Sunday, April 17, 2005

Nelson on Sober on Gould

Our story begins with this article from The Missoulian, a Montana newspaper. The subject is a talk given by philosopher Elliott Sober at the University of Montana:

“The theory of evolution is not an atheistic doctrine,” Sober said. “It's about life once it gets started. How the universe began is not a problem for biologists. It's a problem for physicists.”

Sober presented two famous cases against and for God's involvement in designing the world.

In what he called “the panda's thumb,” Sober recounted science writer Stephen Jay Gould's observation that the small knob of bone on a panda's wrist, which it uses to prepare bamboo for eating, is so inefficient that it argues against an “intelligent designer's” involvement.

That argument is false, Sober said, because it assumes we know what God was trying to do with the panda's thumb. Nature is full of imperfect creations as well as remarkable ones. But we have no way yet of learning God's motives, if there are any.

It's always difficult to glean what somebody said from a brief newspaper account. As it happens, however Sober has elaborated on this point in other writings. (PDF format)

Sober's broad point is correct. If we hypothesize a deistic God who created the world but no longer interacts driectly with it, then it is impossible to know anything about His motives.

The problem with Sober's argument is that Gould pretty clearly was not trying to make an argument for atheism. Here's what he actually wrote:

Our text books like to illustrate evolution with examples of optimal design--nearly perfect mimicry of a dead leaf by a butterfly or of a poisonous species by a palatable relative: But ideal design is a lousy argument for evolution, for it mimics the postulated action of an omnipotent creator. Odd arrangements and funny solutions are the proof of evolution--paths that a sensible God would never tread but that a natural process, constrained by history, follows perforce. (Emphasis added)

Those bold-faced portions are important. By using the term “postulated” Gould is making it clear that he is, indeed, making certain assumptions about God. Those assumptions are that God is all-powerful (stated explicitly) and all-loving (implied throughout the essay). These are very common assumptions to make about God. And given those assumptions, the odd-design of organisms becomes something that is awkward for theists to explain.

On the other side of the coin, if we hypothesize that complex structures arise by gradual accretion and natural selection, then we would expect those structures to bear evidence of history. A panda with a fully opposable thumb that is lacking in its nearest relatives is hard to explain via evolution. But a panda whose thumb is cobbled together from bones serving other purposes in the panda's closest relatives is exactly what you expect from evolution.

I notice that Sober has mostly acknowledged this point:

Gould’s argument, I hope it is clear, is a likelihood argument. I agree with what he says about evolutionary theory, but I think his discussion of the design hypothesis leads him into the same trap that ensnared Paley. Gould thinks he knows what God would do if he built pandas, just as Paley thought he knew what God would do if he built the vertebrate eye. But neither of them knows anything of the sort. Both help themselves to assumptions about God’s goals and abilities. However, it is not enough to make assumptions about these matters; one needs independent evidence that these auxiliary assumptions are true. Paley’s problem is also Gould’s. (Emphasis in original)

As I have already shown, Gould was perfectly aware that he was making assumptions about God's character; he has not been ensnared in any trap. Sober has no basis for saying that Gould thought he knew what God would do.

We could go on for many pages on this subject, but let's bring Paul Nelson into this. Some years ago Nelson managed to con the editors of the academic journal Biology and Philosophy into publishing a bit of poorly-reasoned tripe called “The Role of Theology in Current Evolutionary Reasoning.” The focus of this paper was Gould's essay.

Commenting on Sober's Montana appearance, Nelson writes:

The scientific establishment retails a great deal of high-minded advice about the proper relationship of science and theology. Typically this advice recommends a “non-overlapping spheres” model, according to which theologians with good manners stay on their side of the playground, in a thin strip of weeds near the gymnasium wall, while scientists stay on their side, which turns out to be the rest of the playground. Stephen Gould’s “non-overlapping magisteria” (NOMA) framework is an instance of this notion, and one wishes Gould had followed his own advice. But he played in the theologians’ tiny patch of weeds as well. Threw his weight around, in fact.

Sober rightly indicts Gould for this deep inconsistency. The panda’s thumb argument amounts to a hopelessly contradictory methodology. “Strict NOMA for you, but any argument I like for me, including helping myself to that theology buffet over there.”

We should begin by pointing out that no one has actually said that last sentence. Nelson places it in quotation marks for no reason at all.

We should also observe that you will search Sober in vain for any indictment of deep inconsistencies on Gould's part. Sober is not faulting Gould's consistency, he is faulting his logic (rather unfairly, as I have argued). Sober was not discussing the proper relationship between science and theology, but rather the strength of certain versions of the design argument.

As for NOMA, Gould's point was that theologians should not make pronouncements about natural history becuase they have no evidential basis for doing so. Meanwhile, scientists should not turn their theories about and observations of nature into worldviews or systems of morality, because the facts of nature tell us nothing about proper behavior. Is that so complicated?

And the phrase “The panda's thumb argument amounts to a hopelessly contradictory methodology” is one of those masterpieces of nonsense only a creationist could write. There is no methodology under discussion here. And there is no contradiction either; what Nelson describes in his final sentence, if it were accurate, would amount to hypocrisy, not contradiction.

Gould's point was very simple and obviously correct. A certain class of observations we make about nature, exemplified by the panda's thumb, are easy to explain as the products of evolution but hard to explain as the products of an omnipotent, omnibenevolent designer. That's it. Only overzealous philosophers or creationist leeches could find something to argue with here.

Nelson has had this pointed out to him before. Here's Robert Pennock, in his book Tower of Babel

However, Nelson's argument improperly conflates the positive argument for evolution with Gould's negative argument against creationism. Nelson's confusion is not surprising given that on the dual model view creationists presuppose that rejecting the one is equivalent to proving the other. If Gould's comment about what a sensible God would never do were meant to be taken as part of a scientific argument, then Gould has indeed improerly violated methodological naturalism in his negative argument, for science has no way to test what would or would not be sensible from God's point of view. But ruling out this argument does not affect the positive argument. The reason that odd arrangements and makeshift adaptations are evidence of evolution is that these constitute a kind of pattern that is an expected effect of evolutionary processes, which must work at any given moment within the constraints imposed by previous evolutionary development.

At the end of the day the situation is very simple. ID proponents, almost without exception, believe in the Christian idea of an all-powerful, all-loving God. It is for them to explain why such a God afflicts his creations with such obvious examples of poor design. So far they have been completely unable to do so. The few suggestions they have made are laughably inadequate. But that is a subject for another post.


At 1:04 PM, Anonymous Anonymous said...

This is a great site.

The ID argument is so thin....and they mis-quote so would think they are Delay republicans!!

At 7:20 PM, Blogger Jason said...

Thank you for the kind words. I'm glad you like the blog.

At 9:24 PM, Blogger stopitplease said...

I think you’re being overly critical of Sober due to Nelson’s hijacking of Sober’s points – an all too often employed tactic of ID/creationists as you know. Sober is simply making a philosophical (logical) observation here, one that certainly doesn’t suggest any truly divine involvement (or the lack thereof) in the evolutionary process. For Sober, and virtually all philosophers of science, “God” represents a conceptual construct and is not to be taken literally. Gould is doing the same thing but making a scientific point and not concerned with the conceptual precision that Sober is. It is, as you suggest, an overzealousness on Sober’s part but that’s what philosophers do.

At 2:28 PM, Blogger Jason said...

I'm actually a big fan of Elliott Sober, despite my disagreement with him here. I've read quite a few of his books and papers and have always found them interesting and insightful.

It was that line about Gould being ensnared in a trap that bothered me, as well as the implication that Gould had overlooked the assumptions he was making about God's character in ihs Panda's Thumb essay. I don't think those criticisms are valid.

At 11:43 AM, Blogger stopitplease said...

Yeah, I can see that. Comparing Gould with Paley is a bit over the top.


Post a Comment

<< Home