Con la obra La construcción de la realidad social1 el filósofo norteamericano John Rogers Searle ha puesto el análisis filosófico del lenguaje en lo más fundamental de los estudios sociológicos. Su propuesta está enfocada en las estructuras y funciones sociales que determinan la creación y el mantenimiento de los hechos institucionales. Este artículo se propone mostrar cómo el lenguaje es constitutivo de estos hechos, bajo la orientación de los siguientes interrogantes: ¿cómo un grupo de individuos constituye una sociedad que (...) supera la individualidad de sus miembros?, ¿cómo garantizan los individuos la estabilidad de la sociedad?, ¿cómo se explican las diversas formas de interacción social? y ¿por qué medios se hace efectiva esa interacción? El punto de partida será el reconocimiento de la sujeción social en la interacción social de la cotidianidad, seguido de una breve presentación de la teoría general de hechos institucionales para evaluar, finalmente, la función del lenguaje en la creación de estos hechos y los orígenes del poder institucional. (shrink)

Text extracted from opening pages of book: Heritage.

Introduction A Brief Conceptual Framework for Biology PART ONE: UNDERSTANDING NATURE 1. The Antecedents of Scientific Thought Animism, Totemism, and Shamanism The Paleolithic View Mesopotamia Egypt 2. Aristotle and the Greek View of Nature The Science of Animal Biology The Parts of Animals The Classification of Animals The Aristotelian System Basic Questions 3. Those Rational Greeks? Theophrastus and the Science of Botany The Roman Pliny Hippocrates, the Father of Medicine Erasistratus Galen of Pergamum The Greek Miracle 4. The Judeo-Christian Worldview (...) The Bishop of Hippo Scholastic Thought Islamic Science Books on Beasts Antecedents of a Revolution 5. The Revival of Science Andreas Vesalius and the Study of Structure William Harvey and the Study of Function Sir Francis Bacon’s Great Instauration Induction, Hypothesis, Deduction The Very Small--Animalcules Robert Hooke and the Discovery of Cells 6. Figur’d Stones and Plastick Virtue Marine Life on Mountain Tops? Figured Stones of Unknown Creatures Baron Cuvier Quarries of the Paris Basin Catastrophism and Uniformitarianism William Smith and the Geological Column Understanding Nature in 1850 PART TWO: THE GROWTH OF EVOLUTIONARY THOUGHT 7. The Paradigm of Evolution First Questions The Paradigm of Natural Theology First Answers 8. Testing Darwins Hypotheses Have Life Forms Changed over Time? Do Species Evolve into Different Species over Time? Has There Been Time Enough for Evolution? Is Natural Selection the Mechanism of Change? The Genetic Basis of Natural Selection Accounting for the Diversity of Life 9. In the Light of Evolution Comparative Anatomy Embryonic Development Classification Microstructure Molecular Processes 10. Life over Time The Origin of Life The Rise of Multicelled Organisms What Is a Phylum? Burgess Shale Metazoans Early Evolution of the Vertebrates The Age of Dinosaurs Birds, Mammals, and Flowering Plants The Rancho La Brea Tar Pits Human Evolution The Role of Extinction in Evolution PART THREE: CLASSICAL GENETICS 11. Pangenesis What Is the Question? Hippocrates and Aristotle The Darwinian Answer Assembling the Data Formulating the Hypothesis by Induction Galton’s Rabbits 12. The Cell Theory The Discovery of Cells: Robert Hooke Schwann and Cells in Animals Gametes as Cells Omnis cellula e cellula? The Technology of Cell Research 13. The Hypothesis of Chromosomal Continuity The Ephemeral Nucleus Schneider, Flemming, and Cell Division The Chromosomes and inheritance Gamete Formation Fertilization 14. Mendel and the Birth of Genetics Model for Monohybrid Crosses Model for Dihybrid Crosses Mendel’s Laws Initial Opposition to Mendelism 15. Genetics + Cytology: 1900-1910 Sutton’s Model The Cytological Basis of Mendel’s Laws Boveri and Abnormal Chromosome Sets Variations in Mendelian Ratios The Discovery of Sex Chromosomes 16. The Genetics of the Fruit Fly Morgan’s First Hypothesis Morgan’s Second Hypothesis The Fly Room Linkage and Crossing-Over The Cytological Proof of Crossing-Over Mapping the Chromosomes The Final Proof The Determinants of Sex The Conceptual Foundations of Classical Genetics 17. The Structure and Function of Genes One Gene, One Enzyme The Substance of Inheritance The Watson-Crick Model of DNA Genes and the Synthesis of Proteins The Genetic Code PART FOUR: THE ENIGMA OF DEVELOPMENT 18. First Principles The Peripatetic Stagirite The Death and Rebirth of Scientific Thought Harvey and Malpighi A Two-Millennial Summing Up Preformation versus Epigenesis 19. The Century of Discovery Von Baer’s Discovery of the Mammalian Ovum Darwin’s Contribution to Embryology Haeckel and Recapitulation 20. Descriptive Embryology Germ Layers The External Development of the Amphibian Embryo The Internal Development of the Amphibian Embryo 21. The Dawn of Analytical Embryology His, Roux, and Mosaic Development Driesch and Regulative Development Novelty in Development Cell Lineage Nucleus or Cytoplasm? Fin de Siècle 22. Interactions during Development Amphibian Organizers Secondary Organizers The Reacting Tissue The Chemical Nature of the Organizer Putting It All Together Conclusion Further Reading References Illustration Credits Index. (shrink)

Toda teoría del significado debe ofrecer, básicamente, una explicación del fenómeno mediante el cual atribuimos a ciertos hechos o acciones un significado. A menos que una teoría tal pretenda proponer un uso restrictivo del término significar, deberá considerar, en primera instancia, los usos más relevantes o representativos de “significar”, para adecuarse con ello a la dimensión pragmática del problema y ofrecer así una comprensión general del significado. La propuesta de H. P. Grice satisface, con grandes méritos, este requisito. Su artículo (...) Meaning,1 publicado en 1957, es un caso ejemplar del proceder analítico en las investigaciones filosóficas sobre el lenguaje. (shrink)

"Comparative table : The chief philosophical woeks in France, Germany, England and America from 1851 to 1921." : [341] - [347].

The problem of Time is one of the most fascinating and yet most difficult of those questions to which the human mind applies itself in philosophical thought. Dean Inge, in his Philosophy of Plotinus , has referred to this problem as ‘the hardest in metaphysics,’ and we know that “from the time of Parmenides and Zeno to that of Mr. Bradley and M. Bergson, there has been no other problem that has seemed so baffling as that of Time.”.

Regardless of the theory of vagueness we adhere to, we all agree that no facts, known or practically knowable, suffice to determine the location of precise boundaries for vague concepts. According to the epistemic theory of vagueness, this ignorance is entirely an epistemic matter—vague concepts have sharp boundaries but we can never know their exact locations. Opposed to epistemicism is a view—or family of views—I shall call indeterminism. The indeterminist agrees with the epistemicist that we lack knowledge of the locations (...) of sharp boundaries to vague concepts but holds that this ignorance has a somewhat more dramatic source—vague concepts have no sharp boundaries for us to have knowledge of. In recent years, the epistemic theory of vagueness has come to joint the various versions of indeterminism as a theory well-enough supported by argument to demand to be taken seriously. In this paper, I shall try to explain why I am unconvinced by the body of argument that has been marshalled in support of epistemicism; I shall try to explain why we should continue to endorse an indeterminist picture of vagueness. (shrink)

In this text, first published in 1941, British theologian John Oman discusses how the First World War disturbed 'both faith and morals'.

In _A Common Faith,_ eminent American philosopher John Dewey calls for the “emancipation of the true religious quality” from the heritage of dogmatism and supernaturalism that he believes characterizes historical religions. He describes how the depth of religious experience and the creative role of faith in the resources of experience to generate meaning and value can be cultivated without making cognitive claims that compete with or contend with scientific ones. In a new introduction, Dewey scholar Thomas M. Alexander (...) contextualizes the text for students and scholars by providing an overview of Dewey and his philosophy, key concepts in _A Common Faith,_ and reactions to the text. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:298 HISTORY OF PHILOSOPHY has been able to read. The result here is a presentation which is inspired and meaningful itself, astonishing its contemporaries and impressing its deseendants. Now, thirty years later, anthropology and psychology have passed beyond L~vy-Bruhl and Spranger. The moderate idealist interpretation of religion as it is found in Parts IV and V, "The World" and "Forms," must give way to descriptive phenomenology and existential analysis, (...) taking into consideration the internal dialectics of religion as well as the dialectics between the religious and the secular. The domain of meaning (Sinnesreich) appears, upon closer consideration, to be a function of the domain of existence. Contemporary religious consciousness and the confrontation of different such consciousnesses would require a "Part Six." The necessarily brief methodology, attached as Epilegomeua to the substance of the book, only contains the remnants of phenomenological epistemology. Besides at least making the main work of Van der Leeuw more known to the Englishspeaking world, this edition may also stimulate phenomenological discussion where Geisteswissenscha /t has a different connotation than it does in continental Europe. In this discussion, several points will have to be made. Is this book a pure phenomenology, with its evaluative character, its tendency to psychological instead of philosophical foundation, and its lack of philosophy of human consciousness? It should be mid that, unfortunately, hardly any phenomenologist of religion has been philosophically trained. So questions like those of the relation between phenomenology and history, the nature of phenomenological objectivity, the premisses and limits of phenomenological understanding, not to say theological implications of any phenomenology of religion, remain open. Van der Leeuw himself, as a scholar and a man, touched on them, but they still have to be worked out. JACQUESWAARDENBURG University of California, Los Angeles Systematic Theology, III. By Paul Tillich. (Chicago, University of Chicago Press, 1963. Pp. 434. $6.95.) The publication of Tillich's Systematic Theology, Volume III, brings to completion the enterprise begun with Volume I in 1951 and Volume II in 1957. As the author tells us, the project of constructing a systematic theology began as far back as the 1920's at the University of Marburg. Suspended when Tillich fled Hitler's Germany in 1933, it was continued during his twenty years at Union Seminary and his years as a university professor at Harvard. Thus in a significant sense, Volume III completes the work of a lifetime. Yet in another equally important sense it marks the permanent incompleteness of this work. For while this is systematic theology in the sense that it acknowledges and works in terms of rationality or coherence, it is clearly not a system in any final, closed, or absolute sense. Not only does Tillich expressly deny any such aspiration, but his openness to facts and to other men's viewpoints, his mixture of humility and candor in the presence of large and difficult problems all make clear the validity of this denial. It is perhaps worth noting in the present context that at no point in Volume III or indeed throughout the whole Systematic Theology does Tillich appeal to any criterion of judgment other than reasoning from facts. At no point is the reader asked to accept any judgment "on faith" or on any extra-rational authority. To be sure, faith is a basic category for Tillich and a crucial one for the Systematic Theology. Indeed many pages are devoted to its exposition and explication, but never is it understood or used as a basis for accepting propositions beyond or against the evidence. Indeed that whole view of faith is abhorrent to Tillich, and a major theme of his work has been to seek an understanding of faith more adequate alike religiously and intellectually. Among contemporary theologians Tillich is preeminent for the seriousness of his commitment to philosophy. In an autobiographical sketch written many years ago, he placed himself on the border between philosophy and theology. As we read the present volume, the conclusion is borne home that he has continued to live on that border territory, maintaining BOOK REVIEWS 299 an active and significant relation to both adjoining realms. In a day of mutual isolation and often hostility between theology and philosophy... (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Remembering Lewis E. HahnGeorge C. H. Sun, President, John Howie, Professor Emeritus, Thomas Alexander, Professor and Director of Graduate Studies, Kenneth W. Stikkers, Professor and Chair, Randall Auxier, Professor, Robert Hahn, Professor, Joseph Wu, Professor Emeritus, Elizabeth R. Eames, Professor Emeritus, Martin Lu, Professor of Philosophy, George Kimball Plochmann, Professor Emeritus, Matt Sronkoski, Philosophy Graduate and Academic Adviser, Dave Clarke, Professor Emeritus, Eugenie Gatens-Robinson, Professor Emerita, Hans (...) H. Rudnick, Professor Emeritus, Stephen Bickham, Professor EmeritusPresident, and Don Mikula (bio)The following testimonials were offered on the occasion of a memorial gathering for Dr. Lewis E. Hahn held on February 19, 2005, and were compiled for presentation here by Sharon (Hahn) Crowell.A Tribute to Dr. Lewis E. Hahn (1908-2004) from a Global PerspectiveGeorge C. H. Sun President, Thomé H. Fang Institute, Inc., Mobile, AlabamaAmong the philosophical community in both the East and the West, no word of introduction is needed for our beloved Master, who was the recipient of numerous distinctions and honors, with titles that included "Man of the Year in Philosophy" and "Award of Lifetime Achievement." The very name "Lewis E. Hahn" itself already stands now for genuineness, dedication, and fulfillment.A great work is a dialogue with eternity; a great person is such a work. In less than thirty years he succeeded in developing Carbondale from what had been a small college town in the Midwest into the Mecca of American philosophy. His most important achievements were the Dewey Center and the Pepper Archives that he helped install at SIUC These, among other such institutions, will remain a unique contribution, a glory of American philosophy, and a monument in the history of human thought.For posterity Lewis E. Hahn will remain an object of wonder and amazement. How is it possible for one human being to have accomplished so much, so well, and in so short a span of time—less than one century—in breadth, depth, and diversity? Some one hundred years ago, by bridging the gap between the New World and the Old, William James was hailed as the great genius of international friendship among philosophical thinkers, but we now find a greater genius in Lewis E. Hahn, who succeeded in bringing together the peoples of East and West from at least four continents: Europe, Australia, America (both North and Latin America), and Asia. To my knowledge, few of his predecessors and contemporaries have been half so widely read and liberal-minded as he was, in view of the range and scope of the Library of Living Philosophers that he helped continue after the passing of its founder, Dr. Paul A. Schilpp.What type of man was Hahn, our younger generation will wonder? Only a pluralist approach can help us understand the true character of such a legendary pluralist-contextualist. In short, he was "a full personality." As I recall, while working on my dissertation with him in the 1970s, we had a brief discussion on Confucius, the sage of ancient China. "A full personality!" was his laconic assessment. Suddenly I realized, to quote the Analects: "The Master is talking about himself!" For, as the Buddhists put it, only a Buddha can understand a Buddha. Or, as William James put it, only one who has philosophy can appreciate philosophy. Many friends [End Page 1] of my generation admire him so much; Te Chen of Hong Kong calls him "a great Confucian in America." Those who regret the loss of many precious Confucian virtues in China today have now rediscovered them in the person of Lewis E. Hahn! If Nietzsche called Kant "a great Chinese in Königsberg," it is simply because he had not encountered our own Master.A paradigm of academic leadership, Dr. Hahn is simply irreplaceable—this is a tribute I personally heard in Carbondale in the late 1960s. It is not an exaggeration to say that he was a superb administrator, and he could have been the best Secretary of the State we ever had, for he possessed more in the way of philosophical wisdom than all his predecessors put together! As a great teacher, he was no less "serene, good, learned, wise, and ardent" than... (shrink)

Biobased production has been promoted as a sustainable alternative to fossil resources. However, controversies over its impact on sustainability highlight societal concerns, value tensions and uncertainties that have not been taken into account during its development. In this work, the consideration of stakeholders’ values in a biorefinery design project is investigated. Value sensitive design is a promising approach to the design of technologies with consideration of stakeholders’ values, however, it is not directly applicable for complex systems like biorefineries. Therefore, some (...) elements of VSD, such as the identification of relevant values and their connection to a technology’s features, are brought into biorefinery design practice. Midstream modulation, an approach to promoting the consideration of societal aspects during research and development activities, is applied to promote reflection and value considerations during the design decision making. As result, it is shown that MM interventions during the design process led to new design alternatives in support of stakeholders' values, and allowed to recognize and respond to emerging value tensions within the scope of the project. In this way, the present work shows a novel approach for the technical investigation of VSD, especially for biorefineries. Also, based on this work it is argued that not only reflection, but also flexibility and openness are important for the application of VSD in the context of biorefinery design. (shrink)

Besides the pure pleasure of watching a dance performance, dance as a whole-body movement is becoming increasingly popular for health-related interventions. However, the science-based evidence for improvements in health or well-being through dance is still ambiguous and little is known about the underlying neurophysiological mechanisms. This may be partly related to the fact that previous studies mostly examined the neurophysiological effects of imagination and observation of dance rather than the physical execution itself. The objective of this pilot study was to (...) investigate acute effects of a physically executed dance with its different components (recalling the choreography and physical activity to music) on the electrical brain activity and its functional connectivity using electroencephalographic (EEG) analysis. Eleven dance-inexperienced female participants first learned a Modern Jazz Dance (MJD) choreography over three weeks (1 h sessions per week). Afterwards, the acute effects on the EEG brain activity were compared between four different test conditions: physically executing the MJD choreography with music, physically executing the choreography without music, imaging the choreography with music, and imaging the choreography without music. Every participant passed each test condition in a randomized order within a single day. EEG rest-measurements were conducted before and after each test condition. Considering time effects thephysically executed dance without musicrevealed in brain activity analysis most increases in alpha frequency and in functional connectivity analysis in all frequency bands. In comparison,physically executed dance with musicas well asimagined dance with musicled to fewer increases andimagined dance without musicprovoked noteworthy brain activity and connectivity decreases at all frequency bands. Differences between the test conditions were found in alpha and beta frequency betweenthe physically executed danceandthe imagined dance without musicas well as between thephysically executed dance withandwithout musicin the alpha frequency. The study highlights different effects of a physically executed dance compared to an imagined dance on many brain areas for all measured frequency bands. These findings provide first insights into the still widely unexplored field of neurological effects of dance and encourages further research in this direction. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Remembering Lewis E. HahnGeorge C. H. Sun, President, John Howie, Professor Emeritus, Thomas Alexander, Professor and Director of Graduate Studies, Kenneth W. Stikkers, Professor and Chair, Randall Auxier, Professor, Robert Hahn, Professor, Joseph Wu, Professor Emeritus, Elizabeth R. Eames, Professor Emeritus, Martin Lu, Professor of Philosophy, George Kimball Plochmann, Professor Emeritus, Matt Sronkoski, Philosophy Graduate and Academic Adviser, Dave Clarke, Professor Emeritus, Eugenie Gatens-Robinson, Professor Emerita, Hans (...) H. Rudnick, Professor Emeritus, Stephen Bickham, Professor EmeritusPresident, and Don Mikula (bio)The following testimonials were offered on the occasion of a memorial gathering for Dr. Lewis E. Hahn held on February 19, 2005, and were compiled for presentation here by Sharon (Hahn) Crowell.A Tribute to Dr. Lewis E. Hahn (1908-2004) from a Global PerspectiveGeorge C. H. Sun President, Thomé H. Fang Institute, Inc., Mobile, AlabamaAmong the philosophical community in both the East and the West, no word of introduction is needed for our beloved Master, who was the recipient of numerous distinctions and honors, with titles that included "Man of the Year in Philosophy" and "Award of Lifetime Achievement." The very name "Lewis E. Hahn" itself already stands now for genuineness, dedication, and fulfillment.A great work is a dialogue with eternity; a great person is such a work. In less than thirty years he succeeded in developing Carbondale from what had been a small college town in the Midwest into the Mecca of American philosophy. His most important achievements were the Dewey Center and the Pepper Archives that he helped install at SIUC These, among other such institutions, will remain a unique contribution, a glory of American philosophy, and a monument in the history of human thought.For posterity Lewis E. Hahn will remain an object of wonder and amazement. How is it possible for one human being to have accomplished so much, so well, and in so short a span of time—less than one century—in breadth, depth, and diversity? Some one hundred years ago, by bridging the gap between the New World and the Old, William James was hailed as the great genius of international friendship among philosophical thinkers, but we now find a greater genius in Lewis E. Hahn, who succeeded in bringing together the peoples of East and West from at least four continents: Europe, Australia, America (both North and Latin America), and Asia. To my knowledge, few of his predecessors and contemporaries have been half so widely read and liberal-minded as he was, in view of the range and scope of the Library of Living Philosophers that he helped continue after the passing of its founder, Dr. Paul A. Schilpp.What type of man was Hahn, our younger generation will wonder? Only a pluralist approach can help us understand the true character of such a legendary pluralist-contextualist. In short, he was "a full personality." As I recall, while working on my dissertation with him in the 1970s, we had a brief discussion on Confucius, the sage of ancient China. "A full personality!" was his laconic assessment. Suddenly I realized, to quote the Analects: "The Master is talking about himself!" For, as the Buddhists put it, only a Buddha can understand a Buddha. Or, as William James put it, only one who has philosophy can appreciate philosophy. Many friends [End Page 1] of my generation admire him so much; Te Chen of Hong Kong calls him "a great Confucian in America." Those who regret the loss of many precious Confucian virtues in China today have now rediscovered them in the person of Lewis E. Hahn! If Nietzsche called Kant "a great Chinese in Königsberg," it is simply because he had not encountered our own Master.A paradigm of academic leadership, Dr. Hahn is simply irreplaceable—this is a tribute I personally heard in Carbondale in the late 1960s. It is not an exaggeration to say that he was a superb administrator, and he could have been the best Secretary of the State we ever had, for he possessed more in the way of philosophical wisdom than all his predecessors put together! As a great teacher, he was no less "serene, good, learned, wise, and ardent" than... (shrink)

Christian PlantinCentre National de Recherche Scientifi que:CNRS. Universidad de Lyon.

Recent work in both the theory of the firm and of corporate law has called into question the appropriateness of analysing corporate law as ‘merely’ a set of standard form contracts. This article develops these ideas by focusing on property law's role in underpinning corporate enterprise. Rights to control assets are a significant mechanism of governance in the firm. However, their use in this way predicates some arrangement for stipulating which parties will have control under which circumstances. It is argued (...) that ‘property rules’—a category whose scope is determined functionally—protect the entitlements of parties to such sharing arrangements against each other's opportunistic attempts to grant conflicting entitlements to third parties. At the same time, the legal system uses a range of strategies to minimize the costs such protection imposes on third parties. The choice of strategy significantly affects co-owners’ freedom to customize their control-sharing arrangements. This theory is applied to give an account of the ‘proprietary foundations’ of corporate law, which has significant implications for the way in which the subject's functions are understood and evaluated. (shrink)

An infinite lottery machine is used as a foil for testing the reach of inductive inference, since inferences concerning it require novel extensions of probability. Its use is defensible if there is some sense in which the lottery is physically possible, even if exotic physics is needed. I argue that exotic physics is needed and describe several proposals that fail and at least one that succeeds well enough.

It is a popular perception that administrative receivers and their appointors hold «too much» power in relation to troubled companies. Many who hold this view have called for the reform of insolvency law in order to redress the balance of power. This issue is timely, because insolvency law is currently under review. This article argues that although the law's formal structure is imbalanced, it can nevertheless generate savings for parties, by allowing a concentrated creditor who has invested in information-gathering about (...) the debtor to conduct a private insolvency procedure. It is suggested that this procedure is likely to be more efficient than one conducted by a state official, and that it is likely to reduce the costs of debt finance, a matter of particular importance for small and medium-sized businesses. Empirical data are presented from 26 interviews with practitioners, which shed further light on the operation of receivership. Finally, the current law is compared with possible alternatives. It is argued that the case for wide-ranging reform is not made out. (shrink)

Although molecular biology has meant different things at different times, the term is often associated with a tendency to view cellular causation as conforming to simple linear schemas in which macro-scale effects are specified by micro-scale structures. The early achievements of molecular biologists were important for the formation of such an outlook, one to which the discovery of recombinant DNA techniques, and a number of other findings, gave new life even after the complexity of genotype–phenotype
relations had become apparent. Against this (...) background we outline how a range of scientific developments and conceptual considerations can be regarded as enabling and perhaps necessitating contemporary systems approaches. We suggest that philosophical ideas have a valuable part to play in making sense of complex scientific and disciplinary issues. (shrink)

Changes in healthcare financing increasingly rely upon patient cost-sharing to control escalating healthcare expenditures. These changes raise new challenges for physicians that are different from those that arose either under managed care or traditional indemnity insurance. Historically, there have been two distinct bases for arguing that physicians should not consider costs in their clinical decisions—an “aspirational ethic” that exhorts physicians to treat all patients the same regardless of their ability to pay, and an “agency ethic” that calls on physicians to (...) be trustworthy advisors to their patients. In the setting of greater patient cost-sharing, physicians' aspiration and agency roles increasingly conflict. Satisfactorily navigating the new terrain of consumer-driven healthcare requires physicians to consider these two roles and how they can best be reconciled so as to maximize quality of care while respecting the heterogeneity of patients' financial resources and willingness to pay. (shrink)

§ 1. Introduction. In this communication we present some recent results on the classification of Polish metric spaces up to isometry and on the isometry groups of Polish metric spaces. A Polish metric space is a complete separable metric space.Our first goal is to determine the exact complexity of the classification problem of general Polish metric spaces up to isometry. This work was motivated by a paper of Vershik [1998], where he remarks : “The classification of Polish spaces up to (...) isometry is an enormous task. More precisely, this classification is not ‘smooth’ in the modern terminology.” Our Theorem 2.1 below quantifies precisely the enormity of this task.After doing this, we turn to special classes of Polish metric spaces and investigate the classification problems associated with them. Note that these classification problems are in principle no more complicated than the general one above. However, the determination of their exact complexity is not necessarily easier.The investigation of the classification problems naturally leads to some interesting results on the groups of isometries of Polish metric spaces. We shall also present these results below.The rest of this section is devoted to an introduction of some basic ideas of a theory of complexity for classification problems, which will help to put our results in perspective. Detailed expositions of this general theory can be found, e.g., in Hjorth [2000], Kechris [1999], [2001]. (shrink)