I have a couple of things in the mental queue for this week, but I’m still playing catch-up from my trip to Texas, so instead you get a really quick comment on last night’s Cosmos. This one was all about the history of the Earth– continents moving, climate changing, mass extinctions– stuff that I know in outline, but not detail. It was, by and large, far enough from my areas of expertise that I can’t say much.
I did think that some parts of it were a little too pat, though. These fall into two categories: just-so stories, and things obvious in hindsight. The former includes the very detailed and dramatic descriptions of the Permian mass extinction (which wiped out 90-odd percent of all species at that time) and the process of human evolution. The descriptions in the show were great, well written and delivered, but they sounded suspiciously definitive. That is, I think they were detailed descriptions of particular models of how the Permian extinction happened, and how our ancestors behaved and evolved, but I’m not sure either storyline is quite as settled in the scientific community as last night’s presentation might’ve suggested. Admittedly, I’m saying this largely because the human evolution story had more than a little similarity to the just-so stories regularly peddled in evolutionary psychology, which triggers an increased level of skepticism for me.
The obvious-in-hindsight part was the story about Alfred Wegener and the theory of continental drift, which was presented in a manner that made his case sound a lot more definitive than it was at the time. He turned out to be right about more or less everything, but at the time that he was drawing ridicule for his theories, the case wasn’t really airtight. He had absolutely no idea of what might be causing the continents to move from one place to another, and in the absence of some mechanism to drive continental drift, well, the idea that continents move is kind of a hard sell. It’s only after the discovery of the mid-Atlantic ridge (through the work of Marie Tharp among others, who got her own brief animated shout-out), studies of magnetic field reversals, and the mapping of plate boundaries via seismology and the like that it became clear that the highly improbable notion of continents moving around was, in fact, true.
This is not to say that Wegener wasn’t treated shabbily– he almost certainly was– but the “revolutionary genius oppressed by conservative establishment” framing is really only obvious in hindsight. In terms of a different science, he seems to have been somewhere between Charles Darwin and Erasmus Darwin, Charles’s grandfather, who wrote passionately about evolutionary ideas in the late 1700’s without a realistic mechanism of how evolution could work. Wegener drew on more lines of evidence than the elder Darwin did, but came up short in the same way. A couple generations later, Charles Darwin nailed the case for evolution with both a mountain of evidence and a clear and convincing mechanism to drive charge over time (as did Alfred Russel Wallace at the same time). Wegener’s story is a little more tragic, as he might plausibly have lived to see his theory vindicated, but it’s not completely outrageous that his ideas didn’t catch on right away.
But again, this isn’t really my field; what little I know is mostly from research done for the book-in-progress, where Wegener gets a quick mention in a chapter about Darwin. I’m also somewhat influenced by reading Thony C.’s recent stuff about hindsight and Copernicanism, which has at least temporarily made me more skeptical about this kind of story than I otherwise might be.
Anyway, that’s all I’ve got this week. Next week promises to have some physics-y stuff for me to talk about, as the end-of-episode teaser included a glimpse of a cartoon Michael Faraday and his magnificent sideburns. so there’s that to look forward to.