Casimir's Memoir

This post is a review of the popular science book Haphazard Reality by H.B.G. Casimir, first published in 1983. Casimir was a well- known Dutch physicist who made notable contributions to both pure (Casimir effect, Casimir invariant, Gorter-Casimir model) as well as applied (as Director of the Research Lab at Philips) physics. I re-read the book after many years, on prodding from a colleague, while I was visiting the Netherlands over the last two weeks.

Casimir's memoir is about his experiences in science and is valuable because he was in the thick of the action as quantum physics was being developed in early twentieth century Europe; and because he later moved to industrial research which had became important in the WWII years.

Casimir had an early start in life. His parents were both educators, fostered Casimir's curiosity, and made sure he received a very good education. Ehrenfest, who was professor of theoretical physics at Leiden, was a family friend, and eventually took Casimir on and gave him a PhD when he was merely 22 (during this time Casimir describes his interactions with Goudsmit and Uhlenbeck, who were students of Ehrenfest and established the existence of electron spin). Casimir also gives a detailed professional as well as personal account of Ehrenfest (who was Boltzmann's student), touched with admiration for his advisor, but also frank in the analysis of the causes of his eventual suicide (apparently the person most aware of the situation had been Dirac). During this time, he attended seminars delivered by Planck, Einstein and Pauli and other distinguished scientists.

Casimir's first postdoc was with Bohr (Ehrenfest introduced Casimir to Bohr saying 'He can do something, but he still needs a good thrashing'), and his account of Copenhagen refers to amusing places like the Cafe Antiautomat (set up as a protest against vending machines); to Bohr's preference for completing papers on Saturday (so the postal travel wasted only Sunday, not a workday); to watching Western movies with Bohr, Gamow and Landau (Bohr proposed a gunslinger effect positing that a willed movement is slower than an automatic reaction, implying that the person who is the later to draw in a gunfight is likely to win; Casimir provides a poem commemorating the theory). There is also an amusing Bohr story about identical twins (one of whom is sent to Harvard and the other to Yale) - but one has to read the book.

Casimir's second postdoc was with Pauli in Zurich, where he discovered upon arrival that church clocks in Switzerland were not quite synchronized. There are mentions of visits by Bhabha, of Pauli's friendship with Jung, and of Pauli's drunk driving. Later, in response to his stubbornness in argument, Pauli called Casimir a Stehaufmanderl, in reference to a toy which always returns to the vertical (because its center of gravity is so low).

Casimir was next recalled to Leiden by Ehrenfest so he could take charge of the theoretical physics division; he read about Ehrenfest's suicide while on the train from Copenhagen: the moves had likely been planned in advance. Leiden University made Casimir a professor at 30, but he did not believe himself to be a top notch theoretical physicist, and was relieved to be relieved (sic!) by the distinguished Kramers. I knew about Kramer's work in physics; the book reveals that he translated Mallarme, played the cello, and introduced Casimir to Tristram Shandy.

Casimir describes other giants of physics, such as Lorentz, whom he met only once. He gives a perceptive account of the scientist, who was remarkable in being both a 'classical' and a 'modern' physicist at the same time. This in the sense that he came from a pre-relativity and pre-quantum tradition of physicists, but remained in touch with developments so he did not become obsolete at any point in his career. Lorentz is often thought of as the main bridge between Maxwell on the one hand and Einstein and Bohr on the other.

Another person Casimir describes in some detail is Kammerlingh Onnes (KO), who discovered superconductivity at Leiden. Casimir regards KO as a pioneer, but criticizes his social prejudices (class conscious) as well as scientific administration (dictatorial).

There is a long chapter on WWII, describing the German occupation, after which Casimir chose to move to Philips. His stay in industry involved the development of many devices (radios, cyclotrons, etc.) and the interaction between fundamental science and technology, which he describes at length (he points out that scientists are often the first users of new technology, while technology takes some time to use the latest results in science). Overall, his insistence is on academic freedom for research, both in universities and in industry.

Some more interesting facts I learnt from the book:

1. After the war, Casimir was courted by universities abroad, including Rochester (which had recently lost Weisskopf).

2. In 1807, the University of Leiden had finally been able to expand when a barge carrying gunpowder and moored near campus accidentally (?) exploded and gutted about 500 houses.

3. Casimir was responsible for persuading B. G. Escher (M.C. Escher's half-brother) to teach crystallography at Leiden.

Summary:

An interesting read, covering the physics of the 1930s (there are two extensive appendices with Casimir's viewpoints on this era), from the pen of someone who was rather close to the central actors.