Henri Poincaré versus Albert Einstein – SR Priority Question
Wolfgang G. Gasser
Shubee:
Einstein always denied to have known Poincaré's publications. It's hard to believe, as his friends Maurice Solovine and Carl Seelig report Einstein had read Poincaré's book La Science et l'hypothèse (no absolute time, no absolute space, no ether ... ) around 1902-1904.
Your presentation of the facts is actually not far away from dishonesty. Einstein never denied to have read La Science et l'hypothèse. Do you have read this book yourself? Does it suggest special relativity? And are you sure that no one before Poincaré ever had the idea that the best way to synchronize distant clocks is by means of light signals from the center?
The case Einstein-Poincaré is quite similar to the case Einstein-Hilbert. There is confusion between
1) Sur la Dynamique de l'Électron, Comptes rendus hebdomadaires des séances de L'Académie des sciences, Volume 140, (5 June 1905), pp. 1504-1508
2) Sur la Dynamique de l'Électron, Rendiconti del Circolo matimatico di Palermo, Volume 21, (1906, submitted July 23rd, 1905)
3) La dynamique de l'électron, Revue générale des sciences pures et appliquées 19:386-402 (1908)
and maybe even:
4) La dynamique de l'électron par Henri Poincaré (Lectures given by Henri Poincaré in July 1912 at the Ecole Supérieure des Postes et des Télégraphes. Mars 1913, A. Dumas Editeur, Paris. Published and edited posthusmously by Pomey.)
Even if Einstein had known 1), it would not have helped him a lot (see appendix below).
A Lorentzian ether as advocated by Poincaré is inconsistent with a consistent generalization of the so-called Galilean relativity principle to the whole of physics. Such a relativity principle had been consistently advocated by e.g. Ockham (1290-1348), Nicolaus Cusanus (1401-1464) and later also by Immanuel Kant (1724-1804). So "Lorentzian relativity" is at best a misnomer and at worst a contradiction.
The classical relativity principle presupposes the inertia principle (often attributed to Galilei but) advocated at the latest by Ibn Sina (Avicenna) a millennium ago. Relevant quotations from Avicenna can be found in this posting.
According to the classical relativity principle as conceived by e.g. Ockham, Cusanus and Kant, all inertial movements are equivalent. According to the theory of Lorentz and Poincaré however, that is obviously not the case. Still in June 1905 Poicaré wrote (translated by me):
Lorentz was also led to assume that the moving electron takes the form of a compressed ellipsoid; ...
... and at the same time [one gets] a possible explanation of the electron contraction, in assuming that the electron, deformable and compressible, is subject to a kind of exterior constant pressure whose effect [travail] is proportional to the variations in volume. ...
The original:
"Lorentz est amené également à supposer que l'électron en mouvement prend la forme d'un ellipsoide aplati; ...
Mais avec l'hypothèse de Lorentz, l'accord entre les formules ne se fait pas tout seul; on l'obtient, et en même temps une explication possible de la contraction de l'électron, en supposant que l'électron, déformable et compressible, est soumis à une sorte de pression constante extérieure dont le travail est proportionnel aux variations du volume." Poincaré, "Sur la dynamique de l'électron.", Comptes rendues 140
So the reproach that Einstein plagiarized somehow a "relativity principle" from Poincaré does not even make sense. (The question however, whether Poincaré profited from Einstein's relativity paper without attribution when publishing his own "relativity theory" in 1906 could still be open.)
And this question is still open:
"D'un autre côté, même si Poincaré n'était pas homme à se mettre sur le devant de la scène, on se demande encore pourquoi la communication à l'Académie des sciences de Paris du 5 juin 1905, «Sur la dynamique de l'électron», reçue en juillet 1905, n'a finalement été publiée qu'en janvier 1906 dans le Circolo matematico di Palermo, revue scientifique de second ordre alors que sa renommée lui autorisait plus de visibilité?" (Source)
Shubee:
At the end of his life, Einstein wrote in 1955 in a letter to Carl Seelig:
"There is no doubt, if we look back to the development of the Relativity theory, special Relativity was about to be discovered in 1905. Lorentz already noticed that the transformations (named Lorentz transformations) were essential in the Maxwell theory and Poincaré had gone even further.
At that time I only knew Lorentz work of 1895, but I knew neither Lorentz nor Poincaré further work.
This why I can say that my work of 1905 was independent" (ref 8, page 11).
Think about it, Einstein had a regular work and a family. It was impossible for him to study all the papers and books that were published in those days. And how could he have known that the best candidates for plagiarism would be just Poincaré and Lorentz?
___
Translated extracts from Poincaré, June 1905:
"... It seems that this impossibility of determining the absolute motion is a general law of nature.
An explanation has been proposed by Lorentz who introduced the hypothesis of a contraction of all objects in direction of the motion; ... Lorentz tried to complete and modify his hypothesis in order to make it consistent with the postulate of the full impossibility of determining the absolute motion. ...
The essential point, established by Lorentz, is that the equations of the electromagnetic field do not change under a certain transformation (which I'll call Lorentz transformation) and ...
... These transformations, ..., must form a group; however, for this to be so, it is necessary that l = 1; hence we are led to assume that l = 1 and this is a consequence which Lorentz had found by a different way. ...
Lorentz was also led to assume that the moving electron takes the form of a compressed ellipsoid; ...
... and at the same time [one gets] a possible explanation of the electron contraction, in assuming that the electron, deformable and compressible, is subject to a kind of exterior constant pressure whose effect [travail] is proportional to the variations in volume. ...
But that is not enough: Lorentz considered it necessary to complete his hypothesis by assuming that all forces, of any origin, are affected in the same way by a translation as the electromagnetic forces and that therefore the effect of a Lorentz transformation is once again defined by the equations (4)."
The originals of the translated extracts:
"... Il semble que cette impossibilité de démontrer le mouvement absolu soit une loi générale de la nature.
Une explication a été proposée par Lorentz, qui a introduit l'hypothèse d'une contraction de tous les corps dans le sens du mouvement terrestre; ... Lorentz a cherché à compléter et à modifier son hypothèse de facon à la mettre en concordance avec le postulat de l'impossibilité complète de la détermination du mouvement absolu. ...
Le point essentiel, établi par Lorentz, c'est que les équations du champ électromagnétique ne sont pas altérées par une certaine transformation (que j'appellerai du nom de Lorentz) et ...
... L'ensemble de toutes ces transformations, ... , doit former groupe; mais, pour qu'il en soit ainsi, il faut que l = 1; on est donc conduit à supposer l = 1 et c'est là une conséquence que Lorentz avait obtenue par une autre voie. ...
Lorentz est amené également à supposer que l'électron en mouvement prends la forme d'un ellipsoide aplati; ...
Mais avec l'hypothèse de Lorentz, l'accord entre les formules ne se fait pas tout seul; on l'obtient, et en même temps une explication possible de la contraction de l'électron, en supposant que l'électron, déformable et compressible, est soumis à une sorte de pression constante extérieure dont le travail est proportionnel aux variations du volume.
Mais ce n'est pas tout: Lorentz, dans l'Ouvrage cité, a jugé nécessaire de compléter son hypothèse en supposant que toutes les forces, quelle qu'en soit l'origine, soient affectées, par une translation, de la même manière que les forces électromagnétiques, et que, par conséquent, l'effet produit sur leurs composantes par la transformation de Lorentz est encore défini par les équations (4)."
Wolfgang G.:
Einstein never denied to have read La Science et l'hypothèse.
Juan R.:
However, the point is not whether Einstein read Poincaré during his life. The point is whether Einstein read Poincaré before/during 1905.
Once again Einstein:
Concerning myself, I knew only Lorentz' important work of 1895 La théorie électromagnétique de Maxwell and Versuch einer Theorie der elektrischen und optischen Erscheinungen in bewegten Körpern, but not Lorentz later work, nor the consecutive work of Poincaré. In this sense my work of 1905 was independent.
If one considers La Science et l'hypothèse as "consecutive work of Poincaré" in the relativity domain, then Einstein actually seems to be a liar.
In a similar case, some have accused Einstein of having lied about the Michelson-Morley experiment (see).
I haven't seen until now one single example indicating that Einstein wasn't honest when he replied to questions concerning "prior knowledge". Only if one interprets his answers in a tendentious way, superficial inconsistencies can be constructed.
Priority questions are rather irrelevant. However, the question of scientific (dis)honesty is crucial.
Juan R.:
Contrary to a popular misunderstanding Einstein's work was not revolutionary, but a continuation of previous research by other authors.
But at least from a philosophical point of view, there is a huge difference between Lorentz-Poincaré, assuming that matter in motion with respect to the ether is "subject to a kind of exterior constant pressure", and Einstein's space-time concept.
Juan R.:
Also the confusion arose because Einstein did not cite the work of others.
Should he have cited all the books and articles which over years had helped him to write this article? A correct listing of all references could have been more work than the article itself.
In any case, it is more honest to publish something without references than with an incomplete listing of references.
Juan R.:
The Nobel laureate for physics Max Born excellently resumed the impression that one receives when reading Einstein's paper by the first time:
[Einstein's] paper Zur Elektrodynamik bewegter Körper in Annalen der Physik [...] contains not a single reference to previous literature. It gives you the impression of quite a new venture.
I think this comment is malicious for the following reasons.
Einstein was a regular contributor to the 'Annalen der Physik', having published apart from articles also reviews of works of others. And in the article, he deals with the equations of Maxwell/Hertz and with Lorentz' electrodynamics.
So the insinuation that by omitting references Einstein tried to give the impression that he had written this article independently from all others does not make a lot of sense.
And the Poincaré synchronization procedure is such a basic thing that it simply is absurd to assume that Einstein could not have created relativity without having learned this point from Poincaré.
Juan R.:
Since physicists and historians found striking similarities between Einstein's 1905 paper and previous works by other authors.
Could you cite these "striking similarities"? Where can we find the claim that inertial frames are generally linked by the Lorentz transformation? Where can we find the velocity addition formulas?
Also the 'impossibility to detect the absolute motion' (later called relativity principle by Poincaré) was rather an empirical fact suggested by the many unsuccessful attempts to detect motion with respect to the ether than an insight which must be attributed specially to Poincaré.
Einstein's relativity principle is rather a further stage of the same principle as advocated e.g. by Immanual Kant ('Neuer Lehrbegriff der Bewegung und Ruhe', 1758) than an 'impossibility to detect the absolute motion'.
The criticism of the lack of references often boils down to this: In 1905 Einstein should have given credit to Poincaré's work of 1905, published however only in 1906.
Wolfgang G.:
The criticism of the lack of references often boils down to this: In 1905 Einstein should have given credit to Poincaré's work of 1905, published however only in 1906.
Juan R.:
Einstein could not have known Poincaré's paper of July 1905 when writing his own paper, but the June 1905 Note to the Academy of Poincaré arrived in Bern, in time, by June 12 or 13, and it was a part of Einstein's job to read it.
Are you serious? Do you suggest that it was Einstein's job at the patent office to read les comptes rendus de l'Académie des sciences de Paris? And as far as I know, Einstein at least in the past had had some problems with the French language. Einstein's relativity paper was received on 1905-06-30 by the Annalen der Physik. Thus it must have been finished at least some days earlier. So there remain only around ten days or two weeks from the theoretical possibility of having read the article of Poincaré to the completion of the relativity paper.
Einstein's thirty-page article is not a conglomerate of ad-hoc-hypotheses but a rather consistent work based on fundamental principles, where most things are linked with each other. Unlike in constructive theories, it is not possible to introduce a new fundamental principle in an already more or less completed theory of principles (Prinzipientheorie). Do you suggest that Einstein wrote the whole article within a maximum of two weeks, or that he substantially reworked the article in those days?
I've found a possible source of your claim:
"Einstein n'a évidemment pas pu utiliser le travail de Poincaré de juillet 1905 pour écrire son propre texte, mais la Note à l'Académie du 5 juin 1905 est arrivée à Berne, à temps, le 12 ou le 13 juin, et la lire faisait partie de son travail ordinaire. On peut d'ailleurs remarquer qu'Einstein résumait régulièrement pour les Annalen der Physik les travaux de physique les plus intéressants, y compris ceux parus dans les comptes rendus de l'Académie des sciences de Paris (voir par exemple la référence 18, avec entre autres l'analyse du travail de M. Ponsot, C.R. 140, S pages 1176-1179, 1905)." http://annales.org/archives/x/poincare7.html
"Référence 18" is a Review of Auguste Ponsot, Heat in the Displacement of the Equilibrium of a Capillary System, Comptes rendues, 1905-05-01. Einstein's review was published in the second half of September.
I could find only one further review of a note of Comptes rendus from 1905 by Einstein: Review of Paul Langevin, On a Fundamental Formula of the Kinetic Theorie, 1905-01-02. This review was published in the second half of June. (See: Comptes rendus, 140, pages 35-38 and 1176-1179)
Both notes are in French, and both notes deal with problems (heat, capillarity, kinetic theory) which also are central in articles Einstein had published earlier. So the hypothesis that others called Einstein's attention especially to these notes could be more reasonable than that Einstein regularly read the Comptes rendus.
Poincaré's note from June 1905 does not contain the word 'relativity'. It would be interesting to analyze the differences between the short and long version of Sur la dynamique de l'électron. In the note Poincaré only wrote: It seems that this impossibility to detect the absolute motion is a general law of Nature.
In the paper published in 1906 he added: We are naturally led to this law, which we will call the postulate of relativity, and to accept it without exception.
("Il semble que cette impossibilité de mettre en évidence expérimentalement le mouvement absolu de la Terre soit une loi générale de la Nature; nous sommes naturellement porté à admettre cette loi que nous appellerons le Postulat de Relativité et à l'admettre sans restriction.")
Very interesting is this (from the 1906 paper):
"Dans cette théorie [de Lorentz], deux longueurs égales, ce sont, par définition, deux longueurs que la lumière met le même temps à parcourir.
Peut-être suffirait-il de renoncer à cette définition, pour que la théorie de Lorentz fût aussi complètement bouleversée que l'a été le système de Ptolémée par l'intervention de Copernic."
That "equal lengths are by definition lengths which light passes in identical times" is probably more characteristic of Einstein's than of Lorentz' theory. Anyway, Poincaré compares a theory based on such a length definition with the system of Ptolemy which later was completely overthrown by Copernicus. And such a revolution, he suggests, might be done by simply rejecting this length definition. (This rejection would obviously also entail a rejection of relativity as conceived by Einstein).
This elegantly shows that Poincaré still left the doors open to other possible developments in physics. Yet Einstein, from the beginning advocated only one single line of reasoning.
In La science and et l'hypothèse there is a chapter on the relativity principle ('Le mouvement relatif et le movement absolu'). It deals however only with the classical relativity principle. In the last chapter 'La fin de la matière' Poincaré mentions the length-contraction hypothesis of Fitzgerald and the assumption of Lorentz that even better experiments will not be able to detect the absolute motion of the earth. "Relativity" is not mentioned, however.
Another quote from http://annales.org/archives/x/poincare7.html:
Le congrès scientifique mondial de Saint-louis (Missouri, septembre 1904, publié en novembre 1904):
Henri Poincaré est invité à présenter une conférence générale sur "L'état actuel et l'avenir de la Physique mathématique". Il ajoute audacieusement le "principe de relativité" au cinq principes classiques de la Physique:
"Le principe de relativité, d'après lequel les lois des phénomènes physiques doivent être les mêmes pour un observateur fixe et pour un observateur entraîné dans un mouvement de translation uniforme, de sorte que nous n'avons et ne pouvons avoir aucun moyen de discerner si nous sommes, oui ou non, emportés dans un pareil mouvement.".
This principle of relativity (i.e. the equivalence of all inertial movements), which Poincaré in 1904 "audaciously added to the five classical principles of physics", had already been considered by many as a fundamental principle of physics over hundreds of years!
In any case, the behavior of Poincaré towards Einstein is quite similar to the behavior of Galilei who fought Kepler in a subtle and efficient way, so that still today many people believe that it was Galilei who created the modern astronomy/physics and that Kepler still believed in Aristotelian physics. (On Kepler see.)
So one might even speculate that Einstein's reluctance to express an opinion on Poincaré's relativity paper might have been caused by his suspicion that Poincaré's final version published in 1906 in a second rate Italian journal could be less independent of his own work than the "Juillet 1905" at the end would make us believe.
For an alternative view, search for "Poincaré" in Wikipedia on Lorentz ether theory
The whole discussion in a comfortable format: de.sci.physik.narkive.com