Saturday, January 17, 2009

Miller’s Mixed Bag I: Making evolution more impressive than I thought, but still overestimating Evolution

This is part 4 of a five-part review of Kenneth Miller's Finding Darwin's God.

Miller opens chapter 1 with a concise overview of evolution: the range of variation within domesticated and wild species of plants and animals; AND “all living things are engaged in a struggle for existence” (p. 7-8). The result: “This struggle, combined with variation, results in natural selection.” (p. 9a)

From there…

When forces divide a single species into two populations, natural selection will act on each separately, until they have accumulated enough differences that each becomes a separate (and new) species. (p. 9b)

This is the first instance of Miller’s inflation of evolution. As he notes, the “building blocks of this theory” were/are “obviously true”. And “natural selection will act on each separately”—by definition. So, there could “accumulate enough differences” to become a new species. But is that story sufficient for any given speciation? More broadly, to what extent do we expect this story to hold—or at the extreme, what is the probability that it did so for all species? In a nutshell, “could” does not mean “would” or “did”.

I must say that Miller provides some impressive examples of speciation (p. 47, 108-111). So, we have a few examples—and presumably more beyond that. But is that sufficient to believe in the comprehensive story/explanation? As in the case of trying to interpret the fossil record, there are (huge) gaps. So, at what point, should one leap to the inference that Evolution could or does “explain” the origins and development of all life?

Miller seems to recognize at least some potential for doubt. “Evolution’s opponents would argue that the Darwinian mechanism of variation and natural selection is not sufficient…” But he also admits that his “first reaction to such claims has always been puzzlement” (p. 48).

Then, we’re back to confusing can vs. did and would.

…[mutations] can change each and every one of these characteristics…they can produce any change that evolution has documented… (p. 49a)

They can, but did they?

Then Miller wrestles with another argument:

The opponents of evolution never deny that mutations produce variation, but they do argue that mutations, being unpredictable in their effects and random in their occurrence, cannot produce beneficial improvements for natural selection to work upon. (p. 49b)

Cannot? No. Perhaps they would claim or imagine “cannot”—or probably would or did not—on a systematic basis (or completely). And as for the key question: did mutations accomplish X, Y and Z—and if so, where’s the evidence?

A few pages later (p. 53), Miller draws an important distinction: evolution as mechanism (what an opponent of evolution would call “micro”) and evolution as history (“macro”). But then, he makes a bizarre set of claims about the latter:

In this respect, evolution is as much a fact as anything we know in science…It’s true that the historical record is incomplete, subject to interpretation, and open to revision…Evolution is a fact. (p. 53-54)

Huh? Incomplete and subject to interpretation and revision. That’s what he calls “fact”? As good as anything we know in science? (Insert obvious counter-example here.) And how can anything in far-off history be as factual as a contemporary observation?

This unusual view of history is a reprise from claims earlier in the book. Can history be explored scientifically? (p. 22, 28a) Sure. He provides an interesting example on the history of “pop-tops” for soda and beer cans (p. 28b-31a). But the example mostly underlines the competing claim—because a.) his pop-top narrative is far too tight given the available evidences (fitting, given his willingness to leap to inferences with spotty data); and b.) pop-tops were rooted in a recent history that is well-rooted (in comparison to what we know about what happened eons ago).

I think he incidentally reveals the problem at the start of the next section:

“..evolution is really a story of logic extended backwards into time” (p. 31b).

Exactly! It’s a story more than an explanation. It is the logical extension of the story as an attempt to interpret and explain the past. But how, on earth, can that be considered “fact”?

Then a few pages later, we read more of the same:

Evolution is partly the story of how the present is linked to the past, the story of what happened…It is beyond the scope of this book to present anything close to a complete account of the history of life. [Nice “strategy”!]…As any sane historian would argue, you don’t have to retell all histories in order to get a sense of what history is really like. Whenever new cultures and civilizations appear…we can find their roots in the immediate past.” (p. 37)

But a sane historian would also know how much confidence to put into a highly incomplete history, especially one looking back hundreds of millions of years.

Aside from insane historians, Miller has two other primary targets:

First, Miller diminishes Gould & Eldredge’s theory of “punctuated equilibrium”. (Again, nice “strategy”!) G&E’s PE model attempts to “explain” gaps in the fossil record—or more accurately, questions gradualism’s ability to explain the fossil record. In doing so, G&E at least implicitly embraced an even more aggressive “hand-waving” mechanism—moving from “well, evolution did it” to “well, evolution with some weird historical circumstances did it”. Contra Miller, by any objective account, if true, it is a significant departure from the gradualism required by Darwinism. And the fact that a theory like that has any currency is emblematic of Evolution’s (current) limits.

Second, Miller takes Philip Johnson to task for his macro/micro evolution distinction: “Johnson is careful never to give this term an exact definition…” (p. 108a). Whatever the merits of that complaint, it must be weighed against the decision of Miller and others—to consistently conflate evolution as history and mechanism.

Miller also complains that Johnson attacks evolution without proposing anything better (p. 123). True enough. Johnson has always focused on diminishing Evolution to what he sees as its true (and limited) explanatory power. I don’t know if Johnson is just trying to stay focused—or doesn’t, reasonably, want to stray beyond areas of expertise. Perhaps, as Miller claims, this is just one more clever or even nefarious “strategy”. But I think one might easily imagine Evolution as the best thing going, without being much impressed by it as a comprehensive explanation.

By analogy, imagine that a historian had spotty evidence that something occurred a long time ago. Other historians might see his theory as the best current explanation without having a lot of faith in the explanation itself—or imagining that a full, satisfying explanation would ever be possible.

An irony here is that the failure of one or both sides of this debate may be more imagination than science. Perhaps Johnson and I are wrong because we simply can’t imagine that evolution the mechanism is roughly equivalent to Evolution the history. Or perhaps Miller is wrong because his imagination toward Evolution as history is far too fertile.

At least intellectually, I can see where people would have different levels of different types of evidences—and weigh them differently—leading them to draw different inferences. But Miller seems to lack some imagination here too—unable to see how this could occur, at least honestly. Putting it another way: sometimes it’s difficult to imagine how one could not be impressed by the evidence—whether in religion, economics, science, etc. But it happens—and sometimes (even often), from honest disagreements.

As Miller puts it:

…the demands for a mechanism made by latter-day creationists (sic) like Johnson collapse into what has been called “the argument from personal incredulity”. The only compelling case they can make against evolutionary theory is that the mountain of historical and experimental evidence supporting evolution hasn’t yet convinced them.” (p. 111)

Miller finds this highly unsatisfying. But at the end of the day, “the mountain” is more like a mole-hill—at least relative to what one would need to confidently believe in Evolution as history, as a comprehensive explanation for the origins and development of life.

Miller observes, rightly, that:

We could, if we wished, hold up the origin of life itself as an unexplained mystery, and find in that proof of God at work. Since neither I not anyone else can yet present a detailed, step-by-step account of the origin of life from nonliving matter, such an assertion would be safe from challenge—but only for the moment. (p. 276).

But the flip side of his reasonable claim here is that so much is not yet known.

Miller mostly tries to understand those with whom he disagrees—and asks the same of others on all sides of this debate. This is laudable. But the debate is riven and driven by uncertainties and extrapolations. Therefore, it should not surprise him that the lack of data, the unwillingness to jump from evidence by faith to inferences, the extra noise from extremists, the worldviews which influence our views on this topic, and so on—that all of this would make clear consensus ever so elusive.

And if there’s no hurry, from a Christian or scientific point—to claim that Evolution as history explains some or much—why go there? Or if God can intervene—as Miller argues—why insist on necessarily excluding Him from every example of speciation.


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