The Age of Chance Reserved for the Winning Side of the Struggle

BOOKS & ARTS NATURE|Vol 446|22 March 2007 unfortunately, that Lindley’s perceptive and sympathetic treatment of ideas and figures is The age of chance reserved for the winning side of the struggle. He marginalizes Einstein’s concerns by pre- Uncertainty: Einstein, Heisenberg, Bohr, posal for a radically non-newtonian dynamic senting him as a young revolutionary turned and the Struggle for the Soul of Science theory in which particles followed trajectories old reactionary. Lindley keeps returning to by David Lindley determined by an associated wave. De Bro- Einstein’s desire for causality, while down- Doubleday: 2007. 272 pp. $26 glie showed how this could account for basic playing Einstein’s equally strong insistence that interference phenomena (as waves) as well as physics, causal or not, should deal with nature Arthur Fine quantized energy (as particles). That drew it to itself, not just our observations. The author In Uncertainty, David Lindley tells the intrigu- the attention of Einstein and Schrödinger, who also overlooks Einstein’s radical critique of the ing tale of how Albert Einstein, Werner found the ideas promising, and to Heisenberg, classical, physical concepts used in quantum Heisenberg and Niels Bohr (among others) Pauli and Bohr, who felt threatened by them. theory, as well as his programme for develop- struggled to create and understand the new But de Broglie lacked a general treatment of ing new concepts, and his eventual openness quantum physics. Lindley organizes his tale the waves that guided his particles, and that is to an algebraic, rather than a spatiotemporal, around the issue of indeterminism, which Max where wave mechanics comes in. setting for the physics (not exactly a reaction- Born raised in 1926 in the paper that intro- The fifth Solvay conference, held in Brussels ary agenda). duced probability as fundamental to interpret- in October 1927, was a major event involving For a different perspective, readers may ing the quantum world. Within a year, at the nearly all the figures mentioned in Lindley’s be interested in David Cassidy’s Uncertainty: end of his paper on the uncertainty principle, story. Lindley describes the struggle between The Life and Science of Werner Heisenberg Heisenberg declared determinism (or cau- updated versions of wave and matrix mechan- (W. H. Freeman, 1991), Mara Beller’s Quantum sality) dead, a pronouncement that brought ics, and Einstein’s informal challenges. The Dialogue (University of Chicago Press, 1999), probability, chance and uncertainty into the confrontation also included an updated de and two books by Abraham Pais, Subtle is the quantum domain in a fundamental way. Broglie theory, with continuous space-time Lord (Oxford University Press, 1982) and Niels Lindley tracks the rise of chance from trajectories. Moreover, full determinism was Bohr’s Times (Clarendon, 1991). A forthcom- its roots in statistical reasoning (brownian guaranteed by linking de Broglie’s new dynam- ing book by Guido Bacciagaluppi and Antony motion and entropy) through to Bohr’s ‘jump- ics with Schrödinger’s waves. Lindley’s book Valentini, Quantum Theory at the Crossroads ing planetary model’ of the atom and beyond. misses all this, misrepresenting de Broglie (Cambridge University Press, 2007; available He selects important episodes from this ‘old’ as fighting a rearguard action on behalf of online at http://arxiv.org/abs/quant-ph/ quantum theory and then retells them in a Schrödinger. It’s as if the head-on collision over 0609184), will offer a reanalysis of the 1927 lively and insightful manner. This provides the determinism, the introduction of a radically Solvay conference. background for Heisenberg’s theory of matrix different dynamics, the discussions, thought Uncertainty tells the tale of the struggle over mechanics and Erwin Schrödinger’s wave experiments, probing challenges and responses quantum theory from the perspective of an mechanics. The author tells how Bohr encour- never occurred. omniscient narrator. The narrator turns out not aged, derided, cajoled, inspired and browbeat Lindley touches on several significant later to be all that impartial. He is also not omnis- all sides to orchestrate the Copenhagen syn- events in his story, including an encounter cient, stumbling a few times (and not just by thesis to meet his own physical intuitions between Einstein and Bohr during the 1930 omission), as anyone might in such a complex and philosophical likings. Lindley captures Solvay conference, reactions to the Einstein– tale. Yet the story is told with verve, has some the passion of the struggle, showing both the Podolsky–Rosen paradox and an update on interesting historical asides, and makes a good public controversies and the sometimes harsh Schrödinger’s cat. Other sections also mention read. Still, you might not want to believe it; private judgements (for example, writing to a few sociological and philosophical reactions, well, certainly, not all of it. ■ third parties, Heisenberg and Schrödinger which Lindley criticizes and quickly dismisses, Arthur Fine is in the Department of Philosophy, each described the other’s work as repulsive, along with any dissent from the orthodox view. University of Washington, Seattle, and worse). These sections are disappointing. It seems, Washington 98195-3350, USA. What elicited this passion is the question of whether the behav- iour of atoms (quanta) can be described continuously in space and time. Heisenberg’s strange matrix methods are driven by his belief that they cannot, whereas the wave approach opens up the possibility that they can. That prospect, and the divisive reaction to wave mechanics, was bolstered by a development that Lindley scarcely mentions. It concerns ARCHIVES VISUAL EMILIO SEGRE EHRENFEST/AIP P. Louis de Broglie. Lindley does mention de Bro- glie, but describes his brilliant association of waves with particles as merely an “elementary idea that crossed his mind”. This is a stab- in-the-dark history that rips the important de Broglie relations from their theoretical context. That context was de Broglie’s pro- Niels Bohr (left) and Albert Einstein sought to shape the development of quantum physics in 1930. 376.

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