Monday, March 15, 2010

Blinded by the algorithm

This post is a bit lame, as I have not yet been able to locate a copy of Richard Dawkins' "Blind Watchmaker."

I've been reading Francis Crick's autobiographical "This Mad Pursuit," written when he was about 70. He was very enthusiastic for Dawkins' argument against intelligent design, which he summarized thus:

The probability of obtaining a single string of binary digits is extraordinarily remote for even 40 digits (2^40). However, the probability of obtaining a string through "cumulative probability" is quite high. Dawkins had a program select a random digit string and then match it  against a template string. By a series of approximations the template was matched after some 40 steps.  This is really a variation of the game of Twenty Questions.

Crick, who trained as a physicist, doesn't seem to have noticed the difference in issues here. If one is talking about the origin of life, we must go with the 2^40 analogy. If one is talking about some evolutionary algorithm, then we can be convinced that complex results can occur with application of simple iterative rules.

(Interestingl;y, one study has recently determined that speciation events are not normally distributed, but appear to be exponentially distributed, like radioactivity half lives.)

One can only suppose that Crick, so anxious to uphold his lifelong vision of atheism, leaped on Dawkins' argument without sufficicient criticality. On the other hand, one must accept that his analytic powers may have been waning.