Free Radicals - Michael Brooks [31]
That careful phrasing must have been a knife in the back to Eddington, but it seems fair. Even in 1962, when a team of astronomers tried to reproduce Eddington’s findings during an eclipse, they failed – despite having better equipment. They concluded that it just couldn’t be done. Small wonder, then, that many of Eddington’s contemporaries remained sceptical about the ‘evidence’ for Einstein’s theory. In 1923, one commentator summed up the situation:
Professor Eddington was inclined to assign considerable weight to the African determination, but, as the few images on his small number of astrographic plates were not so good as those on the astrographic plates secured in Brazil, and the results from the latter were given almost negligible weight, the logic of the situation does not seem entirely clear.
So what did Einstein make of Eddington’s work? Did he suggest we await less controversial confirmations of relativity? Of course not. Einstein was the anarchist-in-chief.
Einstein ‘knew’ that he was right before the confirmation. His friend Heinrich Zangger, a professor of pathology at Zurich, heard about Eddington’s results and wrote to Einstein: ‘Your confidence … that light would have to go bent around the Sun … is for me a tremendous psychological experience. You were so certain, that your certainty had an overwhelming effect.’
It may even be that Einstein never bothered to find out exactly what Eddington had seen. Einstein was certainly cavalier with the facts about Eddington’s work: writing to Max Planck, he declared that ‘the precise measurements of the plates yielded exactly the theoretical value for the deflection of light’. This was, as we have seen, not true. But it is not clear that Einstein was deliberately misleading Planck. Einstein was simply not terribly interested in data.
Genius that he was, this was an attitude that served him well. In 1905, for example, his ideas on special relativity did not fit with the available data on how electric and magnetic fields deflected beams of charged particles; instead, it confirmed a rival theory. But Einstein would have none of it. He declared that the competing theories were inadequate when faced with other kinds of experimental results and ‘should be ascribed a rather small probability [of being right]’. He was absolutely correct: a little while later, more accurate measurements showed that special relativity was the better theory.
Einstein once told the German theoretical physicist Werner Heisenberg that it would be ‘quite wrong to try founding a theory on observable magnitudes alone. In reality the very opposite happens. It is the theory which decides what we can observe.’ That thinking seems to be behind this statement of Eddington’s:
Observation and theory get on best when they are mixed together, both helping one another in the pursuit of truth.It is a good rule not to put overmuch confidence in a theory until it has been confirmed by observation. I hope I shall not shock the experimental physicists too much if I add that it is also a good rule not to put overmuch confidence in the observational results that are put forward until they have been confirmed by theory.
In science, anything goes. Or does it? Perhaps, by focusing on a few celebrated scientists, I have been guilty of doing my own cherry-picking. To claim from these cases that science is anarchic, and that it does not enslave itself to the results of experiments, is all very well. But does the claim stand up when applied to everyday science? Yes it does.
Perhaps the most compelling evidence for modern, everyday scientific anarchy came in 2006, from grass-roots interviews carried out by the team