory into the twentieth century. The field of visual perception was the first area (...) of what we now call psychology to apply mathematics, through geometrical models as used by Euclid, Ptolemy, Ibn al-Haytham, and Descartes (among others). The article shows that Kepler’s discovery of the retinal image, which revolutionized visual anatomy and entailed fundamental changes in visual physiology, did not alter the basic structure of theories of spatial vision. These changes in visual physiology are advanced especially in Descartes' Dioptrics and his L'Homme. Berkeley develops a radically empirist theory vision, according to which visual perception of depth is learned through associative processes that rely on the sense of touch. But Descartes and Berkeley share the assertion that there is a two-dimensional sensory core that is in principle available to consciousness. They also share the observation that we don't usually perceived this core, but find depth and distance to be phenomenally immediate, a point they struggle to accommodate theoretically. If our interpretation is correct, it was not a change in the theory of the psychology of vision that engendered the idea of a sensory core, but rather the introduction of the theory into a new metaphysical context. (shrink)

'Tis true governments cannot be supported without great charge, and it is fit everyone who enjoys a share of the protection should pay out of his estate his proportion for the maintenance of it. But still it must be with his own consent, i.e., the consent of the majority giving it either by themselves or their representatives chosen by them. For if any one shall claim a power to lay and levy taxes on the people, by his own authority, and (...) without such consent of the people, he thereby invades the fundamental law of property and subverts the end of government. For what property have I in that which another may by right take when he pleases to himself. (shrink)

Shape and slant judgments of rotated or frontoparallel ellipses were elicited from three groups of 10 subjects. A masking stimulus was introduced to control processing time. Backward masking trials were presented with interstimulus intervals of 0, 25, and 50 msec, Reduction of processing time altered shape judgments in the direction of projective shape and slant judgments in the direction of frontoparallelness. This finding is consistent with the shape-slant invariance hypothesis. In order to study the effects of processing load, one group (...) of subjects was given prior knowledge of the kind of judgment to be made on each trial, one group had no prior knowledge, and a third group made both judgments on each trial. The effects of the processing load manipulation were interpreted in terms of the role of attention in perceptual encoding. Consistent with previous findings, allocation of attention did not affect perceptual encoding. (shrink)

Twelve subjects provided shape and orientation judgments for a set of projectively equivalent, variously rotated rectangles under three viewing conditions—monoptic, dichoptic, and binocular—with and without the presence of a pattern mask. In the absence of the mask, partial constancy was exhibited under the first two conditions and near perfect constancy under the binocular condition. Orientation was discriminated. Presence of the mask produced projective shape matching and diminished orientation discrimination. It is argued that the site of masking was postchiasmal, and the (...) results are related to previous work with pattern masking of projectively equivalent ellipses. (shrink)

Background Traditional top-down national regulation of internationally mobile doctors and nurses is fast being rendered obsolete by the speed of globalisation and digitisation. Here we propose a bottom-up system in which responsibility for hiring and accrediting overseas staff begins to be shared by medical employers, managers, and insurers. Discussion In this model, professional Boards would retain authority for disciplinary proceedings in response to local complaints, but would lose their present power of veto over foreign practitioners recruited by employers who have (...) independently evaluated and approved such candidates' ability. Evaluations of this kind could be facilitated by globally accessible National Registers of professional work and conduct. A decentralised system of this kind could also dispense with time-consuming national oversight of continuing professional education and license revalidation, which tasks could be replaced over time by tighter institutional audit supported by stronger powers to terminate underperforming employees. Summary Market forces based on the reputation (and, hence, financial and political viability) of employers and institutions could continue to ensure patient safety in the future, while at the same time improving both national system efficiency and international professional mobility. (shrink)

This book presents modern logic as the formalization of reasoning that needs and deserves a semantic foundation. Chapters on propositional logic; parsing propositions; and meaning, truth and reference give the reader a basis for establishing criteria that can be used to judge formalizations of ordinary language arguments. Over 120 worked examples illustrate the scope and limitations of modern logic, as analyzed in chapters on identity, quantifiers, descriptive names, and functions. The chapter on second-order logic shows how different conceptions of predicates (...) and propositions do not lead to a common basis for quantification over predicates, as they do for quantification over things. Notable for its clarity of presentation and supplemented by many exercises, this volume will be invaluable for philosophers, linguists, mathematicians, and computer scientists who wish to better understand the tools they use in formal reasoning. (shrink)

With this book, Richard A. Epstein provides a spirited and systematic defense of classical liberalism against the critiques mounted against it over the past thirty years. One of the most distinguished and provocative legal scholars writing today, Epstein here explains his controversial ideas in what will quickly come to be considered one of his cornerstone works. He begins by laying out his own vision of the key principles of classical liberalism: respect for the autonomy of the individual, (...) a strong system of private property rights, the voluntary exchange of labor and possessions, and prohibitions against force or fraud. Nonetheless, he not only recognizes but insists that state coercion is crucial to safeguarding these principles of private ordering and supplying the social infrastructure on which they depend. Within this framework, Epstein then shows why limited government is much to be preferred over the modern interventionist welfare state. Many of the modern attacks on the classical liberal system seek to undermine the moral, conceptual, cognitive, and psychological foundations on which it rests. Epstein rises to this challenge by carefully rebutting each of these objections in turn. For instance, Epstein demonstrates how our inability to judge the preferences of others means we should respect their liberty of choice regarding their own lives. And he points out the flaws in behavioral economic arguments which, overlooking strong evolutionary pressures, claim that individual preferences are unstable and that people are unable to adopt rational means to achieve their own ends. Freedom, Epstein ultimately shows, depends upon a skepticism that rightly shuns making judgments about what is best for individuals, but that also avoids the relativistic trap that all judgments about our political institutions have equal worth. A brilliant defense of classical liberalism, Skepticism and Freedom will rightly be seen as an intellectual landmark. (shrink)

Imitation is said to be the sincerest form of flattery. Socially, the proposition may well be true. But in the world of ideas it is false: to the extent that two incompatible traditions use the same words or symbols to articulate different visions of legal or social organization, imitation begets confusion, not enlightenment. The effects of that confusion, moreover, are not confined to the world of ideas, but spill over into the world of politics and public affairs. Words are more (...) than tools of description: they work also as tools of persuasion and transformation. Let a term have a favorable connotation in one context, and its imitative use can mislead people into thinking that a major departure from established practice is merely the extension or updating of an old principle to deal with new circumstances. (shrink)

In this paper, I want to explore the relationship between the various forms of individual self-interest and the appropriate structures of government. I shall begin with the former, and by degrees extend the analysis to the latter. I do so in order to mount a defense of principles of limited government, private property, and individual liberty. The ordinary analysis of self-interest treats it as though it were not only a given but also a constant of human nature, and thus makes (...) few allowances for differences between persons. Yet common experience tells us that personality and behavior are as unique as fingerprints. The positive inquiry, therefore, is how we find what is constant about self-interest in a world of natural human diversity. The normative inquiry must take into account both the constant and variable features of human nature in order to determine what forms of social arrangements hold the greatest prospect of long-term social advantage. The gulf between ‘is’ and ‘ought’ must be overcome here, as it must be in all normative discourse. Yet we cannot make sensible judgments of what ought to be the case in the domain of rules unless we first have some idea of what is the case in the domain of behavior. The initial inquiry asks why self-interest is regarded as a constant of human behavior. The explanation derives more from the biological and less from the social. The powerful pressures of natural selection weed out any organisms for whom selfinterest is not the paramount consideration. (shrink)

The Gestalt psychologists adopted a set of positions on mind-body issues that seem like an odd mix. They sought to combine a version of naturalism and physiological reductionism with an insistence on the reality of the phenomenal and the attribution of meanings to objects as natural characteristics. After reviewing basic positions in contemporary philosophy of mind, we examine the Gestalt position, characterizing it m terms of phenomenal realism and programmatic reductionism. We then distinguish Gestalt philosophy of mind from instrumentalism and (...) computational functionalism, and examine Gestalt attributions of meaning and value to perceived objects. Finally, we consider a metatheoretical moral from Gestalt theory, which commends the search for commensurate description of mental phenomena and their physiological counterparts. (shrink)

In a backward masking paradigm Epstein, Hatfield, and Muise (1977) found that presentation of a frontoparallel pattern mask caused the perceived shape of elliptical figures which were rotated in depth to conform to a projective shape function. The current study extended the masking function by examining the effect of a mask which was partially or wholly cotemporal with the target. The study also assessed the functional equivalence of the masking treatment and the conventional treatment for minimizing depth information. Reports (...) of perceived shape and perceived orientation were obtained under three conditions: binocular without mask, binocular with mask, monocular without mask. Under the first condition, perceived shape conformed to objective shape and perceived orientation was proportional to objective orientation. Under the latter two conditions, perceived shape was in very close agreement to projective shape and the two functions did not differ. Orientation was underestimated greatly under both conditions. We concluded that the effect of the mask on perceived shape is mediated by its effect on encoding of orientation information, although an additional effect on the subsequent stage of shape-slant integration cannot be excluded. (shrink)

Errata slip inserted. Bibliography: p. 137-140.

The contributions in the book examine the historical and contemporary manifestations of organized crime, the symbiotic relationship between legitimate and ...

This book grew out of my confusion. If logic is objective how can there be so many logics? Is there one right logic, or many right ones? Is there some underlying unity that connects them? What is the significance of the mathematical theorems about logic which I've learned if they have no connection to our everyday reasoning? The answers I propose revolve around the perception that what one pays attention to in reasoning determines which logic is appropriate. The act of (...) abstracting from our reasoning in our usual language is the stepping stone from reasoned argument to logic. We cannot take this step alone, for we reason together: logic is reasoning which has some objective value. For you to understand my answers, or perhaps better, conjectures, I have retraced my steps: from the concrete to the abstract, from examples, to general theory, to further confirming examples, to reflections on the significance of the work. (shrink)

Using the case of an industrial accident involving a killer robot, the author successfully combines technical and ethical concepts to present to students and professionals real-life issues that they may one day have to confront.

MOTIVATION The constructivization of ; => D(_£^') poses several problems. For some of these the tools of MD can be modified; for others new methods will need to be established. What must we do to make a full approximation to ; * D? We ...

Without question, the libertarian vision that envisions the use of state power to control force and fraud as a proper governmental function is one piece of any comprehensive political theory. But the hard-line libertarian goes astray in finding this the sole function of government or in thinking that the maintenance of order is possible without the imposition of taxes. Rather, the case for taxation rests on the familiar view that state coercion is sometimes necessary to overcome coordination problems. The justification (...) for a minimal system of taxation therefore is that it provides more in benefits for the individuals taxed than they lose in revenue. Stressing the benefit shows the mistake in Nozick’s famous observation that taxation is “on a par” with forced labor. And the proper understanding of the logic of taxation shows the defects in the series of steps in demoktesis—or “ownership of the people, by the people, and for the people”—that Nozick offers to show how difficult it is to draw any clear line between taxation and slavery. (shrink)

The critical literary world has spent a wealth of thought and words on the question of Hawthorne himself: Where does he stand in his works? In history? In literary tradition? In this major new study, G. R. Thompson recasts the "Hawthorne question" to show how authorial presence in the writer's works is as much a matter of art as the writing itself. The Hawthorne who emerges from this masterful analysis is not, as has been supposed, identical to the provincial narrator (...) of his early tales; instead he is revealed to be the skillful manipulator of that narrative voice, an author at an ironic distance from the tales he tells. By focusing on the provincial tales as they were originally conceived--as a narrative cycle--Thompson is able to recover intertextual references that reveal Hawthorne's preoccupation with framing strategies and variations on authorial presence. The author shows how Hawthorne deliberately constructs sentimental narratives, only to deconstruct them. Thompson's analysis provides a new aesthetic context for understanding the whole shape of Hawthorne's career as well as the narrative, ethical, and historical issues within individual works. Revisionary in its view of one of America's greatest authors, The Art of Authorial Presence also offers invaluable insight into the problems of narratology and historiography, ethics and psychology, romanticism and idealism, and the cultural myths of America. (shrink)

A number of fairness issues and principles are developed and discussed from the context of personnel selection. It is noted that not too much attention has been paid to these issues and concerns in the past. A distinction is made between justice and fairness having to do with the procedural components and processes of selection, the nature of the information used to make selection decisions, and the resulting outcomes of the selection process. Ideas for future research and exploration are also (...) extended. (shrink)

The country's leading libertarian scholar sets forth the essential principles for a legal system that best balances individual liberty versus the common good.

The inequalities of wealth and fortune form a central part of the human condition, and these over time have been a constant source of social unease. Whether they should be praised and preserved or endured or corrected is an issue that produces uniform discord. One source of this difficulty in analysis stems from the possible ways in which these persistent inequalities arise. It is easy to condemn any differences in wealth created by the victor's expropriation of the vanquished's honest toil. (...) It is far more difficult to condemn those identical differences when they are attributable to the thrift and foresight of the successful relative to the laziness or self-destructiveness of the impoverished. Furthermore, most find it morally ambiguous how best to respond to differences between persons that are the result of luck or chance, such that they do not reflect positively or negatively on either the character of those who have done well or those who have done poorly. (shrink)

This research examines the association between attitudes on cheating and cognitive moral development. In this research, we use Rest's (1979a) Defining Issues Test, the Attitudes on Honesty Scale (Authors) and Academic Integrity Index (Authors); the last two are adaptations of the DIT. A total of 220 students from three universities participated in the study (66 psychology majors and 154 business majors). The data indicate that 66.4 percent of the students reported that they cheated in high school, college, or both high (...) school and college. Psychology majors scored higher than business majors on both the Defining Issues Test (Rest, 1979a) and the Attitudes on Honesty Scale (AHS, Authors). Using factor analysis, we found significant associations between students' ratings of the importance considerations present in the three cheating scenarios and their estimates of whether cheating would occur (i.e., the Academic Integrity Index). Finally, using logistic regression, we found that the scores on the Attitudes on Honesty Scale and Academic Integrity Index associate with the self-reported cheating behavior of college students. (shrink)

Although death by neurologic criteria is legally recognized throughout the United States, state laws and clinical practice vary concerning three key issues: the medical standards used to determine death by neurologic criteria, management of family objections before determination of death by neurologic criteria, and management of religious objections to declaration of death by neurologic criteria. The American Academy of Neurology and other medical stakeholder organizations involved in the determination of death by neurologic criteria have undertaken concerted action to address variation (...) in clinical practice in order to ensure the integrity of brain death determination. To complement this effort, state policymakers must revise legislation on the use of neurologic criteria to declare death. We review the legal history and current laws regarding neurologic criteria to declare death and offer proposed revisions to the Uniform Determination of Death Act and the rationale for these recommendations. (shrink)