Newborn bloodspot screening programs are some of the longest running population screening programs internationally. Debate continues regarding the need for parents to give consent to having their child screened. Little attention has been paid to how meanings of consent-related terminology vary among stakeholders and the implications of this for practice. We undertook semi-structured interviews with parents, healthcare professionals and policy decision makers in two Canadian provinces. Conceptions of consent-related terms revolved around seven factors within two broad domains, decision-making and information (...) attainment. Decision-making comprised: parent decision authority; voluntariness; parent engagement with decision-making; and the process of enacting choice. Information ascertainment comprised: professional responsibilities ; parent responsibilities; and the need for discussion and understanding prior to a decision. Our findings indicate that consent-related terms are variously understood, with substantive implications for practice. We suggest that consent procedures should be explained descriptively, regardless of approach, so there are clear indications of what is expected of parents and healthcare professionals. Support systems are required both to meet the educational needs of parents and families and to support healthcare professionals in delivering information in a manner in keeping with parent needs. (shrink)

Several recent systematic and targeted reviews have highlighted limitations in our understanding of talent in sport. However, a comprehensive profile of where the scientific research has focused would help identify gaps in current knowledge. Our goal in this scoping review was to better understand what others have done in the field of research, to summarize the constituent areas of research in a meaningful way, to help identify gaps in the research, and to encourage future research to address these gaps. Peer-reviewed (...) articles written in English that met several inclusion criteria were analyzed. A total of 1,899 articles were identified, and the descriptive findings revealed a relatively narrow focus of research on talent in sport. Specifically, the majority of examined articles focused on males only, the sport of soccer, perceptual cognitive variables, developing athletes, adult samples, and cross-sectional designs. For better or worse, the concept of talent remains a central element of how coaches, practitioners, and scientists think about athlete development. Findings from this scoping review highlight the continued need to explore issues related to talent identification, selection, and development in more diverse samples and contexts. There is also a clear necessity to focus on under-researched areas using alternative methodologies. (shrink)

Working parents in are struggling to balance the demands of their occupation with those of childcare and homeschooling during the COVID-19 pandemic. Moreover, studies show that women are shouldering more of the burden and reporting greater levels of psychological distress, anxiety, and depression relative to men. However, research has yet to show that increases in psychological symptoms are linked to changes in stress during the pandemic. Herein, we conduct a small-N study to explore the associations between stress and psychological symptoms (...) during the pandemic among mothers using structural equation modeling, namely latent change score models. Thirty-three mothers completed questionnaires reporting current anxious and depressive symptoms, as well as stressful life experiences prior to-versus during the pandemic. Women endorsed significantly more stressful events during the pandemic, relative to the pre-pandemic period. Additionally, 58% of mothers scored as moderate-to-high risk for developing a stress-related physical illness in the near future because of their pandemic-level stress. Depressive symptoms were associated with the degree of change in life stress, whereas anxiety symptoms were more related to pre-pandemic levels of stress. The present study preliminarily sheds light on the nuanced antecedents to mothers’ experiences of anxious and depressive symptoms during the COVID-19 pandemic. Although further work is needed in larger, more diverse samples of mothers, this study highlights the potential need for appropriate policies, and prevention and intervention programs to ameliorate the effects of pandemics on mothers’ mental health. (shrink)

In _Selected Writings on Race and Difference_, editors Paul Gilroy and Ruth Wilson Gilmore gather more than twenty essays by Stuart Hall that highlight his extensive and groundbreaking engagement with race, representation, identity, difference, and diaspora. Spanning the whole of his career, this collection includes classic theoretical essays such as “The Whites of Their Eyes” (1981) and “Race, the Floating Signifier” (1997). It also features public lectures, political articles, and popular pieces that circulated in periodicals and newspapers, which (...) demonstrate the breadth and depth of Hall's contribution to public discourses of race. Foregrounding how and why the analysis of race and difference should be concrete and not merely descriptive, this collection gives organizers and students of social theory ways to approach the interconnections of race with culture and consciousness, state and society, policing and freedom. (shrink)

John Stuart Mill underwent a mental crisis in the 1820s. He emerged from it, argues Fred Wilson, with a new understanding of the notion of introspective analysis more dequare as an empirical method than the sort of analysis that had been used by earlier utilitarian thinkiers such as Bentham and James Mill. Wilson's study places Mill's innovations in the context of earlier work in ethics and perception and of subsequent developments in the history of psychology. He shows (...) the significance of these topics with which Mill was concerned. The more adequate notion of introspective analysis enabled the younger Mill to reply to criticisms of various empiricist and utilitarian positions cencering the analysis of relations, the nature of our percievings of physical objects, the status of science of economics, and the nature of the utilitarian principle itself. Mill was thus able to reject the quantitative hedonism of his predecessors and to introduce qualitative hedonism in its place. Wilson suggest that the long tradition that views Mill's qualitative hedonism as inconsistent is mistaken, as area a variety of criticisms of his work in the psychology of perception and the philosophy of economics. A better grasp of the background of Mill's views of psychology and the philosophy of psychology easily shows the critics to be mistaken. (shrink)

John Stuart Mill proposed that all policy precepts, be they in the areas of morality or prudence or aesthetics, are all subordinate to the precepts of the Art of Life. The value which he assumes in defining the Art of Life is the Principle of Utility. This principle, being normative rather than fact, can admit of no proof based solely on deductive inference. Yet Mill proposed considerations that he believed capable of rationally persuading one to accept his principle as (...) the basic principle for the Art of Life. This paper aims to evaluate this argument. In particular, it tries to show that a crucial step, often thought to be a logical howler, is not to be so simply dismissed. It is shown that if one accepts certain theses from Mill's philosophy of science and of social science, concerning the composition of causes, then the crucial step is fully justified. It is also suggested that these theses of Mill's philosophy of science are mistaken. So Mill's proof of utility is, after all, unsound, but the reconstruction proposed shows it to be much more plausible and much more philosophically interesting than is often thought. (shrink)

This book examines the various norms for the logic and methodology of science, placing them in the context of the cognitive interests and explanatory ideals that motivate science. Various themes in the philosophy of science are examined, including the views of K. Popper, T. Kuhn, and L. Laudan. Characteristic cases of scientific theories are examined in order to illustrate and justify the proposed norms. These include, on the one hand, the emergence of the science of Galileo, Kepler, and Newton from (...) the older metaphysical style of explanation to be found in Aristotle and, on the other hand, Darwin's theory of natural selection. Also included are characteristic cases of pseudoscience, including creation science, Lysenkoism, Velikovsky, UFOs and ancient astronauts, astrology, parapsychology, and various kinds of alternative medicine. From these examples and the more theoretical discussion, there emerges a series of norms for demarcating science and pseudoscience. Various aspects of the scientific method are examined in detail, including the role of hypotheses, the logical structure of theories, and how these relate to the experimental methods of John Stuart Mill. collection; for example, what do we say about observational reports of the existence of UFOs? In this context there is a discussion of some of the issues raised in the so-called science wars. It is concluded that the sociology of science can at times be helpful to the scientific community in improving their methods of investigation. (shrink)

This is a book that challenges the current orthodoxy, both in the philosophy of mind and in the cognitive sciences, that thinking (construed broadly to include perceiving, imagining, remembering, etc.) is a mental process in the head. Such a view has been largely taken for granted since the demise of behaviorism in the 1960s, and it underpins both the representational and computational theories of mind, including their connectionist and dynamicist variants. While the orthodoxy has been rejected in recent years by (...) a motley collection of e-theorists—externalists, embodiers, embedders, and extended minders—Melser’s view is quite distinct from such views. For Melser, rather than thinking being a process that begins in the head but extends beyond it (as most e-theorists hold), it is a personal-level activity, something that a person does through her actions. Since Melser views such activities as being disjoint from natural processes, thinking is not a natural process at all, the sort of thing that we might study scientifically. Thus, thinking is a personal action that calls for a different kind of study, one that draws on empathy, interpretation, and hermeneutics. That is the view defended at the core of the book (chh.1-7), and if it makes it sound like a very old-fashioned book, that’s because it is. Melser’s antecedents are philosophers such as Gilbert Ryle, J.L. Austin, and Stuart Hampshire, both in style and in content. Apart from Melser’s heavy reliance on selective parts of developmental psychology, there is minimal discussion of substantive work in contemporary cognitive science. That is what might be expected from an author whose view is that whatever it is cognitive scientists are doing, it is not (much to their surprise, no doubt) the investigation of thinking. As I will try to show in a moment, however, the central argument of the book could have been strengthened by more direct engagement with such empirical work. (shrink)

How are non-declarative sentences understood? How do they differ semantically from their declarative counterparts? Answers to these questions once made direct appeal to the notion of illocutionary force. When they proved unsatisfactory, the fault was diagnosed as a failure to distinguish properly between mood and force. For some years now, efforts have been under way to develop a satisfactory account of the semantics of mood. In this paper, we consider the current achievements and future prospects of the mood-based semantic programme.

In this book, Stuart Hampshire argues that no individual and no modern society can avoid conflicts between incompatible moral interests.

We might think that thought experiments are at their most powerful or most interesting when they produce new knowledge. This would be a mistake; thought experiments that seek understanding are just as powerful and interesting, and perhaps even more so. A growing number of epistemologists are emphasizing the importance of understanding for epistemology, arguing that it should supplant knowledge as the central notion. In this chapter, I bring the literature on understanding in epistemology to bear on explicating the different ways (...) that thought experiments increase three important kinds of understanding: explanatory, objectual and practical. (shrink)

In this book of essays, he argues that morality cannot be defined solely by rational and universal principles; instead, a major place must be found for changing and conflicting ideals, values peculiar to specific times and cultures.

When people speak, their words never fully encode what they mean, and the context is always compatible with a variety of interpretations. How can comprehension ever be achieved? Wilson and Sperber argue that comprehension is an inference process guided by precise expectations of relevance. What are the relations between the linguistically encoded meanings studied in semantics and the thoughts that humans are capable of entertaining and conveying? How should we analyse literal meaning, approximations, metaphors and ironies? Is the ability (...) to understand speakers' meanings rooted in a more general human ability to understand other minds? How do these abilities interact in evolution and in cognitive development? MEANING AND RELEVANCE sets out to answer these and other questions, enriching and updating relevance theory and exploring its implications for linguistics, philosophy, cognitive science and literary studies. (shrink)

What role does the imagination play in scientific progress? After examining several studies in cognitive science, I argue that one thing the imagination does is help to increase scientific understanding, which is itself indispensable for scientific progress. Then, I sketch a transcendental justification of the role of imagination in this process.

This article explores three ways in which physics may involve counterpossible reasoning. The first way arises when evaluating false theories: to say what the world would be like if the theory were true, we need to evaluate counterfactuals with physically impossible antecedents. The second way relates to the role of counterfactuals in characterizing causal structure: to say what causes what in physics, we need to make reference to physically impossible scenarios. The third way is novel: to model metaphysical dependence in (...) physics, we need to consider counterfactual consequences of metaphysical impossibilities. Physics accordingly bears substantial and surprising counterpossible commitments. (shrink)

On 26 August 1974, Michel Foucault completed work on Discipline and Punish, and on that very same day began writing the first volume of The History of Sexuality. A little under ten years later, on 25 June 1984, shortly after the second and third volumes were published, he was dead. This decade is one of the most fascinating of his career. It begins with the initiation of the sexuality project, and ends with its enforced and premature closure. Yet in 1974 (...) he had something very different in mind for The History of Sexuality than the way things were left in 1984. Foucault originally planned a thematically organised series of six volumes, but wrote little of what he promised and published none of them. Instead over the course of the next decade he took his work in very different directions, studying, lecturing and writing about historical periods stretching back to antiquity. This book offers a detailed intellectual history of both the abandoned thematic project and the more properly historical version left incomplete at his death. It draws on all Foucault’s writings in this period, his courses at the Collège de France and lectures elsewhere, as well as material archived in France and California to provide a comprehensive overview and synthetic account of Foucault’s last decade. (shrink)

This paper explores the relationship between eugenics, disability, and dehumanization, with a focus on forms of eugenics beyond Nazi eugenics.

1. Animal Cruelty Industrial farming is appallingly abusive to animals. Pigs. In America, nine-tenths of pregnant sows live in “gestation crates. ” These pens are so small that the animals can barely move. When the sows are first crated, they may flail around, in an attempt to get out. But soon they give up. Crated pigs often show signs of depression: they engage meaningless, repetitive behavior, like chewing the air or biting the bars of the stall. The sows live like (...) this for four months. Gestation crates will be phased out in Europe by the end of 2012, but they will still be used in America.1 In nature, pigs nurse their young for about thirteen weeks. But in industrial farms, piglets are taken from their mothers after about ten days. Because the piglets are weaned prematurely, they develop a lifelong craving to suck and chew. But the farmers don’t want them sucking and chewing on other pigs’ tails. So the growers routinely snip off the tails of all their pigs. They do this with a pair of pliers and no anesthetic. However, the whole tail is not removed; a tender stump remains. The point is to render the area sensitive, so the pigs being chewed on will fight back. Which they do.2 Over 113 million pigs are slaughtered each year in America.3 Typically, these pigs are castrated, their needle teeth are clipped, and one of their ears is notched for identification —all without pain relief.4 In nature, pigs spend up to three quarters of their waking hours foraging and exploring their environment.5 But in the factory farms, “tens of thousands of hogs spend their entire lives ignorant of earth or straw or sunshine, crowded together beneath a metal roof standing on metal slats suspended over a septic tank. ”6 Bored, and in constant pain, the pigs must perpetually inhale the fumes of their own waste. These pigs often get sick, and their ill health is exacerbated by the overcrowding. In 2000, the U.S. Department of Agriculture compared hog farms containing over 10,000 pigs—which is the norm—with farms containing under 2,000 pigs. (shrink)

The Making of British Bioethics provides the first in-depth study of how philosophers, lawyers and other 'outsiders' came to play a major role in discussing and helping to regulate issues that used to be left to doctors and scientists. It details how British bioethics emerged thanks to a dynamic interplay between sociopolitical concerns and the aims of specific professional groups and individuals who helped create the demand for outside involvement and transformed themselves into influential 'ethics experts'. Highlighting this interplay helps (...) us appreciate how issues such as embryo research and assisted dying became high-profile 'bioethical' concerns in the late twentieth century, and why different groups now play a critical role in developing regulatory standards and leading public debates. The book draws on a wide range of original sources and will be of interest to historians of medicine and science, general historians and bioethicists. (shrink)

John D. Norton is responsible for a number of influential views in contemporary philosophy of science. This paper will discuss two of them. The material theory of induction claims that inductive arguments are ultimately justified by their material features, not their formal features. Thus, while a deductive argument can be valid irrespective of the content of the propositions that make up the argument, an inductive argument about, say, apples, will be justified (or not) depending on facts about apples. The argument (...) view of thought experiments claims that thought experiments are arguments, and that they function epistemically however arguments do. These two views have generated a great deal of discussion, although there hasn’t been much written about their combination. I argue that despite some interesting harmonies, there is a serious tension between them. I consider several options for easing this tension, before suggesting a set of changes to the argument view that I take to be consistent with Norton’s fundamental philosophical commitments, and which retain what seems intuitively correct about the argument view. These changes require that we move away from a unitary epistemology of thought experiments and towards a more pluralist position. (shrink)

I claim that one way thought experiments contribute to scientific progress is by increasing scientific understanding. Understanding does not have a currently accepted characterization in the philosophical literature, but I argue that we already have ways to test for it. For instance, current pedagogical practice often requires that students demonstrate being in either or both of the following two states: 1) Having grasped the meaning of some relevant theory, concept, law or model, 2) Being able to apply that theory, concept, (...) law or model fruitfully to new instances. Three thought experiments are presented which have been important historically in helping us pass these tests, and two others that cause us to fail. Then I use this operationalization of understanding to clarify the relationships between scientific thought experiments, the understanding they produce, and the progress they enable. I conclude that while no specific instance of understanding (thus conceived) is necessary for scientific progress, understanding in general is. (shrink)

Let us begin with the simple observation that applied mathematics can be very tough! It is a common occurrence that basic physical principle instructs us to construct some syntactically simple set of differential equations, but it then proves almost impossible to extract salient information from them. As Charles Peirce once remarked, you can’t get a set of such equations to divulge their secrets by simply tilting at them like Don Quixote. As a consequence, applied mathematicians are often forced to pursue (...) roundabout and shakily rationalized expedients if any useful progress is to be made. Often these provisional and quasi-empirical procedures within applied mathematics loom large in motivating the “anti-realist” or “anti-unificationist” conclusions of Nancy Cartwright and allied authors. (shrink)

How should physical entities be characterized? Physicalists, who have most to do with the notion, usually characterize the physical by reference to two components: 1. The physical entities are the entities treated by fundamental physics with the proviso that 2. Physical entities are not fundamentally mental (that is, do not individually possess or bestow mentality) Here I explore the extent to which the appeals to fundamental physics and to the NFM (“no fundamental mentality”) constraint are appropriate for characterizing the physical, (...) especially for purposes of formulating physicalism. Ultimately, I motivate and defend a version of an account incorporating both components: The physics-based NFM account: An entity existing at a world w is physical iff (i) it is treated, approximately accurately, by current or future (in the limit of inquiry, ideal) versions of fundamental physics at w, and (ii) it is not fundamentally mental (that is, does not individually either possess or bestow mentality). (shrink)

Essentialism is widely regarded as a mistaken view of biological kinds, such as species. After recounting why (sections 2-3), we provide a brief survey of the chief responses to the “death of essentialism” in the philosophy of biology (section 4). We then develop one of these responses, the claim that biological kinds are homeostatic property clusters (sections 5-6) illustrating this view with several novel examples (section 7). Although this view was first expressed 20 years ago, and has received recent discussion (...) and critique, it remains underdeveloped and is often misrepresented by its critics (section 8). (shrink)

National Book Award Finalist. How did humanity originate and why does a species like ours exist on this planet? Do we have a special place, even a destiny in the universe? Where are we going, and perhaps, the most difficult question of all, "Why?" In The Meaning of Human Existence, his most philosophical work to date, Pulitzer Prize–winning biologist Edward O. Wilson grapples with these and other existential questions, examining what makes human beings supremely different from all other species. (...) Searching for meaning in what Nietzsche once called "the rainbow colors" around the outer edges of knowledge and imagination, Wilson takes his readers on a journey, in the process bridging science and philosophy to create a twenty-first-century treatise on human existence—from our earliest inception to a provocative look at what the future of mankind portends. Continuing his groundbreaking examination of our "Anthropocene Epoch," which he began with The Social Conquest of Earth, described by the New York Times as "a sweeping account of the human rise to domination of the biosphere," here Wilson posits that we, as a species, now know enough about the universe and ourselves that we can begin to approach questions about our place in the cosmos and the meaning of intelligent life in a systematic, indeed, in a testable way. Once criticized for a purely mechanistic view of human life and an overreliance on genetic predetermination, Wilson presents in The Meaning of Human Existence his most expansive and advanced theories on the sovereignty of human life, recognizing that, even though the human and the spider evolved similarly, the poet's sonnet is wholly different from the spider's web. Whether attempting to explicate "The Riddle of the Human Species," "Free Will," or "Religion"; warning of "The Collapse of Biodiversity"; or even creating a plausible "Portrait of E.T.," Wilson does indeed believe that humanity holds a special position in the known universe. The human epoch that began in biological evolution and passed into pre-, then recorded, history is now more than ever before in our hands. Yet alarmed that we are about to abandon natural selection by redesigning biology and human nature as we wish them, Wilson soberly concludes that advances in science and technology bring us our greatest moral dilemma since God stayed the hand of Abraham. (shrink)

This paper offers an overview of "the species problem", arguing for a view of species as homeostatic property cluster kinds, positioning the resulting form of realism about species as an alternative to the claim that species are individuals and pluralistic views of species. It draws on taxonomic practice in the neurosciences, especially of neural crest cells and retinal ganglion cells, to motivate both the rejection of the species-as-individuals thesis and species pluralism.

The last three decades have witnessed a heated debate of the merits of intelligent design (ID) as a way to understand a number of observable natural phenomena. The present dispute has its roots in a much older discussion: that of natural theology, which has always had as its goal the discernment of design(s) attributable to God in the natural world. Despite its ongoing relevance, natural theology does not have a coherent scholarly history. Turning Points in Natural Theology from Bacon to (...) Darwin deftly fills that gap, analysing the argument of design during the period from Francis Bacon (1561-1626) to Charles Darwin (1809-82), with a specific focus on those moments at which the rhetorical terms changed significantly. (shrink)

Transformation of the sparrow and the butterfly -- Meeting the gods of poverty in a dream -- The greatest joys of the cicada and its cast-off shell -- The owl's understanding -- The centipede questions the snake -- The toad's way of the gods -- The mysterious technique of the cat -- Afterword by William Scott Wilson.

This book, which inaugurates the Princeton Monographs in Philosophy series, starts from Plato's analogy in the Republic between conflict in the soul and conflict in the city. Plato's solution required reason to impose agreement and harmony on the warring passions, and this search for harmony and agreement constitutes the main tradition in political philosophy up to and including contemporary liberal theory. Hampshire undermines this tradition by developing a distinction between justice in procedures, which demands that both sides in a conflict (...) should be heard, and justice in matters of substance, which will always be disputed. Rationality in private thinking consists in adversary reasoning, and so it does in public affairs. Moral conflict is eternal, and institutionalized argument is its only universally acceptable restraint and the only alternative to tyranny. In the chapter "Against Monotheism," Hampshire argues that monotheistic beliefs are only with difficulty made compatible with pluralism in ethics. In "Conflict and Conflict Resolution," he argues that socialism, seen as the proposal of extended political solutions for natural human ills, is still a relevant, yet strongly contested, ideal. (shrink)

Every action, touch, utterance, and look, every listening, taste, smell, and feel is a living question; but it is no ordinary propositional one-by-one question, rather it is a plenisentient sensing and probing non-propositional enquiry about how our world is, in its present continuous sense, and in relation to how we anticipate its becoming. I will take this assumption as my first premise and, by using the notion of enkinaesthesia, I will explore the ways in which an agent’s affectively-saturated co-engagement with (...) its world establishes patterns of co-articulation of meaning within the anticipatory affective dynamics and the experiential entanglement necessary for expedient action and adaptation. In advancing this thesis I will reject the minimalist notions of embodiment by amplifying and extending the claims made by the most radical of the embodied mind theories. Crucially, I will offer a new wave of embodiment theory which has at its core the radical extension of sensorimotor affect into the life and being of other agents where their experience is for us both direct and immediate. This I will present as an immanent intercorporeality. (shrink)

The impressive variation amongst biological individuals generates many complexities in addressing the simple-sounding question what is a biological individual? A distinction between evolutionary and physiological individuals is useful in thinking about biological individuals, as is attention to the kinds of groups, such as superorganisms and species, that have sometimes been thought of as biological individuals. More fully understanding the conceptual space that biological individuals occupy also involves considering a range of other concepts, such as life, reproduction, and agency. There has (...) been a focus in some recent discussions by both philosophers and biologists on how evolutionary individuals are created and regulated, as well as continuing work on the evolution of individuality. (shrink)

Species : visions and values -- Fantasies : seeing without what was within -- Prestiges : illusions in magic and art -- Glamours : demons and virtual worlds -- Images : the reformation of the eyes -- Apparitions : the discernment of spirits -- Sights : King Saul and King Macbeth -- Seemings : philosophical scepticism -- Dreams : the epistemology of sleep -- Signs : vision and the new philosophy.

Everyone loves something or somebody, and most people are concerned with loving another person like themselves, all equal. This book is based on the belief that getting clear about the concept and meaning of love between equals is essential for success in our practical lives. For how can we love properly unless we have a fairly clear idea of what love is? The book is written in ordinary language and for the ordinary person, without jargon or philosophical technicalities. It aims (...) to show that love between equals involves a single basic disposition, though that disposition expresses itself in various ways. Thus, after an introduction explaining the need for analysis and clarification, the author then deals in order with love as desire or need; with intrinsic friendship and sharing the self; with basic difficulties concerning power, dependence, altruism and paranoia; with sex and erotic love; and finally with the value in human life of love between equals. The work as a whole gives clear, coherent and practical guidance for all who wish to grasp what such love is really like. (shrink)

Perception solves computationally demanding problems at lightning fast speed. It recovers sophisticated representations of the world from degraded inputs, often in a matter of milliseconds. Any theory of perception must be able to explain how this is possible; in other words, it must be able to explain perception's computational tractability. One of the few attempts to move toward such an explanation has been the information encapsulation hypothesis, which posits that perception can be fast because it keeps computational costs low by (...) forgoing access to information stored in cognition. I argue that we have no compelling reason to believe that encapsulation explains (or even contributes to an explanation of) perceptual tractability, and much reason to doubt it. This is because there exist much deeper computational challenges for perception than information access, and these threaten to make the costs of access irrelevant. If this is right, it undermines a core computational motivation for encapsulation and sends us back to the drawing board for explanations of perceptual tractability. (shrink)