Traditional explanations of multistable visual phenomena (e.g. ambiguous figures, perceptual rivalry) suggest that the basis for spontaneous reversals in perception lies in antagonistic connectivity within the visual system. In this review, we suggest an alternative, albeit speculative, explanation for visual multistability – that spontaneous alternations reflect responses to active, programmed events initiated by brain areas that integrate sensory and non-sensory information to coordinate a diversity of behaviors. Much evidence suggests that perceptual reversals are themselves more closely related to the expression (...) of a behavior than to passive sensory responses: (1) they are initiated spontaneously, often voluntarily, and are influenced by subjective variables such as attention and mood; (2) the alternation process is greatly facilitated with practice and compromised by lesions in non-visual cortical areas; (3) the alternation process has temporal dynamics similar to those of spontaneously initiated behaviors; (4) functional imaging reveals that brain areas associated with a variety of cognitive behaviors are specifically activated when vision becomes unstable. In this scheme, reorganizations of activity throughout the visual cortex, concurrent with perceptual reversals, are initiated by higher, largely non-sensory brain centers. Such direct intervention in the processing of the sensory input by brain structures associated with planning and motor programming might serve an important role in perceptual organization, particularly in aspects related to selective attention. (shrink)

Both individually and as a collection, these essays will promote understanding and provoke further debate amongst students and established scholars alike.

Correspondence should be addressed to David A. Leopold [email protected] the viewing of certain patterns, widely known as ambiguous or puzzle figures, perception lapses into a sequence of spontaneous alternations, switching every few seconds between two or more visual interpretations of the stimulus. Although their nature and origin remain topics of debate, these stochastic switches are generally thought to be the automatic and inevitable consequence of viewing a pattern without a unique solution. We report here that in humans such perceptual alternations (...) can be slowed, and even brought to a standstill, if the visual stimulus is periodically removed from view. We also show, with a visual illusion, that this stabilizing effect hinges on perceptual disappearance rather than on actual removal of the stimulus. These findings indicate that uninterrupted subjective perception of an ambiguous pattern is required for the initiation of the brain-state changes underlying multistable vision.Visual perception involves coordination between sensory sampling of the world and active interpretation of the sensory data. Human perception of objects and scenes is normally stable and robust, but it falters when one is presented with patterns that are inherently ambiguous or contradictory. Under such conditions, vision lapses into a chain of continually alternating percepts, whereby a viable visual interpretation dominates for a few seconds and is then replaced by a rival interpretation. This multistable vision, or 'multistability', is thought to result from destabilization of fundamental visual mechanisms, and has offered valuable insights into how sensory patterns are actively organized and interpreted in the brain1, 2. Despite a great deal of recent research and interest in multistable perception, however, its neurophysiological underpinnings remain poorly understood. Physiological studies have suggested that disambiguation of ambiguous patterns. (shrink)

The Young Karl Marx is an innovative and important new study of Marx’s early writings. These writings provide the fascinating spectacle of a powerful and imaginative intellect wrestling with complex and significant issues, but they also present formidable interpretative obstacles to modern readers. David Leopold shows how an understanding of their intellectual and cultural context can illuminate the political dimension of these works. An erudite yet accessible discussion of Marx’s influences and targets frames the author’s critical engagement with Marx’s account (...) of the emergence, character, and (future) replacement of the modern state. This combination of historical and analytical approaches results in a sympathetic, but not uncritical, exploration of such fundamental themes as alienation, citizenship, community, antisemitism, and utopianism. The Young Karl Marx is a scholarly and original work which provides a radical and persuasive reinterpretation of Marx’s complex and often misunderstood views of German philosophy, modern politics, and human flourishing. (shrink)

Facial appearance changes with age and health affecting skin color as well as facial and head hair. Yet somehow the brain is able to see past shared structure and dynamic deformations to focus on subtle details that distinguish one face from another. This article argues that the brain takes an efficient approach to this problem using prior knowledge about the structure of faces in its analysis. It employs intrinsic norms to focus on subtle variations in the shared face configuration that (...) differentiate one face from another. The study reviews evidence that the brain uses multiple norms to extract face identity that these norms are shaped by visual experience, and that norm-based coding is well-suited to meeting the challenges of image-based face perception mentioned above. By encoding faces with reference to stored perceptual norms the visual system can focus on what is unique to each individual, allowing for the discrimination of thousands of faces despite their similarity. (shrink)

“utopophobia” is a diverse and long-established phenomenon. Recent discussion of the notion of “realism” in political philosophy has illuminated one form that the fear of utopia can take—namely, suspicion and disapproval of normative standards that are unlikely ever to be achieved—but has not exhausted all that is of interest here.1 The present paper is concerned with a different variety of utopophobia: namely, the historically influential but not well-understood hostility of Karl Marx and Friedrich Engels toward the provision of plans and (...) blueprints of the ideal society of the future.2There seems little doubt about the existence of this Marxian utopophobia. (Note that I use the.. (shrink)

Leopold first discusses the conservation of natural resources in the southwestern United States in economic tenns, stressing, in particular, erosion and aridity. He then concludes his analysis with a discussion of the moral issues involved, developing his general position within the context of P. D. Ouspenky’s early philosophy of organism.

Understanding how activity in the brain leads to a subjective percept is of great interest to philosophers and neuroscientists alike. In the last years, neurophysiological experiments have approached this problem directly by measuring neural signals in animals as they experience well-defined visual percepts. Stimuli in these studies are often inherently ambiguous, and thus rely upon the subjective report, generally from trained monkeys, to provide a measure of perception. By correlating activity levels in the brain to this report, one can speculate (...) on the role of individual neurons and groups of neurons in the formation and maintenance of a particular percept. However, in order to draw valid conclusions from such experiments, it is critical that the responses accurately and reliably reflect what is perceived. For this reason, a number of behavioural paradigms have been developed to control and evaluate the truthfulness of responses from behaving animals. Here we describe several approaches to optimizing the reliability of a monkey's perceptual report, and argue that their combination provides an invaluable approach in the study of subjective visual perception. (shrink)

Leopold first discusses the conservation of natural resources in the southwestern United States in economic tenns, stressing, in particular, erosion and aridity. He then concludes his analysis with a discussion of the moral issues involved, developing his general position within the context of P. D. Ouspenky’s early philosophy of organism.

Over the past decades, anti-cancer treatments have evolved rapidly from cytotoxic chemotherapies to targeted therapies including oral targeted medications and injectable immunooncology and cell therapies. New anti-cancer medications come to markets at increasingly high prices, and health insurance coverage is crucial for patient access to these therapies. State laws are intended to facilitate insurance coverage of anti-cancer therapies.Using Massachusetts as a case study, we identified five current cancer coverage state laws and interviewed experts on their perceptions of the relevance of (...) the laws and how well they meet the current needs of cancer care given rapid changes in therapies. Interviewees emphasized that cancer therapies, as compared to many other therapeutic areas, are unique because insurance legislation targets their coverage. They identified the oral chemotherapy parity law as contributing to increasing treatment costs in commercial insurance. For commercial insurers, coverage mandates combined with the realities of new cancer medications — including high prices and often limited evidence of efficacy at approval — compound a difficult situation. Respondents recommended policy approaches to address this challenging coverage environment, including the implementation of closed formularies, the use of cost-effectiveness studies to guide coverage decisions, and the application of value-based pricing concepts. Given the evolution of cancer therapeutics, it may be time to evaluate the benefits and challenges of cancer coverage mandates. (shrink)

Background: Continuous viewing of ambiguous patterns is characterized by wavering perception that alternates between two or more equally valid visual solutions. However, when such patterns are viewed intermittently, either by repetitive presentation or by periodic closing of the eyes, perception can become locked or "frozen" in one configuration for several minutes at a time. One aspect of this stabilization is the possible existence of a perceptual memory that persists during periods in which the ambiguous stimulus is absent. Here, we use (...) a novel paradgim of temporally interleaved ambiguous stimuli to explore the nature of this memory, with particular regard to its potential impact on perceptual organization. Results: We found that the persistence of a perceptual configuration was robust to interposed visual patterns and, further, that at least three ambiguous patterns, when interleaved in time, could undergo parallel, stable time courses. Then, using an interleaved presentation paradigm, we established that the occasional reversal in one pattern could be coupled with that of its interleaved counterpart, and that this coupling was a function of the structural similarity between the patterns. Conclusions: We postulate that the stabilization observed with repetitive presentation of ambiguous patterns can be at least partially accounted for by processes that retain a recent perceptual interpretation, and we speculate that such memory may be important in natural vision. We further propose tha the interleaved paradigm introduced here may be of great value to gauge aspects of stimulus similarity that appeal to particular mechanisms of perceptual organization. (shrink)

Bruno Bauer (1809–1882) is neither a well known nor an easily accessible author.1 Despite playing a significant role in both the evolution of Hegelianism and in nineteenth century controversies abo...

This chapter discusses the account of ideology found in the writings of Karl Marx, and its fate in the subsequent Marxist tradition. Marx understood ideology as consisting of certain social ideas which periodically dominate in class-divided societies. More precisely, ideology was characterized as having a particular epistemological standing, social origin, and class function. In the subsequent Marxist tradition that ‘critical’ account was often displaced by non-critical, predominately ‘descriptive’, accounts of ideology. This historical pattern is exemplified by the writings of Antonio (...) Gramsci and Louis Althusser. This displacement of critical by descriptive accounts is portrayed as regrettable, not least because it involves a loss of the explanatory purchase and emancipatory potential found in Marx’s original account. (shrink)

INTRODUCTION It is a commonplace to observe that the left-Hegelian Max Stirner is little-known.gure in the history of political and philosophical thought. However, that obscurity should not be exaggerated. The author of Der Einzige und sein Eigentum is not only familiar to certain rather specialised and largely academic circles-those with an interest in Hegelianism, for example, or in the early intellectual development of Karl Marx -he is also, and more widely, known as a member of, and in.uence upon, the anarchist (...) tradition. Stirner's best-known work is often excerpted in anthologies of anarchist writings, and his name is regularly included as part of the modern pantheon in historically orientated surveys of anarchist thought. (shrink)

[Although research in wildlife management is repeating the history of agriculture, unlike agricultural research, which employs scientific means for economic ends, the ends of wildlife research are judged in terms of aesthetic satisfactions as governed by “good taste.” Wild animals and plants are economically valuable only in the sense that human performers and works of art are: the means are of the brain, but the ends are of the heart. Wildlife management has forged ahead of agriculture in recognizing the invisible (...) interdependencies in the biotic community. Moreover, it has admitted its inability to replace natural equilibria and its unwillingness to do so even if it could. Because many animals do not exhibit their natural behavior under laboratory conditions, researchers are dependent on observation in the wild. The difficulties involved in isolating variables are especially clear in the study of the natural cycle. It is a problem which seems to defy the experimental method.]. (shrink)

Gathers the pre-Sand Country Almanac writings of Aldo Leopold, showing that he was not born an ecologist, but evolved over time through experimentation and thought.

This paper reviews the main pricing policies in Latin American countries, discussing their shortcomings. It also gives an overview of the most common pricing and reimbursement policies in Europe and describes in detail three well-established approaches — international price referencing, value-based pricing, including setting up of health technology assessment, and generic and biosimilar policies — building on country examples.

Gareth Stedman Jones has written a scholarly and interesting biography of Karl Marx, framed by the plausible idea that the ‘authentic’ Marx needs to be recovered from layers of 20th-century misinterpretation. The book focuses more on the political context than the intellectual content of Marx's ideas, and its treatment of the latter has some limitations. Not least, the author underestimates the complexity, interest, and relevance, of certain elements of Marx's thought.

There had been interesting interactions between philosophical reflections, technical developments and the work of artists, poets and designers, starting especially in the 1950s and 1960s with a stimulating cell in Stuttgart and Ulm in Germany spreading mutual international interactions. The paper aims to describe the philosophical background of Max Bense with his research on the intellectual history of mathematics and the upcoming studies on technology and cybernetics. Together with communication theories and semiotics, new aesthetics such as cybernetic aesthetics had been (...) worked out, based on the notions of information and sign. This background stimulated international students, artists and researchers from different creative disciplines for methodical approaches leading to first computer art experiments. The interrelations in these fields with Latin America are in the focus of these studies. Students, artists, and poets from Latin America, especially Brazil, came to Germany for studies and exhibitions in the creative scientific cell around Max Bense. Some of them stayed in Europe, but the exchange developed also in the opposite direction, traveling to and working in Latin America. Some of those fruitful international interrelations will be described and reflected. (shrink)