The author endeavours to show two things: first, that Schrödingers (and Eckarts) demonstration in March (September) 1926 of the equivalence of matrix mechanics, as created by Heisenberg, Born, Jordan and Dirac in 1925, and wave mechanics, as created by Schrödinger in 1926, is not foolproof; and second, that it could not have been foolproof, because at the time matrix mechanics and wave mechanics were neither mathematically nor empirically equivalent. That they were is the Equivalence Myth. In order to make the (...) theories equivalent and to prove this, one has to leave the historical scene of 1926 and wait until 1932, when von Neumann finished his magisterial edifice. During the period 1926–1932 the original families of mathematical structures of matrix mechanics and of wave mechanics were stretched, parts were chopped off and novel structures were added. To Procrustean places we go, where we can demonstrate the mathematical, empirical and ontological equivalence of ‘the final versions of’ matrix mechanics and wave mechanics. -/- The present paper claims to be a comprehensive analysis of one of the pivotal papers in the history of quantum mechanics: Schrödingers equivalence paper. Since the analysis is performed from the perspective of Suppes structural view (‘semantic view’) of physical theories, the present paper can be regarded not only as a morsel of the internal history of quantum mechanics, but also as a morsel of applied philosophy of science. The paper is self-contained and presupposes only basic knowledge of quantum mechanics. For reasons of length, the paper is published in two parts; Part I appeared in the previous issue of this journal. Section 1 contains, besides an introduction, also the papers five claims and a preview of the arguments supporting these claims; so Part I, Section 1 may serve as a summary of the paper for those readers who are not interested in the detailed arguments. (shrink)

There is nowadays consensus in the community of didactics of science regarding the need to include the philosophy of science in didactical research, science teacher education, curriculum design, and the practice of science education in all educational levels. Some authors have identified an ever-increasing use of the concept of ‘theoretical model’, stemming from the so-called semantic view of scientific theories. However, it can be recognised that, in didactics of science, there are over-simplified transpositions of the idea of model. In this (...) sense, contemporary philosophy of science is often blurred or distorted in the science education literature. In this paper, we address the discussion around some meta-theoretical concepts that are introduced into didactics of science due to their perceived educational value. We argue for the existence of a ‘semantic family’, and we characterise four different versions of semantic views existing within the family. In particular, we seek to contribute to establishing a model-based didactics of science mainly supported in this semantic family. (shrink)

This dissertation examines the dynamical dark matter problem in twentieth century astrophysics from the point of view of History and Philosophy of Science. The dynamical dark matter problem describes the situation astronomers find themselves in with regard to the dynamics of large scale astrophysical systems such as galaxies and galaxy clusters: The observed motions are incompatible with the visible distribution matter given the accepted law of gravitation. This discrepancy has two classes of possible solutions: either there exists copious amounts of (...) some kind of matter that neither emits nor absorbs radiation , or the law of gravitation must be revised. ;Chapter 2 describes the physical and philosophical foundations of dynamical inferences---inferences from discrepancies between well-founded theoretical expectations and reliable observations to the characteristics of candidate solutions. Chapter 3 discusses the history of dark matter . Chapter 4 reviews the present evidence bearing on the dark matter problem. Chapter 5 evaluates the important candidate matter solutions in light of the available evidence. Chapter 6 evaluates two candidate gravitational solutions on evidential and methodological grounds, and addresses the problem of theory choice. I do not try to solve the dark matter problem, but to uncover and evaluate patterns of inference involved in evidential arguments for and against candidate solutions. ;I show that Newton's "Reasoning from Phenomena" is a good framework from which to understand what is going on in this field. I argue that "higher order" and especially non-dynamical evidence is the best hope for solving this problem in dynamics. This is so in part because of "the dark matter double bind": the very existence of the dark matter problem means that we cannot be sure of the overall matter distribution in astrophysical systems, and this in turn means that the observed motions by themselves cannot provide relative confirmation of any theory of gravitational interactions taking place at these scales. I use Newton's Rules of Reasoning to argue that we should retain General Relativity as our theory of gravity at galactic and greater scales, despite the lack of positive evidence to confirm it over its rivals at these scales. (shrink)

The relativistic revolution led to varieties of neo-Kantianism in which constitutive principles define the object of scientific knowledge in a domain-dependent and historically mutable manner. These principles are a priori insofar as they are necessary premises for the formulation of empirical laws in a given domain, but they lack the self-evidence of Kant’s a priori and they cannot be identified without prior knowledge of the theory they purport to frame. In contrast, the rationalist endeavors of a few masters of theoretical (...) physics have led to comprehensibility conditions that are easily admitted in a given domain and yet suffice to generate the theory of this domain. The purpose of this essay is to compare these two kinds of relativized a priori, to discuss the nature of the comprehensibility conditions, and to demonstrate their effectiveness in a modular conception of physical theories. (shrink)

I examine two claims that arise in Brown’s account of inertial motion. Brown claims there is something objectionable about the way in which the motions of free particles in Newtonian theory and special relativity are coordinated. Brown also claims that since a geodesic principle can be derived in Einsteinian gravitation, the objectionable feature is explained away. I argue that there is nothing objectionable about inertia and that while the theorems that motivate Brown’s second claim can be said to figure in (...) a deductive-nomological explanation, their main contribution lies in their explication rather than their explanation of inertial motion. (shrink)

Esta carta abierta es el resultado del intenso intercambio epistolar que he mantenido con el Prof. Torretti durante muchos años, y a través del cual me he enriquecido ampliamente en el pensar filosófico. Aquí señalo nuestros acuerdos en la adopción de una perspectiva de inspiración kantiana, y en el reconocimiento del papel que juega la dimensión pragmática en la ciencia. No obstante, nos distanciamos en cuanto al peso que le adjudicamos al realismo en nuestras posturas. Estas discusiones con el Prof. (...) Torretti me permitieron explicitar mi modo de vivir la filosofía como praxis filosófica, dirigida a enfrentarme con ciertos aspectos del modo en que actualmente se hace ciencia. (shrink)

Any advanced theory of physics contains modules defined as essential components that are themselves theories with different domains of application. Different kinds of modules can be distinguished according to the way in which they fit in the symbolic and interpretive apparatus of a theory. The number and kind of the modules of a given theory vary as the theory evolves in time. The relative stability of modules and the variability of their insertion in other theories play a vital role in (...) the application, comparison, construction, and communication of theories. Modularity conveys some global unity to physics through the sharing of modules by diverse theories. This alternative to rigid hierarchies and holistic totalities permits a dynamical, plastic, and symbiotic approach to physical theory. (shrink)

Three major views of the observation?theory relation are now extant: (1) Observation and theory are mutually independent and observation provides the basis for evaluating theories. (2) Observations are theory?dependent and do not provide objective grounds for evaluating theories. (3) The concept of observation should be extended in a way that includes many so?called ?theoretical?entities? among the observables. Analyses of these views set the stage for a new approach that incorporates lessons learned from discussions of earlier accounts. The central idea of (...) this new approach is that empirical testing requires comparison of results arrived at by derivation from the theory being tested (plus appropriate auxiliary premises) with results derived from an interaction with aspects of nature in the theory's domain. These routes are independent in that each can be pursued without knowledge of the details or results of the alternative route. The approach accounts for the role of empirical results in evaluating theories without requiring that these results be theory?free or more certain than theoretical results. It also provides a basis for understanding the conditions under which a conflict between observation and theory can result in rejection of the observational result. (shrink)

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.