Future, Present, & Past:

~~ Giving itself latitude and leisure to take any premise or inquiry to its furthest associative conclusion.
Critical~~ Ready to apply, to itself and its object, the canons of reason, evidence, style, and ethics, up to their limits.
Traditional~~ At home and at large in the ecosystem of practice and memory that radically nourishes the whole person.

Oυδεὶς άμουσος εἰσίτω

Sunday, May 9, 2010


A recent study on Post Traumatic Stress Disorder (abstract here) suggests that trauma may in some cases cause epigenetic changes which switch on (or off) certain genes, for instance those pertaining to vigilance and defensive behavior, or to the immune system.

A more full account of the research lends some support to the notion that the condition investigated--the methylation or non-methylation of genes-- is unlikely to precede the occurrence of PTSD. This is important. If methylation merely correlated with PTSD, it could easily be an index of susceptibility to the disorder, rather than being itself an effect of the trauma. But, as Sandro Galea, one of the study's authors, notes,
[W]e have evidence for dose response between traumatic event exposure and methylation. The more traumatic events people have, the more methylation changes they have — which of course would [make it] unlikely that the methylation changes preceded the traumatic events.
Galea recognizes, however, that more research is needed before the results are considered established.

When I listened to the NPR report on this research, one word seemed to me conspicuous by its absence. One name, actually: Lamarck.

Lamarck, of course, was the biologist who suggested that species had evolved by virtue of changes in the individuals during their lifetimes; giraffes had stretched their necks and passed on the longer neck to their offspring. Modern further consideration of Larmack suggests that there are mechanisms by which certain instances of so-called "soft inheritance" might transpire, but Lamarck's name is still close to a hiss and a byword amongst many scientists. So it is not surprising that it would be avoided in presenting these new findings, however tentative they might be.

There is a further distinction, of course. The changes Galea postulates are not to the genes themselves, but to the mechanisms by which genes are activated. Still, it is striking to find the mainstream media suggesting that events in the organism's environment might have such an impact. After all, if a gene can be turned on or off on the molecular level by the environment, it is a very short step to saying that the gene in its new state can be passed on, or that a gene might itself be effected by environment.

This is admittedly something of an overstatement. A "short" step can still, of course, be formidable in molecular biology. Moreover, while Lamrackianism is more likely to find a foothold in epigenetic shifts as these, they are not just-breaking news, and don't by themselves constitute evidence for it, though the study of epigenetics and inheritance is still ongoing of course.

One final, more speculative note; Darwinism has recently expanded its influence far beyond the biological, not merely into the sphere of ideas (memetics), but into cosmology. Lee Smolin might be the most famous name here (followed by Quentin Smith) but many physicists now seriously consider the plausibility of cosmological accounts by which universes could be considered "fit" or "unfit", i.e., likely (or unlikely) to survive for long enough to generate sentient life. Smolin points to the similarity between the pre-Big Bang singularity and black holes to suggest that black holes might birth universes. And, since black holes also tend to proliferate in a universe as it gets older (thus letting more and more stars explode, providing the elements that go into making biological life), there is at least a plausible correlation between black holes, duration of universes in time, and the occurrence of life.

There is also an unrelated notion called "Quantum Darwinism," which hypothesizes (and produces some evidence for) the notion that the infamous transition from quantum to classical phenomena transpires by way of a kind of natural selection.

Both these notions are interesting and potentially fruitful. Always, however, looking ahead to the next step, I find myself wondering whether Lamarck may yet have a surprise for investigators of the very large or the very small.

Like many psychiatric diagnoses, Post-Traumatic Stress Disorder is controversial. There are those who oppose psychiatric diagnoses on principle, as a medicalization of what is essentially emotional or existential; to these, PTSD is an even worse offender, in that its political ramifications are many and volatile. Now, who knows, perhaps PTSD will grate on a different set: Darwinists. And maybe even cosmologists. After all, there is little that would be more traumatic than being sucked into a black hole!


  1. Lamarckianism represents a legitimate perception, much as the appearance that the sun revolves around the earth does, but as a theory it has been as soundly marginalized as the geocentric universe. In both cases the perception has some validity but the explanation fails. That doesn't mean either will go away for good. One could, with some special pleading, argue that relativity implies that the earth could be the center of the universe--but not that the sun moves around the earth every day. Just as reasonable a lot of modern biology blurs the distinctions that were made in the nineteenth century.

    DNA methylation changes the phenotype not the genotype. That would be very soft "soft inheritance". It is wonderful that we now know how this works. It explains to us how a muscle cell knows it's not a nerve cell. This also seems to be implicated in many disease processes. It also explains how humans could suddenly start growing so big with just a few nutritional changes (when you grow up hungry you turn off your grow genes). But, strictly speaking, this isn't evolution-Darwinian or Lamarckian.

    I quote Dr. Richards from the article you cited:

    "These studies do not demonstrate inheritance between generations, but they do show that the early nutritional environment in the mice and early behavioral environment in the rat studies can change the DNA packaging on the genome, and that that is 'remembered' in the cell divisions that make the rest of the organism, " Richards says. "But this is not from one generation to another. No one has shown that yet.

    I am still an optimist that we will discover some active ways in which organisms change their own evolution based upon their environment. The rate of evolution no longer seems to be fixed as many mathematical models predicted: it appears to speed up and slow down. Gould famously defended this position in his theory of punctuated evolution. Environmentally determined evolution--beyond selection--makes a lot of sense but so far we haven't found any good mechanism to show that it exists. Modern biology is discovering a world of wonderful complexity. It would actually be more surprising if broad laws like natural selection were not violated in such complexity just as classical physics need to be set aside when one enters quantum scale.

  2. thanks, d., I knew I could count on you for specifics on methylation. I like your comparison between Lamarck and the ptolemaic system. While I don't get the feeling that Gould's P.E. is very attractive to biologists at present, maybe this is only because they are guarding against its giving any semblance of shelter to I.D.'ers. Certainly if PE turns out to be valid, one possible reason might be some version of lamarckianism. But Gregory Bateson made what I still think is a pretty good case for why Lamarckianism is likely to not be widespread--namely, that it would be non-adaptive; there would be too much feedback between environment and genotype. As to my other half-baked speculations (cosmological), even the para-darwinian account is not quite baked, so it's hard to say whether a neolamarckian wrinkle would even make sense.

  3. No question the rule of biology is natural selection. If we do find the occasional Lamarkian exception it would certainly not be dominant. But in biology, making exceptions is probably rule number two.

    I think steady state evolution is a theory on the run. Data just keeps coming in that makes them endlessly have to re time that evolutionary clock. I just recently read a study that showed penguins to be evolving at six times the expected rate. At some point, just like the ptolemaic system, you've just got to rethink the problem. Fortunately we just got a new telescope--genomic science.