IMG�8

Ernst Mach

| speech with a fcw comments in the 1909 German edition of his Con-servation of Energy. Aftcr Planck published his address Mach camc back with a hefty articlc which both clarified his philosophy and at-tempted 10 answer P]anck’s criticisms. Mach^łs articlc “The Lcading Thoughts of My Scicntific Theory of Knowledgc and Their Rcception by My Contciiiporarics” (igio) was by far the most carefully argucd and pithy presentation of Mach's philosophy of science and has dc^ scrvcd to survivc its jeputation as a merę polcmical docutncnt.

Mach was amuscd by two aspeets of Planck’s philosophy: his un-critical faith in the absolutc vaiidity of a futurę, constant “world pic-turc," and his curious dcfinition of "rcality” as eon stancy. Mach, as a philosophical “relativist,” did not bclicve in absolutes ór constancics if that meant they were independent of sensations. Furthermorc, if atomie or moleeular particlcs changcd in space and time, then they were not "rcal" in Planck’s sense. Planck, himself, saw the problem, howcver, and rcactcd by attributing an unknowable Kantian “nou-mcnal” cxistcnce to atoms, a “solution” which a presentationalist likc Mach could only take cvcn less seriously. Herc arc sonie of Mach's morę irrevcrcnt comments on Planck as a philosopher and theologian of physics:

The conccrn for a physics valid for all times and pcoplcs cvcn for the inhabitants of Mars, whilc there arr still quitc pressing evcryday physical problems, seems vcry premature, indeed almost comical.⁷¹

If Planck had endcd his lccturc with page 32, there would havc bccn no rcason for mc to conccrn mysclf with it. But at this point hc starts his polcmic which is espccially dircctcd at mc. ... In particular his polcmical last rcmarks, their unusual form, complctc ignorancc of the matters in disputc, and their highly singular ccnclusion havc compcllcd mc to utter a fcw words in rcply.⁷²

rhc esscntial diffcrencc bctwccn us conccrns belief in the rcality of atoms.

. . Planck admonishes . . . with Christian mildncss, but finally brands mc with the wcll-known Bibie phrasc as a falsc prophet. One sccs, that physicists arc on the best way to becoming a church. . . . My answer is simple: If belief in the rcality of atoms is so crucial, then I rcnouncc the physical way of thinking, I will not be a profcssional physicist, and I hand back my scicntific reputation. In short, thank you so much for rhc coin-munity of beliesers, but for me freedom of thought comcs first.⁷³

In retrospcct, one should probably admirc the analogy imagiucd by Stephen Brush: “Mach givcs the impressior. of bcing a sinner on his dcathbcd, refusing to be convcrtcd by Father Planck to the faith which

21Ą

Mach vs. Bollznumn, Pianej, Stumpf, and Kulpę

nil of his collcagucs have acccpted. . . The troublc wiih ihis picture, howcvcr, is ihat it ignores the terrible naturę of Planck's second atuck which little rcflccted cirher a desire to persuade Mach out of error or to savc his soul in either a literał or figurativc sensc.⁷* Max Planck was dccply offended by Machs condcsccnding humor and contemptuous treatment of his ideas. As a rcsult, hc wrote a second articlc devoted cntircly to criricizing Mach’s philosophical and scicntific ideas in such a way as to forcc Mach into recognizing and respcciing the typc of person he was dcaling with. Planck aimed to break Mach. The articlc was titled: “On Mach’s Theory of Physical Knowlcdge—A Rcply" and appeared in1910. Herc are somc ąuotations:

Whilc my ideas havc found a ccrtain interest and occasional agreement from profcssionnl reprr$cntatives of transccndental philosophy they havc c.\pcricnccd, as might havc bccn cxpcctcd, a morc or less sharp rcjcction from followers of Machs orientation.

Until rcccntly I had no intention of returning to these matters. . . . Mach not only claims that his epistemology stands unrefuted, but hc is not scrious with my objcctions and evcn thinks I am entirely incapable of contributing anylhing to the epistemology of physics.

Since Mach, strangely, seems unablc 10 find a stronger opponent ... 1 fccl obliged to represent my objcctions to Mach's theory of knowlcdge somewhat morc clcarly than bcforc. . . .⁷⁵

[Mach] confuscs perpetuum mobile of the first typc (production of work from nothing) with perpetuum mobile of the second typc (uncompcnsatcd production of work from heat).^7tJ

Conccrning absolutc zero Mach rcmarks: “One has assumed that it is inconceivable to cool a body under —273 C., and that such a body contains no beat. I belicve, howcver, that this conclusion rests on an inadmissibly bold cxtrapolation.” Alas, one can as little compcl as forbid iKlicf in a scientific law.⁷⁷

Let us now consider Machs tenaciously fouglu for but physically uscless notion that the relativity of circular motion corresponds to the rclamity of translation motion, that one cannot decidc in principle whether the fixed stars rotatc around the earth at rest, or whether the carth rotates around the fixcd stars at rest. . . . To depict morc closely the physical conceptual errors which this inadmissible transfer of the law of the relativity of rotary motion from kincmaiics into dynamics has alrcady caused would carrv us too far aficld.⁷⁸

Up to now Mach's “fruits” havc not bccn woith much. But perhaps in the futurę? I am ready at any time to be taught better by the facts. Mach doubts that the second law [of thermodynamies ] can be carried through on

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