The problem with “Intelligent Design”

There were more political stories to get outraged about today, but I’m preaching to the choir on those (except for Anonymous Crab maybe) so we move to Science and Religion where I know there is going to be some interesting discussion.

I just read this book about Evolution. The author, who won this year’s Templeton prize, summarizes the case for Evolution pretty conclusively, and in the last chapter talks about how one can believe in both Evolution and God, they are compatible. He starts with the well-known point that although Evolution contradicts literal readings of the Bible and is therefore inconsistent with the beliefs of certain subgroups of Christians, one can view Evolution as God’s way of bringing about life, and, ultimately, us.

More usefully, he goes on to show that Evolution actually makes it easier to believe in God by disarming two arguments against God’s existence. The first of these is the crude argument that many living systems are (in MIT parlance) “hacks”, jury-rigged botched Rube-Goldberg devices that could obviously be designed much better; therefore God could not have designed them. This is a crude argument because it is not essential to the concept of God that everything in the world he created conform to the best practices of the human engineering profession. Nonetheless, Evolution explains how the systems could have arisen without a Designer and so saves God from the charge of incompetence (I’ll deal below with more serious issues related to Design). The second, more serious argument against God that Evolution addresses is the problem of Natural Evil — “the dysfunctions and cruelties of the living world”. Natural evils in the biological sphere — parasites that kill millions of people, a poorly designed human reproductive system that results in large numbers of miscarriages and a birth process dangerous to both mother and child — arose by natural evolutionary processes which don’t entail moral values, so God is not to be blamed for creating them.

This is OK as far as it goes, but the book disappointed me because it failed to engage the more serious issues related to the Design question. In particular, it would be nice to directly tackle the question of God’s existence or non-existence, rather than the meta-issue of whether belief in God is compatible with a scientific theory (because “compatible with” doesn’t say whether it is true or false).

It is helpful to recall what all the fuss was about when Darwin first published his theory. Why did people feel that it threatened, not only Bible-is-literally-true fundamentalism, which the sophisticated divines of the Church of England had, along with Catholics, long since rejected, but also the very existence of God?

They felt this because of a common logical error. What Darwin’s theory seemed to destroy was one particular argument for the existence of God, namely the “Argument from Design”. However, just because an argument is invalid doesn’t mean the conclusion is false! If the Argument from Design were the only argument for God’s existence that had ever been taken seriously, then Darwin’s theory ought to have been a heavy blow, but of course theologians have had many other arguments for God’s existence (which I will discuss in other posts if the response to this one is interesting). I think that the Argument from Design is the only argument that many people understood, and the (Anglican) establishment’s opposition to Darwin stemmed from a fear that the ignorant people in the pews could not be persuaded of God’s existence by any other argument.

So only fundamentalists should ever have felt threatened by Darwinian evolution. However, the Argument from Design wasn’t completely killed by Darwinism after all. It survives today in two forms: the physicist’s observation that the fundamental laws of the Universe appear to be suspiciously fine-tuned to produce life, and us; and the biologist’s observation that Darwinian evolution as currently understood appears insufficient to explain much of the life’s complexity and diversity.

The physical version of the AfD is not really serious yet, because we don’t actually know the fundamental laws of the Universe yet, and furthermore there are “anthropic” considerations which might explain the apparent fine-tuning, once we know more.

But the biological version of the AfD is serious and scientifically reasonable. Evolution has limitations that we know about; it must proceed by small changes in genomes which arise as random (to some degree) mutations, and each stage must itself be viable as an organism. A complex system that could not have arisen by a gradual sequence of systems each of which was itself viable cannot be formed by the normal evolutionary process, though God or Craig Venter could do it.

The “Intelligent Design” movement uses arguments from systems theory and probability theory and attempts to show that certain biological systems are so unlikely to have arisen through natural selection that the alternative hypothesis of God (or some extraterrestrial Craig Venter) is worth considering. The best and most representative research has been done by IDers Michael Behe (in his work on “irreducible complexity”) and William Dembski (in his work on the origin of the genetic code). I won’t deal with Dembski here since there is a lot of recent technical work in the field which I’m not very familiar with (though on the whole it supports the idea that the code could have arisen gradually, it does not appear to be at all conclusive).

But I would like to talk about “Irreducible Complexity”. Behe uses systems like the bacterial flagellum, or the blood-clotting cascade, as examples of irreducible complexity, defined as a system which cannot function if any one of its parts is significantly altered or removed. Details are in his book.

Most of the criticism of Behe, by people like Richard Dawkins and Kenneth Miller, has missed the real problem. The critics have tried to argue that the systems Behe describes are not really irreducibly complex after all, and they have made unconvincing and sketchy attempts to construct parts of a hypothetical evolutionary path leading up to the bacterial flagellum or the blood clotting cascade. However, even if they did this, they would only be refuting particular examples of Behe’s argument, and he could find plenty of others. Their criticism amounts to a statement of faith that gradual sequences building up to the “irreducibly complex” systems will be found, and to a concession that true irreducible complexity would indeed be unachievable by Darwinian evolution.

However, there is a much more fundamental problem. What has been overlooked is that evolution can cut down as well as build up (and in fact it is much more likely to do so, since it is much easier for a random mutation to break a gene than to turn it into something better). IDers (at least the ones who are real scientists) concede that evolution by Darwinian selection occurs, they just say that it is insufficient to generate the full complexity and diversity we see (the theological subtext is that God or Craig intervened in the process and guided it at some point). This means they admit that evolution CAN build complex systems in a gradual way.

But suppose you have a complex system that has been built up gradually, performing some kind of useful function at each step, and all jury-rigged and Rube Goldbergish like such systems are often observed to be.

What will happen next?

Mutations that kill inessential parts of a redundant system might actually be beneficial, the reduced system might get the task accomplished while using less energy for example. So one would expect evolution once operating on an already working system to streamline it. When does this stop? Obviously, when it can’t go on any more. At some point every additional change will destroy the system’s function — so the system will not change any further. It is irreducibly complex, and this has ARISEN NATURALLY.

One should EXPECT irreducibly complex systems in biology, all over the place. The only reason this was overlooked is that everyone imagined complex systems as having grown ever more complex over time, as if the only possible change was in the direction of greater complexity. I don’t see how the concept of “irreducible complexity” retains any power to refute evolution once this is taken into account.

What does this mean theologically? Only that the Argument from Design remains in the discard bin. That doesn’t refute God, just one argument for God. And it is still conceivable that somewhere in our “junk DNA”, someday, the A’s T’s, G’s, and C’s in a certain segment will be revealed, using some reasonable error-correcting code, to say “Made by YHWH” or “Craig was here”. That would be a funny joke on the evolutionists, and it can’t be ruled out; but although the bioinformaticists currently working with the DNA databases will probably eventually discover such a thing if it is there, I don’t think it’s either scientifically or theologically important to look for it.


About Polymath

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One Response to The problem with “Intelligent Design”

  1. I see I’ve been too reasonable and obviously right again, no one is commenting. Does anyone want to use any points made in the discussion here to argue either for, or against, the existence of God?

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