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- Adolf Grunbaum (1976). Is Preacceleration of Particles in Dirac's Electrodynamics a Case of Backward Causation? The Myth of Retrocausation in Classical Electrodynamics. Philosophy of Science 43 (2):165-201.Is it a "conceptual truth" or only a logically contingent fact that, in any given kind of case, an event x which asymmetrically causes ("produces") an event y likewise temporally precedes y or at least does not temporally succeed y? A bona fide physical example in which the cause retroproduces the effect would show that backward causation is no less conceptually possible than forward causation. And it has been claimed ([9], p. 151; [4], p. 41) that in Dirac's classical electrodynamics (relativistic and non-relativistic), the preacceleration of charged particles before any forces are applied to them furnishes a genuine case of retrocausation by later forces. An exposition of the pertinent physics furnishes the basis for arguing the following: Whereas the non-zero acceleration of a neutral NEWTONIAN mass particle is, of course, causally connected as such to the simultaneously applied non-zero force, the non-zero acceleration of a DIRACIAN charged particle is not causally connected at all as such to the applied forces. A fortiori, in Dirac's electrodynamics, the applied forces do not qualify asymmetrically as the causes of a non-zero acceleration as such; nor does a non-zero acceleration as such qualify as an effect produced by forces. This is shown by means of two considerations as follows: (1) In Dirac's theory, no functional dependence of the value of a non-zero acceleration on the weighted time-average of the forces is vouchsafed as a matter of physical LAW alone without any value of a constant of integration, just as no Newtonian law(s) alone can guarantee a functional dependence of the non-zero value of the velocity of a Newtonian mass particle on the applied forces. Instead, both functional dependencies alike are vouchsafed only with the crucial aid of some de facto boundary condition pertaining to either the past or to the furute, so that (2) Non-zero preaccelerations of Diracian charged particles can no more be causally attributed as such to the retrocausal action of later forces than non-zero "prevelocities" of Newtonian mass particles can be held to be caused as such by later applied forces. The retrocausal interpretation of Dirac's preaccelerations is just as invalid as the retrocausal interpretation of Newtonian prevelocities.Reading list | Discuss | Edit | Categorize |My bibliography
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Sometimes also called retro causation. A common feature of our world seems to be that in all cases of causation, the cause and the effect are placed in time so that the cause precedes its effect temporally. Our normal understanding of causation assumes this feature to such a degree that we intuitively have great difficulty imagining things differently. The notion of backward causation, however, stands for the idea that the temporal order of cause and effect is a mere contingent feature and that there may be cases where the cause is causally prior to its effect but where the temporal order of the cause and effect is reversed with respect to normal causation, i.e. there may be cases where the effect temporally, but not causally, precedes its cause.
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| | Scholar | At my library | More options ... In this article it is presented the idea that quantum electrodynamics has to be seen as a theoretical upgrade of classical electrodynamics and the theory of relativity, that permits an extension of classical theory in the description of phenomena, that while being clearly related to the conceptual framework of the classical theory – the description of matter, radiation, and their interaction – cannot be properly addressed from the classical theory. In this way quantum electrodynamics would not be a fundamental theory, and principally, we could not consider classical electrodynamics as contained in the quantum theory and being recovered from it by some sort of limiting procedure.
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| | Other links: jstor.org | Scholar | At my library | More options ... In a recent issue of this journal, M. Frisch claims to have proven that classical electrodynamics is an inconsistent physical theory. We argue that he has applied classical electrodynamics inconsistently. Frisch also claims that all other classical theories of electromagnetic phenomena, when consistent and in some sense an approximation of classical electrodynamics, are haunted by “serious conceptual problems” that defy resolution. We argue that this claim is based on a partisan if not misleading presentation of theoretical research in classical electrodynamics.
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| | Other links: journals.uchicago.edu dx.doi.org | Scholar | At my library | More options ... in Dirac's classical theory of the electron—is causally non-local. I distinguish two distinct causal locality principles and argue, using Dirac's theory as my main case study, that neither can be reduced to a non-causal principle of local determinism.
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| | Other links: bjps.oupjournals.org jstor.org dx.doi.org | Scholar | At my library | More options ... This paper defends the view that Newtonian forces are real, symmetrical and non-causal rela- tions. First, I argue that Newtonian forces are real; second, that they are relations; third, that they are symmetrical relations; fourth, that they are not species of causation. The overall picture is anti-Humean to the extent that it defends the existence of forces as external relations irreducible to spatio-temporal ones, but is still compatible with Humean approaches to causation (and others) since it denies that forces are a species of causation.
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| | Scholar | At my library | More options ... Newtonian forces are pushes and pulls, possessing magnitude and direction, that are exerted (in the first instance) by objects, and which cause (in particular) motions. I defend Newtonian forces against the four best reasons for denying or doubting their existence. A running theme in my defense of forces will be the suggestion that Newtonian Mechanics is a special science, and as such has certain prima facie ontological rights and privileges, that may be maintained against various challenges.
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| | Other links: bjps.oxfordjournals.org jstor.org dx.doi.org | Scholar | At my library | More options ... A detailed analysis is made of Grunbaum's claim that the Abraham-Lorentz (AL) and Dirac-Lorentz (DL) equations have no bearing on causality. It is pointed out that (a) both equations are derived from F = ma, and thus should obey the same causality conditions as Newton's law, (b) independently of what boundary conditions are imposed, non-causal behavior is always along the same straight line as the force, (c) the distinction in status between laws and boundary conditions which Grunbaum imposes is one which is not always useful, especially since what is a law in one formulation of the theory can become a boundary condition in another, and thus it is argued that a complete theory must be such that laws and boundary conditions form a coherent whole, (d) the asymptotic boundary conditions that are applied are in agreement with experiment, (e) the AL equation is such that if the "effect," the acceleration as function of time, is known, then the "cause," the force, can be determined. In addition, it is noted that in the DL equation the acceleration at times later than t influences the acceleration at t. Finally, it is pointed out that electrodynamics is indeed a causal field theory, and that retrocausality is due to the transition from a field description to a particle description.
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| | Other links: jstor.org journals.uchicago.edu dx.doi.org | Scholar | At my library | More options ... Dirac's classical electrodynamics countenances "preaccelerations" of charged particles at a time t as mathematical functions of external forces applied after the time t. These preaccelerations have been interpreted as evidence for physical retrocausation upon assuming that, in electrodynamics no less than in Newton's second law, external forces sustain an asymmetric causal relation to accelerations. And this retrocausal interpretation has just been defended against the critiques in (Grunbaum 1976), (Grunbaum and Janis, 1977 and 1978) by appeal to the formal assimilation of the electrodynamic laws of motion to Newton's second law. It is argued below that this latest defense of the retrocausal interpretation is even more ill-founded than the prior ones in the literature.
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| | Other links: jstor.org journals.uchicago.edu dx.doi.org | Scholar | At my library | More options ... Discussion of Adolf Grunbaum, Is preacceleration of particles in dirac's electrodynamics a case of backward causation? The myth of retrocausation in classical electrodynamics
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