Saturday, November 21, 2009
Anyway, he seems to be back to blogging, now at the NYT, and his blog is -- at least as of now -- a lot better than his columns.
Saturday, November 14, 2009
On the whole I'm unconvinced that the problem is a good one for a mathematician (or physicist) at present, although -- like all semi-masturbatory projects -- it might stimulate developments in pure mathematics. The hard part is not finding an algorithm that generates "life" from the "primeval soup" for some definition of life and primeval soup; it is finding one that gets the gross features of real primitive life right. The existence proof is not the issue. One needs to think harder about testability than Gowers seems to want to: there are probably a gazillion different automata that give structures that are lifelike, but are any of them relevant to what happened in the primeval soup, and how would we know?
It's not obvious, either, that there is a math-problem/toy-model/"universal" aspect to biogenesis. As I understand the rough story, it goes something like this: given a primal soup with appropriate ingredients and dreadful weather, you can form (with some finite probability) a very primitive self-replicating strand of some (probably zipping) molecule. This is more or less what the Miller-Urey experiment suggests. The gaps in this story are essentially about rates -- would the amino acids survive for long enough to run into each other, what's the lifetime of an RNA strand, etc. -- and have no math content. The next question is how an RNA strand turns into a self-replicating proto-cell. Once again, this is mostly a question of rates; it's clear that a cell is more stable than a strand, once formed. There's a whiff of universality here -- for some simplified model of e.g. 3 cell ingredients, a spherical cell ingesting amino acid at a constant rate r etc., you can ask what the conditions are for life to be stable for long enough that cells can diffuse out -- they're unlikely to be motile at first -- into new environments before they suffocate in their own waste. In principle this might give you constraints on the origin of life. However, it seems exceedingly unlikely that a model of this kind would make testable nontrivial predictions. To get any further one would have to separate the essential and accidental features of the most primitive cells, and I'm not sure we're in a position to do that. The simplest organisms still existing today are wildly unrepresentative being the ones that survived.
The banalities come from a gimmick that can be called the Straw We. First Gladwell disarmingly includes himself and the reader in a dubious consensus — for example, that “we” believe that jailing an executive will end corporate malfeasance, or that geniuses are invariably self-made prodigies or that eliminating a risk can make a system 100 percent safe. He then knocks it down with an ambiguous observation, such as that “risks are not easily manageable, accidents are not easily preventable.” As a generic statement, this is true but trite: of course many things can go wrong in a complex system, and of course people sometimes trade off safety for cost and convenience (we don’t drive to work wearing crash helmets in Mack trucks at 10 miles per hour). But as a more substantive claim that accident investigations are meaningless “rituals of reassurance” with no effect on safety, or that people have a “fundamental tendency to compensate for lower risks in one area by taking greater risks in another,” it is demonstrably false.
On the other hand, the structure described here is a paradigmatic strawman argument. One rarely knocks down a straw man for the sheer pleasure of it. The point of strawmanning is to introduce a counter-assertion that can be defended narrowly -- the "trite" version, which only an idiot, i.e. straw man or Gladwell's typical reader, would disagree with -- but is meant to sound like a broad (and usually indefensible) statement. And I must say that Pinker's evident irritation gives me some pleasure: this is, after all, a guy who straw-manned all of Western thought in The Blank Slate.
PS Gladwell's "igon values" reminded me of this old running joke Grobstein and I had about eigenworthlessness.
Friday, November 13, 2009
I need not explain why I was reading a list of school reunions, when my eye fell on what follows: the address of a girls' school in Llandudno, and the notification that it was the "Final Old Girls' Reunion". Next April it will occur; the information tolled in my ears: why is it the last, how can anyone know? It may be that the organiser has just got tired of doing all the work: that fewer and fewer old girls are turning up, that some of them are shrill and grubby and have vodka bottles in their bags, and piercings, and toyboys in tow: or that Llandudno is just too hard to get to. But sadder explanations suggest themselves. Are there only two old girls left, and has one of them been given a bad prognosis? I can't help thinking what it would be like, two sassy old dames crumbling a final scone together, replacing in its saucer the teacup drained of Darjeeling, polishing their noses with a crumpled tissue: "Well, Blinky, old thing . . ." "Well, Nodders, old girl . . ."; brushing crumbs from their laps, laying down the final butterknife, stepping into separate taxis to go their final ways. Surely there's a short story in it. But it's not mine, is it? It's one for Jane Gardam.
Wednesday, November 4, 2009
I had a thought for no one's but your ears:
That you were beautiful, and that I strove
To love you in the old high way of love;
That it had all seemed happy, and yet we'd grown
As weary-hearted as that hollow moon.
Are they better described thus:
The plainest, most straightforward language in the poem, in some ways, comes at the very end—final words, not uttered in the conversation, are more private and more urgent than what has come before. ... That closing passage of interior thoughts [...] makes the poem feel, to me, as though not simply heard but overheard.
or like this?
... how artificial Yeats's manner of writing was. As a rule, this artificiality is accepted as Irishism, or Yeats is even credited with simplicity because he uses short words, but in fact one seldom comes on six consecutive lines of his verse in which there is not an archaism or an affected turn of speech.
Monday, November 2, 2009
As for how this fits into the larger picture, it's of no consequence whether Darwin or Wallace came up with the theory of evolution, or whether Darwin was a crook. But it's always seemed to me -- and here of course I differ from Davies -- that Darwin/Wallace get way too much relative credit for their contributions to evolutionary theory. The story as I see it goes something like this:
1. Early 1800s geologists find out that the geography of the earth changes over time, sometimes relatively fast. The earth appears to be pretty old. Native species seem well-adapted to their changing environments; this is implausible in the extreme if everything was created at once. Therefore, some sort of adaptation must happen. Also, there are fossils.
2. The species native to some (old) islands are highly distinctive, whereas those from recently isolated islands are similar to the mainland varieties. The pattern of similarities in archipelagoes, in particular, -- Indonesia, the Galapagos -- seems strongly suggestive of a common ancestor from whom the varieties diverged over time because they were isolated. This gets you the "descent with modification" part.
3. A half-assed analogy with Malthus leads to the claim that descent with modification is due to "survival of the fittest" while competing for scarce resources. This claim was largely unsubstantiated (it's more a conjecture than anything else) and had huge problems, e.g., that with "blending inheritance" -- the naive belief that characteristics "blend" during reproduction, which I think everyone believed at the time -- mutations are unlikely to survive.
4. Gregor Mendel discovers that inheritance is particulate rather than blending, i.e., that black + black = white 1/4 of the time, and basically invents genetics. I don't know if Mendel thought about the implications for evolution, but this is really the key point that makes natural selection work.
5. 20th-century geneticists -- people like Morgan, Fisher, and Haldane -- turn genetics into a proper experimental science and construct the theory of evolution through natural selection, or, if you like, prove Darwin's conjecture using Mendel's theory.
In terms of importance I would rank these 4-1-5=2-3 -- and that's without discounting 3. as derivative of Malthus. First of all, 3. is conceptually shaky without 4., and vague besides; this is evident from e.g., the fact that the next major advances in evolutionary theory came through 4. via 5. This is rarely the case with true scientific breakthroughs. Second, I feel like 4. would have led immediately to 3. once people started taking Mendel seriously. This is because 1. and 2. had opened up the question of the variation of species (which is why they are important advances).
It would be a gross exaggeration to say that Darwin discovered evolution like Democritus discovered atoms, but not, I suspect, a complete falsehood.
PS Wallace was a spiritualist and a teleologically minded type so it's probably a good thing he didn't grow too influential. Besides, he was no Marsellus Wallace.