Bob Murphy, always my favorite theist, posts a defense of Intelligent Design theory, or at least an attack on its attackers, who, he claims, have largely failed to grasp what the ID theorists, such as Michael Behe, are claiming:
Behe is fine with the proposition that if we had a camera and a time machine, we could go observe the first cell on earth as it reproduced and yielded offspring. There would be nothing magical in these operations; they would obey the laws of physics, chemistry, and biology. The cells would further divide and so on, and then over billions of years there would be mutations and the environment would favor some of the mutants over their kin, such that natural selection over time would yield the bacterial flagellum and the human nervous system.
Yet Behe’s point is that when you look at what this process spits out at the end, you can’t deny that a guiding intelligence must be involved somehow.
Perhaps Bob has forgotten that I disposed of this argument in Chapter 4 of The Big Questions , with a single counterexample that refutes both Behe and his polar opposite Richard Dawkins in one fell swoop. Let’s recall their positions, stated as simply as possible:
Behe: Irreducible complexity requires an intelligent designer.
Dawkins: Irreducible complexity requires evolution. (This is Dawkins’s stated position in his book The God Delusion.)
Landsburg: The natural numbers are irreducibly complex, moreso (by any reasonable definition) than anything in biology. But the natural numbers were not designed and did not evolve, so Behe and Dawkins are both wrong.
This is usually the point when someone with all the sophistication of a sophomore jumps in to object that the natural numbers are not “real”; they are merely figments of our imagination or some such thing. To which I reply: Hey, maybe you’re just a figment of my imagination. Maybe I’m the only sentient being in the Universe, and I’ve just imagined up all these flagella, cells, and organisms, and that’s the sum total of everything you need to know about biology. Also, there’s no need ever to debate the causes of the Civil War because that might have been imaginary too. The point here is that you can always shut down any discussion about anything by retreating to a position of extreme skepticism, but that’s never been a good way to make intellectual progress.
(And no, that’s not an argument for admitting the reality of unicorns and flying spaghetti monsters. If you need convincing that the natural numbers — unlike unicorns — are at least as likely as your furniture to exist outside your mind, then do buy yourself a copy of The Big Questions today!).
And if you doubt the complexity of the natural numbers, then you are probably unaware of the vast mathematical literature on how unfathomably complex the natural numbers (provably) are. For starters, the set of true statements about the natural numbers is too complex (in a very precise sense) to be derived from any system of axioms. The set of true statements about your brain, by contrast, is probably easy in principle to axiomatize (though to make this precise, you’d have to be precise about what sort of statements you’re allowing).
So what responses might we expect from Behe or Dawkins? Behe, I think, would have the easier time of it, since he can always contend that the natural numbers must have been intelligently designed. But that paints him into a pretty isolated corner. In my experience, even the most committed theists are reluctant to believe that an equation like “2 plus 2 equals 4″ is the result of a design choice.
For Dawkins, I think, the game is up. Surely he won’t want to argue that the natural numbers have evolved, so that their properties today are different from their properties at some time in the distant past. (Of course, our knowledge of the natural numbers has evolved, but that’s a different matter entirely.)
Not everything that’s complex — not even everything that’s irreducibly complex — was designed. Not everything that’s complex evolved from something simpler. Whether any given complex structure was designed, or evolved, or was just plain complex from the get-go, is a question that requires more than an appeal to glib, and demonstrably false, generalities.