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Ernst Mach

forerunner of rclaiivity. I am ablc cvcn now to picturc approximately what ncw cxpositions and intcrprctations many of thc idcas cxprcssed in my bcok on mcchanics will rcccivc in thc futurc froin this point of vicw. ... I must, ho\vcvcr, as assurcdly disdaim to bc a forerunner of thc rc!ativists as I per-sonally rcjcct thc atomistic doctrinc of thc presentday school or church. The rcason why, and thc extcni to which, I rcpcct thc present day rclativity theory, which I ftnd to bc growing morc and morę doginatical, together willi thc particular rcasons which havc led me to such a vicw—considera-tions bascd on thc physiology of thc senses, cpistemological doubts, and abovc all thc insight resulting from rny cxpcrimcms—must rcmain to bc treated in thc scqucl. . . .^4B

Einstein soon rccovcrcd from the psychological blow of Mach’s flat opposition,lnit his own published commcnts took on a vcry mixcd tonę:

Mach was a gcod cxpcrimcntal physicist but a miserable philosophcr.*⁸

Mach’s system studics thc cxisting rclations betwcen data of cxpcncńce; for Mach, science is thc totality of thesc rclations. That point of vicw is wrong, and in fact, what Mach has donc is to make a catalog not a system.⁴⁷

According to my belief, thc greatest achievcment of Newton s mcchanics lics in thc tact that its consistcnt application lias led beyond this phenomc-nological representation (of John St. Mili and E. Mach).⁴⁸

In generał your [Moritz Schlick's] presentation fails to corrcspond to my conccptual style insofar as I find your whole orientation so to speak too positivistic. ... I tell you straight out: Physics is thc attempt at thc conccptual consiruction of a model of the rcal worid and of its lawful structurc. You will bc astonished about thc "metaphysicist” Einstein. Hut every four-and two-leggcd animal is dc facto in this sense metaphysicist.⁴⁰

Einstein began to sec thc light around 1917 and Mach’s 1913 prcfacc, which was published in 1921, madę the philosophical difTcrcnccs con-spicuous to evcrypnc; noncthelcss, thc fact rcmains that Mach had no-tieed thc incompatibility well bcforc Einstein. Epistcmological rclativitv and physical rclativity had nothing but thc merę word in common. In spite of Einstein's considerable debt to Mach, Einstein was neither Mach's philosophical nor scicntiftc “succcssor,” nor, as Einstein himsclf increasingly realized, was Ein$tcin's theory of relativity “positivistic” or cvcn compatible with positivism.^r,°

“Positivistic” rclativity insisted that “all sensations were dependent on all other sensations," but Einstein argucd that thc velocity of light in a vacuum was independent of other phenornena, that physical phc-

nomcna should not bc idcntificd with sensations, and that physical laws wcrc not mcrc “cconomical dcscriptions of the nppearanccs,” but had a constant validity independent of all sensations and conscious data. In other words, Mach’s cpistemological theory of rclativity and Einstein’s physical theory of rclativity were dissimilar to thc point of contradicting cach other such that no rational person could or should hołd both.

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