Blog Ekkehard Friebe

Ich nehme Bezug auf meinen Blog-Eintrag: Nikolai Rudakov: „Establishment”. Aus dem dort genannten Buch (1981): „Fiction stranger than truth – In the metaphysical labyrinth of relativity” von Nikolai Rudakov bringe ich nachstehend eine weitere Leseprobe:

Zitat:

7 Relativity Postulate

In the introductory section of the 1905 paper Einstein, as has been mentioned in the preceding chapter, refers to the behaviour of conductors and magnets and the inability to discover any motion of the Earth relative to the aether. These two things, according to Einstein, suggest that there is no absolute rest and that the same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of mechanics hold good. Immediately after this sentence Einstein continues: We will raise this conjecture (the purport of which will hereafter be called the „principle of Relativity“) to the Status of a postulate. This is the first formulation of the relativity postulate which is one of the two basic premises on which the whole special theory rests. Einstein himself says that it is a conjecture. The meaning of conjecture is: an opinion without proof, or formed on the basis of insufficient evidence, or defective evidence, or no evidence at all.

Further down in the same paper the postulate is defined as follows: The laws by which the states of physical Systems undergo change are not affected, whether these changes of state be referred to the one or the other of two Systems of co-ordinates in uniform translatory motion. What is said here exceeds the bounds of the associated kinematical theory discussed by Einstein. In particular, the reference to laws and physical Systems is inappropriate because the Impression is created that we are entitled to deal with these things in a general way and that we know exactly what is meant by them. But Einstein has nowhere defined or disclosed what a physical System is and what exactly he means when he speaks of laws. All he talks about are abstract propositions concerning the motion of kinematical points. How these propositions are linked with physics is not revealed.

Another insufficiently clear expression is uniform translatory motion. In translatory motion every point of a moving system is „translated“ from one place in rigid space to another in the same direction and at the same speed. Translation excludes rotation and curved motion, but there is room for doubt whether it excludes rectilinear uniformly accelerated motion. However, it is usually assumed that Einstein has accelerationfree motion in mind as the numerous references in the kinematical part to velocity, constant velocity, uniform motion, etc. appear to imply. But although there is no specific mention of acceleration in the kinematical part, the introduction and the electrodynamical part of the 1905 paper certainly deal with phenomena which are not accelerationfree.

In his „fundamental“ 1905 paper Einstein does not make the slightest effort to clear up the ambiguity, or contradiction, concerning accelerationfree and accelerated motion, but in his 1907 paper On the Principle of Relativity and the Conclusions Drawn from it we find the following somewhat strange formulation of the relativity postulate: The laws of nature are independent of the state of motion of the reference System, at least if the latter is accelerationfree. What is the logical function of the words at least? Was Einstein still preferring to remain ambivalent, but slightly less than in 1905?

After Einstein produced his general theory of relativity in 1916 he published an 80-page popular exposition of both theories in 1917 under the title On the Special and the General Theory of Relativity. This work is still being reprinted to-day. It was translated into English in 1920 and published by Methuen under the title Relativity: the Special and the General Theory. In this work the relativity postulate of the special theory assumes the following form: If, relative to K, K’ is a uniformly moving co-ordinate system devoid of rotation, then natural phenomena run their course with respect to K’ according to exactly the same general laws as with respect to K. This definition still leaves the door open for rectilinear accelerated motion such as free fall towards a more massive gravitational System. The inevitable practical result of such motion is the termination of the independent existence of the less massive system.

The final form of the principle of special relativity is presented in Einstein’s Princeton lectures of 1921 which were published in the following year under the title The Meaning of Relativity. Acceleration is clearly eliminated in this form. Einstein now says that if K is an inertial system, then every other system K‘ which moves uniformly and without rotation relatively to K, is also an inertial system; the laws of nature are in concordance for all inertial Systems. The decisive word inertial has finally made its appearance. Only after the „success“ of his general theory in 1919, following the blessing by the Royal Society, Einstein found it necessary to remove the ambiguity. But by removing it and speaking openly of inertial Systems Einstein also admitted that his special theory had been dealing all along with fictional entities which have no place in physics and that the two crucial instances quoted at the beginning of the 1905 paper, electrodynamics and geodynamics, cannot be used as premises for his relativity postulate.

(Zitatende)

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Beste Grüße Ekkehard Friebe