Projet En développant son « empirisme constructif », Bas Van Fraassen est devenu une référence incontournable pour la philosophie des sciences contemporaine. Après la vague de critiques qui, vers les années 1960, avait fait perdre à l'empirisme logique sa prédominance dans le champ des idées, le réalisme scientifique semblait s'être imposé comme le seul compte rendu acceptable du travail et des orientations de la recherche. Quine avait beau énoncer ce que pourrait être un empirisme affranchi de ses deux « (...) dogmes » (l'intangibilité de la distinction vérités analytiques / vérités synthétiques, et la réduction des constructions aux « faits »), le programme d'une philosophie des sciences empiriste renouvelée restait à l'état d'esquisse. Mais par trois ouvrages successifs, Scientific Image (1980), Laws and symmetry (1989), et Quantum mechanics an empiricist view (1991), Van Fraassen a posé les bases d'un empirisme viable, parce que capable de prendre en charge la plupart des spécificités dont se prévaut le réalisme contre l'empirisme classique ou logique, et de rendre raison des développements les plus actuels de la physique. Contre l'empirisme classique ou logique, les réalistes font d'abord valoir que la réduction de toute réalité et de tout acte de référence aux phénomènes, ne rend justice ni à la pratique du langage courant ni à celle des sciences. Lorsque quelqu'un procède à une dénomination, il ne cherche pas à désigner par là une tranche d'apparaître, ou quelque ensemble fini et répertorié d'apparitions; il pointe vers "quelque chose" dont les modalités de manifestation sans fin assignable sont pour partie anticipées et pour partie ouvertes. De même, quand un chercheur scientifique parle de l'objet de ses investigations, il ne limite pas son discours à un ensemble fini de résultats d'expérience obtenus sous des conditions instrumentales actuellement disponibles; il renvoie à une entité dont la variété des manifestations futures est prévue aussi complètement que possible (et avec un succès croissant) par des cadres conceptuels et théoriques révisables. Face à cette objection, Van Fraassen fait jouer un rôle capital aux modèles dans sa version de l'empirisme.. (shrink)

Explanatory power is a complex theoretical virtue, not reducible to empirical strength or adequacy, which includes other virtues as its own preconditions. Since this virtue provides one of the main criteria by which theories are evaluated, it presents thus a challenge to any empiricist account of science. After a critical account of attempted explications of the concept of scientific explanation, this chapter offers a pragmatic account that identifies explanations with answers to why‐questions. Since such questions are set by the questioner, (...) and have their family of relevant direct answers determined by the presuppositions, values, and interests involved in the questioning, that makes explanation relative to contextual factors. On this understanding, evaluations of scientific explanation cannot play the role required for their use in support of scientific realism––and, incidentally, the large array of standard puzzles in the literature on this subject are solved. (shrink)

Scientific theories do much more than answer empirical questions. This can be understood along empiricist lines only if those other aspects are instrumental for the pursuit of empirical strength and adequacy, or serving other aims subordinate to these. This chapter accordingly addresses four main questions: Does the rejection of realism lead to a self‐defeating scepticism? Are scientific methodology and experimental design intelligible on any but a realist interpretation of science? Is the ideal of the unity of science, or even the (...) practice of using distinct theories in conjunction, intelligent on an empiricist view? What sense can an empiricist position accord to those theoretical virtues––such as simplicity, coherence, explanatory power––that are not reducible to empirical strength or adequacy? The answers to these questions rely strongly on the pragmatics of scientific inquiry, and advocate a ‘Clausewitz doctrine’ of experimentation as a continuation of theorizing by other means. (shrink)

This chapter parodies Aquinas’ Five Ways to prove the existence of God by displaying similar arguments reminiscent of those often given in support of scientific realism. This is followed by a parody of scientific realists’ attempts to defend themselves against objections to such arguments.

The opposition between empiricism and realism with respect to science is old: it appeared clearly in the seventeenth century sense of superiority of the ‘mechanical philosophy’ to Scholastic metaphysics, and continued for the next three centuries’ debates over the philosophical foundations of physics. Empiricist views developed by the logical positivists of Vienna and Berlin were defeated by the emergence of scientific realism in the mid‐twentieth century. This defeat was largely due to the inadequacy of the positivist theories of meaning and (...) language. To present a viable empiricist account of science, we need conceptions of theory structure, truth, and empirical adequacy that are essentially independent of a theory's linguistic formulation. Correlative to this discussion of the relationship between theory and world is the question what it is to accept a scientific theory––how much belief is involved? And what is involved other than belief? The position to be developed here will view scientific activity as one of construction rather than discovery: construction of models that must be adequate to the observable phenomena, and not discovery of the truth about postulated unobservable parts of nature. Acceptance of a scientific theory so viewed will have an irreducible pragmatic dimension in addition to involving only a modest amount of belief. (shrink)

The Aristotelian tradition in science, dominant before the advent of modern science, saw real modalities in nature: necessity, possibility, contingency, potentiality, and essence. Throughout the modern period and the early twentieth century, empiricists struggled to maintain that there was nothing to be found between matters of actual fact on the one hand and relations between ideas or words on the other. Probability has the logical form of a modality, but until the twentieth century, it could be construed as a measure (...) of ignorance, or of actual proportions and frequencies, not a basic parameter in nature itself. That changed with the advent of quantum mechanics and the admission of indeterminism as a theoretical possibility. The legitimacy of irreducible probabilities was admitted in the modelling of natural processes. The challenge to the empiricist now is to interpret probability as it appears there, and this includes the larger challenge of displaying an empiricistically acceptable role for modalities in general in the scientific image. This chapter provides a systematic critique of frequentist and propensity interpretations of physical probability, but also characterizes the models of probability theory as constructible from families of sequences constrained by limiting frequencies. This formal agreement with a certain kind of ’ideal frequency’ account is embedded in a philosophical view of modalities in general that turns on an account of the language of science on the level of pragmatics. (shrink)

What is the empirical content of a theory? If a theory is identified with one of its linguistic formulations, the only available answers allow for no non‐trivial distinction between empirical and non‐empirical content. The restriction of such a formulated theory to a narrow ‘observational’ vocabulary is not a description of the observable part of the world but a hobbled and hamstrung description of its entire domain, still with non‐empirical implications. Viewing a theory as identified through the family of its models––the (...) structures it makes available for modelling the phenomena––yields a new approach. The distinctions so made are illustrated with Newton's physics, absolute versus relative motion, nineteenth‐ century ether theory of electromagnetism, and quantum mechanics. A hermeneutic circle in the interpretation is noted, and the theory‐independence of the observable/unobservable distinction maintained. (shrink)

Metaphysicians speak of laws of nature in terms of necessity and universality; scientists, in terms of symmetry and invariance. In this book van Fraassen argues that no metaphysical account of laws can succeed. He analyzes and rejects the arguments that there are laws of nature, or that we must believe there are, and argues that we should disregard the idea of law as an adequate clue to science. After exploring what this means for general epistemology, the author develops the (...) empiricist view of science as a construction of models to represent the phenomena. (shrink)

Bas C. van Fraassen presents an original exploration of how we represent the world.

In this book van Fraassen develops an alternative to scientific realism by constructing and evaluating three mutually reinforcing theories.

What is empiricism and what could it be? Bas . van Fraassen, one of the world’s foremost contributors to philosophical logic and the philosophy of science, here undertakes a fresh consideration of these questions and offers a program for renewal of the empiricist tradition. The empiricist tradition is not and could not be defined by common doctrines, but embodies a certain stance in philosophy, van Fraassen says. This stance is displayed first of all in a searing, recurrent critique (...) of metaphysics, and secondly in a focus on experience that requires a voluntarist view of belief and opinion. Van Fraassen focuses on the philosophical problems of scientific and conceptual revolutions and on the not unrelated ruptures between religious and secular ways of seeing or conceiving of ourselves. He explores what it is to be or not be secular and points the way toward a new relationship between secularism and science within philosophy. (shrink)

What is empiricism and what could it be? Bas C. van Fraassen, one of the world's foremost contributors to philosophical logic and the philosophy of science, here undertakes a fresh consideration of these questions and offers a program for renewal of the empiricist tradition. The empiricist tradition is not and could not be defined by common doctrines but embodies a certain stance in philosophy, van Fraassen says. This stance is displayed first of all in a searing recurrent critique (...) of metaphysics, and second in a focus on experience that requires a voluntarist view of belief and opinion. (shrink)

What is empiricism and what could it be? Bas C. van Fraassen, one of the world’s foremost contributors to philosophical logic and the philosophy of science, here undertakes a fresh consideration of these questions and offers a program for renewal of the empiricist tradition. The empiricist tradition is not and could not be defined by common doctrines, but embodies a certain stance in philosophy, van Fraassen says. This stance is displayed first of all in a searing, recurrent critique (...) of metaphysics, and second in a focus on experience that requires a voluntarist view of belief and opinion._ _Van Fraassen focuses on the philosophical problems of scientific and conceptual revolutions and on the not unrelated ruptures between religious and secular ways of seeing or conceiving of ourselves. He explores what it is to be or not be secular and points the way toward a new relationship between secularism and science within philosophy. (shrink)

What does it mean to embed the phenomena in an abstract structure? Or to represent them by doing so? The semantic view of theories runs into a severe problem if these notions are construed either naively, in a metaphysical way, or too closely on the pattern of the earlier syntactic view. Constructive empiricism and structural realism will then share those difficulties. The problem will be posed as in Reichenbach's The Theory of Relativity and A Priori Knowledge, and realist reactions will (...) be examined, but they will be argued to dissolve upon scrutiny. (shrink)

A basic aim of E. Beth's work in philosophy of science was to explore the use of formal semantic methods in the analysis of physical theories. We hope to show that a general framework for Beth's semantic analysis is provided by the theory of semi-interpreted languages, introduced in a previous paper. After developing Beth's analysis of nonrelativistic physical theories in a more general form, we turn to the notion of the 'logic' of a physical theory. Here we prove a result (...) concerning the conditions under which semantic entailment in such a theory is finitary. We argue, finally, that Beth's approach provides a characterization of physical theory which is more faithful to current practice in foundational research in the sciences than the familiar picture of a partly interpreted axiomatic theory. (shrink)

This is surely a bit of Socrates' famous irony. He draws the analogy to explain how his friends should regard poetry as they regretfully banish it from the ideal state. But lovers were no more sensible then than they are now. The advice to banish poetry, undermined already by Plato's own delight and skill in drama, is perhaps undermined still further by this evocation of a 'sensible' lover who counts love so well lost. Yet Socrates' image is one of avowed (...) rationality and prudence. The sensible lover imitates the older literary example of Ulysses' tying himself to the mast. (The example belongs therefore to the class of problems treated in Elster (1979)). Both this lover and Ulysses foresee that under certain possible future conditions, their opinions, values and preferences will or would differ from what they are now, in a very definite fashion. To what extent is such foresight possible? Correspondingly (when we do not claim foreknowledge) to what extent is such opinion reasonable, rational, coherent, or consistent in some suitably broad sense? It is not easy to understand exactly what is possible or even logically permissible in this respect. In an earlier paper, "Belief and the Will", I argued for a principle ("Reflection") to govern such deliberation. Here I will both generalize the treatment of opinion in "Belief and the Will" and respond to criticism. Critical examples mainly resembled the story of Ulysses who foresaw a period of dysfunction (at the sound 2 of the sirens) in his epistemic and/or doxastic future. Other criticism focused on the model of opinion used (precise numerical subjective probability) and on the merits of Dutch Book arguments. The present argument will not rely on Dutch Book arguments and strategies, and the Reflection principle will be formulated so as to apply also to vague opinion. (shrink)

Constructive empiricism, the view introduced in The Scientific Image, is a view of science, an answer to the question "what is science?" Arthur Fine's and Paul Teller's contributions to this symposium challenge especially two key ideas required to formulate that view, namely the observable/unobservable and acceptance/belief distinctions. I wish to thank them not only for their insightful critique but also for the support they include. For they illuminate and counter some misunderstandings of Constructive Empiricism along the way. That leaves me (...) free to focus on those two main challenges. (shrink)

Structural realism as developed by John Worrall and others can claim philosophical roots as far back as the late 19th century, though the discussion at that time does not unambiguously favor the contemporary form, or even its realism. After a critical examination of some aspects of the historical background some severe critical challenges to both Worrall's and Ladyman's versions are highlighted, and an alternative empiricist structuralism proposed. Support for this empiricist version is provided in part by the different way in (...) which we can do justice to Worrall's original demands and in part by the viewpoint it provides (in contrast to e.g. Michael Friedman's) on the stability maintained through scientific theory change. Planck against the heretics 1.1 Poincaré on the meaning of Maxwell's equations 1.2 Two responses: reification and structuralism On the road to structuralism 2.1 The microscope 2.2 Mathematization of the world picture 2.3 The 18th–20th century The new structural realism 3.1 From scientific realism to structuralism 3.2 The Ladyman variant: objectivity and invariance 3.3 How is structural realism supported? An empiricist structuralism 4.1 Royal succession in science 4.2 Defence of the empiricist version 4.3 Structure: an empiricist view. (shrink)

Probabilism in epistemology does not have to be of the Bayesian variety. The probabilist represents a person''s opinion as a probability function; the Bayesian adds that rational change of opinion must take the form of conditionalizing on new evidence. I will argue that this is the correct procedure under certain special conditions. Those special conditions are important, and instantiated for example in scientific experimentation, but hardly universal. My argument will be related to the much maligned Reflection Principle (van Fraassen, (...) 1984, 1995), and partly inspired by the work of Brian Skyrms (1987). (shrink)

In recent papers Hans Halvorson has offered a critique of the semantic view of theories, showing that theories may be the same although the corresponding sets of models are different and, conversely, that theories may be different although the corresponding sets of models are the same. This critique will be assessed, first, as it pertains to issues concerning scientific models in the empirical sciences and, second, independent of any concern with empirical science.