02 June 2013

Book Review: A Sophisticate's Primer of Relativity

A Sophisticate's Primer of Relativity, Second Edition, P.W. Bridgman
ISBN: 0486425495

I picked this book up in a bookstore mainly because I'm interested in learning more about relativity. Relativity is a key theory of physics over the last 90 years, so I figured I should learn a bit more about it than my basic understanding of it. When I saw the title, I figured that this would be a good book. Hey, I'm mathematically 'sophisticated' and this is a primer, so it seemed a perfect fit.

This will teach me to read a few pages of a book before I buy it. (In this case, my husband was standing around, waiting for me to join him at the checkout, so I felt a bit rushed to either keep it or put it down.) While relativity is the subject, it's not a primer and I'm not sure that even most physicists would find it useful.

Problem #1: The book was originally published 1962 and then reprinted. This second edition was done in 1983, but only the introduction seems to have been updated. (Admittedly, the author died in 1961, so he really couldn't update it.) Some of the comments and discussions seem very dated, such as the discussion on 'ether'. I don't think many people born after 1950 even know what ether refers to, except for the gas used to put people out during surgery. That's not the same ether.

Problem #2: Despite the title, the author assumes one is familiar with the theory of special relativity, the general theory of relativity, and many of the 'supporting' theories. Reichenbach, Bunge, Maxwell, Lorenz, etc., may all be familiar names to the author, I have very little idea who they are are (Maxwell, I have heard of), let alone what their specific theories refer to with regards to relativity. One or two small lines of background would have gone a long way to help non-physicists read this. The author does the same thing with the theories -- he refers to them and discusses problems with specific equations generated from the theory, but never gives the equations.

Problem #3: The author makes strange claims with no support. For example, he questions whether causally connected events must occur be related invariably in time. This breaks down to mean if A causes B, then A doesn't necessarily have to occur before B. A can occur after B, but A can still cause B. I spent many days thinking about this, but I still don't get it. Had he provided some support or examples, I might have been able to figure out what he was getting at, because I can't believe that he's saying A causes B but B precedes A.

Problem #4: The author seems much more interested in the philosophy of physics and the minutiae of the theory, than in any implications of the theory. For example, he spends pages on discussing how to set 2 clocks, or whether 2 observers are necessary. While this is interesting to some degree, I got the impression that this was all he could say on the subject. (People do tend to pick at the edges of theories, rather than attack the heart of the theory, if they don't understand the theory fully.)

Problem #5: The author's writing style is difficult. I do understand that he is trying to be precise and that I may not have sufficient background to understand each term he uses in the precise way he uses it, but still, his writing often was unclear. My guess is that his writing is more in line with 1930 philosophers than 2000 physicists.

Overall, I did learn a few things about relativity, but not as much as I had hoped I would. I'll need to find myself another primer on relativity to begin to understand it. Then maybe I'll come back to this book and see if I have changed my mind about it.

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