This volume is about the many ways we perceive. In nineteen new essays, philosophers and cognitive scientists explore the nature of the individual senses, how and what they tell us about the world, and how they interrelate. They consider how the senses extract perceptual content from receptoral information and what kinds of objects we perceive and whether multiple senses ever perceive a single event. Questions pertaining to how many senses we have, what makes one sense distinct from another, and whether and why distinguishing senses may be useful feature prominently. Contributors examine the extent to which the senses act in concert, rather than as discrete modalities, and whether this influence is epistemically pernicious, neutral, or beneficial. Many of the essays engage with the idea that it is unduly restrictive to think of perception as a collation of contents provided by individual sense modalities. Rather, contributors contend that to understand perception properly we need to build into our accounts the idea that the senses work together. In doing so, they aim to develop better paradigms for understanding the senses and thereby to move toward a better understanding of perception.

What do we see? We are visually conscious of colors and shapes, but are we also visually conscious of complex properties such as being John Malkovich? In this book, Susanna Siegel develops a framework for understanding the contents of visual experience, and argues that these contents involve all sorts of complex properties. Siegel starts by analyzing the notion of the contents of experience, and by arguing that theorists of all stripes should accept that experiences have contents. She then introduces a method for discovering the contents of experience: the method of phenomenal contrast. This method relies only minimally on introspection, and allows rigorous support for claims about experience. She then applies the method to make the case that we are conscious of many kinds of properties, of all sorts of causal properties, and of many other complex properties. She goes on to use the method to help analyze difficult questions about our consciousness of objects and their role in the contents of experience, and to reconceptualize the distinction between perception and sensation. Siegel's results are important for many areas of philosophy, including the philosophy of mind, epistemology, and the philosophy of science. They are also important for the psychology and cognitive neuroscience of vision.

Eye movements are a vital part of our interaction with the world. They play a pivotal role in perception, cognition, and education. Research in this field is now proceeding at a considerable pace and casting new light on how the eyes move and what information we can derive during the frequent and brief periods of fixation. However, the origins of this work are less well known, even though much of our knowledge was derived from this research with far more primitive equipment. This book is unique in tracing the history of eye movement research. It shows how great strides were made in this area before modern recording devices were available, especially in the measurement of nystagmus. When photographic techniques were adapted to measure discontinuous eye movements, from about 1900, many of the issues that are now basic to modern research were then investigated. One of the earliest cognitive tasks examined was reading, and it remains in the vanguard of contemporary research. Modern researchers in this field will be astonished at the subtleties of these early experimental studies and the ingenuity of interpretations that were advanced one and even two centuries ago. Though physicians often carried out the original eye movement research, later on it was pursued by psychologists - it is within contemporary neuroscience that we find these two strands reunited. Anyone interested in the origins of psychology and neuroscience will find much to stimulate and surprise them in this valuable new work.

The topic of this book is mental representation, a theoretical concept that lies at the core of cognitive science. Together with the idea that thinking is analogous to computational processing, this concept is responsible for the "cognitive turn" in the sciences of the mind and brain since the 1950s. Conceiving of cognitive processes (such as perception, reasoning, and motor control) as consisting of the manipulation of contentful vehicles that represent the world has led to tremendous empirical advancements in our explanations of behaviour. Perhaps the most famous discovery that explains behavior by appealing to the notion of mental representations was the discovery of 'place' cells that underlie spatial navigation and positioning, which earned researchers John O'Keefe, May-Britt Moser, and Edvard I. Moser a joint Nobel Prize in 2014. And yet, despite the empirical importance of the concept, there is no agreed definition or theoretical understanding of mental representation. This book constitutes a state-of-the-art overview on the topic of mental representation, assembling some of the leading experts in the field and allowing them to engage in meaningful exchanges over some of the most contentious questions. The collection gathers both proponents and critics of the notion, making room for debates dealing with the theoretical and ontological status of representations, the possibility of formulating a general account of mental representation which would fit our best explanatory practices, and the possibility of delivering such an account in fully naturalistic terms. Some contributors explore the relation between mutually incompatible notions of mental representation, stemming from the different disciplines composing the cognitive sciences (such as neuroscience, psychology, and computer science). Others question the ontological status and explanatory usefulness of the notion. And finally, some try to sketch a general theory of mental representations that could face the challenges outlined in the more critical chapters of the volume.

What is given to us in conscious experience? The Given is an attempt to answer this question and in this way contribute to a general theory of mental content. The content of conscious experience is understood to be absolutely everything that is given to one, experientially, in the having of an experience. Michelle Montague focuses on the analysis of conscious perception, conscious emotion, and conscious thought, and deploys three fundamental notions in addition to the fundamental notion of content: the notions of intentionality, phenomenology, and consciousness. She argues that all experience essentially involves all four things, and that the key to an adequate general theory of what is given in experience-of 'the given'-lies in giving a correct specification of the nature of these four things and the relations between them. Montague argues that conscious perception, conscious thought, and conscious emotion each have a distinctive, irreducible kind of phenomenology-what she calls 'sensory phenomenology', 'cognitive phenomenology', and 'evaluative phenomenology' respectively-and that these kinds of phenomenology are essential in accounting for the intentionality of these mental phenomena.

Vision dominates philosophical thinking about perception, and theorizing about experience in cognitive science has traditionally focused on a visual model. In a radical departure from established practice, Casey O'Callaghan provides a systematic treatment of sound and sound experience, and shows how thinking about audition and appreciating the relationships between multiple sense modalities can enrich our understanding of perception and the mind.
Sounds proposes a novel theory of sounds and auditory perception. Against the widely accepted philosophical view that sounds are among the secondary or sensible qualities, O'Callaghan argues that, on any perceptually plausible account, sounds are events. But this does not imply that sounds are waves that propagate through a medium, such as air or water. Rather, sounds are events that take place in one's environment at or near the objects and happenings that bring them about. This account captures the way in which sounds essentially are creatures of time, and situates sounds in a world populated by items and events that have significance for us. Sounds are not ethereal, mysterious entities.
O'Callaghan's account of sounds and their perception discloses far greater variety among the kinds of things we perceive than traditional views acknowledge. But more importantly, investigating sounds and audition demonstrates that considering other sense modalities teaches what we could not otherwise learn from thinking exclusively about the visual. Sounds articulates a powerful account of echoes, reverberation, Doppler effects, and perceptual constancies that surpasses the explanatory richness of alternative theories, and also reveals a number ofsurprising cross-modal perceptual illusions. O'Callaghan argues that such illusions demonstrate that the perceptual modalities cannot be completely understood in isolation, and that the visuocentric model for theorizing about perception --according to which perceptual modalities are discrete modes of experience and autonomous domains of philosophical and scientific inquiry--ought to be abandoned.

Our experience of objects (and consequently our theorizing about them) is very rich. We perceive objects as possessing individuation conditions. They appear to have boundaries in space and time, for example, and they appear to move independently of a background of other objects or a landscape. In Ontology Without Boundaries Jody Azzouni undertakes an analysis of our concept of object, and shows what about that notion is truly due to the world and what about it is a projection onto the world of our senses and thinking. Location and individuation conditions are our product: there is no echo of them in the world. Features, the ways that objects seem to be, aren't projections. Azzouni shows how the resulting austere metaphysics tames a host of ancient philosophical problems about constitution ("Ship of Theseus," "Sorities"), as well as contemporary puzzles about reductionism. In addition, it's shown that the same sorts of individuation conditions for properties, which philosophers use to distinguish between various kinds of odd abstracta-universals, tropes, and so on, are also projections. Accompanying our notion of an object is a background logic that makes cogent ontological debate about anything from Platonic objects to Bigfoot. Contemporary views about this background logic ("quantifier variance") make ontological debate incoherent. Azzouni shows how a neutral interpretation of quantifiers and quantifier domains makes sense of both philosophical and pre-philosophical ontological debates. Azzouni also shows how the same apparatus makes sense of our speaking about a host of items-Mickey Mouse, unicorns, Martians-that nearly all of us deny exist. It's allowed by what Azzouni shows about the background logic of our ontological debates, as well as the semantics of the language of those debates that we can disagree over the existence of things, like unicorns, without that background logic and semantics forcing ontological commitments onto speakers that they don't have.

Time Distortions in Mind brings together current research on aspects of temporal processing in clinical populations, in the ultimate hope of elucidating the interdependence between perturbations in timing and disturbances in the mind and brain. Such research may inform not only typical psychological functioning, but may also elucidate the psychological consequences of any pathophysiological differences in temporal processing. This collection of current knowledge on temporal processing in clinical populations is an excellent reference for the student and scientist interested in the topic, but it also serves as the stepping-stone to share ideas and push forward the advancement in understanding how distorted timing can lead to a disturbed brain and mind or vice versa. Contributors to this volume: Ryan D. Ward, Billur Avlar, Peter D Balsam, Deana B. Davalos, Jamie Opper, Yvonne Delevoye-Turrell, Helene Wilquin, Mariama Dione, Anne Giersch, Laurence Lalanne, Mitsouko van Assche, Patrick E. Poncelet, Mark A. Elliott, Deborah L. Harrington, Stephen M. Rao, Catherine R.G. Jones, Marjan Jahanshahi, Bon-Mi Gu, Anita J. Jurkowski, Jessica I. Lake, Chara Malapani, Warren H. Meck, Rebecca M. C. Spencer, Dawn Wimpory, Brad Nicholas, Elzbieta Szelag, Aneta Szymaszek, Anna Oron, Melissa J. Allman, Christine M. Falter, Argiro Vatakis, Alexandra Elissavet Bakou

How can we best describe the processes by which we visually perceive our environment? Contemporary perceptual theory still lacks a coherent theoretical position that encompasses both the limitations on the information that can be retained from a single eye fixation and the abundant phenomenal and behavioral evidence for the perception of an extended and coherent world. As a result, many leading theorists and researchers in visual perception are turning with new or renewed interest to the work of Julian Hochberg.
For over 50 years, in his own experimental research, in his detailed consideration of examples drawn from a wide range of visual experiences and activities, and most of all in his brilliant and sophisticated theoretical analyses, Hochberg has persistently engaged with the myriad problems inherent in working out the kind of coherent theoretical position the field currently lacks. The complexity of his thought and the wide range of areas into which Hochberg has pursued the solution to this central problem have, however, limited both the accessibility of his work and the appreciation of his accomplishment.
In this volume we seek to bring the full range of Hochberg's work to the attention of a wider audience by offering a selection of his key works, many taken from out-of-print or relatively inaccessible sources. To facilitate the understanding of his accomplishment, and of what his work has to offer to contemporary researchers and theorists in visual perception, we include commentaries on salient aspects of his work by 20 noted researchers.
In the Mind's Eye will be of interest to researchers working on topics such as perceptual organization, visual attention, spaceperception, motion perception, visual cognition, the relationship between perception and action, picture perception, and film, who are striving to obtain a deeper understanding of their own fields, and who want to integrate this understanding into a broader, unified view of visual perceptual processing.

While the field of vision science has grown significantly in the past three decades, there have been few comprehensive books that showed readers how to adopt a computional approach to understanding visual perception, along with the underlying mechanisms in the brain. Understanding Vision explains the computational principles and models of biological visual processing, and in particular, of primate vision. The book is written in such a way that vision scientists, unfamiliar with mathematical details, should be able to conceptually follow the theoretical principles and their relationship with physiological, anatomical, and psychological observations, without going through the more mathematical pages. For those with a physical science background, especially those from machine vision, this book serves as an analytical introduction to biological vision. It can be used as a textbook or a reference book in a vision course, or a computational neuroscience course for graduate students or advanced undergraduate students. It is also suitable for self-learning by motivated readers. in addition, for those with a focused interest in just one of the topics in the book, it is feasible to read just the chapter on this topic without having read or fully comprehended the other chapters. In particular, Chapter 2 presents a brief overview of experimental observations on biological vision; Chapter 3 is on encoding of visual inputs, Chapter 5 is on visual attentional selection driven by sensory inputs, and Chapter 6 is on visual perception or decoding. Including many examples that clearly illustrate the application of computational principles to experimental observations, Understanding Vision is valuable for students and researchers in computational neuroscience, vision science, machine and computer vision, as well as physicists interested in visual processes.

Originally published in 1976, the bibliography presented here was intended to provide a useful research tool for scholars and students of perception. The primary concentration of the authors' efforts has been on the philosophical literature during the period of 1935-1974.

The importance of facial expressions has led to a steadily growing body of empirical findings and theoretical analyses. Every decade has seen work that extends or challenges previous thinking on facial expression. The Science of Facial Expression provides an updated review of the current psychology of facial expression . This book summarizes current conclusions and conceptual frameworks from leading figures who have shaped the field in their various subfields, and will therefore be of interest to practitioners, students, and researchers of emotion in cognitive psychology, neuroscience, biology, anthropology, linguistics, affective computing, and homeland security. Organized in eleven thematic sections, The Science of Facial Expression offers a broad perspective of the "geography" of the science of facial expression. It reviews the scientific history of emotion perception and the evolutionary origins and functions of facial expression. It includes an updated compilation on the great debate around Basic Emotion Theory versus Behavioral Ecology and Psychological constructionism. The developmental psychology and social psychology of facial expressions is explored in the role of facial expressions in child development, social interactions, and culture. The book also covers appraisal theory, concepts, neural and behavioral processes, and lesser-known facial behaviors such as yawing, vocal crying, and vomiting. In addition, the book reflects that research on the "expression of emotion" is moving towards a significance of context in the production and interpretation of facial expression The authors expose various fundamental questions and controversies yet to be resolved, but in doing so, open many sources of inspiration to pursue in the scientific study of facial expression.

This book covers all aspects of the visual system from sensory aspects to eye movements, attention, and visual memory. There are many books that cover the psychology and physiology of a single aspect of vision, such as color vision or eye movements. Other larger texts may offer encyclopedic coverage of the psychology of all aspects of vision. However, this is the only book on the market covering the psychology, anatomy, and physiology of all aspects of the visual system in 300 pages. Each chapter addresses a separate aspect of vision, describing the basic phenomena, where in the brain this aspect of vision occurs, the properties of the cells in those areas, and the deficits that result from a lesion or stroke in those areas. In addition to extensive illustrations, the book contains the author's selection of the literature, from the classic 19th century papers to the present. This text is designed for graduate students and advanced undergraduates in psychology, optometry, physiology, anatomy, and medicine who want to get a broad view rather than one confined to their particular discipline.

Making a Machine That Sees Like Us explains why and how our visual perceptions can provide us with an accurate representation of the external world. Along the way, it tells the story of a machine (a computational model) built by the authors that solves the computationally difficult problem of seeing the way humans do. This accomplishment required a radical paradigm shift - one that challenged preconceptions about visual perception and tested the limits of human behavior-modeling for practical application.
The text balances scientific sophistication and compelling storytelling, making it accessible to both technical and general readers. Online demonstrations and references to the authors' previously published papers detail how the machine was developed and what drove the ideas needed to make it work. The authors contextualize their new theory of shape perception by highlighting criticisms and opposing theories, offering readers a fascinating account not only of their revolutionary results, but of the scientific process that guided the way.

In the last few years there has been an explosion of philosophical interest in perception; after decades of neglect, it is now one of the most fertile areas for new work. Perceptual Experience presents new work by fifteen of the world's leading philosophers. All papers are written specially for this volume, and they cover a broad range of topics dealing with sensation and representation, consciousness and awareness, and the connections between perception and knowledge and between perception and action. This will be the book on the philosophy of perception, a fascinating resource for philosophers and psychologists.

In "Mind and Maze: Spatial Cognition and Environmental Behavior," Ann Sloan Devlin takes the reader on a journey from the crib to the city, examining at each life phase the development of how we know where we are in space and our appreciation of spatial relationships. The author explores gender differences in spatial cognition, the parts of the brain that handle spatial relationships, and the principles that mapmakers and others use to create navigational aids, all in an effort to better identify the connection between certain behaviors and their relevance to real-world tasks. This book offers students, researchers, architects, and policy makers a fuller appreciation of spatial cognition and its impact on society.

Devlin examines a fundamental aspect of human behavior, that we are animals for whom functioning in space is essential to our survival, in a uniquely interdisciplinary way. Rather than narrowly limit her focus to a specific area of psychology, she discusses spatial cognition from many perspectives, from urban planning and architecture to developmental psychology and neuroscience. This book offers students, researchers, architects, and policy makers a fuller appreciation of spatial cognition and its impact on society.

Historical analysis reveals that perceptual theories and models are doomed to relatively short lives. The most popular contemporary theories in perceptual science do not have as wide an acceptance among researchers as do some of those in other sciences. To understand these difficulties, the authors of the present volume explore the conceptual and philosophical foundations of perceptual science. Based on logical analyses of various problems, theories, and models, they offer a number of reasons for the current weakness of perceptual explanations. New theoretical approaches are also proposed. At the end of each chapter, dicussants contribute to the conclusions by critically examining the authors' ideas and analyses.

Our visual system can process information at both conscious and unconscious levels. Understanding the factors that control whether a stimulus reaches our awareness, and the fate of those stimuli that remain at an unconscious level, are the major challenges of brain science in the new millennium. Since its publication in 1984, Visual Masking has established itself as a classic text in the field of cognitive psychology. In the years since, there have been considerable advances in the cognitive neurosciences, and a growth of interest in the topic of consciousness, and the time is ripe for a new edition of this text. Where most current approaches to the study of visual consciousness adopt a 'steady-state' view, the approach presented in this book explores its dynamic properties. This new edition uses the technique of visual masking to explore temporal aspects of conscious and unconscious processes down to a resolution in the millisecond range. The 'time slices' through conscious and unconscious vision revealed by the visual masking technique can shed light on both normal and abnormal operations in the brain. The main focus of this book is on the microgenesis of visual form and pattern perception - microgenesis referring to the processes occurring in the visual system from the time of stimulus presentation on the retinae to the time, a few hundred milliseconds later, of its registration at conscious or unconscious perceptual and behavioural levels. The book takes a highly integrative approach by presenting microgenesis within a broad context encompassing visuo-temporal phenomena, attention, and consciousness.

The disciplines of cognitive neuroscience, development, and psychopathology are complementary in the study of human perception and attention, even though each discipline emerges from a decidedly different and sometimes incompatible worldview. The meeting of researchers across these disciplines results in a fruitful cross-fertilization that ultimately leads to better science within each discipline and a joint scientific endeavor that is greater than the sum of its parts.
Cognitive Neuroscience, Development, and Psychopathology: Typical and Atypical Developmental Trajectories of Attention unites scholars sharing common interests in the development of attention and related areas of functioning with different perspectives and methodologies. The volume does not impose a single framework for discussing the relevant issues, but rather the authors highlight the importance of their own approaches to the study of the typical and atypical development of attention. Drs. Burack, Enns, and Fox have organized the chapters into three sections: Atypical Environments, Threat, and the Development of Individual Differences in Attention; The Organization of the Development of Attention in Typical and Atypical Processing; and The Case of Orienting Attention in Developing an Integrated Science. Discussion topics include cognitive bias modification, attention and the development of anxiety disorders, deficient anchoring, reflexive and abnormal social orienting in autism, and social attention. This volume is a unique and critical resource for researchers in communication disorders, developmental and cognitive psychology, human development, neuroscience, and educational and counseling psychology.

Although current debates in epistemology and philosophy of mind show a renewed interest in perceptual illusions, there is no systematic work in the philosophy of perception and in the psychology of perception with respect to the concept of illusion and the relation between illusion and error. This book aims to fill that gap.

Every time you consult a calendar or clock, other people are thinking for you. Most users of these tools only know how to interpret the representations of time these objects provide, not the logics behind the representations. Those logics were others' ideas. This book looks at how the objects we use to think about time shape our thoughts. Such objects empower us to think about time certain ways, but they also contain hidden assumptions about time that deflect our awareness away from the complicated rhythms of our lives and our world. Because time ties together so many aspects of our lives, this book is able to explore the nexus of objects, cognition, culture, and even biology, and to do so in relationship to

This book follows a successful symposium organized in June 2009 at the Human Brain Mapping conference. The topic is at the crossroads of two domains of increasing importance and appeal in the neuroimaging/neuroscience community: multi-modal integration, and social neuroscience. Most of our social interactions involve combining information from both the face and voice of other persons: speech information, but also crucial nonverbal information on the person's identity and affective state. The cerebral bases of the multimodal integration of speech have been intensively investigated; by contrast only few studies have focused on nonverbal aspects of face-voice integration. This work highlights recent advances in investigations of the behavioral and cerebral bases of face-voice multimodal integration in the context of person perception, focusing on the integration of affective and identity information. Several research domains are brought together. Behavioral and neuroimaging work in normal adult humans included are presented alongside evidence from other domains to provide complementary perspectives: studies in human children for a developmental perspective, studies in non-human primates for an evolutionary perspective, and studies in human clinical populations for a clinical perspective. Several research domains are brought together. Behavioral and neuroimaging work in normal adult humans included are presented alongside evidence from other domains to provide complementary perspectives: studies in human children for a developmental perspective, studies in non-human primates for an evolutionary perspective, and studies in human clinical populations for a clinical perspective. Several research domains are brought together. Behavioral and neuroimaging work in normal adult humans included are presented alongside evidence from other domains to provide complementary perspectives: studies in human children for a developmental perspective, studies in non-human primates for an evolutionary perspective, and studies in human clinical populations for a clinical perspective. Several research domains are brought together. Behavioral and neuroimaging work in normal adult humans included are presented alongside evidence from other domains to provide complementary perspectives: studies in human children for a developmental perspective, studies in non-human primates for an evolutionary perspective, and studies in human clinical populations for a clinical perspective.

'By the deepest thinker about this topic since Darwin' Daniel Gilbert, author of the bestseller Stumbling on Happiness

'Fascinating . . . a thought-provoking journey into emotion science' The Wall Street Journal

'This meticulous, well-researched, and deeply thought out book provides information about our emotions - what they are, where they come from, why we have them. For anyone who has struggled to reconcile brain and heart, this book will be a treasure; it explains the science without short-changing the humanism of its topic' Andrew Solomon, bestselling author of Far From the Tree and The Noonday Demon

When you feel anxious, angry, happy, or surprised, what's really going on inside of you?

Many scientists believe that emotions come from a specific part of the brain, triggered by the world around us. The thrill of seeing an old friend, the fear of losing someone we love - each of these sensations seems to arise automatically and uncontrollably from within us, finding expression on our faces and in our behaviour, carrying us away with the experience.

This understanding of emotion has been around since Plato. But what if it is wrong? In How Emotions Are Made, pioneering psychologist and neuroscientist Lisa Feldman Barrett draws on the latest scientific evidence to reveal that our common-sense ideas about emotions are dramatically, even dangerously, out of date - and that we have been paying the price. Emotions aren't universally pre-programmed in our brains and bodies; rather they are psychological experiences that each of us constructs based on our unique personal history, physiology and environment.

This new view of emotions has serious implications: when judges issue lesser sentences for crimes of passion, when police officers fire at threatening suspects, or when doctors choose between one diagnosis and another, they're all, in some way, relying on the ancient assumption that emotions are hardwired into our brains and bodies. Revising that conception of emotion isn't just good science, Barrett shows; it's vital to our well-being and the health of society itself.

Psychological research using time as a variable has been extensive since the era of Wundt and Ebbinghaus. The care of and research on dementia patients highlights a unique need for understanding and applying the concepts of time and space. This volume, unique in its development of a model for time-space orientation, proposes that understanding the needs of these patients is increased by consideration of the DEGREESIdis DEGREESRorientation caused by dementia. Included is a review of the history of time and time measurement, a survey of psychological literature using time as a variable across the life span, and a model of time orientation applied to persons who have developed dementia.

Conditions leading to dementia are described, and a rationale proposed for the effects of time/space disorientation in behavioral disturbances. Suggestions for applications and future research are included. Scholars and researchers interested in time awareness and orientation, as well as professionals in psychology, sociology, and gerontology caring for dementia patients, will find the material here useful.

The distinguished contributors to this volume have been set the problem of describing how we know where to move our eyes. There is a great deal of current interest in the use of eye movement recordings to investigate various mental processes. The common theme is that variations in eye movements indicate variations in the processing of what is being perceived, whether in reading, driving or scene perception. However, a number of problems of interpretation are now emerging, and this edited volume sets out to address these problems. The book investigates controversies concerning the variations in eye movements associated with reading ability, concerning the extent to which text is used by the guidance mechanism while reading, concerning the relationship between eye movements and the control of other body movements, the relationship between what is inspected and what is perceived, and concerning the role of visual control attention in the acquisition of complex perceptual-motor skills, in addition to the nature of the guidance mechanism itself.
The origins of the volume are in discussions held at a meeting of the European Society for Cognitive Psychology (ESCOP) that was held in Wurzburg in September 1996. The discussions concerned the landing effect in reading, an effect, that if substantiated, would provide evidence of the use of parafoveal information in eye guidance, and these discussions were explored in more detail at a small meeting in Chamonix, in February 1997. Many of the contributors to this volume were present at the meeting, but the arguments were not resolved in Chamonix either. Other leaders in the field were invited to contribute to the discussion, and this volume is the product. The argument remains unresolved, but the problem is certainly clearer.