Happily ever after

Great podcast over at the Maudsley. My favourite bits:

  • Robert Plomin: “… you can’t come up with a personality scale that doesn’t show about 30% heritability… but it isn’t enough to show it’s all determined. […] I don’t really think the genetics of this is all that relevant myself.”
    Robin Murray, slightly taken aback: “Well this is… is a first.”
  • Rachel Perkins: “But actually I have to say that… it always strikes me as the last resort that you go to, you know… survival value for primitive man seems to be when we run out of explanatory ideas.”

Fodor on evolution

Over the years, people keep proposing theories that go: “what everybody really wants is just …” (fill in the blank). Versions fashionable in their times have included: money, power, sex, death, freedom, happiness, Mother, The Good, pleasure, success, status, salvation, immortality, self-realization, reinforcement, penises (in the case of women), larger penises (in the case of men), and so on. The track record of such theories has not been good; in retrospect they often look foolish or vulgar or both. Maybe it will turn out differently for “what everybody really wants is to maximize his relative contribution to the gene pool”. But I don’t know any reason to think that it will, and I sure wouldn’t advise you to bet the farm.

—spotted over here in an old Mindhacks post.

Natural selection as tautology

From an old email exchange…

Here’s the brief summary of Darwin’s theory (from The Origin of Species – I believe).

  1. If there are organisms that reproduce, and
  2. If offspring inherit traits from their parents(s), and
  3. If there is variability of traits, and
  4. If the environment limits the size of natural populations,
  5. Then those members of the population with maladaptive traits (as determined by the environment) will die out or reproduce less, and
  6. Then those members with adaptive traits (as determined by the environment) will survive to reproduction or reproduce more.

To falsify this you have to assume that premises 1-4 are true and show that 5 or 6 are false. Take proposition 5, for instance. You would have to find members of the population with “maladaptive traits” (whatever those are) who don’t die out or reproduce less. From these definitions alone that seems impossible to me, since if the individuals don’t die or reduce their reproduction, then you can just say that they didn’t really have maladaptive traits. I suggested, therefore, that the theory gives names to things that are observed and that it doesn’t make predictions. You could also show that the theory doesn’t talk about reality as we know it, i.e. the premises (again propositions 1-4) aren’t true, but that seems as difficult.

Apparently Popper said something about how actually it’s not a tautology, or at worst is a useful tautology. I have no idea where. Obviously the interest comes from the likes of fossil records, phylogenetic trees, genetics, etc: perhaps that’s where the tautology disappears.