Anderson's primer on the purpose of theory, research sociology, and solid state history

I highly recommend Phil Anderson’s More and Different: Notes from a Thoughtful Curmudgeon to anyone interested in solid state physics, or the history and sociology of physics in the 20th century more broadly. It is a compendium of different pieces written at different stages in his career - a mix of book reviews, notes for talks, and essays.

First and foremost I found it an immensely enjoyable read, packed with whimsy and enthused with what I can only assume was a profoundly strong interest in nature and the practice of science. Surprisingly, it goes a long way to humanise Anderson, something it can be easy to lose a grip on when studying condensed matter physics even today, which I found endearing and, frankly, a little comforting. See, for example, his early work on super-exchange in collaboration with Charlie Kittel.

Having come to solid state physics without a traditional grounding in undergraduate physics, I realise now that I may have lacked a more historical treatment of the subject. For example, his account of the history of superconductivity up to the BCS paper, and subsequent developments up to Josephson, was new to me. Not so much the content, but the context. I’m not going to sit here and delude myself into thinking the developments arose anywhere near as elegantly as they seem on the page, and to his credit Anderson also emphasises this multiple times, but I have a feeling that it is useful somehow, philosophically and as a guide of personal research taste and value, to have a clear hindsight understanding of which experimental anomalies led to which developments (even if a large amount of data is lost to the survivor bias).

Anderson writes about a great deal of topics though, not just the history of superconductivity. Some personal highlights in no specific order:

• ‘Some thoughtful words (not mine) on research strategy for theorists’ and ‘BCS and me’ - Anderson discusses some views of Francis Crick on what good theory is and how a theorist ought to interact with experiment. This struck me, particularly the idea of ’theory as demonstration’, or theory as proof of concept.
• ‘The quiet man of physics’ - I’ll admit to knowing next to nothing about John Bardeen before this, except for the work which made him, but I got a taste both in this book review of Anderson’s and in his earlier chapter on the history of BCS. Nothing extraordinary in this chapter specifically but I note that I’m intrigued by his approach to physics and am motivated to read the therein referenced biography.
• ‘Solid state experimentalists: Theory should be on tap, not on top’ - Another essay on Anderson’s views on what constitutes good theory and how it should relate to experiment, with a focus on the dangers of theory-led research. I find these kinds of discussions incredibly interesting and important.
• ‘Good news and bad news’ - Written 6 years into the high-Tc program, it’s something of a rant about the sociological state of the direction. Remaining firmly optimistic about scientific progress, Anderson lambasts the practitioners at large, both in their practice and motivation. To be fair to him, he acknowledges that the contemporary situation did not emerge out of a vacuum (not intended), but results from an increasing need to act in a way that is motivated more by careerism than by a desire to have a correct understanding of nature.
• He has a couple of points on the cognitive dissonance which solid state physicists (or physicists generally) suffer from which I found quite thought provoking. He gives the examples of electronic band structure together with d/p bands, and condensed phases together with the Ergodicity hypothesis.
• ‘Nevill Mott, John Slater, and the magnetic state: Winning the prize and losing the PR battle’ - A fascinating account of the early theory of anti-ferromagnetism, and the ‘battle’ between Mott driven insulating physics and the Slater insulator, where the formation of AFM order itself drives the opening of a band gap. This is something which I’ve had to clarify a few times in the course of my own research and so I found it fascinating to learn how the discourse evolved over the years. While reading about how each of their theories interacted with the experimental findings, I was again brought back to the ’theory as demonstration’ notion of Crick. Interestingly, the ‘failed PR battle’ was perhaps a reasonable complaint at the time, I wouldn’t say it’s true today.