Creationist linguistics: It exists

For many years, my only contact with Creationist linguistics was through a parody – a parody of intelligent design in general more than of Creationist linguistics at that. I’m pretty sure that q_pheevr, the author of “The Wrathful Dispersion controversy: A Canadian perspective“, meant to ridicule Intelligent Design proponents by translating their arguments into a realm where they are even more blatantly absurd than otherwise.

Apparently, that’s still not absurd enough for some real folks out there. I particularly love the knots this guy (Wieland, 1999) has to get into within one and the same paragraph:

I think it is misleading to talk about any ‘evolution of language.’ Changes in language come about mostly from humanity’s inventiveness, innate creativity, and flexibility, not from random genetic mutations filtered by selection. And languages studied today in the process of change appear mostly to be getting simpler, not more complex. […] Perhaps ‘devolution’ of language would be a better term.

His factual errors are only icing:

[…] the Sino-Asiatic language family, which includes Chinese, Japanese and Korean […]

Duursma (2002) is if anything even funnier. 

(With a nod to Anatol Stefanowitsch at Sprachlog (German))

Bred to die

Once every while, some creationist will come along who seems to believe that the fact that animals and humans die represents evidence against evolution. The “logic” is that natural selection should inevitably favour longevity/potential immortality since an infinite lifetime means infinite possibilities for reproduction. I’ve always considered this “proof” a proof of the person’s mathematical illiteracy and little else – after all, with any non-zero death rate, the chance to actually survive that long converges to zero with longish finite lifespans, and so does the benefit from potential immortality.

The last time this argument came up, I used the opportunity to practice my new programming skills, so here’s a little script that simulates mortals and “immortals” evolving within the same population. You can play with the parameters, such as extrinsic death rate and rate of reproduction, and decide whether there is a trade-off to (potentially) living longer in terms of slower maturation (there should be, because that’s what we observe in real animals), and whether there’s a bias in life-shortening vs. life-prolonging mutations (there should be, again). We’re pretending that (potential) immortality is actually physically possible for complex organisms, and in fact that once you’re able to survive 160 years, you might as well be immortal.

Here’s what you get when you run the model with biased mutation rates (.003 for life shortening mutations vs. .001 for life-prolonging ones), and no trade-off, and a rate of reproduction of 0.25 per adult per year. We see that there’s a lot of noise, but on the long run the type which lives up to 57 or so years carries the day. Beyond that age, being hypothetically able to live longer doesn’t carry enough of a benefit for selection to overcome the direction of drift when you aren’t going to live that long anyway:

conflated_youngsters

And here’s what you get when you include a very moderate trade-off: The most-short-lived individuals reach maturity at 4 (1 year before they’re bound to die), while the immortals reach it at six, and intermediate degrees of longevity have varying chances of joining the club when they’re in between. In effect, this represents about 10% later maturation per doubling of lifespan, which looks like a very fair deal, but alas this is enough to clearly favour the shorter lived variants over immortals:

percentages_tradeoffandbias

Code below fold. Don’t tell me it’s slow, but feel free to tell me how to make it faster: Continue reading