IMG86

Appendit

porarily persuaded.¹' A third explanation would be to identify Mach‘s rcaction wilh that of his ally and followcr Joseph Pctzoldt. The latter managcd to rctain his phcnomcnalism and yct acccpt thc rcality of atoms by rcdcfining "atoms" as ^ł‘complexcs of microscnsations.” ¹³ Hut if Mach agrccd with Pctzoldt, how are we to cxplain thc abovc quota-tions explicitly directcd against thc rcality of atoms in any form, cx-cept as ideas? The best answcr would bc that we cannot explain thcm in tcrms of PetzoldPs solution at all. lndccd, there is cvcry evidence from Mach’s publishcd works that few if any of his followcrs properly understood Mach’$ position on thc rcality of atoms.

If wc go directly to Machs Analysis of Sensations which hc per-sonally checked and rcvised in 1912, wc read: "If ordinary ‘matter’ must be regardcd mcrely as a highly natural, unconsciously constructed mental symbol for a relatively stablc complex of scnsational elemcnts, much morc must tliis bc thc casc willi thc ariificial hypothctical atoms and moleculcs of physics and chcmistry.” ¹⁴

Both thc spinthariscopc cpisodc and Mach’s stand on thc naturę and rcality of atoms should now bc elear. The spinthariscopc episode did occur and Mach was shocked, shocked by the existcncc of extrcmcly minutc microscnsations as represented in magnified form on a screcn, and hf mny have briefly ralled thosc sensations "atoms” before reflcct-ing on their actual charactcr. The microscnsations cxistcd, but they were not "atoms," first, bccausc all “materiał objeets” including “atoms” were mercly "mental symbols” for groups of sensations, and second and most important, becausc "atoms” as they were understood in physics could only bc propcrly understood in a spacc of morc than three dimensions, but thc space of sensations, including microsensa-tions, was only three-dimensional and could r.cver bc morc than three-dimensional.¹⁶

Mach had hcld this position on the rcality of atoms from thc early i86os, and thc spinthariscopc cpisodc did not change it at all.¹⁶ The only change was that Mach now acceptcd the cxistcnce of extrcmcly smali complcxes of microscnsations. which $ome~phcnomcnalists such as Joseph Pctzoldt and Anton Lampa, but not Mach, identified with y "atoms.” One may add that Machs position on the nced to under-stand “atorns” in a spacc of morc than three dimensions anticipated aspects of rccent quantum theory as has already been discusscd in chaptcr 19.

Did Mach finally acccpt thc rcality of atoms? No, hc did not! Atoms

rcquired a spacc of morc than three dimensions for satisfactory ex-plnnntion, but thc rcal world, that is, thc world of sensations, could nevcr havc morc than three dimensions, hcncc, atoms were unrcal.

Mach thc phenomenalist and ally of David Hume doomed thc understanding of Mach thc scientist. Mach’s form of phenomenalism was not compatiblc with belief in the rcality of atoms.

Pi