Sunday, 12 July 2009

Remembering Emil Rupp

In the "impossible diamond" post, when I was talking about the impression given by C20th physicists had that fraud didn't happen in their profession, I forgot about Emil Rupp. Then again, almost everyone tends to forget about Emil Rupp.

Emil Rupp (1898-1979) studied under Nobel-prizewinning experimenter Philipp Lenard, and was considered by some to be one of the most exciting experimenters of his time. He did a series of experiments related to effects like electron diffraction that caught the imaginations of a number of key theoretical physicists, and his work was sometimes credited with being one of the most important influences on the development of quantum mechanics.

Rupp's work was central to some key questions in quantum mechanics. What is reality? is light really a wave or a particle? Is it emitted continuously or instantaneously? Can a state that is said not to exist still influence the outcome of an experiment?

Ironically, it then turned out that Rupp's own experiments, which had been so influential, didn't seem to have existed either. The thing supposedly came to light when some of his colleagues visited the lab where Rupp was working and confronted Rupp – he'd been describing experiments with 500kV electrons, but wasn't in possession of an accelerator that went up to 500kV. He'd been making up his experimental results.

Why did Rupp do it? Well, like Bernie Madhoff, for a while he was getting away with it, and was having a very, very good time. He was identifying problems that the physics community wanted solving, and solving them (albeit with fake experimental writeups). He was an enabler, and people (other than the fellow experimenters that he kept leapfrogging) liked him for it. Great names in theoretical physics would seek him out and cite him. Einstein spent quality time corresponding with Rupp in 1926, working through issues with wave-particle duality, and trying to work out what should happen in certain experiments ... and trying to come up with explanations for how it was that some of Rupp's experiments had come out so well, given some of the difficulties that he should have come up against. The collaboration was reasonably well-known, and people started referring to the "Einstein-Rupp experiments".

When the game was up, Rupp found that he'd now given the physics community a new headache. He'd shown that peer review didn't work as an efficient way of identifying "friendly" fraud within the system. If you had the right background, and you worked out which results people wanted and published those results, your paper tended to pass peer review unless the referees were so convinced that you couldn't possibly have gotten those results that they called you on it. And if an experiment produced the expected result, it was difficult for a referee to insist that an experiment was too successful. Results that don't agree with current thinking can be summarily rejected by peer review on the grounds that getting a "wrong" answer amounts to apparent evidence of error, but rejecting results that give the "right" answer is more awkward.
The lesson seemed to be that if you wanted a career as a scientific fraudster, the way to succeed was to agree with whichever theories were currently in vogue. So the physics community was now facing a potential upheaval – how would they assess how many other key papers by respected researchers might have been unreliable, or even outright fakes?

Rupp solved that problem for them with another piece of documentation. He sent a retraction of his five key papers, along with a letter from his doctor stating that Rupp had been in a "dreamlike" mental state when he'd written them.
It was a tidy conclusion – Rupp exited physics without there having to be a nasty inquiry, the community got to draw a line under the affair, quickly, and thanks to Rupp's explanation, they got to write off the matter not as an extended period of fraud lasting nine or ten years, but as the unfortunate actions of a guy who was having some mental health issues. That let the community off the hook – if Rupp hadn't been completely sane at the time, then we could still tell ourselves that physics was a special "fraud-free" field of science, and that no sane physicist would ever commit fraud. So everything was okay again.

Was Rupp's doctor's letter genuine? We didn't really care. We had the result that we wanted.