VOX DEI BATE #6

Vox has replied, and his response is substantive. I have to admit that I am surprised to the degree that our thinking is convergent on certain points. I will reply at length to the new observations he makes, but for right now I want to focus on the points of agreement, to make sure that there is no misunderstanding.

(sigh) Hopefully, no one will accuse me of equivocating, but we'll see. Vox writes:

"...(2) Scott's genetic definition of evolution differs from the conventional definition based on fossil-based speciation which one commonly encounters in discussions with pro-evolution laymen. (3) I am not attempting to make a proactive case for an alternate theory of speciation or genetic evolution, I am simply defending my position as an evolutionary skeptic.

I agree with (2), though I note that there is greater cross-talk between those who study genetic evolution and the fossil record than ever before, and that 'molecular clocks' and phylogenetic trees derived from the former tend to accord with the latter within an order of magnitude. Those cases that don't aren't being shoved under the rug, either: they are active areas of research.

I also agree with (3) in the paragraph: Vox's skepticism is entirely a negative argument against the prevailing model, not an attempt to foist an alternative model on the rest of us. What I and some others would like to know is where Vox stands on the the question of whether any account presuming natural causes could prove sufficient. How about it, Vox? Is your skepticism on this point confined to TENS (the Theory of Evolution by Natural Selection) alone, or does it extend to any model which confines itself to natural causes?

Anyway, more Vox:

Second, I wish to note a few points that Scott has graciously conceded. (1) There is no clear evidence of speciation in the fossil record. (2) One cannot claim that the Theory of Evolution by Natural Selection (TENS) is the truth and speak as a scientist. (3) Those who attempt to enlist TENS as proof for things which cannot be tested have left the domain of science."

Gulp! I'm going to offer a caveat for (1), since it could easily be misinterpreted.

I don't think any paleontologist would claim that any particular sequence (A-> B-> C) of transitional forms actually unequivocally documents an episode of speciation. We can't know if A is actually an ancestor of B, or if B is actually an ancestor of C. We have to keep in mind that in individual cases other possible explanations for the apparent transition in question might exist. The population represented by A might've co-existed with B, for example, but flourished in greater numbers earlier in the history of life than B (thus leaving more fossils of greater antiquity), and vice-versa, given the impression that population A was ancestral to B when in fact both shared another common ancestor.

So, yes, no clear-cut case of speciation can be demonstrated in any individual fossil sequence. To put it another way, organisms fossilize, but the moment their populations diverge from others (the speciation event) does not. But the inference that speciation occurs doesn't rely upon individual cases, but upon the entire fossil record, and obviously I am persuaded that the inference as a whole is correct. I suspect Vox does, too! So while in a sense I agree with (1), keep in mind my language lacked the necessary precision the topic deserves, and it should not be taken as evidence that I think the fossil record doesn't support the evolution of species, because I do.

More Vox:

(2) One cannot claim that the Theory of Evolution by Natural Selection (TENS) is the truth and speak as a scientist.

This is true, if one is speaking of 'truth' in a non-tentative, dogmatic way, 'Truth' with a capital 'T', the kind of truth the Nazarene says will set you free. Like I said, I'm not in the truth business. The models we build in science are always tentative, always held provisionally. Individual scientists know better than to suggest otherwise, but (especially in popularizations) they often forget that their enthusiasm for this or that proposition comes across as dogmatic, especially when they are being read by someone who defines his or her self in terms of a belief system. Small wonder we scientists are often accused of peddling our own belief system! Most of the time, Vox, I honestly believe that scientists are innocent of this charge. But, you know, I tend to be hyper-optimistic, as PZ observed.

More Vox:

(3) Those who attempt to enlist TENS as proof for things which cannot be tested have left the domain of science."

I agree, obviously. That doesn't make them right or wrong, of course. It just means that such declarations are not science. It's difficult for pro-evolution advocates to steer a middle course here, given the tendency of creationists to insist that their untestable source of Truth trumps our difficult (but not impossible)-to-test model. Unabashed advocacy is a good political strategy, but doesn't necessarily lead to the best science. I can say with authority that scientists tend to speak far more conservatively in our formal pronouncements---that's just the way science is done. Where we often stumble is in popularizations, and (especially) in public debate with the unscrupulous.

Well, that's enough for now. A future post will address Vox's new claims and some points of disagreement. Many have expressed doubts that anything positive can come from such exchanges. I've certainly been frustrated by some of the commenters at Vox's place, but I also have to tip my hat to Starwind (a VD regular), who has demonstrated more genuine intellectual curiousity on the comments section of this blog than many partisans on both sides ever do---and that's refreshing.