P. W. Bridgman (1) (1882–1961)

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… (plus d'informations)

«Ci sono tecniche particolari dell'essere intelligenti. Non è facile acquistare una padronanza esatta degli strumenti mentali che abbiamo ereditato a nostra insaputa o che sono intrinseci alla struttura del nostro cervello. Per far questo sono necessari uno sforzo metodico e una lunga pratica. La conseguenza più importante della rivoluzione concettuale verificatasi nella fisica per opera della relatività e della teoria dei quanti non consiste in dettagli come la contrazione dei regoli in movimento, ma nella scoperta che prima non avevamo fatto un uso corretto delle nostre facoltà intellettuali e che è importante sapere come realizzare tale uso. Il fisico ha ormai trovato una maniera abbastanza soddisfacente per trattare i significati delle parole che usa [...]. Questo metodo è stato da me chiamato "operativo", e consiste essenzialmente in questo: che per conoscere adeguatamente il significato di un termine dobbiamo poter descrivere ciò che facciamo quando lo usiamo. È mia convinzione che questa maniera di trattare i significati abbia un'applicazione più vasta a tutto il nostro linguaggio, nella misura in cui esso è un'attività dell'intelligenza».

L'autore:
Percy Williams Bridgman (1882-1961) è noto per l'elaborazione del «metodo di analisi operazionale». Nel 1946 ricevette il premio Nobel per la fisica «per l'invenzione di apparecchiature per ottenere pressioni molto elevate, e per le scoperte fatte mediante esse nel campo della fisica delle alte pressioni».… (plus d'informations)