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Prcfacc

Mach. thc sevcnty-year-old scicntist-philośopher launchcd an unbclicv* ablc countcrofTcnsivc which includcd a host of articlcs and books, all typed witli only one finger of bis left band.

Spacc limit3tions havc foreed mc to omii scvcral of thc controvcrsics, including Edmund HussciTs rather one-sided attacks, but I havc tried to detail his wars with thc leading physicist of thc dny, Max Planck, thc most prominent psychologists of thc timc. Carl Stumpf and Oswald Kiilpc, and with thc subscquently famous revo!utionary Vladimir Lenin. Mach becamc embattled on all fronts, and even an early ally, Albert Einstein, gradually turncd against him.

Mach had always supported his own philosophical “theory of rcla-tivity,” but under thc drumfirc of constant criticism at the vcry end of his days Mach flatly rejccted both thc atomie theory and Einstcins physical theory of rclntivity as "dogmatic.” Machs followcrs, howcvcr, refused to bclicve his own words, and sińce his dcath in 1916 they havc uscd one argument or testimony after another to persuade thcmsclves that Mach “really” acceptcd atomism and physical rclativity. Arc their arguments legitimate? Havc they provcd their case? If this book can help provide the answer I will be morę than satisfied.

Far from scientific and philosophical disputes lay an idyllic world of peacc and “the generał public.” For most people “Mach” mcans “Mach-I” or “Mach-II"—exprcssions that bccame popular in the 1940$ when airplanes first broke the sound barrier. Ernst Mach’s most im-portant contribution to experimental physics was his work on shock waves and his photographs depicting bullcts breaking thc sound barrier. As with so much of his other work, this investigation took place many dccades before thc results were givcn extensivc attention. Mach first successfully photographed shock waves in 1886. In vicw of his importancc in thc field it is only appropriate that his namc has bcen applicd to so many different aspects of acronautics and gas dynamics: for examplc, “Mach number,” “Mach angle,” “Mach efTect,” “Mach reflcction,” “Mach stem.”

On the other hand. it would be fitting if Ernst Mach thc man werc eventually to bccomc better known. Ernst Mach, the philosopher of science, along with most of his controvcrsial idcas, is still very much with us, and thc timc for his comparative anonymity to disappear is long past due.

To clarify and occasionally criticize Mach’s philosophical ideas es-pecially thosc of a phenomenalistie or Buddhistic drift, I have often

contrastcd his point of vicw with what I cali “common scnsc." I mcan the rcprcscntationalist vicws of Galileo, Boyle, Lockc, and Newton— idcas widcly acccpted and used by practical pcoplc today and thc only cpistcmology compatiblc with a rcasonablc undcrstanding of thc proccss of perccption as acccpted by most scicntists in the field. 1 do not mcan by "common scnsc” cithcr the "Scottish rcalism" of Thomas Rcid and his allics or G. E. Moorc’s so-callcd common-scnsc philosophy and least of all contemporary “linguistic analysis” or "ordinary language philoso-phy.” Nor do 1 ecjuatc common scnsc with “na'ive rcalism.” The lattcr is primarily presentationalist in cpistcmology, that is, it identifies thc physical world with sensory objeets, while Galilean common sense, which is what I mcan. is rcprcscntationalist in that it assumes thc validity of the reprcsentative or causal theory of perccption and identifies the physical world with causal objeets and agents that exisi outsidc all conscious and sensory objeets or impressions. It is from this seven-tccnch-ccntury and practical approach that most of my criticisms are madę.

Followers of Berkeley, Hunie, and Kant along with morę recent pre-scntationalists such as Mach and Rudolf Carnap havc tended to mis-understand rcprcscntationalist or “common sense” philosophy as if it wcrc presentationalist and merely uscd a pcculiar linguistic approach. To understand rcprcscntationalist philosophy it is neccssary to assumc. contrary to Rudolf Carnap, that refercncc does not imply the cxistence of what is being referred to in any way, shape, or form. Galilean “common sense” philosophy, unlikc modern presentationalism, assumes that refcrence is an intentional act of allowance and is neither a form of cognition nor in any way subordinate to cognition. In other words, representationalist philosophy, properly understood, is not merely an-other “language gamę” but offers a genuinely different cpistemological approach, and liencc bas valuc as a foil with which to compare and better understand thc idcas of presentationalist philosophers such as Ernst Mach.

Major limitations in this book inelude insufficicnt coserage of Mach as a historian of science and of his influence on vcry recent work in philosophy and science. My cxcusc is partly the technical naturę of many of these problems, partly space considerations, and partly a de-sire not to criticize living philosophers. A second limitation concerns my vcry sketchy treatment of the “Mach principlc." In astronoms it