Einstein's Clocks and Poincare's Maps

by Peter Galison

  My hope in exploring clock coordination has been to set Poincaré’s and Einstein’s place within a universe of actions that crossed mechanisms and metaphysics, that made abstract concreteness or, if you will, concrete abstractions. More generally, perhaps we can begin to look at science in a way that avoids two equally problematic positions on the relation of things to thoughts. On one side, there is a long tradition of what could be described as a reductive materialism, the view that demotes ideas, symbols, and values to surface ripples on a deeper current of objects. Through those empiricist glasses of the 1920s through the 1950s, theoretical physics and its philosophy often seemed a provisional addition, not the bulwark of science. Einstein (on this view) appeared as having taken the last, inexorable step in an inductive process that gradually drove out the ether and the absolutes of space and time. Earth’s motion through the ether could not be detected to an accuracy better than the ratio of earth’s velocity to the speed of light (v/c, that is, about one part in ten thousand). Later such measurements improved, showing no evidence of motion to a much higher accuracy (second order in v/c, or about one part in a hundred million), and therefore, so the argument went, Einstein concluded that the ether was “superfluous.”25 No doubt there is much to be said for this experiment-grounded Einstein. His fascination with the detailed conduct of experiments and his gyrocompass work at the Physikalisch-Technische Reichsanstalt reveal a theorist with a clear sense of laboratory procedure and the operation of machines. On the empiricist view, things structured thoughts.

  On the flip side was the antipositivist movement popular in the 1960s and 1970s. Thoughts structured things. Antipositivists aimed to reverse the older generation’s epistemic order; they saw programmes, paradigms, and conceptual schemes as coming first, and they held these to have completely reshaped experiments and instruments. Einstein on the antipositivist screen appeared as the philosophical innovator who dispensed with the material world altogether in a sustained drive for symmetry, principles, and operational definitions. There is much truth here too—reading history with antipositivist glasses exposes those moments when Einstein was chary of experimental results, dubious, for example, of supposed laboratory refutations of special relativity and of astronomical observations that claimed to threaten the general theory.

  Granting both ways of reading history their due, I do not mean to split the difference. Instead, attending to moments of critical opalescence offers a way out of this endless oscillation between thinking of history as ultimately about ideas or fundamentally about material objects. Clocks, maps, telegraphs, steam engines, computers all raise questions that refuse a sterile either/or dichotomy of things versus thoughts.26 In each instance, problems of physics, philosophy, and technology cross. Staring through the metaphorical we can find the literal; through the literal we can see the metaphorical.

  When Einstein came to the Bern patent office in 1902, he entered an institution in which the triumph of the electrical over the mechanical was already symbolically wired to dreams of modernity. Here clock coordination was a practical problem (trains, troops, and telegraphs) demanding workable, patentable solutions in exactly his area of greatest professional concern: precision electromechanical instrumentation. The patent office was anything but the lonely deep-sea lightboat that the no longer young Einstein had longed for as he spoke to the Albert Hall audience in the dark days of October 1933. Reviewing one patent drawing after another in the Bern office, Einstein had a grandstand seat for the great march of modern technologies. And as coordinated clocks were paraded by, they were not traveling alone. The network of electrical chrono-coordination provided political, cultural, and technical unity all at once. Einstein seized on this new, conventional, world-spanning simultaneity machine and installed it at the principled beginning of his new physics. In a certain sense he completed the grand time coordination project of the nineteenth century by designing a new, vastly more general time machine valid everywhere and for all imaginable constantly moving frames of reference within the Universe. But by eliminating the master clock and redefining conventionally defined time to a starting point, Einstein came to be seen by both physicists and the public as having changed their world.

  Poincaré, at the end of his life, co-authored a book entitled What Books Say, What Things Say. This quirky volume combined the endeavors of the two great academies to which he belonged: the literary Académie Française and the scientific Académie des Sciences. From the literary side came articles on the heros of culture, including Hugo, Voltaire, and Bossuet. Poincaré himself contributed chapters on stars, gravity, and heat, but also on coal mining, batteries, and dynamos. Living as easily among philosophers as among mathematicians and engineers, Poincaré’s scholarship, including his work on simultaneity, stood central to all these cultures.

  Einstein’s stance toward the great academies of science was different. Just after World War I, Arthur Eddington, the British astrophysicist, took advantage of a total eclipse to measure the deflection of starlight by the gravitational pull of the sun (or as Einstein would have it, by the sun’s bending of spacetime). Thrust into front-page fame by the resulting confirmation of his general theory of relativity, Einstein overnight became a world figure. Facing the limelight in his increasingly public role, his relativity work after 1919 moved toward the abstract unification of physical forces and away from the machine culture of the patent office. A few days after his 1933 speech in Royal Albert Hall, Einstein left for the United States, where he embraced a venerated if monastic existence at the Institute for Advanced Study in Princeton. Half seer, half mascot, he spoke in oracular terms on everything from the meaning of God to the future of nuclear warfare. In April 1953, two years before his death, Einstein wrote from Princeton to Maurice Solovine of the laughter and insight of their so-unacademic academy during Einstein’s Bern years, when patents, physics, and philosophy stood side by side:

  To the immortal Olympia academy,

  In your short active existence you took a childish delight in all that was clear and reasonable. Your members created you to amuse themselves at the expense of your big sisters who were older and puffed up with pride. I learned fully to appreciate just how far [the members had through you] hit upon the true through careful observations lasting for many long years.

  We three members, all of us at least remained steadfast. Though somewhat decrepit, we still follow the solitary path of our life by your pure and inspiring light; for you did not grow old and shapeless along with your members like a plant that goes to seed. To you I swear fidelity and devotion until my last learned breath! From one who hereafter will be only a corresponding member, A.E.27

  As each struggled with time, philosophy, and relativity at the turn of the century, Poincaré inhabited the Parisian académies of arts and sciences, Einstein the Olympia (non-) Academy. On 15 March 1955, Michele Besso died. It was with Besso that Einstein had so productively spoken in the weeks and months before he came upon the coordination of clocks as the key to finishing his work on special relativity. Einstein wrote to Besso’s family on the twenty-first, closing his letter with a final reference to those conversations, and to the perspectival nature of time that emerged from relativity: “. . . it was the Patent Office that reunited us [after Zurich]. Our conversations on the way home had an incomparable charm; it was if the all-too-human did not exist at all. . . . Now he has also taken leave of this strange world a little before me. This means nothing. For us devout physicists, the division between past, present, and future is only an illusion, if a stubborn one.”28

  Long after Einstein’s own last learned breath, the struggle continued among many competing interpretations of the regulated coordination of clocks. Synchronized time remained hypersymbolized. Einheitszeit never emerged from contestation among imperial empire, democracy, world citizenship, and antianarchism. What all these symbols held in common was a sense that each clock signified the individual, so that clock coordination came to stand in for a logic of linkage among people and
peoples that was always flickering between the literal and the metaphorical. Precisely because it was abstract-concrete (or concretely abstract), the project of time coordination for towns, regions, countries, and eventually the globe became one of the defining structures of modernity. The synchrony of clocks remains an inextricable mix of social history, cultural history, and intellectual history; technics, philosophy, physics.

  Over the last thirty years it has become a commonplace to pit bottom-up against top-down explanations. Neither will do in accounting for time. A medieval saying aimed at capturing the links between alchemy and astronomy put it this way: In looking down, we see up; in looking up, we see down. That vision of knowledge serves us well. For in looking down (to the electromagnetically regulated clock networks), we see up: to images of empire, metaphysics, and civil society. In looking up (to the philosophy of Einstein and Poincaré’s procedural concepts of time, space, and simultaneity) we see down: to the wires, gears, and pulses passing through the Bern patent office and the Paris Bureau of Longitude. We find metaphysics in machines, and machines in metaphysics. Modernity, just in time.

  NOTES

  CHAPTER 1

  1. Einstein, “Autobiographical Notes” [1949], 31. On the universal “tick-tock” see Einstein, “The Principal Ideas of the Theory of Relativity” [after December 1916], Collected Papers, vol. 7, 1–7, on 5. On Newtonian time and space: Rynasiewicz, “Newton’s Scholium” (1995).

  2. We can now read Einstein’s work through the extraordinary scholarship of several generations of historians. This literature is so vast that I can refer only a few sources here—they serve as entry points into the wider literature: for both superb editorial comments and meticulous reproduction of documents, Stachel et al., eds., Collected Papers (1987–); for secondary literature, Holton, Thematic Origins of Scientific Thought (1973); Miller, “Einstein’s Special Theory of Relativity” (1981); Miller, Frontiers (1986); Darrigol, Electrodynamics (2000); Pais, Subtle is the Lord (1982); Warwick, “Role of the Fitzgerald-Lorentz Contraction Hypothesis” (1991); idem, “Cambridge Mathematics and Cavendish Physics” (part I, 1992; part II, 1993); Paty, Einstein philosophe (1993); M. Janssen, A Comparison between Lorentz’s Ether Theory and Special Relativity in the Light of the Experiments of Trouton and Noble, unpublished doctoral dissertation, University of Pittsburgh, 1995; and Fölsing, Albert Einstein (1997). For collections of essays by leading scholars, see “Einstein in Context,” Science in Context 6 (1993), and Galison, Gordin, and Kaiser, Science and Society (2001). For an extensive bibliography of other historical works on special relativity: Cassidy, “Understanding” (2001).

  3. The scholarship on Poincaré, also vast, is now coming into its own with the work of the Nancy-based project of the Archives Henri Poincaré, which is publishing the scientific correspondence. See, for example, Nabonnand, ed., Poincaré–Mittag-Leffler (1999); published articles are mostly in Oeuvres (1934–53). An overview of current work on Poincaré’s technical work may be found in the literature of note 2 above (especially works by Darrigol and Miller) along with references cited there, as well as the volume by Paty on the links between Poincaré’s physics and philosophy; see also the excellent volume, Greffe, Heinzmann, and Lorenz, eds., Henri Poincaré, Science and Philosophy (1996). Rollet’s excellent dissertation surveys Poincaré’s role as a popularizer and philosopher—it also contains a fine bibliography; see Henri Poincaré, “Des Mathématiques à la Philosophie. Études du parcours intellectuel, social et politique d’un mathématicien au début du siècle,” unpublished doctoral dissertation, University of Nancy 2, 1999.

  4. Galison, “Minkowski’s Space-Time” (1979).

  5. Einstein, “Elektrodynamik bewegter Körper” (1905), 893; I have used a (slightly modified) version of the translation given in Miller, Einstein’s Special Theory of Relativity (1981), 392–93.

  6. Ibid.

  7. See the sources in note 2 above; on the ether, Cantor and Hodge, eds., Conceptions of Ether (1981).

  8. For Heisenberg on his discussions with Einstein about the critique of absolute time, Physics and Beyond (1971), 63; other quantum theorists (Max Born and Pascual Jordan) also modeled their new physics on Einstein’s simultaneity convention, Cassidy, Uncertainty (1992), 198; Philipp Franck reported the “good joke” remark in Einstein (1953), 216.

  9. Schlick, “Meaning and Verification” (1987), 131; see also 47.

  10. Quine, “Lectures on Carnap,” 64.

  11. Einstein, Einstein on Peace (1960), 238–39, on 238.

  12. Einstein, Autobiographical Notes [1949], 33.

  13. Barthes, Mythologies (1972), 75–77.

  14. Poincaré, “Mathematical Creation” [1913], 387–88.

  15. Poincaré, Science and Hypothesis (1952), 78.

  16. Quoted in Seelig, ed., Helle Zeit-dunkle Zeit (1956), 71; trans. in Calaprice, The Quotable Einstein (1996), 182.

  17. Remotely set clocks were discussed by, among others, Charles Wheatstone and William Cook, the Scottish clockmaker, Alexander Bain, and the American inventor Samuel F. B. Morse. For Wheatstone, Cooke, and Morse, clock coordination came out of their work on telegraphy. See Welch, Time Measurement (1972), 71–72.

  18. For pre-1900 discussions of the extensive work on clock coordination, see, for example, the series of articles by Favarger, “L’Electricité et ses applications à la chronométrie” (Sept. 1884–June 1885), esp. 153–58, and “Les Horloges électriques” (1917); Ambronn, Handbuch der Astronomischen Instrumentenkunde (1899), esp. vol. 1, 183–87. On the expansion of the Bern network, see the Gesellschaft für elektrische Uhren in Bern, Jahresberichte, 1890–1910, Stadtarchiv Bern.

  19. Bernstein, Naturwissenschaftliche Volksbücher (1897), 62–64, 100–104. I would like to thank Jürgen Renn for helpful discussions about Bernstein.

  20. Poincaré, “Measure of Time” [1913], 233–34.

  21. Ibid., 235.

  22. Poincaré, “La Mesure du temps” (1970), 54. Slightly modified.

  CHAPTER 2

  1. Poincaré, “Les Polytechniciens” (1910), 266–67.

  2. Ibid., 268, 272–73.

  3. Ibid., 274–75, 278–79.

  4. Cahan, An Institute for an Empire (1989), esp. ch. 1.

  5. Monge’s polestar, descriptive geometry, plummeted in curricular importance from 153 hours (in 1800) to 92 hours (in 1842). Meanwhile, analysis, the rigorous study of mathematical functions, climbed to the top from its secondary role. Belhoste, Dahan, Dalmedico, and Picon, La formation polytechnicienne (1994), 20–21; Shinn, Savoir scientifique et pouvoir social (1980). On Monge’s projective geometry, see Daston, “Physicalist Tradition” (1986). On pedagogy in physics more generally, see the Warwick articles cited above and Olesko, Physics as a Calling (1991), and David Kaiser, Making Theory: Producing Physics and Physicists in Postwar America, unpublished doctoral dissertation, Harvard University, 2000.

  6. Poincaré on Cornu, “Cornu” (1910), esp. 106, 120–21, originally published in April 1902 (cf. Laurent Rollet, Henri Poincaré. Des Mathématiques à la Philosophie. Étude du parcours intellectuel, social et politique d’un mathématicien au début du siècle, unpublished doctoral dissertation, University of Nancy 2, 1999, 409); Cornu, “La Synchronisation électromagnétique” (1894).

  7. Picon opposes this distant respect for experiment to Terry Shinn’s characterization of the curriculum as more frankly hostile to experiment. Belhoste, Dahan, Dalmedico, and Picon, La formation polytechnicienne (1994), 170–71; Shinn, “Progress and Paradoxes” (1989).

  8. See Poincaré to his mother, e.g., C76/A74, C97/A131, C112/A150, C114/A152, C116/A162, in Correspondance de Henri Poincaré (unpubl. Archives—Centre d’Études et de Recherche Henri Poincaré, 2001), all from the academic year 1873–74.

  9. C79/A92, in Correspondance de Henri Poincaré (unpubl. Archives—Centre d’Études et de Recherche Henri Poincaré, 2001).

  10. Roy and Dugas, “Henri Poincaré” (1954), 8.

  11. See Nye, “Boutroux Circle” (1
979). Quotation from Archives—Centre d’Études et de Recherche Henri Poincaré microfilm 3, n.d. (probably 1877) in Laurent Rollet, Henri Poincaré. Des Mathématiques à la Philosophie. Étude du parcours intellectuel, social et politique d’un mathématicien au début du siècle, unpublished doctoral dissertation, University of Nancy 2, 1999, 78–79, on 79; also cf. 104. For the limits of science debate, see Keith Anderton, The Limits of Science: A Social, Political and Moral Agenda for Epistemology, unpublished doctoral dissertation, Harvard University, 1993.

  12. Calinon, “Étude Critique” (1885), 87.

  13. Ibid., 88–89; letter Calinon to Poincaré, 15 August 1886, in Correspondance de Henri Poincaré (unpubl. Archives—Centre d’Études et de Recherche Henri Poincaré, 2001).

  14. Calinon to Poincaré, 15 August 1886, in Correspondance de Henri Poincaré (unpubl. Archives—Centre d’Études et de Recherche Henri Poincaré, 2001).

  15. Roy and Dugas, “Henri Poincaré” (1954), 20.

  16. Ibid., 18.

  17. Ibid., 17–18.

  18. Ibid., 23; on Caen appointment see Gray and Walter, Henri Poincaré (1997), 1.

  19. On Poincaré’s emphasis on curves see Gray, “Poincaré” (1992); Gilain, “La théorie qualitative de Poincaré” (1991); Goroff, Introduction, in Poincaré, New Methods (1993), I9. Two fine articles on Poincaré and chaos are Gray, “Poincaré in the Archives” (1997), and (more technical) Andersson, “Poincaré’s Discovery of Homoclinic Points” (1994).