In his account of probable reasoning, Poincaré used the concept, or at least the language, of conventions. In particular, he claimed that the prior probabilities essential for inverse probable reasoning are determined conventionally. This paper investigates, in the light of Poincaré's well known claim about the conventionality of metric geometry, what this could mean, and how it is related to other views about the determination of prior probabilities. Particular attention is paid to the similarities and differences between Poincaré's conventionalism as (...) it applies to probabilities and de Finetti's subjectivism. The aim of the paper is to suggest that in accounts of the development of ideas about probable reasoning, particularly those customarily described as Bayesian, Poincaré's discussion deserves more attention than it has so far received. (shrink)

Russell's philosophy is rightly described as a programme of reduction of mathematics to logic. Now the theory of geometry developed in 1903 does not fit this picture well, since it is deeply rooted in the purely synthetic projective approach, which conflicts with all the endeavours to reduce geometry to analytical geometry. The first goal of this paper is to present an overview of this conception. The second aim is more far-reaching. The fact that such a theory of geometry was sustained (...) by Russell compels us to question the meaning of logicism: how is it possible to reconcile Russell's global reductionist standpoint with his local defence of the specificities of geometry? * This paper was first presented at the conference ‘Qu'est ce que la géométrie aux époques modernes et contemporaines?’, organized by the Universität Köln and the Archives Poincaré. I would like to thank Philippe Nabonnand for having enlightened me about the issues relative to projective geometry. I would like also to thank Nicholas Griffin, Brice Halimi, Bernard Linsky, Marco Panza, Ivahn Smadja for their helpful discussions. Many thanks also to the two anonymous referees for their useful suggestions. CiteULike Connotea Del.icio.us What's this? (shrink)

This essay considers the nature of conceptual frameworks in science, and suggests a reconsideration of the role played by philosophy in radical conceptual change. On Kuhn's view of conceptual conflict, the scientist's appeal to philosophical principles is an obvious symptom of incommensurability; philosophical preferences are merely “subjective factors” that play a part in the “necessarily circular” arguments that scientists offer for their own conceptual commitments. Recent work by Friedman has persuasively challenged this view, revealing the roles that philosophical concerns have (...) played in preparing the way for conceptual change, creating an enlarged conceptual space in which alternatives to the prevailing framework become intelligible and can be rationally discussed. If we shift our focus from philosophical themes or preferences to the process of philosophical analysis, however, we can see philosophy in a different and much more significant historic role: not merely as an external source of general heuristic principles and new conceptual possibilities, but, at least in the most important revolutionary developments, as an objective tool of scientific inquiry. I suggest that this approach offers some insight into the philosophical significance of Newton's and Einstein's revolutionary work in physics, and of the interpretation of their work by (respectively) Kant and the logical positivists. It also offers insight into the connections between modern philosophy of science and some traditional philosophical concerns about the nature of a priori knowledge. (shrink)

In this work we present the function and we determine the nature of conventions and hypotheses for the scientific foundations according with the conventionalist doctrine that arose in France during the turning of the XIX century to the XX. The doctrine was composed by Henri Poincaré, Pierre Duhem and Édouard Le Roy. Moreover, we analyze the relation that conventions and hypotheses can establish with metaphysical thesis through criteria used by scientists in order to determine the preference for certain theories. Thereunto, (...) we promote an immanent interpretation of published works between 1891 and 1905. As result, we reveal that the authors, though being classified as belonging to the same doctrine, don't have only common grounds, but also divergences. Poincaré and Le Roy agree that geometrical conventions are chosen in accordance with convenience criteria. However, they disagree about the value convenience aggregate to scientific knowledge. In regards to natural phenomena, the three authors agree that reality can't be described univocally by the same set of conventions and hypotheses. Yet, Poincaré and Duhem both believe that there are experimental, rational and axiological criteria that justify scientist's satisfaction with certain theories and we indicate how those criteria are related with metaphysics. We conclude that conventionalists, even if warily and implicitly, searched to approach metaphysics in order to justify scientific activity. (shrink)