Scientists and the symmetry principle: an email exchange with Steven Weinberg

Earlier this week I received an email from Steven Weinberg, the physicist whose book To Explain the World was critically reviewed by Steven Shapin earlier this year. I commented on Shapin’s review in this essay, and in the process I attributed errors to Weinberg that he disclaimed in his email. Weinberg asked that I publish his email, and my reply, on this blog. I was happy to oblige. As I point out in my reply, Weinberg’s reaction to my essay is an additional reason to adopt the symmetry principle that I defended in earlier posts.

Here are the relevant parts of Weinberg’s email:

Dear Dr. Bycroft,

I found a good deal with which to agree in your February 24 blog essay ‘Why historians shouldn’t write off scientists: On Steven Shapin’s review of Steven Weinberg’s [To] Explain the World,’ which I have just seen. But I was infuriated by your reference to ‘the real error in Weinberg’s book,’ that I have ‘judged past scientists by first establishing whether their theories were true or false, and then by assuming that the true ones must be the result of sound reasoning and the false ones the result of incompetence.’

No one who had read my book with an open mind could possibly reach such a conclusion. Throughout my book I was concerned much less with whether scientific theories were right or wrong, than with whether their proponents were advancing the methodology of science. For instance, as noted by a reviewer in the latest issue of The New York Review of Books, I emphasized that the good guess of Democritus—that matter consists of atoms—did not show that his reasoning was sound, and that in fact he had offered no reasoning to support this guess. Like all the pre-Socratics, his theory had no bite—it led to nothing that could allow it to be confirmed. Also, I explained that, although Ptolemy was wrong about the solar system, he had made an important methodological contribution in adjusting the parameters of his theory to get quantitative agreement with observation. I was careful to point out the errors of Galileo about comets and of Newton about diffraction.

Later in your essay, you refer to other supposed ‘errors’ of mine. In short, of these too I am innocent.

To your credit, you were honest enough to admit that when you wrote this you had not read the book, and were relying on Steven Shapin’s description. The dangers of such a procedure are evident.

Here is my reply:

Dear Dr. Weinberg,

Thank you for taking the trouble of reading my blog essay on Steven Shapin's review of your book. I am glad that you found ‘a good deal with which to agree’ in the essay. I hope it was clear from the essay that my main target was Shapin’s review, not your book. If had intended to write a review of your book, I certainly would have read the book before casting aspersions on its content, as I do on two occasions in my essay.

On one occasion (‘As Shapin points out, it ignores...’) my phrasing is ambiguous. I seem to say that I have information about your book that is independent of Shapin's review. This is not the case, and I have inserted a footnote to this effect.

On the other occasion I say that I am making an educated guess based solely on Shapin’s review. Perhaps I should have added that this was a risky guess based on a small sample of citations plucked from the review. In any case, I have spelled this out in the footnote I just mentioned.

In making this educated guess I was less interested in evaluating your book than I was in drawing attention to what is known in the trade as the ‘symmetry principle’ or ‘methodological relativism.’ As I have argued elsewhere on my blog, this principle is badly misunderstood. Even professional historians of science have trouble saying what it is and why we should adhere to it. There is a tendency to confuse the principle with the idea that historians should never evaluate past science, or that they should never invoke the truth of a belief to explain that belief, or even that intellectual factors matter little in scientific debates. The result is that many legitimate and useful practices are criticised on the grounds that they violate a principle that few historians are able to articulate in a coherent manner. My remarks on your book were part of my effort to separate the many putative symmetry principles from the real one.

What is the real symmetry principle? I gave my version in the post in question. It is that we should not ‘judge past scientists by first establishing whether their theories were true or false, and then by assuming that the true ones must be the result of sound reasoning and the false ones the result of incompetence [or worse].’

You imply in your email that you agree with this principle. I find this very heartening. In the past, historians and sociologists have had great trouble persuading scientists that there is a version of the ‘symmetry principle’ that is worth taking seriously. The One Culture?, which I reviewed recently on my blog, and which featured chapters by yourself and Shapin, contains ample evidence of this problem. It looks like we have found a solution.

The symmetry principle would be worthless if no-one was ever tempted to violate it. I am grateful for the examples you invoke to show that you have not done so. I think the Galileo and Newton examples are equivocal. They would only be telling if you specified the causes of the errors in question. Did these men go wrong because they were temporarily disabled by a bad method or a social or psychological bias, or because even the best methods and the most clear-eyed scientists will go wrong some of the time? Both explanations are consistent with the symmetry principle, as I understand it. But the former is also consistent with a violation of the principle.

The Democritus and Ptolemy examples are more convincing. There are comments under my blog essay that defend your book along similar lines, eg. the comments by Michael Weiss (here and here) and by Will Thomas (here). As you point out, however, it is better to read a book than to take someone's word on its contents. So I will reserve judgement on your methodology until I have had a good look at To Explain the World.

I hope that the two offending passages in my essay do not obscure my broader point, which is that the methodological gap between professional historians (like Shapin) and scientist-historians (like yourself) is smaller than the former group sometimes makes out. The symmetry principle is one aspect of this. Another aspect is the fact that scientist-historians have actually done the thing (science) whose history they study. You may be interested in a more recent essay in which I look into this issue, starting with your statement that history is something that you ‘visit as a tourist.’

Weinberg wrapped things up with the following:

Dear Dr. Bycroft,

I’m heartened by the convergence in our views. In particular, I do agree with the ‘symmetry principle’ as you have stated it, though this is one symmetry principle that had previously escaped my attention. I agree that the comments in my note to you about Newton’s fudging and Galileo’s error are not relevant to this principle. I included these comments only to exonerate myself from accusations of hero worship. As you say, the relevant examples cited in my note were those having to do with Democritus and Ptolemy.

Expand post.

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Is it post-modern to be present-centred? Thoughts prompted by Nick Tosh

Lorraine Daston says that historians who write with the present in mind are misguided and old-fashioned. By contrast, Nick Tosh says they are post-modern. He compares them to contemporary novelists who draw attention to themselves, and to the process of writing novels, in the course of their novels. Against Daston, I said that it is not what you know about present-day science that matters, but how you use that knowledge. Against Tosh, I say that present-centredness is not post-modern because it does not leap from the fictional world to the real world but only from the present and the past. And very often it does not even do that.

Don’t get me wrong about Tosh. His discussion of history of science as literature is sharp and original. It appears at the end of his article ‘Science, Truth and History, Part I: Historiography, Relativism and the Sociology of Scientific Knowledge,’ Studies In History and Philosophy of Science Part A 37:4 (2006): 675-701 (paywall). He starts by distinguishing two kinds of reader:

A work of history is written for members of one language game about members of another. To read such a work is not literally to jump to an alien language game, of course, any more than to ‘feel another’s pain’ is to jump to an alien consciousness, but good history writing can sometimes induce illusions along those lines. It is obviously crucial that the reader bear in mind the artificiality of such experiences. Genuine historical understanding requires more than a passive talent for empathy: it requires an active appreciation of the logical gap separating us from a past culture, and of the historian’s role with respect to that gap.

We can draw an analogy with fiction here. A naïve novel reader is simply someone who can lose himself, on demand, in a make-believe world spun by the novelist. A sophisticated reader (also) understands something about the process of creative writing (as an activity in the real world), and about the kinds of interactions that take place between author, characters and reader. The aesthetics of fiction are not just about pleasing the first sort of reader.

That should be clear enough. Tosh goes on to say that post-modern novels target the sophisticated reader:

‘Post-modern’ novels can be seen as emphasising their own artificiality. Consider, for example, this authorial intrusion one-quarter of the way through Martin Amis’s Money:

I was just sitting there, not stirring, not even breathing, like the pub’s pet reptile, when who should sit down opposite me but that guy Martin Amis, the writer. He had a glass of wine, and a cigarette—also a book, a paperback. It looked quite serious. So did he, in a way.

What Goffman called ‘breaking frame’ and the Russian formalists ‘exposing the device’ is not supposed to cheapen the reader’s appreciation of a particular novel; it is supposed to deepen his understanding of fiction in general. If one can’t escape the contrived nature of the novel-reading experience, then, as an author, one might as well stop trying to and instead make artistic points about (and through) it.

Next Tosh returns to the history of science, pointing out a striking inconsistency between theories of history and literature:

So we can distinguish two basic authorial responses to the gap between fantasy and reality: pretend, for aesthetic reasons, that it doesn’t exist, or stress, for different aesthetic reasons, that it does. Traditional novelistic etiquette emphasises the former tactic; post-modern novelists have often plumped for the latter. It is perhaps rather odd, then, that while an analogous pair of conventions exists for history writing, the cultural connotations are almost exactly reversed [my italics, not Tosh's]. ‘Breaking frame’ is such old news in the history business that it hasn’t even got a flash name. It is the absence of authorial intrusion (that is, the absence of modern moral or epistemic judgements) that is likely to get a work of history labelled ‘post-modern’ or ‘relativist’. While their philosophically-inclined colleagues theorise endlessly about cultural separation and the historical ‘Other’, post-modern historians of science do their best to keep the present out of their narratives—to make separation and otherness invisible. Actors’ categories history, like the traditional novel, is a genre that seeks to hide its own artificiality; it seeks to cooperate with the reader’s attempt to suspend disbelief...

Tosh ends with a remarkable prediction:

I will end this coda by hazarding a prediction, inspired by the history of the novel but grounded upon the above argument. The aesthetic bias that lies behind cultural history’s methodology (and, arguably, SSK’s philosophy) may not in fact be a very long-lived one. Future historians may read our cultural histories, including our histories of science, rather as we read the great classics of Victorian fiction: marvellous achievements in their own way, but ultimately limited by the strict literary form to which they adhered.

***

Tosh may be right that cultural histories, with their lush reconstructions of past beliefs, will soon be replaced by a more knowing kind of history. But if the replacement is truly post-modern, it will not be present-centred history as we know it.

One reason is that historians write about the world we all live in whereas novelists write about a different, imaginary world. This means that the ‘authorial intrusions’ of the historian as less jarring than those of the novelist. When Martin Amis put himself in his novel, he stepped from the real world to the fictional world. When Mary Boas-Hall criticised Thomas Hobbes, she stepped from the twentieth century into the seventeenth. The former jump is (we might say) metaphysical, whereas the latter is merely chronological.

Only the former jump has an air of paradox that invites the label ‘post-modern.’ Fiction does not work unless the reader believes, at some level, that the events being described really happened. The effect of the ‘authorial intrusions’ that Tosh associates with post-modern novels is to remind the reader that the events didn’t actually happen. There is no equivalent paradox for history. It is true that history only works if the reader believes that the events being described happened in the past. It is also true that, when the historian refers to himself in the course of a book, he reminds the reader that the book was written in the present. But there is no paradox here. The reader is not asked to believe that certain events both did and did not happen. He is asked only to believe that historians can find out about the past.

My other objection to Tosh is that, despite its name, present-centred history does not necessarily involve chronological jumps. Suppose a historian writes: ‘the mercury in Hobbes’ barometer was held in place by the pressure of atmospheric air, not by nature’s aversion to vacuums.’ The event being described here, the motion of the mercury, is an event in the seventeenth century, not in the twentieth. The statement does not require a chronological leap any more than the statement ‘Boyle was a devout Christian’ requires such a leap. Granted, we can easily introduce a chronological leap, for example by prefacing the sentence with ‘As we now know,’ or ‘In my opinion.’ But the critics of present-centred history of science do not make such nice distinctions—they would criticise the statement even without the prefatory phrase, calling it anachronistic.

The statement does make a leap, but it is one of narrative perspective rather than chronology. A historian who makes that statement has departed from Hobbes’ perspective, since the statement contains an explanation that Hobbes rejected. Which perspective has the historian adopted, if not Hobbes’? We could say that he has adopted Boyle’s perspective. But that would raise the question of why he has favoured Boyle over Hobbes. Worse, in many cases there will not be a Boyle waiting in the wings to serve as spokesperson for present-day theories. It looks like we are forced to say that the historian as adopted his own perspective, which suggests that he really has made a chronological leap.

But there is another option. We can borrow a phrase from literary criticism and say that the historian has adopted the perspective of the omniscient narrator, the voice that speaks for no-one but is aware of everything. In fiction, the omniscient narrator often describes events that none of the characters in the story will ever be aware of. To pick a random but vivid example, there is a passage in Steinbeck’s The Grapes of Wrath that describes the gradual decay of a house abandoned by share-croppers. The whole process is witnessed only by pigeons and stray cats. Yet there does not seem to be anything jarring or post-modern about this passage. It is completely different from the Amis passage that Tosh quotes. The ‘authorical intrusions’ of present-centred history are more like the Steinbeck passage than the Amis one.

If the statement about Hobbes’ barometer is not post-modern, what would count as post-modern history of science? Well, what makes the passage from Amis post-modern? Tosh highlights the following two features. Firstly, Amis refers not just to himself but also to process of writing novels. Secondly, this reference draws attention to the ‘artificiality’ and ‘contrived nature’ of novels. So we are looking for histories of science that refer to the process by which the histories were researched and written (not just to the beliefs of the author). We are also looking for histories that draw attention to the weakness or partiality of our knowledge of past science (which is not the same as drawing attention to differences between past and present science). Perhaps there are histories that meet both of these criteria, but I do not know of any. What I do know is that histories of this kind would be quite different from the present-centred histories of Whewell or Sarton or Weinberg. Expand post.

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Lorraine Daston on history as fiction – critical thoughts

Nick Tosh and Lorraine Daston have, separately, made some intriguing remarks about the affinities between fiction and the history of science. Their remarks follow on nicely from my last post. Daston compares historians to readers of mystery novels who know in advance how the story ends. She means this as a criticism. By contrast, Tosh praises authors who freely acknowledge the gap between themselves and their subjects, a stance that Tosh labels ‘postmodern.’ My position is somewhere in between: it is OK for readers to know how the story ends, but this is not a particularly postmodern phenomenon.

Daston made her remarks in a 2012 interview with the Canadian radio station CBC:

Imagine you’re the kind of person who cheats when you read mystery novels, and you read the last page first, to find out who did it. And then when you read the rest of the mystery story, you know that everything is building towards this climax. You read it in a very different way than the person who has to retrace all of the red herrings that have been planted in your way by the author, to throw you off the scent of the real villain. We the historians of science were always the people who read the last page first, and we knew how the story ended.

This statement is plausible on the surface: you read a novel differently if you know the outcome, and historians of science usually know the outcome of the scientific debates they study. But note that Daston has compared two different ways of reading a detective novel, and that she uses this comparison to assess two ways of writing history. Foreknowledge may change the way we read, but does it change the way we write?

The analogy to detective fiction suggests that it does not. Mystery writers do know the outcome of their stories, and despite this they revel in the kind of red herring to which Daston refers. And why not say the same about readers? If the prescient writer can appreciate the red herrings, why not the prescient reader? As per my last post, mystery novels can be gripping even when we know in advance who committed the crime and why.

Daston continues:

Moreover, we were complicit in this with the scientists themselves, who wish to have a story about why we believe what we believe now, and why it is right, because the scientist knew, in a way that the historian did not know so viscerally, that everything—or most things—that we now believe in science will be overturned, if not in a generation then in two generations. This is the progress of science, but it is the pathos as well. Therefore the reassurance of that kind of history of science was: it is inevitable to believe what we believe now, indeed there are no other possible positions one could have...it was that deep reassurance which more than we the historians needed, the scientists needed.

In other words, by writing history with the outcome in mind, historians made those outcomes seem more rational than they really were. This reassured scientists because deep down they knew that most of the outcomes were not particularly rational. My objection is the same as the one I stated above. Historians and their readers can include all the red herrings—all the accidental developments, the roads that led nowhere, and the roads that might have led somewhere but were not taken at the time, and might still be taken—they can include all of this even though they are perfectly aware of what scientists now believe.

What I find especially odd is the idea that knowledge of the status quo is a conservative force, one that stifles dissent and disagreement. In the political realm, those who seek change are usually well advised to study the way things are. This knowledge can be rhetorically as well as strategically valuable. It allows the revolutionary to present his cause as a lonely struggle against massive opposition—not so much opposition that the cause is hopeless, but enough to endow it with romance and urgency. Animal rights activists do not ignore the mistreatment of animals. On the contrary, they spell it out in gory detail. Feminists do not turn a blind eye to laddish behaviour—they hunt it down and string it up. Many skeptics about climate change do not deny that there is a scientific consensus on the topic—instead they try to show that the consensus is rotten.

The grain of truth in Daston’s statements is that historians who overemphasise the present condition of science are usually the ones who exaggerate the naturalness of that condition. My point is that the source of this exaggeration is not knowledge of present-day science but the way this knowledge is used. The principal error is to assume that the theories of present-day science were as defensible in the past as they are today—that there was as much evidence for them in the past as there is today. In history and in mystery novels, it does not matter whether we know how the story ends. The important thing is to not mistake the story for the ending.

Nick Tosh follows in my next post. Expand post.

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Histories of science as murder mysteries, or: Steven Weinberg as Henning Mankell

The conclusion of my last post was that scientists who write history are like visitors to one city who live in a different city (as opposed to historians, who study cities while living in the countryside). The point of the analogy was to show that knowledge of present-day science need not get in the way of good history-writing. There is another analogy that gets at the same point from a different direction: scientists who write history are like authors of murder mysteries who reveal the identity of the killer in the first chapter. This may sound like a criticism, but there are successful authors who actually write like this, starting with the Swedish maestro Henning Mankell.

SPOILER ALERT - crucial details of detective novel revealed below, most of them from the first chapter

Consider Mankell's Villospår (1995), also known under the much less chilling title Sidetracked. Four of the murders in the story are narrated from the point of the killer, which means that the reader is always several steps ahead of the detective, the stern but sensitive Kurt Wallander. Within the first 20 pages we know that the killer acts alone, rides a small motorcycle, attacks his victims with knives and axes, is engaged in a vendetta on behalf of his sister, and buries the scalps of each his victims under the window of the hospital ward in which his sister is confined.

Wallander knows none of this. If he knew all of it, he would solve the mystery after the third murder, if not before. This would make the book shorter and much less interesting. It would mean that, as readers, we would not find ourselves in the edifying position of admiring Wallander’s deductions while knowing that his conclusions are wrong. We would not take nearly as much pleasure in the suspenseful meetings between Wallander and the person who (as we but not Wallander knows) committed the grisly murders. Nor would we know that Wallander placed his life in danger by speaking to this person. Most of all, our attention would not be drawn away from the facts of the murders (these facts are boring because Mankell hands them to us on a plate) and towards the process by which Wallander discovers those facts. This process, including the many dead-ends along the way, is the real mystery of the novel.

Mankell’s approach in Sidetracked is not unlike Steven Weinberg’s in To Explain the World.* Weinberg makes no secret of the fact that the earth follows an elliptical path around the sun, that inertial motion is rectilinear rather than circular, that the speed of light is finite, and numerous other present-day orthodoxies that were out of reach of many of the past scientists he discusses.

These disclosures do not ruin Weinberg’s narrative any more than they ruin Mankell’s. On the contrary. They teach us that skilled scientists can be wrong for the right reasons. They lead to dramatic scenes in which scientists come tantalisingly close to a discovery without quite getting there, where they unwittingly endanger their lives or careers by meddling with phenomena they do not understand, and where they become acquainted with a new entity without correctly identifying the entity (for an example of the latter, consider Joseph Priestly’s isolation of oxygen). Most importantly, a plain statement of the facts of nature has the paradoxical effect of drawing our attention away from those facts and towards the circuitous route that leads eventually to their discovery. This route, not the facts themselves, is the real story of the history of science.

Granted, there are relevant disanalogies between histories of science and murder mysteries. One is to do with the contemporaneity of those who know the facts and those who inquire about them. In Sidetracked, as in most murder mysteries, the facts about the crime are known (by the criminal) even before the inquirer (the detective) knows that a crime has been commited. In most histories of science, the facts about nature are not known by anyone until they are discovered by one of the principal inquirers in the narrative.

The second and related disanalogy is that, in a murder mystery, the discovery of the facts is almost always part of the story—the murderer, the means and the motive are correctly identified by someone in the book, usually near the end. By contrast, histories of science need not end with the identification of a true theory or the correct identification of a phenomenon. Often they do, but there is nothing in the rules of the genre that requires this.

These disanalogies do not seriously undermine the point I am trying to make, which is that histories of science can benefit from knowledge that is unavailable to most or all of the scientists they deal with in any given narrative. The first disanalogy is harmless because in both cases—histories of science and murder mysteries—the reader has access to facts that are unavailable to the inquirer. It does not matter whether there is someone else, living at the same time as the inquirer, who knows those facts as well as the reader. The second disanalogy is harmless because there are enough histories of science that do end with a correct solution to a problem to make the comparison to murder mysteries worthwhile.

I am not the first to compare histories of science to murder mysteries. Lorraine Daston has also done so, though not in the same way as I have just done. And Nick Tosh has some interesting remarks on the literary merits of historians who, like Weinberg, wear their present-day knowledge on their sleeves. I respond to Daston and Tosh in my next post.



*As I imagine Weinberg’s book, which I have still not read. It matters little whether my hypothetical description of Weinberg’s book is accurate. The features I describe are endemic in the kind of histories of science that are called ‘Whiggish’ or ‘present-centred.’ Expand post.

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Are scientists who do history like tourists? Thoughts on Steven Weinberg's analogy

A couple of months ago Will Thomas posted his thoughts on the Shapin-Weinberg episode. You may have read Steven Shapin's unflinching review of Steven Weinberg's new book To Explain the World. The theme of the review, and of the replies and reflections that followed, including my own, was the quality of history written by scientists. One view that Will outlines is that scientists' history serves only to propagate self-serving myths about science. Will's own view is that this is itself a myth, and that historians should treat scientists as tourists whose well-meaning forays into past science are a net gain for the discipline. I like the tourist analogy, but I think it can be modified to better explain that net gain.

The source of the analogy is Weinberg. ‘I work and live in the country of physics,’ he said, ‘but history is the place that I love to visit as a tourist.’ A fine sentiment, but Weinberg is selling himself short. As the name suggests, history of science is about science. It follows that scientists have a relationship with the history of science that non-scientists do not have: they do the thing whose past is being described. True, they do not do exactly the thing that is being described, because that thing has changed over time. But they are doing something similar.

I want to put the stress on the doing. There is a case to be made that scientists have special knowledge of past science by virtue of the fact that they do science in the present. Moreover, this is a kind of knowledge that most historians of science do not have, since most of us are not practising scientists.

The case is easier to make if we suppose, as many historians of science do suppose, that much scientific knowledge is tacit in the sense that it is difficult to write down or has not yet been written down. This supposition has driven historians to replicate past experiments and to collaborate with present-day artisans in order to get behind the veil of words and understand scientific practise. Hasok Chang and Otto Sibum are examples of historians who replicate. Pamela Smith, and her Making and Knowing Project at Columbia University, is an example of collaboration with artisans or ‘expert makers.’

Collaborating with a silversmith is one thing, you might say; working with a physicist on a history of physics is another thing. But what’s the difference? Are we to believe that there is more tacit knowledge in the silversmith’s workshop than there is in the physicist's laboratory? Surely not. At least, most historians of science who are skeptical about the historical abilities of scientists would deny that there is any such difference. I expect Shapin would, for instance.

If scientists do have special knowledge of past science, then the relationship between scientists and historians of science is more complex than one straying into the domain of the other. It is not a case of scientists paying a casual visit to a city that they know nothing about and in which historians have always lived. We need to tweak the analogy. My version is messier than the original but, I hope, more accurate:

The historian is like a person who lives on a farm in Iowa and spends most of his professional life reading about London using whatever material he can find—internet, radio, newspapers, tourist guides, the lot. In this way he has acquired a wealth of information about London and about literature on London, but he has never lived in London or in any other city.

The scientist is like a person who lives in Washington, D.C. London intrigues him because it, too, is a city. So he reads up on London in his spare time. He will never read as much about London as the Iowan, who is a dedicated professional. But he has the advantage that he has lived somewhere that is, like London, a city.

In this analogy, city life corresponds to life in the sciences, and farms to life in the humanities. The US corresponds to the present, and the UK to the past. There is a big gap between the two nations, enough to baffle the tourist, but stretched across the abyss there is a rich web of resemblances. The fact that neither the Iowan nor the Washingtonian actually goes to London corresponds to the fact that neither the historian nor the scientist goes back in time and does past science. They both rely on texts and objects that survive from the past, just as the Washingtonian and the Iowan rely on pieces of London that make their way across the Atlantic.

The lesson is that, when it comes to knowing London, a lifetime of reading in Iowa is no substitute for the lived experience of Washington. Likewise, when it comes to knowing past science, a lifetime of studying the remnants of past science is no substitute for the lived experience of present science.

The revised analogy explains the wariness that some historians display towards scientist-historians. The Washingtonian runs the risk of seeking out everything in London that resembles Washington and ignoring the rest. The Iowan, knowing nothing of cities except what he knows of London, assumes nothing. In addition, the Washingtonian may be enamoured of big cities, in which case he will turn a blind eye to the vices and vanities of London life, and to the tense relationship between London and other parts of the UK. The Iowan will have no such prejudice. The two errors I have just described correspond roughly to the ‘present-centredness’ and ‘triumphalism’ that historians often attribute to scientist-historians.

The analogy has the further merit of showing why we should be wary of these attributions. After all, it is possible for a Washingtonian to study London with an open mind. Only a fool assumes that every city is identical in all respects. We might even say that the Washingtonian is in a better position than the Iowan when it comes to comparing US life to UK life, since he is familiar with both London and Washington whereas the Iowan only knows the former. It is also possible for a Washingtonian to criticise city life. Cities, like sciences, are layered and varied and riven with factions. Washingtonians criticise each-other, so why wouldn't they criticise Londoners? They can empathise with Iowans; why not with East Anglians?

The force of my analogy depends on the scope of tacit knowledge. How much can we learn about London by living there that we cannot learn by reading about London? Analogously, how much can we learn about the practice of physics (or biology, or economics, or whatever) that we cannot learn by reading about it? The force of the analogy also depends on how much science has changed over time, and which parts of past science we study. How similar is eighteenth-century chemistry to today’s chemistry? Are they as alike as Washington and London? Or are they as different as Washington is from Amsterdam, or Nairobi, or Damascus? Washington and Aleppo are both cities, but life in Washington may be little better than life in Iowa as a guide to life in Aleppo.

So my analogy is not a knock-down argument in favour of scientists who dabble in history. It could easily be altered to yield a weaker conclusion. Still, it is an improvement on the image that Weinberg gives us of scientists wandering into an alien land that historians know directly from long experience. Historians do not know past science in the direct way that scientists know present science. And past science is similar to present science. So it is plausible that scientists can help us know past science more directly. Expand post.

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Why historians shouldn't write off scientists: on Steven Shapin's review of Steven Weinberg's Explain the World

Say what you like about the science wars, they’ve got legs. A few days after finishing a review of The One Culture, the book that was supposed to end the quarrels between scientists and sociologists/historians of science, I learned that two of the contributors to that volume have been involved in a new skirmish. The opening shot was a new book by the physicist Steven Weinberg, called To Explain The World. The riposte came from the historian of science Steven Shapin, who has reviewed the book under the uncompromising title 'Why Scientists Shouldn't Write History.' Will Thomas, who drew my attention to the review, comments that Shapin’s review is ‘unduly divisive’ and that historians ‘ought to take seriously...the objections and perspectives of scientists.’ I agree, but I would go further. The reason historians should not write scientists off is not just that the scientist's perspective is valid but also that it overlaps with the perspective of some historians. To a large extent, the division that Shapin sees between scientists and historians is better understood as a division between historians.

The methodology that Shapin endorses in his review is a strong form of anti-presentism. He writes: ‘History is properly about trying to understand the world of the past in its own terms.’ Most historians would agree with some reading of that statement. Most would also agree with Shapin that the job of professional historians these days is not that of ‘judging the past by the standards of the present.’ But Shapin goes further, in two ways.

Firstly, he suggests that historians cannot legitimately say that an earlier event was a precursor to a later event. The true historian will ‘thump the table’ while reading Weinberg’s book, ‘insisting that searching for anticipations and foreshadowings is both wrong and illogical—‘ahistorical’ as they’d say.’ Certainly there are historians who would say this. But many others would say that an anticipation is merely a case of a past event resembling, or having an effect upon, a later event, and that anticipations are meat and drink for any historian who aspires to narrate or analyse past events—that is, for any historian worthy of the name.

Secondly, Shapin seems to say that no-one should judge the past by the standards of the present. That is, such judgements are barred not only to professional historians but also to anyone who wishes to write accurate accounts of past science. Shapin’s subtitle captures his view nicely: ‘Plato was ‘silly’. Bacon ‘overrated.’ Galileo ‘behind the times.’ The suggestion is that anyone who makes such claims has made a fundamental methodological mistake, analogous to affirming the consequent or using a telescope to prove a mathematical theorem.

Again, many historians would agree with this. But what’s wrong with saying that a past theory was false or that a past scientist used an unreliable method to reach a theory? Can such statements be verified? Apparently. Do they inevitably lead the author into errors of historical fact? If you think the answer is 'yes,' I'ld like to know your reasons. Arguably, Weinberg’s error is disciplinary, not conceptual. He has used past science in a way that professional historians do not usually use it, and in doing so he has underestimated the preciousness of professional historians.

Shapin’s blanket anti-presentism obscures the real error in Weinberg’s book. Here I must confess that I have not read Weinberg’s book, so I stand to be corrected. Based on Shapin’s description, however, it seems plausible that Weinberg has judged past scientists by first establishing whether their theories were true or false, and then by assuming that the true ones must be the result of sound reasoning and the false ones the result of incompetence.** Plato’s cosmology does not match our own, hence Plato was ‘silly’; Newton’s cosmology is very much like our own, so he must have been a flawless genius. The problem is not the judging, or even the judging-by-today’s-standards. The problem is judging the rationality of an individual by the truth of their theories. This common error is the reason we have the symmetry principle. In his eagerness to run rings around Weinberg, Shapin skates over the distinction between truth and reasonableness and thereby repeats Weinberg’s mistake.

Shapin’s anti-presentism is tied to his defense of the autonomy and expertise of the professional historian. His target is the dogma that ‘writing history is pretty straightforward and that being a 21st-century surgeon gives you a leg up in documenting and interpreting, for example, theories of fever in the 17th century.’ There are really two dogmas here. The first is that history is a doddle. This dogma is false (though whether history is as difficult as surgery is an open question). The other dogma is that knowledge of present-day science can be useful when studying past science. This is a much more plausible dogma, and Shapin is in danger of replacing it with the opposite dogma that scientists have nothing in particular to contribute to the history of their disciplines.

Shapin reaches this conclusion by analogy. ‘Modern installation artists don’t think they can produce adequate scholarly studies of Dutch Golden Age paintings, and it’s hard to find offensive linesmen parading their competence in writing the history of rugby.’ The plausibility of both analogies is due partly to the fact that installation artists, unlike historians, are not heavily involved in reading and writing argumentative prose. The analogies are suspect because scientists are heavily involved in those activities.

More importantly, the analogies rely on the fact that installation art is not painting and that linesmen are not rugby players. But the question is not whether physicists can help with the history of botany, or whether ethics committees—the linesmen of biology—have something to contribute to the history of biology. The question is whether painters can help with the history of painting, rugby-players with the history of rugby-playing, and physicists with the history of physics. And it seems to me that the answer in all cases is that they can, and they do.

The assumption that lies behind Shapin’s analogies is that present-day activities cannot be compared with their closest equivalents in earlier epochs. Now, we can all agree that activities have changed over time, and that the risk of anachronism is real. But how much have events changed, really? How should we weigh the threat of anachronism against the special insights that a practitioner can bring to the study of their practice? And is there really a trade-off between insight and anachronism? After all, it is possible to believe that the earth moves, or that species evolve, or anything else, without automatically attributing that belief to every past scientist.

Shapin’s vision of history is skewed in other ways. On the authority of Thomas Kuhn, he reports that ‘linear and cumulative progress is a problematic notion.’ Very well – but how can Kuhn or Shapin make this claim without making judgements about whether earlier theories were better or worse than later theories, and has not Shapin foresworn all interest in making judgements about past science? Shapin is right that the notion of progress is problematic for historians of science – but is this because we have shown that science does not make progress, or because we have decided not to address the question?

Shapin says that historians would ‘express bemusement at Mr. Weinberg’s insistence that science advances by rejecting teleology, even as he depicts its history as a triumphal progress from dark past to bright present.’ But is it really so absurd to find purpose in human action and not in brute nature? And is Weinberg really so wedded to ‘triumphal progress’ if he thinks that science went backwards in the Middle Ages, as Shapin reports? This historian is not bemused.

I am not saying that Weinberg's book is flawless. As Shapin points out, it ignores most science apart from physics, all science after Newton, and just about everything that seventeenth-century scientists wrote about religion.** Nor am I saying that Weinberg's errors are unrelated to his eagerness to evaluate past scientists and to find anticipations in past science. What I am saying is that anticipations and evaluations do not lead inevitably to bad history, and that at least some professional historians recognise this. More generally, several of Shapin's criticisms of Weinberg reflect the fact that he is a particular type of historian, and not that he is a historian as opposed to a scientist.

This conclusion raises a question that I cannot hope to answer in this post but that is too important to omit. If historians disagree about how to do history, but agree that scientists sometimes write bad history, how should historians go about improving scientists' history? One answer is that historians should set aside their internecine disputes when dealing with scientists: they should only criticise scientists for errors that the vast majority of historians would recognise as errors. The problem is that this seems to tacitly resolve those internecine disputes in favour of the more liberal historians. If Shapin stops criticising Weinberg for evaluating past scientists, will not Weinberg think that it is OK to evaluate past scientists, thereby writing history that I can accept but that Shapin cannot accept?

Still, there is surely some value in identifying points on which historians agree about the historical errors of scientists. These convergences may not be the whole solution, but they are surely part of it. And in the search for historiographical common ground, I think we could do much worse than the symmetry principle that I mentioned earlier in this post and that I have discussed at length on this blog. The vast majority of historians of science would agree, I think, that we should not assume that past scientists who held true theories did so for good reasons, and that those who held false theories did so for bad reasons. Scientists who make these assumptions should be the first targets of anyone who is interested in raising the bar of popular history of science.


** These criticisms of Weinberg's book are based on the data I had at the time of writing, namely a few hints that Shapin dropped about the book in his review. Weinberg has since denied the charges. This denial does not effect the main point of this post, ie. that the division that Shapin sees between scientists and historians is better understood as a division between historians. Expand post.

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How to end the science wars: a review of Harry Collins and Jay Labinger, The One Culture? A Conversation About Science, part II/II

This is the long-delayed second part of a two-part review of Harry Collins and Jay Labinger, The One Culture: A Conversation About Science (2001). In the first part I argued that we—by which I mean, roughly speaking, scientists and sociologists of science—would more easily reach agreement about science if sociologists acknowledged their past relativism and if everyone was charitable in debate. It would also help if we set aside the interesting but irrelevant question of whether the truth of a belief can (partly) explain the belief. In this post I make three other recommendations: revive the internal/external distinction, or something like it; be clear about how our visions of science differ, if we think they do differ; and beware tacit philosophy of science.

Revive the internal/external distinction. Gravity waves are tiny ripples in space-time created by bodies with mass. In 1970, several experts believed that the physicist Joseph Weber had detected gravity waves in his laboratory. By 1980, no experts believed this except Weber. What changed their minds? One plausible answer is that the experts made many sincere and careful attempts to replicate Weber’s results, and these replications failed. Another answer is that there was only one such failure, and that it was carried out by a physicist who happened to have more polemical skill and social prestige than Weber. The former answer says that the experts followed the evidence, and the latter answer that they followed their most powerful colleague. For want of better terms, let’s call the former an ‘internal’ answer and the latter an ‘external’ one.

I don’t know which answer is the right one in the case of Weber, but we should be mindful of the difference between the two answers, because otherwise the science wars will never end. The reason is that scientists tend to play up internal explanations of true beliefs, whereas sociologists emphasise the external ones. If we do not distinguish between these two kinds of explanation, we will not even be able to characterise this disagreement. Worse, we may end up exaggerating the extent of the disagreement.

Most of the contributors to The One Culture do not make any distinction along the lines of the internal/external one. More often they distinguish between ‘natural’ and ‘social’ factors, which they too often see as synonymous with ‘scientific’ and ‘social’ ones. For example, Michael Lynch takes ‘social factors’ to refer to ‘a range of personal, circumstantial, and institutional considerations,’ and ‘natural factors’ to mean ‘objective reality, nature itself, or properties of the physical world’ (271).

What is missing in Lynch’s distinction is the idea that scientists’ beliefs might result from a third kind of cause, namely experiments undertaken by scientists and the deductions made by them—the meat and drink of internal historians of science. No progress can be made if one party (sociologists) does not recognise, even conceptually, the preferred explanations of the other party (scientists).

When sociologists do recognise the scientists’ preferred explanations, they tend to absorb them into the category of ‘society’ or ‘culture.’ This has the effect of obscuring points of agreement between scientists and sociologists, since scientists do not think ‘experiments and deductions’ when they see the words ‘society’ and ‘culture.’ This is not due to any deep misunderstanding on the part of the scientists. It is just not how the words ‘society’ and ‘culture’ are usually used when talking about science.

The point may be illustrated by a dispute between Harry Collins and Trevor Pinch, on the one hand, and the physicist H. David Mermin on the other. Collins and Pinch wrote an account of early experimental tests of the theory of relativity in which they argued that those tests were inconclusive. They maintained that it was not these tests, but rather the ‘culture of life in the physics community’, that persuaded physicists to believe the theory. I leave the rest to Mermin:

What this means depends, of course, on what ‘culture’ is taken to include. If, as I now understand Collins and Pinch’s intent, ‘the culture of life in the physics community’ refers to the cumulative impact of all theoretical and experimental work bearing on relativity since 1905, then [their thesis] is correct. But their readers...are likely to conclude that the momentum was generated by nothing more than many years of growing more and more comfortable with the [two inconclusive tests].

Be clear about other disagreements. In my previous post I said that the most visible disagreement in The One Culture (about whether the truth of a belief can explain the belief) is not a real disagreement. And in this post I have argued that the real disagreement (between internal and external explanations of true beliefs) is scarcely visible in the book. So, are there any disagreements in the book that are both real and visible? Collins thinks there are, but I’m not convinced.

In a chapter near the end of the book, Collins says that sociologists prefer the ‘rough diamonds’ of science to the ‘crown jewels’ of science. He summarises his point by saying that sociology ‘reduces the quasilogical authority of science’, but really he draws several contrasts that need to be treated separately. None of them pick out a clear disagreement between scientists and sociologists.

Process v product. One of these contrasts is that, whereas Collins studies the early, uncertain stages of scientific debates, scientists such as Weinberg (who seems to be the foil that Collins has in mind in this chapter) emphasise the polished theories that emerge from this process. This is a difference in research interests, not a disagreement.

Skills v knowledge. Collins says that he stresses the ‘assiduousness, experience, skill and virtuosity’ of scientists, and the fact that they are ‘the kind of people whom it makes sense to trust’ because they have ‘the right kind of expertise.’ By contrast, scientists play up their ‘privileged access to reality’ and their ‘extensive store of knowledge about the way the world works.’ Whether this is a disagreement depends, as ever, on how the terms are defined. The disagreement vanishes if scientists say that it is precisely their ‘experience’ and ‘skill’ that gives them ‘privileged access to reality.’ Collins himself suggests that ‘the right kind of expertise’ might consist in making ‘experimentally or observationally based claims’ rather than ‘book-based claims.’ This claim is remarkable for its conventionality. It looks like all that quasi-sociological talk of ‘trust’ and ‘skill’ and ‘expertise’ is really just another way of saying that we should believe what scientists say about nature because they study it directly instead of relying on bookish authorities. In short, Nullis in verbia.

Simple v complicated justifications. Collins says that ‘scientific procedures do not speak for themselves but have to be judged and interpreted’, and that ‘experiments and theories [are] less decisive in bringing scientific controversies to a close than uninvolved scientists and others generally think they are.’ His idea seems to be that the intellectual side of scientific debates are more complicated than scientists make out—he is saying that it is not just a matter of doing one or two experiments and drawing the obvious conclusion. The problem is that none of the scientists in the volume deny this, not even Weinberg. In fact, one of them (Mermin) turns the tables and accuses Collins of giving an insufficiently complex account of the early evidence for the theory of relativity.

Social v scientific education. Collins says that the sociology of science ‘turns the public understanding of science into a matter of social education rather than scientific education.’ What he means is that non-scientists lack the time and expertise to carry out a thorough assessment of the evidence on either side of scientific debates over such things as global warming and genetically modified foods. We rely on the testimony of the experts, which means that we need to decide who are the experts on the debate in question. This is not a trivial problem, especially when the experts appear to disagree. Collins implies that scientists have trouble understanding these points. He should have another look at the following passage from the scientists Jean Bricmont and Alan Sokal:

When confronted with experts, any individual or small group of individuals is in a difficult situation. There is no way to find the time and the means to check even a small fraction of the experts’ assertions. And yet, in many practical situations we have to decide whether or not to trust their claims. How should we proceed? This is a truly interesting and difficult question … [and one where] many sociological considerations become relevant (46).

Beware of tacit philosophy of science. Michael Lynch writes that the science wars are ‘a metaphysical battle fought by conscripts who have limited training in the martial arts of philosophy’ (53). Lynch says that the debate would be improved if the participants recognised that they were arguing over questions that have challenged philosophers for centuries, if not millenia. Some of the questions are metaphysical: do causes and categories really exist in nature, or are they just tools that help us to understand nature? Other questions are epistemological: what is the best way to justify scientific theories, and are our justifications strong enough to give us confidence in the existence and nature of unobservable entities like quarks and DNA?

Lynch is right that these are fraught topics, and that anyone who wants to discuss them seriously should have a least a passing acquaintance with the relevant writings of trained philosophers. However, to judge from The One Culture, Lynch is mistaken if he thinks that scientists and sociologists still see these issues as a major front in the science wars. None of those issues appear in the list of ‘open questions’ that the editors provide at the end of the book (299-300). And, as I mentioned in my previous post, the only avowed relativists in the book are methodological ones.

This reticence is both encouraging and vexing. It is encouraging because it suggests that, pace Lynch, scientists and sociologists are arguing over topics that they have some special competence in, rather than ineptly reproducing the debates of professional philosophers.

The reticence is vexing because it may conceal more disagreements than it resolves. Collins, with his stress on 'skill' and 'expertise', often sounds like an instrumentalist, ie. someone who thinks that scientific theories are great instruments for predicting and controlling nature but who is loath to take the next step and say that the successful ones are probably true. Steven Shapin, for all his asides about the impotence of philosophy, defends a thesis that is nothing if not philosophical, namely that there is no single method that characterises all forms of science. Several contributors imply that the sociology of science has shown that science does not achieve 'certainty', a claim that is both normative and epistemological. If we make such claims then we should be clear that we are making them and that they are, at least in part, philosophical claims. This would not solve the problem of how non-philosophers can reach agreement on philosophical questions. But it would at least clarify where the disagreements lie.

***

The stated aims of The One Culture were to get scientists and sociologists talking to each-other again, and to get clear about their points of agreement and disagreement. The upshot of this review is that the book achieves the former goal but has mixed success with the latter. To sum up my criticisms:

- the editors ignore the main source of agreement between the two parties, namely the fact that sociologists have retreated from their full-blooded relativism of the 1970s and 1980s.

- the editors misidentify methodological relativism as a major source of disagreement. Even Harry Collins admits that the truth can help to explain a belief, and anyway the interesting question is not whether truths can explain true beliefs but whether social factors routinely play a decisive role in the formation of true beliefs.

- The One Culture barely addresses the latter question (about social factors), which is not surprising given that most contributors do not acknowledge the distinction between social and intellectual factors.

- Collins identifies another persistent disagreement, concerning 'crown jewels' and 'rough diamonds,' but this distinction is overdrawn, as we see when we unpack the gemmological metaphor.

- some contributors hint at more substantial disagreements over such things as instrumentalism and the unity of science, but these are philosophical questions that scientists and sociologists cannot resolve on their own.

The good news is that the question about the decisiveness of social factors is a question for scientists and sociologists, and there is no reason why they should not be able to answer it together—as long as they can agree to distinguish social factors from intellectual ones. Expand post.

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