Cette étude met en évidence la nécessité de situer les sciences naturelles sur le plan historique. L’attitude contemporaine à l’égard de la nature est très largement déterminée aujourd’hui par les sciences de la nature et par la technique modernes. Les changements des bases de la science moderne de la nature sont un symptôme de transformations profondes des fondements de notre existence «qui à leur tour provoquent certainement des réactions dans tous les autres domaines de la vie. De ce point de vue, il peut être important pour l’homme qui cherche à pénétrer l’essence de la nature, soit pour créer, soit pour expliquer, de se demander quelles transformations se sont produites dans l’image de la nature fournie par la science au cours des dernières décennies» (p. 10). La physique subit à l’heure actuelle un changement fondamental, dont la principale caractéristique est un retour à son auto-limitation première : c’est à travers une telle prise de conscience de ses limites qu’une science peut sauvegarder son contenu philosophique. – 1. La nature dans la physique contemporaine; – 2. Physique de l’atome et loi de la causalité; – 3. Les rapports entre la culture humaniste, les sciences de la nature et l’Occident; – 4. Sources historiques; – 5. Naissance de la conception mécanique et matérialiste. M.-M. V.

Principles of Scientific Sociology represents a major attempt to redirect the course of contemporary sociological thought. It is clear, well-organized, innovative, and original in its discussion of the context and methods of sociology conceived as a natural science. Wallace delineates the subject matter of sociology, classifies its variables, presents a logic of inquiry, and advocates the use of this logic for the acceptance or rejection of hypotheses or theories and for the solving of human problems. Social scientists, including political scientists, sociologists, anthropologists, historians, economists, social psychologists, and students of social phenomena among nonhumans, will find this work indispensable reading. Principles of Scientifc Sociology emphasizes the relationship between pure and applied sociological analysis. The essential contributions of each to the other are specified. Relationships between the substantive concepts of the sociology of humans, on the one hand, and the sociology of nonhumans, on the other, are systematized. In an attempt to put sociological analysis on a firm scientific basis, the book contains a concluding chapter focusing on central premises of natural science and their applicability to sociology. Wallace identifies the simple elements and relationships that sociological analysis requires if it is to lead to an understanding of complex social phenomena. On this basis, he considers the substantive elements and relations that comprise structural functionalism, historical materialism, symbolic interactionism, and other approaches to social data. He develops groundwork for standardizing these elements so that the contexts of different analyses may become rigorously comparable. The result is a fine, one-volume synthesis of sociological theory. M.-M. V.

This is a re-print of a book which scholars of philosophy, mathematics, and natural science consider as one of those "classics" every one in those fields must have read and mastered. It is also of interest to social scientists, like economists, because it delves into fundamental issues with the depth of philosophical thought and the rigor of a mathematician. The book was initially published by the Princeton University Press in 1949 (thus, 60 years ago); then it was, by and large, a translation and an expansion of a previous essay : the article "Philosophie der Mathematik und Naturwissenschaft" published in 1926 as a part of R. Oldenbourg's Handbuch der Philosophie (hence, nearly 80 years ago). As Nobel Prize Frank Wilczek recalls in the Introduction, Weyl was, with Einstein and von Neumann, part of the "trinity of refugee stars" that place Princeton's Institute for Advanced Studies at the forefront of research in many a field as they embodied the grand German literary and pan-European cultural tradition and rocketed into American pragmatism. – The book is divided into two parts, dealing respectively with Mathematics and Natural Science. Even though it includes several theorems and algorithms completely new and original at the time when they were formulated (and both the book and the previous essay published), it is not a technical text written only or mostly for specialists of the two main fields (mathematics and natural science). It is for a much broader readership with its roots in the European (not solely German) literature and thought. Throughout the book , we walk into the concepts of number and continuum, of the infinite, of geometry, of space, of time, of formation of theories, of the physical picture of the world. However, Hermann Weyl reminds us that he is not holding our hands in this voyage through mathematics and science. On the contrary, we and he have as guides Decartes, Leibnitz, Hume, Kant and all the other founding fathers of pan-European culture. Also, the voyage is not toward the discovery of new math and science technicalities : the final chapter deals with law, chance and especially freedom and the last appendix with how to reconcile basic questions on the origin of life and evolution and deep beliefs, like religious beliefs. M.-M. V.

In section 3.3 of Philosophy of Natural Science, Hempel argues that crucial tests are not sufficient enough to prove a given hypothesis or to disprove them. Hempel states what some may believe why a crucial test can prove or disprove a hypothesis. If there are two competing hypothesis which involve the same subject and no available evidence favors one or the other, then there exists a test, which will produce conflicting outcomes for the different hypotheses. This test is the so-called crucial test would then presumably refute one hypothesis while supporting the other. Hempel then presents his side of this argument using an example of past experiments involving the nature of light. He describes how Foucault performed an experiment involving the velocity of light through air and water. This experiment was meant to show whether light consists of waves or extremely small particles as presented by Newton. Foucault’s experiment was performed and the resulting outcome was used to refute Newton’s view of light as small particles traveling at a high velocity. Hempel believed that this test was not strong enough to completely support or refute either view of light. The experiment relied on the assumption that light as waves would travel faster in air than in water. However Hempel argues that the conception of light as streams of particles was too indefinite to assume that it would travel slower in air without additional assumptions about the motion of particles and their surrounding medium. So even though the results may seem to support and prove the wave hypothesis, it doesn’t necessarily disprove the particle theory. In fact Einstein later proposed a theory, which eliminated the classical wave theory, using support from an experiment by Lenard in 1903. But again as in the previous example one of the hypotheses was not definitely refuted, in this case being the wave theory. M.-M. V.

This paper attempts to motivate skepticism about the reality of mathematical objects. The aim of the paper is not to provide a general critique of mathematical realism, but to demonstrate the insufficiency of the arguments advanced by Michael Resnik. I argue that Resnik’s use of the concept of immanent truth is inconsistent with the treatment of mathematical objects as ontologically and epistemically continuous with the objects posited by the natural sciences. In addition, Resnik’s structuralist program, and his denial of relational properties, is incompatible with a realist metaphysics about mathematical objects.

In a talk given at Zürich in the late 1940s, Hermann Weyl discussed Ferdinand Gonseth’s dialectical epistemology and considered it as being restricted too strictly to aspects of historical change. His experiences with post-kantian dialectical philosophy, in particular Johann Gottlieb Fichte’s derivation of the concept of space and matter, had been a stronger dialectical background for his own 1918 studies in purely infinitesimal geometry and the early geometrically unified field theory of matter (extending the Mie-Hilbert program). Although now Weyl distantiated himself from the speculative features of his youthful philosophizing and in particular from his earlier enthusiasum for Fichte, he again had deep doubts as to the cultural foundations of modern mathematical sciences and its role in material culture of high modernity. For Weyl, philosophical «reflection» was a cultural necessity : he now turned towards Karl Jaspers’ and Martin Heidegger’s existentialism to find deeper grounds, similar to his turn towards Fichte’s philosophy after World War I. The discussion in the late 1940s can be read as a kind of post-World-War-II «Nachtrag» to Weyl’s more widely known philosophical comments on mathematics and the natural sciences published in the middle of the 1920s.