How Do We Know?
I happened on an interesting show on tv last night, by way of that dreaded vice of idly flicking through some channels without any particular goal in mind. I thought it was Nova, but upon going to the Nova page to find a link and being unable to, discovered that it was something called Secrets of the Dead. Not a very alluring title. Sounds like something on one of those odd channels, one of those channels full of cop chases and other lurid items. But in fact it was quite good, and I ended up watching though I had thought I was going to wander off again after a few minutes. It was about the 1918 flu. There were some mildly irritating aspects, such as unnecessary re-enactments to supplement the archival photos and film, but that's a small point.
The most interesting part, to me at least, was toward the end, when questions of evidence and how to think about them and what to decide came to the fore, and we were presented with two scientists, both apparently quite reasonable and sensible, drawing rather different conclusions from the same evidence. Nothing remarkable in that, it happens all the time, and that's why it's so interesting. It was a very good little lesson in how both science and history actually work, there on our tv screens.
One researcher, an Oxford virologist (whose name I've forgotten), had and has an idea that the flu originated earlier and elsewhere than the generally-believed spring of 1918 in US military camps. So he searched the literature, and found a contemporary article in the Lancet by several military doctors about a virulent respiratory outbreak in a military camp in Etaples, in northern France. The doctors said it was not quite like ordinary bronchitis nor like ordinary pneumonia; they called it 'purulent bronchitis.' It was frequently fatal, and it produced the same 'heliotrope cyanosis' that the 1918 flu did. The Oxford virologist looked for three enabling conditions for a flu like the 1918 strain: pigs, live birds that humans have contact with, and crowded conditions; he found all three.
But that's all the evidence there is. He and others have been looking in permafrost for genetic material that would clinch it, but so far they have not found any. And that's where the two different takes come in. The Oxford virologist is convinced that the Etaples outbreak was the origin of the 1918 flu. But part of his argument for why he thinks so and we should think so too was a little bit odd (and, so, interesting as part of as it were epistemological psychology). He said something like 'How can we just ignore the findings of the doctors who wrote the Lancet article, who risked their lives to do the research? We can't just say they were wrong, we can't just dismiss them.' That's an odd thing to say because it's not necessary to say they were wrong, surely, and even if it were that would not be an argument! Obviously enough.
The virologist then went on to say that the preponderance of the evidence was in favour of the Etaples idea; that it wasn't proven, but the evidence was heavily in favour. His colleague Jeffrey Taubenberger, a molecular pathologist, put it quite differently. He simply said we don't have the evidence, and that's that.
Clearly the two are considering different kinds of things to be evidence, and it's also somewhat clear that the virologist is letting himself persuade himself. That he's taking what one might call circumstantial evidence to be firmer than it really is, and not being tentative enough. And that in itself is quite interesting. The difference between the two is a nice illustration of what lab technicians, journalists, detectives, historians, molecular pathologists and virologists do every day, all over the planet. Figuring things out.
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Ophelia Benson - 3/4/2004
Boy...tell me about it. That 1918 flu was not a good way to go. Asphyxiation.
Ophelia Benson - 3/4/2004
Ah, that's a whole aspect I missed, no doubt because I don't know enough (i.e. anything) about either discipline. That makes it all the more interesting.
Michael C Tinkler - 3/4/2004
I'm glad my pulmonologist four years ago was a nice man and worked hard, but I'm more glad he was up on recent antibiotics and cured me.
Richard Henry Morgan - 3/4/2004
The virologist knows that some viruses are near impossible to culture (he seems to take clinical observation evidence more seriously). To the molecular pathologist, if the material remains ain't there, then there ain't no evidence.
Reminds me of Peter Duesberg, a member of the National Academy of Sciences who, in a case without precedent, was denied publication in the PNAS. His crime? He pointed out that the HIV hypothesis for AIDS hadn't been established by Koch's Postulates, but that amyl nitrate use was heavily associated with Karposi's Sarcoma in AIDS patients. He took a lot of hits, lost funding, and only years later did they fund studies showing that amyl nitrate does indeed cause Karposi's Sarcoma -- in AIDS patients. Duesberg, apparently, was right on at least that part.