10/09/2007

EXPOSING VOX'S INNER RAT


Naked, naked, naked.

Sorry, but I just had to say it. I attempted to download a wikipedia commons image of the naked mole rat through my school site computer (thankfully up and running again after a fight in my classroom). Apparently, that was too much for my school district’s firewall: the search ‘naked mole rat’ was denied and a record of my looking for such "has been logged."

Gasp! Naked mole rats, naked, naked naked----you’d think I’d stumbled on something obscene! Please don't tell the Society for the Prevention of Rodent Nudity.

(Just for the record, my chemistry students probably feel that it is the mole itself, rather than any nudity, that is so objectionable—especially after about 70 percent of them failed their first test using moles. But I digress....)

Anyway, why naked mole rats? Turning back to Vox’s last post in our exchange, he’s uncovered some (gasp!) cognitive dissonance in the example of the naked mole rat which, as NCSE trumpets, is a model example of an evolutionary ‘prediction’. Yet another reason for his famous 'intuition' that there's something wrong with TENS* to manifest itself, you see.

For those of you who are unaware, the naked mole rat is an unusual mammalian species that shows a pattern of societal organization (eusociality) more like that seen in ants and social wasps than in other mammals. The entomologist Richard Alexander (shown on the right) rather famously predicted (among other things) the functional ecology that might lead to a mammalian species exhibiting eusociality, even though:

a) he was no expert on mammals, and

b) no such species was known to exist.

This off-hand prediction was made while giving a talk at Northern Arizona University (Flagstaff) in the mid-1970's. A mammalologist on the faculty suggested that a South African rodent (Heterocephalus glaber, the ‘naked mole rat’) might be the beastie Alexander had in mind. When the matter was investigated by Jennifer Jarvis and other field workers in the early 1980's, H. glaber was found to fit many aspects of Alexander’s clever extrapolation, including eusocial behaviour. The latter is noteworthy because nothing appears to have been known about the social behavior of H. glaber when Alexander made his prediction!

A very nice success story, but Vox is back to rain on the parade. Further research now questions the extent of eusociality within H. glaber, such as the fact that some individuals are still doing things to maximize their individual fitness---as Vox, quoting Sherman, writes: "There's conflict of interest; there are individuals still striving for their own reproduction at the expense of others under the surface of this amazing apparent cooperation."

Well, gee, Vox. Alexander, Jarvis etc. never claimed otherwise. The prediction had to do with what sort of functional ecology could select for eusociality in vertebrates, not whether or not a mammal would behave as a 'superorganism', which is something of a disputed trope within biology, anyway. Even the social wasps that inspired W.D. Hamilton (shown on the left) to propose a genetic basis for kin selection are, in a sense, seeking to maximize their individual fitness. In fact, the non-reproductive females that 'practice' haplodiploidy arguably have greater fitness than, say, Wilt Chamberlain.

Vox also notes that many of the other features 'predicted' by Alexander could've been in the literature at the time of the prediction, in effect encouraging us to entertain the unpleasant prospect that Alexander might've been aware of same. Possible? I suppose, but far from probable. Like a lot of non-biologists, Vox really doesn't have a handle on the true diversity of life, and thus fails to understand how improbable that Alexander, an insect guy, would be able to stumble on just the right vertebrate species in advance that have just the right characteristics.

Consider the sheer size of the data set that Alexander would have to look at. Even if you delimited it to the vague requirement of being 'a burrowing mammal' there would still be 22 species of blesmols (African mole rats) in 6 genera alone. There are another 25-30 species of 'mole rats' among the Spalacidae, at least 35-40 species of gophers, 5 species of prairie dogs, 15 species of marmots, etc. Don't even get me started on the (literally) hundreds of species of nocturnal, burrowing rats and mice. It's a bit much to suggest that Alexander could've just happened to have dabbled in the rodent literature and pull out a species that was reminescent of the social insects he studied. And, in any case, the truly novel prediction was for eusociality in vertebrates, and that was pretty much unexplored territory at the time.

Why would Vox strain our credulity with this argument? Because he's wedded to the incorrect idea that TENS, as a 'historical science', simply doesn't make testable predictions that can be compared with those of, say, engineering. What he misses is the fact that TENS is not confined at all to historical explanations, but provides us with all sorts of testable predictions in the here and now.

Consider, for example, the field of classification. Historically, evolutionary biologists who worked in systematics built trees that inferred relatedness from the degree they shared or differed in various morphological features---which is to say, the phenotype. When comparative genomics became possible, the phylogenetic trees constructed based on genotypic similarity were, in effect, an independent test of those earlier models. In the main, the pattern inferred in previous generations by comparative anatomist and paleontologists is confirmed by the molecular biologist---but there have been, and continue to be surprises. These are falsifiable claims, and metaanalysis of the degree to which trees derived from different data sets depart from one another constitute independent tests of the entire process.

One could argue, I suppose, that all the data sets either assume or purport to demonstrate common descent, but surely Vox is not proposing that the scientific evidence supports any other conclusion. Nor does he have any other conclusion, or any other model that he wishes to share. He just has an 'intuition', and his supporting argument about lack of predictive power misses the point entirely. Chemists can't predict the final folded shape of most proteins with the degree of accuracy demanded of engineers, either, but I don't see anyone suggesting that chemistry is not a science, or a metaphysical dodge, or a paradigm whose shift is overdue!

* My personal shorthand for 'theory of evolution by natural selection'.

2 comments:

Anonymous said...

Scott,

It appears that your "debate" with Vox has dribbled down to nothing, so I will likely not darken your comments section further.

With this post, I think you have probably won by a technical decision, i.e., on points. I was disappointed that Vox's argument was not as rigorous as I had expected.

Not that I expected his approach to convince you, but I thought his reasoning along this path could have been tighter; at least it could have been more self-contained and drawn a definite conclusion.

I don't think your status as the "token faithhead" is all that remarkable, but maybe it will impress some of the more cynical participants (pro or con) in discussions of TENS. To go further in that direction, it seems like you should present a more intricate reasoning concerning your faith.

I think the greatest service you are doing for the community of TENS advocates is being fair and honest. For example, it seems to be really difficult for many of them to admit the distinction between an inference and an observation, but you are very clear on this point.

Best wishes,

--emerod

Scott Hatfield . . . . said...

Emerod, thanks for your comments. They are perceptive. In the main, I agree, though I do believe that my failure to maintain my previous pace of deviltry also led to flagging interest. I had many more visits when I was haranguing Vox's many wanna-be clones than when I focused just on my site.

I do hope you will visit again. I do intend to further explore my own faith commitments and the limits of that perspective in the series of posts entitled 'Behind The Curtain'. I next intend to post on the internal coherency or lack of same in belief systems, having already talked about external coherency.

I think the problem with Vox's position is that it was intended to skirt rigor, rather than define it. Vox is not a natural scientist, and he did not want to present a view that could be ridiculed on the basis of science, lest that be used to undermine his standing as a commenter on the cultural wars---which is, after all, his real interest. His is a rearguard action that attempts to maintain respectability by acknowledging the scientific consensus while attempting to imply that room might yet be found for a theistic understanding in science, or (if not) that some sort of redoubt can be credibly maintained for some version of Genesis-Just-So, free from the inconvenience of facts.

As a theist, I can well sympathize with this goal. As a scientist, however, my status as a 'faithhead' (token or otherwise) can in no way be justified. I would probably be in a much 'safer' zone emotionally and intellectually if I pretended that the consequences of belief systems, as with belief itself, is not subject to scientific review. But it would also be less interesting.

As for the distinction between inference and observation, I cheerfully admit that if this were a public debate I would gloss over this distinction, because it plays to a trope that is perceived as a 'weakness' of science, namely the acknowledgement of our own uncertainty. Is this intellectual dishonesty? Perhaps, but you must remember scientists have history with the creationists, history that in a formal setting makes all sorts of bad arguments on their behalf difficult to counter, precisely because they dishonestly exploit the integrity of science as it is actually practiced.