Monday, 6 October 2008

Einstein’s Mistakes – Hans C. Ohanian ****

This is, without doubt, one of the most fascinating popular science books I have ever read. When I first saw the title, I was filled with dread, because the bookshelves are filled with crank titles that try to take on Einstein and prove him wrong. But this is quite different. It’s a carefully constructed exploration of Einstein’s life and scientific work, built around the errors in his work that are often glossed over in presenting the triumph of his great ideas.
The only slight concern about the approach is that this does result in a rather smug feel to the book, a sort of ‘aren’t I clever, I can tell you where Einstein went wrong’ aura that isn’t helped by occasional descents into loose language (apparently Van Gogh became a great artist ‘when he went bonkers.’) Building the book around Einstein’s mistakes is an excellent idea, but sometimes it results in excessive weight being put on a relatively small point, such as an assertion in the original Special Relativity paper that allegedly drove a lone yachtsman mad.
However there certainly is a wealth of material here that I have never seen before, or not seen presented anywhere near so well. We see some historical examples of error that don’t get enough mention, such as Galileo’s strange idea that the tides were caused by the rotation of the Earth, or Newton’s fudged experimental values which somehow managed to match his theoretical predictions exactly, even when he got those predictions wrong.
Perhaps the best example from Einstein himself was a wonderful mistake called the Principle of Equivalence. This was the idea that started him on the stunning ideas about curved spacetime that lie beneath general relativity. I have often seen this principle, stating that a gravitational field and acceleration are equivalent, so in a closed box you couldn’t tell if you were feeling gravity or being accelerated (say by a rocket), used to introduce general relativity, just as Einstein did. Unfortunately this principle is flawed. It was the inspiration behind general relativity, but it happens to be wrong. Now that is interesting!
My biggest worry about the book is that in the one aspect of Einstein’s work I do know in a lot of detail, the EPR paper of 1935, Hans Ohanian gets things horribly wrong. He seems to think that the paper’s arguments against quantum theory are based on the uncertainty principle, a common mistake because the paper mentions both position and momentum. But mistake it is. In fact Einstein later emphasized this, commenting that his attitude to the use of position and momentum was ‘Ist mir Wurst’, literally ‘is sausage to me’, or approximately ‘I couldn’t care less.’ Either of the measurements was sufficient, because the argument is nothing to do with uncertainty. Now it’s an easy enough mistake to make, as it has been made by several other books – but it does throw some doubt on whether any of the other assertions about Einstein’s mistakes are equally flawed. I’m inclined to give Ohanian the benefit of the doubt.
Whatever, it is an intriguing book. It’s probably best left to those with some previous experience of physics, at least to high school level, because the details of the errors can be quite subtle – but it’s well worth the effort. Recommended.
Hardback:  
Review by Brian Clegg

No comments:

Post a Comment