Saving Newton or destroying Newton? Popular and professional physics publishing in the 1920s

The below is based on a paper that I’m going to be giving at the 24th International Congress of History of Science, Technology and Medicine (iCHSTM). It’s an academic conference, but there are also public events and stuff (if you happen to be in Manchester at the end of July). And there’s a blog, where this post originally appeared.

History is a tricky business. For the majority of those who study it, our main source of information is words. These were written down long ago (or perhaps not so long ago, depending on your preferred time period) and were chosen by particular people for particular purposes. There are endless complications. Is it possible to tell if somebody was speaking from the bottom of their heart or deliberately manipulating their audience? How are we to uncover what happened before, during and after the act of communication? Just what are we supposed to do with all these words?

I suppose we could start by looking at some context. For my paper at ICHSTM, the context is early-twentieth-century British physics. This was a period of quite dramatic change in the discipline – the last few years of the nineteenth century had seen the discovery of X-rays, radioactivity and the electron (disclaimer: J. J. Thomson conceived of this not as the ‘electron’ but as a similar-but-different ‘corpuscle’). This was followed by the quantum and relativity theories, which really shook things up. The atom was broken up, matter was disintegrating, energy was jumping around in tiny packets, and time and space were sort of the same thing. The natural world was no longer as it had first seemed. It was all very exciting.

But when it came to talking about these changes, putting them into words, there were certain difficulties. Depending on how you interpreted the new ideas, there was the suggestion that they overturned a lot of previous knowledge, including Newton’s laws of mechanics. This didn’t sit that well with the idea of science as progressive, building on the work of those who had come before. Physics in particular was supposed to be sturdy, providing the foundations of all other sciences. But instead we had a discipline whose very foundations could seemingly be destroyed at any moment. Just as damaging, physics was apparently breaking ties with the father of modern science himself, Sir Isaac Newton. The implications for public trust in science were rather worrying, and physicists needed to take this into account when they spoke about their work.

In 1930, the physicist James Jeans published a best-selling popular science book, called The Universe Around Us. Here, describing how one can use the speed in orbit and distance from the sun of any planet in order to determine the sun’s gravitational pull, Jeans noted that this ‘provides striking confirmation of the truth of Newton’s law of gravitation’. And while Einstein had ‘recently shewn that the law is not absolutely exact’, this amount of inexactness was only revealed in Mercury’s orbit, ‘and even here it is so exceedingly small that we need not trouble about it for our present purpose’.  In the following few pages, Newton’s law was ‘confirmed’ twice more, and Jeans found himself again levying ‘toll on the mathematical work of Newton’.  When he moved away from celestial space on to notions of time, Jeans yet again found that ‘it is a matter of complete indifference for our present purpose whether we use the law [of gravity] in Newton’s or in Einstein’s form; for stellar problems the two are practically indistinguishable, and there is abundant evidence . . . in favour of either’.  For practical purposes, Jeans noted that he was happy to use either theory, or even any other ‘not entirely dissimilar law’.

But did Jeans really think Newton was still relevant, or was this a deliberate attempt to present physics in a certain way, at a time when it was in danger of losing its precious connections to the beloved 17th century scientist? How do we uncover the true meaning of his words? Perhaps by looking at another aspect of Jeans’ career, his position from 1919 to 1929 as Physical Secretary of the Royal Society. In this capacity, Jeans had a considerable amount of influence over what was published in the Proceedings of the Royal Society of London (Section A), one of the most prestigious physics journals in Britain. He decided whether papers should be immediately published, immediately rejected, or sent to a reviewer. And in this capacity, Jeans was no friend to older ideas and methods.

Responding to a paper that tackled atomic structure without incorporating recent ideas in quantum theory, Jeans declared that in such a problem classical mechanics led nowhere at all. This angered the communicator (although not author) of the paper, the Cambridge mathematician and self-styled curmudgeon Joseph Larmor. He confided in his friend Oliver Lodge, declaring that Jeans was now banning Newtonian atomic theory from the journal. While this was certainly an exaggeration, Jeans’ work at the Royal Society does indicate a hefty bias towards ‘modern’ physics. This is evident not just in his comments on papers, but also his choice of referees, with papers being passed on to ‘modern’ reviewers.

While Jeans was writing a popular publication that stressed the continuing importance of Newton, he was using a professional publication to dismiss ‘Newtonian’ contributions to the field. He was helping to establish a new status quo of modern physics, at the same time as obscuring the extent of this change from the wider public. The words he published, and allowed others to publish, were carefully chosen to create two contradictory consensuses (consensi?).

Of course, you might argue that quantum theory was fully accepted by the 1920s, so of course Jeans would choose quantum theorists as referees and reject papers that attempted to bypass now-established theories and practices. And perhaps his popular book was simply a valiant effort to hide certain anti-Newtonian developments from a naïve public that frankly didn’t need to know this stuff. This is one interpretation. An alternative is that we now think quantum theory was accepted by the 1920s because of the very editorial policies employed by Jeans. We might also suggest that Jeans wasn’t helping a confused public, but rather manipulating them to protect his, and his discipline’s, own interests. Words can be powerful tools.

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