Kelvin and Michelson and Historical Myths
On famous misquotations...
It was a bit of an “information supercollider” morning here, with a couple of things crossing paths in my feeds in a way that led more or less directly to this post. One of those is this 1975 article from the University of Chicago magazine reminiscing about watching Albert Michelson play billiards, posted in response to a silly joke I made. It’s a lovely piece, which probably isn’t a surprise given the author:
When I came to the University as a Graduate Assistant, then, I was just as good a billiards player as I had had spare twenty-five cent pieces when I was in high school, and, still aspiring to be better, I ate my lunch early to get downstairs and watch the club champion.
Michelson was the best billiards player I have ever seen at the University, and I think I have seen all the really good ones, including the barbers at the Reynolds Club. At first I was somewhat embarrassed to see how good he was, because I did not expect to find any academic type as good at a “manly sport” as the best we had in western Montana. But the more I thought about it and the more I learned about Michelson, the less surprised I became. Before long, I comforted myself with the question, “Why not? He’s the best head-and-hands man in the world.”
So it wasn’t just billiards I watched when I arrived early every noon to watch Michelson play billiards. I came to watch his hands. The year 1928 was still in an age which counted men who made machines among its marvels and took for granted that the rest of men could use tools and that women could embroider beautifully. Edison still performed his wonders, but the wonders of Bell and Edison were more or less household utilities. Michelson’s head-and-hands made machines almost godlike in properties, designed to tell us how it was with the universe. His favorite creation was his interferometer, with which, among other things, he (and later a collaborator, Edward Morley) had performed an experiment that shook the old universe and gave Einstein a big push toward creating a new one with his theory of relativity.
The other piece is also a bit of silliness, this time from Sabine Hossenfelder, who posted a Bingo card mocking the tropes of the recurring arguments in favor of building a bigger-than-the-LHC particle accelerator:
This isn’t really an argument I care to rehash, but the “Lord Kelvin was wrong!” at the lower left caught my eye, because he’s pretty closely linked with Michelson in my mind, thanks to a tendency to misquote the both of them.
Kelvin (born William Thomson before he was knighted for his work on the trans-Atlantic cable then made Baron Kelvin for his work on thermodynamics and oppressing the Irish) is the go-to whenever somebody wants to cite a British scientist of the late 19th century, and often serves as a symbol of the arrogance of physicists in the pre-”modern physics” era. (“Modern physics” here being a term of art within the profession, meaning “Relativity and quantum physics up to around 1950.”) He’s regularly misquoted as triumphally announcing that physics was essentially complete, though in fact he didn’t say anything of the sort.
Michelson comes in here because he is slightly more accurately quoted as saying something along those lines, namely that “our future discoveries must be looked for in the sixth place of decimals,” which is a sentence that appears in an actual lecture that he gave in the early 1900s. He actually attributes that sentiment to others, but it’s closer to an accurate quote than much of what people put in Kelvin’s mouth.
When I first verified the wording of the Michelson quote, I was a bit dismayed, because I really admire him and his work and didn’t want him to be wrong in that way. On looking it up, though, I found that he’s actually not using that line in the way that it’s usually quoted; instead it’s part of a pitch that is very much aware of the likelihood of finding new physics.
This is a thing that I wrote about in A Brief History of Timekeeping (buy my book!), and because I did that and I have other things to do today, I’m going to indulge in a lengthy self-quotation (from a late draft of Chapter 12, which I have in an electronic format that is more easily pasted in here than I have for the final published text):
In many popular tellings, physics in the late 1800s was in a state of arrogant complacency: between Newton’s Laws and Maxwell’s Equations, plus the rapidly developing science of thermodynamics and energy, physicists thought they had everything figured out. To illustrate this attitude, many authors cite quotes of the form “There is nothing new to be discovered in physics; all that remains is more and more precise measurement,” often attributing them to the eminent British physicist Lord Kelvin in 1900.
There is, however, no direct evidence that Lord Kelvin ever said any such thing. The closest solid citation is a lecture by Albert Michelson, published in 1902, where he wrote “The more important fundamental laws and facts of physical science have all been discovered, and these are so firmly established that the possibility of their ever being supplanted in consequence of new discoveries is exceedingly remote,” and later attributed to unnamed others the sentiment that “our future discoveries must be looked for in the sixth place of decimals.”
The fuller context of Michelson’s lecture, however, makes clear that this was not a dismissive statement of arrogance, but an affirmative statement regarding the importance of high-precision measurement. The material between those two quotes includes an explicit statement that “it has been found that there are apparent exceptions to most of these laws, and this is particularly true when the observations are pushed to a limit, i. e., whenever the circumstances of experiment are such that extreme cases can be examined,” followed by a partial listing of great discoveries made by observing small anomalies at extremes of precision.
Michelson’s invocation of “the sixth place of decimals” was actually part of a pitch for building up the capability to do measurements at that level. This should come as no surprise, because such measurements are the source of his own scientific fame: he was renowned as an exceedingly careful experimentalist, who had made one of the best measurements of the speed of light in 1879. And as we’ll see in this chapter, another of his experiments at the very limits of measurement precision played a pivotal role in launching a revolutionary re-examining of the nature of space and time.
As for Lord Kelvin, who is regularly mis-cited as believing that physics was essentially complete, when given the opportunity to present a sweeping overview of the state of physics in 1900, the result was a lecture titled “Nineteenth century clouds over the dynamical theory of heat and light.” In this he identifies two major issues that he worries are obscuring “the beauty and clearness of the dynamical theory, which asserts heat and light to be modes of motion.” One of these is the connection between heat energy and the light emitted by atoms, which was one of the problems that led to the development of quantum mechanics (which we’ll talk more about in Chapter 13). The other had to do with the nature and transmission of light, and as we’ll see in this chapter, this eventually led to what we now call the theory of relativity.
Lord Kelvin and the other leading physicists of his day were not, as some tellings have it, complacently arrogant about physics having the world completely worked out. On the contrary, they were keenly aware of the problems facing their field, which would lead to the creation of two theories that would radically re-shape our understanding of the universe and how it operates. And each of these revolutions, in its own way, is rooted in an intensely practical question of timekeeping: how to keep clocks in distant places showing the same time. Answering that question turns out to have profound consequences for our understanding of time.
If you want more details about Kelvin’s lecture, this history article seems pretty good (on a quick read).
This is an example of a phenomenon that’s distressingly common in pop-science writing (and also punditry more generally), including by people who really ought to know better: the tendency to do a kind of superficial version of due diligence, poking around in history just enough to find something that seems faintly plausible as representing a point of view they want to set up, but not far enough to check that what it actually says is the same as what they say it says.
It’s a hard problem to avoid, of course, and I’m sure I’ve fallen into it myself. I’ve repeated a colorful quote attributed to Heinrich Hertz a bunch of times in lectures and quoted it in at least one book, only to find that there really isn’t a solid source for it. The specific and very vivid phrasing (“It's of no use whatsoever ... this is just an experiment that proves Maestro Maxwell was right—we just have these mysterious electromagnetic waves that we cannot see with the naked eye. But they are there.”) just sort of… shows up in a sidebar in a textbook at some point, and all the subsequent citations eventually trace back to there. It took hours of poking around to convince myself that there wasn’t a solid source for it, which is a deep rabbit hole to fall into for a good line that’s just being used to add a bit of color.
But it’s good too be reminded occasionally of the importance of actually doing the work, and checking not only that the people you’re quoting said the thing you’re quoting them as saying, but also that what they meant by it is the same as what you’re interpreting it to mean.
That’s a little self-indulgent, but what the hell. If you want more in this vein, well, buy my book, but also you can click this button:
And if you know an actual source for that Hertz line (hope springs eternal!), the comments will be open:
Chad, great post (again). Alas I have no source for the Hertz quote (probably somewhere out there in a memoir in the original German). Many of these famous quotes come from Pais, so I might look there. Michelson is (obvs) close to my heart. Interestingly there has been no serious biography of him since his daughter's retrospective (Master of Light, 1973...an awesome title too!). It seems like it would be a real winner: emigree from Silesia, lived in the Gold Rush old West, personally got U.S. Grant to give him a appointment to the Naval Academy, life at sea, etc. He was recalled to active duty twice: once during the Spanish American War and then again in WWI (!), he was in his mid-40s. The Navy in all its wisdom stashed him in some dead end administrative job during WWI...he hated it! The myths about him at Navy abound: he apparently was a real martinet when he was a passed Lieutenant on staff. He essentially impressed young Midshipmen into service to stoke the boiler he used to run his rotating mirrors when he did the speed of light experiment...the process he used to calibrate the rotational rate (tuning forks and image recovery) is pretty amazing. If you get a chance to come to Annapolis, let me know, we have many of his historical instruments displayed in the basement and the museum has his Nobel medal.
Ironically, a good chunk of physics has been stalled out in a similar way since the confirmation of the Higgs boson and the Standard Model. Now, the big hope for new physics is in finding anomalies in the moment of a muon or deviations in galactic rotation. Meanwhile, there's a feeling that physics can explain every familiar phenomenon needed for daily life and daily technology. There's nothing wrong with this save for a disquieting sense of stasis after an era of transformation. There's also an unsettling feeling that we are staring at new physics in the face and not realizing that we are seeing it.