234 Fritz Weber

(Vienna, 1942.), pp. 58-9; W. Stresemann, The Berlin Phlharmonic (rom Blow to Karajan (Berln, 1979), pp. 61-2..

H Herzfeld, Magie, pp. 76-9; Musikgeschichte, pp. 602.-3. 34 Cf. F.-P. Korhes, Die theatralsche Revue in Berln und Wen I900-I9J8 (Wilhelms-

haven, 1977). 35 Concerning che ongins of che Musical cf. Schmidt-Joos, Musical, pp. 33-41. 36 Musikgeschichte, pp. 2.52.-6. There were a lso other conremporary sound repro-

duction systems like rhe Welre-Mignon and the Phonola processes, which enabled che direcr recording of p iano playing on paper ro lis.

37 Casals, Licht, p. 8. 38 Schivelbusch, Lichtblicke, pp. 87-109. 39 Quored in G. Salmen, Musiker im Portrat 5 Das 20. ]ahrhundert (Munich, 1984),

p. 150. 40 Quoted in H. C. Schonberg, Die grossen Komponisten (Berln, 1986), p. 507. 41 Quoted in Niemann, Musik , p. 2.70. 42. Cf. P. Gradenwirz, Musik zwischen Orient und Okdent (Wilhelmshaven and

Hamburg, 1977), pp. 32.4-5, 331. 43 Quored in Sirp, Dvork, p. 108. 44 Cf. Gradenwirz, Orient, pp. 2.2-6, 2.8 r-7. David also composed operas su eh as The

Pearl o( Brasil and Lalla-Roukh. 45 Ahlers-Hestermann, Stilwende, pp. 2.3, 31- 3, 74, 84; Friedell, Kulturgeschichte,

p. 1333 46 Cf. W. Schivelbusch, Das Paradies, der Geschmack und die Vernun(t . Eine

Geschichte der Genussmittel (Frankfurr-on-Main, Berln and Vienna, 1985), pp. 215-26.

47 Following Frederico Larca, quoted in Gradenwitz, Orient, pp. 33o-4. 48 K. Linke, 'Zur Einfhrung', in Arnold Schonberg (Munich, 1912.), pp. 13-2.1. 49 Similar reflections should be enrertained concerning Shostakovich's ' heroic '

symphonies, composed befare he was criricized by Stalin and Shdanov. For the history of orchesrration in general cf. H. Raynor, The Orchestra (New York and London, 1978); A. Carse, The History o( Orchestration (New York, 1964).

so Cf. l. F. Belsa, Alexander Nikolajewitsch Skrjabin (Berln, 1986), pp. 198-2II; R. U. Ringger, Von Debussy bis Henze (Munich, 1986), pp. 26-7.

51 Quoted in P. Werckner, Aufbruch in die Moderne, in Das Zeitalter Kaiser Franz ]osephs (Vienna, 1987), p. 2.27.

52. Quoted in P. Stefan, Gustav Mahler (Munich, 1912), p. 83. 53 Quoted in Musikgeschichte, p. 576. 54 Quoted in A. janik and S. Toulmin, Wittgenstein's Vienna (New York, 1973),

p. IOI. 55 Stuckenschmidr, Neue Musik, pp. 82.-3.

tt .

1

TWELVE

;-.;..; ~

THE TRANSFORMATIO N OF PHYSICS

ER WIN N. H!EBE.K. T

REF LECT I ONS ON T HE PH YSI C S DISCIPLINE

The end of the nineteenth century has been characterized by numerous authors as a time of intellectual and artistic decadence, political calumny, social discontent and widespread, general dissonance. By contrast it is universally asserted that advances in experimental and theoretical physics at the turn of the century set the stage for the revolution in physics that followed. lt has become commonplace to view fin-de-siecle changes as a watershed separating the old physics from the new. In this context we will be referring to ' the transformation of physics' that took place in going from 'classical physics' to the 'new physics' of the twentieth century.

Unforeseen and abrupt as this transformation seems to have been, especially when examined with the a id of hindsight, it neverrheless can be said that most if not all of the decisive anchor points of the 'new physics' can be linked with components embedded in late nineteenth-century classical theory and practice. There were many contextua] factors that made the 'new physics' possible. The establishment of research institutes and laboratories and the increased accessibility of scientific instruments were concurrent with the overhauling of methods of university instruction and laboratory practice. There was a gradual shift towards collaborative research that would have been beyond the reach of individuals. Above al! the transformation of physics was facilitated by the birth of an expanding international consensus concern-ing the positive value of the natural sciences.

While the emphasis in this paper will fall on the discipline of physics itself, we recognize that the turn of the century also can be represented as a time when access to technological progress and mass participation in communica-tion, transportation, domestic illumination, plumbing and central heating-that had been reserved for a privileged class - began to be extended to the

236 Erwin N. Hiebert

public. Such changes run parallel wirh the development of physics; frequemly experiment was ahead of theory, and somerimes technology was ahead of borh. Evidence for rhe genuine and brisk transformation of physics rhat began in 1895 is exhibited most of all in the way that the experimental and rheoretical subject matter of physics changed. The practice of doing physics was modified simulraneously wirh a restructuring of rhe professionalization of rhe discipline.'

The spomaneous and largely unanticipated disclosure of entirely new domains in physics and chemistry at the end of the century, such as X-rays, radioa_:tivity, quantum rheory and rela tivity, served ro accenruate rhe differences in outlook thar often were and still are alluded to in contrasting the progressive character of rhe natural sciences and the image of rhe so-called fin-de-siecle stalemate in social and polirical practice. Sorne of the expressions that carne into vogue with fin-de-siecle reflections on the world of culture are: bourgeois decadence, imellectual bankruptcy, irrational escapism, freedom on rhe fringe of bored aestheticism, the abyss of freedom, fashionable despair, cultiva red fatigue, and collapse. 2

None of the negative expressions rhat have come to be associated wirh turn-of-rhe-cemury perspect ives on literature, society, and the fine arts properly capture rhe state of affairs and intellectual climate in physics between r88o and 1910. Neverrheless, iris pertinem to indicare at this point, but without entering into specifics, that the perceived upswing turn-of-the-century mood in physics by no means was thought by contemporaries ro be the sole prerogative of the natural sciences. In fact there were many writers and artists who championed the dawn of a new da y that, rhrough relea se from rhe burdens of the pasr, would make available unimagined new literary and artisric possibilities. A vortex of unprecedented freedom, creativiry and sensibility had been aroused, unloosed and ser free. In music, for example, various musicologists, histo rians, composers and music critics have given positive appraisals for the period.

Before proceeding with an analysis of rhe preconditions and transforma-tions that characterized turn-of-thc-century physics, it is pertinent to specify what was meant by 'physics' at the time. To physics in the r89os belonged ' the science or group of sciences, basically treating of the properties of matter and cnergy'.3 In reference ro domains or sub-disciplines within physics, this would ha ve included, foremost, the study of matter in motion under the influence of forces, i.e. mechanics, but also rhermal studies and thermodynamics, physical and geometrical optics, and the electromagnetic theory of radiation. The term 'classical physics' was not in widespread use until the 192os.lt was imroduced to distinguish the ' new physics' from 'conclusions based on concepts and theories established befo re the discovery of quantum theory or relativity, etc.'.

THE TRANSFORMATION OF PH YS ICS 237

A concise and exemplary statemem of what actually happened in physics rhat would bring the expression 'classical physics' into prominence, is given by Paul Dirac in 1930:

T he classical tradition has been to consider the world to be an association of observable objects (particles, fluids, etc.) moving about according ro definite laws of force, so rhat one could form a mental picture in space and rime of the whole scheme. T his led to a physics whose aim was to make assumprions about rhe mechanism and forces connecring these observable objecrs, ro accoum for rheir behaviour in the simplest possible way. lt has become increasingly evident in recent times, however, rhar nature works on a differenr plan. Her fun damenrallaws do not govern rhe world as ir appea rs in our mental picrure in any very direcr way, but insread rhey control a substratum of which we cannor fo rm a mental picrure wirhour imroducing irrelevan-cies. The formularion of rhese laws requires rhe use of rhe marhematics of rransforma-rions. The imporranr th ings in rhe world appear as rhe invarianrs (or more generally rhe nearly invariams, o r quantities wirh simple transformarion properties) of these transfo rmarions. The things we are immediately aware of are the relarions of rhese ncarly invarianrs ro a cerrain frame of reference, usually one chosen so as ro introduce spccial simplifying features which are unimportant from rhe point of view of general theory.s

It is evidem from Dirac's sraremem that theoretica l and marhemarical physics would be given pride of place in the 'new physics' that carne to be builr around relativity theory and quamum theory. In these newly generated domains the reciprocity between experiment and theory was seen ro be largely dominated by rheories that are grandiose in claim and powerful in rhe suggestion of experimenrs that support the theory. The models for such majestic and commanding theories were inherited from rhe nineteemh century.

A retrospective examination of rhe most impressive rheoreticallandmarks in physics by the end of the nineteenrh century revea ls rhat three domains of 'classical physics'- mechanics, thermodynamics and elecrromagnetic theory - stand out conspicuously by virtue of the far-reaching consequences that can be drawn from a set of concise principies. These principies, in turn, can be derived from a surprisingly small number of axiomaric premises and pheno-menological observations. By the end of the century considerable effort had been devored ro achieving sorne kind of deep-level integrat ion of these three domains but without overa ll success. Enthusiasm for theoretical unification gave way ro phenomenological expansiveness where novel discoveries did not fit into any of rhe known theoretical niches: X-rays in 1895, natural radioactivity in 1896, ident ification of the electron as a particle of discrete mass and charge in r897, and by 19II evidence that the atom was roo,ooo times the size of its nucleus. Conceptually too, physicists were compelled to come ro terms with quamized energy notions (1900), the relarivity of space, time and motion (1905), and an internally structured atom where classical

238 Erwin N. Hiebert

mechanics collapsed. Study of properties and processes for che atomic nucleus - for which there was no preceden e, noc even in chemistry or quantum theory - opened up new worlds chat were inconceivably complex.

FRONTIERS OF PHYSICS

The transformation of physics was realized simultaneously at the frontiers of experimental, theoretical and mathematical physics. This division of scien-tific labour essentially had been put in place professionally during che last three decades of che nineteenth century. Prior ro that time there basically were just 'physicists' whose expertise was dominant in one or more of che three areas. A few remarks will serve to clarify how physicists at the turn of the century sought to gain access to and integrare experimental, theoretical and mathematical physics.

The history of experimental physics, or at least what later generations referred to as experimental physics, can be traced over severa! centuries. The growrh of physics and che recognition of its social value, notably after r87o, brought new significance ro che role of experimentation and invention, its industrial patronage and its professional institutionalization. During che last three dccades of the century che application of scientific principies, notably in che domain of electromagnetism, gave rise to an expansion in practica! inventions that would lead ro the perfection of tclegraphy, telephone, incandescent electric lamps, induction coils and dynamo-driven electric supply stations. lt therefore comes as no great surprise rosee that towards the end of the century university posts in experimental physics increasingly carne ro be established, principally, one might suggest, ro distinguish the pursuit of experiment as a speciality from mathematical and rheoretical physics, but also ro give such posts academic authority.

Machematical physics, prominent rhroughouc che nineteenth century, had been culcivated by both physicists and mathematicians who occupied chairs in mathematical physics, physics or mathemacics, or any combination of them. This assimilation of skills reflects the need and the structure of the professional discipline of physics through most o f its history . 1t also contri bu red substantially ro che setting of the stage for the establishment of positions in theoretical physics by the end of the cemury.

In 1875, for example, a sizeable number of British physicists, such as Stokes, William Thomson, Maxwell and T ait, exhbited extraordinary competence in mathematics. Coincident with the political unification of Germany in the r87os carne che movement ro reshape the institucional structure and training ideals in physics at the universties. Mathematics notably was given a new emphasis. Physcists like Helmholtz, Kirchhoff and

1 1

li

THE TRANSF O RMATION OF PHYSI CS 239

Hertz exhibiced mastery in mathematics but were equally at home with rheory and the experimental workshop. By r88o, in Germany, mathematical physics ca meto be looked u pon as a special doma in of physics. In France there was Cornu, and in America, Gibbs. A positive srimulus, chac served co cnhance the status and significance of both mathematical and theoretical physics, was provided by the rapid growth of invescigations made possible by che refinement and proliferation of scientific instruments .

There al so was a growing technical a wareness of che relevance of physics in industry at che internationallevel -a perspective that chemists had enjoyed for at least a century. William Thomson (Lord Kelvin) is a prime example of a physicisr who, in addition ro being one of the best mathematical physicists of his time, also was something of a technological entrepreneur; he commanded an in-depch knowledge of everything connected with electrical signalling, sensitive measuring devices, navigation, tides and waves.

The transformation of physics that is the focus of our concern here carne more and more to depend on the mathematics of machematicians, and especial! y on such as explicitly had extended their intereses to specific copies in physics. 6 The unreasonable, almost uncanny pertinence and poten e y of mathematics for physics, as seen in the crearion of relativity and quantum mechanics, became a much-discussed issue among physicists and epistemolo-gists. In these discussions attempts were made ro establish che onrological status of the formalisms that were generated. How was one ro cometo terms with formalisms - mathematically elegant and scientifically powerful - that wcre so effcctive in physics but so difficult to transpose into meaningful physical models- mcchanical, rhermodynamic or field rheoretic? The new physics, as Dirac commented, led to the loss of mental models. They were rcplaced by invariants that were chosen for their simpl ifying fcatures; they could be manipulated by mathematical transformations.

The crux of the matter was thar the mathematical formalisms worked. They accounted for known phenomena, predicted new ones and led to theories and conceptual framcworks that did the same. When explanatory success was accompanied by theoretical, conceptual or mathematical com-plexity, physicists, then as now, explored strategic moves that would lead closer ro a unitary physics. T o elucidare what was meant by unity , of course, was open to debate. In 1900, speaking to an internat ional audience in Pars, Henri Poincar expressed the view that what was needed was not so much an abstraer and general conception of the unity of nature, as a search for che sense in which nature might be conceived from a unitary point of view within thc context of the available resources in experimental and rheoretical physics.'

lt was not until the 187os that 'rheorerical physics' ca me ro be recognized as

240 Erwin N. Hiebert

an autonomous doma in within the physics discipline. E ven then the opportu-nities for a career anda university post were rather occasional. Physicists such as Einstein and Gibbs, who by choice were comparatively fa r removed from direct access to experimental activities, pursued on their own what can be designated as theoretica l physics. Others such as Bohr, Helmholtz, Larmor, Laue, Ritz and Wien were known primarily for their theoretical physics but srood in close contact with the experimental frontier. There were rclatively few academic chairs explicit!y established for theoretical physics, perhaps fewer than a dozen by 1905 - the date of publication of Einstein's special relativity theory. 8

In comparison with experimental physics, theoretical posts, early on, did not always carry great prestige. In fact, an argument can be made, at least for turn-of-the-century Germany, that the most lucrative and desired pro-fessional university posts in physics were reserved for experimentalists and not for theoreticians. This imbalance in the discipline, in my opinion, goes a long way towards explaining why persons who did not ha ve access to rhe best (i.e. experimental) positions in physics would have specialized in the more speculative and less traditional, i.e. theoretical , domains of physics. One might suggest, for example, that it was built righr into the German university system that Jewish physicists would be forced, reluctantly- at least from their point of view as job-holders- to take up eccentric and controversia! themes such as relativity, quantum theory and sorne aspects of nuclear physics. As it turned out, iris precisely in these new domains that the theoretical contribu-tions of Jewish physicists became prominent. 9

FJN-DE-SIECLE MENTALITY

From our comments thus far ir will have become evident that the transition from classical to twentieth-century physics took place in a relatively unbroken and tranquil but reformist and spirited manner. That is to say, the transformation of the physics discipline was realized within an intellectual and social environment - mosdy academia - that exhibited none of the stereotypical and demeaning referents that often, if not universally, carne to be associated with 'fin-de-siecle' mentality. How widely this polarization was thought to reach at the time depends on which authors, contemporary and later, are consulted. Even so a very prominent view is that the sciences everywhere were on the move while deterioration and retrogression were rampant in most non-science domains.

The most assertive expression of the uniquely progressive spirit in the physical sciences comes not from spokesmen within the physics community but from biologists and social scientists seeking ro buttress their own

fl

.' JI :~1

THE TRANSFORMATION OF PHYSICS 241

scientific prestige by endorsing and appropriating ro their own disciplines rhe most conspicuous accomplishments in physics. T he positive reinforcement that physics enjoyed within the small and privileged circle of scientists served to genera te within the minds of the general publica growing awareness of the importance of physics. This was accompanied by rising expectations concern-ing the potential social benefits of the technological by-products of physics.

The German electrophysiologist Emil Du Bois-Reymond stands out as one of the most domineering of nineteenth-century European scientists. He p]ayed an active role in promoting discussions on the connection between the natural sciences and the humanities. His research programme was based on developing an experimental science rhat would reduce physiological pro-cesses ro electrical, molecular and atomic mechanism drawn from physics. He rejected the idea of 'vital force' in physiology. It was for him a metaphysical notion that violares the principies of conservarion of energy. In his lectures of r87z and r88o he had brandished the expression ignoramus- ignorabimus (we do not know it- we never will know it) to characterize transcendental questions that are meaningless because scientifically unanswerable. 10 His polemical pronouncements gave rise ro a polarization among scientists and philosophers that became a vehicle for scientific critiques of what were seen ro be dogma tic and unreflective epistemologies of cognition. Within the context of debates on cultural, political and educacional policy, at the end of the century, anti-metaphysical materialists used the ignoramus-ignorabimus image as a flag of convenience to espouse the cause of the emancipation of science from orthodoxy in philosophy and theology. All were ostracized in one way or another for their heretical philosophical positions. They none rhe less enjoyed wide readership. 11

Du Bois-Reymond embraced a confidence in 'science that strides on victoriously towards a boundless future', where the scientist - as sworn witness 'befo re the tribunal of reality striving for knowledge of the universe as it actually is'- experiences a 'feeling of responsibility in presence of Nature's eternally inviolable laws' .12 In comparing the progressive character of late nineteenth-century natural science with the 'falling-off' and 'at best station-ary' condition of the arts, Du Bois-Reymond writes: 'No real civilization would exist without it [science], and in its absence nothing could prevent our civilization, including art and its master-works, from crumbling away again hopelessly as at the decline of the ancient world. ' 13 Du Bois-Reymond wanted the natural sciences to occupy a position of primacy above all other branches of learning and arts, beca use he believed that only science was able to provide the basis upon which the ancillary furniture of healthy civilizations could thrive. Although he had no sympathy with Goethe's views on nature and science he valued Goethe's nimble-witted command of language: 'Goethe

242 Erwin N. Hiebert

very truly observed -little thinking how harshly ... his remar k reflects on part of his own scientific work ... that: Nature allows no trifling; she is always sincere, always serious, always stern; she is always in the right, and the errors and mistakes are invariably ours.'' 4

Towards the end of the century one encounters growing public support for an image of science as friend and ally of rhe masses- a point of view that went hand-in-hand with sentiments deploring rhe degradaran of standards in the arts, literature, religion, politics and philosophy. In popular and polemic works, distributed far and wide, anti-metaphysical materialists, as we shall show, spread the gospel of an in-process transformation of science that would transcend the fin-de-s ii!Cie decadence taking place in those branches of learning having primarily a cultural characrer. For example, Karl Vogt, zoologist, geologist, marine biologist, champion of anthropological Darwin-ism and outspoken atheist, was skilled at cultivating the image of the scientist. Vogt was described as one who from time ro rime as the conscience of society 'steps out of rhe cal m of the laborarory inro the marker-place of life and feels himself called upon to let all mankind take parr in the spiritual blessings of scientific progress'. 15 Vogr hada gift for polemic and oratory. His materialist philosophy was laid clown in r853 in a caustic analysis of 'blind faith and belief' (Kohlerglaube und Wissenschaft) . The work, published in severa! editions, caused a great commotion that to rhe end of his life was kept alive in his physiologicalletters. These are replete with catchy phrases rhar often were quoted ro characrerize crass marerialism: 'The brain secretes thoughr as rhe kidney does urine', or 'thoughts are ro the brain as the gall is to the Ji ver or urine to the kidneys'.16

The mosr influenrial of the German materialists, Ludwig Bchner, carne ro fa me with a popular scientistic and moralistic exploitation of rhe principie of conservaran of energy, Force and Matter, a work first published in 1855 and in its eighteenth edition by the time of his death in r899. 17 Towards the end of his life Bchner published a mock-heroic trearise, At the Deathbed of the Century, in which the sready advancemenr and benefirs of rhe natural sciences were played off againsr rhe decadence exhibited in philosophy, religion, spirirualism, naruroparhy, polirics, anarchism, social quesrions, women's rights, rhe Jewish quesrion and lirerature. He writes:

One mighr assume rhat rhe splendid advances in the sciences should ha ve resulted in justas m u eh progress in the thinking and meaning of mankind concerning the aim and purpose of existence. Miraculously, exactly the oppositc is rhe case; this ranks among the many unclarified riddles and contradictions of world history. The greater the depth and compass of science on rhe one side, rhe grearer rhe reacrion against the conclusions thar could be drawn from science ... 18

THE TRANSFORMATION OF PHYSICS 2 43

In his Janus-faced portrait of the state of affairs at the century's end Bchner gave an enrhusiastic account of the splendid advances, d iscoveries and inventions in the natural sciences and especially in the physical sciences. 19 He also had kind things ro say about studies in hypnotism and the shift that had taken place when psychology broke its alignment with philosophy and moved rowards anthropology and psychiatry (Seelen lehre). By contrast Bchner saw that almost everything that falls beyond the boundaries of the natural sciences had deteriorated - had taken up parrnership with rhe most gloomy and hopeless sentimenrs of mankind. In fact, he believed that in the world of culture, despair would produce negative pressures upon the future advancement of the sciences. Philosophy, he believed, had deteriorated to preoccupation with 'speculative solutions for the last and highest rhings', and to metaphysical talk about 'deriving rhe rotality of being and thinking from an integra red all-encompassing principie that would salve the grear riddle of rhe u ni verse'. 20

Religion and the religious lie - spread by state, church, judge and the educated modern priest - were seen ro dominare the civilized world and had served to demoralize men's public and prvate lives. Spiritualism, as the retrograde movement of rhe mind (geis tiger Krebsgang), and belief in ghosts and spooks, had infecred millions. Politics withour wisdom was the arder of rhe day. Anarchism, wild and egoistic impulses, and antisocial instincts, were on the increase. The general esteem and standing of women had decreased from former rimes while rheir workload had increased. The florescence of anti-Semitism in the Kaiserreich was the disgrace of the century.11 Art and literature were sarurated with degeneraran and mental laziness that was sickening, rotten, damaging, weak, miserable, tasreless, sensacional, abnor-mal: 'Iris rhe time of so-called decadence or decay which seeks to cover up, in its personalities as well as in the form or representaran, its want of intellect and character in the depiction of extravagant, artificial, pathological feelings and si tu a rions.'zz

The riptide of enthusiasm for the pursuit of science, in thc midst of a perccived and, onc might add, fabricated fin-de-siecle degeneraran in morality, ethics, belicf systems, art and litera tu re, is nowhere more anxiously chased after than in the works of the zoologist Ernst Haeckel whose blending of monism, social Darwinism, pantheism and materialism seemingly ans-wered sorne contemporary needs of the day. His 'scienrific philosophy' was roored in an uncompromisingly monistic empiricism, nurtured by harsh criticism of church dogma. In The Riddle of the Universe (1899), a work which found immediate popular acclaim and achieved great success in many editions and languages, Haeckel wrote:

244 Erwin N. Hiebert

Ar rhe clase of rhe nincreenrh cenrury, befare which we stand, une uf rhe most remarkable specracles is offered ro rhc rhinking observer. All educa red persons are in agreemenr rhar in many respecrs this manifesrarion immeasurably oursrrips all uf irs predecessors and has led ro the solurion uf prublems thar werc insoluble ar firsr. Nor only the unexpecred rheoretical progress in genuine knowledge uf nature, bur also the amazingly fcrtile, practica! applications in tcchnology, industry, communicarion, and so un, ha ve given our modern culturallife a torally ncw special character. On the other hand, in important domains of intcllecruallifc and social relarions rhere is little or no progress ro show over previous cenruries, and unforrunarely often even serious retrogressions. From rhis evident conflict rhere ariscs nor only an uncomforrahle feeling of inner disintegrarion and untrurh, bur also the danger of carasrrophes in political and social spheres. J

TRANSFORMATION OF PHYSICS

We ha ve sought here to characterize the main fea tu res of the scientific scene as it was represemed in the reflections of scientists and self-christened, materia-list philosophers at the turn of the century. The euphoria about science that was dramatized in their writings coincided chronologically with the fin-de-siecle decadence that was judged by them to be seeping into all arcas of thought and action lying outside the province of science, i.e. those branches of learning regarded as having primarily a cultural character.

Physicists preserved a less sinister impression of the malaise of the time. On the one hand, they were less pessimistic about their surrounding non-scientific culture; or at least they were less outspoken about cultural degradation. On the other hand, physicists were not totally sanguine about the unbounded future of their own discipline. At most it was ro be hoped that the rich harvest of new scientific discoveries might provide a promising point of departure for a critica], naturalistic, scientific humanism whose main objective it would be to organize scientific knowledge on behalf of human welfare. From an interna] point of view, however i.e. from the standpoint of the physics discipline itself - the future, unlike pre-r895 physics, was unforeseeable, promising, uncharted.

During the last two decades of the nineteenth century, scientists had witnessed an expansive growth in the scope, content, practice and technologi-cal relevance of rhe natural sciences. In physics the maturity and refinement of theoretical principies was conspicuous, notably in continuum mechanics, thermodynamics and the electromagnetic theory of radiation. In the midst of these grand accomplishments, formidable phenomenological and theoretical difficulties, of course, were identified. In general, however, it was assumed that the elucidation of the most troublesome anomalies would depend less upon the discovery of new theoretical guidelines than upon successful

THE TRANSFORMATION OF PHYSICS 245

integration into the body of what later carne to be referred to as 'classical physics'. That is to say, the prevailing mood in physics was one that was oriented towards correlating newly discovered information wirh what already had been laid clown. This perccived lull in physics prior ro 1895 unquestionably was real. lt nevertheless has received undue emphasis in the hisrory of science, for with the benefit of hindsight it is tempting, and too easy, ro pinpoint and contrast the explosive changes in the complexion of physics rhat occurred betwcen the mid-r89os and 1905.

Not long after r89 5, physicists were forced to recognize that their discipline was potentially open-ended to fundamental novelry in both experiment and rheory. This mental switch, from seeming complacence to inquisitive expec-rarions, had been accentuated justa few years earlier by high-level assertions rhat the future of physics lay mostly in mopping-up operations and refine-ments in what was already known. While there can be li ttlc doubt about rhe steady forward march of experimental physics and practice during the last rwo decades of the century, on the whole, conspicuous rheoretical accom-plishments were infrequent. This gave rise to the general opinion that perhaps rhe more important physical fearures of nature airead y had been discovered, and rhat improvements in theory were to be looked for mainly in the details rather than elsewhere on new rheoretical frontiers.

The prominent physicist Gusrav Kirchhoff, whose forre was theory but who also placed great value on the essentiallong-range need for experiment, was convinced that there were but slim chances of upsetting or even fundamentally revising the main theoretical pillars of physics. Kirchhoff's comprehensive lectures on mathematical physics are a living symbol of self-contained unitary physics from a phenomenological point of view. 24 The self-confident message concerning the advanced status of theory in physics is mollified only by accentuating the limitless frontiers of experimental refine-ment in basic theory.

One of the most frequently cited passages ro illusrrate the closure of physics at the end of the nineteenth century is the onc made by Albert Michelson. In his Lowell lnstitute lectures of r899 he said:

The more important fundamental laws and facts of physical science have all been discovered, and these are now so firmly csrablished thar the possibiliry of their ever bcing supplantcd in conscquence of new discoveries is exceedingly remote ... Our fmure discoveries must be looked for in rhe sixrh place of decimals.15

This sentiment represents vintage Michelson, for it was in keeping with his lifclong passion to develop ever more precise optical equipment for the measurement of rhe speed of light - a task he carried out with six-figure precision. Michelson was not mere] y asserting that the discovery of laws and

246 Erwin N. Hiebert

facrs would taper off; he was suggesting that experiments would show the way to the future. In this he was not so far off the mark. lt was rather that he had too myopic a perspective on how radically experimental investgations might alter rhe theoretical structure of physics. ' lt follows that every means which facilitares accuracy in measurement is a possible factor in a future discovery, and this will, I trust, be sufficient excuse for bringing ro your notice the various methods and results which form the subject-matter of these lectures. '26

By the end of rhe first decade of the rwentieth century sixth decimal place physics was pass. The discovery of X-rays, natural radioactivity and the electron paved the way for the study and theoretical interpretation of radiation and spectra, atomic and molecular theory, quantum theory and relativity. In 1911 Rutherford and orhers put forth a nuclear theory of the ato m. In 1913 Nicls Bohr published his planetary theory o f the hydrogen atom hased on quantum considerations. After 1920 particle-induced transmuration of elements became well known.

Apart from the transformaran of physics associated with the enunciation of relativity theory, perhaps the most conspicuous fin-de-siecle watershed separating the 'classical physics' of r895 from the 'new physics' of 1905 penains ro rhe status of the corpuscular theory of matter. Throughout the nineteenth cemury the ato m, although discovered to be more or less ancillary ro the mainstream of physical theory, was conceived of as a mechanical entity subject to attractive forces and possessing properties such as mass, density, impenetrability, elasticity, mobility and extension. Atomism and mechanism carne to be so firmly held conceptually that most of the philosophical, physical and chemical debates surrounding the mechanistic interpretation of science spilled over into discussions about aromism, and vice versa.l7

Towards the end of the century, however, many physical scientists felr that the atomic-molecular-kinetic model o f matter was not deeply embedded in mechanics, thermodynamics, electrodynamics or structure of matter theory . lt was widely undersrood among scientists that there was no adequate description o r explanation of the physics and chemisrry of atomic pheno-mena. Parta] clues as ro where the solution might be found carne from a host of di verse puzzles generated from within physics and chemistry. 28

The fundamental significance of the corpuscular theory of matter for physics carne about only after the discovery of the electric atom (the electron), the planetary and nuclear models of the atom, the correlation of spectra with atomic structure, the quantum theory, the artificial transmutation of ele-ments, the particle nature of all forms of radiation, and the wave nature of particles. By 1910 it had become evident that the atom was a complex, structured, unstable, dynamic unir not at all similar to the ato m of lucretius, Gassendi, Newton, Dalton, Maxwell or Kelvin .

THE TRANSFORMATION OF PHYSICS 247

CONCLUDING REMARKS

Michelson's 'sixth decimal place physics', as a maxim fo r the calm in r899 rhat preceded the stormy first decade o f the twentieth century, fa lis short in providing substantive insight into the major trends and climate of opinion prcvalent among physicists at the time. Accordingly we offer an attempt ro reconstruct a number of the most prominent landmarks currcnt among members of the physics community around 1900, plus or minus five years.

In first place, a widcspread belief existed - perhaps bordering on wishful rhinking- that an expansive unity in 'classical' physical theory was feasible if not yet within reach . Iris tempting to view such monistic perspectives as pa rt and paree! of a larger doctrine of progress and the logical extension of nineteenth-century reductionist thought. By conrrast, late ninctccnth-century critica! positivists such as Mach, Duhem and Poincar maintained a brand o f radical pluralism that, although rooted in scientific monism, was a monism of scientific methodology and not of theory. In any case, between 1900 and 1905 considerable emphasis was givcn ro mastering the physics discipline in a unified way in order to encompass fundamental rcformulations in physics indicated by new discoveries. Physicists, it seemed, were on the verge of a rransformation of the discipline that, toa pre-eminent degree, would modify rhe thinking of scientists in all fields. Rightly or wrongly rhey fe!t that what was happening would revolutionize the whole doma in of physics more than all that had gone before.

The self-confident and brazen elitism concerning the march of pure physics was not the only determinant for the new optimism. In another place 1 ha ve rcferred ro concomitant advances in technology as a factor:

The future of electrical technology ... was seen ro be ver y promising, indeed, although we recognize that much of what was known ro be technicall y and economically fcasible was communicated ar the level of grand cxhihitions and public demon-srrations ... Reflections on rhe srare of science consritute a veritable hymn of praise for practica! progress in electrical engineering: morors and dynamos with shutrle-wound armatures, polyphase transmission, electric induction machinery, frequency rrans-formers, the telephone, the microphone, and wireless telegraphy. There is hardly a word about the use of combusrion engines for transporrarion, but the number of articles devoted ro the rosy future rhat was ahout ro be ushered in by electrical means of communicarion is impressive ro say rhe least.19

We ha ve a lready referred, in the above, to the crucial role thar was given to physics in the post-1895 discoveries associared wirh the corpuscular structure of matter. The complete switch of inrcrcst and confidcnce in structurc of matter investigations around 1900 is nowhere more conspicuously seen than in the sudden way in which physicists and chemists rerreated from their anri-a tomistic posirions. An examination of the unanticiparcd and spcctacula r

248 Erwin N. Hiebert

experimental discoveries made during these years serves to show how dense was the terrain on which investigators were compelled to construct a new physics based on the corpuscular theory of matter.

The correlation of gravitational theory with specrroscopy at the end of the century was critica) for the establishment of astrophysics as a major branch of physics. lt served to reinforce the essenrial uniqueness o f the atomic-molecular perspective throughout nature. Roben Woodward, Columbia University Professor of Mechanics and Mathematical Physics, wrote in 1904:

lt would be roo bold, perhaps, ro asserr rhat rhc:: trc::nd uf accumulating knowledge is roward an acomic unity of marrer, bur rhe da y seems nor far disranr when rhere will be room for a new Principia and for a trearise rhar will accomplish for molecular sysrems whar rhe Mchanique Cleste accomplished for rhe solar sysrem.30

In chemistry the atomic-molecular theory was, if anything, an even more sure-footed route towards understanding such fundamental issues as chemi-cal spontaneiry, equilibrium, structure and chemical kinetics. Physicisr Professor Woodward, mentioned abo ve, recognized this clearly when he said: 'If the progress of physics during rhe past century has been chiefly in the direction of atomic theory, che progress of chemistry has been more so. Chemistry is, in facr, the science of atoms and molecules par excellence.31

Various other trends are discernible in the physics communiry around 1900. One that merits special attention follows from the recognition that almost none of the new discoveries had been foreseen or predicted on the basis of established theoretical principies. This perception encouraged the taking of risks. Speculations about the unknown were made in hopes that emprica! findings sooner orla ter either would validare a new idea or el se be eliminared harmlessly from the record. The accent fell on the porentially posirive incentives of imaginative and interrogative assumptions thar might generare experimentally feasible and theoretically fertile consequences. The classical nineteenth-century categories of physics no longer were sacrosancr.

This generalization is not entirely warranted. 'Classical physics' never vanished from twentieth-century physics practice or textbooks. Many con-cepts and principies remained virrually unchallenged and, in fact, served as anchor points for the new physics- come what may. Prime examples in this category would include: the principies of Newtonian mechanics (at least in the limiting case), the principies of conservation of energy, Maxwell's electromagnetic theory (or sorne version of it) and the indispensability of an ordering of rhe chemical elements according ro aromic mass and number.

Finally it is pertinent to call attention to a number o f unsolved problems, puzzles and enigmas whose resolurion was to be of crucial importance for future direction of physics. These issues were given high priority by physi-

THE TRANSFORMATION OF PHYSICS 2 49

cists. For example, the assumption of a pervasive universal erher - the medium for all physical phenomena- was invoked asan intellectual necessity for explaining optical, thermal, electromagnetic and gravitational pheno -mena. The most recalcitrant problem connected wirh the ether was irs function, the properties needed in order ro fulfil that funcrion and the relation o f the ether - and sometimes of the pluraliry of ethers invoked - wirh mechanics, radiation rheo ry and views o n the constitution of matter. Perhaps matter or certain kinds of matter, electrons, for cxample, wcrc composed only of electricity. The puzzles were not resolved; their rcsolution depended on other puzzles- su eh as: what is electricity? and what is ether?

The paradigm example of a deep puzzle brought on by a phenomenon ro rally unconnected with classical physics and chemistry was the discovery in 1896 of radioactivity . The spontaneous and uncontrollable disintegration of certain elements found in nature, opened up for fertile study the nature, properties and reactions of matter, and the forces that operare at the leve! of the atom and che nucleus of the arom. The planetary theory of the atom, nuclear theory, the identification of elementary particles and particle-induced transmutations of elements ser the stage for the discovery of nuclear fission in 1939, just fifty years ago. When W. K. Clifford in the late r 87os reasoned, from the complexity of atomic spectra, that 'atoms must be at least as complexas a grand piano',32 he could not possibly have known that the internally strucrured atom would turn out to be severa! orders of magnitude mo re complex than anyone had anticipated. However, che nuclear atom was found ro be unmanageable not so much scientifically or technologically, but politically, and namely in those arenas of the world where the survival of mankind was ro be placed in che hands of the ma jor powers.

None of chis could have been foreseen. 1t all began with incense and innocent curiosity about the nature of the physical world. In 1902 Ernest Rutherford wrore to his morher from McGill University:

1 a m now busy writing up papers for publication and doing fresh work. 1 ha ve co keep going, as rhere are always people on my crack. 1 ha ve ro publish my presem work as rapidly as possible in order ro keep in rhe race. The best sprinters in rhis road of invesrigation are Becquerel and the Curies in Paris, who have done a grear deal of important work in rhe subjecr of radioacrive bodies during rhe past few years.n

NOTES

r For an analysis of rhe anrecedenrs ro rhe postI900 modificarions in laborarories in Brirain, see R. Svierdrys, 'The rise of physics laborarories in Britain', Historical Studies in the Physical Sciences, 7 (1976), 405-36.

2 There are nor many works in which fin-de-siecle physics has been analysed per se.

250 Erwin N. H iebert

A comprchensive invenrory of academic physics esrablishments ar rhe rurn of rhe ccnrury is provided by P. Forma n, J. L. Hcilbron and S. Wcarr, Physics circa r900. Personnel, Funding and Productivity of the Academic Establishments, Hisro rical Srudies in rhe Physical Sciences 5 (Princeron, N.J., r975). See a lso J. L. H eilbron, 'Fin-dc-siecle physics' , in C. G. Bernhard, E. Crawford and P. Sorbom (eds.), Science, Teclmology and Society in the Time of Alfred Nobel (Oxford, 1982.), pp. 51-73. By conrrast, thc works on fin-de-siecle lirerarurc, cu lrure, polirics and rhe a rrs are immcnse, especially for Austria and Francc. The German lireraturc on rhis period no rmally is rrcared under rhe heading o f j ahrhundertwende. Monographs in many languages rrear rhe period wirh perspecrives horh pos irive and negarive.

3 Ox(ord English D1ctionary, vol. Ili (19_'3), pp. SoS-9. 4 Oxford English Dictionary, Supplemenr, vol. 1 (1972. ), p. 537 5 P. A. M. Di rae, The Principies of Quantum Mechanics (Oxford, 1930), p. v. 6 The mammorh srrides achieved in foundarions of marhemarics, beginning with

C. F. Gauss in rhc middle of rhc nincteenrh cenrury, carne ro fruirion in rwenrierh-ccnrury physics in rhe work of pcrsons such as Fclix Klein, David Hilbert, Hcrmann Weyl and Hcrmann M inkowski. There were orher mathematicians who were less physics-orienred , bur whose conrriburions neverrheless rurned our ro be crucial for ad vanccs in rheoretical ph ysics: Leopold Kronccker, Richard Dedekind, Georg Canror, Gorrlob Frege, Giuseppc Peano and Berrrand Russcll.

7 H . Poincar, 'Relations entre la physique exprimenrale er la physique mathmari-que', in C. E. Gu illaume and L. Poincar (ed. ) Rapports prsents au Congres lnternational de Physique (Paris, 1900), vol. 1, pp. 1-2.9 .

8 A lisr of thcorerical chairs ar this time would include: Kirchhoff, Berlin, 1875; Lorenrz, Leiden, 1877; succeeded by Ehrenfest in 1912.; Voigt, Gottingen, 1883; Volkmann, Konigsberg, r886; Planck , Kiel, 1885; Bo lrzman n, Vienna, 1902.; Ernsr Pringsheim, Breslau, 1905; and Somrnerfeld, Munich, 1906.

9 See cspccially rhe arriclc of Shulamir Volkov , 'Soziale Ursachen des Erfolgs in der Wissenschafr. Judcn im Kaisserreich ', Historische Zeitschri(t, 2.45 (1987) , PP 315-42..

ro E. Du Bois-Reymond, 'ber die Grenzen des N aturerkennens' (1872.) and 'Die Sieben Weltriitsel' (188o), in Reden (Leipzig, 1886), pp. 105-40 and 381-417. The polemical statemcnr of 1872., on p. 130 reads: ' In regard ro the riddles of rhc material world the scienrist long ago has become accusromed ro pronounce his lgnoramus with brave rcnunciation [mit miinnlicher Emsagung] ... In regard ro the riddle abour rhe essence of marrer and force [Kraft], and how they are ro be co nccived, he once and for all must reach the m u eh more difficult decision ro accept rhe judgement: "lgnorabimus", (aurhor's translatio n). Unless indica red otherwise, all rransla tio ns from o riginal works are done by rhc author.

11 lnfluential wrirers of rhis persuasion would include rhc Swiss zoologist and philosophcr Karl Vogr, rhe Durch physiologist Jacoh Moleschott, the most influcntial nineteenth-cenrury German rnare ria list Ludwig Bchner, and the conrroversia l German morphologisr Ernst H aeckel. All were inAuenced by Ludwig Feuerbach. For an inte rpretarive and contcxrual hisrory of nincreenrh-cemury German marcrialism, wirh focus on Feucrbach, Vogt, Moleschott, Bchncr and

THE TRAN S FORMATION OF PHYSICS 251

Czolbe, see: F. Gregory, Scientific Materialism in Nineteenth Century Germany (Dordrecht, 1977).

12. Du Bois-Reymond, 'On rhe relation of natural science ro arr', Nature, 45 ( 1 891), 2.oo-4 and 2.2.4- 7. Addrcss delivered at the annual meeting of thc Royal Academy of Sciences in Berlin in r89o.

1} /bid., p. 2.00. ! 4 Jbid. 15 L. Bchner, /m Dienst der Wahrheit . Ausgewahlte Aufsatze aus Natur und

Wissenschaft (Giesscn, 1900) . Arricle on Karl Vogt (1896), p. 253-4. r6 Ihid., p. 2. 55 -17 L. Bch ner, Kra(t und Sto(( oder natrlich Weltordnung. Nebst einer darauf

gebauten Moral oder Sittenlehre. In allgemeinverstdndichler Darstellung (Frank-furt, r855). The English cdit ion first appcared in London in r884.

1 g L. Bchner, A m Sterbelager des Jahrhunderts. Blick eines freien Denkers aus der Leit in die Zeit (G iessen, 1898), quorarion on p. 9

19 Aparr from landmarks in Darwinian evo\ur ion, and che life and earrh sciences, Bchner accenruated whar he calls rhe great scienrific upheavals (Umwalzungen) of the cenrury: astrophysics, spectral analysis, photography, rhe reviva! of the Greek doctrine of immorrality of tbe arom, radiation studics, ferril ity of rhc crher concept, rhe kineric rheory of gases, che discovery of argon and X-rays, rhc liquefacrion and solidification of gases, the synthesis of o rganic compounds, and various technological accomplishmems, conspicuously in clectrochemistry and elecrrotcchnology (the fronrier science of rhc rwenricth century). lt is worth menrioning that Bchner refers ro the face-abours or upheavals (Umwdlzungen) in science - wirhout polirical overro nes or referencc ro ' revolutions' - in rhe same sense in which Friedrich Engels employed rhe expression in his Herr Eugen Dhrings Umwalzung der Wissenschaft (Leipzig, 1878).

2.0 Bchner, Am Sterbelager des jahrhunderts , p. 61. 2. 1 /bid., see cspecially pp. 141, 175, 2.29, 2.57 and 305. 2.2 /bid., p. 2.53 23 E. H aeckel, Die Weltrathsel. Gemeinverstiindliche Studien ber Monistische

Philosophie (Bonn, 1899), p . 3 The views of Lamarck, Darwin and Goerhe ('the religion of rhe true, rhe good and the beauriful', p. 464) werc given precedencc. Whereas the work dealt primarily with anrhropology, cosmology and psychology as a branch of physiology, ir also rouched upon physical principies such as rhe conservation of matter and energy, che kinetic rheory, chemical atomism and affiniry, and rhe imponderable ether (pp. 2.43-67). In spite of Haeckel's grandilo-quent ideas of culture, the Firsr World War brought forth 111 him, along wirh ninety-rwo of Germany's leading inrellecrua \s, suppo rr for a 'manifesto ro rhc civilized world' rhar 'affirmed the wisdom of German acrions and ended wirh the Aat assertion thar German cul ture and German militarism were inseparable' . See M. J. Klein, Paul Ehrenfest , vol. 1, The Making of a Theoret ic:al Physist (Amsrerdam, 1970), pp. 2.99-300.

2.4 G. Kirchhoff, Vorlesungen ber mathematisc:he l'hysik, 4 vols. (Lcipzig, 1876-94). The 4th edirion, reworked by Wilhelm Wien, appcared in 1897. Comprehcnsive

252 Erwin N. Hiebert

rexrbooks on 'classical physics' of rhis period and sryle would include as well: F. Neumann, Vorlesungen ber mathematische Physik (7 vols., Lcipzig, r881-94); W. Voigr, Kompendium der theoretischen Ph ysik (2 vols., Leipzig, r893-6); and H. von Helmholtz, Vorlesungen ber theoretische Physik (6 vols., r897-1907). For a succincr discussion of Gcrman physics rhrough rhc lasr quarter of the ninetcenth ccntury see: C. Jungnickel and R. McCormmach, Intellectual Mastery o( Nature. Theoretical Physics (rom Ohm lo Einstein , vol. 11 (Chicago and London, r986), ch. 14, pp. 125-48.

2.5 A. Michelson, Ught Waves and Their Uses (Chicago, 1903), pp. 23-5. A dccade befare this volume was published , its Po lish-horn author, then heading a new physics departmenr at the University of C hicago, had alrcady achieved an international repucacion with his exact interferometric techniqucs. In 1907 he became che first American ro gain the Nohel Prize, 'for his optical precision instrumenrs and the specrroscopic and mecrological investigacions carried out w ich their aid'.

26 Ibid., pp. 23-4-27 Sec for example: E. Hiehert, 'The energetics controversy and the new thermodyna-

mics', in D. H. D. Roller (ed.), Perspectives in the History o( Science and Technology (Norman, Okla, 1971), pp. 67-86, and idem, 'Developmenrs in physical chemistry at che rurn of the century', in C. G. Bernhard, E. Crawford and P. Sorbom (eds.), Science, Technology and Society in the Time o( Al(red Nobel (Oxford , 1982), pp. 97- 08.

28 1 may mention in this connecrion rhe most importa m developments: che discovery of Xrays in connection with cathode ray phenomena (Romgen, 1895); che demonsrration rhac a cachode discharge carries negative charge (Perr in, 1895); the announcemem of che discovery of the new chemical e lemenc argon as a monatomic gas chac had no valency, no chemiscry and no place in the periodic cable (Rayleigh, Ramsay, r895); che discovery of the spontaneous disincegration of certain elemems, i.e. radioacriviry (Becquerel, r896); che effecc of a magneric field on spectra , i.e. Z eeman's magnero-opcic effecc (1896}; che Wilson cloud chamber experimems on che parcicle-induced condensation of water vapour in gases (1897); che discovery of rhe elecrron as a parcide of di serete mass and negative c harge (J. J. Thomson, r897); che confirmarion rhar cathode rays are partides of high velocit y (a bouc one-chird che velocicy of lighr) and negacively charged (Wien, 1897-8); che discovcry o f che corpuscular narure, charge and velociry of posicive rays using combined e lecrric and magneric defleccions (r 898-9); che discovery and isolacion of radium and polonium from picchblende (che Curies, 1898); and che decailed and impressive cxperimemal invescigarions o n radioaccivity undercaken by Rutherford and his collaboraror, Soddy, while at McGill in Momreal between 1898 and 1907.

29 E. Hiebert, 'The srace of physics ar the rurn of che cemury', in M. Bunge and W. R. Shea (eds.), Rutherford and Physics at the Turno( the Century (New York, 1979) , pp. 3- 2.2; quotacion pp. s-6.

30 R. S. Woodward, 'The unicy of che physical sciences', Congress o( Arts and Sciences, Universal Exposition St. Louis 1904 (Boston, Mass., 19o6), vol. IV, p. 8.

3I /bid. 32 Quoted from O. Lodge, Atoms and Rays (London, 1924), p. 74

THE TRANSFORMATION OF PHYSICS 253

33 Quored from E. N. da C. Andrade, Ruther(ord and the Nature o( the Atom (Garden Cicy, N.Y., 1964), p . 55 The Nobel Prize for 1903 (discovery of spontaneous radioactivity and researches on radioactive phenomena) was shared by Henry Becquerel and Pierre and Marie ne Sklodowska Curie. Rurhcrford receivcd the Nobel Prize for chemistry in 1908 for his invcsrigations into rhe disintegration of radioacrive subsra nces.