The objective of this article is to provide a formalism to deal with the special theory of relativity (STR, in short) as riewed by Reichenbach, according to which STR involves an ineradicableconventionality of simultaneity. One of the two postulates of STR asserts that, in empty space, the one-way speed of light relative to inertial frames is constant. Experimental evidence, however, is related to the constancy of the round-trip speed of light and has no bearing on one-way speeds. Following Reichenbach's viewpoint, (...) we relax the second postulate of STR, abandoning the constancy of the one-way speed of light to the more realistic one asserting the constancy of the round-trip speed of light. This, in turn, results in a formalism to deal with Reichenbach's special theory of relativity (RSTR, in short) in which the two one-way speeds of light in empty space, C±, in the two senses of a round-trip are arbitrarily selected in such a way that their harmonic mean is the measurable round-trip speed of light, c. Experimentally, RSTR and STR are indistinguishable and, hence, represent the same physical theory. It is only the formalism that we use to deal with STR which is extended in RSTR to accommodate the immeasurability of one-way velocities. The usefulness of the proposed formalism to study special relativity is demonstrated. (shrink)

Debido a la historicidad de la razón, más que inventariar sus principales conceptos en un momento dado nos interesa estudiar el proceso de su formación y fijación. En este artículo se ilustra ese proceso con ejemplos tomados de la historia de la física. El primer ejemplo concierne a la subordinación en el siglo XVII de los fenómenos archiconocidos de la caída libre y el movimiento de los planetas a un concepto nuevo; los restantes, tomados de la electrodinámica del siglo XIX (...) y la microfísica y la cosmología del siglo XX, ilustran el juego mutuo de tales conceptos con novedades empíricas que en algunos casos los provocan, en otros los realizan. (shrink)

This paper has three goals. The first goal is to work out the difference between literal ceteris paribus laws in the sense of “all others being equal” and ceteris rectis “laws” in the sense of “all others being right”. While cp laws involve a universal quantification, cr generalizations involve an existential quantification over the values of the remainder variables Z. As a result, the two differ crucially in their confirmability and lawlikeness. The second goal is to provide a classification of (...) different kinds of cr generalizations, including certain transition cases between cr generalizations and cp laws. The third goal is to work out what cp laws and all kinds of cr assertions have in common: they figure as an information source for assertions of causal influence between variables. (shrink)

We explore the mathematical structure and the physical implications of a general four-dimensional symmetry framework which is consistent with the Poincaré—Einstein principle of relativity for physical laws and with experiments. In particular, we discuss a four-dimensional framework in which all observers in different frames use one and the same grid of clocks. The general framework includes special relativity and a recently proposed new four-dimensional symmetry with a nonuniversal light speed as two special simple cases. The connection between the properties of (...) light propagation and the convention concerning clock systems is also discussed, and is seen to be nonunique within the four-dimensional framework. (shrink)

The structures of space and time associated with various four-dimensional symmetries are constructed and examined. It is interesting that some of these four-dimensional symmetries are compatible with the existence of an aether in the Einstein sense. There are two classes of infinitely many four-dimensional symmetries that cannot be ruled out by previous experiments. We discuss some laser experiments that test these two classes of four-dimensional symmetries. An interesting connection between the nonclassical aether and gravity through the equality of inertial and (...) gravitational mass is explored. (shrink)

We propose a new picture of nature in which there are only two fundamental universal constantsè ē (≡e/c) andh(≡ħ/c). Our theory is developed within the framework of a new four-dimensional symmetry which is constructed on the basis of the Poincaré-Einstein principle of relativity for the laws of physics and the Newtonian concept of time. We obtain a new space-light transformation law, a velocity-addition law, and so on. In this symmetry scheme, the speed of light is constant and is completely relative. (...) The new theory is logically self-consistent, and it moreover is in agreement with all previously established experimental facts, such as the “lifetime dilatation” of unstable particles, the Michelson-Morley experiment, etc. There is a difference relative to the usual theory, though, in that our theory predicts a new law for the Dopplerfrequency shift, which can be tested experimentally by measuring the second-order frequency shift. (shrink)

In this paper I concentrate on the dynamic aspects of the special theory of relativity (in the non-Minkowski formalism), and not on the kinematic part of the story as is usually done. Following up the dynamic story leads to a new point of view as to Poincare's important role in the development of special relativity. Much of Poincare's dynamic work did not enter into Einstein's 1905 theory, since Einstein was mainly occupied with kinematics. However, the dynamic part is most fundamental (...) in the development of the special theory of relativity after 1905. In this paper I consider the main developments of relativistic dynamics in which I demonstrate that much response to Poincare's dynamic research can be found. I argue that Poincare's dynamic work assisted in departing from Einstein's electrodynamic theory towards relativistic dynamics (independent of electrodynamics). (shrink)

This study considers the short list of Nature of Science features frequently published and widely known in the science education discourse. It is argued that these features were oversimplified and a refinement of the claims may enrich or sometimes reverse them. The analysis shows the need to address the range of variation in each particular aspect of NOS and to illustrate these variations with actual events from the history of science in order to adequately present the subject. Another implication of (...) the proposal is the highlighting of the central role of science educators who, facing various strong claims of researchers in education and philosophy of science, often have difficulty in making a choice of what to teach about NOS. It is suggested that a representative variation with regard to the traditional NOS claims may be appropriate for a genuine understanding of the subject. In that, using the discipline-culture structure of the fundamental theories of physics and addressing the plurality of scientific methods may be helpful in the actual teaching and learning of NOS. (shrink)

Recent ?dynamical? approaches to relativity by Harvey Brown and his colleagues have used John Bell's own solution to a problem in relativity which has in the past sometimes been called ?Bell's spaceships paradox?, in a central way. This paper examines solutions to this problem in greater detail and from a broader philosophical perspective than Brown et al. offer. It also analyses the well-known analogy between special relativity and classical thermodynamics. This analysis leads to the sceptical conclusion that Bell's solution yields (...) neither new philosophical insights concerning the foundations of relativity nor differential support for a specific view concerning the existence of space-time. (shrink)

Einstein claimed that the fundamental dynamical insight of special relativity was the equivalence of mass and energy. I disagree. Not only are mass and energy not equivalent but talk of such equivalence obscures the real dynamical insight of special relativity, which concerns the nature of 4-forces and interactions more generally. In this paper I present and defend a new ontology of special relativistic particle dynamics that makes this insight perspicuous and I explain how alleged cases of mass–energy conversion can be (...) accommodated within that ontology. (shrink)

We examine the process of the emission of light from an atom that is in a relative translational motion with respect to the medium at rest in which the electromagnetic excitations propagate. The effect of Lorentz contraction of the of electron orbits on the emitted frequency is incorporated in the Rydberg formula, as well as the emitter’s Doppler effect is acknowledged. The result is that the frequency of the emitted light is modified by a factor that is identical with what (...) is called the ‘relativistic Doppler effect’. The new emission formula is applied for reinterpretation of the Ives-Stilwell experiment and shown that within the second order of approximation with respect to the speeds of the atom and the ‘absolute speed’ (Earth’s speed relative to the medium), the absolute motion does not affect the interference. The expression for the modification of the frequency involves both a first and a second-order term with respect to the speed of the atoms in the cathode tube. The latter turns out to be quantitatively the same as if the time would have changed its rate in the frame moving with the atoms. Thus, a new interpretation of the results of this famous experiment is provided without stipulating time dilation. (shrink)

A new vectorial representation for the successive Lorentz transformations has recently been proved very convenient to achieve a straightforward treatment of the Thomas rotation effect. Such a representation rests on equivalent forms for the pure Lorentz transformation and SLT whose physical meaning escaped us. The present paper fills this gap in by showing that those equivalent forms could represent appropriate world lines, lines and planes of simultaneity. Those geometric elements are particularly convenient to build up two new graphical representations for (...) the SLT: the first rests on that equivalent form for the SLT, while the second takes the SLT as a PLT preceded or followed by a Thomas rotation and uses the equivalent form for the PLT. As an application, the SLT Lorentz contraction formulas are derived for the first time. The dependence of the SLTLC on the Thomas rotation is put in evidence. The SLTLC along directions transverse and parallel to the composite velocity is studied. Original SLT Minkowski diagrams are given for the first time. (shrink)

By a comparison between Maxwell's electrodynamics classically interpreted (MT) and relativistic electrodynamics (RED), this paper discusses whether the “asymmetries” in MT mentioned by A. Einstein in his 1905 relativity paper are only of a conceptual nature or rather involve specific empirical claims. It is shown that in fact MT predicts strongly asymmetric behaviour for very simple interactions, and an analysis is made of the extent of the “symmetry” achieved by means of relativistic postulates. A “low” velocity experiment is suggested which (...) could provide another test of the accuracy of RED with respect to MT. (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)

Las máquinas aceleradas de Turing (ATMs) son dispositivos capaces de ejecutar súper-tareas. Sin embargo, el simple ejercicio de definirlas ha generado varias paradojas. En el presente artículo se definirán las nociones de súper-tarea y ATM de manera exhaustiva y se aclarará qué debe entenderse en un contexto lógico-formal cuando se pregunta por la existencia de un objeto. A partir de la distinción entre posibilidades lógicas y físicas se disolverán las paradojas y se concluirá que las ATMs son posibles y existen (...) como objetos abstractos. (shrink)

The Special Theory of Relativity (STR) holds sway as a theory of time due to its apparently successful predictive structure regarding time-related phenomena such as the increased life spans of mesons or retarded clocks on jets circling the globe, and due to the relativization of simultaneity intrinsic to this theoretical structure. Yet the very structure of the theory demands that such very real physical effects be construed as non-ontological. The scope and depth of this contradiction is explored and, if these (...) time-changes are indeed viewed as ontological effects within STR, an additional problem for the theory is introduced in the context of perception. The origins of this confused situation arise as a result of the fact that STR is an expression of a classical, spatial metaphysic – a framework that equally underpins current discussions of the hard problem. This metaphysic holds an inadequate concept of time and a failure to acknowledge the reality of simultaneous causal flows. These problems are developed against the background of an alternative, namely, the temporal metaphysic of Bergson – a framework that provides a profoundly different base for viewing both relativity and consciousness. (shrink)

Our goal is to investigate the biological correlates of the first-person experience of time or phenomenal time. ‘Time’ differs in various domains, such as (i) physical time (e.g., clock time), (ii) biological time, such as the suprachiasmatic nucleus, and (iii) the perceptual rate of time. One psychophysical-measure of the perceptual rate is the critical flicker frequency (CFF), in which a flashing light is perceived as unchanging. Focusing on the inability to detect change, as in CFF, may give us insight into (...) phenomenal time. CFF varies from 24 Hz for dim light and 60 Hz in bright light and is lower for colored lights. We propose that problem of the phenomenal time can be addressed using two contrasting but complementary approaches (inability to detect changes vs. ability to detect changes): (1) The soliton-catalytic model that entails invariant quantum coherent state for temporal frequencies (TFs) >= CFF, where flickering light is perceived as unchanging, similar to a Bose-Einstein condensate (BEC). (2) Temporal frequency tuned mechanisms model, which starts with ability to detect changes for TFs < CFF and then their sensitivities decreases to zero at CFF. For a subject who has CFF of 60 Hz, the duration of one cycle or time-period of the flickering light is approximately 16.7 ms. Phenomenal time may be quantized into ‘subjective occasions of experience’ (SE), which arise out of the interaction of the individual with situation (environment). Pioneering work examining the complex interaction of neurons suggests the possibility that macroscopic quantum states similar to a BEC may also occur in the brain (Davia, 2006; Freeman & Vitiello, 2006; Georgiev, 2004; Vimal & Davia, 2008) . (shrink)

In this paper epistemological, ontological and sociological questions concerning the statistical significance of sharp hypotheses in scientific research are investigated within the framework provided by Cognitive Constructivism and the FBST (Full Bayesian Significance Test). The constructivist framework is contrasted with the traditional epistemological settings for orthodox Bayesian and frequentist statistics provided by Decision Theory and Falsificationism.