Universal Evolution

[Lloyd Gillespie]

Lloyd;
The problem I see with this oneness approach is the same that I see with “WSM” forum approach, no functional mechanism for what constitutes a particle structure.[My model features a particle structure process in the universe's first finite singularity] Also this does not provide satisfactory explanations for the conservation laws and especially the concept of inertial mass.[My model accomplishes both of these with ease___it's a simple classical S1 motion of S2 motions explanation] This approach is one I tried over 30 years ago and it did not pan out then so I evolved my concept to the current 4 axioms.[David, I also tried, and even copy-righted, in 1991, the almost exact absolute motion model you are proposing___the only difference was I used two electrons approaching each other at absolute velocity___this was before I realized S1 space is non-quantumized linear only motion___herein lies the key___no Dirac sea angular particle impedance to S1 matter motion increase, thus allowing the possibility of high kenetic energy creation through high inertial mass increase] Though motion can vary within a system, the total will always be an absolute and thus the conservation of mass and energy are preserved even though they should be called conservation of matter and motion.[The conservation of matter and motion can also be conserved in an eternally unchanging S1 ground state containing the S2 finite state changes in matter motions___the key is first centered, first quantumized___then the true laws of conservation, we know, begin, not before___there's nothing to be conserved in the initial S1 state, as it's all one absolute thermal matter motion] There is no doubt that the thermodynamic interpretations of thermal behavior is a must in any real concept.

I don’t think you realize that I have thought these scenarios out over the past 40 years or so. I have not seen any new concepts that I have not tried in the past. If you apply these ideas to all the known facts of science and compare them to the functional mathematics, you will find that the oneness concept will indeed fail.[And I can show you where it won't fail.]

If you like, we can go into detail discussion of your concept and save mine for latter, or we can present both concepts side by side for comparison. What path would you like to take?

David, I think we need to present both at the same time, for comparrison clarity. This may pose difficulties, but I think it the most productive in the end, as this way we can correct and blend each's ideas into one truly workable model.

On another note, David, I think you should realize I also have thought these ideas through for over fifty years. I was raised in a family of scientists. I started work in the nuclear energy industry in 1969. Through the many years since, I have inter-acted and been friends with many physicists. I am still friends with many physicists, and I did grow up with some who work as IBM's, G.E's, and Dupont's top team physics leaders. I argue with them as much as you and others___I always have. David, I've been inside containment with the real high-rad-drifters. We've had the HP's showing us the ground base of staying alive under high radiation conditions for years. I've seen the prettiest light show known to man___peering into the reactor core when the lid is lifted off. It's so beautiful, it almost makes you want to jump in___though I'll pass on that one. Though I speak a different language than anyone talking about physics, I assure you I have been taught by the best, and even taught a few others much, myself. It's just the nuclear industry has an entirely different dialogue, since it's a mix of construction workers and physicists, etc., it's still a very effective hands-on process of schooling and learning. I happen to be one of the ones that's asked the really deep and hard questions for the safety physicists to answer, when all new trainees are going through classes___You'd truly be surprised what takes place behind those machine-gun guarded gates at nuke plants.

Regards,
Lloyd

[theunify]

In my opinion entropy does not mean speed, it means complexity.

Therefore if we keep absolute motion as being true, we would have to define entropy as number of particles.



We need to define a few things; Time=0, Time=1, and Time=2. Time=0 is what happened before the singularity was formed. Time=1 is the singularity, and Time=2 is the first 'step' of the big-bang.

What was the entropy change from Time=1, to Time=2? Was it finite, or infinite?

Are we getting into string theory? I believe we are.

[dleviwing]

We need to define a few things; Time=0, Time=1, and Time=2. Time=0 is what happened before the singularity was formed. Time=1 is the singularity, and Time=2 is the first 'step' of the big-bang.

JonD;
What definition of time are you referring to, time as measured by the clock, or time as a concept?

Either one still makes your comment quite meaningless to anyone other than yourself. Time is nothing more than a reference to allow us to quantify motion. It is not an entity of the universe in any manner. As far as entropy is concerned, I would suggest you stay with the concepts of thermodynamics; it works just fine.

If you are referring to a graphical rendition to the evolution of the universe, refer to the diagram in my blog entry “The Genesis Hypothesis”.

[Lloyd Gillespie]

David, the easiest way I know to clarify my thoughts from the present held thoughts of universal discussions is to state the universe in two distinct time phases___1.The infinite void space___2.The finite space. I classify all infinite void space as that space before first finite singularity, and all finite space as that space during and after first finite singularity, existing inside the infinite void space. The best scenario is for me to state S1 to designate the infinite void space, and S2 to designate the finite space. This way we may be able to achieve a considerable amount more clarity of our ideas, and their evolution, as I, you or others may see them.

1.Now, as to electromagnetic wave aether; I see this as the S2 reality of the Dirac sea of post first finite singularity, as truly quantumized Minkowsky/Einstein space. Electromagnetic wave aether is not of the S1 infinite void ground state, before first singularity___this S1 ground state is straight linear thermal motion, i.e., a complex weather system of the void/space's storm state, into hurricanes and tornadoes. Now, I know some see this as uniform motion and randomized motion, yet all quantumized motion must, at the same time, have an element of electromagnetic motion to it, as my model shows all high entropy[fast-high velocity] motion must possess some electromagnetic quantity, even the static electricity produced by my leather jacket on my leather seats is evidence of such, lightening is another, and as I'm sure you are aware of the plasma fields' easy transmissions of high voltages across great distances, i.e., gravity, just another motion field. Now, many may see these as other than motions, but I see them as nothing but varrying degrees of thermal motions, of differing entropy states and stages.

2.Thermal wave matter would be the ground state of S1 void space. In this ground state, only the absolute state of matter and motion exist, in their least dense matter/mass state, and the motion is the lowest entropy[velocity] possible to exist in a thermal temperature approaching absolute zero. This ground state, IMO, has a never changing quality and quantity to it, as its base state. Though it can maintain the initial ground state of low entropy motion and temperature, it also is possible for its inner-most extremities to change state, to form the weather systems of S1 void/space that would eventually, over trillions and trillions of years, produce the first finite singularity at its center, due to the very scientific properties of the thermal absolute matter wave state's changing state motions. The zero thermal temperature is naturally center seeking___this is just pure science___whether initial ground state___or performed by low temperature physics in the lab, i.e., the simple experiment of lowering a rose into liquid hydrogen, and measuring the shrinkage of the thickness to thinness of its petals before and after___the fact exists in both places___initial ground state, or lab experiment___extremely cold temperatures shrink most compounds and elements known to man. Of course, water is an exception, in its initial freeze stages, as may be some other elements, but most shrink dimension or contract, attract, bond, affinitize, or whatever you may wish to call it___most all elements at near zero thermal temperatures tend toward a center___as would have the initial ground state of the S1's infinite void space's absolute thermal matter motion. And, IMO, herein lies the key to your own self-affinity and bonding___it's just the entire S1 process is a trillions of years process from low entropy temperature and motion to high entropy temperature and motion___yet this changing state motion is the absolute of absolute matter's initial state condition. Even your own post's condition of "Matter is all in a void," is a ground state of one___so the one state is what we are both working from. As a matter of fact, it's your own four axioms that make the unity condition required to explain all the universe's motion conditions and states, of S1 and S2 space.

3.Now as to quantumized angular wave matter. I state this as a differentiation between S1 ground state void space and S2 post first finite singularity Minkowsky/Einstein space. I see no way to make our points clear to each other until we accept some format of realization of the confusions that otherwise exist between trying to discuss the before and after states of universal evolution, unless we clarrify them with S1 and S2 designations, so we all know what state is truly being addressed. This new dialogue is what will make it possible for us to build a truly workable linear S1 model that we can show possible of creating the truly workable angular/linear S2 quantumized model. Thus when I refer to quantumized angular wave matter, it should now be clear that I am only referring to S2 space, and I'll try to remember to add the S2 qualifier, or when stating the ground state, I am always referring to the S1 non-quantumized linear only state.

It's of course a considerable bit confusing to many, if they haven't followed all my posts, as the language I have developed in the previous posts to others has clearly mentioned all I have stated above, but it's scattered all across this board. I've just been furiously discovering new ideas and trying to develop the dialogue necessary to discuss these issues, that it's been almost impossible to consider all the links necessary to relate these new ideas, that have been boiled out of our, and others inter-actions. I'm sorry for being unclear at times, but I only have so much time to work on these issues. I'll try better in the future.

Regards,
Lloyd

[Lloyd Gillespie]

On the Co-Creation of Classical and Modern Physics

Richard Staley*


ABSTRACT
While the concept of "classical physics" has long framed our understanding of the environment from which modern physics emerged, it has consistently been read back into a period in which the physicists concerned initially considered their work in quite other terms. This essay explores the shifting currency of the rich cultural image of the classical/modern divide by tracing empirically different uses of "classical" within the physics community from the 1890s to 1911. A study of fin-de-siècle addresses shows that the earliest general uses of the concept proved controversial. Our present understanding of the term was in large part shaped by its incorporation (in different ways) within the emerging theories of relativity and quantum theorywhere the content of "classical" physics was defined by proponents of the new. Studying the diverse ways in which Boltzmann, Larmor, Poincaré, Einstein, Minkowski, and Planck invoked the term "classical" will help clarify the critical relations between physicists' research programs and their use of worldview arguments in fashioning modern physics.

DESCRIPTIONS OF THE TRANSITION from classical to modern physics have long provided the most powerful framework in which to present the great transformations in physical understanding that occurred at the end of the nineteenth century. However loosely, this language links the physics of the day to its era, gesturing at a common struggle through which fields as disparate as art, literature, and technology broke free of tradition to forge key elements of the modern world. While it pervades writings across the spectrum, from physicists through historians and popular authors, the origins of this framework are at present largely unknown. This essay aims to establish when and why physicists first started to think of "classical" and "modern" physics in the way we now take for granted.
Consider first a representative use of the concepts from a major protagonist. This will indicate the subtle historiographical situation we have to deal with. Describing his discovery of energy quantization in a 1931 letter to Robert W. Wood, the Berlin theorist Max Planck (18581947) wrote of his distaste for dubious adventures. But by 1900 he had been "wrestling with the problem of the equilibrium between radiation and matter for 6 years, without success." After finding an empirically accurate formula for the energy distribution in the spectrum of a blackbody in October, he deemed the final step of providing a theoretical interpretation worth any price. In his "act of desperation," there was an important casualty: "Classical physics was not sufficient, that was clear to me. For according to it, energy must, in the course of time, transform completely into radiation from matter. In order for it not to do so, we need a new constant that assures that the energy does not disintegrate [indefinitely]."1
Planck's invocation of classical physics is at once epochal in gesture and highly specific (his reference to the transfer of energy from matter into radiation is a brief account of the consequences of the equipartition theorem, a subject we shall return to). But despite the power and clarity with which Planck links the physics of an era with an emblematic principle, careful historical research has taught us to question whether he in fact won his way to modern physics in 1900.
In an extraordinary 1978 study, Thomas S. Kuhn argued that despite his formal use of energy elements in forging a new interpretation, Planck did not regard himself as introducing the radical new understanding of energy quanta we now associate with modern physics.2 Planck's 1900 papers support the point. Rather than emphasizing energy quantization or the law itself, Planck highlighted both its use of two natural constants, h and k (later named Planck's and Boltzmann's constants), and the quantitative links it established between electromagnetic theory and the properties of electrons and atoms. Planck had delivered new natural constants and opened glimmers of insight into the processes conditioning the largely inaccessible world of microphysics; but his writings show little evidence that he thought he had won a new kind of physics.3
Kuhn convincingly demonstrated that Planck did not articulate a broadly conceived quantum physics in 1900, even if the blackbody law was later taken to found one. But he held fast to the other side of the story, insisting that Planck's approach was still "fully classical," even as late as his 1906 Lectures on the Theory of Heat Radiation. Kuhn's recourse to this overarching interpretative framework is widely shared. Allan Needell and Olivier Darrigol have both suggested that "classical physics" is an idealization formed in the 1910s and that its application to the fluid situation of turn-of-the-century physics is anachronistic. Nevertheless, benchmark accounts of the period and its major figures routinely invoke the term in describing the conceptual environment in which physicists developed their research programs.4 Once again noting the power and clarity of this language, we need to question whether we should understand the physics of the era as "classical."
Analytically, one can offer a clear rationale for Kuhn's insistence. If quantization defines the new physics, and the classical and modern form two mutually exclusive theoretical stances, the fact that Planck makes no recourse to discrete energy values renders his approach classical by definition. Planck's 1931 letter shows that by then he held something like this analytic perspectiveand applied it to his earlier struggles. But noting that, just as he made no explicit use of the concept of energy quantization in 1900, Planck then made no explicit reference to "classical physics," this essay will address the question, When, why, and how did Planck and his community first start using concepts of "classical physics" in their work to shape new theory?
Given the widespread use of the language of the "classical" and the "modern" in fields as fundamental to European nations as education and as highly visible as art and technology, this empirical question holds the promise of establishing significant links between research physics and cultural history. It is important to note at the outset, however, that in turn-of-the-century schooling, art, literature, or science any particular deployment of these evocative but open words was likely to meet controversy and contest. After all, the debate over the status, values, and content of classical and modern approaches to secondary and tertiary education in 1890s Germany was so bitter that contemporaries described it as the "Schulkrieg."5 Given this environment, we will have to guard against reading a meaning into early uses of such terms that was in fact won only later.
I will focus in the first instance on the concept "classical," for specific deployments of that word were more significant than an invocation of "modernity" in the formation and propagation of new theory in physics.6 Searching for patterns of use rather than definitively first appearances, I present a comparative examination of three addresses surveying the state of physics circa 1900. This will show, first, that the word "classical" was then used in several distinct ways (some of them in considerable tension with others); it will also suggest that the word was employed differently in different language-speaking areas. In this early period "classical" was applied most concretely to mechanics. The following section will explore the relationship between a newly minted "classical mechanics" and the emerging theory of special relativity. The third section turns to early quantum theory, showing that the expansion of the concept of the classical to cover physics as a whole followed the development of a new understanding of statistical mechanics. Charting the long process through which physicists extended the meaning of the word "classical" will provide the foundation for my argument that classical physics and modern physics were very importantly created at the same time. Despite the power of Planck's retrospective application of the term "classical" to an entire epoch, classical and modern physics were co-creations, mirror image twins of the fault line between the physics of the past and that of the future.
FIN-DE-SIÈCLE PHYSICSBoltzmann's "Classical Physics"
By the end of the nineteenth century, Ludwig Boltzmann (18441906) had built an extraordinary reputation on the basis of pioneering work in statistical mechanics, interpreting the thermodynamic concept of "entropy" as a measure of the probability of a collection of atoms. His celebrated H-theorem explained the fact that entropy decrease is never observed in an isolated system as an essentially statistical property of a distribution of a large number of molecules (and his work provided the source and departure point for one of the most important features of Planck's new blackbody theory). In 1899 the Viennese physicist spoke on the methods of theoretical physics to a broad scientific audience at the annual meeting of the German Society of Natural Scientists and Physicians, the Naturforscherversammlung, in Munich.7 Like the other papers considered in this section, this was self-consciously a "turn-of-the-century" address, offering an overview of physics in a period of extraordinary and rapid change.8 Examining works of this kind will help us assess the extent to which diverse uses of "classical" were integrated with understandings of the content and character of disciplinary transformation. While we will soon see that Boltzmann's use of the term was idiosyncratic, it will indicate how deeply the earliest general invocations of such concepts were implicated in significant foundational debates. The distinctions we will recover between different invocations of "classical" theory in mechanics and thermodynamics have long been lost to our present concept of classical physics; but later sections will show how important they were to the formation of that concept itself.


Boltzmann introduced the concept of the classical in science as part of a sociological insight into methodological change. Approaches that had once looked capable of serving the development of science (or other disciplines like poetry, art, or music) forever might suddenly be revealed as exhausted, prompting attempts to find other, quite disparate methods. Then, Boltzmann wrote, followers of the old approach will find their point of view being described as outdated and outworn, while they in turn "will belittle the innovators as corrupters of true classical science." He held that this process recurs across the developmental history of all branches of intellectual endeavor:

Thus many may have thought at the time of Lessing, Schiller and Goethe, that by constant further development of the ideal modes of poetry practised by these masters dramatic literature would be provided for in perpetuity, whereas today one seeks quite different methods of dramatic poetry and the proper one may well not have been found yet.

Just so, the old school of painting is confronted with impressionism, secessionism, plein-airism, and classical music with music of the future. Is not this last already out-of-date in turn? We therefore will cease to be amazed that theoretical physics is no exception to this general law of development.9

Boltzmann's account shows how important it will be to recognize links to the cultural setting in understanding physicists' use of "classical." A significant local dimension animated his reference to secessionism, for example. Secessionism was pioneered in Munich from 1892; Gustav Klimt had recently founded a second secessionist movement in Vienna and was to stimulate extraordinary controversy with his paintings for the University of Vienna that reimagined traditional figures (see Figure 1).10 Perhaps the most important general point to emerge from Boltzmann's lists is his implication that, whatever their virtues, the new trends in art and poetryand physicsare likely to be less reliable than tried and true methods. But the specific way in which Boltzmann applies the word "classical" to his own discipline is even more interesting, because he depicts physics as being already in a postclassical phase.

(144 kB)Figure 1. The secessionist Gustav Klimt's sketch Philosophy, intended for the ceremonial hall of the new University of Vienna, was displayed in 1900 and survives only in this photograph. University academics repudiated its depiction of nebulous ideas in nebulous form, an indication of the stakes involved in reworking traditions. Boltzmann described mathematical phenomenologists as "moderate secessionists": Ludwig Boltzmann, "On the Development of the Methods of Theoretical Physics in Recent Times" (1899), in Theoretical Physics and Philosophical Problems: Selected Writings, ed. Brian McGuinness, trans. Paul Foulkes (Vienna Circle Collection) (Dordrecht/Boston: Reidel, 1974), pp. 77100, on p. 93. [Courtesy of Galerie-Welz, Salzburg.]

Boltzmann began by outlining the approach, fueled by the achievements of Galileo and Newton, that sought explanations along the lines of Newton's theory of gravitation (supplemented by repulsive forces). The task of physics had looked as if it might forever consist of seeking "the law of action of a force acting at a distance between any two atoms and then integrating the equations that followed from all these interactions under appropriate initial conditions." In the 1870s and 1880s the work of James Clerk Maxwell and Heinrich Hertz that developed and confirmed the theory of the electromagnetic field had broken through this program. One rich consequence was epistemological. Now, following Maxwell's understanding of the limitations of mechanical models and Hertz's insistence that understanding should be based on the equations, physicists recognized that it was not their task to say what reality truly is. Rather, they sought a picture [Bild] that is both as simple as possible and that represents phenomena as accurately as possible. J. L. Heilbron has noted that this "descriptionist" stance was characteristic of turn-of-the-century attitudes toward the aims of physical theory.11
In addition to the rise of new methods in electromagnetism, Boltzmann discussed philosophically motivated criticisms of the foundations of mechanics. Both Gustav Kirchhoff's 1876 lectures and, especially, Hertz's recent posthumous volume on mechanics had mounted what Boltzmann described as a formal and programmatic attack on "the old classical mechanics." Discerning a lack of clarity, their work had focused on providing a new treatment of the concept of force. In Boltzmann's view this remained a program for the distant future, one that had not yet superseded the old mechanics (and we should note that he left the critical contributions of his Viennese colleague and rival Ernst Mach unmentioned).12 Boltzmann's own endeavor had been toward an extension of mechanical principles in kinetic theory, promoting molecular and atomic approaches. Despite the respect in which he fought for an as-yet-unfinished program, Boltzmann characterized himself as a monument to ancient scientific memories, the only one who still grasped the old doctrines with unreserved enthusiasm: "I regard as my life's task to help to ensure, by as clear and logically ordered an elaboration as I can give of the results of old, classical theory, that the great portion of valuable and permanently usable material that in my view is contained in it need not be rediscovered one day."13
This is both the earliest and the most elaborate discussion of classical physics that I know. In it Boltzmann marks himself as the first and perhaps the only figure of the nineteenth century who understood himself to be a classical physicist. At least one of his students saw him that way (see Figure 2), but it is worth noting that few, if any, others took up or commented on Boltzmann's self-definition.

(47 kB)Figure 2. Der Naturphilosoph, a drawing of Boltzmann by his student Karl Przibram. Przibram also drew Boltzmann riding a bicycle. This image appeared as front material for John Blackmore, Ludwig Boltzmann: His Later Life and Philosophy, 19001906, Bk. 2: The Philosopher (Boston Studies in the Philosophy of Science, 174) (Dordrecht: Kluwer, 1995), p. vi. [Courtesy of Setsuko Tanaka.]

Boltzmann's conception of himself in these terms is likely to have been relatively recent. To my knowledge, he first wrote of "classical mechanics" in introducing his lectures on the principles of mechanics in 1897. Forgoing the urge to give the discipline "a completely new garb," Boltzmann there did what he could to avoid the problems facing mechanics by offering instead a representation that was as true as possible to "its old, classical form."14 It is revealing that these two adjectives appear together, and Boltzmann may well have been the first to bring the second into play. Those who pioneered criticisms of mechanics had framed them as critiques of current understandings. Mach and Hertz wrote, for example, of its "present form" and "customary representation."15
These critical developments provide one rationale for Boltzmann's delineation of a "classical mechanics." A second spur is likely to have been the different sense in which others were beginning to write of "classical thermodynamics"with both terms emerging as a legacy of vigorous debate on a possible energetic foundation for physics. From the late 1880s Georg Helm and Wilhelm Ostwald had championed energy as the primary concept in science, seeking to derive mechanics and ultimately all physical laws from an energy principle. In 1895 Boltzmann publicly opposed their methods at the Naturforscherversammlung in Lübeck, and subsequently disputants on both sides of the controversy used classical coinages to assert different continuities with tradition.
I do not yet know which came first. However, it is significant that Helm included a section on "classical thermodynamics" in his 1898 book on the historical development of energetics. Helm justified his linguistic choice by writing that the understanding of the relations between heat and work gained by the mid 1850s formed a complete system that was now so generally accepted and well established "that it can certainly be called `classical.'" He added that the label had first been given by "the opponents of all efforts to develop it further." Whoever was responsible for the first use of "classical thermodynamics," Helm probably saw good reasons to promote that term as a way of insulating thermodynamics from the strong dependence on mechanics suggested by phrases like "the mechanical theory of heat." The new terminology could thus serve to distinguish the phenomenological, energetic approach Helm took to thermodynamics from the very different stance pursued by Maxwell and Boltzmann. Their work on the kinetic theory of gases sought to provide proofs of the laws of thermodynamics on the basis of mechanical, molecular, and statistical models.16 As a result, Boltzmann's appropriation of "classical" to describe first mechanics and then his own personal aims may have constituted an attempt to wrest that word from opponents like Helm. His writings would claim "classical" from the more recent field of thermodynamics on behalf of what Boltzmann undoubtedly regarded as the even more fundamental and venerable field of mechanicswhich formed the basis for his own innovative and controversial contributions to thermodynamics.
Larmor's "Classical" Volumes
We can now see that early, general uses of the word "classical" played into contested terrain. Later sections will show how far twentieth-century uses came to depart from Boltzmann's example. First, however, it is important to see how others outside the German-language realm invoked the term. In 1900 Joseph Larmor (18571942) was a lecturer in mathematical physics at the University of Cambridge. In the mid 1890s, and drawing also on the work of H. A. Lorentz, he had reformulated Maxwell's theory of electromagnetism into what became known as an "electronic theory of matter."17 Larmor introduced negative and positive electrons as the fundamental carriers of electric charge and the sole constituents of matter moving in a sea of ether. The electrodynamics of moving bodies was central to his research, and Larmor used new space-time and electromagnetic transformations in which what later became known as the Lorentz transformations offered a way of explaining the null result of all attempted ether-drift experiments. The work of both Larmor and Lorentz provided fundamental ground for the subsequent development and reception of relativity physics. In 1900 Larmor published his best-known book, Aether and Matter, and gave a presidential address to the British Association for the Advancement of Science. Larmor was clearly responding to just the kind of vision Boltzmann offered, and the word "classical" recurred often. But he kept his discussion of change well apart from the terms in which he described the great works in his discipline.
Larmor spoke of a "classical treatise" on infinitesimal calculus and the "classical volumes" of the British Association, with their reports on the state of different fields in physics. He also described the modern theory of electric and magnetic phenomena as having received its "classical exposition" with the publication of Maxwell's treatise. Rather than identifying a broader tradition, Larmor thus used the word to convey the achievement of specific works. This is exactly how most nineteenth-century physicists used "classical": to describe theoretical or experimental work of the first rank that might constitute a standard or model, whether or not it could be regarded as complete or definitive.18 The most significant example is the series of papers and books republished as "Classics in the Exact Sciences" from 1889 under Ostwald's general editorship. Its first volume was a reprinting of Helmholtz's Erhaltung der Kraft of 1847, and by 1900 the series numbered 119 volumes.19 Among its many aims, this venture may have been a way of insisting that the sciences, like the arts, had their classics.
Despite the specificity of Larmor's references to "classical" publications, he was deeply concerned with the great changes physics had seen in general. While recognizing the increasing disposition to replace Newtonian dynamical principles with a descriptionist agenda that renounced causal relations, he finessed the consequences of Maxwell's work rather differently: "The question has arisen as to how far the new methods of aetherial physics are to be considered as an independent departure, how far they form the natural development of existing dynamical science. In England, whence the innovation came, it is the more conservative position that has all along been occupied."20
Larmor thought there were strong grounds for giving up the attempt to explain electrodynamics as the mechanical consequences of concealed structure in the ether, but he defended the continued relevance of a dynamical understanding of the ether and electronsmatter on a molecular levelthrough the principle of least action.
Poincaré on "The Classical Mechanics"
Our final fin-de-siècle publication comes from Henri Poincaré (18541912). Although known initially for his pioneering mathematical work in celestial mechanics, the theory of automorphic functions, and algebraic topology, Poincaré had become one of France's most respected and broadly honored scientists. In 1900 he gave keynote lectures at international congresses of mathematics and physics held in conjunction with the Paris World's Fair. His 1902 book La science et l'hypothèse gathered together recent addresses, moving through mathematics and epistemology to discuss current physics (Chapters 9 and 10 reprinted his speech to the Congress of Physicists). Offering a potent mix of practical scientific philosophy, prognosis, and prospect, the book became extremely well known, with German and English translations appearing in 1904 and 1905.21
After treatments of arithmetic and geometry, Poincaré began his section on "Force" with a chapter entitled "The Classical Mechanics." Without explicitly stating what this meant, Poincaré launched an attack on several concepts that had been central to mechanics since Newton and were increasingly being questioned, notably by Mach. Declaring that there is no absolute space, no absolute time, and no direct intuition of simultaneity and, finally, that it might be possible to enunciate mechanical facts with reference to a non-Euclidean space, Poincaré swept the slate clear before provisionally accepting the use of absolute time and Euclidean geometry.22 That provided the basis for an examination of the relations between concepts of force, mass, and the principle of action and reaction in an account of Newton's laws as conventions, experimentally founded without being amenable to experimental invalidation. Poincaré had set out an argument of this type in earlier chapters on the foundations of geometry. As Peter Galison has recently demonstrated, the term "convention" offers a bridge toward understanding the rich cultural associations at play in Poincaré's work. The philosophical dimensions of Poincaré's focus on that concept can also be linked to the central role of the adoption of specific conventions in various political and physical realms in which Poincaré was active as a scientist and bureaucrat.23
Poincaré discussed the approaches to mechanics of Kirchhoff, Hertz, and the "thread school" that Jules Frédéric Charles Andrade had described in 1898.24 Together with his own critical commentary, these alternatives provide a good reason for distinguishing the traditional approach as "the classical mechanics." But it is particularly important to note that when he discusses energeticism it becomes clear that Poincaré limited classical mechanics to Newton's laws alone, despite the apparently broad scope of his reference to the advances involved in moving from "the classical mechanics," "the classical theory," or "the classical system" to the energetic.25 Poincaré wrote, for example, of the principle of conservation of energy and Hamilton's principle as teaching more than the fundamental principles of the classical theory. They had both extended the realm of applications of mechanics and introduced new restrictions on the kinds of motion possible.26 Although his language is somewhat ambiguous, "classical" thus provided Poincaré with a way of distinguishing a particular interpretation in a specific field rather than describing an epoch or worldview.
When he turned to providing an overview of current science, Poincaré's discussion once again shared many features with Boltzmann's, although his writing echoes distinctively French concerns with economical images of the scientific machine.27 For Poincaré, rapid change had left foundations uncertain; the new radiations had opened up a new world. Scientific progress involved a continual interplay between the achievement of apparent simplicity and the recognition of new complexity. It was not image or ontology that provided secure foundations, but the true relations expressed in hard-won equations and, especially, in general principles. Rather than explanatory mechanisms, the true goal of physics was unity. His focus on a principle-based unity shows that, despite a similar diagnosis of its present state, Poincaré thought that the search for permanently usable features of past physics was to be resolved quite differently than through Boltzmann's emphasis on classical, mechanical foundations. Moreover, not a whisper of the classical system he discussed before enters Poincaré's treatment of the past or present aims of science in these chapters.28
Reaching across local research contexts toward international and national registers, addresses and books of this nature also constituted conscious attempts to move between the concerns of research physics and broader, nonspecialist audiences. Disclosing a traffic of resonance and meaning between the research front and the public that is both multivalent and multidirectional, they provide important openings for a study of links between science and cultural history.29 In particular, building up a sense of the understanding of change they display has now given us an appropriate touchstone for evaluating different invocations of "classical." Circa 1900, "classical" was a concept with a range of uses. It is especially important to note thatin expressing the value accorded outstanding contributions or designating in particular traditional (but contesting) approaches to mechanics or thermodynamicsthe word formed only a minor part of the vocabulary with which physicists discussed the past and considered change. Physicists shared an understanding that their discipline had witnessed a long-standing criticism of foundations and the rise of new programs, especially following the success of Maxwell's work. Change was rapid, the field open. Boltzmann alone gave the term "classical" a highly general and importantly sociological meaning, and it is therefore in the German-speaking world that we can see emerging the possibility of speaking of "classical physics" or "classical physicists." This view is supported by different editions of La science et l'hypothèse. In the original, Poincaré confined "The Classical Mechanics" to Newton's laws alone and referred in passing to the classic system of electrodynamics, incomplete as it was. Significantly, Ferdinand Lindemann's preface to the German edition described Poincaré's discussions as extending to the whole of theoretical physics, both "in its classical form as well as in its most recent development." In a German reading, Poincaré's account of change could be subsumed within an epochal understanding of the past as classical. As it happens, Joseph Larmor wrote the introduction for the 1905 English edition and never used "classical" so broadly.30
But do all these fine distinctions in the use of an open and more or less general concept matter? Is this just splitting hairs? To understand how thoroughly particular uses of the concept of the classical could enter the practice of physics and shape perceptions of its periodization, we need now to consider their role in the development of two new theories. Histories of relativity and quantum theory are commonly used to draw conclusions about the nature of modern physics and the struggle required to break free of the classical past. Here I will move in just the opposite direction, analyzing uses of the concept of the classical within these theories themselves in order to shed new light on their development. In this regard, relativity and quantum theory reveal very different dynamics, incorporating concepts of classical theory in different ways and at different times. Displaying these differences will highlight the extent to which the concept of classical physics we now accept was both constructed in the light of the modern and defined by proponents of the new.

[Lloyd Gillespie]

On the Co-Creation of Classical and Modern Physics [cont...]

Richard Staley*


THE "CLASSICAL" AT WORK: CLASSICAL MECHANICS AND RELATIVITY A full account of the history of special relativity would take us too far afield, but it is important to note that Albert Einstein's 1905 paper emerged within an environment in which physicists developing electron theory had begun to take on the mantle of revolutionary figures, offering electromagnetic foundations for a new worldview. As the constituent in many recently discovered radiations, the electron made an empirical unification possible. A reductive theoretical unification was offered by the prospect (first advanced by Larmor) that its entire mass could be explained electromagnetically as resulting from the motion of a charged body through its own electromagnetic field. This exciting alternative to previous attempts to explain nature mechanically or energetically was championed by Max Abraham, among others.31 Aiming at a worldview based on Maxwell's theory by beginning with the particle that linked ether and matter through its charge (an element quite foreign to Maxwell's original formulation), the electromagnetic program embodied the central importance fin-de-siècle physicists attributed to Maxwell's work as a turning point. Theorists drew a sharp contrast with the mechanical worldview in particular. For example, seizing on the electromagnetic explanation of the electron's mass, the German physicist Wilhelm Wien highlighted the prospect of "founding mechanics on electromagnetism." Lorentz had developed a conception of the law of gravitation that related it to electrostatics, and it seemed possible to assume that all matter was composed solely of positive and negative electrons.32
New foundations were one focus of many physicists' research. Much later, for example, Albert Einstein (18791955) would describe his work in this period as an attempt to explore the general implications of Planck's radiation law for electromagnetic foundations of physics. After graduating from the Swiss Federal Institute of Technology in 1901, he devoted several years to analyzing perceived lacunae in Boltzmann's studies and developing an independent approach to statistical mechanics (he was an avid reader of Poincaré's Wissenschaft und Hypothese, too). Jürgen Renn has usefully characterized his approach as an interdisciplinary atomism that sought to unify disparate fields of study through a consistent mathematical framework.33 By 1905 Einstein's reflections on a broad range of fields reached fruitful maturity, and he commenced a series of papers that offered new approaches to the study of light, molecular theory, and electrodynamics and electron theory. His work in the last of these fields provides the clearest expression of his engagement with a second widespread concern: the status of and extent to which various more or less long-standing principles were applicable in the new fields of electrodynamics. As a consequence of his decision to extend the principle of relativity from mechanics to electrodynamics, Einstein first embarked on a fruitless search for an alternative electrodynamics. In 1905 he recognized that a new analysis of the concept of time and simultaneity, together with the assumption that the velocity of light was a constant (independent of the motion of the source), would allow him to reconcile Lorentz's theory with the principle of relativity.34


When did the concept of the classical appear in this mix? The development of electron theory and electrodynamics was very directly linked to the kinds of questions that had been put to traditional mechanics for many years and explicitly raised the possibility of both new foundations for and new forms of mechanics. Relationships between past, future, and present theory were central; but physicists found a variety of ways of expressing this. Poincaré, for example, finished his discussion of the principles of mathematical physics at the International Congress of Physicists held in St. Louis in 1904 with the suggestion that perhaps physicists should

construct a whole new mechanics, of which we only succeed in catching a glimpse, where inertia increasing with velocity, the velocity of light would become an impassible limit.

The ordinary mechanics, more simple, would remain a first approximation, since it would be true for velocities not too great, so that we should still find the old dynamics under the new.35

Einstein's work linking electrodynamics and mechanics through two principles led him to develop a fundamental realization of the program Poincaré pointed toward. Revealingly, in a now-famous letter to his colleague Conrad Habicht in May 1905, Einstein described his light quantum hypothesis as revolutionary and his paper on relativity as employing a "modification of the theory of space and time."36
Einstein abandoned absolute space and absolute time. Nevertheless, his new concepts of space and time depended strictly on measurement processes in a stated frame of reference. They could be understood as requiring only a modification of the old theory. In his 1905 paper, Einstein asked readers to consider a coordinate system "in which Newton's equations of mechanics are valid" when setting up the theoretical framework to derive transformation equations that would move between a frame of reference at rest and one in uniform motion. His work took up a topic of major concern in Germany, and much early discussion centered on understanding its relations with previous theory, especially mechanics and Lorentz's electrodynamics. Planck's first published response to Einstein's paper was an investigation of how the "ordinary Newtonian equations of motion" could be generalized in accordance with the principle of relativity. He showed that equations of motion could be established in the Lagrangian and Hamiltonian form and later went on to discuss the principle of least action in relativity.37 Clearly, recognizing that Einstein's approach allowed a reformulation of existing mechanics in its different forms was important to physicists' work to understand and extend relativity. And note Planck's terminology here: his language, like Poincaré's, will provide a sensitive indication of physicists' readiness or reluctance to bring new labels to mechanics.
By late 1907 Einstein was ready to do just that in a major research review of relativity. There, explicitly following Planck while diverging from his language, Einstein showed that a specific vector played the same role in relativistic mechanics as the force vector in "classical mechanics." He described the reformulations of the equations of motion of material points he drew from Planck as demonstrating, "so clearly," "the analogy between these equations of motion and those of classical mechanics."38 Einstein's terminology probably stemmed from his awareness of Boltzmann's work and Poincaré's Wissenschaft und Hypothesebut he did not retain the distinctions Poincaré had stressed. We will soon consider the connotations of this reference to the "classical"but first we must come to an appreciation of the extent of its use within the physics community.
In addition to addressing the relations between Lorentz's and Einstein's work, the Göttingen mathematician Hermann Minkowski (18641909) soon engaged in a treatment of "classical mechanics" even more extended than Einstein's. In his important 1908 paper on the fundamental equations of electromagnetism in moving bodies, Minkowski sought to combat the suggestion that "classical mechanics" was in opposition to the postulate of relativity as it had been developed as the basis for electrodynamics.39 Minkowski offered a general form of transformation equations in which the constant c appeared. He then showed that "classical mechanics" could be understood as involving invariance against the form that the transformation equations took when the constant c was assumed to be infinite. According to the new postulate of relativity, in contrast, the constant took a finite value, that of the velocity of light; and the traditional assumption could be regarded as an approximation to the exact invariance of natural laws for this finite value. The last section of the paper showed that replacing infinity with the finite constant c allowed the axiomatic structure of mechanics to be brought to substantial completion. Interestingly, in his celebrated lecture on space and time to the broader audience of the Naturforscherversammlung in Cologne in 1909, Minkowski did not use the language of the "classical" but wrote instead of Newtonian mechanics.40
Together with papers from Lorentz, the experimentalist Walter Kaufmann, and Planck, the work of Einstein and Minkowski provided the most important original source for many physicists' understanding of the emerging field of relativity theory. Einstein's and Minkowski's discussions assume the transparency of "classical mechanics" and are unlikely to have led to serious confusion. Nevertheless, it is worth focusing on the term for a moment. We noted previously that to use the phrase "classical mechanics" was to enter contested terrain. In fact Boltzmann's formulation proved controversial, both along an atomistic/phenomenological divide implicated in the energetics debate and as a reflection of different historical judgments. Paul Volkmann, for example, wrote that atomism and the existence of central forces without exception certainly did not characterize "the system of mechanics as classic, in the sense of its development from Galileo and Newton up to the present times." His historical continuum contrasted with Poincaré's focus on Newton, which itself differed from Aurel Voss's description of "The System of Classical Dynamics" as involving "something like the teachings that had succeeded to general acceptance through the influence of French mathematicians in the first half of the nineteenth century."41
What should be understood as "classical" in mechanics, then, was open to debate. Planck's example indicates clearly that physicists were able to recognize and elaborate the relationship that Einstein and Minkowski described as holding between an old and a new mechanics, without using the adjective "classical." Even Minkowski's protégé Max Born declined to follow his teacher's 1908 usage in a major paper on a rigid-body electron in which the foil was instead the "old" or "customary" kinematics.42 The choice such physicists made to qualify "mechanics" with a term other than "classical" may have stemmed from uncertainty about the presumed content of "classical mechanics" (even though Einstein and Minkowski used the phrase inclusively, without any explicit reference to the doctrinal issues implicated in earlier discussions). It may also reflect a reaction against the broader connotations of the termpotentially linking mechanics to cultural values in other fields and involving a very different set of associations than either "mechanics" alone or alternatives like "ordinary," "customary," "Newtonian," or the "old" mechanics.
Just what the connotations of "classical" were was likely to be changing subtly as the word was freed of its original association with particularly important works, whatever their nature, to find more general uses. In his 1909 book Great Men Wilhelm Ostwald expanded the meaning of the word still further to describe a characteristic type of scientist. Julius Robert Mayer, Michael Faraday, and Hermann Helmholtz were all exemplars of what Ostwald called the "classical temperament." In contrast to temperamentally romantic counterparts like Humphry Davy, Justus Liebig, and Charles Gerhardt, they displayed a slow spiritual reaction time and a steady spiritual heartbeat. Ostwald's coinage helped him frame psychological insights into leading figures in the chemical and physical sciences, and the book went through four editions within a year.43 Still other valences would have been imported from the way that a distinction between classical and modern approaches was invoked in fields outside physics. It is difficult to gauge the precise effect such connotations might have had, but it is worth stating that we cannot assume that they were always read as favoring the newespecially early in the century. Many contemporaries, scientists among them, took a notably wary approach to modern art like cubism and to modern forms of schooling, with their stress on contemporary languages and business needs rather than classical languages and traditional educational values. In Germany, for example, bureaucratic reforms in 1900 decreed that the two major forms of secondary education were now to have equal standing with regard to pupils' entrance into university studies. Similarly, technical institutes won the ability to award doctorates in 1899. But despite formal parity and heated discussions about the appropriate content of different educational streams, contemporaries would have had little trouble identifying the forms of education suitable for the intellectual elite. "Classical" certainly meant traditionalbut also current and foundational.
In this period, then, the word "classical" was being employed more frequently, particularly within Germany; its range of meanings was being expanded; and, as a result of new uses, its connotations were probably changing. In such an environment German physicists proved increasingly ready to apply it to what they might otherwise have described as "customary" or "ordinary" mechanics but often did so somewhat self-consciously. In lectures published in 1910, for example, Max Planck wrote of the transformation that was under way "from the so-called classical mechanics of the mass-point, which has until now been assumed to be generally valid, towards the general dynamics arising from the principle of relativity."44
Planck's linguistic caution is revealing and his adoption of the new term illustrative. The language of Einstein and Minkowski was to be widely copied in the next decade, making its way into textbooks and popularizations. In 1911 Max Laue began the first textbook on relativity with a section on the principle of relativity as it was used in classical mechanics, followed by a discussion of the great changes that applying the principle to electrodynamics had wrought. Ludwig Silberstein's 1914 English-language text The Theory of Relativity, similarly, drew a contrast between the principle of relativity of classical mechanics and the modern doctrine of relativity. Silberstein's background in German was important. In contrast, Ebenezer Cunningham compared Newtonian dynamics with the more general principle of relativity. In general, English authors held different understandings of relativity, much more strongly shaped by Larmor's work, than those in Germany; and the linguistic framework within which they discussed the theory was also subtly different.45 The same is true of physicists from other nations. For the widespread international use of common concepts of the classical in physics, we will have to wait on the development of quantum theory, discussed below, and on the popularization of relativity from 1919. By the time Einstein published his popular account of special and general relativity in 1917, however, we can say that within the German physics community, at least, the specific meaning physicists had given the word "classical" in their application of it to mechanics and quantum theory was likely to overshadow the connotations it still summoned from other cultural realms.46
What have we seen so far? Initially developed to describe a contrast with several critical, nontraditional interpretations of mechanics and often enmeshed in doctrinal debates, the concept of classical mechanics was soon transferred to discussions concerning relativity, particularly in Germany. There it was used more inclusively and increasingly widely, without ever completely displacing alternative terms like "customary" or "old" mechanics. In major texts and popularizations, however, "classical mechanics" was introduced as a foil to a new, more general dynamics that involved modifications or transformations of its key concepts. It is worth emphasizing that this involved a highly specific relationship between the old and the new. Within the German physical community, the "classical" had now been incorporated within the modern. For those working with relativity, these were not rival methods vying for attention in the way Boltzmann depicted the classical and the new as engaged in a competitive struggle to claim the future. In the context of its specific uses in mechanics, the classical/modern divide had become instead a relationship of historical succession and conceptual incorporation of the old by the new. It expressed the successful reworking of the traditional (mechanics) into a new framework for knowledge.
It is important to note, however, that this is still not classical physics, but a more limited and defined subset of the physics of the past. To understand why this is the case, we need to remember that there were already revolutions afoot, involving new foundations in the endeavor to replace the mechanical worldview with the electromagnetic worldview. Over time, relativity changed the nature of this debate, in part through its adherents beginning to describe the lineaments of a worldview in which the principle of relativity held a primary place and in part through efforts to break through the primary distinction between mechanics and electrodynamics that animated much contemporary discussion. Einstein and Planck both expressed these imperatives. In a 1909 address on the unity of the physical worldview Planck pressed the point, writing that electrodynamics and mechanics could not be sharply separated. After all: did the emission of light belong to mechanics or to electrodynamics? He thought the distinction between reversible and irreversible processes would be more important to the physics of the future.47 Planck's concerns on that score were closely related to blackbody radiation. Now let us turn to that subject, for we need to look beyond "classical mechanics" and relativity to arrive at the concept of classical physics we now accept.

[Lloyd Gillespie]

On the Co-Creation of Classical and Modern Physics [cont...]

Richard Staley*

THE "CLASSICAL" AT WORK? QUANTUM THEORY (19001910) The fine studies of Kuhn, Needell, Darrigol, and Martin Klein have shown that the two sides of what we now think of as the quantum revolution were in fact developed separately and to some extent independently. That is: in the decade following 1900, Planck's work was increasingly recognized as having founded a new quantum physics rather than being thought of primarily as an extremely successful law of blackbody radiation. In this process, the argument that it contradicted previous theory was as important as the recognition that it involved quantization of energy. In regard to the latter, historians have shown that in 1905 and 1906 James Jeans, Albert Einstein, and Paul Ehrenfest wrote papers in which they argued that the finite size of the constant h in Planck's formula involved a new treatment of energy. Their deep familiarity with statistical mechanics in general and Boltzmann's studies in particular enabled them to reach this understanding, and the relative rarity of both skills goes a long way toward explaining why the argument was not made until so many years after Planck's interpretative papers appeared. This interpretation of the importance of h followed from their recognition that Planck's formula involved a subtle departure from the combinatorial approach Boltzmann had taken to gases.
The first argumentthat prior theory also gave an answer to the blackbody problem, in conflict with Planck's lawdepended centrally on understandings of the equipartition theorem and its application to matter and radiation. This argument, detailed below, was first stated at about the same time that Planck was composing his important papers in 1900, and the equipartition theorem is now uniformly identified as providing the "classical" approach to blackbody radiation (known as the Rayleigh-Jeans law and resulting in the "ultraviolet catastrophe"). Planck's 1931 letter to Wood puts the matter in these terms, for example. Despite this present linkage, I will show here that the language of the "classical" entered quantum theory in a very different way than its early incorporation in relativity physics: it came late and into far less promising ground. Indeed, the equipartition theorem had been controversial from its origins in the 1870s, was always recognized as being inadequate in its application to blackbody theory, and was first described as "classical" only in the papers and discussions surrounding the 1911 Solvay Council. The equipartition theorem, then, was made classical, a process that simultaneously extended the conceptual reach of that word to cover far broader theoretical expanses than mechanics alone. This amounted to the christening of a new form of classical physics, turning on a very different epochal fulcrum than the one Boltzmann had described. Subsequently, both the specific, emblematic identification of the equipartition theorem as classical and the broader notion of the existence of a classical form of physics in the nineteenth century have consistently been read back into a period in which the physicists who used the equipartition theorem originally considered both the theorem itself and the complex of theory into which it played in quite other terms. The following sections will explain, first, why the language of the "classical" came late to this field and, second, whywhen it didit came in a veritable flood.
"The Boltzmann-Maxwell Doctrine of the Partition of Energy" and Blackbody Radiation, 19001910
The equipartition theorem was an important component of statistical mechanics as it had been developed by Maxwell and Boltzmann; it held that in any mechanical system at thermal equilibrium each degree of freedom will possess the same average kinetic energy.48 Both its authors recognized difficulties in applying the theorem to measurements of the specific heats of gases, and from its inception it had met a determined critic in William Thomson, Lord Kelvin. Indeed, in the fin-de-siècle address best known today, Kelvin chose to focus on two critical problems facing the dynamical theory of heat and light. The first problem he pointed towhich is now the notorious objectionwas the failure of the celebrated Michelson-Morley experiment to detect the earth's motion through the ether. But Kelvin actually devoted far more attention to the second problem, stating that he had "never seen validity" in Maxwell's proofs of equipartition. Kelvin held the "doctrine" extremely unlikely to be true, despite its attraction as a statement in pure mathematical dynamics. But in considering its implications for thermodynamics, and finding it destructive of the kinetic theory of gases (its first and most obvious realm of empirical application), Kelvin could not help but describe equipartition of energy as a "cloud" on dynamical theory. Responding to what John William Strutt, Lord Rayleigh, had recently described as "the destructive simplicity of the general conclusion relating to partition of energy," Kelvin suggested that physicists should simply deny the conclusion and so "lose sight" of this particular cloud.49
Indeed, Planck and the many others who first used his law without investigating its theoretical basis took no apparent notice of the equipartition theorem, and for several years it played only an occasional role in physicists' treatment of the blackbody. In 1904 the American physicist Carl Barus offered an overview of recent physics that shows that it was then still possible to treat equipartition and blackbody theory quite separately. In perhaps the most extraordinary address in its genre, Barus ran through more than a thousand important works in the history of modern physics, under thirty-six headings. He also suggested the value of some august tribunal formally canonizing "researches of commanding importance"; the word "great" conferred his highest praise, and "classic" was used but four times. Discussing the kinetic theory of gases, he wrote that "the difficulties relating to the partition of energy have not yet been surmounted. The subject is still under vigorous discussion." Without mentioning Planck, he discussed the blackbody in his section on radiation, describing it as the means for developing a new pyrometry.50
Despite this early separation, our present understanding of turn-of-the-century physics has been deeply marked by links that were forged, over time, between blackbody radiation and equipartition and what later came to be termed "classical physics." Lord Rayleigh became the first physicist to apply equipartition to blackbody theory in 1900 (without making any reference to classical theory). Rayleigh recognized a problem that arises if the theorem is taken to apply to the combined system of matter and radiation in the blackbody, given the fact that radiation in a continuous medium possesses an infinite number of degrees of freedom (even in an enclosed volume). That led to clear conceptual difficulties and implied that if energy was to be equally distributed to each degree of freedom it would ultimately drain away from matter with its finite degrees of freedom, leaving the walls of the blackbody cold. Accordingly, Rayleigh developed a formula in which equipartition applied to the energy distribution for radiation of long wavelengths but was prevented from coming into play for short wavelengths or high frequencies (the ultraviolet part of the spectrumhence later descriptions of the need to avoid the "ultraviolet catastrophe").51
Rayleigh's note drew little immediate comment. However, between 1905 and 1906 Jeans, Einstein, and Ehrenfest argued that there was an alternative form of the blackbody law, based on equipartition, thatdespite very evident empirical and conceptual limitationspossessed a clearer theoretical foundation than the law Planck had developed. Nevertheless, while all three refused to lose sight of equipartition, none described it as representing "classical" physics. Here I will try to explain this fact, before describing the terms in which they did state important contrasts between Planck's law and alternative understandings.
One important reason why the argument was not described as "classical" stems from physicists' recognition of the controversial status of the equipartition theorem in particular. A second relates to perceptions of the status of statistical mechanics and the molecular theory of heat more generally, especially given contemporary concepts of "classical thermodynamics." We have seen that Einstein referred to "classical mechanics" in his papers on relativity. A similarly specific concept of earlier and classical theory was also at play in his work on heat and molecular theorybut this probably precluded him from applying that term to equipartition.52 In two papers on kinetic theory and Brownian motion, published in 1905 and 1906, Einstein drew a contrast between "classical thermodynamics" and the molecular theory of heat similar to that outlined in my discussion of Boltzmann. Even more pointedly, in 1909 he discussed a weakness in Planck's use of probabilities in the calculation of entropy. Here Einstein distinguished a "classical" thermodynamical approach to irreversibility from the interpretation offered by the statistical theory.53 The contrast was between an absolute thermodynamics (which indeed Planck supported), in which maximum entropy was a single definite state that a system maintained once it had been reached, and the statistical approach to irreversibility, in which maximum entropy was simply the most probable condition, with a system assuming a random sequence of states over time. For Einstein, statistical mechanics and the molecular theory of heat represented nonclassical thermodynamics; the equipartition theorem was a central component of statistical mechanics.
A further reason for the absence of references to "classical" theory concerns broader perceptions of these physicists' research programs. James Jeans is the physicist who accorded the equipartition theorem the most important role in his approach to blackbody radiation. In the exchange that led to the exact specification of what became known as the Rayleigh-Jeans law, he argued that when the mixture of radiation and matter involved in a system like the blackbody reached thermodynamical equilibrium, kinetic energy would indeed be distributed equally through all degrees of freedom. Jeans denied, however, that the empirical blackbody ever reached equilibrium. Instead, he offered an account of the way molecular collisions would set up vibrations in the ether of particular periods (thereby distributing energy to long wavelengths of radiation) that showed why energy would not be transmitted to short wavelengths, except over millions of years. Later commentators have often described Jeans as a "classical physicist" for his defense of equipartition; but his contemporaries regarded his approach as a radical departure from the traditional role of equilibrium in the establishment of thermodynamical and statistical arguments and are highly unlikely to have described his endeavor in such terms.54
For all these reasons, turn-of-the-century physicists would have been unlikely to invoke a classical/modern distinction between equipartition and Planck's work. But those concerned did point to fundamental divisions in revealing terms. Jeans presented the contrast as one between Planck's theory and Newtonian mechanics, asserting that it centered on the recognition that Planck's theory required the energy of radiation to assume an atomistic form.55 Einstein's wide-ranging research led him first to advance the light quantum hypothesis in 1905 (on the basis of an examination of the form of Wien's law in the high-frequency part of the blackbody spectrum). In 1906 he argued that Planck's radiation law had made implicit use of the light quantum hypothesis, and a year later he extended quantum theory to solid bodies in his theory of specific heats. On these occasions Einstein contrasted quantum theory with prior expectations in different ways. For him, the consequences of Wien's law, Planck's theory, and the implications of the latter for molecular theory showed the limitations of, respectively, continuous, field-based theories, the energy relations that could be derived on the basis of Maxwell's theory and electron theory, and molecular-kinetic theory and the laws derived from our world of sense perception more generally. Ehrenfest also recognized broad differences, but he posed them first in terms of analyzing the distinctions between Planck's work, the research of Boltzmann on which Planck had drawn, and the alternative approaches taken by Lorentz, Rayleigh, and Jeans.56
The discussions of Ehrenfest, Einstein, and Jeans were highly important in building a context in which Planck's work could be interpreted as involving an energy quantization in conflict with prior theory. In 1906 Planck responded to their argument concerning equipartition by stating simply that he thought the problems came from an unjustified application of that theorem to all degrees of freedom.57 Despite the importance of these contributions, Kuhn's account picks out two later events that were still more significant in persuading physicists to take Planck's theory and quantum discontinuity seriously. These were the controversy surrounding Lorentz's support of the equipartition theorem in 1908 and the empirical support Walther Nernst provided for Einstein's quantum theory of the specific heat of solids from 1910. In each case the key published papers made no reference to the "classical."58 Quantum theory also began to make its way into survey articles from about 1909, there taking a place alongside electron theory and relativity as one of the most pressing problems of the day. In this forum also, however, papers by Einstein, Larmor, Planck, and Lorentz show that radiation theory was described primarily as a challenge to current understandings of the electron and statistical mechanics, both notably open and fluid fields.59
In summary, then: Up to at least 1910, Planck's quantum theory was presented as involving important departures from fundamental conceptionsin particular from the continuum approach to energy implicit in Maxwell's theory, from Boltzmann's statistical combinatorics, and/or from the equipartition theoremand it was described as being in conflict with current conceptions, especially of electron theory. It was not presented in the language of the "classical." Indeed, when that language was invoked, its use in relation to "classical thermodynamics" probably ran counter to any tendency to ascribe statistical mechanics or the equipartition theorem a classical status.

[Lloyd Gillespie]

On the Co-Creation of Classical and Modern Physics [cont...]

Richard Staley*

THE SOLVAY COUNCIL OF 1911 AND THE CHRISTENING OF CLASSICAL THEORY In 1911 this was to change, largely through the proceedings of an event that has sometimes been described as marking the birth of modern physics. The first Solvay Council in physics, convened by Ernest Solvay in consultation with Walther Nernst, was devoted to current problems in quantum theory. A handpicked group of eighteen physicists from Germany, France, Austria, Holland, Britain, and Denmark (with three scientific secretaries) took part. As it turned out, the congress saw no substantially new contributions to the research literature. Much more original was the widespread introduction of the term "classical" to the field. The preceding section has demonstrated that physics might never have been described as "classical" in the sense we now recognize. Now we shall see that it was the proponents of the new who fashioned this description.
Writing to Solvay in July 1910, Nernst argued that "we are currently in the midst of a revolutionary reformulation of the foundations of the hitherto accepted kinetic theory," emphasizing strongly how foreign Planck's and Einstein's use of energy quanta was to previous conceptions. Famously, a month earlier Planck had written to warn Nernst against holding such a conference too early. He thought more supporting evidence and a more widespread consciousness "of an urgent necessity for reform" would be required to ensure its success. Planck's letter is highly interesting. First, it shows how few people he thought shared his basic concern with quantum theory (from Nernst's list of potential participants Planck picked out only Einstein, Lorentz, Wien, and Larmor as seriously interested). Second, like Nernst's letter, it underlines the importance of the rhetoric of reform in prompting any deep concern with Planck's theory (in common with the earlier fields of electron theory, the electromagnetic worldview, and relativity). Finally, note that in it Planck adopted the passive voice, minimizing the role of human agency. Waiting a while would ensure success: let one orbettertwo years pass, "and we will see how the crack which has developed in the theory continues to grow until all those who are now outside the problem will be drawn into it." Such a process has a normal course, and Planck doubted that it could be accelerated.60
In the event, the Solvay Council held in November 1911 probably exceeded expectations, and no one worked harder than Planck and Nernst to widen the fissure Planck had identified. Participants arrived in Brussels well prepared. Their invitations of June 1911 came marked "Confidential"; and in contrast to Nernst's 1910 reference to "hitherto accepted" kinetic theory, the opening sentence noted the challenge facing the principles of "the classical molecular theory and kinetic theory of matter."61 Precirculated papers provided the basis for discussions, which were chaired by Lorentz. Both his contributed paper and his welcoming address contrasted "old theories" and "modern investigations," with his brief address being most pointedand extending the contrast to one between modern studies and classical theory. Lorentz stated that "we have no right to believe that the physical theories of the future will be subsumed under the rules of classical mechanics."62
When the "classical" entered quantum theory it did so particularly through mechanics, but the Solvay conference saw this language extended to meet the matter at hand ever more precisely and clearly. In the process a new use of "classical" was forged, with a more general purchase on the physics of the past. Lorentz's formal contribution, which focused specifically on the application of equipartition to radiation, was the first paper discussed. Its role was to convince the audience of the poverty of the "old theories" before moving on to quantum theory. Revealingly, the reference to "classical" theory that had figured in Lorentz's welcoming remarks was not repeated here. However, in response to a letter Rayleigh had sent to the congress, Nernst spoke directly of "the classical theory of the equipartition of energy," and Jeans also wrote of "the classical theory of Maxwell and Boltzmann."63 These references show that "classical" hadquite suddenlybecome part of the vocabulary with which several key figures considered work in quantum theory. Very likely this built on the use the term had found in relativity, but in explaining this it is even more important to note that the congress papers were precirculatedand that one contribution offered an argument for a new use of the term.


The most significant invocation of the classical occurs in the paper Planck delivered, "The Laws of Heat Radiation and the Hypotheses of the Elementary Quantum of Action." Boltzmann had linked the sociological use of "classical" to a situation in which methods that once seemed as though they might serve a field forever are suddenly found wanting. Planck's opening paragraphs followed something like Boltzmann's recipe. He wrote:

The principles of classical mechanics, fructified and extended by electrodynamics, and especially electron theory, have been so satisfactorily confirmed in all those regions of physics to which they had been applied ... , that it had looked as though even those areas which could only be approached indirectly through statistical forms of consideration would yield to the same principles without essential modification. The development of the kinetic theory of gases seemed to confirm this belief. ...

Today we must say that this hope has proved illusory, and that the framework of classical dynamics appears too narrow, even extended through the Lorentz-Einstein principle of relativity, to grasp those phenomena not directly accessible to our crude senses. The first incontestable proof of this view has come through the striking contradictions opened up between classical theory and observation in the universal laws of the radiation of black bodies.64

By 1911 Planck had embraced the language of the classicaland then quite consciously and deliberately extended it. Neglecting his earlier view that the application of the equipartition theorem to blackbody radiation was simply unjustified, this decision to extend the concept of the classical to statistical mechanics helped make equipartition classical. Given our awareness of the long controversy over the application of the theorem, Planck's move could be regarded as the invention of a traditionor at least as the endorsement of the approach others had advocated as valued and traditional. It brought the cultural value of the term "classical" into association with the field of statistical mechanics and the specific theorem of the equipartition of energy, heightening interest in the new quantum theory. Here, Planck's formulation asserts, we confront not just difficult choices between current theoretical possibilities but critical drama on an epochal stage.
In terms of Planck's own development, this conception clearly built on his personal struggles but at the same time subtly altered his perspective on the nature of his previous work and the theoretical tools available in 1900. In terms of the dynamics of change within the broader physics community, Planck's formulation would help bring discussion of the new statistics onto the stage of worldview changes, while simultaneously shifting the basis of the worldview discussion from the two previous alternatives in which it had most often been framed to a new, more complex footing. In contrast to the mechanical and electromagnetic worldviews, the very openness of the term "classical" allowed Planck to recast the search for secure foundations as a contrast between the eras before and after quantum theory. In terms of the dynamics of change in European culture more generally, Planck's move would help assert both that physics was part of its culture (involved in the struggle between classical traditions and the modern world) and that it could define a new framework for that worldview.


Both the tight organization of the congress and its subsequent public life in print functioned as ideal means for propagating new understandings of what had previously been a rather esoteric field. The conference proceedings were zealously edited (with additional notes from individual contributors) and appeared both in French and in an updated German translation.65 While the physicists present had reached little consensus on the way forward, Planck had helped them reach a common understanding of what the past had involved. No one illustrates this more clearly than Henri Poincaré, new to quantum theory. Responding to Lorentz's paper on equipartition, Poincaré referred to earlier theories. Jotting down his point to pass to the secretaries, Poincaré first wrote "The new theories" before crossing "new" out and inserting "old." As we might by now expect, the German edition took its liberties, translating "anciennes" as "klassischen," to render Poincaré's comment as a whole: "The classical theories applied the Hamiltonian equations without limitation; Lorentz's considerations show they all lead to the same result" (see Figure 3). Indeed, Poincaré reevaluated a great deal as a result of the conference. Soon afterward he wrote in terms that show how revealing his slip of the pen was:

We might ask ourselves if mechanics is on the brink of a revolution. A congress in Brussels recently gathered together about twenty physicists of many nationalities. They were constantly talking about the new mechanics, as opposed to the old mechanicsbut what did they mean by the old mechanics? Newton's, which was still uncontested at the end of the nineteenth century? No, they were referring to Lorentz's mechanics, and the principle of relativity, which scarcely five years ago seemed itself to be the very height of boldness.66

(21 kB)Figure 3. The manuscript of Poincaré's note in Brussels shows that he then thought in terms of "new" and "old" theories ["Les nouvelles anciennes théories"]. The note reads, "The old theories applied the Hamiltonian equations without limitation; Lorentz's considerations show that they all lead to the same result." In the German edition of the conference proceedings, "anciennes" or "old" was translated as "classical," terminology Poincaré himself accepted on other occasions. In Archives de l'Académie des sciences de l'Institut de France, Registre Solvay, Vol. 1 of 2, p. 4.

In this instance Poincaré's astonished language reflects the specific terms in which he had previously contrasted the "old" mechanics with the "new" Lorentzian form. On other occasions his writing shows that he now accepted both the periodization and the terminology Planck had provided (thereby justifying the liberty his translator took). In a major 1912 paper credited with widening the hold of quantum theory in the research community, Poincaré contrasted the new to "classical mechanics," and now (unlike in 1902) he explicitly described the latter as incorporating the Hamiltonian equations.67
IN CONCLUSION I have shown here that paying close attention to invocations of the word "classical" in different contexts offers new perspectives on the thinking of a good handful of turn-of-the-century physicists, revealing, for example, significant shifts in the terms in which individuals like Poincaré and Planck framed their understandings of past and present research. Returning briefly to Boltzmann will help outline several more general findings. First, note that what had been an importantly sociological insight in Boltzmann was now given an epochal understanding in the German physics community, turning on a fulcrum quite different from the original one that Boltzmann had offeredon the turn of the century rather than the success of Maxwell's work. Second, what "classical" meant was ultimately defined not by adherents of the past traditions themselves, as Boltzmann had it, but largely from the perspective of the new theories of relativity and quantum theory. In this, "classical physics" differs importantly from the articulation of the mechanical, energetic, or electromagnetic programs by practitionersa point that will need to be clearly recognized as we develop a more refined understanding of the process by which the new theories were won and defended.
Exploring fin-de-siècle physics has shown that, rather than reflecting consensus views of the past, the earliest general concepts of classical theory were tendentious, deeply implicated in physicists' programs for different futures. The tensions and imperatives originally expressed in different versions of "classical mechanics" and "classical thermodynamics" conditioned the gradual formation of a new concept of past theory but have long been invisible. To put the point rather strongly: one could say that, apart from physicists who were classical by temperament (in Ostwald's sense) or became classical late (like Russell McCormmach's famous night thinker, looking back after World War I), there was only ever one "classical physicist." His name was Ludwig Boltzmann. Even given Boltzmann's voice in the wilderness, we have found that the patina of allegiance to the classical past was far more important to the formation of new theory in the twentieth century than it was to physicists of earlier times. Contemporaries had more often worked with and against theory they regarded as current, Newtonian, or old, defending stances on a continuum from phenomenological to atomistic and articulating distinctions ranging from mechanical through energetic to electromagnetic. Having argued that we should think of Boltzmann as the only truly classical classical physicist, I have also shown that, despite the introduction of Planck's theory of radiation in 1900 and the interplay between classical mechanics and relativity, Max Planck first christened the modern form of classical physics in 1911. The theory of relativity and the Solvay Council set the stage for the later public understanding that the fin de siècle had witnessed the overthrow of classical and the birth of modern physics. And within the physics community the concept of classical physicseven of a classical worldwould now become a potent heuristic foil for the development of a new quantum theory and mechanics of the atom, as Niels Bohr's work soon began to show.

* Department of History of Science, University of WisconsinMadison, 7143 Social Sciences Building, 1180 Observatory Drive, Madison, Wisconsin 53706-1393.
Thanks are due to Otto Sibum and the members of the research group on Experimental History of Science at the Max Planck Institute for the History of Science, Berlin, for the opportunity to finish this essay in an extremely productive intellectual environment. I have benefited in particular from talking through many of the issues raised with Suman Seth. This paper was first given at the Interdisciplinary Seminar on the Fin-de-Siècle at the University of Oxford, 4 December 2003. For their close reading and helpful suggestions I thank the Isis referees, Michel Janssen, Olivier Darrigol, Scott Walter, Lynn Nyhart, and Ed Jurkowitz.

[Lloyd Gillespie]

On the Co-Creation of Classical and Modern Physics [cont...]

Richard Staley*



1 Max Planck to Robert W. Wood, 7 Oct. 1931, Archive for the History of Quantum Physics, Microfilm 66,5; this English version appears in Dieter Hoffmann and Jost Lemmerich, Quantum Theory Centenary, trans. Ann Hentschel (Berlin: Deutsche Physikalische Gesellschaft, Bad Honnef, 2000), pp. 4950.
2 Thomas S. Kuhn, Black-Body Theory and the Quantum Discontinuity, 18941912 (1978; Chicago/London: Univ. Chicago Press, 1987). Several features of Kuhn's work attracted controversy, and a more adequate treatment of Planck has been developed in the work of Needell, Darrigol, and Gearhart. See esp. Allan A. Needell, "Irreversibility and the Failure of Classical Dynamics: Max Planck's Work on the Quantum Theory, 19001915" (Ph.D. diss., Yale Univ., 1980); Needell, "Introduction," in Max Planck, The Theory of Heat Radiation (Los Angeles: Tomash; New York: American Institute of Physics, 1988), pp. xixlv; Olivier Darrigol, From c-Numbers to q-Numbers: The Classical Analogy in the History of Quantum Theory (Berkeley/Los Angeles: Univ. California Press, 1992); Darrigol, "The Historians' Disagreements over the Meaning of Planck's Quantum," Centaurus, 2001, 43:219239; and Clayton A. Gearhart, "Planck, the Quantum, and the Historians," Physics in Perspective, 2002, 4:170215.
3 Planck's key 1900 paper highlighted the simple structure of the formula he had found and its establishment of a logarithmic relationship between the entropy and energy of the ideal oscillators that he used to model the walls of the blackbody. He thought this relationship made his own blackbody radiation law look more promising than any other except Wilhelm Wien's (which has that property but doesn't fit the data): Max Planck, "Zur Theorie des Gesetzes der Energieverteilung im Normalspektrum," Deutsche Physikalische Gesellschaft: Verhandlungen, 1900, 2:237245, on p. 237. See also Kuhn, Black-Body Theory, pp. 110113; and the overview in J. L. Heilbron, The Dilemmas of an Upright Man: Max Planck and the Fortunes of German Science (Cambridge, Mass.: Harvard Univ. Press, 2000), pp. 128.
4 Kuhn pointed to Planck's emphasis on the parallels between his own approach and Boltzmann's; see Kuhn, Black-Body Theory, p. 125. For the critical perspective see Needell, "Introduction" (cit. n. 2), pp. xixliii; and Darrigol, "Historians' Disagreements over the Meaning of Planck's Quantum" (cit. n. 2), p. 224. For the concept in use see Stachel's descriptions of Einstein's work on relativity and quantum theory in Albert Einstein, The Collected Papers of Albert Einstein, Vol. 2: The Swiss Years: Writings, 19001909, ed. John Stachel (Princeton, N.J.: Princeton Univ. Press, 1989), pp. xvii, xxviii, 137. Büttner, Renn, and Schemmel have recently deployed the term epistemologically, without investigating physicists' own understanding. McCormmach's well-known fictional physicist is imagined looking back on his career after World War I, by which time "classical physics" was indeed becoming a highly important category. See Jochen Büttner, Jürgen Renn, and Matthias Schemmel, "Exploring the Limits of Classical Physics: Planck, Einstein, and the Structure of a Scientific Revolution," Studies in the History and Philosophy of Modern Physics, 2003, 34:3759; and Russell McCormmach, Night Thoughts of a Classical Physicist (New York: Avon, 1982).
5 James C. Albisetti, Secondary School Reform in Imperial Germany (Princeton, N.J.: Princeton Univ. Press, 1983).
6 In contrast, Mehrtens has shown that various stances with regard to the category of modern mathematics were central to disciplinary debates in the mathematical community; see Herbert Mehrtens, ModerneSpracheMathematik: Eine Geschichte des Streits um die Grundlagen der Disziplin und des Subjekts formaler Systeme (Frankfurt am Main: Suhrkamp, 1990). A study of uses of the term "modern physics" would show a plurality of invocations in association with specific subjects (such as modern instruments, values, laboratories, studies, etc.). Its use in an epochal sense actually preceded similar treatment of the word "classical"; writers often referred to "modern" science or physics as that since Galileo. We shall see that by the 1911 Solvay Council H. A. Lorentz had paired "classical" and "modern" concepts around turn-of-the-century events.
7 Initially published in 1899, the address was reprinted in 1905 and has been translated into English: Ludwig Boltzmann, "Über die Entwickelung der Methoden der theoretischen Physik in neuerer Zeit," Physikalische Zeitschrift, 1899, 1:6062, 7779, 9298; Boltzmann, "Über die Entwickelung der Methoden der theoretischen Physik in neuerer Zeit," in Populäre Schriften (Leipzig: Barth, 1905), pp. 198227; and Boltzmann, "On the Development of the Methods of Theoretical Physics in Recent Times," in Theoretical Physics and Philosophical Problems: Selected Writings, ed. Brian McGuinness, trans. Paul Foulkes (Vienna Circle Collection) (Dordrecht/Boston: Reidel, 1974), pp. 77100. Here I follow the English translations of Boltzmann's lectures except where noted.
8 General studies of physics circa 1900 include Erwin N. Hiebert, "Fin-de-Siècle Physics," in Rutherford and Physics at the Turn of the Century, ed. Mario Bunge and William R. Shea (New York: Dawson/Science History Publications, 1979), pp. 322; J. L. Heilbron, "Fin-de-Siècle Physics," in Science, Technology, and Society in the Time of Alfred Nobel, ed. Carl Gustaf Bernhard, Elisabeth Crawford, and Per Sörbom (Oxford: Nobel Foundation, 1982), pp. 5173; Theodore M. Porter, "The Death of the Object: Fin de Siècle Philosophy of Physics," in Modernist Impulses in the Human Sciences, 18701930, ed. Dorothy Ross (Baltimore: Johns Hopkins Univ. Press, 1994), pp. 128151; Brian Pippard, "Physics in 1900," in Twentieth Century Physics, ed. Laurie M. Brown, Abraham Pais, and Pippard (Bristol: Institute of Physics Publishing; Philadelphia/New York: American Institute of Physics Press, 1995), pp. 141; and Helge Kragh, Quantum Generations: A History of Physics in the Twentieth Century (Princeton, N.J.: Princeton Univ. Press, 1999), pp. 326.
9 Boltzmann, "Methods of Theoretical Physics" (cit. n. 7), pp. 79, 7980.
10 Klimt's secessionist movement and the convergence of political and cultural dimensions in the debate over the university paintings is discussed in Carl E. Schorske, Fin-de-Siècle Vienna: Politics and Culture (New York: Vintage, 1981), pp. 225245. Boltzmann had already left for Leipzig when Philosophy was unveiled, but the brothers Sigmund and Franz Serafin Exner (professors of physiology and experimental physics at the University of Vienna) engaged in a sustained attack on Klimt's work. See Deborah R. Coen, "A Scientific Dynasty: Probability, Liberalism, and the Exner Family in Imperial Austria" (Ph.D. diss., Harvard Univ., 2004), pp. 178238.
11 Boltzmann, "Methods of Theoretical Physics" (cit. n. 7), pp. 82 (quotation; I have modified the translation slightly), 8385. On Boltzmann's epistemology see Salvo D'Agostino, "Boltzmann and Hertz on the Bild-Conception of Physical Theory," History of Science, 1990, 28:380398, esp. pp. 381384; and Andrew D. Wilson, "Mental Representation and Scientific Knowledge: Boltzmann's `Bild' Theory of Knowledge in Historical Context," Physis: Rivista Internazionale di Storia della Scienza, 1991, 28:769795. Heilbron's interpretation of descriptionism as a modest and defensive mode enabling the physical sciences to avoid antagonizing established values and higher cultural authorities downplays the extent to which it promoted both criticism of previous certainties and a search for unity independent of particular singular foundations. It has been challenged by Porter's focus on the methodological resources descriptionism provided for the development of the social sciences. See Heilbron, "Fin-de-Siècle Physics" (cit. n. 8); and Porter, "Death of the Object" (cit. n. 8).
12 Boltzmann, "Methods of Theoretical Physics," pp. 8890. Boltzmann's mechanics is discussed in Arthur I. Miller, "On the Origins, Methods, and Legacy of Ludwig Boltzmann's Mechanics," in Ludwig Boltzmann, Gesamtausgabe, Vol. 8: Internationale Tagung, 5.8. September 1981: Ausgewählte Abhandlungen, ed. Roman Sexl and John Blackmore (Graz/Braunschweig: Akademische Druck- und Verlagsanstalt/Vieweg, 1982), pp. 231261. The tension between Boltzmann's and Poincaré's early uses of "classical" and later understandings is briefly discussed in Blackmore, ed., Ernst MachA Deeper Look: Documents and New Perspectives (Dordrecht/Boston: Kluwer Academic Publishers, 1992), pp. 119120.
13 Boltzmann, "Methoden der theoretischen Physik in neuerer Zeit" (cit. n. 7), p. 205 (my translation); see also Boltzmann, "Methods of Theoretical Physics," p. 82. It would be a mistake to read Boltzmann's stance as conservative in any simplistic sense.
14 Ludwig Boltzmann, Vorlesungen über die Principe der Mechanik (Leipzig: Barth, 1897), p. v. Boltzmann's book on mechanics provides a concrete exemplification of the position in which he saw himself, in 1899, as a classical physicist, though as we will see in the second section of this essay his view of what was classical in mechanics was in fact controversial.
15 See Gustav Kirchhoff, Vorlesungen über mathematische Physik: Mechanik (Leipzig: Teubner, 1876), "Vorrede"; Ernst Mach, Die Mechanik in ihrer Entwickelung: Historisch-kritisch dargestellt (Leipzig: Brockhaus, 1883), pp. 6, 238; and Heinrich Hertz, Die Prinzipien der Mechanik in neuem Zusammenhange dargestellt (Leipzig: Barth, 1894), p. 5.
16 Georg Helm, The Historical Development of Energetics, trans. Robert J. Deltete (Dordrecht/Boston: Kluwer, 2000), p. 153. Helm wrote of the need to combat the artificial prolongation of the mechanical hypothesis and, especially, its conflation with energetics (pp. 192193).
17 Larmor's star was rising: he became Secretary of the Royal Society in 1901 and inherited Newton's chair in 1903. For studies of Larmor's contributions to electrodynamics see Andrew Warwick, Masters of Theory: Cambridge and the Rise of Mathematical Physics (Chicago/London: Univ. Chicago Press, 2003), Ch. 7; and Olivier Darrigol, "The Electron Theories of Larmor and Lorentz: A Comparative Study," Historical Studies in the Physical and Biological Sciences, 1994, 24:267336.
18 Joseph Larmor, "Address of the President of the Mathematical and Physical Section of the British Association for the Advancement of Science," Science, 1900, 12:417436, on pp. 417, 418, 420; there is a further reference to a classical exposition from Kelvin on p. 428. In Larmor's rendering Maxwell's work had won classical status despite outstanding gaps and difficulties (p. 422).
19 Hermann Helmholtz, Über die Erhaltung der Kraft (Ostwalds Klassiker der exakten Wissenschaften, 1) (Leipzig: Engelmann, 1889). Volume 121, published in 1901, made two of Gregor Mendel's then little-known papers on plant hybridization newly accessible.
20 Larmor, "Address" (cit. n. 18), p. 422.
21 Henri Poincaré, La science et l'hypothèse (Paris: Flammarion, 1902); Poincaré, Wissenschaft und Hypothese, trans. by F. and L. Lindemann (Leipzig: Teubner, 1904); and Poincaré, Science and Hypothesis, trans. William John Greenstreet (London: Scott, 1905). The German edition, edited by Ferdinand Lindemann and translated by his wife, included lengthy footnotes extending and updating many facets of Poincaré's discussion. On Poincaré's contributions to electrodynamics see esp., in addition to the works cited below, Olivier Darrigol, "Henri Poincaré's Criticism of Fin de Siècle Electrodynamics," Stud. Hist. Phil. Mod. Phys., 1995, 26:144.
22 An earlier version of this chapter was presented at the International Congress on Philosophy in Paris in 1900. Miller has highlighted the broad cultural significance of Poincaré's book with his argument that both Picasso and Einstein responded to Poincaré's focus on simultaneity by finding new ways to represent simultaneity in space and time (respectively), thereby developing radical new approaches to their fields. See Arthur I. Miller, Einstein, Picasso: Space, Time, and the Beauty That Causes Havoc (New York: Basic, 2001).
23 Peter Galison, Einstein's Clocks, Poincaré's Maps: Empires of Time (New York/London: Norton, 2003). For a nuanced interpretation of Poincaré's use of the term in mathematical and physical contexts see Elie Zahar, Poincaré's Philosophy: From Conventionalism to Phenomenology (Chicago/La Salle, Ill.: Open Court, 2001).
24 Poincaré, Science and Hypothesis (cit. n. 21), pp. 97110. Poincaré writes "La mécanique classique" in the original; see Poincaré, Science et l'hypothèse (cit. n. 21), pp. 111128. Andrade himself had contrasted the "classical school [l'École classique]" with the thread or relational school; see Jules Frédéric Charles Andrade, Leçons de mécanique physique (Paris: Société d'Éditions Scientifiques, 1898), pp. 135144. See also the discussion in René Dugas, A History of Mechanics, trans. J. R. Maddox (Neuchâtel: Éditions du Griffon; New York: Central Book, 1955), pp. 434458.
25 The discussion occurs in Poincaré, Science and Hypothesis, Ch. 8: "Energy and Thermodynamics," pp. 123124, 128. In the original French the latter two references are to "la théorie classique" and "système classique": Poincaré, Science et l'hypothèse, pp. 139140, 143.
26 Poincaré, Science and Hypothesis, p. 124; and Poincaré, Science et l'hypothèse, p. 140. Zahar discusses the reasons for Poincaré's distinctions between Newton's theory and Hamilton's equations in Elie Zahar, "Poincaré's Structural Realism and His Logic of Discovery," in Science et philosophie/Science and Philosophy/Wissenschaft und Philosophie, ed. Jean-Louis Greffe, Gerhard Heinzmann, and Kuno Lorenz (Berlin: Akademie Verlag; Paris: Blanchard, 1996), pp. 4568, on p. 58. Distinctions of this kind reflect Poincaré's readiness to teach structurally equivalent formulations for methodological and philosophical reasons. It would be a mistake to extrapolate too far from Poincaré's usage in this context, and we shall see that he later accepted an extended reading of "classical mechanics" that incorporated the Hamiltonian formulation; but it is just as significant to note that he did not originally use the term that generally himself.
27 Chs. 913 offered Poincaré's perspective on recent physics.
28 There is, however, one more reference to "classic" to note: in the final chapter of the book he applies the word once to a second field, writing of the classic system of electrodynamics that "is perhaps even now not quite definitive" (referring to Lorentz's development of Maxwell's theory). Poincaré, Science and Hypothesis, p. 225; and Poincaré, Science et l'hypothèse, p. 227. Poincaré offered a second overview in 1904, describing physics as having entered on a second great phase (with Maxwell's work offering its most remarkable example). In contrast to the earlier mathematical physics of central forces, he saw the present phase as one of the mathematical physics of principles. Poincaré focuses even more clearly on the questionable status of guiding principles, speculating on kinetic theory or a new mechanics as potential avenues toward a third form of physics. See Henri Poincaré, "The Principles of Mathematical Physics" (1905), in Physics for a New Century: Papers Presented at the 1904 St. Louis Congress, ed. Katherine R. Sopka and Albert E. Moyer (Los Angeles: Tomash; New York: American Institute of Physics, 1986), pp. 281299; this article was originally published as Poincaré, "L'état actuel et l'avenir de la physique mathématique," Bulletin des Sciences Mathématiques, 1904, 28:302324.
29 Paul Forman focused on such sources in his important study "Weimar Culture, Causality, and Quantum Theory, 19181927: Adaptation by German Physicists and Mathematicians to a Hostile Intellectual Environment," Historical Studies in the Physical Sciences, 1971, 3:1116.
30 Poincaré, Wissenschaft und Hypothese (cit. n. 21), p. iii. Larmor did contrast "the close-knit theories of the classical French mathematical physicists" with the "somewhat loosely-connected corpus of ideas with which Maxwell ... has (posthumously) recast the whole face of physical science." Poincaré wrote, rather, of the "old theories of mathematical physics [les anciennes theories de la physique mathématique]": Joseph Larmor, "Introduction," in Poincaré, Science and Hypothesis (cit. n. 21), pp. xixvii, on p. xiv. See also Poincaré, Science and Hypothesis, p. 213; and Poincaré, Science et l'hypothèse, p. 217.
31 Russell McCormmach, "H. A. Lorentz and the Electromagnetic View of Nature," Isis, 1970, 61:459497. For an overview see Christa Jungnickel and McCormmach, Intellectual Mastery of Nature: Theoretical Physics from Ohm to Einstein, 2 vols., Vol. 2: The Now Mighty Theoretical Physics, 18701925 (Chicago/London: Univ. Chicago Press, 1986), pp. 211253.
32 Wien's remark came in discussion of Lorentz's contribution to the German Naturforscherversammlung in 1900: H. A. Lorentz, "Über die scheinbare Masse der Ionen," Phys. Z., 1900, 2:7880, on pp. 7980. Boltzmann was one of many who took notice of the electromagnetic program, tracking the rise of the new approach and endorsing it as a viable alternative in the second part of his lectures on mechanics in 1904: Ludwig Boltzmann, "On the Principles of Mechanics, I, II" (1900, 1902), in Theoretical Physics and Philosophical Problems, ed. McGuinness (cit. n. 7), pp. 129152. See also Boltzmann, Vorlesungen über die Principe der Mechanik, Vol. 2 (Leipzig: Barth, 1904), pp. 138139.
33 Paul Arthur Schilpp, ed., Albert Einstein: Autobiographical Notes: A Centennial Edition (La Salle, Ill.: Open Court, 1979), pp. 4445 (Einstein's account is pervaded by a retrospective treatment of "classical physics"); and Jürgen Renn, "Einstein's Controversy with Drude and the Origin of Statistical Mechanics: A New Glimpse from the `Love Letters,'" in Einstein: The Formative Years, 18791909, ed. Don Howard and John Stachel (Boston/Basel: Birkhäuser, 2000), pp. 107157.
34 Darrigol discusses Poincaré's important critical approach to principles in "Poincaré's Criticism of Fin de Siècle Electrodynamics" (cit. n. 21), pp. 1023. For an excellent overview of Einstein's path to relativity see John Stachel, "Einstein on the Theory of Relativity," in Collected Papers of Albert Einstein, Vol. 2, ed. Stachel (cit. n. 4), pp. 253274; rpt. in Stachel, Einstein from "B" to "Z" (Einstein Studies, 9) (Boston/Basel: Birkhäuser, 2002), pp. 191214. On the relations between Poincaré and Einstein see Olivier Darrigol, "The Mystery of the EinsteinPoincaré Connection," Isis, 2004, 95:614626.
35 Poincaré, "Principles of Mathematical Physics" (cit. n. 28), p. 298. Note that on this occasion the word "classical" did not enter his discussion. See also note 32, above. Voss discussed the implications of the electrical worldview in a 1901 survey of rational mechanics, and, importantly, Max Abraham wrote of exploiting analogies between the principles of the dynamics of the electron and the principles of the ordinary dynamics of material bodies in developing a future electromagnetic foundation for the whole of mechanics. See Aurel Voss, "Die Prinzipien der rationellen Mechanik," in Encyclopädie der mathematischen Wissenschaft, ed. Felix Klein and Conrad Müller (Leipzig: Teubner, 1901), pp. 3121, on p. 40; and Max Abraham, "Prinzipien der Dynamik des Elektrons," Phys. Z., 1903, 4:5763, on p. 57.
36 Albert Einstein to Conrad Habicht, 18 or 25 May 1905, in Einstein, The Collected Papers of Albert Einstein, Vol. 5: The Swiss Years: Correspondence, 19021914, ed. Martin J. Klein, A. J. Kox, and Robert Schulmann (Princeton, N.J.: Princeton Univ. Press, 1993), doc. 27.
37 Albert Einstein, "Zur Elektrodynamik bewegter Körper," Annalen der Physik, 1905, 17:891921, on pp. 891892. Translations from Einstein's papers are my own; serviceable English translations are accessible in Albert Einstein, The Collected Papers of Albert Einstein, Vol. 2: The Swiss Years: Writings, 19001909, trans. Anna Beck (Princeton, N.J.: Princeton Univ. Press, 1989). For Planck's response see Max Planck, "Das Prinzip der Relativität und die Grundgleichungen der Mechanik," Deut. Phys. Gesell. Verhandl., 1906, 8:136141, on pp. 137, 140. See also Planck, "Zur Dynamik bewegter Systeme," Ann. Phys., 1908, 26:134; Planck, "Zur Dynamik bewegte Systeme," Königliche Preussische Akademie der Wissenschaften (Berlin): Sitzungsberichte, 1907, 29:542570; and Planck, "Bemerkungen zum Prinzip der Aktion und Reaktion der allgemeinen Dynamik," Deut. Phys. Gesell. Verhandl., 1908, 10:728732. On Planck see Stanley Goldberg, "Max Planck's Philosophy of Nature and His Elaboration of the Special Theory of Relativity," Hist. Stud. Phys. Sci., 1976, 7:125160. For a study of the early development of relativity see Richard Staley, "On the Histories of Relativity: The Propagation and Elaboration of Relativity Theory in Participant Histories in Germany, 19051911," Isis, 1998, 89:263299.
38 Albert Einstein, "Über das Relativitätsprinzip und die aus demselben gezogene Folgerungen," Jahrbuch der Radioaktivität und Elektronik, 1907, 4:411462, on pp. 433436 (on force), 414.

[Lloyd Gillespie]

On the Co-Creation of Classical and Modern Physics [cont...]

Richard Staley*


ABSTRACT
While the concept of "classical physics" has long framed our understanding of the environment from which modern physics emerged, it has consistently been read back into a period in which the physicists concerned initially considered their work in quite other terms. This essay explores the shifting currency of the rich cultural image of the classical/modern divide by tracing empirically different uses of "classical" within the physics community from the 1890s to 1911. A study of fin-de-siècle addresses shows that the earliest general uses of the concept proved controversial. Our present understanding of the term was in large part shaped by its incorporation (in different ways) within the emerging theories of relativity and quantum theorywhere the content of "classical" physics was defined by proponents of the new. Studying the diverse ways in which Boltzmann, Larmor, Poincaré, Einstein, Minkowski, and Planck invoked the term "classical" will help clarify the critical relations between physicists' research programs and their use of worldview arguments in fashioning modern physics.
39 He describes the suggestion as widespread: Hermann Minkowski, "Die Grundgleichungen für die elektromagnetischen Vorgänge in bewegten Körpern," Königliche Gesellschaft der Wissenschaften zu Göttingen: Mathematisch-Physikalische Klasse: Nachrichten, 1908, pp. 53111; the topic is forecast on p. 56 and treated in an appendix on pp. 98111. Poincaré and Einstein may both provide sources for Minkowski's use of the term "classical," which as far as I can see was not as widely used as his comment suggests. It is possible that Minkowski subsumed others' references to the "old" or "ordinary" mechanics within his understanding of "classical." On Minkowski see Leo Corry, "Hermann Minkowski and the Postulate of Relativity," Archive for History of Exact Sciences, 1997, 51:273314; Scott Walter, "Minkowski, Mathematicians, and the Mathematical Theory of Relativity," in The Expanding Worlds of General Relativity, ed. Hubert Goenner et al. (Boston: Birkhäuser, 1999), pp. 4586; Walter, "Breaking in the 4-Vectors: The Four-Dimensional Movement in Gravitation, 19051910," in The Genesis of General Relativity, Vol. 3: Theories of Gravitation in the Twilight of Classical Physics, Pt. 1, ed. Jürgen Renn and Matthias Schemmel (Dordrecht: Kluwer, forthcoming); and Peter L. Galison, "Minkowski's Space-Time: From Visual Thinking to the Absolute World," Hist. Stud. Phys. Sci., 1979, 10:85121.
40 Minkowski, "Die Grundgleichungen für die elektromagnetischen Vorgänge in bewegten Körpern," p. 99; and Hermann Minkowski, "Raum und Zeit," Phys. Z., 1909, 10:104111, rpt. in H. A. Lorentz et al., Das Relativitätsprinzip: Eine Sammlung von Abhandlungen (1913), 7th ed. (Leipzig/Berlin: Teubner, 1974).
41 Paul Volkmann, Einfuhrung in das Studium der theoretischen Physik, insbesondere in das der analytischen Mechanik mit einer Einleitung in die Theorie der physikalischen Erkenntniss: Vorlesungen (Leipzig: Teubner, 1900); and Voss, "Prinzipien der rationellen Mechanik" (cit. n. 35), p. 49. Volkmann cited Lagrangian mechanics in particular and referred in preference to the "customary" or "ordinary" mechanics. See also Volkmann, "Die gewöhnliche Darstellung der Mechanik und ihre Kritik durch Hertz," Zeitschrift für den Physikalischen und Chemischen Unterricht, 1901, 14:266283.
42 Born explicitly sought to use the analogy between the old and the new to develop relativistic analogues to concepts important in the customary kinematics, without complete success. Max Born, "Die Theorie des starren Elektrons in der Kinematik des Relativitätsprinzip," Ann. Phys., 1909, 30:156.
43 Ostwald reworked the traditional language of temperaments within a binary framework, describing the classical type as likely to exhibit phlegmatic and melancholic rather than sanguine and choleric features. See Wilhelm Ostwald, Grosse Männer: Studien zur Biologie des Genies (Leipzig: Akademische Verlagsgesellschaft, 1909), pp. 371388. See also McCormmach, Night Thoughts of a Classical Physicist (cit. n. 4), pp. 5354.
44 Max Planck, Acht Vorlesungen über theoretische Physik gehalten an der Columbia University in the City of New York im Frühjahr 1909 (Leipzig: Hirzel, 1910), pp. 78. Planck showed no such self-consciousness in describing Lorentz's studies as "classic" on pp. 89.
45 Max Laue, Das Relativitätsprinzip (Braunschweig: Vieweg, 1911) (in effect he followed the same structure Einstein had used in his 1907 research review); Ludwig Silberstein, The Theory of Relativity (London: Macmillan, 1914); and Ebenezer Cunningham, The Principle of Relativity (Cambridge: Cambridge Univ. Press, 1914). On English attitudes to the development of relativity theory in Germany see Warwick, Masters of Theory (cit. n. 17), Ch. 8.
46 Einstein's development of general relativity did not change this typical argumentative structure in either research or popular contexts, with the "classical" principle of relativity preceding discussions of the generalizations required for the special and general theories. See, e.g., Albert Einstein, "Die Grundlage der allgemeinen Relativitätstheorie" (1916), in Lorentz et al., Das Relativitätsprinzip (cit. n. 40), pp. 81124; and Einstein, Über die spezielle und die allgemeine Relativitätstheorie: Gemeinverständlich (Braunschweig: Vieweg, 1917).
47 Max Planck, "Die Einheit des physikalischen Weltbildes," Phys. Z., 1909, 10:6275, on pp. 64, 68. See also Albert Einstein, "Über die vom Relativitätsprinzip geforderte Trägheit der Energie," Ann. Phys., 1907, 23:371384, on pp. 371372.
48 Each component or mode of a system that is capable of independent motion constitutes a degree of freedom. For example, a material point has three degrees of freedom corresponding to its three independent translational motions. An atom with extended structure should have at least six, with three possible independent rotations in addition to translational motion. Each degree of freedom will possess an average energy of 1/2kT, where k is Boltzmann's constant and T is the absolute temperature. In general, measurements of specific heats indicated fewer degrees of freedom than expected, while the multitude of spectral lines suggested that molecules must have considerable complexity, with far more than six variables.
49 Lord Kelvin, "Nineteenth Century Clouds over the Dynamical Theory of Heat and Light," in The Royal Institution Library of Science: Physical Sciences, ed. W. L. Bragg and G. Porter (Barking, Essex/Amsterdam: Elsevier, 1970), pp. 324358, on pp. 329, 333, 358. His discussion of equipartition extends over almost thirty pages: pp. 329358. The paper was printed as an appendix in his Baltimore Lectures on Molecular Dynamics and the Wave Theory of Light (London: Clay, 1904). Brush discusses debate on the equipartition theorem in Stephen G. Brush, The Kind of Motion We Call Heat: A History of the Kinetic Theory of Gases in the Nineteenth Century, Vol. 2: Statistical Physics and Irreversible Processes (Amsterdam/New York: North-Holland, 1976), pp. 356363. Klein emphasized the profile of equipartition and Planck's wary engagement with statistical mechanics in explaining his lack of reference to it in 1900; see Martin J. Klein, "Max Planck and the Beginning of the Quantum Theory," Arch. Hist. Exact Sci., 1962, 1:459479.
50 Carl Barus, "The Progress of Physics in the Nineteenth Century," Science, 1905, 22:353369, 385397, on pp. 353, 355 (commanding importance), 355, 368, 387, 388 (for uses of "classic"), 364365 (kinetic theory), 365 (blackbody). Initially delivered at the International Congress of Physics in St. Louis, the paper has been reprinted in Sopka and Moyer, eds., Physics for a New Century (cit. n. 28), pp. 107143. "Modern" was used quite generally to describe the physics of the present era rather than more recent physics alone (p. 353). Describing each of the five main divisions of dynamics, acoustics, heat, light, and electricity as having its own "sublime classics" (p. 355), Barus wrote that until a cataclysm in the history of thought ushered in a new era it would not be possible to discriminate between the independent, parallel lines of investigation along which physics was making such vigorous if partial progress (p. 353).
51 He stated that equipartition failed in general, "for some reason not yet explained": Lord Rayleigh, "Remarks upon the Law of Complete Radiation," Philosophical Magazine, 1900, 49:539540.
52 This point has not yet been recognized in accounts that describe the equipartition theorem as being founded in classical physics or Einstein's paper as showing that light quanta could not be explained "on the basis of either Maxwell's theory or classical mechanics." The latter formulation relies on describing statistical mechanics as an extension of classical mechanics. Although Boltzmann would have urged this, I do not know of any case before 1911 in which contemporaries used such an extended understanding. See Collected Papers of Albert Einstein, Vol. 2, ed. Stachel (cit. n. 4), pp. xvii (quotation), xxviii, 137. Regarding the controversial status of the equipartition theory see, e.g., the discussions of Klein and Brush referred to in note 49.
53 In the first paper Einstein argued that, if confirmed empirically, his studies would show that "classical thermodynamics" could not be regarded as strictly valid for microscopically visible motions. In the second he described "classical thermodynamics" as distinguishing in principle between heat and other forms of energy (in contrast to the molecular theory of heat). Albert Einstein, "Über die von der molekularkinetischen Theorie der Wärme geforderte Bewegung von in ruhenden Flüssigkeiten suspendierten Teilchen," Ann. Phys., 1905, 17:549560, on p. 549; and Einstein, "Zur Theorie der Brownschen Bewegung," ibid., 1906, 19:371381, on p. 372. In a fascinating letter describing his attitude toward the need for elementary foundations in physics, Einstein also compared relativity as it stoodwithout a more elementary understanding of electrical and magnetic processesto classical thermodynamics before Boltzmann's probabilistic interpretation of entropy. See Einstein to Arnold Sommerfeld, 14 Jan. 1908, in Collected Papers of Albert Einstein, Vol. 5, ed. Klein et al. (cit. n. 36), doc. 73. For the 1909 paper see Einstein, "Zum gegenwärtigen Stand des Strahlungsproblems," Phys. Z., 1909, 10:185193, on p. 187.
54 See J. H. Jeans, "The Dynamical Theory of Gases," Nature, 1905, 71:607. Jeans developed his approach in discussion with Rayleigh. See Lord Rayleigh, "The Dynamical Theory of Gases and of Radiation," ibid., 1905, 72:5455; Jeans, "On the Partition of Energy between Matter and Aether," Phil. Mag., 1905, 10:9198; and Rayleigh, "The Constant of Radiation as Calculated from Molecular Data," Nature, 1905, 72:243244. On the nontraditional nature of Jeans's approach to kinetic theory see G. H. Bryan, "Three Cambridge Mathematical Works" [book review], ibid., 1905, 71:601603; and Max Planck, Vorlesungen über die Theorie der Wärmestrahlung (Leipzig: Barth, 1906), pp. 177178. Recent studies of Jeans make essential use of an anachronistic concept of the classical, although Hudson has recognized difficulties in the practice. See Rob Hudson, "James Jeans and Radiation Theory," Studies in History and Philosophy of Science, 1989, 20:5776; Geoffrey Gorham, "Planck's Principle and Jeans's Conversion," ibid., 1991, 22:471497; and Hudson, "Classical Physics and Early Quantum Theory: A Legitimate Case of Theoretical Underdetermination," Synthese, 1997, 110:217256.
55 Jeans regarded Planck as having followed the methods of statistical mechanics only incompletely, in his avoidance of the implications of the equipartition theorem. See J. H. Jeans, "A Comparison between Two Theories of Radiation," Nature, 1905, 72:293294; and Jeans, "On Non-Newtonian Mechanical Systems, and Planck's Theory of Radiation," Phil. Mag., 1910, 20:943954, on p. 943.
56 Albert Einstein, "Über einen die Erzeugung und Verwandlung des Lichtes betreffenden heuristischen Gesichtspunkt," Ann. Phys., 1905, 17:132148, on pp. 132, 136137; Einstein, "Zur Theorie der Lichterzeugung und Lichtabsorption," ibid., 1906, 20:199206, on pp. 199200; Einstein, "Die Plancksche Theorie der Strahlung und die Theorie der spezifischen Wärme," ibid., 1907, 22:180190, on pp. 183184; Paul Ehrenfest, "Über die physikalische Voraussetzungen der Planck'schen Theorie der irreversiblen Strahlungsvorgänge," Kaiserliche Akademie der Wissenschaften (Vienna): Mathematisch-Naturwissenschaftliche Klasse: Zweite Abtheilung: Sitzungsberichte, 1905, 114:13011314; and Ehrenfest, "Zur Planckschen Strahlungstheorie," Phys. Z., 1906, 7:528532. On Ehrenfest see Martin J. Klein, Paul Ehrenfest, Vol. 1: The Making of a Theoretical Physicist (Amsterdam: North Holland, 1970).
57 Planck, Vorlesungen über die Theorie der Wärmestrahlung (cit. n. 54), p. 178. Gearhart discusses Planck's knowledge of and attitude toward equipartition from 1900 onward in Gearhart, "Planck, the Quantum, and the Historians" (cit. n. 2), pp. 190193.
58 H. A. Lorentz, "Le partage de l'énergie entre la matière pondérable et l'éther" (1908), in Collected Papers (The Hague: Nijhoff, 1934), pp. 317343; O. Lummer and E. Pringsheim, "Über die Jeans-Lorentzsche Strahlungsformel," Phys. Z., 1908, 9:449450; Lorentz, "Zur Strahlungstheorie," ibid., 1908, 9:562; Walther Nernst, F. Koref, and F. A. Lindemann, "Untersuchungen über die spezifische Wärme bei tiefen Temperaturen, I," Königl. Preuss. Akad. Wiss., 1910, 1:247261; Nernst, "Untersuchungen über die spezifische Wärme bei tiefen Temperaturen, II," ibid., pp. 262282; and Nernst, "Untersuchungen über die spezifische Wärme bei tiefen Temperaturen, III," ibid., 1911, 1:306315. See Kuhn, Black-Body Theory (cit. n. 2), Chs. 8, 9.
59 Albert Einstein, "Über die Entwicklung unserer Anschauungen über das Wesen und die Konstitution der Strahlung," Phys. Z., 1909, 10:817826; J. Larmor, "Bakerian Lecture: On the Statistical and Thermodynamical Relations of Radiant Energy," Proceedings of the Royal Society of London: Series A, 1909, 83:8295, on p. 85; Planck, Acht Vorlesungen über theoretische Physik (cit. n. 44), p. 95; and H. A. Lorentz, "Alte und neue Fragen der Physik," Phys. Z., 1910, 11:12341257.
60 Nernst referred to previous [bisherige] theory on two occasions and described the changes concerned as an "umwälzenden Neugestaltung" and "weitgehende Reformation": Walther Nernst to Ernest Solvay, 26 July 1910, as cited in Kuhn, Black-Body Theory (cit. n. 2), pp. 215, 310311 n 25; and Diana Kormos Barkan, "The Witches' Sabbath: The First International Solvay Congress in Physics," Science in Context, 1993, 6:5982, on pp. 7071 (this article was part of a special issue, Einstein in Context, edited by Mara Beller and Jürgen Renn). For Planck's caution see Planck to Nernst, 11 June 1910, quoted in Armin Hermann, The Genesis of Quantum Theory, 18991913, trans. Claude W. Nash (Cambridge, Mass./London: MIT Press, 1971), pp. 136137.
61 Solvay to Paul Langevin, 15 June 1911, Paul Langevin Papers, L8/01, Ecole Supérieure de Physique et de Chimie Industrielles de la Ville de Paris. The letter was addressed from Brussels but asked that replies be sent to Nernst in Berlin. "Confidentielle" is handwritten on the first page of the invitation, and the opening sentence reads, "Selon toutes apparences, nous nous trouvons en ce moment au milieu d'une évolution nouvelle des principes sur lesquels était basée la théorie classique moléculaire et cinétique de la matière." Participants were asked not to speak of the conference before it took place, in order to enhance the discussions when they occurred.
62 "Ansprache von H. A. Lorentz," in Die Theorie der Strahlung und der Quante: Verhandlungen auf einer von E. Solvay einberufenen Zusammenkunft (30. Oktober bis 3. November 1911), ed. A. Eucken (Berlin: Verlag Chemie, 1913), pp. 57, on pp. 56. I will cite the German edition of the conference proceedings, which were originally published as Paul Langevin and M. de Broglie, eds., La théorie du rayonnement et les quanta: Rapports et discussions de la réunion tenue à Bruxelles, du 30 Octobre au 3 Novembre 1911 (Paris: Gauthier-Villars, 1912).
63 H. A. Lorentz, "Die Anwendung des Satzes von der gleichmäßigen Energieverteilung auf die Strahlung," in Theorie der Strahlung, ed. Eucken, pp. 1040, on p. 11; ibid., p. 43 (Nernst's response to Rayleigh's letter); and J. H. Jeans, "Die kinetische Theorie der spezifischen Wärme nach Maxwell und Boltzmann," ibid., pp. 4564, on p. 59 (see also p. 56).
64 Max Planck, "Die Gesetze der Wärmestrahlung und die Hypothese der elementaren Wirkungsquanten," ibid., pp. 7794, on p. 77.
65 I have already cited both the French and German publications (see note 62, above). James Jeans later led a discussion on radiation at the British Association: "Discussion on Radiation," Reports of the British Association for the Advancement of Science, 1913, pp. 376386. See also J. H. Jeans, Report on Radiation and Quantum-Theory (London: Electrician, 1914).
66 Eucken, ed., Theorie der Strahlung, p. 35 (Poincaré's comment); and Henri Poincaré, "L'hypothèse des quanta" (1912), in Oeuvres de Henri Poincaré (Paris: Gauthier-Villars, 1954), pp. 654668, on p. 654.
67 Henri Poincaré, "Sur la théorie des quanta" (1912), in Oeuvres de Henri Poincaré, pp. 626653, on pp. 626, 628629. For the earlier use of "old" and "new" see, e.g., Poincaré, Die neue Mechanik: Vortrag gehalten von Henri Poincaré am 13. Oktober 1910 im "Wissenschaftlicher Verein" zu Berlin (Berlin: Bernstein, 1910). On Poincaré's participation in Brussels and response to quantum theory see Russell McCormmach, "Henri Poincaré and the Quantum Theory," Isis, 1967, 58:3755.