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The philosophy of physics
Studies in History and Philosophy of Modern Physics 33 (2002) 725–747
Book reviews The philosophy of physics Roberto Torretti; Cambridge University Press, Cambridge, 1999, pp. xvi+512, index, US $70.00, ISBN 0-521-56259-7 (hbk), 0-521-56571-5 (pbk) The Evolution of Modern Philosophy series, to which The Philosophy of Physics belongs, aims to illuminate the subject by examining it in its historical context. In the preface, Torretti writes that, A vein of philosophical thinking about the phenomena of nature runs through the four-century-old tradition of physics and holds it together. This philosophy in physics carries more weight in the book than the reflections about physics conducted by philosophers. Our study of the evolution of the modern philosophy of physics will therefore pay much attention to the conceptual development of physics itself (p. xiii). Torretti follows through on this plan with an astonishingly rich and detailed summary of the principal theories in physics from Galileo to the present day, explaining their historical, conceptual, interpretive, speculative, and empirical sources. At the end, he ties this picture together with his own account of the kind of description of the world with which physics provides us, and the ways in which the practice of physics contributes to the ongoing evolution of such descriptions. Torretti begins with a sketch of Aristotelian ideas and the reactions to these in the early modern period by people such as Huygens and Leibniz, but especially by Descartes and Galileo. This sets the stage for an account of Newton’s mechanics: the nature of the theory, and both Newton’s attitude towards the theory and his precepts for theory development, at least as Newton himself described these. There follows discussion of the worries about action-at-a-distance, and then a detailed technical presentation of analytic mechanics as it unfolded in the 18th and 19th centuries. Chapter 3 pauses in the exposition of physics to briefly discuss Leibniz and Berkeley, and then presents in great detail many aspects of Kant’s philosophy. Returning to mathematics and physics, Chapter 4, ‘‘The Rich Nineteenth Century’’, traces the development, first of non-Euclidean geometries, and then of field theories: from Euler’s fluid dynamics, through field characterizations of gravitation by Laplace and Poisson, to the flowering of electromagnetic field theory from Faraday’s ‘lines of force’, through Maxwell’s general electromagnetic theory. Next, Torretti sketches the development of conservation of energy, thermodynamics, and, finally, statistical mechanics, with its puzzling features and sometimes problematic appeal to
726
Book reviews / Studies in History and Philosophy of Modern Physics 33 (2002) 725–747
various notions of probability. Mathematics, made important by Galileo and central by Newton, continues to expand both in its scope and power, providing the vehicle for the new concepts that arise in all these developments. Chapter 4 ends with a brief sketch of relevant interpretive views of Whewell, Peirce, Mach, and Duhem, picked from among many as the ones1 that Torretti feels had, directly or indirectly, the greatest impact on the philosophy of the late 20th century. Chapters 5 and 6, respectively, treat relativity theory and quantum mechanics. For each, Torretti sketches the conceptual history, the fundamental ideas of the theory, and their main interpretive puzzles. Torretti judges both theories to provide ‘‘yexemplary cases of far-reaching conceptual change in fundamental physics, firmly rooted in the tradition they go beyond. As such they illustrate with exceptional clarity the way in which rupture and continuity are combined in the history of physics’’ (p. 250). Torretti also maintains that, in the case of relativity, the difficulty in assimilating the theory’s new concepts has been the source of ‘‘the so-called philosophical problems of relativity’’ (p. 250) which, when properly understood, are simply misunderstandings of (or resistance to) relativity’s conceptual innovations. For quantum theories, he sketches the issues, as he sees them, surrounding the EPR paradox, the problem of measurement, complementary, hidden variables, quantum logic, and ‘many worlds’ interpretations. In many cases he here also takes problems to arise as the result of failure to understand, or resistance to, the theory’s dramatic conceptual innovations. But on the whole, he sees more substance in the interpretive problems of quantum theories than in those of relativity theory, or, at the very least, failure so far to lay certain problems to rest by a proper perspective on the theory’s conceptual structure. Where does this conceptual history leave us? A few words cannot do justice to Torretti’s evaluation in Chapter 7, but I will attempt a sketch. In Torretti’s evaluation, ‘‘The most distinctive feature of modern physics is its use of mathematics and experiment, indeed its joint use of them’’ (p. 2). This involved a fundamental break with the Aristotelian tradition which held that true natures are destroyed when simplifications or experimental artifice take them out of their full living context: ‘‘While Aristotelian science favored loving attention to detail, through which alone one could succeed in conceiving the real in its full concreteness, Galileo and his followers conducted their research with scissors and blinkers [to eliminate distraction from inessential—or less important—details]. The natural processes and states of affairs under study were represented by simplified models, manageable instances of definite mathematical structures’’ (pp. 431–432). Writers in the early modern period generally held that God was the author of the ‘‘book of nature’’ which Galileo took to be written in the ‘‘language of mathematics’’. While, today, few would so think of the authorship, ‘‘yone implication of seventeenth-century theological commitments has lingered on as a source of confusion. Like the smile of the Cheshire cat, the idea of a ready-made world continues to haunt a philosophical tradition from which the idea of its Maker [assumed to use ‘‘ythe thriftiest means to achieve the richest variety and abundance of effects’’ (p. 406)] has long vanished. Although everyone is aware that physicists 1
Along with Poincar!e and Helmholtz—for whom Torretti refers the readers to his treatments elsewhere.
Book reviews / Studies in History and Philosophy of Modern Physics 33 (2002) 725–747
727
work on selected aspects of reality using idealized models that cannot claim perfect adequacy, the dream persists of a final theory of everything representing the true mathematical structure of the universe’’ (pp. 432–433). At this juncture, Torretti appeals to three strands in Kant’s thinking (pp. 433–435). First, Kant de-theologized physics by taking physics to concern only objects of human experience and not any approximation to a God’s eye view of things-in-themselves. Second, according to one of the conflicting strands in Kant’s work, phenomena are never fully determinate. Instead, in the shaping of experience, the human understanding progressively makes phenomena more and more determinate, without ever reaching the sort of full exactitude that might be exemplified by things-in-themselves. Third, Kant does not view mathematics as the geometry established by God and to be discerned by us. Instead, mathematics is something that perceivers of phenomena contribute in the very construction of the phenomena observed. Kant took these contributions to be fixed. But, having given up that facet of his philosophy, we can see reason, as characterized by the foregoing three features, to be ‘open ended’, which Torretti in turn takes to support Einstein’s view that ‘‘ythe ‘concepts and fundamental laws’ of physics are ‘free inventions of the human mind’y’’ (p. 436, quoting Einstein), as most dramatically illustrated by the advent of relativity and quantum theories. This Kantian perspective complements the historical perspective that ‘‘ymodern mathematical physics was born of the realization that earlier [Aristotelian] attempts to grasp the entire fabric of the world in one fell swoop had failed altogether’’. Instead, Since the seventeenth century, physicists have been focusing on particular patterns that they isolate and grasp by means of suitably contrived mathematical concepts. y In this they were well served by their decision to geometrize physics, to conceive the patterns in nature as instances of mathematical structures. However, to do it they had to replace in their minds the concrete physical processes that they intend to study—which were unmanageably complex and entangled with the rest of the word—with simplified models that truly instantiated such abstract mathematical structures as they could handle. y But [this approach] also entails that the ‘empirical claim’ of a physical theoryy viz., that the theory’s applications are actual examples of its characteristic mathematical structure, must be taken with a sizable pinch of salt, for the structure is instantiated by the models, not by the physical realities that the models represent only to within some specified or unspecified but anyway finite degree of approximation. y From this standpoint a theory is—or is not—exactly true of its purported models, which, in turn, are good or bad representatives of the physical phenomena for which they are supposed to stand. And, of course, a particular model of a particular process may be good enough for one purpose and not for another2 (pp. 415–417). 2
This way of thinking of the nature and function of theories is strikingly close to that described by Giere (1988, Chapter 3), and there are also many points of agreement with Cartwright’s earlier (1983), neither of which Torretti mentions. In a personal communication Professor Torretti has told me that he also sees a great deal of similarity on the issues in question with the views of Cartwright and Giere, both of whom he holds in very high esteem as philosophers of science, and that he deeply regrets the oversight of not having mentioned this in the book.
728
Book reviews / Studies in History and Philosophy of Modern Physics 33 (2002) 725–747
I am in wholehearted agreement with both this evaluation and the suggested Kantian underpinnings, and I rejoice in the rich historical survey that appears to me to support them abundantly. I can also add a few caveats for the reader. Torretti hopes (p. xiv) that much of the book will be accessible to readers with a solid high school and perhaps some college training in physics and mathematics, and no professional training in philosophy. I suspect that this is overly optimistic. Torretti often pours on the detail of physics, mathematics, and philosophy, as if from an irrepressible enjoyment they inspire in him, but sometimes beyond what is needed to tell his story. Most readers of this journal will not have difficulty with the formal material, but some may have difficulty with some of the philosophy, especially in the treatment of Kant. But those who will read around the material that goes over their heads will still get the main lines of Torretti’s story. When it comes to evaluating interpretive positions, Torretti often dismisses them with a one liner, for example, when he says that ‘‘ythe doctrine of senseless [better known as the causal theory of] reference, although perhaps admissible in the case of the proper names of individuals, is inapplicable to general terms, because the recognition of different individuals as instances of the same class depends on the concept by which one grasps them’’ (p. 422). Such short shrift may please those who agree on the point in question, and often such readers will immediately see how the suggested argument is to be carried out in detail. (For the example I have cited, Torretti himself elaborated in his (1990, pp. 51–70).) Readers who disagree may be less pleased, and those not familiar with the issues may occasionally be misled as to how involved and delicate they can be. Finally, some historical claims are contentious and some bypass known historical complexity without acknowledgment, albeit in aid of making a sound conceptual point. For example, in evaluating Newton’s attitude towards action-at-a-distance, I read Torretti as suggesting that Newton himself did not believe that ‘‘something was wanting in his theory’’: rather, ‘‘[Newton’s] remark [in the general scholium of the second edition of the Principia] that the force of gravity does not operate like the usual mechanical causes seems designed to warn us that the phenomena effectively preclude the kind of explanation that his adversaries foolishly demanded’’ (p. 79). While this may be a fair enough characterization of how many of Newton’s successors read Newton (which is what is really relevant to the story that Torretti is telling), some historians strenuously disagree with this as an evaluation of Newton’s own attitude or of what he meant to convey in the passage cited.3 As a second example, when explaining Einstein’s development of special relativity, Torretti’s exposition may suggest (although he does not explicitly say) that Einstein was responding to Michelson and Morley’s failure to detect the aether-wind (pp. 250–252). While I see nothing to fault in the presentation of the conceptual structure 3 Westfall’s treatment is at least consistent with Torretti’s evaluation—see Westfall (1980, pp. 509, 530– 531, 749, 779, and 794). But Dobbs (1991) vigorously dissents. See pp. 149–150, 188, 191, 210, 229, 247, 252–253, and Chapters 6 and 7 passim.
Book reviews / Studies in History and Philosophy of Modern Physics 33 (2002) 725–747
729
of the theory as we understand it today, current scholarship insists that Einstein was much more moved by two other considerations: the statement of electromagnetic theory that appeared to give a different account of the effects of a magnet moving relative to a ‘stationary’ conductor as opposed to a conductor moving relative to a ‘stationary’ magnet; and, the thought experiment of running after a light beam at the speed of light, which on the classical conception, should make the light appear as a static spatial waveform, something that Maxwell’s equations could not accommodate.4 As one final example, Torretti explicitly claims that ‘‘Suppes took his cue from Bourbaki’’ (pp. 412–413) in introducing what is generally known as the ‘semantic’, but which Torretti persuasively argues should rather be called the ‘structuralist’, view of theories. While recasting the semantic view in terms of the structuralist tradition in mathematics is conceptually illuminating, it seems to me inaccurate to read such recasting into the history of the subject.5 And Torretti’s claim (p. 414) that the structure in question for a theory is specified by axioms is explicitly rejected by principal advocates of the view,6 as it must be on pain of eliminating any substantive distinction between the semantic and received ‘syntactic’ view of theories. I mention such oversimplifications because some historical purists might be put off. I sincerely hope not; for this book is extraordinarily rich in excellent history, from the ancient Greeks to the present. Where there is some streamlining, I doubt that it in any serious way compromises Torretti’s picture and interpretation of the conceptual structure of mathematical physics as it has been passed down to us. Those willing to put in the work needed to study this book will be rewarded with what I believe is a most worthwhile perspective on the legacy we have inherited from Galileo onward.
References Cartwright, N. (1983). How the laws of physics lie. Oxford: Clarendon Press. Dobbs, B. J. T. (1991). The Janus faces of genius: The role of alchemy in Newton’s thought. Cambridge: Cambridge University Press. Giere, R. (1988). Explaining science: A cognitive approach. Chicago: Chicago University Press. Rynasiewicz, R. (2000). The construction of the special theory: Some queries and considerations. In D. Howard, & J. Stachel (Eds.), Einstein: The formative years, 1879–1909. Boston: Birkaeuser. Stachel, J. (1982). Einstein and Michelson: The context of discovery and the context of justification. Astronomische Nachrichten, 47–63. Suppe, F. (1989). The semantic conception of theories and scientific realism. Urbana: The University of Illinois Press. Suppes, P. (1967). What is a scientific theory? In S. Morgenbesser (Ed.), Philosophy of science today. New York: Basic Books. 4
See Stachel (1982), Rynasiewicz (2000), and Torretti’s own (1983a, b, pp. 48–50). Suppes may well have been working in a structuralist mathematical ‘climate’, and the references from Suppes that Torretti cites do have a ‘structuralist tone’, but I find no explicit reference to Bourbaki or structuralism. Van Fraassen explicitly cites the influence of Beth. Suppe (1989, pp. 5–20) gives a history of the subject. 6 See, e.g., van Fraassen (1987, p. 109), and Suppes (1967, pp. 58, 60–61). 5
730
Book reviews / Studies in History and Philosophy of Modern Physics 33 (2002) 725–747
Torretti, R. (1983a). Relativity and geometry. Oxford: Pergamon Press. Torretti, R. (1983b). Creative understanding: Philosophical reflections on physics. Chicago: Chicago University Press. Van Fraassen, B. (1987). The semantic approach to scientific theories. In N. Nersessian (Ed.), The process of science: Contemporary philosophical approaches to understanding scientific practice. Dordrecht: Martinus Nijhoff. Westfall, R. S. (1980). Never at rest: A biography of Isaac Newton. Cambridge: Cambridge University Press.
Paul Teller Department of Philosophy University of California at Davis, Davis, CA 95616, USA E-mail address: [email protected] PII: S 1 3 5 5 - 2 1 9 8 ( 0 2 ) 0 0 0 3 5 - 7
Concepts of mass in contemporary physics and philosophy Max Jammer; Princeton University Press, Princeton, 2000, xi+180pp., price US $41.50, ISBN 0-691-01017-X Before his two masterpieces on the intellectual history of quantum mechanics (Jammer, 1966, 1974), Max Jammer wrote three comparatively short but richly rewarding books, on the concepts of space, force, and mass (Jammer, 1954, 1957, 1961), which have often been reprinted and are treasured as exemplars of the historical approach to scientific ideas. The present book may be regarded as a continuation of this series. Like its predecessors, it gathers in a thin volume a wealth of wisely selected, clearly explained, and exactly documented information on its subject matter. Like them, it should stand ready-at-hand on the bookshelves of everyone concerned with natural philosophy and its history. Current concepts of mass are rooted in Newton’s notion of quantitas materiae, a conserved quantity characteristic of each body, which (1) enters in the measure of momentum as the scalar factor of velocity, and also measures a body’s performance as (2a) a source and (2b) a recipient of gravitational attraction. In 20th-century literature these three roles of Newton’s quantity of matter are often distributed among three conceptually distinct physical quantities, labelled (1) inertial mass, (2a) active gravitational mass, and (2b) passive gravitational mass, whose mutual proportionality or equality is a focus of theoretical agonizing and experimental research. Jammer denotes these three quantities by mi ; ma ; and mp ; respectively. Henri Poincare! (1908) distinguished between inertial and gravitational mass after he realized—at the same time as Einstein, but independently from him—that a body’s inertia, i.e., its resistance to velocity change, increases with its actual velocity (relative to the chosen inertial frame of reference). This realization, together with the related discovery of mass–energy equivalence, inspired a similar distinction by Max Planck. ‘‘Thermal radiation in a thoroughly empty space enclosed by reflecting walls surely has inertial mass’’, he wrote, ‘‘but does it also have ponderable mass?’’ (Planck, 1907,
Book reviews The philosophy of physics Roberto Torretti; Cambridge University Press, Cambridge, 1999, pp. xvi+512, index, US $70.00, ISBN 0-521-56259-7 (hbk), 0-521-56571-5 (pbk) The Evolution of Modern Philosophy series, to which The Philosophy of Physics belongs, aims to illuminate the subject by examining it in its historical context. In the preface, Torretti writes that, A vein of philosophical thinking about the phenomena of nature runs through the four-century-old tradition of physics and holds it together. This philosophy in physics carries more weight in the book than the reflections about physics conducted by philosophers. Our study of the evolution of the modern philosophy of physics will therefore pay much attention to the conceptual development of physics itself (p. xiii). Torretti follows through on this plan with an astonishingly rich and detailed summary of the principal theories in physics from Galileo to the present day, explaining their historical, conceptual, interpretive, speculative, and empirical sources. At the end, he ties this picture together with his own account of the kind of description of the world with which physics provides us, and the ways in which the practice of physics contributes to the ongoing evolution of such descriptions. Torretti begins with a sketch of Aristotelian ideas and the reactions to these in the early modern period by people such as Huygens and Leibniz, but especially by Descartes and Galileo. This sets the stage for an account of Newton’s mechanics: the nature of the theory, and both Newton’s attitude towards the theory and his precepts for theory development, at least as Newton himself described these. There follows discussion of the worries about action-at-a-distance, and then a detailed technical presentation of analytic mechanics as it unfolded in the 18th and 19th centuries. Chapter 3 pauses in the exposition of physics to briefly discuss Leibniz and Berkeley, and then presents in great detail many aspects of Kant’s philosophy. Returning to mathematics and physics, Chapter 4, ‘‘The Rich Nineteenth Century’’, traces the development, first of non-Euclidean geometries, and then of field theories: from Euler’s fluid dynamics, through field characterizations of gravitation by Laplace and Poisson, to the flowering of electromagnetic field theory from Faraday’s ‘lines of force’, through Maxwell’s general electromagnetic theory. Next, Torretti sketches the development of conservation of energy, thermodynamics, and, finally, statistical mechanics, with its puzzling features and sometimes problematic appeal to
726
Book reviews / Studies in History and Philosophy of Modern Physics 33 (2002) 725–747
various notions of probability. Mathematics, made important by Galileo and central by Newton, continues to expand both in its scope and power, providing the vehicle for the new concepts that arise in all these developments. Chapter 4 ends with a brief sketch of relevant interpretive views of Whewell, Peirce, Mach, and Duhem, picked from among many as the ones1 that Torretti feels had, directly or indirectly, the greatest impact on the philosophy of the late 20th century. Chapters 5 and 6, respectively, treat relativity theory and quantum mechanics. For each, Torretti sketches the conceptual history, the fundamental ideas of the theory, and their main interpretive puzzles. Torretti judges both theories to provide ‘‘yexemplary cases of far-reaching conceptual change in fundamental physics, firmly rooted in the tradition they go beyond. As such they illustrate with exceptional clarity the way in which rupture and continuity are combined in the history of physics’’ (p. 250). Torretti also maintains that, in the case of relativity, the difficulty in assimilating the theory’s new concepts has been the source of ‘‘the so-called philosophical problems of relativity’’ (p. 250) which, when properly understood, are simply misunderstandings of (or resistance to) relativity’s conceptual innovations. For quantum theories, he sketches the issues, as he sees them, surrounding the EPR paradox, the problem of measurement, complementary, hidden variables, quantum logic, and ‘many worlds’ interpretations. In many cases he here also takes problems to arise as the result of failure to understand, or resistance to, the theory’s dramatic conceptual innovations. But on the whole, he sees more substance in the interpretive problems of quantum theories than in those of relativity theory, or, at the very least, failure so far to lay certain problems to rest by a proper perspective on the theory’s conceptual structure. Where does this conceptual history leave us? A few words cannot do justice to Torretti’s evaluation in Chapter 7, but I will attempt a sketch. In Torretti’s evaluation, ‘‘The most distinctive feature of modern physics is its use of mathematics and experiment, indeed its joint use of them’’ (p. 2). This involved a fundamental break with the Aristotelian tradition which held that true natures are destroyed when simplifications or experimental artifice take them out of their full living context: ‘‘While Aristotelian science favored loving attention to detail, through which alone one could succeed in conceiving the real in its full concreteness, Galileo and his followers conducted their research with scissors and blinkers [to eliminate distraction from inessential—or less important—details]. The natural processes and states of affairs under study were represented by simplified models, manageable instances of definite mathematical structures’’ (pp. 431–432). Writers in the early modern period generally held that God was the author of the ‘‘book of nature’’ which Galileo took to be written in the ‘‘language of mathematics’’. While, today, few would so think of the authorship, ‘‘yone implication of seventeenth-century theological commitments has lingered on as a source of confusion. Like the smile of the Cheshire cat, the idea of a ready-made world continues to haunt a philosophical tradition from which the idea of its Maker [assumed to use ‘‘ythe thriftiest means to achieve the richest variety and abundance of effects’’ (p. 406)] has long vanished. Although everyone is aware that physicists 1
Along with Poincar!e and Helmholtz—for whom Torretti refers the readers to his treatments elsewhere.
Book reviews / Studies in History and Philosophy of Modern Physics 33 (2002) 725–747
727
work on selected aspects of reality using idealized models that cannot claim perfect adequacy, the dream persists of a final theory of everything representing the true mathematical structure of the universe’’ (pp. 432–433). At this juncture, Torretti appeals to three strands in Kant’s thinking (pp. 433–435). First, Kant de-theologized physics by taking physics to concern only objects of human experience and not any approximation to a God’s eye view of things-in-themselves. Second, according to one of the conflicting strands in Kant’s work, phenomena are never fully determinate. Instead, in the shaping of experience, the human understanding progressively makes phenomena more and more determinate, without ever reaching the sort of full exactitude that might be exemplified by things-in-themselves. Third, Kant does not view mathematics as the geometry established by God and to be discerned by us. Instead, mathematics is something that perceivers of phenomena contribute in the very construction of the phenomena observed. Kant took these contributions to be fixed. But, having given up that facet of his philosophy, we can see reason, as characterized by the foregoing three features, to be ‘open ended’, which Torretti in turn takes to support Einstein’s view that ‘‘ythe ‘concepts and fundamental laws’ of physics are ‘free inventions of the human mind’y’’ (p. 436, quoting Einstein), as most dramatically illustrated by the advent of relativity and quantum theories. This Kantian perspective complements the historical perspective that ‘‘ymodern mathematical physics was born of the realization that earlier [Aristotelian] attempts to grasp the entire fabric of the world in one fell swoop had failed altogether’’. Instead, Since the seventeenth century, physicists have been focusing on particular patterns that they isolate and grasp by means of suitably contrived mathematical concepts. y In this they were well served by their decision to geometrize physics, to conceive the patterns in nature as instances of mathematical structures. However, to do it they had to replace in their minds the concrete physical processes that they intend to study—which were unmanageably complex and entangled with the rest of the word—with simplified models that truly instantiated such abstract mathematical structures as they could handle. y But [this approach] also entails that the ‘empirical claim’ of a physical theoryy viz., that the theory’s applications are actual examples of its characteristic mathematical structure, must be taken with a sizable pinch of salt, for the structure is instantiated by the models, not by the physical realities that the models represent only to within some specified or unspecified but anyway finite degree of approximation. y From this standpoint a theory is—or is not—exactly true of its purported models, which, in turn, are good or bad representatives of the physical phenomena for which they are supposed to stand. And, of course, a particular model of a particular process may be good enough for one purpose and not for another2 (pp. 415–417). 2
This way of thinking of the nature and function of theories is strikingly close to that described by Giere (1988, Chapter 3), and there are also many points of agreement with Cartwright’s earlier (1983), neither of which Torretti mentions. In a personal communication Professor Torretti has told me that he also sees a great deal of similarity on the issues in question with the views of Cartwright and Giere, both of whom he holds in very high esteem as philosophers of science, and that he deeply regrets the oversight of not having mentioned this in the book.
728
Book reviews / Studies in History and Philosophy of Modern Physics 33 (2002) 725–747
I am in wholehearted agreement with both this evaluation and the suggested Kantian underpinnings, and I rejoice in the rich historical survey that appears to me to support them abundantly. I can also add a few caveats for the reader. Torretti hopes (p. xiv) that much of the book will be accessible to readers with a solid high school and perhaps some college training in physics and mathematics, and no professional training in philosophy. I suspect that this is overly optimistic. Torretti often pours on the detail of physics, mathematics, and philosophy, as if from an irrepressible enjoyment they inspire in him, but sometimes beyond what is needed to tell his story. Most readers of this journal will not have difficulty with the formal material, but some may have difficulty with some of the philosophy, especially in the treatment of Kant. But those who will read around the material that goes over their heads will still get the main lines of Torretti’s story. When it comes to evaluating interpretive positions, Torretti often dismisses them with a one liner, for example, when he says that ‘‘ythe doctrine of senseless [better known as the causal theory of] reference, although perhaps admissible in the case of the proper names of individuals, is inapplicable to general terms, because the recognition of different individuals as instances of the same class depends on the concept by which one grasps them’’ (p. 422). Such short shrift may please those who agree on the point in question, and often such readers will immediately see how the suggested argument is to be carried out in detail. (For the example I have cited, Torretti himself elaborated in his (1990, pp. 51–70).) Readers who disagree may be less pleased, and those not familiar with the issues may occasionally be misled as to how involved and delicate they can be. Finally, some historical claims are contentious and some bypass known historical complexity without acknowledgment, albeit in aid of making a sound conceptual point. For example, in evaluating Newton’s attitude towards action-at-a-distance, I read Torretti as suggesting that Newton himself did not believe that ‘‘something was wanting in his theory’’: rather, ‘‘[Newton’s] remark [in the general scholium of the second edition of the Principia] that the force of gravity does not operate like the usual mechanical causes seems designed to warn us that the phenomena effectively preclude the kind of explanation that his adversaries foolishly demanded’’ (p. 79). While this may be a fair enough characterization of how many of Newton’s successors read Newton (which is what is really relevant to the story that Torretti is telling), some historians strenuously disagree with this as an evaluation of Newton’s own attitude or of what he meant to convey in the passage cited.3 As a second example, when explaining Einstein’s development of special relativity, Torretti’s exposition may suggest (although he does not explicitly say) that Einstein was responding to Michelson and Morley’s failure to detect the aether-wind (pp. 250–252). While I see nothing to fault in the presentation of the conceptual structure 3 Westfall’s treatment is at least consistent with Torretti’s evaluation—see Westfall (1980, pp. 509, 530– 531, 749, 779, and 794). But Dobbs (1991) vigorously dissents. See pp. 149–150, 188, 191, 210, 229, 247, 252–253, and Chapters 6 and 7 passim.
Book reviews / Studies in History and Philosophy of Modern Physics 33 (2002) 725–747
729
of the theory as we understand it today, current scholarship insists that Einstein was much more moved by two other considerations: the statement of electromagnetic theory that appeared to give a different account of the effects of a magnet moving relative to a ‘stationary’ conductor as opposed to a conductor moving relative to a ‘stationary’ magnet; and, the thought experiment of running after a light beam at the speed of light, which on the classical conception, should make the light appear as a static spatial waveform, something that Maxwell’s equations could not accommodate.4 As one final example, Torretti explicitly claims that ‘‘Suppes took his cue from Bourbaki’’ (pp. 412–413) in introducing what is generally known as the ‘semantic’, but which Torretti persuasively argues should rather be called the ‘structuralist’, view of theories. While recasting the semantic view in terms of the structuralist tradition in mathematics is conceptually illuminating, it seems to me inaccurate to read such recasting into the history of the subject.5 And Torretti’s claim (p. 414) that the structure in question for a theory is specified by axioms is explicitly rejected by principal advocates of the view,6 as it must be on pain of eliminating any substantive distinction between the semantic and received ‘syntactic’ view of theories. I mention such oversimplifications because some historical purists might be put off. I sincerely hope not; for this book is extraordinarily rich in excellent history, from the ancient Greeks to the present. Where there is some streamlining, I doubt that it in any serious way compromises Torretti’s picture and interpretation of the conceptual structure of mathematical physics as it has been passed down to us. Those willing to put in the work needed to study this book will be rewarded with what I believe is a most worthwhile perspective on the legacy we have inherited from Galileo onward.
References Cartwright, N. (1983). How the laws of physics lie. Oxford: Clarendon Press. Dobbs, B. J. T. (1991). The Janus faces of genius: The role of alchemy in Newton’s thought. Cambridge: Cambridge University Press. Giere, R. (1988). Explaining science: A cognitive approach. Chicago: Chicago University Press. Rynasiewicz, R. (2000). The construction of the special theory: Some queries and considerations. In D. Howard, & J. Stachel (Eds.), Einstein: The formative years, 1879–1909. Boston: Birkaeuser. Stachel, J. (1982). Einstein and Michelson: The context of discovery and the context of justification. Astronomische Nachrichten, 47–63. Suppe, F. (1989). The semantic conception of theories and scientific realism. Urbana: The University of Illinois Press. Suppes, P. (1967). What is a scientific theory? In S. Morgenbesser (Ed.), Philosophy of science today. New York: Basic Books. 4
See Stachel (1982), Rynasiewicz (2000), and Torretti’s own (1983a, b, pp. 48–50). Suppes may well have been working in a structuralist mathematical ‘climate’, and the references from Suppes that Torretti cites do have a ‘structuralist tone’, but I find no explicit reference to Bourbaki or structuralism. Van Fraassen explicitly cites the influence of Beth. Suppe (1989, pp. 5–20) gives a history of the subject. 6 See, e.g., van Fraassen (1987, p. 109), and Suppes (1967, pp. 58, 60–61). 5
730
Book reviews / Studies in History and Philosophy of Modern Physics 33 (2002) 725–747
Torretti, R. (1983a). Relativity and geometry. Oxford: Pergamon Press. Torretti, R. (1983b). Creative understanding: Philosophical reflections on physics. Chicago: Chicago University Press. Van Fraassen, B. (1987). The semantic approach to scientific theories. In N. Nersessian (Ed.), The process of science: Contemporary philosophical approaches to understanding scientific practice. Dordrecht: Martinus Nijhoff. Westfall, R. S. (1980). Never at rest: A biography of Isaac Newton. Cambridge: Cambridge University Press.
Paul Teller Department of Philosophy University of California at Davis, Davis, CA 95616, USA E-mail address: [email protected] PII: S 1 3 5 5 - 2 1 9 8 ( 0 2 ) 0 0 0 3 5 - 7
Concepts of mass in contemporary physics and philosophy Max Jammer; Princeton University Press, Princeton, 2000, xi+180pp., price US $41.50, ISBN 0-691-01017-X Before his two masterpieces on the intellectual history of quantum mechanics (Jammer, 1966, 1974), Max Jammer wrote three comparatively short but richly rewarding books, on the concepts of space, force, and mass (Jammer, 1954, 1957, 1961), which have often been reprinted and are treasured as exemplars of the historical approach to scientific ideas. The present book may be regarded as a continuation of this series. Like its predecessors, it gathers in a thin volume a wealth of wisely selected, clearly explained, and exactly documented information on its subject matter. Like them, it should stand ready-at-hand on the bookshelves of everyone concerned with natural philosophy and its history. Current concepts of mass are rooted in Newton’s notion of quantitas materiae, a conserved quantity characteristic of each body, which (1) enters in the measure of momentum as the scalar factor of velocity, and also measures a body’s performance as (2a) a source and (2b) a recipient of gravitational attraction. In 20th-century literature these three roles of Newton’s quantity of matter are often distributed among three conceptually distinct physical quantities, labelled (1) inertial mass, (2a) active gravitational mass, and (2b) passive gravitational mass, whose mutual proportionality or equality is a focus of theoretical agonizing and experimental research. Jammer denotes these three quantities by mi ; ma ; and mp ; respectively. Henri Poincare! (1908) distinguished between inertial and gravitational mass after he realized—at the same time as Einstein, but independently from him—that a body’s inertia, i.e., its resistance to velocity change, increases with its actual velocity (relative to the chosen inertial frame of reference). This realization, together with the related discovery of mass–energy equivalence, inspired a similar distinction by Max Planck. ‘‘Thermal radiation in a thoroughly empty space enclosed by reflecting walls surely has inertial mass’’, he wrote, ‘‘but does it also have ponderable mass?’’ (Planck, 1907,