Une analyse des concepts d'heuristique et de tolérance méthodologique développée par Lakatos, basée sur l'article "Falsification et méthodologie des programmes de recherche scientifique", publié pour la première fois en 1970, puis dans l'ouvrage La méthodologie des programmes de recherche scientifique, volume I. J'ai analysé dans ce texte l'exemplifiant de l'auteur pour le programme de recherche de l'émission de lumière (en physique quantique au début). Un exemple détaillé des concepts est présenté par Lakatos dans la section "Effet de Newton sur les (...) normes scientifiques" du même livre. J'ai également fait souvent référence au livre Preuves et Réfutations, publié par Lakatos en 1976, dans lequel il expose sa vision heuristique par une application directe à l'évolution des mathématiques. J'ai également fait référence à des articles d'autres auteurs pour l'analyse des deux concepts dans la vision de Lakatos. SOMMAIRE: Abstract 1 Vue d'ensemble 1.1 Le falsificationnisme dogmatique (ou naturaliste) 1.2 La falsification méthodologique 1.3 La falsification méthodologique sophistiquée 2. La tolérance méthodologique 3 L'heuristique 3.1 Heuristique négative : le « noyau dur » du programme 3.2 L'heuristique positive : la « ceinture de protection » du programme 3.3 Bohr : un exemple de programme de recherche 3.4 Preuves et Réfutations 4 Conclusions Bibliographie DOI: 10.13140/RG.2.2.30348.46729 . (shrink)

Magnus and Callender argue that we ought to focus on retail arguments, which are arguments regarding the existence of particular kinds of theoretical entities, as opposed to theoretical entities in general. However, scientists are the ones who put forward retail arguments, and it’s unclear how philosophers can engage with such arguments. We argue that philosophers can engage with retail arguments by providing criteria that they must satisfy in order to demonstrate the existence of theoretical entities. We put forward experimental individuation (...) as such a criterion---when scientists experimentally individuate an entity, a realist conclusion about that entity is warranted. (shrink)

An early, very preliminary edition of this book was circulated in 1962 under the title Set-theoretical Structures in Science. There are many reasons for maintaining that such structures play a role in the philosophy of science. Perhaps the best is that they provide the right setting for investigating problems of representation and invariance in any systematic part of science, past or present. Examples are easy to cite. Sophisticated analysis of the nature of representation in perception is to be found already (...) in Plato and Aristotle. One of the great intellectual triumphs of the nineteenth century was the mechanical explanation of such familiar concepts as temperature and pressure by their representation in terms of the motion of particles. A more disturbing change of viewpoint was the realization at the beginning of the twentieth century that the separate invariant properties of space and time must be replaced by the space-time invariants of Einstein's special relativity. Another example, the focus of the longest chapter in this book, is controversy extending over several centuries on the proper representation of probability. The six major positions on this question are critically examined. Topics covered in other chapters include an unusually detailed treatment of theoretical and experimental work on visual space, the two senses of invariance represented by weak and strong reversibility of causal processes, and the representation of hidden variables in quantum mechanics. The final chapter concentrates on different kinds of representations of language, concluding with some empirical results on brain-wave representations of words and sentences. (shrink)

This inaugural handbook documents the distinctive research field that utilizes history and philosophy in investigation of theoretical, curricular and pedagogical issues in the teaching of science and mathematics. It is contributed to by 130 researchers from 30 countries; it provides a logically structured, fully referenced guide to the ways in which science and mathematics education is, informed by the history and philosophy of these disciplines, as well as by the philosophy of education more generally. The first handbook to cover the (...) field, it lays down a much-needed marker of progress to date and provides a platform for informed and coherent future analysis and research of the subject. -/- The publication comes at a time of heightened worldwide concern over the standard of science and mathematics education, attended by fierce debate over how best to reform curricula and enliven student engagement in the subjects There is a growing recognition among educators and policy makers that the learning of science must dovetail with learning about science; this handbook is uniquely positioned as a locus for the discussion. -/- The handbook features sections on pedagogical, theoretical, national, and biographical research, setting the literature of each tradition in its historical context. Each chapter engages in an assessment of the strengths and weakness of the research addressed, and suggests potentially fruitful avenues of future research. A key element of the handbook’s broader analytical framework is its identification and examination of unnoticed philosophical assumptions in science and mathematics research. It reminds readers at a crucial juncture that there has been a long and rich tradition of historical and philosophical engagements with science and mathematics teaching, and that lessons can be learnt from these engagements for the resolution of current theoretical, curricular and pedagogical questions that face teachers and administrators. (shrink)

SummaryFaraday's concept of force is described by six assumptions. These specify a concept that is quite distinct from ‘mechanical’ conceptions of his contemporaries and interpreters. Analysis of the role of these assumptions clarifies Faraday's weighting of experimental evidence and shows how closely-linked Faraday's chemistry and physics were to his theology. It is argued that Faraday was unable to secularize his concept of force by breaking the ties between his physics and his theology of nature. Examination of his basic assumptions also (...) explains Faraday's failure to quantify his principle of conservation of force, his rejection of mechanical concepts of force and energy, and his early attempt to develop a wave-model for the conversion and transmission of electricity, magnetism, light and heat. (shrink)

A prized property of theories of all kinds is that of generality, of applicability or least relevance to a wide range of circumstances and situations. The purpose of this article is to present a pair of distinctions that suggest that three kinds of generality are to be found in mathematics and logics, not only at some particular period but especially in developments that take place over time: ‘omnipresent’ and ‘multipresent’ theories, and ‘ubiquitous’ notions that form dependent parts, or moments, of (...) theories. The category of ‘facets’ is also introduced, primarily to assess the roles of diagrams and notations in these two disciplines. Various consequences are explored, starting with means of developing applied mathematics, and then reconsidering several established ways of elaborating or appraising theories, such as analogising, revolutions, abstraction, unification, reduction and axiomatisation. The influence of theories already in place upon theory-building is emphasised. The roles in both mathematics and logics of set theory, abstract algebras, metamathematics, and model theory are assessed, along with the different relationships between the two disciplines adopted in algebraic logic and in mathematical logic. Finally, the issue of monism versus pluralism in these two disciplines is rehearsed, and some suggestions are made about the special character of mathematical and logical knowledge, and also the differences between them. Since the article is basically an exercise in historiography, historical examples and case studies are described or noted throughout. (shrink)

This article deals with empty spacetime and the question of its physical reality. By “empty spacetime” we mean a collection of bare spacetime points, the remains of ridding spacetime of all matter and fields. We ask whether these geometric objects—themselves intrinsic to the concept of field—might be observable through some physical test. By taking quantum-mechanical notions into account, we challenge the negative conclusion drawn from the diffeomorphism invariance postulate of general relativity, and we propose new foundational ideas regarding the possible (...) observation—as well as conceptual overthrow—of this geometric ether. (shrink)

In this article, against the background of a notion of ‘assembled’ truth, the evolutionary progressiveness of a theory is suggested as novel and promising explanation for the success of science. A new version of realism in science, referred to as ‘naturalised realism’ is outlined. Naturalised realism is ‘fallibilist’ in the unique sense that it captures and mimics the self-corrective core of scientific knowledge and its progress. It is argued that naturalised realism disarms Kyle Stanford’s anti-realist ‘new induction’ threats by showing (...) that ‘explanationism’ and his ‘epistemic instrumentalism’ are just two positions among many on a constantly evolving continuum of options between instrumentalism and full-blown realism. In particular it is demonstrated that not only can naturalised realism redefine the terms of realist debate in such a way that no talk of miracles need enter the debate, but it also promises interesting defenses against inductive- and under-determination-based anti-realist arguments. (shrink)

Modern readers turning to Einstein’s famous 1905 paper on special relativity may not find what they expect. Its title, “On the electrodynamics of moving bodies,” gives no inkling that it will develop an account of space and time that will topple Newton’s system. Even its first paragraph just calls to mind an elementary experimental result due to Faraday concerning the interaction of a magnet and conductor. Only then does Einstein get down to the business of space and time and lay (...) out a new theory in which rapidly moving rods shrink and clocks slow and the speed of light becomes an impassable barrier. This special theory of relativity has a central place in modern physics. As the first of the modern theories, it provides the foundation for particle physics and for Einstein’s general theory of relativity; and it is the last point of agreement between them. It has also received considerable attention outside physics. It is the first port of call for philosophers and other thinkers, seeking to understand what Einstein did and why it changed everything. It is often also their last port. The theory is arresting enough to demand serious reflection and, unlike quantum theory and general relativity, its essential content can be grasped fully by someone merely with a command of simple algebra. It contains Einstein’s analysis of simultaneity, probably the most celebrated conceptual analysis of the century. (shrink)

In October 1924, The Physical Review, a relatively minor journal at the time, published a remarkable two-part paper by John H. Van Vleck, working in virtual isolation at the University of Minnesota. Van Vleck used Bohr's correspondence principle and Einstein's quantum theory of radiation to find quantum formulae for the emission, absorption, and dispersion of radiation. The paper is similar but in many ways superior to the well-known paper by Kramers and Heisenberg published the following year that is widely credited (...) to have led directly to Heisenberg's Umdeutung paper. As such, it clearly shows how strongly the discovery of matrix mechanics depended on earlier work on the application of the correspondence principle to the interaction of matter and radiation. (shrink)

The first models for an electromagnetic theory of dispersion are presented and an attempt is made to demonstrate the important role played by study of this phenomenon at the end of the nineteenth century. As well as indicating the need to have a better understanding of the microscopic properties of matter, dispersion also contributed to the discussion over the nature of X-rays and was fundamental for introduction of Lorentz's electron theory.

Le modèle atomique de Bohr a été l'un des exemples les plus brillants de la méthodologie des programmes de recherche d'Imre Lakatos. Les grandes lignes du programme de recherche de Bohr (Bohr 1913) peuvent être caractérisées par : 1. Le problème initial ; 2. Ses heuristiques négatives et positives ; 3. Les problèmes qu'il a tenté de résoudre au cours du développement ; 4. Son point de dégénérescence (point de saturation) et, enfin, 5. Le programme par lequel il a été (...) remplacé. 10.13140/RG.2.2.21718.68166 . (shrink)

Pentru a analiza conceptele de euristica și toleranță metodologică dezvoltate de Lakatos, m-am concentrat pe secțiunea ”Falsification and the methodology of scientific research programmes”, publicată pentru prima dată ca articol în 1970 și apoi în cartea The methodology of scientific research programmes, Volume I (Lakatos 1978). Am analizat, în acest text, exemplificarea autorului pentru programul de cercetare al emisiei de lumină (în fizica cuantică timpurie) al lui Bohr. O exemplificare detaliată a conceptelor este prezentată de Lakatos în secțiunea ”Newton's effect (...) on scientific standards” din aceeași carte. De asemenea, am făcut dese referiri la cartea Proofs and Refutations (Lakatos 1976) publicată de Lakatos în 1976, în care expune viziunea sa euristică printr-o aplicare directă la evoluția matematicii, și am apelat și la articole ale altor autori pentru analiza celor două concepte în viziunea lui Lakatos. -/- Cuvinte cheie: Imre Lakatos, euristica, toleranța metodologică -/- CUPRINS -/- Abstract 1 Prezentarea generală 1.1 Falsificaţionismul dogmatic (sau naturalist) 1.2 Falsificarea metodologică 1.3 Falsificaţionismul metodologic sofisticat 2 Toleranţa metodologică 3 Euristica 3.1 Euristica negativă: "nucleul dur” al programului 3.2 Euristica pozitivă: "centura de protecţie" a programului 3.3 Bohr: un exemplu de program de cercetare 3.4 Proofs and Refutations 4 Concluzii Bibliografie -/- DOI: 10.13140/RG.2.2.35405.28649. (shrink)

The aether, proposed to be a subtle primordial substance, was once thought to permeate all space and provide a substrate through which electromagnetic waves, such as light, traveled. It is a powerful explanatory concept that has roots in ancient indigenous knowledge and helped unify our understanding of the physical world for centuries. The Michelson-Morley experiment is often credited as being the death blow to aether, but this is not exactly so. These experimental results were not nil, but showed approximately 25% (...) of the expected 30m/s speed of an "aether wind" from Earth orbiting the Sun. The aether was abandoned largely because of Einstein's Special Relativity Theory, which contradicts an absolute frame of reference. Nonetheless, Einstein came to accept a new version of the aether to explain parts of his famous theory of General Relativity. Although the static aether of the 19th century was abandoned, with the advent of quantum mechanics, new dynamic models of space were developed. Space was viewed as a quantum plenum full of energetic potential resulting from Planck's blackbody radiation. Indeed, space has measurable physical properties that imply the existence of a subtle substance herein called the "neo-aether." Matter can be considered a unique dynamic state of the "neo-aether." A rudimentary consciousness may be rooted in this deep substratum of existence. Historical highlights of the aether concept and the "neo-aether" are described here. There is the Akasha of Vedic philosophy; the luminiferous aether of Huygens; Maxwell's theory of molecular vortices; the zero point energy of quantum theory; the dark energy of cosmology; the quantum potential of Bohm; and metaphysical perspectives. Whereas 20th century physics was largely caught up in mathematical verbiage, the "neo-aether" is a physical model that provides causal explanations of observed phenomena including non-locality and electromagnetic wave propagation through space. One implication of the "neo-aether" is the possibility of a unified field theory in which particles, fields, and even sentience originates. (shrink)

A draft of a possible comparison between the use made of mathematics in classical field theories and in quantum mechanics is presented. Hilbert’s space formalism, although not only elegant and powerful but intuitive as well, does not give us a spatio-temporal representation of physical events. The picture of the electromagnetic field as an entity which is real in itself– i.e., as a wave without support – fostered by the emergence of special relativity can be seen as the first step, favored (...) by many physicists and philosophers, of a gradual “escape” from intuition into a purely mathematical representation of the external world. After the introduction, in recent theoretical physics, of fiber bundle formalism the classical notion of field acquires a new spatio-temporal intuitiveness. This intuitiveness is clearly foreshadowed in the Kantian and Meinongian analysis of the notion of magnitude. At the end of the paper we show that, contrary to what happens in quantum mechanics, mathematics plays a truly explicative role in general relativity, without any loss of spatio-temporal intuitiveness. (shrink)

Astronomical observations of redshifts and the cosmic background radiation show that there is a local frame of reference relative to which the solar system has a well-defined velocity. Also, in cosmology the cosmological principle implies the existence of cosmic time and unique local reference frames at all spacetime points. On the other hand, in a fundamental postulate, the theory of special relativity excludes the possibility of the velocity of the Earth from entering into theories of local physics.The theory put forward (...) in this paper resolves this conflict between local physics and cosmology. The theory retains the essential ingredient of the mathematical structure of special relativity, namely covariance under the Lorentz symmetry group, but changes radically the interpretation of the physical significance of the Lorentz transformation. The theory is based on the postulate that in free space the fundamental interactions in physics are propagated with constant velocity with respect to the local rest frame. In Minkowski spacetime the local rest frame of reference defines a unique time axis and consequently a unique three-dimensional spatial hyperplane. One particularly important result of this is that the theory includes the classical notion of simultaneity. From the fundamental postulate it follows that the equations of local physics, when expressed in terms of the rest frame coordinate system, must be covariant under the Lorentz symmetry group. By the identification of the local rest frame with the (unique) cosmological local reference frame the two theories become mutually consistent.The effects of the motion of the Earth on laboratory experiments are discussed. It is pointed out that existing experimental data do not discriminate between the present theory and that of special relativity: a proposal for an experimental test is made. (shrink)

We present the theory, the experimental evidence and fundamental physical consequences concerning the existence of families of undistorted progressive waves (UPWs) of arbitrary speeds 0≤ϑ<∞, which are solutions of the homogeneuous wave equation, the Maxwell equations, and Dirac, Weyl, and Klein-Gordon equations.

Many realists have maintained that the success of scientific theories can be explained only if they may be regarded as approximately true. Laurens Laudan has in turn contended that a necessary condition for a theory's being approximately true is that its central terms refer, and since many successful theories of the past have employed central terms which we now understand to be non-referential, realism cannot explain their success. The present paper argues that a realist can adopt a view of reference (...) according to which a theory might plausibly be said to be approximately true even though its central terms do not refer, or alternatively, he may construe reference in such a way as to assign reference to a range of successful older theories which includes Laudan's purported counterexamples. (shrink)

This paper aims to defend the use of the notion of experimental individuation, which has recently been developed by Ruey-Lin Chen, as a criterion for the reality of theoretical entities. In short, when scientists experimentally individuate an entity, a realist conclusion about that entity is warranted. We embed this claim regarding experimental individuation within a framework that allows for other criteria of reality. And we understand so-called retail arguments regarding the reality of a particular theoretical entity as arguments that concern (...) choosing an appropriate criterion of reality for that entity and determining whether the relevant first-order scientific evidence satisfies that criterion. We argue that such retail arguments are philosophical because defending criteria of reality, and showing that they are or are not satisfied in particular cases, involves work that is distinctively philosophical. And we illustrate this philosophical work by applying our criterion of experimental individuation to three historical cases: Davy’s potassium, Lavoisier’s muriatic radical, and Thomson’s electrified particles. (shrink)

By mass-energy equivalence, the gravitational field has a relativistic mass density proportional to its energy density. I seek to better understand this mass of the gravitational field by asking whether it plays three traditional roles of mass: the role in conservation of mass, the inertial role, and the role as source for gravitation. The difficult case of general relativity is compared to the more straightforward cases of Newtonian gravity and electromagnetism by way of gravitoelectromagnetism, an intermediate theory of gravity that (...) resembles electromagnetism. (shrink)

It is shown that the Maxwell-Lorentz equations can be deduced from the law of Biot-Savart by simply performing some theoretical experimentations.

Physics seems to tell us that there are four fundamental force-fields in nature: the gravitational, the electromagnetic, the weak, and the strong (or interactions). But it also seems to tell us that gravity cannot possibly be a force-field, in the same sense as the other three are. And yet the search for a grand unification of all four force-fields is today one of the hottest pursuits. Is this the result of a simple confusion? This article aims at clarifying this situation (...) by (i) reviewing the gauge-field programme and its conception of unification of force-fields, (ii) examining the various attempts at a gauge theory of gravity, and (iii) articulating the nature of "gauging" and using it to explain the difference between gravity and the other force-fields. (shrink)

This paper proposes an account of natural analogy in scientific theorizing via Mary Hesse’s original understanding of analogical reasoning. Starting with discussing Hesse’s examples and her symbolic scheme, I argue that the traditional distinction between the type of formal analogy and the type of material analogy should be abandoned. All analogies in theorizing, that are both formal and material, contain a set of pretheoretic associations and a theoretic structure between two analogues. I thus provide a new interpretation of Hesse’s symbolic (...) scheme to reveal the pretheoretical and the structural dimensions of analogy and further illustrate the account of natural analogy by applying it to the history of the construction of Coulomb’s law, which is traditionally seen as a typical case of formal analogy, arguing that pretheoretic associations as well as a theoretic structure play a necessary role in this case. In the final part of this paper, I argue that the account of natural analogy is preferable to Dedre Gentner’s structural mapping theory. (shrink)

In October 1924, The Physical Review, a relatively minor journal at the time, published a remarkable two-part paper by John H. Van Vleck, working in virtual isolation at the University of Minnesota. Using Bohr’s correspondence principle and Einstein’s quantum theory of radiation along with advanced techniques from classical mechanics, Van Vleck showed that quantum formulae for emission, absorption, and dispersion of radiation merge with their classical counterparts in the limit of high quantum numbers. For modern readers Van Vleck’s paper is (...) much easier to follow than the famous paper by Kramers and Heisenberg on dispersion theory, which covers similar terrain and is widely credited to have led directly to Heisenberg’s Umdeutung paper. This makes Van Vleck’s paper extremely valuable for the reconstruction of the genesis of matrix mechanics. It also makes it tempting to ask why Van Vleck did not take the next step and develop matrix mechanics himself. (shrink)

The thesis of this article is that the nature of probability is centered on its formal properties, not on any of its standard interpretations. Section 2 is a survey of Bayesian applications. Section 3 focuses on two examples from physics that seem as completely objective as other physical concepts. Section 4 compares the conflict between subjective Bayesians and objectivists about probability to the earlier strident conflict in physics about the nature of force. Section 5 outlines a pragmatic approach to the (...) various interpretations of probability. Finally, Sect. 6 argues that the essential formal nature of probability is expressed in the standard axioms, but more explicit attention should be given to the concept of randomness. (shrink)

It is argued that the way towards understanding the experiments with visible light which purport to exhibit nonlocality lies in a return to the wave theory of light. A connection is also indicated between the present-day photon description and the pre-wave-theory corpuscular description, and hence we see that, essentially, the problem of nonlocality in physics was solved nearly two centuries ago by Young and Fresnel.

Naturalists tell us to rely on what science tells about the world and to eschew aprioristic philosophy. But foundational physics relies internally on modes of thinking that can only be called philosophical, and philosophical arguments rely upon what can only be called scientific inference. So what, then, could the naturalistic thesis really amount to?

Prompted by Hasok Chang’s conception of the history and philosophy of science (HPS) as the continuation of science by other means, I examine the possibility of obtaining scientific knowledge through philosophical criticism and reflection, in the light of four historical cases, concerning (i) the role of absolute space in Newtonian dynamics, (ii) the purported contraction of rods and retardation of clocks in Special Relativity, (iii) the reality of the electromagnetic ether, and (iv) the so-called problem of time’s arrow. In all (...) four cases it is clear that a better understanding of such matters can be achieved —and has been achieved— through conceptual analysis. On the other hand, however, it would seem that this kind of advance has more to do with philosophical questions in science than with narrowly scientific questions. Hence, if HPS in effect continues the work of science by other means, it could well be doing it for other ends than those that working scientists ordinarily have in mind. (shrink)

: Armed with a photometer originally designed for evaluating telescopes, Richard Potter in the early 1830s measured the re(integral)ective power of metallic and glass mirrors. Because he found significant discrepancies between his measurements and Fresnel's predictions, Potter developed doubts concerning the wave theory. However, Potter's measurements were colored by a peculiar procedure. In order to protect the sensitivity of the eye, Potter made certain approximations in the measuring process, which exaggerated the discrepancies between the theory and the data. Potter's measurements (...) received strong criticisms from wave theorists, not because they felt they needed to defend their theory, but because they believed that Potter was wrong in using the eye as an essential apparatus in the experiments. Potter's photometric measurements and the subsequent debate reveal the existence of two incompatible sets of measuring procedures, each of which consisted of a body of practices concerning how photometric instruments should be used properly. In the debate, the differences regarding measuring procedures shaped the participant's judgments of experimental evidence and eventually their evaluations of the optical theories. (shrink)

Time is analyzed by considering the actual setup of clock system within the four-dimensional framework. We find that both relativistic time and universal time can be embedded in such a symmetry framework. Although Poincaré and Einstein both understood the meaning of Lorentz's local time in terms of sending light signals to calibrate clocks, they differed on a basic point: Einstein believed local time to be the necessary and unique time, while Poincaré admitted flexibility in the definitions of time and regarded (...) local time as only a convention. The results of our analysis shed light on Poincaré's original idea concerning conventions of time and provide the conceptual basis for the formulation of a new four-dimensional symmetry with a universal time. We demonstrate that the one-way speeds of light measured by stable atomic clocks in rockets may not be isotropic, in contrast to the two-way speeds of light. Furthermore, atomic clocks can be used to set up a clock system which reads a universal (but not absolute) time. (shrink)

It is argued that the so-called “absolute space-time theory” is inconsistent, in disagreement with some astronomical observations, and improperly titled.

The polarity of light and dark in the treatment of the Newtonian spectrum and the inverse spectrum is studied further and the validity of heterogeneity of light and darkness in relation to Goethe’s views is examined. In order to clarify the reality of the “darkness rays”, theexperimentum crucisis re-evaluated. It is shown that the commonly accepted analysis contains assumptions in the choice of the spectrum and background, which mask the inherent dynamic of the spectrum. The relation between colour and wavelength (...) is re-examined with respect to the immutability and specific refrangibility of colour. It is then shown that both these properties are approximations that apply under the specific conditions that have later become standardized in spectroscopy, leading to a consensus regarding the relation of wavelength to colours of one particular spectrum. This consensus has resulted in the study of colour diverging into spectroscopy and colour physiology. As an alternative, the basis of the dichotomy postulated by Müller is studied, leading to the realization that the resolution of this dichotomy was begun by Goethe with the idea of turbidity. A further study shows that turbidity resolves the apparent incompatibility of light and dark. (shrink)

The history of the luminiferous ether is sketched with a view to ascertaining what factors may have kept this idea alive until 1905, when Einstein declared it superfluous.

We present a mechanical model of a quasi-elastic body which reproduces Maxwell’s equations with charges and currents. Major criticism against mechanical models of electrodynamics is that any presence of charges in the known models appears to violate the continuity equation of the aether and it remains a mystery as to where the aether goes and whence it comes. We propose a solution to the mystery—in the present model the aether is always conserved. Interestingly it turns out that the charge velocity (...) coincides with the aether velocity. In other words, the charges appear to be part of the aether itself. We interpret the electric field as the flux of the aether and the magnetic field as the torque per unit volume. In addition we show that the model is consistent with the theory of relativity, provided that we use Lorentz–Poincare interpretation of relativity theory. We make a statistical-mechanical interpretation of the Lorentz transformations. It turns out that the length of a body is contracted by the electromagnetic field which the molecules of this same body produce. This self-interaction causes also delay of all the processes and clock-dilation results. We prove this by investigating the probability distribution for a gas of self-interacting particles. We can easily extend this analysis even to elementary particles. (shrink)

In an article published recently in this journal, one of us reconstructed how in 1899 J. J. Thomson, after having measured the mass-to-charge ratio of the corpuscle , achieved a measurement of its charge and consequently an estimate of its mass, obtaining in this manner ‘direct proof of the existence of particles smaller than the hydrogen atom’. In this paper, starting with an analysis of Zeeman's first measurements on the widening of spectral lines in a magnetic field, we show that (...) the existence of masses smaller than the atom was already a matter of discussion in early 1897, and that a qualitative estimate of the mass of the electron was made even before Thomson's measurements in 1899. In this process an important role was played by a research programme on the structure of matter carried out by Stoney in the latter part of the nineteenth century. This had in many aspects anticipated Zeeman's experimental observations, and its conclusions were in part formalized in the so-called Larmor theorem. (shrink)

Unipolar induction, discovered in 1832 by Michael Faraday, is the case of electromagnetic induction in which a conductor and magnet are in relative rotatory motion. Attempts by scientists and engineers in the nineteenth and twentieth centuries to understand unipolar induction by using magnetic lines of force displayed striking national differences that influenced where the first largescale unipolar dynamo was built. This episode is described, as well as the effect of unipolar induction on Albert Einstein's thinking toward the special theory of (...) relativity, in sections 1–6. The analysis of electromagnetic induction in cases where the source of the magnetic field is in motion relative to the conductor is provided in sections 7–9. (shrink)

(1988). The explanative recourse to realism. International Studies in the Philosophy of Science: Vol. 3, No. 1, pp. 2-18. doi: 10.1080/02698598808573321.