Monday, August 12, 2013

Bohr's beginnings

Here’s a book review, of sorts (I was asked to write something more like an essay review) just published in New Scientist.


Love, Literature and the Quantum Atom Finn Aaserud & J. L. Heilbron Oxford University Press, 2013 ISBN 978-0-19-968028-3

Niels Bohr was one of the most profound thinkers among the early pioneers of quantum theory. He was the first truly to recognize and confront the philosophical problems that the theory posed, and the solutions he offered, such as the idea of complementarity and the Copenhagen interpretation, are still debated today. One hundred years ago he devised the first quantum picture of the atom, and he also anticipated quantum effects in biology.

What impresses most about Bohr’s scientific thought is that he could leave consistency to littler minds. Like James Clerk Maxwell, another genuinely deep physicist, he was happy to leave some matters unresolved and to accept contradiction. So what if the Bohr atom violates classical electrodynamics, which says it should decay? So what if wave can be particle? That’s just how things are (or how they seem, which for Bohr was much the same).

Love, Literature and the Quantum Atom is valuable for reminding us of this. But it’s a peculiar beast all the same, bearing signs of having been cobbled together for the Bohr atom centenary. In the first section, Finn Aaserud, director of the Niels Bohr Archive, offers a fresh perspective on Bohr’s early family life through newly released correspondence, especially with his wife Margrethe. Then the science historian John Heilbron, who collaborated with Thomas Kuhn in 1969 on a study of the Bohr atom, supplies a new account of the development of that seminal work in which he considers Bohr’s interests in literature, particularly that of Goethe and Ibsen. Finally the book reprints Bohr’s three-part paper (the so-called “Trilogy”) from 1913, “On the Constitution of Atoms and Molecules”.

To link Bohr’s extra-curricular reading with his science, Heilbron has been set a more or less impossible task. At times he can pursue it only by finding apt quotes from Ibsen’s Peer Gynt or Goethe’s Faust with which to punctuate Bohr’s professional life, irrespective of whether Bohr himself had the words in mind. Heilbron’s account of Bohr’s scientific journey is as insightful and informative as we’d expect from him. But once we get to the equipartition principle and the Balmer series, Goethe doesn’t have much to add.

This experiment fails not because a scientist’s interest in arts and literature can tell us nothing about his or her science, but because it seems Bohr’s cannot. He read widely and thought deeply, but on this showing was addicted to the strain of Germanic-Nordic romanticism that today looks like sentimentality, even chauvinism: great men striving to be great, while their pure-hearted, maidenly lovers pledge placid and dewy-eyed support. Margrethe was in fact Bohr’s staunch and sometimes steely ally, as he knew and appreciated – which is why all his talk of “my little one” who he would (using Ibsen’s words) “lock away as heart’s treasure” makes you realise why modernism and Virginia Woolf were so badly needed.

In a soul as noble as Bohr, this kind of sentiment has its touching aspect. But it’s not hard to see why, for less principled men, these visions of struggle and destiny, of heroes and Vikings, led down darker paths. It’s not too much to suggest that this was a Germanic thing (including Dutch and Danish – as physicist Hendrik Casimir attested, in the Netherlands too the intellectual elite was saturated in Germanic Kultur). There’s no inevitable path from Goethe to Goebbels, but the notion of Bildung – the particularly German character development all professors had to undergo – did breed the sort of patriarchal and patriotic conservatism that, as Heilbron showed in his splendid biography of Max Planck (The Dilemmas of an Upright Man, 1986), made it all but impossible for the traditional academics to muster any resistance to the Nazis.

This is why I’m left with mixed feelings about this glimpse at Bohr’s hinterland. On the one hand it is refreshing to see a great scientist being passionate about a difficult philosopher like Kierkegaard instead of coming up with empty soundbites about philosophy being dead. On the other hand, such an education evidently did little to build a moral framework; those few who, like Bohr and Max von Laue, behaved with something approaching heroism in the face of Hitler did so from some inner reserve of integrity that drew little on their broad education. Their generation was in this respect neither better nor worse than the culturally unsophisticated Feynman or the later generations brought up on Star Trek, Star Wars or Tomb Raider. Whatever it is that makes truly noble and responsible (let alone successful) scientists, it isn’t great art.

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