Monday, March 14, 2005


Evolution and

FredOnEverything has a column up about evolution here which raises some very interesting points.

Fred seems to want to stress that he is not a Creationist, regarding Creationism as basically too absurd to merit much of a response, and wondering why evolutionary scientists spend so much time trying to debunk Creationism. He's right - I think the point on which I disagree most with him is that Fred is a hard-core positivist.

Natural sciences like physics, chemistry, astrophysics etc. are blessed with immutable constants and laws, which apply regardless of time and space. The Second Law of Thermodynamics, the gravitational constant, the speed of light all apply regardless whether we are here, on the surface of Jupiter, or at the other end of the universe. That's what makes experiments in physics and chemistry possible - an identical experiment should always have an identical results. Experiments are repeatable, and hence empirical science (using empirical in a strong sense of the word) is possible.

Problems arise when you try to transpose this scheme of science on disciplines like evolutionary biology, or my own subject, historical linguistics, where events do not happen necessarily as a consequence of the workings of natural laws, but contingently - they might just as well not have happened. Quoth Fred:

Consequently, discussion often turns to vague and murky assertion. Starlings are said to have evolved to be the color of dirt so that hawks can’t see them to eat them. This is plausible. But guacamayos and cockatoos are gaudy enough to be seen from low-earth orbit. Is there a contradiction here? No, say evolutionists. Guacamayos are gaudy so they can find each other to mate. Always there is the pat explanation. But starlings seem to mate with great success, though invisible. If you have heard a guacamayo shriek, you can hardly doubt that another one could easily find it. Enthusiasts of evolution then told me that guacamayos were at the top of their food chain, and didn’t have predators. Or else that the predators were colorblind. On and on it goes. But…is any of this established?

In evolutionary biology, contingency is built in the fact that evolutionary changes are the product of random genetic mutations. A mutation darkening the wings of a butterfly would raise the changes of survival for that butterfly (provided it lives in a dark environment) but that does not mean all light-coloured butterflies, or other light-coloured animals would have turned dark in the same circumstances. If that were the case, there would be no evolution proper: there would be no genetic diversity, since a the first mutation happening in the population of whatever primordial organism we're descended from would necessarily apply to the whole population, and so the next, etc. Same with the history of language. A change from the consonant group /mt/ to /nt/ has happened often in many different language families, and the reasons of it may be easily seen: it is easier to pronounce /nt/ because of the greater similarity between the two sounds than /mt/. Nevertheless, that does not explain all the cases where this change has not occurred.

The situation for historical linguists is, in a way, much more dire: any "explanation" of a linguistic change must necessarily refer to actions by intentional agents - speakers of languages. Sound changes occur to make the language easier to pronounce, or to get a message easier across - all explanatory models much, much more fuzzy than the random genetic mutations of biologists, which are at least grounded firmly in the physical world.

So when Fred argues:

Early on, I noticed three things about evolution that differentiated it from other sciences (or, I could almost say, from science). First, plausibility was accepted as being equivalent to evidence. (And of course the less you know, the greater the number of things that are plausible, because there are fewer facts to get in the way.) Again and again evolutionists assumed that suggesting how something might have happened was equivalent to establishing how it had happened. Asking them for evidence usually aroused annoyance and sometimes, if persisted in, hostility.

He is right, I think, but I don't think that needs to be much of a concern to evolutionary biologists. Plausibility - the most compelling account given the facts we have at hand - is as much as one can attain in many "historical" sciences. That doesn't make them any less than physics or chemistry - but the subject matter itself makes the posivist methodology of those disciplines inapplicable.

Fred continues:

As an example, it seems plausible to evolutionists that life arose by chemical misadventure. By this they mean (I think) that they cannot imagine how else it might have come about. (Neither can I. Does one accept a poor explanation because unable to think of a good one?) This accidental-life theory, being somewhat plausible, is therefore accepted without the usual standards of science, such as reproducibility or rigorous demonstration of mathematical feasibility. Putting it otherwise, evolutionists are too attached to their ideas to be able to question them.

Here I disagree - first, the origin of life itself has no bearing upon the validity of evolution. Evolution deals with DNA sequences that are already reproducing and mutating. Many evolutionary biologists probably have their own ideas on how those came about (Dawkins presents some in The Selfish Gene), but I don't think that "chemical accident" is as much as a consensus position as Fred assumes. There's one English biologist who has actually proposed that life originated as replicating crystals, only to have been taken over later by strands of DNA.

I think Fred takes race/intelligence arguments way too seriously when he writes that:

Black sub-Saharan Africans (say many evolutionists) have a mean IQ somewhere near 70, live in wretched poverty, and breed enthusiastically. White Europeans, reasonably bright at IQ 100 and quite prosperous, are losing population. Jews, very bright indeed at a mean IQ of 115 and very prosperous, are positively scarce, always have been, and seem to be losing ground. From this I conclude either that (a) intelligence does not increase fitness or (b) reproduction is inversely proportional to fitness.

I might want to post on these ideas in more detail later, as they are vigorously popularized in Finland by one Tatu Vanhanen (father of the current Finnish prime minister) - and vigorously debunked by almost everyone else. Just for now:

- Before theorizing on any relationship between "race" and "intelligence" you must first define "race" in terms of genetics. The old categories like Blacks, Jews, Caucasians, Asians are not going to do: superficial similarity may mask enormous genetic diversity (and as for that, "Jews" aren't even a racially particularly homogeneous group, many of them having genetic roots from all kind of populations all around the Eurasian continent). The problem is that genetic research of this kind (studying, for example, mitochondrial DNA - which happens to mutate at a regular, clocklike rate, as mitochondria are actually the vestigial remnants of independent organisms, now present in our cells) is just beginning, and often you see large syntheses drawn on the basis of preciously little material. But it seems to me that the research of, for example, Cavalli-Sforza makes short work of obsolete racial divisions.

- Modern man arose about 200.000 years ago in the Rift Valley in Africa. One should expect significant genetic/racial diversity to arise no later than 100.000 years ago, when the first modern humans entered Eurasia. Recall that Native Americans are racially quite similar to Asians, even though the first Native Americans must have entered the new world as long as 30.000 years ago at least (the old date of 16.000 BC doesn't fit with a lot of things, among them the enormous linguistic diversity among Native Americans). Also, there's a lot of mention in the literature, valid or perhaps not, about similarities between various "archaic" populations in South-East Asia (for example, the Wedda's of India, the Andamanese indigenous population, etc.) and Australian aboriginals. The forefathers of the aboriginals may have reached Australia as long as 60.000 years ago.

In any event, if there was a correlation between race and intelligence, particularly one as big as quoted by Fred, you would find such a thing to result in significant cultural differences within the world. Yet - the first significant such difference arose only 10.000 years ago with the advent of agriculture, independently, and roughly synchronously, in East China, New Guinea, the Middle East, Central America and Sub-Saharan Africa. Real, significant cultural and technological differences between, say, Europe and Africa are astonishingly recent. Perhaps one would have to place the breaking point as late as the renaissance. Sub-Saharan Africa did have elaborately organized city-states in modern Ghana, Zimbabwe and along the Eastern coast during the Middle Ages. Writing was not developed in these - but writing is an innovation which happened independently only three times in history (Sumer, China and the Mayans).

If there was any real correlation between race and intelligence, one would expect this to become manifest in culture, technology and civilization sooner than during the last 5-1% of genetically diverse human history.

- The number of a mean IQ of 70 for Black Sub-Saharan Africans sounds, well, plain bullshit to me. An IQ of 70 would pretty much mean you're disabled. Note that it is the average IQ we're talking about: half the population would need to be even dimmer. Encounters I've had with Black people of Sub-Saharan origin convince me that this, well, just can't be right.

When IQ tests give you such results (I should try to dig up where that number comes from), the correct response would be to question the validity of your IQ test.

Fred divides evolutionary theory into three conceptual parts:

The first, chance formation of life, simply hasn’t been established. It isn’t science, but faith.

The second proposition, that life, having arisen by unknown means, then evolved into the life of today, is more solid. In very old rocks you find fish, then things, like coelacanth and the ichthyostega, that look like transitional forms, and finally us. They seem to have gotten from A to B somehow. A process of evolution, however driven, looks reasonable. It is hard to imagine that they appeared magically from nowhere, one after the other.

The third proposition, that the mechanism of evolutions is chance mutation, though sacrosanct among its proponents, is shaky. If it cannot account for the simultaneous appearance of complex, functionally interdependent characteristics, as in the case of caterpillars, it fails. Thus far, it hasn’t accounted for them.

On the first, I agree. On the second, I would put things actually stronger: the fossil record is no longer the only piece of evidence that some kind of evolutionary process occurred - the fact that DNA sequences seem to correspond so well to time-depths established by those must count as another. We seem to have 99% of our genes in common with a chimpanzee - but only 40% or so with a wheatplant.

The third one goes, to be honest, beyond my knowledge of evolution. But there's one very strong argument to stick with natural selection and random mutations: namely, it can produce evolutionary change without either violating the Second Law of Thermodynamics (I know, the sun in the sky provides us with a continuous stream of energy - but also, unsuccessful mutations can be regarded as "chaos" offsetting what appears to be increased order; of course, only successful mutations survive in the long tun) or without proposing some kind of goal-directed process, some sort of vitalistic "energy" of the kind that Teilhard de Chardin proposed. Which would be tantamount to leading us into the realm of the supernatural. In that sense, random mutations and natural selection does not seem to me to be merely "plausible", but, to my knowledge at least, to be the only plausible mechanism, as it is firmly based in what we know about the physical world.

- Merlijn

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