24/06/2017

Hitler's Uranium Club (1996) by Heisenberg, Hahn, Harteck, Wirtz et al




There are few, if any, other instances in recorded history where we have the conversations of leading figures as they complete one era, come to terms with it, and prepare their strategy for the next. It is as though these men were lifted out of history at a crucial turning point—from the age of conventional weapons to the nuclear era — placed within a timeless container and told to discuss their past and future as the recorders roll.
— Jeremy Bernstein


Astonishingly dramatic; also as pure as primary sources get. The result of months of secret eavesdropping on the German nuclear scientists, including after they hear of Hiroshima. Innocent of the microphones, the men concede their ignorance without ego, their character without any obfuscating propriety. (There are still two impurities: their words are both transcribed and translated by strangers. The physicists speak to us here in full sentences, with little of the fragmentariness and repetition of real speech. And it takes someone as highly trained as Bernstein to get us over the technical barrier.) Even so, this is as plain and self-interpreting as history gets. For six months they play madlibs, argue, and run around the garden, while the English and we listen in.

Hahn is a sweetheart and von Laue a droopy hero. The Party functionary Diebner is comic, even though he has most responsibility for the Nazi weapons project. Harteck is the most technically astute by far: he guesses a huge amount correctly, all in the teeth of loud ignorance by his more prestigious peers. von Weizsacker is the slimiest. Heisenberg is just weird: he has a very faint echo of the strange clear-sight-and-moral-vacuum of Eichmann. Enormous intelligence and no sense.




The morality of their wartime actions does not come up very much (except when raised by sweetheart Hahn or von Laue). They are mostly glad of the destruction of the Nazis, and Wirtz is horrified by the scale and singularity of SS murder. But the rest are more self-regarding than pro or anti Nazi. (Again, it is wonderful to read these and actually know they meant it.)

(What about the morality of our reading the reports? I don't have a clear opinion, but doing so after their deaths seems mostly fair.)

They very often speak about money, Heisenberg in particular. (Not just research funding or aid for their families in Occupied Germany, but dolla dolla bills.) On hearing that Hahn had won a Nobel:
"it says that you are supposed to receive the Nobel Prize for 1944." The excitement that struck the ten detainees at this moment is hard to describe in a few words. Hahn did not believe it at first. In the beginning he turned away all the offers of congratulations. But gradually we broke through, with Heisenberg in the lead, who congratulated him heartily on the 6200 pounds.





As you can see, Bernstein's editorial voice is a bit strong. But his other qualities are huge and unique: he knew some of the protagonists personally, and worked on nuclear weaponry himself. He is out to get Heisenberg, and overreads a few times. But this is because people (Powers, Frayn to a degree) persist in rose-tinting him: there's this idea that Heisenberg feigned incompetence at reactor-making as anti-Nazi activism. The transcripts make clear that he'd have made a bomb if he could, not because he is a Nazi or a German but because he was amorally curious, and hungry for primacy. Heisenberg does object to Nazism. But not very strongly.

Bernstein's conclusion is that the project was pretty much a shambles. They had a two-year head start on the Allies, but failed for several reasons: they had < 1% of the funding of the Manhattan Project, an unbelievably bad administration and communication of data and ideas, and key resources like deuterium kept getting bombed. But Bernstein feels able to go for the jugular:
reading this lecture, I am once again struck by the intellectual thinness of this group. Here are ten German nuclear scientists — nine if one does not count von Laue — who are supposed to be the cream of the crop, the intellectual elite, of German nuclear physics, men who had been working on these questions for several years. And look at the discussion it produced.

To see what I have in mind, let us entertain the following fantasy. Suppose the tables had been turned and ten of the best Allied scientists had been interned in Göttingen when a hypothetical German atomic bomb went off. Whom shall we include? Fermi, Bethe, Feynman, Serber, Wigner, von Neumann, Oppenheimer, Peierls, Ulam, Teller, Bohr, Frisch, Weisskopf... What would the technical conversation have been like? No doubt there would have been disagreements and some fumbling. But like this? The question answers itself.


Yet even with these handicaps, it seems Harteck could have built a basic pile in 1940, if the project was headed by someone less arrogant than Heisenberg. And that pile would have brought all the funding, and maybe sorted out their many collective muddles and lack of engineering care.






23/06/2017

Einstein (2007) by Walter Isaacson



Physics becomes in those years the greatest collective work of art of the twentieth century.

- Jacob Bronowski



What to say about the stereotypically great? Start by scrubbing off the accumulated century of journalism and appropriation.

Einstein's scientific achievements:

  • A model of Brownian motion: the decisive argument for the existence of atoms. His model enabled experimental confirmation of Dalton's theory, after a hundred years of denial or instrumentalism.
  • An elementary particle, the photon. The atomic hypothesis applied even to light.
  • A law for the photoelectric effect, implying a quantum theory of all EM radiation. (A realist about quanta, unlike Planck.)
  • So also lots of pieces of the "old" quantum theory.
  • A theory of light and so space and time, special relativity.
  • A flawed but progressive theory of heat capacity, the Einstein theory of solids
  • A better method of analysing quantum systems, "EBK". An ignored semiclassical precursor to quantum chaos theory.
  • The greatest scientific theory, General Relativity. Explaining gravity and, so, the shape of the universe.
    • Implies the first modern cosmology
    • Gravitational lensing (confirmed 1998)
    • Inadvertently predicted dark energy.
    • A crucial experiment: gravitational waves. (Confirmed 2015.)
    • Implies a whole lot more like black holes but you can't name everything "Einstein thing".
  • A general method for thermodynamics and information theory: Bose-Einstein statistics.
  • New state of matter: the Bose–Einstein condensate
  • Fruitful failed theory: first local hidden variable theory
  • A profound phenomenon, quantum entanglement. (Susskind calls entanglement "Einstein's last great discovery", though he 'discovered' it by trying to reductio away Copenhagen interpretation, taking entanglement to be a disproof.) (Confirmed properly 2015.)
    • A crucial experiment for a metaphysical principle, local realism is false!: EPR
    • Inadvertently, a physical constraint on metaphysics: nonlocality.
  • Thought-experiment: The content of the "Schrödinger's" cat setup
  • Repostulation of wormholes. (Not confirmed.)
  • Isotope separation methods for the Manhattan project.
  • Also a nontoxic fridge

Besides his own prize, confirmations of Einstein's theories have led to 4 Nobel Prizes (1922, 1923, 1997, 2001) so far, and first-order extensions several more (1927, 1929, 1933 at very least). We should expect a few more, for grav waves and not inconceivably for wormholes, some day.


Isaacson, like most people, portrays Einstein's post-1935 work as a dogmatic waste - he spent about thirty years straining to produce a field theory that could get rid of the spookiness and probabilism of QM. If you compare the output of the first half of his life to the second, sure it looks bad. But he was giving classical physics (determinism, continuousness, simplicity, fierce parsimony, beauty-based reasoning) a well-deserved last shake.

Imagine the strength of will needed to maintain full-time effort over thirty years of failures, with your whipsmart peers all tutting and ignoring you. His unified field efforts are methodologically sort of like string theory: a hubristic search over mathematical forms without contact with the actually physical to help limit the formal space.

And he actually had a decent decision-theoretic argument for his doomed crusade:
When a colleague asked him one day why he was spending — perhaps squandering — his time in this lonely endeavor, he replied that even if the chance of finding a unified theory was small, the attempt was worthy. He had already made his name, he noted. His position was secure, and he could afford to take the risk and expend the time. A younger theorist, however, could not take such a risk, for he might thus sacrifice a promising career. So, Einstein said, it was his duty to do it.

People also try to attach shame to him for his wildly stubborn anti-Copenhagen crusade: years spent thinking up tricky counterexamples for the young mechanicians, like an angry philosopher. But I think he had a good effect on the discourse, constantly calling them to order, and leaving it clear, after all, that it is a consistent view of the evidence.

The only unforgiveable bit in his later conservatism is that he ignored the other half of the fundamental forces, the strong and weak forces, and for decades. Two forces was hard enough to unify. I suppose another point against his long, long Advanced Studies is that he could have done even more if he had helped push QM along; as late as 1946, Wheeler tried to convince him to join in. As it is we have evidence against the unified field: "Einstein failed".

***************************************************************************


Einstein is like Bertrand Russell, only much more so: even more brilliant, even more rebellious, even more politically active, even more aloof, even more relentless, even more neglectful of his family. (Russell, on hearing of relativity for the first time: "To think I have spent my life on absolute muck.")

Along with Pascal, Leibniz, Darwin, Peirce, Russell, Turing, Chomsky, Mackay*, Einstein is one of our rare complete intellectuals: huge achievements in science, beautiful writing, good jokes, original philosophy, moral seriousness. To have warmth too, as Einstein does abundantly, doesn't have much of a precedent. However much Einstein is misattributed vaguely pleasant, vaguely droll, vaguely radical statements, the fact is he actually was brilliant, pleasant, funny, radical. Believe the hype.


* The usual word is 'polymath', sure, but although we are mad keen on polymaths, their generalism is seen as a laudable extra, rather than the vital service I now think they alone can give: you want people who have proven they can discover truths to tackle your ancient ill-defined questions like beauty, justice, existence; you can't do good unless you know a great deal about the targets of your morals; you want the vast imaginative search over philosophical possibilities to be aided by what we actually know. (As the noted writer against scientism, Ludwig Wittgenstein put it:
Is scientific progress useful for philosophy? Certainly. The realities that are discovered lighten the philosopher’s task: imagining possibilities.
)

Maxwell, Boltzmann, Schrödinger, and Feynman are basically it: they are as good at writing and philosophy as physics, and very funny to boot, but they didn't push society forward much (...) Goethe tried admirably, but didn't achieve much science. Descartes should definitely be on there but eh. Hilary Putnam discovered important logical results and has all the other virtues, but I guess science is a stretch?. von Neumann covered perhaps the most intellectual ground of all of these people, but I'm not sure he had a moral or political life to speak of. Herbert Simon is deep and broad and fun. And Bohr is brilliant and moral but can't write.

(There's a lot of others I'd like to include, but won't because I know I'm a fanboy** / it is too soon to say: Scott Aaronson, David Pearce, Nick Bostrom.)


** A modern Moore's paradox: "I know I'm a fanboy, but my thinker is still better than your thinker."



***************************************************************************


One particularly charming bit in this book is Einstein's long friendship with the Queen Mother of Belgium. When Szilard warns him that nuclear fission has been achieved and could give the Nazis dominion over all, Einstein's first thought is to ask Elisabeth to sort it out, by grabbing all the Central African uranium and sending it far from the Nazis. (As it happens, the Uranverein got their uranium from Czechoslovakia.)

***************************************************************************


Ahead of his time morally (still is):

  • Denounced WWI as the senseless crap it was.
  • Never went to the Soviet empire (despite repeated invites).
  • Denounced the Nazis from '31, despite/because of public threats to his life.
  • Flipped from pacifism at the right moment.
  • Many early actions for US civil rights, including work against McCarthyism.
  • Sold his original manuscripts for War Bonds


Even his Zionism was enlightened (pro-migration, anti-state, anti-Begin):
Should we be unable to find a way to honest cooperation and honest pacts with the Arabs,” he wrote [Chaim] Weizmann in 1929, “then we have learned absolutely nothing during our 2,000 years of suffering.

He proposed, both to Weizmann and in an open letter to an Arab leader, that a “privy council” of four Jews and four Arabs, all independent-minded, be set up to resolve any disputes. “The two great Semitic peoples,” he said, “have a great common future.” If the Jews did not assure that both sides lived in harmony, he warned friends in the Zionist movement, the struggle would haunt them in decades to come. Once again, he was labeled naïve.

Isaacson read all the letters, formed a view on all the academic controversies (Maric's contribution, baby Lieserl, what sort of deist or Zionist or pacifist he was), and covers most of the papers, recasting the classic thought experiments very lucidly. This was a huge pleasure. Read with Wikipedia open, though: C20th physics and its physicists are way too deep and broad for one book.

4*/5.