A point charge accelerating under the influence of an external force emits electromagnetic radiation that reduces the increase in its mechanical energy. This causes a reduction in the particle's acceleration. We derive the decrease in acceleration due to radiation reaction for a particle accelerating parallel to its velocity, and show that it has a negligible effect.

It has been shown by Gupta and Padmanabhan that the radiation reaction force of the Abraham–Lorentz–Dirac equation can be obtained by a coordinate transformation from the inertial frame of an accelerating charged particle to that of the laboratory. We show that the problem may be formulated in a flat space of five dimensions, with five corresponding gauge fields in the framework of the classical version of a fully gauge covariant form of the Stueckelberg–Feynman–Schwinger covariant mechanics (the zero (...) mode fields of the 0, 1, 2, 3 components correspond to the Maxwell fields). Without additional constraints, the particles and fields are not confined to their mass shells. We show that in the mass-shell limit, the generalized Lorentz force obtained by means of the retarded Green's functions for the five dimensional field equations provides the classical Abraham–Lorentz–Dirac radiation reaction terms (with renormalized mass and charge). We also obtain general coupled equations for the orbit and the off-shell dynamical mass during the evolution as well as an autonomous non-linear equation of third order for the off-shell mass. The theory does not admit radiation if the particle does not move off-shell. The structure of the equations implies that mass-shell deviation is bounded when the external field is removed. (shrink)

The self force of electrodynamics is derived from a scalar field. The resulting equation of motion is free of all of the problems that plague the Lorentz Abraham Dirac equation. The age-old problem of a particle in a constant field is solved and the solution has intuitive appeal.

It is shown that the well-known disparity in classical electrodynamics between the power losses calculated from the radiation reaction and that from Larmor’s formula, is succinctly understood when a proper distinction is made between quantities expressed in terms of a “real time” and those expressed in terms of a retarded time. It is explicitly shown that an accelerated charge, taken to be a sphere of vanishingly small radius \, experiences at any time a self-force proportional to the (...) acceleration it had at a time \ earlier, while the rate of work done on the charge is obtained by a scalar product of the self-force with the instantaneous value of its velocity. Now if the retarded value of acceleration is expressed in terms of the present values of acceleration, then we get the rate of work done according to the radiation reaction equation, however if we instead express the present value of velocity in terms of its time-retarded value, then we get back the familiar Larmor’s radiation formula. From this simple relation between the two we show that they differ because Larmor’s formula, in contrast with the radiation reaction, is written not in terms of the real-time values of quantities specifying the charge motion but is instead expressed in terms of the time-retarded values. Moreover, it is explicitly shown that the difference in the two formulas for radiative power loss exactly matches the difference in the temporal rate of the change of energy in the self-fields between the retarded and real times. From this it becomes obvious that the ad hoc introduction of an acceleration-dependent energy term, usually referred to in the prevalent literature as Schott-term, in order to make the two formulas comply with each other, is redundant. (shrink)

The appearance of the time derivative of the acceleration in the equation of motion (EOM) of an electric charge is studied. It is shown that when an electric charge is accelerated, a stress force exists in the curved electric field of the accelerated charge, and in the case of a constant linear acceleration, this force is proportional to the acceleration. This stress force acts as a reaction force which is responsible for the creation of the (...) radiation (instead of the “radiation reaction force” that actually does not exist at low velocities). Thus the initial acceleration should be supplied as an initial condition for the solution of the EOM of an electric charge. (shrink)

A new scheme is proposed in order to deduce an equation of motion for a spinless charged point particle leading to an equivalent Landau–Lifshitz equation of motion. Consequently Larmor’s formula must be substituted by a new expression for the large distance radiation rate of energy. A constraint appears on the applicability of the Maxwell electromagnetic tensor. The particular case of a sudden force is analyzed in order to show the physical results predicted by the new model. A geometrical (...) rearrangement of the energy explains the balance. (shrink)

We present an approach to understanding the origin of inertia involving the electromagnetic component of the quantum vacuum and propose this as a step toward an alternative to Mach's principle. Preliminary analysis of the momentum flux of the classical electromagnetic zero-point radiation impinging on accelerated objects as viewed by an inertial observer suggests that the resistance to acceleration attributed to inertia may be at least in part a force of opposition originating in the vacuum. This analysis avoids the (...) ad hoc modeling of particle-field interaction dynamics used previously by Haisch, Rueda, and Puthoff (Phys. Rev. A 49, 678, (1994)) to derive a similar result. This present approach is not dependent upon what happens at the particle point, but on how an external observer assesses the kinematical characteristics of the zero-point radiation impinging on the accelerated object. A relativistic form of the equation of motion results from the present analysis. Its manifestly covariant form yields a simple result that may be interpreted as a contribution to inertial mass. We note that our approach is related by the principle of equivalence to Sakharov's conjecture (Sov. Phys. Dokl. 12, 1040, (1968)) of a connection between Einstein action and the vacuum. The argument presented may thus be construed as a descendant of Sakharov's conjecture by which we attempt to attribute a mass-giving property to the electromagnetic component—and possibly other components—of the vacuum. In this view the physical momentum of an object is related to the radiative momentum flux of the vacuum instantaneously contained in the characteristic proper volume of the object. The interaction process between the accelerated object and the vacuum (akin to absorption or scattering of electromagnetic radiation) appears to generate a physical resistance (reaction force) to acceleration suggestive of what has been historically known as inertia. (shrink)

An alternative approach to analyze the nonrelativistic quantum dynamics of a rigid and extended charged particle taking into account the radiation reaction is discussed with detail. Interpretation of the field operators as annihilation and creation ones, theory of perturbations and renormalization are not used. The analysis is carried out in the Heisenberg picture with the electromagnetic field expanded in a complete orthogonal basis set of functions which allows the electromagnetic field to satisfy arbitrary boundary conditions. The corresponding coefficients (...) are the field operators which satisfy the usual commutation relations. A nonlinear equation of motion for the charged particle is obtained. A careful consideration of the quantum effects allows the derivation of a linear equation of motion which is free of both runaway solutions and preacceleration, even for a point charge. Also, the electromagnetic mass, which is defined as the coefficient of the acceleration operator, vanishes for a point particle. However, this does not mean that the results are free of ambiguities which are exhibited and discussed. (shrink)

Consideration of the velocity-field momentum of an accelerating charged particle leads to an explanation of the Schott force accompanying the radiation reaction.

The complete description of the interaction between an external electromagnetic field and a charged particle causing it to radiate is one of the most fundamental problems in classical electrodynamics. Here we provide a simple coupled model that describes via the Lagrangian of the physical system the full radiation reaction process resulting from the particle–field interactions which simulate the electromagnetic ones. The particle and field evolution equations obtained from the Lagrangian are studied as an initial value problem giving rise (...) to the particle's radiation reaction equation, which includes the complete interaction with the field. Using stability theory we analyze this equation and prove that every solution is global uniform asymptotically stable, evidencing that the particle coupled to the field radiates. The model proves to be interesting, for it clearly illustrates the particle–field interaction process and shows the radiation's origin. (shrink)

We examine the problem of deducing the geodesic motion of test particles from Einstein's vacuum field equations and its extension to include gravitational radiation reaction. In the latter case we obtain an equation of motion for a particle which incorporates radiation reaction of the electrodynamical type, but due to shearing radiation, together with a mass-loss formula of the Bondi-Sachs type.

We analyze the situation of an observer coaccelerated relative to a linearly accelerated charge, in order to find whether he can observe the radiation emitted from the accelerated charge. It is found that the seemingly special situation of the coaccelerated observer relative to any other observer, is deduced from a wrong use of the retarded coordinate system, when such a system is inadmissible. It is also found that the coaccelerated observer has no special position other than any other observer, (...) and hence, he can observe any physical events as any other observer. (shrink)

In order to understand the rise of runaway solutions in the radiation reaction problem a mechanical model is used. An alternative demonstration of Daboul’s theorem, through Hurwitz’s criterion, is given. The origin of runaway solutions in electrodynamics is discussed. They arise when the particle has a negative mechanical mass or when approximations are used in the equation of motion. In the 1-dimensional mechanical model an exact and linear equation of motion for the particle is obtained, the corresponding exact (...) solution is again runaway when the mechanical mass is negative. The exact solution is not runaway when the mechanical mass is positive. However, the use of approximations leads to an equation of motion which has runaway solutions. It is exhibited that the use of approximations in the 3-dimensional mechanical model is completely necessary because the general equation of motion for the particle is non-linear. The analysis of this case proceeds in a very similar way to the one carried out in electrodynamics. This means that the number of dimensions also plays an important role in the analysis. (shrink)

We revisit the nonrelativistic problem of a bound, charged particle subject to the random zero-point radiation field, with the purpose of revealing the mechanism that takes it from the initially classical description to the final quantum-mechanical one. The combined effect of the zpf and the radiation reaction force results, after a characteristic time lapse, in the loss of the initial conditions and the concomitant irreversible transition of the dynamics to a stationary regime controlled by the field. (...) In this regime, the canonical variables x, p become expressed in terms of the dipolar response functions to a set of field modes. A proper ordering of the response coefficients leads to the matrix representation of quantum mechanics, as was proposed in the early days of the theory, and to the basic commutator x^,p^=iħ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left[ {\hat{x}},{\hat{p}}\right] =i\hbar $$\end{document}. Further, the connection with the corresponding Fokker–Planck equation valid in the Markov approximation, allows one to obtain the radiative corrections of qed. These results reaffirm the essentially electrodynamic and stochastic nature of the quantum phenomenon, as proposed by stochastic electrodynamics. (shrink)

We present a stochastic theory for the nonequilibriurn dynamics of charges moving in a quantum scalar field based on the worldline influence functional and the close-time-path (CTP or in-in) coarse-grained effective action method. We summarize (1) the steps leading to a derivation of a modified Abraham-Lorentz-Dirac equation whose solutions describe a causal semiclassical theory free of runaway solutions and without pre-acceleration patholigies, and (2) the transformation to a stochastic effective action, which generates Abraham-Lorentz-Dirac-Langevin equations depicting the fluctuations of a particle’s (...) worldline around its semiclassical trajectory. We point out the misconceptions in trying to directly relate radiation reaction to vacuum fluctuations, and discuss how, in the framework that we have developed, an array of phenomena, from classical radiation and radiation reaction to the Unruh effect, are interrelated to each other as manifestations at the classical, stochastic and quantum levels. Using this method we give a derivation of the Unruh effect for the spacetime worldline coordinates of an accelerating charge. Our stochastic particle-field model, which was inspired by earlier work in cosmological backreaction, can be used as an analog to the black hole backreaction problem describing the stochastic dynamics of a black hole event horizon. (shrink)

We investigate in detail the electromagnetic fields of a uniformly accelerated charge, in order to ascertain whether such a charge does ‘emit’ radiation, especially in view of the Poynting flow computed at large distances and taken as an evidence of radiation emitted by the charge. In this context, certain important aspects of the fields need to be taken into account. First and foremost is the fact that in the case of a uniformly accelerated charge, one cannot ignore the (...) velocity fields. This then leads to other equally vital points. The net field energy turns out to be exactly the same as that of a non-accelerated charge having a uniform velocity equal to the instantaneous velocity of the uniformly accelerated charge. Further, the Poynting vector, seen with respect to the ’present’ location of the uniformly accelerated charge, during the deceleration phase, possesses everywhere a radial component pointing inward toward the charge, becoming nil when the charge becomes momentarily stationary, and during the acceleration phase, points away from the charge position. Last, but not least, when the leading spherical front of the relativistically beamed Poynting flux, advances forward at a large time t to a far-off distance \, the charge too is not lagging far behind. In fact, these relativistically beamed fields, increasingly resemble fields of a charge moving in an inertial frame with a uniform velocity \, with a convective flow of fields in that frame along with the movement of the charge. There is no other Poynting flow in the far-zones that could be termed as radiation emitted by the charge which, in turn, is fully consistent with the absence of radiation reaction and is also fully conversant with the strong principle of equivalence. (shrink)

In the traditional frame of classical electrodynamics, a hydrogen atom would emit electromagnetic waves and thus constantly lose energy, resulting in the fall of the electron on the proton over a finite period of time. The corresponding results were derived under the assumption of the instantaneous interaction between the proton and the electron. In 2004, Raju published a paper where he removed the assumption of the instantaneous interaction and studied the role of a time delay in the classical hydrogen atom. (...) He introduced a model of this effect that can be solved analytically. He calculated the radius rsel of a selected orbit, for which this effect and the radiation reaction force would cancel each other with respect to the tangential acceleration. It turned out that rsel is by an order of magnitude smaller than the Bohr radius. In the present paper we use Raju’s model for the corresponding gravitational situation. In frames of Newton’s gravity, we calculate analytically the radius and the energy Esel of a selected orbit, for which the retardation effect and the radiation reaction force would cancel each other out with respect to the tangential acceleration. Then we compare our outcome with some results of Kaplan’s solution for the two-body gravitational problem based on the Schwarzschild’s field. We show that Esel is very close to the minimum energy of bound states obtained by Kaplan in Einstein’s gravity. We emphasize that the selected orbit from the present paper represents the second only physical situation where the radiation reaction force is zero, but the radiation-caused energy loss is not zero. (shrink)

We consider the simple case of a nonrelativistic charged harmonic oscillator in one dimension, to investigate how to take into account the radiation reaction and vacuum fluctuation forces within the Schrödinger equation. The effects of both zero-point and thermal classical electromagnetic vacuum fields, characteristic of stochastic electrodynamics, are separately considered. Our study confirms that the zero-point electromagnetic fluctuations are dynamically related to the momentum operator p=−i ℏ ∂/∂ x used in the Schrödinger equation.

The connection between stochastic electrodynamics (SED) and the quantum theory of matter is further explored. The main result is that the Fokker-Planck-like equation of SED can be recast into the form of a Schrödinger equation with radiative corrections, when the system is close to a state of equilibrium. The phase-space distribution can be written as Wigner's pseudo-distribution plus corrections due to the nonlinearity of the external force and to radiative effects. The radiative corrections predicted by the theory, namely the (...) Lamb shift and the decay of excited atomic states, coincide with those predicted by QED. Moreover, the theory offers a clear physical interpretation of these phenomena as due to the coupling of the electric dipole of the system with the zero-point radiation field and to radiation reaction, respectively. (shrink)

Conventional rockets are not a suitable technology for interstellar missions. Chemical rockets require a very large weight of propellant, travel very slowly compared to light speed, and require significant energy to maintain operation over periods of years. For example, the 722 kg Voyager spacecraft required 13,600 kg of propellant to launch and would take about 80,000 years to reach the nearest star, Proxima Centauri, about 4.3 light years away. There have been various attempts at developing ideas on which one might (...) base a spacecraft that would permit interstellar travel, such as spacewarps. In this paper we consider another suggestion from science fiction and explore how the quantum vacuum might be utilized in the creation of a novel spacecraft. The spacecraft is based on the dynamic Casimir effect, in which electromagnetic radiation is emitted when an uncharged mirror is properly accelerated in vacuum. The radiative reaction produces a dissipative force on the mirror that tends to resist the acceleration of the mirror. This force can be used to accelerate a spacecraft attached to the mirror. We also show that, in principle, one could obtain the power to operate the accelerated mirror in such a spacecraft using energy extracted from the quantum vacuum using the standard Casimir effect with a parallel plate geometry. Unfortunately the method as currently conceived generates a miniscule thrust, and is no more practical than a spacewarp, yet it does provide an interesting demonstration of our current understanding of the physics of the quantized electromagnetic field in vacuum. (shrink)

The analysis of this article is entirely within classical physics. Any attempt to describe nature within classical physics requires the presence of Lorentz-invariant classical electromagnetic zero-point radiation so as to account for the Casimir forces between parallel conducting plates at low temperatures. Furthermore, conformal symmetry carries solutions of Maxwell’s equations into solutions. In an inertial frame, conformal symmetry leaves zero-point radiation invariant and does not connect it to non-zero-temperature; time-dilating conformal transformations carry the Lorentz-invariant zero-point radiation spectrum (...) into zero-point radiation and carry the thermal radiation spectrum at non-zero temperature into thermal radiation at a different non-zero temperature. However, in a non-inertial frame, a time-dilating conformal transformation carries classical zero-point radiation into thermal radiation at a finite non-zero-temperature. By taking the no-acceleration limit, one can obtain the Planck radiation spectrum for blackbody radiation in an inertial frame from the thermal radiation spectrum in an accelerating frame. Here this connection between zero-point radiation and thermal radiation is illustrated for a scalar radiation field in a Rindler frame undergoing relativistic uniform proper acceleration through flat spacetime in two spacetime dimensions. The analysis indicates that the Planck radiation spectrum for thermal radiation follows from zero-point radiation and the structure of relativistic spacetime in classical physics. (shrink)

BackgroundEach individual’s unique health-related beliefs can greatly impact the patient-clinician relationship. When there is a conflict between the patient’s preferences and recommended medical care, it can create a serious ethical dilemma, especially in an emergency setting, and dramatically alter this important relationship.Case presentationA 56-year-old man, who remained comatose after out-of-hospital cardiac arrest, was rushed to our hospital. The patient was scheduled for emergency coronary angiography when his adolescent daughter reported that she and her father held sincere beliefs against radiation (...) exposure. We were concerned that she did not fully understand the potential consequences if her father did not receive the recommended treatment. A physician provided her with in depth information regarding the risks and benefits of the treatment. While we did not want to disregard her statement, we opted to save the patient’s life due to concerns about the validity of her report.ConclusionsVariations in beliefs regarding medical care force clinicians to incorporate patient beliefs into medical practice. However, an emergency may require a completely different approach. When faced with a patient in a life-threatening condition and unconscious, we should take action to prioritize saving their life, unless we are highly certain about the validity of their advance directives. (shrink)

It is suggested that an understanding of blackbody radiation within classical physics requires the presence of classical electromagnetic zero-point radiation, the restriction to relativistic (Coulomb) scattering systems, and the use of discrete charge. The contrasting scaling properties of nonrelativistic classical mechanics and classical electrodynamics are noted, and it is emphasized that the solutions of classical electrodynamics found in nature involve constants which connect together the scales of length, time, and energy. Indeed, there are analogies between the electrostatic forces (...) for groups of particles of discrete charge and the van der Waals forces in equilibrium thermal radiation. The differing Lorentz- or Galilean-transformation properties of the zero-point radiation spectrum and the Rayleigh-Jeans spectrum are noted in connection with their scaling properties. Also, the thermal effects of acceleration within classical electromagnetism are related to the existence of thermal equilibrium within a gravitational field. The unique scaling and phase-space properties of a discrete charge in the Coulomb potential suggest the possibility of an equilibrium between the zero-point radiation spectrum and matter which is universal (independent of the particle mass), and an equilibrium between a universal thermal radiation spectrum and matter where the matter phase space depends only upon the ratio mc 2/k B T. The observations and qualitative suggestions made here run counter to the ideas of currently accepted quantum physics. (shrink)

We argue that the asymmetry between diverging and converging electromagnetic waves is just one of many asymmetries in observed phenomena that can be explained by a past hypothesis and statistical postulate (together assigning probabilities to different states of matter and field in the early universe). The arrow of electromagnetic radiation is thus absorbed into a broader account of temporal asymmetries in nature. We give an accessible introduction to the problem of explaining the arrow of radiation and compare our (...) preferred strategy for explaining the arrow to three alternatives: (i) modifying the laws of electromagnetism by adding a radiation condition requiring that electromagnetic fields always be attributable to past sources, (ii) removing electromagnetic fields and having particles interact directly with one another through retarded action-at-a-distance, (iii) adopting the Wheeler-Feynman approach and having particles interact directly through half-retarded half-advanced action-at-a-distance. In addition to the asymmetry between diverging and converging waves, we also consider the related asymmetry of radiation reaction. (shrink)

An analysis is carried out involving reversible thermodynamic operations on arbitrarily shaped small cavities in perfectly conducting material. These operations consist of quasistatic deformations and displacements of cavity walls and objects within the cavity. This analysis necessarily involves the consideration of Casimir-like forces. Typically, even for the simplest of geometrical structures, such calculations become quite complex, as they need to take into account changes in singular quantities. Much of this complexity is reduced significantly here by working directly with the change (...) in electromagnetic fields as a result of the deformation and displacement changes. A key result of this work is the derivation that for such cavity structures, classical electromagnetic zero-point radiation is the appropriate spectrum at a temperature of absolute zero to ensure that the reversible deformation operations obey both isothermal and adiabatic conditions. In addition, a generalized Wien displacement law is obtained from the demand that the change in entropy of the radiation in these arbitrarily shaped structures must be a state function of temperature and frequency. (shrink)

This book presents, for the first time in English, a comprehensive anthology of essays on Christian Wolff's psychology written by leading international scholars. Christian Wolff is one of the towering figures in 18th-century Western thought. In the last decades, the publication of Wolff's Gesammelte Werke by Jean École and collaborators has aroused new interest in his ideas, but the meaning, scope, and impact of his psychological program have remained open to close and comprehensive analysis and discussion. That is what this (...) volume aims to do. This is the first volume in English completely devoted to Wolff's efforts to systematize empirical and rational psychology, against the background of his understanding of scientific method in metaphysics. Wolff thereby paved the way to the very idea of a scientific psychology. The book is divided into two parts. The first one covers the theoretical and historical meaning and scope of Wolff's psychology, both in its internal structure and in its relation to other parts of his philosophical system, such as logic, cosmology, aesthetics, or practical philosophy. The second part deals with the reception and impact of Wolff's psychology, starting with early reactions from his disciples and opponents, and moving on to Kant, Hegel, and Wundt. The Force of an Idea: New Essays on Christian Wolff's Psychology shows not only that Wolff's psychological ideas have been misinterpreted, but also that they are historically more significant than traditional wisdom has it. The book, therefore, will be of interest to historians and philosophers of science, historians of philosophy and psychology, as well as to philosophers and psychologists interested in understanding the roots of scientific psychology in 18th and 19th century German philosophy. (shrink)

On 30 June 1994 the Social Democratic Party of Japan (SDPJ, formerly the Japan Socialist Party) joined its historic enemy, the Liberal Democratic Party (LDP), to form a coalition government in a Japanese equivalent of Italy's . Competition between the conservative LDP and the progressive socialists had defined the Japanese party system since 1955. In this paper we analyze voter reactions to this and other confusing events surrounding the end of the LDP's 38-year dominance. We find, first, that the Japanese (...) electorate was able to make sense of these events. The political space reflected in public opinion mapped the political space reflected in the mass media remarkably well. Secondly, our findings support the idea that attitudes toward political parties are endogenous to the political process: strategic moves by political actors alter the political space within which they maneuver. Coalitions of strange bedfellows force voters to revise their perceptions of political space and reevaluate their attitudes toward the actors involved. Strange bedfellows seemed less strange, friendlier after they had been seen in bed together. (shrink)

In many physical systems, coupling forces provide a way of carrying the energy stored in adjacent harmonic oscillators from place to place, in the form of waves. The wave equations governing such phenomena are time-symmetric: they permit the opposite processes, in which energy arrives at a point in the form of incoming concentric waves, to be lost to some external system. But these processes seem rare in nature. What explains this temporal asymmetry, and how is it related to the thermodynamic (...) asymmetry? This paper attempts to clarify these old issues, in the light of recent contributions. After brief introductory remarks (§1), the paper is in three main parts. §2 examines the so-called ‘Sommerfeld Radiation Condition’, arguing that its link to the observed asymmetry is much less direct than commonly supposed. §3 begins with Zeh's proposal to make the Sommerfeld condition an ingredient in an explanation of the observed asymmetry, and makes explicit a useful distinction between two ways in which the thermodynamic asymmetry might connect to the radiation asymmetry. §4 reviews a proposal I have defended in earlier work about the relation of the radiative asymmetry to that of thermodynamics, and defends it against recent objections by Zeh and Frisch. I also distinguish it from a recent proposal due to North. I agree with North that the observed asymmetry of radiation stems from the low entropy history, but argue that she mis-characterises the asymmetry, and hence misses a crucial element in a proper account of the role of the low entropy past. (shrink)

This paper reviews the origin of inertia according to Mach's principle and Weber's law of gravitation. The resulting theory is based on simultaneous nonlocal gravitational interactions between particles in the solar system and others in the remote universe beyond the Milky Way galaxy. It explains the precession of the perihelion of Mercury. A most important implication of the Mach-Weber theory of the force of inertia is the necessity for a large amount of uniformly distributed matter in the galactic universe. (...) This matter could be the source of the cosmic background radiation. Nonlocal inertia forces are compatible with a static universe and also with an expanding universe but the latter would demand slow changes in the mass of particles and the gravitational constant. (shrink)

The equivalence principle as well as the spin-two character of the weak gravitational field lead to difficulties in the measurability analysis of this field which are not encountered in Bohr and Rosenfeld's corresponding inquiry into the electromagnetic field. To meet these difficulties, atomic elastic structures are proposed as gravitational field detectors whose parameters (masses, total volumes, lattice and elastic constants) are adjustable. The limitations imposed by the uncertainty principle and by the radiation reaction of the detectors on the (...) determination of the amplitude, frequency, and direction of the field are then exhibited. Finally, the relevance of the present work to the investigation of DeWitt and to Einstein's full theory of gravitation is briefly considered. (shrink)

In this article we analyze the method of forcing from a more philosophical perspective. After a brief presentation of this technique we outline some of its philosophical imports in connection with realism. We shall discuss some philosophical reactions to the invention of forcing, concentrating on Mostowski’s proposal of sharpening the notion of generic set. Then we will provide an overview of the notions of multiverse and the related philosophical debate on the foundations of set theory. In conclusion, we connect this (...) modern debate and Mostowski’s proposal, suggesting a way to analyze the notion of genericity within the framework of a multiverse structure. (shrink)

Environmental heterogeneity is invoked as a key explanatory factor in the adaptive evolution of a surprisingly wide range of phenomena. This article aims to analyze this explanatory scheme of categorizing traits or properties as adaptations to environmental heterogeneity. First it is suggested that this scheme can be understood as a reaction to how heterogeneity adaptations were discounted or ignored in the modern synthesis. Then a positive account is proposed, distinguishing between two broad categories of adaptation to environmental heterogeneity: properties (...) selected for by well-defined patterns of environmental heterogeneity, and properties that help organisms exploit novel patterns of environmental heterogeneity. (shrink)

In the sacrificial moral dilemma task, participants have to morally judge an action that saves several lives at the cost of killing one person. According to the dual process corrective model of moral judgment suggested by Greene and collaborators (2001; 2004; 2008), cognitive control is necessary to override the intuitive, deontological force of the norm against killing and endorse the utilitarian perspective. However, a conflict model has been proposed more recently to account for part of the evidence in favor (...) of dual process models in moral and social decision making. In this model, conflict, moral responses and reaction times arise from the interplay between individually variable motivational factors and objective parameters intrinsic to the choices offered. To further explore this model in the moral dilemma task, we confronted three different samples with a set of dilemmas representing an objective gradient of utilitarian pull, and collected data on moral judgment and on conflict in a 4-point scale. Collapsing all cases along the gradient, participants in each sample felt less conflicted on average when they gave extreme responses (1 or 4 in the UR scale). They felt less conflicted on average when responding to either the low- or the high-pull cases. The correlation between utilitarian responses and conflict was positive in the low-pull and negative in the high-pull cases. This pattern of data suggests that moral responses to sacrificial dilemmas are driven by decision conflict, which in turn depends on the interplay between an objective gradient of utilitarian pull and the moral motivations which regulate individual responsiveness to this gradient. (shrink)

Following the depiction theory by Clark and Fischer we would expect people interacting with robots to experience fictional emotions akin to those toward films or novels. However, some people's emotional reactions toward robots display the motivational force typical to non-fictional emotions. We discuss this incongruity and offer two suggestions on how to explain it while maintaining the depiction theory.

In this paper, I discuss from a philosophical viewpoint the so-called radiation problem that resulted from the Fukushima Daiichi Nuclear Power Station accident after the Great East Japan Earthquake in 2011. The starting point lies in the conceptual distinction between “damage due to radiation” and “damage caused by avoiding radiation.” We can recognize the direct “damage due to radiation” in Fukushima as not serious based on the empirical data so that I focus upon the problem of (...) the “damage caused by avoiding radiation,” particularly the damage due to evacuation actions. Actually, evacuation actions caused more refugees to die of suicide and diseases than supposed. Obviously, there is a practical problem on whether the forceful and emergent evacuationwas needed. In addition, I will point out that some people psychologically had negative feelings about the radiation problem altogether, for example, absurdity, discomfort, anxiety, or distrust, where some of them tend to twistedly solve those by giving moral censure to people and the product in affected areas. This brought about serious harm to people in Fukushima. I will interpret some people’s careless adoption of precautionary principle and their misunderstanding of the legal standard in radiation protection as being latent in this tragedy. (shrink)

Towards the second decade of the nineteenth century Seebeck discovered that when two different conductors are joined together at both ends with the two junctions kept at different temperatures, an electromotive force arises. Seebeck's discovery, thanks to Melloni, converted the thermopile into the best measuring apparatus for the study of radiation. In this paper I discuss some technical properties of the thermopile used by Melloni in his early studies on radiant heat polarization; quantify in modern terms the behaviour (...) of the thermopile; and solve an enigma concerning its sensitivity. (shrink)

Across the globe, radical conservative political forces and ideas are influencing and even transforming the landscape of international politics. Yet IR is remarkably ill-equipped to understand and engage these new challenges. Unlike political theory or domestic political analyses, conservatism has no distinctive place in the fields’ defining alternatives of realism, liberalism, Marxism, and constructivism. This paper seeks to provide a point of entry for such engagement by bringing together what may seem the most unlikely of partners: critical theory and the (...) New Right. Important parts of today’s New Right represent self-conscious appropriations of Critical themes and thinkers—turning them to self-declared “reactionary” ends. Developing outside the confines of the academy, these forms of thought have woven insights from across Critical theory into new and mobilizing forms of conservative ideology, seeking to link that ideology to social forces that play increasingly active roles in global politics. Our intention here is not to somehow blame Critical perspectives for the ideas of the New Right, either directly or by association. Rather, we seek to show how an engagement with Critical theory helps us understand the New Right, while also demonstrating some of the direct challenges the New Right poses for critical perspectives. (shrink)

We consider a model of the state evolution of relativistic vector bosons, which includes both the dynamical equations for the particle four-velocity and the equations for the polarization four-vector evolution in the field of a nonlinear plane gravitational wave. In addition to the gravitational minimal coupling, tidal forces linear in curvature tensor are suggested to drive the particle state evolution. The exact solutions of the evolutionary equations are obtained. Birefringence and tidal deviations from the geodesic motion are discussed.

In the past, a few researchers have presented arguments indicating that a statistical equilibrium state of classical charged particles necessarily demands the existence of a temperature-independent, incident classical electromagnetic random radiation. Indeed, when classical electromagnetic zero-point radiation is included in the analysis of problems with macroscopic boundaries, or in the analysis of charged particles in linear force fields, then good agreement with nature is obtained. In general, however, this agreement has not been found to hold for charged (...) particles bound in nonlinear force fields. The point is raised here that this disagreement arising for nonlinear force fields may be a premature conclusion on this classical theory for describing atomic systems, because past calculations have not directed strict attention to electromagnetic interactions between charges. This point is illustrated here by examining the classical hydrogen atom and showing that this problem has still not been adequately solved. (shrink)

We make a brief review of the Kramers escape rate theory for the probabilistic motion of a particle in a potential well U(x), and under the influence of classical fluctuation forces. The Kramers theory is extended in order to take into account the action of the thermal and zero-point random electromagnetic fields on a charged particle. The result is physically relevant because we get a non-null escape rate over the potential barrier at low temperatures (T → 0). It is found (...) that, even if the mean energy is much smaller than the barrier height, the classical particle can escape from the potential well due to the action of the zero-point fluctuating fields. These stochastic effects can be used to give a classical interpretation to some quantum tunneling phenomena. Relevant experimental data are used to illustrate the theoretical results. (shrink)

A new scheme is proposed in order to deduce an equation of motion for a spinless charged point particle leading to an equivalent Landau–Lifshitz equation of motion. Consequently Larmor’s formula must be substituted by a new expression for the large distance radiation rate of energy. A constraint appears on the applicability of the Maxwell electromagnetic tensor. The particular case of a sudden force is analyzed in order to show the physical results predicted by the new model. A geometrical (...) rearrangement of the energy explains the balance. (shrink)

The reaction of Italian physicists to the innovations of the ‘new physics’ has been studied by analysing their scientific production and their textbooks. Their stand appears to have been the result of several components: absence or weakness of lines of research in the last three decades of the nineteenth century ; firm attachment to the conceptual and philosophical foundations of classical mechanics; and hostility to the quantization of energy. The consequence has been a widening of the gap between the (...) research done in Italy and the main lines of development of the discipline. (shrink)

Moral ideals should not be seen as simple and purely personal, but as complex values with a social dimension that transcend attempts to formulate or realize them. Orientation towards ideals needs a realistic component: people should identify with the quest for an ideal, not with the ideal itself, and consider the possibility of negative consequences of their pursuit. Such realism about ideals includes acknowledging that ideals are not the only, nor the most important, motivating force of morality.

By the start of the Victorian period the school of British economists acknowledging Adam Smith as its master was in the ascendancy. 'Political Economy', a catch-all title which ignored the diversity of viewpoints to be found amongst the discipline's leading proponents, became associated in the popular mind with moral and political forces held to be uniquely conducive to the progress of an increasingly industrialised and competitive society. 'Political Economy' served in turn as the focus for critics of equally diverse moral (...) and political persuasions, who sought to challenge the materialism of contemporary society and offer their own assessments of the profound social changes of the time. In the introductory essay to the collection of readings from such 'critics of capitalism', the editors review the principles of the early economists, the way in which these principles were appropriated and applied by their Victorian successors and the contrasting modes which critics of popular economic ideas assumed. Subsequent extracts from the writings of the Owenite Socialist John Bray, Carlyle, Marx and Engels, J. S. Mill, Ruskin, Arnold, T. H. Green, William Morris and G. B. Shaw, demonstrate both the breadth of the possible grounds for ideological opposition to the prevailing philosophy and the shifting nature of the debate as 'Political Economy' itself was revealed as incapable of explaining or responding to the changing conditions of the 1870s. Headnotes to the extracts describe the genesis of individual debate and discuss distinctive stylistic features. Annotation in the form of footnotes and endnotes has been designed to gloss obscure allusions and arguments. In making more accessible the socio-economic writings of those authors now better known for their imaginative work, this volume will enable readers to reach a more profound appreciation of the central role such work played in developing the moral vision embodied in their more lastingly popular books and essays. (shrink)

Moral ideals should not be seen as simple and purely personal, but as complex values with a social dimension that transcend attempts to formulate or realize them. Orientation towards ideals needs a realistic component: people should identify with the quest for an ideal, not with the ideal itself, and consider the possibility of negative consequences of their pursuit. Such realism about ideals includes acknowledging that ideals are not the only, nor the most important, motivating force of morality.

Professor Zenkovsky's work is a history in the grand manner --and a grand history it is. We are much indebted to Dr. George Kline for his lucid, readable translation. Our historian takes the basic theme of Russian thought to have been the relations of Christianity and secularism. This does not mean that there has been a dearth of studies in logic, philosophy of science, and so on; or that Zenkovsky neglects these or treats them unfairly or unintelligently. But his belief (...) is that "the genuinely vital creative problems of philosophic reflection derive from the Christian gospel and hence cannot be resolved apart from it." In the West, however, it has, he thinks, been difficult to see this because freedom of investigation has there become identified with opposition to the Church, while in Russia it has been possible to defend such freedom "from the religious point of view, taking the ecclesiastical tradition as point of departure, and giving oneself up fully to the 'free spontaneous force of theological investigation,' in Karsavin's familiar expression." The Russian view of the Church, as set forth by Khomyakov and Kireyevski, a hundred years ago, is not that of an "authority" wielded by officials or even councils, but of a community of members forming a spiritual organism in which they reach a level of life involving integral experience of the nature of reality. Ecclesiastical coercion, as in the West, is viewed as a heresy. Faith calls us to a life of freedom, rather than of "obedience." Zenkovsky regards as "romantic" the notion of a generally diffused spiritual insight which would make all important truths perfectly evident, but he seems to agree with the rejection of coercion. (shrink)