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Ernst Mach

pearances, and we nevcr perccivc anything but encrgy, or rathcr, dif fercnces in encrgy. “Wc never pcrccivc a materiał substancc itsclf, but only its energetie intcraction with our own organism.” ⁰ Mach defincd a "hypothesis” as any infercnce bcyond the appear-ances, but Ostwald attempted to reconcilc this definition with Macb’s belief in the inępmpletencss of science by stressing that in order t₀ penctrate into ncw arcas of knowlcdge it was ncccssary to start by making provisional assumptions or hypothescs of a sccond sort. I_n Ostwalda own words: “I distinguish hypothescs as arbitrary [“meta-physical”] assumptions, which one cannot prove, from prototheses as provi$ional assumptions, which one makes for the purposc of being able to establish proofs in prcviously unknown ficlds.” ⁷ Ostwald’s distinction betwcen two typcs of hypothescs has fitted in well with contcmporary vicws of our own day and has helped to bury Ncwton’s (and Mach’s) mislcading claim that they “make no hypothescs.”

Mach’s own reaction to Ostwald’s “Energeticism” did not fully satisfy the Leipzig professor. Mach claimed: “The fundamcntals of a generał energeticism were vcry briefly included in my 1872 book \Conscrva-tion of Energy], and hardly difTcred from Ostwald’s at all cxcept for his choscn Iabcl.”⁸ Ostwald, howcvcr, was vcry suspicious of Mach’s claim of oirtnal agreement. “He Mach] was one of the first to recog-nize and promote the generał significance of the laws of cnergy, but he would Jiot associate himsclf with Energeticism.”⁰ “Very character-istically Mach introduccs this fhis “antimetaphysical^M tcndency] into his attitude toward Energeticism. which he has not explicitly rcjectcd, but towards which hc is much morc critical than sympathetic.” ¹⁰ In spite of Mach's claims to priority and occasional support, Ostwalda doubts were well grounded. Mach necdcd Ostwald as an ally against atomism, but basically, Mach opposcd both “Atomism” and “Energeticism.”

Ostwald bclievcd in Energeticism as an cxplanatory theory to dc-scribc the appcaranccs and in cnergy as a reality. Mach as an onto-logical phenomenalist denied the reality of cwcrything that could not be a sensation, and hcld that all theories whether “atomistic,” “cncrget-ical,^H or whatever were mcrcly historical stages, of at best provisional value, v/hich science might pass rhrough on its way to the end goal of scicntific simplicity in the form of mathcmatical functions. On the basis of rhe availablc rvidcncc if serms, contrary to what ono might cx-

pcct and contrary to what somc of his followcrs sccm to havc takcn for grantcd, that Mach prcfcrrcd some varictics of atomie theory to encrgctical theory in making provisional cxplanations in physics.¹¹ But in the larger context this “prcfcrence” meant virtually nothing. In gist, Mach opposcd both atomism and energeticism on two counts: first, with rcspcct to their allegc'J ńćććssity“as śćićntific theories; and sccond, with rcspcct to the reality of atoms and cnergy as referents outsidc the appcarances.

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Heinrich Hertz (*857-1894) was born in Hamburg, the son of a lawyer and senator of the old Hanseatic scaport. He studied enginccr-ing, and later, turned to physics under Hclmholtz in Berlin. He sub-scquently tąught at Kieł (1883), Karlsruhe (1885), and Bonn (1889). Hertz becamc famous during the late i88os for his cxperimcntal dem-onstration of the existencc of clectromagnctic wavcs.

According to Hcrtz’s diary he first read Mach’s Mechanics on March 4, 1884.^1:1 Ten ycars later, shortly beforc his premature death, Hertz finished an influcntial book describing altcrnative approachcs to phys-ical theory, couchcd within Kant’s cpistcmology and Mach’s philos-ophy of science.¹³ In Mach’s own words: “[Hertz’s idcas] coincidc as cxactly as is possible with my own, considering that Hertz was a sup-porter of the mcchanical and atomie physics and a follower of Kant."¹⁴

The most important consequence of Hertz’s book was to impress physicists with allcged differcnces betwcen “dassicaT and "modern" physics. The cxpressions thcmscWes were appirently not uscd by flertz himsclf, but Poincare in 1897 and Boltzmann in 1899 uscd them in referring to 1 Icrtz’s book, thereby hclping to popularize both the distinction and the labels.¹⁵ What is cspecially to be noted is that the terms were in use before the discoveries of both Planck and Einstein, that is, beforc the discovcries that are currcntly supposcd to lu\c causcd and justified the distinction and labels in the first place! The most rcasonablc cxplanation would bc that Hertz notieed difficultics in Newtonian mcchanics and anticipatcd major cxpcrimental and the-orctical discovcries. Ncverthcless, the significancc of his distinction was that he based “modern physics” largely on Mach*s philosophy of science so that when the genuine modern physics of Planck and Einstein appeared, the new results bccame understood to a major c.uent

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