Experiments may not reveal their full import at the time that they are performed. The scientists who perform them usually are testing a specific hypothesis and quite often have specific expectations limiting the possible inferences that can be drawn from the experiment. Nonetheless, as Hacking has said, experiments have lives of their own. Those lives do not end with the initial report of the results and consequences of the experiment. Going back and rethinking the consequences of the experiment in a (...) new context, theoretical or empirical, has great merit as a strategy for investigation and for scientific problem analysis. I apply this analysis to the interplay between Fizeau's classic optical experiments and the building of special relativity. Einstein's understanding of the problems facing classical electrodynamics and optics, in part, was informed by Fizeau's 1851 experiments. However, between 1851 and 1905, Fizeau's experiments were duplicated and reinterpreted by a succession of scientists, including Hertz, Lorentz, and Michelson. Einstein's analysis of the consequences of the experiments is tied closely to this theoretical and experimental tradition. However, Einstein's own inferences from the experiments differ greatly from the inferences drawn by others in that tradition. (shrink)

In his book, Physical Relativity, Harvey Brown challenges the orthodox view that special relativity is preferable to those parts of Lorentz's classical ether theory it replaced because it revealed various phenomena that were given a dynamical explanation in Lorentz's theory to be purely kinematical. I want to defend this orthodoxy. The phenomena most commonly discussed in this context in the philosophical literature are length contraction and time dilation. I consider three other phenomena of this kind that played a role in (...) the early reception of special relativity in the physics literature: the Fresnel drag effect in the Fizeau experiment, the velocity dependence of electron mass in beta-ray deflection experiments by Kaufmann and others, and the delicately balanced torques on a moving charged capacitor in the Trouton-Noble experiment. I offer historical sketches of how Lorentz's dynamical explanations of these phenomena came to be replaced by their now standard kinematical explanations. I then take up the philosophical challenge posed by the work of Harvey Brown and Oliver Pooley and clarify how those kinematical explanations work. (shrink)

In his book, Physical Relativity, Harvey Brown challenges the orthodox view that special relativity is preferable to those parts of Lorentz's classical ether theory it replaced because it revealed various phenomena that were given a dynamical explanation in Lorentz's theory to be purely kinematical. I want to defend this orthodoxy. The phenomena most commonly discussed in this context in the philosophical literature are length contraction and time dilation. I consider three other phenomena of this kind that played a role in (...) the early reception of special relativity in the physics literature: the Fresnel drag effect in the Fizeau experiment, the velocity dependence of electron mass in beta-ray deflection experiments by Kaufmann and others, and the delicately balanced torques on a moving charged capacitor in the Trouton-Noble experiment. I offer historical sketches of how Lorentz's dynamical explanations of these phenomena came to be replaced by their now standard kinematical explanations. I then take up the philosophical challenge posed by the work of Harvey Brown and Oliver Pooley and clarify how those kinematical explanations work. (shrink)

Abstract.Einstein learned from the magnet and conductor thought experiment how to use field transformation laws to extend the covariance of Maxwell’s electrodynamics. If he persisted in his use of this device, he would have found that the theory cleaves into two Galilean covariant parts, each with different field transformation laws. The tension between the two parts reflects a failure not mentioned by Einstein: that the relativity of motion manifested by observables in the magnet and conductor thought experiment does not extend (...) to all observables in electrodynamics. An examination of Ritz’s work shows that Einstein’s early view could not have coincided with Ritz’s on an emission theory of light, but only with that of a conveniently reconstructed Ritz. One Ritz-like emission theory, attributed by Pauli to Ritz, proves to be a natural extension of the Galilean covariant part of Maxwell’s theory that happens also to accommodate the magnet and conductor thought experiment. Einstein’s famous chasing a light beam thought experiment fails as an objection to an ether-based, electrodynamical theory of light. However it would allow Einstein to formulate his general objections to all emission theories of light in a very sharp form. Einstein found two well known experimental results of 18th and 19th century optics compelling (Fizeau’s experiment, stellar aberration), while the accomplished Michelson-Morley experiment played no memorable role. I suggest they owe their importance to their providing a direct experimental grounding for Lorentz‘ local time, the precursor of Einstein’s relativity of simultaneity, and doing it essentially independently of electrodynamical theory. I attribute Einstein’s success to his determination to implement a principle of relativity in electrodynamics, but I urge that we not invest this stubbornness with any mystical prescience. (shrink)

In 1783 John Michell published a note entitled ‘On the Means of Discovering the Distance, Magnitude etc. of the Fixed Stars, in Consequence of the Diminution of the Velocity of their Light’, but it was Christian Doppler who in 1842 for the first time formulated the principle : If a source of sound or light is in motion relative to an observer, or an observer in motion relative to a source, the period of the waves received by the observer will (...) be different from the period of the waves emitted by the source. The acoustical Doppler principle was verified in 1845 by Buys-Ballot's experiments and by Ernst Mach ). H. Fizeau proposed to verify the optical Doppler principle by measuring the shift of lines in the spectra of stars . This was carried out by William Huggins , and H. C. Vogel and led to exact results in 1892. The Doppler effect with canal rays was shown by Johannes Stark in 1905. (shrink)

Einstein learned from the magnet and conductor thought experiments how to use field transformation laws to extend the covariance to Maxwell’s electrodynamics. If he persisted in his use of this device, he would have found that the theory cleaves into two Galilean covariant parts, each with different field transformation laws. The tension between the two parts reflects a failure not mentioned by Einstein: that the relativity of motion manifested by observables in the magnet and conductor thought experiment does not extend (...) to all observables in electrodynamics. An examination of Ritz’s work shows that Einstein’s early view could not have coincided with Ritz’s on an emission theory of light, but only with that of a conveniently reconstructed Ritz. One Ritz-like emission theory, attributed by Pauli to Ritz, proves to be a natural extension of the Galilean covariant part of Maxwell’s theory that happens also to accommodate the magnet and conductor thought experiment. Einstein's famous chasing a light beam thought experiment fails as an objection to an ether-based, electrodynamical theory of light. However it would allow Einstein to formulate his general objections to all emission theories of light in a very sharp form. Einstein found two well known experimental results of 18th and19th century optics compelling (Fizeau’s experiment, stellar aberration), while the accomplished Michelson-Morley experiment played no memorable role. I suggest they owe their importance to their providing a direct experimental grounding for Lorentz’ local time, the precursor of Einstein’s relativity of simultaneity, and do it essentially independently of electrodynamical theory. I attribute Einstein’s success to his determination to implement a principle of relativity in electrodynamics, but I urge that we not invest this stubbornness with any mystical prescience. (shrink)

An apparent inadequacy of the velocity addition theorem in handling a Fizeau (like) experiment beyond the resonance frequence is shown not to be a true failing. The proof consists in showing that the invariance of the signal velocity is unrelated to its maximality. Next, Lorentz transformations which connect frames moving with supersignal velocity to those of subsignal velocity are derived, taking a cue from the acoustic case. Methods are also suggested for laboratory verification of the theory.

Es importante destacar que cuando en la historia de la física se hace referencia al problema de si la luz se transmite de manera instantánea o si requiere de tiempo –que se abreviará aquí como el problema de la propagación sucesiva de la luz– siempre destacan ciertos personajes: por un lado, Armand Hippolyte Louis Fizeau y Jean Bernard León Foucault, quienes en el siglo XIX lograron medir por primera vez de forma precisa la velocidad de la luz; y por (...) otro, los astrónomos Ole Christensen Roemer y James Bradley, quienes en los siglos XVII y XVIII –respectivamente– fueron los primeros en dar una respuesta derivada de trabajos observacionales de que la luz sí requiere de tiempo en su transmisión, esto es, que su propagación es sucesiva. Entre estos nombres, aparece siempre de forma algo etérea Galileo Galilei como el primero que propuso un enfoque experimental para dar respuesta a esta pregunta. (shrink)

This paper warns against destructive effects of subjectivist thinking. Subjectivist accounts, as Alan Sokal exposed, promote a distorted view of scientific practice. For example, Einstein's 1905 special theory of relativity relied on data produced by Fizeau, a physicist trained in classical mechanics. Einstein's use of Fizeau's results shows that the ontological foundation of uncontroversial data transcends conventional speculations. Einstein's employment of Fizeau's results mitigates against ideas such as paradigm shifts and revolutionary science. Instead, the ontology of shared (...) horizons of fact remains largely unadulterated. The descriptions scientists use accommodate received view shifts, but the horizon of fact remains unimpeachably the same. The apt performance of science shows what it means to move further away from error. The only direction away from error is toward truth. To deny the reality of this directionality flies in the face of common sense and prudent science. (shrink)

This paper warns against destructive effects of subjectivist thinking. Subjectivist accounts, as Alan Sokal exposed, promote a distorted view of scientific practice. For example, Einstein's 1905 special theory of relativity relied on data produced by Fizeau, a physicist trained in classical mechanics. Einstein's use of Fizeau's results shows that the ontological foundation of uncontroversial data transcends conventional speculations. Einstein's employment of Fizeau's results mitigates against ideas such as paradigm shifts and revolutionary science. Instead, the ontology of shared (...) horizons of fact remains largely unadulterated. The descriptions scientists use accommodate received view shifts, but the horizon of fact remains unimpeachably the same. The apt performance of science shows what it means to move further away from error. The only direction away from error is toward truth. To deny the reality of this directionality flies in the face of common sense and prudent science. (shrink)

I defend the widely held view challenged by Harvey Brown in his recent book that special relativity is preferable to those parts of Lorentz’s electron theory it replaced because various phenomena that special relativity reveals to be of purely kinematical origin were given a dynamical explanation in Lorentz’s theory. The phenomena most commonly discussed in this context in the philosophical literature are length contraction and time dilation. I consider three other such phenomena that played a role in the early reception (...) of special relativity in the physics community: the Fresnel drag effect in the Fizeau experiment, the velocity dependence of electron mass in the -ray deflection.. (shrink)

in this paper i assess Pierre Duhem’s criticism of crucial experiments, and argue that we have reasons to vindicate their existence. i then analize the experiments carried out by Fizeau and Foucault in 1850, and criticize Duhem’s interpretation of their results. i contend that the results of crucial experiences can be described in terms that are neutral with respect to the competing theories. For that reason an experimental result is relatively stable and open to different interpretations in the light (...) of new theories. i conclude by distinguishing successful crucial experiments from decisive experiments. The former are meant to provide evidence that confirms one theory and disconfirms its rivals, but not necessarily to provide sufficient reasons for accepting or rejecting one of those theories. (shrink)

It is routinely assumed that Einstein discovered the relativity of simultaneity by thinking about how clocks can be synchronized by light signals, much in accord with the analysis he gave in his 1905 special relativity paper. Yet that is just supposition. We have no real evidence that it actually happened this way. In later recollections, Einstein stressed the importance of several thought experiments in the thinking that led up to the final theory. They include his chasing a light beam thought (...) experiment and his magnet and conductor thought experiment. They do not include thought experiments on clocks and their synchronization. My goal here is to show that other pathways to the relativity of simultaneity are quite plausible. In several places Einstein stressed the importance in his discovery of special relativity of stellar aberration and Fizeau's measurement of the speed of light in moving water. The results can be seen as direct observational expressions of the relativity of simultaneity, if one knows how to read them. I will suggest that, thanks to his knowledge of Lorentz's 1895 Versuch, Einstein did know how to read them, and that it is quite possible that these observations first led Einstein to the relativity of simultaneity. (shrink)