I have been meaning to post this review for quite some time and just haven’t gotten around to it until now. That should in no way reflect how I felt about the book (as you will see if you continue to read this post).
Author: Meg Weston Smith (Foreword by Roger Penrose)
Publisher: Imperial College Press, 2013
Let me begin by saying that I am very privileged to actually know Meg Weston Smith personally. I am forever indebted to her for her kindness and hospitality in welcoming my wife, my then-eighteen-month-old son (now 13 years old!), and me into her home many years ago when I was doing research for my PhD. Over the years she provided numerous bits of information on Milne and his relationship to Eddington that proved to be immensely helpful (not to mention fascinating). E.A. Milne was her father and I know just how long she has been working on this project which was started as a way to learn more about him (he died at the age of 54 when Meg was just 17).
At points poignant and at points heart-breaking, but wholly inspirational, the story of Edward Arthur Milne is one of striking success in the face of seemingly insurmountable odds. Twice widowed before the age of 50 (both times to suicide) and hampered by progressive Parkinsonism as a result of contracting encephalitis lethargica during the outbreak that swept around the world in the early 1920s, he persevered and became one of the giants of 20th century astrophysics, cosmology, and mathematics. While known primarily for his work in astrophysics, he made seminal contributions to ballistics during both World Wars, during the second of which his house was destroyed by a German V-1 launched in retaliation for the D-Day invasions. I suppose there is some dark irony in that fact.
Also less-well-known is the fact that Milne was the first to suggest that light signals be used to standardize time measurements. This, of course, is exactly how the SI unit of time – the second – is presently defined. The present definition is not quite what Milne had envisioned. In fact the present definition of the meter is actually closer to his original idea. Nevertheless, special relativity implies that the second could easily be defined in similar terms. Tom Moore has an excellent derivation of the Minkowski metric using light clocks in his book Six Ideas That Shaped Physics, Unit R: The Laws of Physics are Frame-independent. Milne originally received a great deal of criticism for this idea. Max Born referred to Milne’s light signals (used to measure time) as “weird inventions.” Of course, Milne got the last laugh.
Part of Milne’s problem was that he held some unconventional views that were unfortunately seized upon by Herbert Dingle who never missed an opportunity to publicly ridicule them. It may seem strange in retrospect that Dingle, who strongly opposed special relativity because it was grounded in theory and not experiment (though has nevertheless been repeatedly experimentally verified), should actually be taken seriously, but one must realize that these were very early days in modern physics, before the cosmic microwave background radiation was discovered, before dark matter and dark energy, before string theory and loop quantum gravity. Like Eddington, with whom Milne had a close friendship but strong professional disagreement, it may be that Milne was ahead of his time. Some of Milne’s ideas are enjoying a bit of a renaissance, though in somewhat altered form. In my own work on CPT-symmetry I have begun to wonder if there might actually be more than one sense of time, as Milne had suggested.
It should be said that Milne was, first and foremost, a mathematician and was thus very strongly grounded in theory as driven by mathematics. This also squarely put him in the camp of what I like to call the “deductivists” whose standard-bearer at that time was Eddington. The deductivists put a priority on theoretical and mathematical derivations. Einstein himself was essentially a deductivist in that he famously said, in response to a question posed to him when Eddington’s results turned out to match his theory, that any experiment that disagreed with relativity would simply be wrong. Today, Milne, Eddington, and Einstein would not actually be considered all that radical. Max Tegmark, for instance, firmly believes that the universe is entirely mathematical. I would think that Milne would find something of a kindred spirit in Max.
At any rate, all of these thoughts were prompted by my (relatively) recent reading of Meg’s wonderful book. I highly recommend it to anyone with an interest in the history of science or even just in history itself. It is not technical and so does not require any mathematics background to read. The book itself is deeply personal and yet wholly accessible. It is a terrific homage to a father who sincerely tried his best to provide for his family and to serve his country, college (Wadham), and students, all while contributing a wealth of ground-breaking and enduring ideas to applied mathematics.