Critique of the theory of relativity

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Criticism of the theory of relativity was expressed especially in the years after its publication on a scientific , philosophical , pseudoscientific and ideological level. Reasons for the criticism were own alternative theories, contradictions to existing theories, rejection of the abstract mathematical method, lack of understanding and alleged errors in the theory. Some of the ideological criticisms were motivated by anti-Semitism . Even today there are critics of the theory of relativity, who are also known as anti-relativists . However, their views are not taken seriously in the scientific community and are a form of science denial , since the theory of relativity is classified as free of contradictions and there are many experimental confirmations.

Note: This article assumes a basic understanding of the theory of relativity. For historical information see the history of special relativity .

Special theory of relativity

Relativity principle versus electromagnetic worldview

Especially through the work of Joseph Larmor (1897) and Wilhelm Wien (1900), the view was widespread that all forces in nature are of electromagnetic origin (“electromagnetic worldview”). This was confirmed by the experiments of Walter Kaufmann (1901–1903). Kaufmann measured an increase in mass with velocity approximately as it would if the mass were completely determined by the electromagnetic energy. Max Abraham (1902) drafted a theoretical interpretation of Kaufmann's results in which the electron was wrongly assumed to be rigid and spherical. It turned out, however, that this model was incompatible with the assumption referred to by Henri Poincaré (1902) as the principle of relativity , according to which an “absolute” movement of an observer relative to the ether (“ether wind”) should be undetectable. For this reason, Hendrik Antoon Lorentz (1904) created a model ( Lorentz's theory of ethers ) which largely fulfilled the principle of relativity, was in accordance with Kaufmann's experiments and was based on a dormant ether. In contrast to Abraham's theory, here the electron is subject to a shortening in the direction of movement ( Lorentz contraction ) and the time coordinates used by the observer moving in the ether depend on their respective location ( local time ). Both effects are contained in the so-called Lorentz transformation .

Abraham (1904) objected, however, that with a Lorentz contraction, non-electromagnetic forces are required to guarantee the stability of the electrons, which was unacceptable for representatives of the electromagnetic world view (a). And Abraham wrongly doubted that such a model, which obeyed the principle of relativity, could even be formulated without contradictions (b). Poincaré (1905) was able to show, however, that (b) was very compatible with the principle of relativity and a modified Lorentzian theory. Poincaré remained of the opinion that the mass was exclusively of electromagnetic origin, but he formally defined a non-electromagnetic potential (the so-called "Poincaré voltages"), which is subject to the Lorentz transformations and guaranteed the stability of the electrons with the assumed geometry. The electromagnetic worldview was consequently given up in favor of the principle of relativity. This development also corresponded to the special theory of relativity introduced by Albert Einstein in 1905 , in which the Lorentz transformation is derived from two postulates, namely the principle of relativity and the constancy of light. This theory concerns the nature of space and time itself, and is not limited to electromagnetic effects.

Experimental "refutations"

As described, Kaufmann's (1901–1903) measurements were compatible with both Abraham's and Lorentz's theory. In 1905 he carried out an even more precise series of experiments to bring about a decision between the theories. In the meantime, however, the theoretical situation had changed. Alfred Bucherer and Paul Langevin (1904) had developed another competing model, according to which the electron contracts on the one hand, but expands perpendicular to it, and thus the volume remains constant. And while Kaufmann was still evaluating the results of his measurements, Albert Einstein published the Special Theory of Relativity (SRT) in September 1905 , which was based on a radically new conception of the principle of relativity, according to which the ether does not exist at all and space and time are relative. As for the experimental predictions, however, the theory was equivalent to the ether theory of Lorentz and Poincaré. Kaufmann's results now seemed to confirm Abraham's theory and, to a lesser extent, the Bucherer-Langevin model, and spoke very strongly against the theories of Lorentz and Einstein. Kaufmann drew from this the conclusion that the “Lorentz-Einsteinian” basic assumption, namely the principle of relativity, had been refuted. Lorentz responded by saying that he was "at the end of his life", while Einstein did not comment on the results for the time being. However, others began to criticize the results in detail. Max Planck (1906) pointed to inconsistencies in the theoretical interpretation of the data and Adolf Bestelmeyer (1906) introduced new techniques which, especially in the lower speed range, provided different results than Kaufmann and raised doubts about Kaufmann's methods.

Bucherer (1908) therefore carried out new experiments and came to the conclusion that he had confirmed the “Lorentz-Einstein principle of relativity”, which Lorentz, Poincaré and Einstein registered with relief and satisfaction. But here, too, doubts about the method arose (especially from Bestelmeyer). Further experiments by Hupka (1910), Neumann (1914) and others seemed to have dispelled these doubts about the experimental results. However, later investigations (1938) showed that the execution of the Kaufmann-Bucherer-Neumann experiments had been inadequate from a modern point of view, and it was not until 1940 that the last doubts about the correctness of the Lorentz-Einstein formula could be dispelled with corresponding experiments. (However, this problem only affected this form of experiment. In investigations into the theory of spectra, the mass variability according to the Lorentz-Einstein formula could be confirmed very precisely as early as 1917. And in modern particle accelerators, the relativistic predictions for energy or mass are confirmed fast moving particles already routine.)

The experiments of Dayton C. Miller were then discussed . This was known for the fact that he carried out a series of repetitions of the Michelson-Morley experiment together with Edward W. Morley from 1902 to 1906 , which confirmed the negative result of the original experiment within the scope of the measurement accuracy. In 1921–1926, however, Miller carried out experiments that apparently gave positive results and consequently refuted the special theory of relativity or proved the existence of an ether in some form. Miller's experiments caused quite a stir, but were not taken very seriously in the professional world. B. Einstein's humorous comment ("God is clever, but he's not malicious.") Shows. Both Einstein and later Shankland criticized that Miller did not take the influence of temperature into sufficient account. And in a more modern analysis by Roberts it is pointed out that Miller made significant errors in the evaluation of the data (also due to the technical shortcomings of his time), and eliminating them would give a zero result. Furthermore, this supposedly positive result not only contradicted the older experiments, but they could not be reproduced in the further experiments of that time. In 1930 Georg Joos used an arrangement of similar dimensions to Miller's, and obtained a negative result. But that's not the only reason why Miller's results no longer play a role today: by using lasers and marsers in modern variants of the Michelson-Morley experiment, the effective path length of the light rays could be increased considerably - the results were and are all negative.

Acceleration in special relativity

Another objection to the theory of relativity was the question of whether accelerations can be dealt with within the framework of the special theory of relativity or how this can be reconciled with the concept of the rigid body . Max Born (1909) now developed a model in which the accelerated movement of rigid bodies was taken into account. This led to a paradox pointed out by Paul Ehrenfest : Due to the Lorentz contraction, the circumference of a rotating rigid body (a disk) would decrease, while the radius would remain the same ( Ehrenfest paradox ). Max von Laue (1911) showed, however, that due to the finite nature of the signal propagation in bodies, a rigid body is impossible in the special theory of relativity. That means: If a body is set in rotation, it would immediately lead to corresponding deformations. A similar thought experiment was also important for Einstein when he formulated the general theory of relativity (GTR), because he calculated that for a co-rotating observer, space assumes a non-Euclidean geometry.

Another example was the Sagnac effect . Here two signals are sent in opposite directions and then return again. If the arrangement is set in rotation, the interference fringes shift. Georges Sagnac (1913) believed to have proven the existence of the light ether. However, before that (1911) Laue was able to give the theory for this experiment within the framework of special relativity - corresponding explanations for special and general relativity were later given by Paul Langevin (1921, 1937). For a non-moving observer, the result is a natural consequence of the independence of the speed of light from the movement of the source. For a moving observer, it is the result of the acceleration during the rotation, as is also the case in classical mechanics, e.g. B. Foucault's pendulum . This is due to the fact that in accelerated reference systems the clocks lose their synchronization and the measured speed of light is no longer constant.

As Langevin (1911) and Laue (1913) showed, the twin paradox (or clock paradox) , which is often used against the special theory of relativity, also corresponds to this explanatory scheme: If two observers move away from each other and one of them is accelerated and thus leaves its inertial system in order to to return to others, the accelerated observer at the meeting will be younger than the one who rested all the time in his inertial system. It is therefore entirely possible to describe accelerated movements within the framework of the special theory of relativity, provided that the complications when changing the inertial systems are carefully considered. While observers in different inertial systems are completely equal in describing physical processes according to the theory of relativity, this no longer applies to accelerated movements.

However, as Einstein showed in 1908, gravity is an exception. While Poincaré, Abraham and others showed that gravity could in principle also be modified with methods of special relativity, these methods according to Einstein were incompatible with the equivalence principle of inert and heavy mass, according to which all bodies fall to the ground at the same speed. Einstein was also dissatisfied with another feature of special relativity, the preference for inertial systems over accelerated systems. When working out his theory of gravity, which takes all of this into account, Einstein had to replace the image of Euclidean space that still existed in the special theory of relativity with a non-Euclidean geometry and acquire the Riemannian geometry that formulated it, before he could complete the general theory of relativity in 1915 . One conclusion that Einstein drew as early as 1908 and 1911 was the deflection of light rays in the gravitational field and in accelerated reference systems. This deflection and the associated delay in propagation was described by Einstein as a departure from the constancy of the speed of light in a vacuum. Abraham (1912) objected, however, that Einstein had given the special relativity theory the "coup de grace" by departing from the constancy of light. Einstein (1912) replied that the special theory of relativity had limits of validity just like other physical theories (such as thermodynamics as a limit case of microscopic models of statistical mechanics, e.g. in the theory of Brownian motion ). However, it is still locally valid in his theory of gravity and can still be used with great accuracy in the case of relatively weak gravitational fields (practically in most cases). To explain this more precisely: In the special theory of relativity, the speed of light is constant in inertial systems, but not in accelerated systems (as already explained using the Sagnac effect). In the general theory of relativity it is locally constant, but in the case of large areas the curvature of space-time caused by a gravitational source influences the properties of scales and clocks as well as the propagation of light, B. leads to Shapiro delay .

Faster than light

In the special theory of relativity, the transmission of signals with faster than light speed is excluded. They would lead to violations of causality . Following an argument by Pierre-Simon Laplace , Poincaré pointed out in 1904 that Newton's theory of gravity had to be based on an infinitely fast, or at least much faster than the speed of propagation of gravity . Otherwise the planets would tumble into the sun on a spiral path due to the aberration of gravity . As early as the following year he showed that it is still possible to formulate a law of gravity in which gravity spreads with speed and which results in Newton's law of gravity as a limit case for small distances. In these circumstances, the orbit of planets remains stable. The general theory of relativity fulfills this condition.

Another apparent contradiction to light constancy is the fact that in dispersing media the group speed can be greater than . This was investigated by Arnold Sommerfeld (1907, 1914) and Léon Brillouin (1914), who came to the conclusion that in such cases the signal speed no longer corresponds to the group speed, but to the speed of the beginning of the signal (the front speed), which never exceeds c . Similarly, the results of the so-called " superluminal tunneling " by Günter Nimtz are classified by experts as compatible with the special theory of relativity, provided that the speed definition is carefully taken into account as discussed above.

The quantum entanglement (Einstein somewhat misleadingly referred to as "spooky action") was conceived partly as a seemingly light-fast phenomenon. According to this, entangled particles, regardless of their distance from one another, can no longer be described as individual particles with defined states, but only the entire system. By measuring the state of one particle, the state of the other particle is also determined, regardless of the distance at which it is located. However, due to the randomness of the measurement results, this phenomenon cannot be used directly for information transmission , but rather, as with quantum teleportation, the information must be transmitted in the classic way (and thus in accordance with the special theory of relativity).

Paradoxes

Insufficient knowledge of the fundamentals of the special theory of relativity, in particular the application of the Lorentz transformation in connection with length contraction and time dilation , led (and still leads) to the establishment of various apparent paradoxes . Both the twin paradox and the Ehrenfest paradox and their explanation have already been mentioned above. In addition to the twin paradox, the symmetry of time dilation (i.e. that, according to a special theory of relativity, each observer registers each other's clock more slowly than his own) led to fierce criticism, especially from Herbert Dingle , which was expressed in letters to scientific journals such as Nature from the late 1950s Years discharged. But the consistency of the symmetry of the time dilation can also be easily demonstrated , as was shown long before Dingle's criticism by Lorentz (1910), by observing the respective measurement rules and the relativity of simultaneity . Other well-known paradoxes are length contraction paradoxes and Bell's spaceship paradox , which can also be explained taking into account the relativity of simultaneity.

Ether and absolute space

For some physicists there was a certain uncertainty, especially in connection with the question of whether an ether was not needed after all to explain the at first glance paradoxical constancy of the speed of light in all inertial systems "dynamically". For example, Lorentz, Poincaré, Larmor, Oliver Lodge (1925), Albert A. Michelson (1927), Herbert E. Ives (1951), and Simon Jacques Prokhovnik (1963) kept the idea of ​​an ether as a preferred frame of reference. Various mathematicians and physicists such as Harry Bateman , Ebenezer Cunningham , Edmund Taylor Whittaker in England or Charles Émile Picard , Paul Painlevé in France also used ether as a preferred reference system in their first presentations on the special or general theory of relativity. This was related to the question of the extent to which Lorentz's theory of ether (with an ether at rest as the preferred but undetectable reference system in which an absolute time and an absolute space exist) differed from Einstein's special theory of relativity (where all these things no longer have any meaning) to be delimited. Because the Lorentz transformation is used in both theories, which makes them experimentally indistinguishable. Even Planck (1906) - as the most important promoter of the special theory of relativity in the early years - emphasized that Einstein's work was a generalization of Lorentz's theory ("Lorentz-Einstein theory"). Also, misunderstandings regarding Ehrenfest's paradox led some physicists such as Vladimir Varicak to believe that the length contraction in the special theory of relativity is only "apparent", in contrast to the "real" one in Lorentz's. In 1910 Einstein had to make it clear once again that the contraction of length is absolutely real as a measurable phenomenon in the special theory of relativity. However, the idea that on the one hand the aether takes the position of a preferred reference system with an absolute space and an absolute time and on the other hand this system should be completely undetectable due to an interplay of different effects, met with skepticism right from the start. And so it was a new generation of physicists like Einstein, Laue, Born, Ehrenfest, etc., who emphatically pointed out that in the special theory of relativity - as a completely new way of looking at space and time - there was no longer any room for an ether in the classical sense was.

In addition, Einstein also used the word “ether” in semipopular lectures to point out that in the special theory of relativity too, space-time has an “absolute” existence that is independent of matter. And due to the inapplicability of Mach's principle , the term “ether” can still be used in the general theory of relativity - but here space-time can also be influenced by matter, so this ether can no longer be described as absolute. However, as Einstein pointed out, this term has practically no longer any correspondence with the classical ether due to the lack of a state of motion. Because of this, this terminology was later not adopted by experts (and even by Einstein himself). Likewise, the attempt by Paul Dirac (1953) to move the quantum vacuum into the vicinity of an ether equipped with a state of motion (which is only available in rudimentary form) was not successful. George F. Smoot (2006) explained that the frame of reference in which the cosmic microwave radiation is isotropic could be called ether (“New Ether Drift Experiments”). However, Smoot made it clear that there is no contradiction to the special theory of relativity, since this apparent ether wind has no influence on the laws in the inertial systems (as was shown in the Michelson-Morley experiment ) and this preference for a reference system is therefore only used to simplify the description of the Expansion of the universe takes place. Therefore, in modern physics the classical aether equipped with a state of motion is no longer used.

Alternative theories

As a counter-model to the theory of relativity, the thesis founded by George Gabriel Stokes (1844) that aether was carried along was continued (e.g. by Philipp Lenard and others). It was believed that this could explain various effects in a “clear” way. However, the transport of the ether was faced with great difficulties from the start. This was especially true for the aberration , which should actually only occur with a dormant ether. To explain this effect, it had to be assumed that the aether is rotation-free and incompressible, but both effects could not be converted into a synthesis in a compatible way. In addition, the complete entrainment contradicts the Sagnac effect and the Fizeau experiment . As a way out, it was suggested that the entrainment caused by gravity and thus proportional to the mass of the body. The resulting condensation of the ether should explain the aberration, and also the negative result of Michelson-Morley (according to which the great mass of the earth carries the ether completely with it) as well as the positive results of Sagnac and Fizeau (according to which the small masses of the apparatus only lead a small amount of ether with itself) became compatible with one another. But even this hypothesis was taken ad absurdum by the Michelson-Gale-Pearson experiment , because here the rotation of the earth itself could be determined with the help of the Sagnac effect, which would not have been expected with an ether entrainment - another explanation would have further Auxiliary hypotheses are required, etc. A mathematically complete theory of ether entrainment (or of the ether itself at all) was never developed because of these increasingly fantastic ethereal properties. Consequently, this model never represented a serious alternative, since the experiments of Michelson-Morley, Fizeau, Sagnac etc. can be explained comparatively easily and without additional assumptions with the help of the theory of relativity.

Also out of dissatisfaction with the postulate of constant light, some like Walter Ritz turned to an emission theory of light. According to this, the speed of the light source is added to that of the light according to the Galileo transformation , whereby the concept of the light ether was rejected. Thus the negative results of the ether drift experiments like the Michelson-Morley experiment could be explained quite easily. However, this theory has never been fully elaborated because the basic assumptions lead to conflicting consequences as observed. For example, if the emission theory were to be valid, distortions should have occurred in the observed orbits, but observations of binary stars could not reveal such distortions. The Sagnac effect also contradicts a dependency on the light source, and no source dependency could be determined in modern measurements in particle accelerators . In addition, Maxwell- Florentz electrodynamics, which has been extremely successful to this day (and its further development as quantum electrodynamics ) would have to be dispensed with.

general theory of relativity

General covariance

While Einstein still believed in 1916 that Mach's principle was completely fulfilled in the GTR (i.e. the gravitational field should be completely determined by the gravitational sources), Willem de Sitter (1916) showed that this requirement could not be fulfilled within the framework of the general theory of relativity. Because the “gravito-inertial field”, which describes the gravitational and inertial effects, also has an existence independent of the source in the general theory of relativity . Einstein, who initially resisted this knowledge, finally accepted this, which is why he also used the word ether for the gravitational field of the GTR in some lectures (although this expression did not catch on). Associated with this was a turning away from the relativity of acceleration, because as Erich Kretschmann (1917) showed, this does not automatically follow from general covariance  either - because with the appropriate mathematical effort, every theory (even Newtonian mechanics ) can be formulated in general covariant . And so in the general theory of relativity, due to the independent existence of the gravito-inertial field with two observers accelerated relative to each other, it can be determined which of the two is moving “really” or “absolutely” non-uniformly. However, Einstein emphasized that the conditions here are by no means the same as in Newtonian physics, because in the general theory of relativity the source acts back on the gravito-inertial field. Furthermore, this "absolute" acceleration in no way implies the existence of an absolute or general relativity substantialist interpretation of the room or the space-time itself. When still out philosophical debate on spacetime substantialism (spacetime substantivalism) and space-time relationism (spacetime relationalism) Physicists and philosophers of science such as John Earman , John D. Norton and John Stachel have put forward strong reasons for accepting relationism.

The Bad Nauheim Debate

In the "Bad Nauheim Debate" (September 1920) between Einstein and Philipp Lenard at the meeting of German naturalists and doctors, the latter made the following objections (although the published descriptions of this discussion are partly incomplete): He criticized the lack of " Visualization ”in the theory of relativity, whereby this can only be achieved through the assumption of the ether theory. Einstein replied that the contents of "clarity" or "common sense" have grown and changed over time, so that they cannot be used as criteria for the correctness of a theory. Lenard also interjected that Einstein had reintroduced ether in general relativity. This was z. B. rejected by Hermann Weyl , because although Einstein actually used this expression, he only alluded to the fact that space-time in GTR also has properties; however this has little to do with the classical ether, since no state of motion can be applied to it. Lenard also interjected that the general theory of relativity allows faster than light speeds. For example, in a rotating frame of reference in which the earth rests, the more distant parts of the universe would rotate around the earth at many times the speed of light. As Weyl explained, however, extended rotating systems cannot be understood as rigid bodies (neither in the special nor in the general theory of relativity), so that the signal speed does not exceed the speed of light here either. Another objection raised by both Lenard and Gustav Mie concerns the existence of "fictitious" gravitational fields, which were introduced in general relativity in accelerated frames of reference to ensure equivalence with systems in which real gravitational fields occur. Lenard and Mie objected that the principle of relativity can only be valid for forces that were generated by real masses, but not for fictitious gravitational fields. Einstein replied that based on Mach's principle , the fictitious gravitational fields can also be ascribed to real, distant masses. In fact, this objection by Lenard and Mie was justified, because Mach's principle ( see above: Section “General covariance”) and thus also the relativity of acceleration is not completely fulfilled in general relativity.

Silberstein-Einstein controversy

Ludwik Silberstein , who was originally a supporter of the special theory of relativity and made important contributions, interjected in 1920 that the deflection of light by the sun, as described by Arthur Eddington et al. a. (1919) was found, does not necessarily represent a confirmation of the general theory of relativity, but can also be explained with the help of an ether that is completely carried along by the sun. Such theories were rejected, however, because they contradict the existence of the aberration of light ( see: Chapter "Alternative Theories"). And in 1935 Silberstein believed to have found a contradiction in the two-body problem of general relativity, but this was immediately rejected by Einstein and Rosen.

Philosophical Criticism

The claim of the theory of relativity to have revolutionized the conventional concepts of space and time, as well as the introduction of a non-Euclidean geometry within the framework of the general theory of relativity, met with criticism from many philosophers from different schools. A characteristic of many philosophical criticisms, however, was an insufficient knowledge of the mathematical-formal principles and statements of the theory of relativity, which often missed the point. The theory of relativity was misunderstood as a form of relativism by philosophical as well as popular science (often simply because of the similarity of names) - which was true for many critics as well as for some followers such as the phenomenalist Joseph Petzoldt . However, this is misleading because, e.g. B. Einstein, Planck, and others have shown that space and time are relativized and the equality of the reference systems is sought, but the invariance ( invariance ) of certain natural laws and the speed of light are postulated. Einstein himself originally preferred the term “invariant theory” used by Felix Klein (1910) and was initially skeptical of the term “relative (itäts) theory” coined by Planck (1906).

Kantianism, phenomenology

Critical statements on the theory of relativity were given from the ranks of Neo-Kantianism by philosophers such as Paul Natorp , Bruno Bauch , Ernst Marcus , Salomo Friedlaender , Jonas Cohn , Lenore Kühn . While some only rejected the philosophical consequences of the theory of relativity, others concluded that the physical theory itself was falsehood. Einstein was accused of a " categorical error ": the derivation of the curvature of space from matter and energy phenomena is not possible, since this already defines space as one a mere view category (in the sense of Immanuel Kant ) would be a prerequisite. The same applies to the relationship between absolute and relative - the relativization of space and time can only be carried out against the background of an absolute time and an absolute space. Arguments similar to those of the Neo-Kantians came from representatives of phenomenology such as Oskar Becker , Paul F. Linke , or Moritz Geiger . The objections raised included: the three-dimensionality of space cannot be overridden; the relativity of simultaneity contradicts an ideal concept of time that is constitutive for our access to the world.

Klaus Hentschel describes the approach taken by neo-Kantians and phenomenologists (namely the shifting of space, time, geometry, etc. into an empirically uncheckable area) as an "immunization strategy" with which any criticism of Kantianism is blocked from the outset. In addition, the Neo-Kantians would have overlooked the fact that Kant's philosophy can also be viewed as a product of its time - namely as based on the philosophy of the 18th century. prevailing Newtonian world system, the foundations of which were made by Kant to a priori necessary preconditions of experience. That is why neo-Kantian supporters of the theory of relativity such as Ernst Cassirer or Hans Reichenbach emphasized that the content of the "a priori knowledge" established by Kant (absoluteness of space and time, Euclidean geometry) can no longer be maintained and must be modified by the findings of the theory of relativity. Reichenbach subsequently drew the general conclusion that Kantianism was to be rejected and turned to logical empiricism .

Conventionalism, protophysics

As for the criticisms of representatives of conventionalism , Henri Poincaré was, as the founder of this school of thought, an important precursor of the theory of relativity. He was of the opinion that the simultaneity of events in different places was merely a convention made by agreement; He formulated the principle of relativity and gave a method for clock synchronization based on the constancy of the speed of light. On the other hand, he repeatedly emphasized that both Euclidean geometry and the classical definitions of space and time would always remain the most convenient conventions in the context of physics. Taking up this last line of thought, there is a pronounced criticism of the theory of relativity in Pierre Duhem and especially Hugo Dingler . Dingler insisted on the preference for Euclidean geometry and the concept of rigid bodies, which in his view could be operationally justified, as well as Newton's law of gravitation as a prime example of a simple theory. In contrast to Poincaré, Dingler was of the opinion that these determinations are not only made for reasons of convenience, but are based on conditions that actually exist in reality. Dingler's interpretation was immediately rejected by representatives of logical empiricism such as Rudolf Carnap , Reichenbach and Moritz Schlick . It was argued that Poincaré's original conventionalism could be modified in the sense of the theory of relativity if one adds a stronger empirical component to this model. It is true that the fundamentals of Newtonian physics are simpler, but these can only be adapted to the empirical results with additional auxiliary hypotheses. In contrast to this, the basic assumptions of the general theory of relativity are more complicated, but here all phenomena can be explained without auxiliary hypotheses, which makes the theory in its entirety even simpler than Newtonian physics.

On the basis of some of Dingler's basic assumptions, Paul Lorenzen and Peter Janich in particular represented so-called protophysics in the context of Erlangen's constructivism . The protophysicists deny that empirical results can revise measuring device standards, which are the prerequisites for measurements. The criticism of the usual interpretation of the theory of relativity is a recording of the conventionalistic aspects of the early standard work Gravitation and Cosmology by Steven Weinberg . Lorenzen sees in the metric tensor of the field equations of Einstein and Hilbert only a mathematical description for the conversion of the pseudo-Euclidean proportions in inertial systems to non-uniformly moving reference systems. Not the space is considered to be curved, but as compared to Euclidean geometry as a basis the light (of the general theory of relativity in accordance) flows for example in strong gravitation fields crooked . This is an outsider interpretation of general relativity. The majority opinion among physicists is that relativistic geometry should not be restricted to local effects and that it describes true space.

More philosophical reviews

Some advocates of the philosophy of life , vitalism and critical realism (such as Henri Bergson and Aloys Wenzl ) argued that there was an essential difference between physical and biological - psychological time. The time dilation and thus the twin paradox could therefore not be extended to biological organisms and psychological phenomena. (However, not all representatives of these directions shared this assessment; for example, the critical realist Bernhard Bavink assessed the theory of relativity positively). Bergson also believed that once a reference system had been selected to describe the phenomena, the values ​​determined there would apply “absolutely”, while all others were only “fictitious”. In contrast to Bergson's opinion, from the point of view of the special theory of relativity (as e.g. André Metz showed), however, there is no reason not to extend the time dilation to organisms, and in the twin paradox Bergson also overlooked the asymmetrical acceleration.

Criticisms that can be assigned to fictionalism were z. B. developed by Oskar Kraus or Aloys Müller . The basic assumptions about the constancy of the speed of light, local time, length contraction, or non-Euclidean geometry should only be fictitious. Taken together they would give the mathematical appearance of consistency, but in fact they do not belong to any reality. Space and time are also essentially different and cannot be combined into one space-time . The fictionalist approach was immediately criticized by Aloys Wenzl and others. Many statements in the theory of relativity, such as the principle of equivalence, are very well confirmed empirically, and the constancy of the speed of light and the relativistic effects are by no means contradictory, but complementary to each other.

Philosophical criticism was also exercised in the Soviet Union (mainly in the 1920s) on the basis of dialectical materialism . The theory of relativity was classified as anti-materialistic and speculative, and a mechanical worldview corresponding to "common sense" was required as an alternative. (However, there were also philosophers who saw dialectical materialism as compatible with the theory of relativity). However, these attacks were often based on a superficial understanding of the theory of relativity and were rejected by experts in the field as flawed and not to be taken seriously. Also on the basis of dialectical materialism in the People's Republic of China in the time of the Cultural Revolution (between 1966 and 1976), the theory of relativity was subjected to an organized criticism and rejected as too "western" and "idealistic-relativistic".

Relativity hype and public criticism

Although Planck compared the upheaval caused by the theory of relativity as early as 1909 with the Copernican turn and the special theory of relativity began to prevail among theoretical physicists from 1911 or had already established itself, it was only the experimental findings of a group around Arthur Stanley Eddington (1919) that led to a worldwide triumphant advance the theory of relativity. In the mass media Einstein was also publicly placed in line with Nikolaus Kopernikus , Johannes Kepler and Isaac Newton and celebrated as a revolutionary in physics. This fame led to a public "relativity hype", but also triggered a backlash from some scientists and scientific laypeople in the culturally pessimistic mood of the post-war period. This dispute was (atypical for scientific discussions) also partly conducted via the mass media, whereby the criticism referred not only to the theory of relativity, but also to Einstein himself.

Academic and non-academic criticism

Some academic scientists, especially experimental physicists, such as Nobel Prize winners Philipp Lenard and Johannes Stark , as well as Ernst Gehrcke , Stjepan Mohorovičić and Rudolf Tomaschek criticized the strong mathematization of the theory of relativity, especially by Minkowski, as a tendency towards abstract theory formation , which goes hand in hand with the loss of the " common sense ”. Here, anti-relativistic experimental physicists believed their discipline was in danger. In fact, the theory of relativity marks the point in the history of science at which perception as a means of physical understanding of natural phenomena fundamentally failed for the first time. In contrast to this, as described above, Lenard, Gehrcke, Mohorovičić etc. tried to revive the old idea of ​​a completely carried ether. However, these theories, which are mostly only qualitative, never formed serious competition for the modern models based on relativity and quantum theory. Opinions clashed when a discussion between Einstein and Lenard took place at the natural scientist conference in Bad Nauheim on September 23, 1920, which caused considerable public attention (see above).

In addition, there were mainly critics (with or without physical education) who were very far removed from the content of the recognized academic world. These were mostly people who had already developed their own models before the relativity theory was published, which were supposed to solve some or even all of the world's puzzles in a simple way. Wazeck introduced the term “world puzzle solver” for these “free researchers” like Hermann Fricke , Rudolf Mewes, Johann Heinrich Ziegler , Arthur Patschke, etc. with reference to Ernst Haeckel's “Die Weltträthsel” . Their views and models had their quite different roots mostly in monism , in life reform or in occultism . Their methods were characterized by the fact that they rejected practically all terminology as well as the (predominantly mathematical) methods of the professional world. They mostly published their work in private publishers and popular science or non-specialist journals. For many world puzzle solvers (especially the monists) it was characteristic of the attempt to explain as many phenomena as possible through clear mechanical (or electrical) models, which was also expressed in their defense of the ether. Like some experimental physicists, they consequently rejected the lack of illustration of the theory of relativity, which was viewed as a subtle calculation that could not uncover the real causes behind things. An example is the pressure theory of gravity , which was widespread in the non-academic environment at the time . Here an association was formed in Breslau from 1870 onwards. a. The model represented by Anderssohn (1880) and later by Patschke (1920), according to which the force of gravity is caused by the ether pressure or “mass pressure from a distance”. On the other hand, the pressure theories of Georges-Louis Le Sage and Caspar Isenkrahe , which are also discussed in the professional world, were only mentioned sporadically by the world puzzle solvers . The pressure theory was seen as a vivid alternative to the abstract mathematical gravitation theories of Newton and Einstein. The enormous self-confidence of the world puzzle solvers is remarkable, who not only believed they had solved all the puzzles, but also had the expectation that they would quickly establish themselves in the professional world, which, however, did not come true.

Since Einstein seldom defended himself against the critics, this was adopted by other relativity theorists who (according to Hentschel) formed a kind of "defender belt" around Einstein. Important representatives on the physical level were e.g. B. Laue and Born, and on the philosophical-popular scientific level z. B. André Metz and especially Reichenbach, who in the 1920s often grappled with the critics in various newspaper articles. However, these discussions mostly failed in the beginning. Physicists like Gehrcke, some philosophers, and the world puzzle solvers were so convinced of their own ideas that they were often unable to empathize with the theory of relativity. Because of this, distorted images of the theory were often designed (though supported by misleading popular scientific presentations by some supporters of the theory of relativity), which were then "refuted" by the critics. Another reason was, of course, that a substantial criticism failed due to the lack of mathematical skills of many critics. While the world puzzle solver was not taken seriously by the professional world from the outset, even important physicists such as Lenard and Gehrcke were pushed into an increasingly outsider role. However, they did not assume that this was due to the shortcomings in their work, but various conspiracy theories were developed according to which the relativistic physicists (in the 20s and 30s increasingly also the Jews ) would have allied to suppress the truth, and to be able to maintain their own positions in academic operations. Gehrcke z. B. attributed the spread and effect of the theory of relativity from 1920 to 1924 to a kind of mass suggestion , for which he had a clipping service collect around 5000 newspaper articles (2700 of which have been preserved) on this subject. However, this was countered by the fact that the mere existence of the relativity hype has absolutely no significance for the validity of the theory, and consequently cannot be used for, but also not against, the theory of relativity.

Some critics now tried to improve their position vis-à-vis the professional world by forming groups of critics. Probably the most important was the "Academy of Nations", which was founded in the USA in 1921 by Robert T. Browne and Reuterdahl and to which Thomas Jefferson Jackson See , Gehrcke, Mohorovičić and others soon also belonged. However, the association dissolved a few years later around 1930 without having had any great effect.

Chauvinism and anti-Semitism

Shortly before and during the First World War, there were isolated nationalist criticisms of the theory of relativity, especially in France. Both Planck's quantum theory and Einstein's theory of relativity were classified by Pierre Duhem and others as products of the too “formal-abstract” German mind and as an attack on common sense. Analogous to this, the partly organized public criticism in the Soviet Union and China must also be cited, which rejected the theory of relativity as "western decadent" not for objective reasons, but ideologically motivated.

While for these critics the Germans or the West served as the enemy, in Germany it was conversely the Jewish origins of Einstein, Hermann Minkowski and other proponents of the theory of relativity that served as a target for ethnically -minded opponents. Paul Weyland , who worked as an anti-Semite and nationalist agitator in the 1920s , organized the first public events in Berlin in 1919 that took a stand against the theory of relativity, and founded a “Working Group of German Naturalists for the Preservation of Pure Science”, with Weyland himself possibly the only one Was a member. While von Weyland still avoided anti-Semitic statements in the published texts, it was already clear to many that anti-Semitism played a role (as some letters from Lenard from 1920 onwards showed). Reacting to these subliminal moods, Einstein publicly suspected that the criticisms from Weyland, Gehrcke and others were also anti-Semitically motivated. Some critics reacted indignantly to Einstein's accusation, alleging that such allegations of anti-Semitism were only used to silence the critics. From now on, however, public anti-Semitic statements were made against Einstein and the representatives of the theory of relativity and modern physics (of course, this does not apply to all critics of the theory of relativity).

In his criticism, Theodor Fritsch (1921) emphasized the allegedly negative effects of the Jewish spirit in the theory of relativity, and the right-wing press carried on this agitation unchecked. After the murder of Walther Rathenau and death threats against Einstein, he even left Berlin for some time. Gehrcke's book Die Massensuggestion der Relatitätstheorie (1924) was not itself anti-Semitic, but the theses it contained were praised by the right-wing press as representing allegedly typically Jewish behavior. In 1922 Lenard spoke of the “foreign spirit” as the background to the theory of relativity, whereby he himself joined the NSDAP in 1924 and Stark in 1930 . Both propagated what is known as German physics , which only accepted scientific findings that are based on experiments and accessible to the senses . According to Lenard (1936), this physics is an “Aryan physics or physics of people of Nordic nature”, in contrast to the supposedly formally dogmatic “Jewish physics”. Other pronounced anti-Semitic criticisms can be found among others. a. with Wilhelm Müller , Bruno Thuringia and some world puzzle solvers like Reuterdahl, Ziegler and Mewes. Müller got into fantasies such as that the theory of relativity is a purely “Jewish matter”, that it corresponds to the “Jewish being”, etc., while Thuringia made absurd comparisons between the Talmud and the theory of relativity.

Plagiarism allegations or priority discussions

Critics like Lenard, Gehrcke and Reuterdahl also called Einstein a plagiarist or at least questioned his priority. The purpose of this was, on the one hand, to show the possibility of non-relativistic alternatives to modern physics, and on the other hand, Einstein himself should be discredited. It turned out, however, that both the derivation and the physical content of the theory of relativity differ fundamentally from the previous models, which shows that these allegations are untenable. Some examples:

  • Johann Georg von Soldner (1801) became known for his calculations of the deflection of light by celestial bodies, but his theory was based on Newton's corpuscle theory and had nothing in common with Einstein's derivation in the context of general relativity.
  • The same is true for Paul Gerber (1898), who derived a formula for the perihelion of Mercury that corresponds to that of Einstein. Gerber's theory, however, is a purely classical theory without any connection with the basic statements of the theory of relativity. Moreover, it has already been refuted, since it predicts too great a deflection of the light rays in the gravitational field, and even Gerber's prediction of perihelion rotation leads from a modern perspective to an incorrect value if the relativistic mass is taken into account.
  • With the Voigt transformation, Woldemar Voigt (1887) created a preliminary form of the Lorentz transformation. However, as Voigt himself later emphasized, this was based on an elastic light ether theory and not on the electromagnetic light theory as used by Lorentz and Einstein. What both light theories have in common, however, is that they are based on partial differential equations that allow only transverse waves as harmonic solutions (i.e. no longitudinal waves ).
  • Friedrich Hasenöhrl (1904) applied the concepts of electromagnetic mass and impulse (i.e., electromagnetic energy contributes to the mass of a body), known long before him, to cavity and thermal radiation. Einstein's equivalence of mass and energy goes much further, however, as it is derived from the principle of relativity and encompasses any form of energy (not just electromagnetic).
  • In 1901 the philosopher Menyhért Palágyi developed a "space-time theory" with an imaginary time coordinate as the fourth dimension. In terms of content, however, Palágyi's philosophy was not in agreement with the theory of relativity, because (as Palagyi himself emphasized) it actually only represented a reformulation of the classical context.
  • Added to this were the allegations of the world puzzle solvers such as Reuderdahl, Mewes, Ziegler , etc., who believed they recognized plagiarism even with only verbal correspondence between some of the text passages in their works and those of Einstein. On the one hand, the world puzzle solvers raised allegations of plagiarism, and on the other hand, fundamental criticism of the theory of relativity was exercised. In order to justify this contradicting approach, it was assumed that Einstein stole various contents, did not understand them and consequently merged them into the "illogical" theory of relativity. In the process, conspiracy theories were developed that were supposed to explain how Einstein even got hold of the often not easily accessible works of the world puzzle solver, or why this was tolerated by the professional world.

In contrast to these baseless accusations, modern historians of science occasionally pursue the question of whether Einstein was possibly influenced by Poincaré, who proposed similar interpretations of Lorentz's electrodynamics that can also be found in the special theory of relativity.

A hundred authors against Einstein

A compilation of various reviews is the brochure Hundert Authors gegen Einstein published in 1931 . It contains very brief works by 28 authors and excerpts from publications by 19 other authors. The rest consists of a list, including people who only occasionally expressed critical objections to the theory of relativity. In addition to philosophical objections, this volume also cited alleged contradictions in the theory of relativity. Reichenbach described the book as an "astonishing accumulation of naive mistakes" and as "unintentionally funny". Albert von Brunn described the content as a relapse into the 16th and 17th centuries, and Einstein himself said: "If I were wrong, a single author would be enough to refute me." For Hubert Goenner , the contributions represent a mixture of mathematical -physical incompetence, hubris and the feeling of being suppressed and censored by the physicists. According to Goenner, the compilation of the authors shows that this is not a reaction within the physicist community - only one physicist ( Karl Strehl ) and three mathematicians ( Jean-Marie Le Roux , Emanuel Lasker and Hjalmar Mellin ) were represented - but one inadequate reaction of the academically educated bourgeoisie, which did not know what to do with the theory of relativity. The average age of the authors is also significant: 57% were significantly older than Einstein, a third were roughly the same age, and only two people were significantly younger. Two authors (Reuterdahl, von Mitis) were anti-Semites and four others may have been involved with the Nazi movement. On the other hand, some authors ( Salomo Friedländer , Ludwig Goldschmidt, Hans Israel, Lasker, Oskar Kraus , Menyhért Palágyi ) were of Jewish origin.

Status of criticism

Opponents of the theory of relativity find from time to time headlines such as "Einstein refutes" resonance in the press. In most cases, it is about experimental set-ups or thought experiments that in no way deal with the theory of relativity, but only “refute” parts of its visual, concrete, popular scientific interpretations. Due to the poor scientific quality identified in the peer review , critical papers are only accepted in exceptional cases by specialist journals and instead published in private publishers, alternative journals (such as Raum & Zeit , Apeiron, Galilean Electrodynamics) or private websites. In addition to the lack of understanding of the anti-relativists, the large number of experimental successes and confirmations of the theory of relativity is the decisive reason why the scientific community no longer takes criticism seriously. Examples of such reviews rejected by experts are Louis Essen (1971), Walter Theimer (1977) and Galeczki / Marquardt (1997). The criticisms therefore no longer play a role in current scientific research and are usually only mentioned in historical-philosophical studies.

Technological progress leads to ever more accurate ways to check the theory of relativity. So far it has withstood all these tests unscathed. In addition, further research is being carried out in the theoretical field. The attempt is made to unite quantum physics with general relativity to form a theory of quantum gravity . The currently most promising models for this are string theory and loop quantum gravity . Both theories have a relativistic basis, but small deviations from the predictions of the relativity theory, such as violations of the Lorentz invariance, would be possible. So far, however, such deviations could not be proven experimentally.

literature

Historical analysis

  1. ↑ a b c d e f Miller (1981)
  2. ↑ a b Pais (1982)
  3. ↑ Katzir (2005)
  4. ↑ Janssen (2007)
  5. ↑ a b c d Pauli (1921)
  6. ↑ a b Staley (2009)
  7. ↑ Swenson (1970)
  8. ↑ a b Paty (1987)
  9. ↑ Zeilinger (2005)
  10. ↑ Chang (1993)
  11. ↑ Mathpages
  12. ↑ Warwick (2003)
  13. ↑ Janssen (2008)
  14. ↑ Kragh (2005)
  15. ^ Norton (2004)
  16. ↑ Janssen (2008)
  17. ^ Norton (1993)
  18. ^ Huggett (2009)
  19. ^ Norton (2008)
  20. ↑ Goenner (1993a)
  21. ↑ Havas (1993), pp. 97-120
  22. ↑ Hentschel (1990), pp. 92-105, 401-419
  23. ↑ Hentschel (1990), pp. 199-239, 254-268, 507-526
  24. ↑ Hentschel (1990), pp. 293-336
  25. ↑ Zahar (2001)
  26. ↑ Hentschel (1990), pp. 240-243, 441-455
  27. ↑ Hentschel (1990), pp. 276-292
  28. ↑ a b c d e f g Hentschel (1990)
  29. ↑ a b Vizgin / Gorelik (1987)
  30. ↑ a b Hu (2007)
  31. ↑ a b c d Goenner (1993a)
  32. ↑ a b c d e f g Wazeck (2009)
  33. ↑ Kleinert (1979)
  34. ↑ Beyerchen (1982)
  35. ↑ Posch (2006)
  36. ↑ Darrigol (2004)
  37. ↑ Leveugle (2004)
  38. ↑ Goenner (1993b)

Work on relativity theory

  1. ↑ Lorentz (1904)
  2. ↑ a b Poincaré (1906)
  3. ↑ Planck (1906b)
  4. ↑ Bucherer (1908)
  5. ↑ Einstein (1905)
  6. ↑ Roberts (2006)
  7. ↑ Born (1909)
  8. ↑ Laue (1911)
  9. ↑ a b Laue (1921a)
  10. ↑ Langevin (1921)
  11. ↑ Langevin (1911)
  12. ↑ Einstein (1908)
  13. ↑ Einstein (1912)
  14. ↑ Einstein (1916)
  15. ↑ Carlip (1999)
  16. ↑ Sommerfeld (1907, 1914)
  17. ↑ Brillouin (1914)
  18. ^ Wallenborn (1999)
  19. ↑ Planck (1906ab)
  20. ↑ Varicak (1911)
  21. ↑ Einstein (1911)
  22. ^ Smoot (2006)
  23. ↑ Dirac (1953)
  24. ↑ Joos (1959), p. 448
  25. ↑ Michelson (1925)
  26. ↑ DeSitter (1913)
  27. ↑ Fox (1965)
  28. ↑ Einstein (1916)
  29. ↑ DeSitter (1916ab)
  30. ↑ Kretschmann (1917)
  31. ↑ Einstein (1920, 1924)
  32. ↑ Einstein / Rosen (1936)
  33. ↑ Klein (1910)
  34. ↑ Petzoldt (1921)
  35. ↑ Planck (1925)
  36. ↑ Reichenbach (1920)
  37. ^ Cassirer (1921)
  38. ↑ Schlick (1921)
  39. ↑ Reichenbach (1924)
  40. ↑ Weinberg (1972)
  41. ↑ Metz (1923)
  42. ↑ Einstein (1920a)
  43. ↑ Laue (1917)
  44. ↑ Laue (1921b)
  45. ^ Mattingly (2005)
  46. ↑ Will (2006)
  47. ↑ Liberati (2009)

Critical work

  1. ↑ Abraham (1904)
  2. ↑ Kaufmann (1906)
  3. ↑ Miller (1933)
  4. ↑ Ehrenfest (1909)
  5. ↑ Sagnac (1913ab)
  6. ↑ Abraham (1912)
  7. ↑ Poincaré (1904)
  8. ↑ Dingle (1972)
  9. ↑ Lodge (1925)
  10. ↑ Michelson (1927)
  11. ↑ Ives (1951)
  12. ↑ Prokhovnik (1963)
  13. ↑ a b Lenard (1921a)
  14. ^ Ritz (1908)
  15. ↑ Lenard, Einstein, Gehrcke, Weyl (1920)
  16. ↑ Silberstein (1936)
  17. ↑ Natorp (1910)
  18. ↑ Left (1921)
  19. ↑ Friedlaender (1932)
  20. ↑ Dingler (1922)
  21. ↑ Lorenzen (1976, 1977)
  22. ↑ Bergson (1921)
  23. ↑ Kraus (1921)
  24. ↑ Gehrcke (1924a)
  25. ↑ Mohorovičić (1923)
  26. ↑ Fricke (1919)
  27. ↑ Patschke (1922)
  28. ↑ Mewes (1920)
  29. ↑ Ziegler (1920)
  30. ↑ Gehrcke (1924b)
  31. ↑ Reuterdahl (1921)
  32. ↑ Lenard (1936)
  33. ↑ Stark / Müller (1941)
  34. ↑ Thuringia (1941)
  35. ↑ Gehrcke (1916)
  36. ↑ Lenard (1921b)
  37. ↑ Israel et al. (1931)
  38. ↑ Essen (1971)
  39. ↑ Theimer (1977)
  40. ↑ Gałeczki / Marquardt (1997)
  41. ↑ Apeiron homepage
  42. ^ Galilean Electrodynamics. ( Memento of May 10, 2009 in the Internet Archive ).

Web links

  • The newspaper clippings and papers collected by Gehrcke and Reuterdahl form an important basis for historical work on the criticism of the theory of relativity: