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Ernst Mach

burg on Dcccmber 14, 1919: “Dr. Dinglcr once visitcd me in Haar, and I learncd a grcat dcal from that convcrsation. Dingler does not draw thc same conscquences as Einstein docs from the deviation of light rays in the gravitational field of thc sun, a dcviation which is said to have bccn established bcyond objcction.”

According to Ludwig Mach, his father did not want any of his books rcviscd after his dcath, but he had no objcction to spccial "forewords" or “afterwords” by pcople interested in his ideas.⁷⁴ For this reason Ludwig Mach had no initial objcction to Pctzoldt’s pro-Einstein after-word but on discovering its contcnts Ludwig tried to balancc it with a foreword by Hugo Dingler.⁷⁵ Pctzoldt, who bclieved that Ernst Mach still intended that hc, Petzoldt, should continuc to be thc litcr-ary executor of his works (as Petzoldt had carlier been with the books of Avenarius) disrcgardcd Ludwig Mach’s suggestion.™

Mach’s son allowcd dic afterword to appear, but at the same time pointed out that in a supplemental contract his father had madę him responsible for thc publication of all of Ernst Mach's books.⁷⁷ In addition, Ludwig Mach had his fathcr’s The Principles of Physical Optics (Part I) published in the same ycar as Pctzoldts afterword appeared, that is, in 1921. Rcaders around thc world werc now faccd with two simultnncously published books by Mach, one with his own preface in which he denouneed Einstein’$ theory, and another with an afterword written by a longtimc philosophical ally which favored the theory and asserted that Mach was a forerunner of it.

Petzoldt was upset by thc anti-Einstcin preface and threatened to bring thc 1914 corrcspondcncc problem into thc open if Ludwig Mach attempted to publish a disclaimcr he wished to add to thc next cdition of Mach’s hiechanies to undcrminc the clTectivcncss of Petzoldt’s afterword.⁷* As it turned out, Ludwig Mach waited until Joseph Pctzoldts dcath in 1929 and then rcmoved the pro-Einstein afterword and inserted his own anti-Einstcin foreword to the 1933 cdition of his father‘s Science of Mec hanie s.

During the carly ycars after thc war, Pctzoldt and Ludwig Mach kept up an cxtcmivc corrcspondcncc. The following cxccrpts from two letters by Ludwig Mach rcflcct his attempt to persuade thc Berlin professor that Ernst Mach ncvcr acccpted Einstcin’s theory of rela-tivity. The sccond cxccrpt is from thc finał letter bctwcen the two men and was dated June 4, 1923.

I can only rcpcat once again, my father was not a relativist as that term is currently understood.⁷⁹

[f you want to provc out of my 1914 corrcspondcncc Ernst Mach’s short-comings at that time, so should you already know today that I was spe-cifically ordered to deny your visit becausc of his perslstently painful bodily condition.

Rcgrcttably, howcver, in thc interest of truth, I must tell you today, that his fundamenta! reason was so as not to havc to talk to you about relatmty any morę.

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Albert Einstein and Hans Reichenbach rcactcd to thc hostile preface to Machs Optics by blaming it on his age and presumed intcllcctual senility, as if he had become too old to changc his mind. They also were inclined to thc view that a young Ernst Mach would have ac-ccptcd the theory of relatmty.⁸⁰ Hugo Dinglcr, howcver, thought otherwise.

The same man who rcjccted the theory of relatmty, wrote his Physical Optics, wrote Cultttrc and Mcchanics, and wrote a wholc series of popular articlcs. They were all written entircly by thc old Ernst Mach himself. Thcrc is not the slightest sign of any diminution in his mcntal powers. His extensive corrcspondrnrr and thr testimony of those around him also eon-firm this point. . . . Reichenbach thinks that thc young Mach without doubt would havc bccn a convinccd friend of thc theory of relatmty. Naturally, one has no absolute proof of such things, neither for nor against. But I think I am ablc to say from my knowledgc of Mach, that at that time he would already have taken the position which hr held latcr.⁸¹

Ernst Mach rcjccted the atomie theory and thc usc of multidimcn-sions in physics during thc i86os.⁸² Dinglcr was probably right in that Mach would have had to havc been at least in his middle twenties or younger in order to havc been favorably disposcd toward Einstein’s theory at first glance. Whether he could havc overcomc an initial dis-tastc for it during his earlicr ycars is of course something which cannot be determined with accuracy.

If Joseph Pctzoldt found a Tartar in Ludwig Mach. he soon dis-covcrcd an ccjually implacable foe on his other flank as well, namcly, Albert Einstein. The latter was adamant in refusing to accept Petzoldts "relauvistic" interpretation of thc constancy of the velocity of light. Pctzoldt argucd and argucd, bul Einstein would not givc in.

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