On August 14, William Dembski spoke at the Computations in Science Seminar at the University of Chicago. Was this a sign that Dembski’s arguments for intelligent design were being taken seriously by computational scientists? Did he present new evidence? There was no new evidence, and the invitation seems to have come from Dembski’s Ph.D. advisor Leo Kadanoff. I wasn’t present, and you probably weren’t either, but fortunately we can all view the seminar, as a video of it has been posted here on Youtube.
It turns out that Dembski’s current argument is based on two of his previous papers with Robert Marks (available here and here) so the arguments are not new. They involve considering a simple model of evolution in which we have all possible genotypes, each of which has a fitness. It’s a simple model of evolution moving uphill on a fitness surface. Dembski and Marks argue that substantial evolutionary progress can only be made if the fitness surface is smooth enough, and that setting up a smooth enough fitness surface requires a Designer.
Briefly, here’s why I find their argument unconvincing:
- They conside all possible ways that the set of fitnesses can be assigned to the set of genotypes. Almost all of these look like random assigments of fitnesses to genotypes.
- Given that there is a random association of genotypes and fitnesses, Dembski is right to assert that it is very hard to make much progress in evolution. The fitness surface is a “white noise” surface that has a vast number of very sharp peaks. Evolution will make progress only until it climbs the nearest peak, and then it will stall. But …
- That is a very bad model for real biology, because in that case one mutation is as bad for you as changing all sites in your genome at the same time!
- Also, in such a model all parts of the genome interact extremely strongly, much more than they do in real organisms.
- Dembski and Marks acknowledge that if the fitness surface is smoother than that, progress can be made.
- They then argue that choosing a smooth enough fitness surface out of all possible ways of associating the fitnesses with the genotypes requires a Designer.
- But I argue that the ordinary laws of physics actually imply a surface a lot smoother than a random map of sequences to fitnesses. In particular if gene expression is separated in time and space, the genes are much less likely to interact strongly, and the fitness surface will be much smoother than the “white noise” surface.
- Dembski and Marks implicitly acknowledge, though perhaps just for the sake of argument, that natural selection can create adaptation. Their argument does not require design to occur once the fitness surface is chosen. It is thus a Theistic Evolution argument rather than one that argues for Design Intervention.
That’s a lot of argument to bite off in one chew. Let’s go into more detail below the fold …