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In his massive book Heisenberg's War: The Secret History of the German Bomb, Thomas Powers says that Heisenberg, who never became a Nazi and balked at the immorality of building a bomb for Hitler, did what he could to guide "the German atomic bomb effort into a broom closet." But Powers also knows that the evidence is not conclusive and that Heisenberg, who lived until 1976, did little to clear things up.

I'm not well informed on this story.

Question is, did Heisenberg undermine the German atomic bomb by deliberately hiding his expertise from the Nazis?

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Whatever the actual role Heisenberg played, "boycott" is not quite the right word - willing or unwillingly, effectively or ineffectively - he did participate in the atomic program. –  Felix Goldberg Apr 26 '13 at 7:17
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4 Answers

The argument for Heisenberg being intentionally incompetent is that he made two "incorrect" choices in which path to follow.

  1. He selected heavy water as the reactor moderator, even though it is very unusual and requires a big plant to make it.

  2. He selected plutonium as the fissile material, even though it doesn't occur in nature and have to be created in nuclear piles.

The argument is that Heisenberg, being a highly intelligent man, would not have made those mistakes, and that he therefore intentionally made those choices to delay or stop Germany from getting the bomb.

However, this ignores that Heisenberg was a scientist, not an industrialist. I think Heisenberg simply chose the options he thought had the greatest chance of succeeding. He didn't think Uranium was a good candidate for a chain reaction, and that it would be easier to make a bomb out of Plutonium. He also thought it would be easier to create a nuclear pile if it was moderated by heavy water.

He was definitely correct about the heavy water. Making a heavy water reactor is easier than a graphite or ordinary water reactor, and in addition, a heavy water reactor can work with un-enriched uranium. This means that although you need facilities to create heavy water, you don't need facilities to enrich the uranium, to some extent compensating for the need of heavy water.

And it's hard to claim that he was wrong with regards to Plutonium. He rather was "too correct". The Manhattan project decided to pursue both Plutonium and Uranium bombs, and during the development of those bombs they had to come up with a more complex bomb design for the Plutonium bomb, because Plutonium turned out to be so reactive that it would probably explode to early in the process, making it likely to "Fizzle" if it had been used with the original simpler design, while the simple design could be retained for the Uranium bomb.

So I think he rather chose the options that was the easiest for him. The "safe bet", so to speak. He probably either underestimated the time and effort required in creating enough heavy water and then enough plutonium to build a bomb, or he didn't make his choices with regards to the time frame at all, but based them entirely on what he thought would be easiest, as opposed to what would be quickest.

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No, he did not.

He very much wanted Germany to win the war. For example he was very excited about the offensive in Ardennes. He met with Neils Bohr in attempt to gain more information about his work, which was described by Bohr himself.

The source of this information is the Neils Bohr's biography by Daniel Danin http://reeed.ru/lib/books/nils_bor/

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WH's account of the meeting is very different. He claimed to be trying hint to Bohr that the Germans had made very little progress - in the hope that the allies wouldn't use the weapon on them. Bohr, who wasn't familiar with the details of the bomb project at the time, misunderstood it to be WH saying that Germany would soon have a bomb. WH deeply admired Bohr and was very upset at the outcome of the meeting. (WH autobio quoted in Richard Rhodes book) –  none Oct 6 '13 at 17:25
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J. Robert Oppenheimer's biographer Ray Monk thinks that Heisenberg played no such role (perhaps he "did" in convenient-to-some retrospect). See also here.

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We know several things about him. First, Heisenberg was notoriously "incompetent," insofar as there were major gaps in his understanding of atomic physics. Second, he recognized this fact, and went to his old professor, Niels Bohr, to ask questions to clear up things that he was unsure of in his own mind. (This visit was the subject of a play.) Third, we know that Bohr did not answer Heisenberg's questions, and fourth, we know that Heisenberg did not resort to "extralegal" methods to find the answers (such as taking up the Gestapo on their offer to torture the answers out of Bohr.


From what anyone can gather, Heisenberg was an ethical man. That did not preclude him from "rooting" for Germany, he was German after all, but on the other hand, he seemed to want Germany to win "fair and square," rather than "at all costs." The best guess is was that he would have preferred Germany to win, but was "reconciled" to its losing. In any event, he apparently tried to help Germany win the war, but only in a "moral" way, and not "outside the rules."

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What do you mean that he wanted to be ethical? The fact that he did not order to torture Bohr does not mean he was ethical. The reasons may be that he felt Bohr as a friend or guru, because torturing Bohr would make international resonance, because he was unsure that Bohr had the needed info, because he did not want gestapo to intervene and so on. Heisenberg definitely wanted a nuclear bomb, was it ethical or not. -1 –  Anixx Apr 26 '13 at 11:47
@Anixx - be careful - Tom Au did not say that he "wanted to be ethical"; you may have your own opinion on this but you're falsely putting words into Tom Au's mouth here. –  Jimmy Shelter Apr 28 '13 at 19:08
Heisenberg was notoriously incompetent ? It's like saying that "Columbus was a notoriously bad sailor"! He was one of the "founding fathers" of quantum mechanics, which encompass atomic physics. The major gaps you speak about are from the 1920s, and everyone had them at the time. His visit to Niels Bohr (another "founding father") helped clear the matter. By the time of the war, all this physics was clear, and Werner Heisenberg (along with others, including Bohr, Eintein, Ferni, etc.) . –  Frédéric Grosshans Jun 14 '13 at 14:47
I put the word "incompetent" in quotes because it was a "relative" (compared to Einstein, Fermi, and Bohr) level, not absolute. Heisenberg did win a Nobel Prize for quantum mechanics, after all, making him better than "most." But by your own answer on another question, German scientists (including Heisenberg) "did not thought about the concept of critical mass, and vastly overestimated the amount of enriched uranium needed to make a bomb." –  Tom Au Jun 14 '13 at 17:55
@Anixx If you're a moral or cultural relativist, being in an evil society and not using the evil options freely available to you, qualifies as ethical. Not exactly pro-active, but considering the cost of civil disobedience at the time... –  LateralFractal Oct 6 '13 at 0:54
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