Book Reviews - Review 245

Wolfgang Pauli was one of the greats of twentieth-century physics, the original postulator of both particle spin and the neutrino (a chargeless particle produced by atomic decay). He was also a somewhat controversial figure, humorously blunt in his criticisms of colleagues, and in the latter half of his career entertaining ideas about the relationship between physics and psychology that more conventional scientists have found hard to take seriously. The author of this book argues that biographers have shied away from him as a subject, deterred by the quasi-mystical ideas that he devoted a great deal of his mental life to contemplating.

Brücken zum Kosmos is not the comprehensive biography of Pauli that has hitherto been lacking: rather, it is a free-form study of his scientific and philosophical thought. Looming large over Pauli's thinking is the influence of C G Jung, his colleague at Zürich University and the man who persuaded him that there might be a deeper level to reality than physics could hope to explain. Jung introduced Pauli to the idea of mental archetypes, and awoke in him a fascination with the subconcious that one can infer was always latent in his contemplative, inward-looking personality.

In retrospect, Pauli's fascination with the sometimes meretricious ideas of Jung might seem naive. Jung was, in my view, onto something with his notions of the collective unconscious, and the "acausal connecting principle" that he named synchronicity. However, his obsession with grouping phenomena into four-way categories is more schematically satisfying than it is genuinely enlightening. Certainly there is something intriguing in the fact that in several areas of physics, a fourth principle ("das widerstrebende Vierte", as Jung neatly put it) sits uneasily with the other three: time with the three dimensions of space; particle spin with the more tangible qualities of position, momentum and mass; gravity with the other three fundamental forces. But both Jung and Pauli seem content with the idea that there is something irreducibly, mystically significant about certain numbers, and don't (at least as far as one can infer from Fischer's book) go so far as to consider whether there is something fundamentally aribitrary - though not necessarily invalid - about all symbols and archetypes, whether they are sensory or numerical.

Pauli was reticent in public about his psychological and philosophical interests, aware of the damage to his reputation that accusations of mysticism might bring. He maintained that rationality should never be abandoned, and, while Eastern ideas interested him, he rejected their view of reality as fundamentally fluid and intangible. He believed that the challenge of Western thought was to find a "middle way" between science and mysticism; yet isn't that very idea of "a middle between two opposites" an essentially analytical, Western one? Eastern thinkers would, I feel, argue that there is no middle: that understanding comes not from reconciling opposite concepts but from contemplating them together in all their intriguing irreconcilability. And in fact, this irreconcilability of concepts in phyics seems to be what drew Pauli to his extra-physical interests in the first place: the more precisely you know about one quality of a particle (e.g. momemtum), the less precisely you can know about its complementary quality (e.g. position).

Part of Pauli's public message was the rejection of the idea of the paranormal. Perhaps this was, again, a defensive gesture to counter his interest in Jung's idea of synchronicity. It is particularly at odds with the "Pauli Effect": Pauli's apparent ability to break technical equipment by involuntary telekinesis. One colleague refused to allow Pauli in his laboratory, so reliable was this phenomenon; examples of the Pauli Effect abound, and Pauli himself believed in it. He attributed it to a paradoxical technophobia lodged deep in his subconscious, and attested to a feeling of tension before equipment broke, and strange relief afterwards.

A picture emerges of Pauli as a quirky and arch, but introspective individual, who, like most of the great pre-war physicists, was never satisfied with glib statements of certainty about the nature of things. (How different these modest European minds were, one feels, from the cocky American ones that came to the vanguard of theoretical physics after the War.) One feels that, if he was led a little astray by the charismatic Jung, both men were on the right track in trying to re-accommodate the idea of the irrational into Western thought.

As for Fischer's book: it's readable and informative, but very much a guide to Pauli's intellectual development rather than his personal life. The material is not presented in a particularly organised fashion, and in the early chapters the author jumps back and forth in Pauli's life in an irritating way. Fischer is not as critical of Jung's sometimes arbitrary schemes as he might be. However, he shows a genuine appreciation of the importance of Pauli's intellectual endeavour, and of the depth and subtlety of much of his thought.