|(βmc2 + c(α1p1 + α2p2 + α3p3)) ψ(x,t) = iℏ||∂ψ(x,t)|
I quite often pass the spot where this picture was taken (the building is now a school, just beside the European Parliament) and if I am with someone I tell them the story of how the universe was reshaped there, 87 years ago. (Incidentally I caught Farmelo out on a point of Brussels geography - he says that the conference delegates were staying at the Hotel Britannique "near the site of today's European Parliament", but in fact it was on the western corner of Place du Trône, much further from the future European Parliament than the conference venue.)
Farmelo does his best to explain the inexplicable: how a chap from a fairly modest background, with no family history of contributions to science, was able to revolutionise how we think about the fundamentals of existence. It's an interesting effort: Dirac had several good ideas in his lifetime, some of which were timely and some only later recognised as such; his most implementable idea was separating out uranium isotopes by gas centrifuge, which is bizarrely practical in comparison with his theoretical innovations. Farmelo argues that Dirac was uniquely qualified to think of this because of his early training in engineering, but it seems more of an anomaly than part of a pattern in his account. Really the most interesting thing is that Dirac was driven by a concept of and commitment to mathematical beauty, and that gave him a lot more hits than misses. There's also quite a lot about the political connections of the nuclear physics community in mid-century; Dirac comes across as not particularly ideological, but fiercely loyal to his few friends, with little patience for political sectarianism, and generally more left than right in his sympathies.
Dirac was famously difficult as a person. Here he is writing to his future wife:
Dear Manci,Gawd, poor Manci!!! But she married him anyway, and they had two children together as well as bringing up her two from her previous marriage. She was Hungarian; Farmelo speculates toward the end that many autistic men form successful relationships with partners from different cultures, who go into it expecting to have to work harder at communicating than perhaps someone from the same background might do. I'm sure that, like me, you can immediately think of plenty of examples - and counter-examples - of this proposition. (The relevance of autism in discussing Dirac's personality goes without saying.)
Thanks for your 8th letter, which I received yesterday. It was a nice cheerful letter. You say I do not answer all your questions. I have read again your more recent letters and I give here the answers to the questions that I have not answered before.
letter number question answer 5 Have you seen Marietta's baby? No. 5 What makes me (Manci) so sad? You have not enough interests. 5 Whom else could I love? You should not expect me to answer this question. You would say I was cruel if I did. 5 Isn't Gabor a clever little fellow? Yes certainly, I expect so. 5 You know that I would like to see you very much? Yes, but I cannot help it. 5 Are you "Dear Dirac"? Sometimes. 5 Do you know how I feel like? Not very well. You change so quickly. 5 Were there any feelings for me? Yes, some.
This book won the Costa biography award in 2009, and I suspect was a worthy winner. Strongly recommended.