Even the Good Guys: Pallen’s “The Rough Guide to Evolution”, and Circularity

This and the preceding three postings clear some important things up, this time relating to top class scientists. When I saw John Hawks at Birmingham I also encountered Mark Pallen whose main claim to fame 😉 is being professor of microbial genomics at Birmingham, but he’s also written the nifty “The Rough Guide to Evolution” (2010) (click image to enlarge).

An ideal gift for anyone except people like me – though actually I found it very interesting

I was pleased to see he mentioned that we seem to have been walking upright even before we left the trees, and as he illustrates an orang-utang upright in a tree, and discusses whether we ever did knuckle-walk, he’s suggesting we were upright before the chimp split. (He points out that Susannah Thorpe, an upright-in-trees supporter, is a colleague of his.) He also includes 4 million years in the range of possibilities for the human/chimp split, and as he’s a professor of genomics we can assume this is because he understands the meaning of the genomic analyses of chimps and humans, apparently unlike those at the NHM London for whom 4mys must never be considered a possibility. As Hawks says 2 Jan 2007: “There have been bigger messes than the Patterson et al. 2006 paper, but not many. Yes, it was yet another paper with a 5-million to 7-million-year-old divergence, but it had so much more!”

Mark’s book has a decent coverage of philosophy, with at the start of the section a big picture of Popper “…who made falsifiability a hallmark of scientific theories”, so no messing around with accusations of “controversy” we’re glad to see. Also, none of that “Scientists need philosophy like birds need ornithology” crap we get from Jones, Singh and Cox. (He also mentions David Hull; in a different section there’s a photo of John Maynard Smith looking very old, though I suppose he always did, and in yet another photo there’s a horse/zebra cross, which has huge patches of zebra with the rest white!) But turn the page from the Popper pic and we find… a box describing the problem of natural selection in terms of survival of the fittest… but fitness is described in terms of survival.

This, Mark says, is a problem because of circular definition. He escapes it by saying relative survival compared to other lineages should be taken into account, but I’m not sure that escapes the circularity. What does solve it though (apart from fitness and natural selection both being defined by number surviving, which is something you can measure) is this: it doesn’t matter if definitions are circular! In encyclopaedias and dictionaries, everything is defined circularly in the end. A theory can be defined circularly too, without linking up much with outside theories, so long as it connects with potential observations in a meaningful way, and is self-consistent. I first heard the circularity thing being applied to Behaviourism – reinforcement and behavioural frequency being defined circularly, I think. Circularity is bad when you want to prove something using deduction. (But of course no good scientist would claim to prove a theory true, now would they? 🙂 ) Logic, of which deduction is one form, is sadly misunderstood and hugely over-rated by most people in its relation to science and good thinking generally. You only need probe them on it to find that out. Of course Popperism and hypothetico-deductivism go together (though it looks like Newton developed it and Whewell named it), and it’s used to deduce hopefully fairly inescapable implications from theories. But it’s only a significant part of the fabric of science, not all of it, and the same applies to its place in thinking in general.

Anyway, circularity is not always a problem. But “The Rough Guide to Evolution” is an excellent book (though not the bits on dinobirds, obviously 🙂 ), employing loads of graphics and explanation boxes on the way to explaining tons of stuff on evolution and related topics such as the history of the thought, people and culture involved with it, extremely nicely.

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