Cet article pose la question de savoir si les quarks — constituants élémentaires de la matière et dernières particules de la physique des hautes énergies à avoir été confirmées — peuvent être observés de manière directe ou indirecte. D’abord, des définitions antérieures de « l’observation » en physique seront examinées — en l’occurrence, celles proposées par Grover Maxwell, Bas van Fraassen et Dudley Shapere. Puis, leurs résultats seront comparés à une définition du concept d’observation et à une différenciation entre l’observation (...) directe et indirecte. Une possibilité de mettre en évidence les quarks de manière expérimentale est le phénomène des jet-events, qui représentent un type spécifique de désagrégation dans les détecteurs de particules. Ces jet-events contribuent à l’étude de cas ici centrale, puisqu’ils sont la preuve la plus convaincante à ce jour des quarks. L’examen de jet-events et leurs évaluations par des physiciens mènent à la conclusion que les quarks ne peuvent être observés, ni directement ni indirectement. Cette thèse sera comparée aux points de vue de Kristin Shrader-Frechette et Michela Massimi sur l’observabilité des quarks. On en tire la conclusion que les quarks ne sont pas observables, si l’on entend employer le terme « observation » dans un sens non métaphorique et en conservant une relation avec ses usages dans la vie quotidienne. (shrink)

Focusing on Shannon information, this article shows that, even on the basis of the same formalism, there may be different interpretations of the concept of information, and that disagreements may be deep enough to lead to very different conclusions about the informational characterization of certain physical situations. On this basis, a pluralist view is argued for, according to which the concept of information is primarily a formal concept that can adopt different interpretations that are not mutually exclusive, but each useful (...) in a different specific context. (shrink)

Astroparticle physics is a recent sub-discipline of physics that emerged from early cosmic ray studies, astrophysics, and particle physics. Its theoretical foundations range from quantum field theory to general relativity, but the underlying “standard models” of cosmology and particle physics are far from being unified. The paper explores the pragmatic strategies employed in astroparticle physics in order to unify a disunified research field, the concept of observation involved in these strategies, and their relations to scientific realism.

Experiments (E), computer simulations (CS) and thought experiments (TE) are usually seen as playing different roles in science and as having different epistemologies. Accordingly, they are usually analyzed separately. We argue in this paper that these activities can contribute to answering the same questions by playing the same epistemic role when they are used to unfold the content of a well-described scenario. We emphasize that in such cases, these three activities can be described by means of the same conceptual framework—even (...) if each of them, because they involve different types of processes, fall under these concepts in different ways. We further illustrate our claims by presenting a threefold case study describing how a TE, a CS and an E were indeed used in the same role at different periods to answer the same questions about the possibility of a physical Maxwellian demon. We also point at fluid dynamics as another field where these activities seem to be playing the same unfolding role. We analyze the importance of unfolding as a general task of science and highlight how our description in terms of epistemic functions articulates in a noncommittal way with the epistemology of these three activities and accounts for their similarities and the existence of hybrid forms of activities. We finally emphasize that picturing these activities as functionally substitutable does not imply that they are epistemologically substitutable. (shrink)

ABSTRACTIan Hacking puts forward a distinction between two kinds of scientific realism. According to scientific realism about theories, scientific theories are accepted as approximately true; according to scientific realism about unobservable entities, the theoretical terms occurring in scientific theories refer to existing, real entities. This article seeks to show that Claude Bernard's philosophy of science is a realist one about scientific theories, but anti-realist about unobservable entities. The term “fictionalism” is used here to stand for this sort of anti-realism about (...) unobservable entities. (shrink)

One premise of the underdetermination argument is that entailment of evidence is the only epistemic constraint on theory-choice. I argue that methodological rules can be epistemically significant, both with respect to observables and unobservables. Using an example from the history of medicine—Koch’s 1882 discovery of tuberculosis bacteria—I argue that even anti-realists ought to accept that these rules can break the tie between theories that are allegedly underdetermined. I then distinguish two types of underdetermination and argue that anti-realists, in order to (...) maintain the underdetermination argument, need to do more than show that theories are empirically equivalent: they need to show that a certain kind of underdetermination obtains. (shrink)

I argue that post-Kuhnian approaches to rational scientific change fail to appreciate several distinct philosophical requirements and relativist challenges that have been assumed to be, and may in fact be essential to any adequate conception of scientific rationality. These separate requirements and relativist challenges are clearly distinguished and motivated. My argument then focuses on Shapere's view that there are typically good reasons for scientific change. I argue: that contrary to his central aim, his account of good reasons ultimately presupposes the (...) requirement of universal standards of scientific reasoning; that the good reasons established by his account underdetermine the rationality of scientific change and allow that other changes would have been equally or even more rational; that as a result, Shapere's approach fails to meet what I characterize as the challenges of moderate, sociological, and cognitive relativism. (shrink)

Debates about scientific realism are closely connected to almost everything else in the philosophy of science, for they concern the very nature of scientific knowledge. Scientific realism is a positive epistemic attitude toward the content of our best theories and models, recommending belief in both observable and unobservable aspects of the world described by the sciences. This epistemic attitude has important metaphysical and semantic dimensions, and these various commitments are contested by a number of rival epistemologies of science, known collectively (...) as forms of scientific antirealism. This article explains what scientific realism is, outlines its main variants, considers the most common arguments for and against the position, and contrasts it with its most important antirealist counterparts. (shrink)

(i) Scientific realism is primarily a metaphysical doctrine about the existence and nature of the unobservables of science. (ii) There are good explanationist arguments for realism, most famously that from the success of science, provided abduction is allowed. Abduction seems to be on an equal footing, at least, with other ampliative methods of inference. (iii) We have no reason to believe a doctrine of empirical equivalence that would sustain the underdetermination argument against realism. (iv) The key to defending realism from (...) the pessimistic meta-induction is that we have greatly improved our capacity to understand the unobservable world over recent centuries. (shrink)

Richard Cytowic has done considerable service to the scientific study of synesthesia, conducting important research and publishing two recent books on the subject. The study of synesthesia raises interesting questions about scientific method, both because of the negative reception it received initially--often being viewed as tainted by a reliance upon introspective reports--and because of the connections Cytowic has found between synesthetic perception and the limbic system, thereby possibly undermining some of the claims to objectivity in perception and scientific method. I (...) dispute some of the more extreme methodological conclusions Cytowic draws from his work and reinforce others by reference to different arguments current within the philosophy of science. (shrink)

En este trabajo se plantea, en primer lugar, la conveniencia de distinguir en el proceso de la contrastación empirica de hipótesis y teorías entre observación cientifíca y percepción y, en segundo lugar, se muestra como el munda procesado a través de la percepción se erige en base o soporte empírico del conocimiento científico. Una de las consecuencias del trabajo es que Ia tesis de “la carga teórica" de Ia observación ha sido mal planteada, al dar par sentado que esa carga (...) teórica afecta tambien al procesamiento perceptivo de los outputs proporeionados al científico por el instrumental de observación.This paper first suggests that, in analyses of the empirical testing of hypotheses and theories, scientific observation should be distinguished from perception; and goes on to say that the world, as processed by perception, is the basis or empirical foundation of scientific knowledge. This thesis that observation is “theory-laden” has been flawed by its being articulated as applying not only to scientific observation but also to the perceptional processing of the output provided to the scientists by observational instruments. (shrink)

Our typology is based on two ground adequacy factors, one logical and one epistemic. Logically, the step from premises to conclusion may be conclusive or only ceteris paribus. Epistemically, warrants may be backed a priori or a posteriori. Hence there are four types of arguments: conclusive a priori, defeasible a priori, defeasible a posteriori, and prima facie conclusive a posteriori. We shall give an example of each and compare our scheme with other typologies.

This chapter (in French) compares the ways to access to events in science and in art. In particular, the Déotte's concept of "appareil" is discussed. To be published in Jean-Louis Déotte and Sylvestra Mariniello (ed.), Appareil et Intermédialité, L'Harmattan, 2007.

The physics literature contains many claims that elementary particles have been observed: such observational claims are, of course, important for the development of existential knowledge. Regarding claimed observations of short-lived unstable particles in particular, the use of the word 'observation' is based on the convention in physics that the observation of a short-lived unstable particle can be claimed when its predicted decay products have been observed with a significance of 5 sigma. This paper, however, shows that this 5 sigma convention (...) is inconsistent with existing concepts of observation by showing that unstable particles with a lifetime of less than 0.01 attosecond are fundamentally unobservable both from the perspective of Fox's recent concepts of direct and indirect observation, and from the perspective of Van Fraassen's notion of observability. This cognitive inaccessibility of parts of the subatomic world has far-reaching implications for physics, not the least of which is that the aforementioned convention is untenable: claims that such short-lived unstable particles have been observed will thus have to be retracted. The main implications are two incompleteness theorems for physics, respectively stating (i) that experiments cannot prove completeness of a physical theory predicting short-lived unstable particles, and (ii) that experiments cannot prove correctness of such a theory|one can at most test its empirical adequacy. On a general note, the conclusion is that the importance of philosophical arguments for particle physics is herewith demonstrated: it is, thus, a widespread misconception that philosophical arguments can be completely avoided. (shrink)