"Representing Electrons" by Theodore Arabatzis
An ambitious and pretty successful biography of the electron
Theodore Arabatzis, Representing Electrons: A Biographical Approach to Theoretical Entities. Chicago and London: The University of Chicago Press, 2006

In Representing Electrons, Theodore Arabatzis gives a detailed account of scientific inquiry into the electron, covering roughly the years 1891-1824. The main message is that scientific entities have a "life of their own": they can act independently of theory, theoreticians, and experimenters. In delivering this message, Arabatzis makes a bold and largely successful attempt to bring the historical and philosophical approaches into a mutually stimulating relationship.

You can see Arabatzis’ dual interest in the history and philosophy in his choice of advisors and collaborators. While at Princeton University Arabatzis came into contact with the philosopher Bas van Fraassen, and numerous other philosophers are energetically deployed in the body of the book: Karl Popper, Larry Laudan and Thomas Nickels are quoted on the topic of “problem situations”, Paul Feyerabend and Ian Hacking on scientific realism, and Hilary Putman on theories of reference. Also featured in the author's acknowledgments are prominent historians of science, including Jed Buchwald, Warwick Taylor and Ernan McMullin.

In Representing Electrons, Arabatzis puts his multi-layered background to good use. Three themes dominate the book: realism and meaning change; the "discovery" of scientific entities; and the autonomy of theoretical entities. In Arabatzis's account, each of these themes has a historical and a philosophical dimension.

Take the topic of scientific discovery. Here, Arabatzis corrects the commonly-held view that J.J. Thomson “discovered” the electron. In doing so he uses the historian’s tools, probing scientists’ ideas through their scientific papers (such J.J. Thomson’s Cathode Ray article in Philosophical Magazine) and other writings (Lorentz’s Nobel Prize speech, for example. In later chapters he uses interviews conducted by Thomas Kuhn.) But this historical spade-work is guided by a philosophical discussion of “discovery” that draws on Hacking, Kuhn and Nickles. Here Arabatzis argues for the possibility of an account of discovery that is realism-neutral, and stresses the gradual, consensual nature of discovery: what we call “discoveries” are usually something more like “constructions.”

A similar pattern emerges in the next four chapters. Here, Arabatzis goes into considerable detail when dealing with the key episodes in the evolution of ideas about the electron, following the concept as it moves between various stages within physics (from classical to quantum and relativistic physics) and between disciplines (physics and chemistry). But his account is held together by the broad idea that the electron had a "life of its own," a capacity to throw up problems and suggest solutions.

Throughout the account, Arabatzis keeps a close eye on the stability of the "electron" concept through time and between practitioners. This conceptual stability comes to the fore in the concluding discussion about meaning change and realism in science. Arabatzis goes over some responses to Paul Feyerabend, who argued from meaning change to the non-existence of unobservable entities. When these responses fail, what is left for the realist? Arabatzis gives a two-fold answer. First, the case for realism can be supported by reference to the "writings" of the putative entity: if multiple observations give evidence of the same unobservable entity, you can be pretty sure the entity is real. Secondly, the case for realism can be supported by a historical account of a concepts' stability over time.

The final paragraph of the book draws out the implications of these arguments for historical accounts of the electron. Hence the attempted union of history and philosophy is carried right to the end of the book. Is this attempt successful? On the whole, the answer must be “yes.” There is a danger here of artificially gluing different disciplines together, but Arabatzis largely avoids this danger. The philosophical discussion in the concluding chapter draws on examples from the author’s historical account; during the historical discussion the reader is constantly reminded of the philosophical questions at hand; and the philosophy comments not only on the science of microphysics but also on the methodology of historians of physics.

One might complain that the philosophical discussion about realism and meaning change is independent of the “biographical approach” that Arabatzis takes to the electron. At least, Arabatzis seems to be in two minds about this. On the one hand, he pursues the “historicist” approach to discovery precisely because it does not require any prior commitment to realism or anti-realism: it keeps everyone happy. On the other hand, he writes the concluding chapter (on meaning-variance and realism) largely to justify his historical methodology: “for those who disbelieve in the existence of unobservable entities...a historical approach devoted to its representation may seem vacuous.”

In Arabatzis' defense, the final chapter does explore the implications of the historical account for the realism debate (not just the other way round). And his equivocation here may be just another sign that historians and philosophers (not just Arabatzis) have inconsistent aims. To a historian, who is worried about what happened in the past, the key criterion for existence of an entity is whether the entity was significant for past scientists. To a philosopher, the key criterion is whether it is, in fact, right to think that the entity exists. If Arabatzis is in two minds here, the problem does not lie with him, for being inconsistent, but with the two disciplines, for being different; Arabatzis' only real fault is not to clearly acknowledge this difference.

In the well-tilled field of historical research into the electron, novelty is crucial to a book’s success. The chief novelty in Representing Electrons is is the idea that concepts have a "life of their own." This idea does give rise to a fresh retelling of the atomic story: a vivid picture emerges of the electron standing on the outside of theory, teasing physicists into dead-ends and leading them on to unexpected new insights.

But Arabatzis has only given us a new picture insofar as he has applied it to a new entity: the ideas behind the picture are unexciting. For example, Arabatzis writes about Sommerfeld's selection rules, and how his “struggle to discipline the electron in a principled way ran into difficulties with its writings.” But do these metaphors convey anything more than the mundane fact that Sommerfeld had trouble matching his theory about the electron to his observations about it? A similar question may be asked about the fact that physicists found heuristic value of theories, and that they had trouble making the concept of the electron internally coherent. If the answers to these questions are “no”, this is not to say that there is no value in Arabatzis' biographical approach. It just means that the value lies in its contribution to the narrative structure of the book, and not to its philosophical depth.

One can always make quibbles about exposition, especially when an author tries to describe technical paths of reasoning. Overall Arabatzis does a good job here: a basic knowledge of maths is required to understand the derivations, but most of the discussion is within the reach of the ordinary reader. However, the book would benefit from more images of the relevant theories (eg. of atomic structure) and experimental results (especially spectral patterns). This would not just aid reader understanding. Copies of original diagrams of the electron would give a better idea of how physicists "represented" the electron to eachother and to themselves.

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