Tuesday, August 05, 2008

Evolution is winning

This is encouraging. The premier Creationist web site seems to be surrendering on nearly every front. The only argument that AIG doesn't seem to concede (yet) is the so-called information "problem", which flames are being fanned by the infamous -- but just as fictitious as the rest of Creationism -- stumping of Richard Dawkins.

This is good, because the information-theoretic objection to evolution is very easily dispensed with. The objection, due originally to Dembski (a name just begging to be parodied, but I will resist) is that because evolution is a random process it cannot add information to the genome. Therefore, all the information currently contained in all the genomes of all the living things on earth must have been present at creation.

There are three things wrong with this argument.

First is the common straw-man that Creationists keep setting up (well, when you're arguing an untenable position what else can you do?): evolution is NOT random. *Mutation* is random. But evolution is mutation PLUS NATURAL SELECTION, and natural selection is most decidedly NOT random.

This alone is enough to completely demolish the evolution-can't-add-information argument (and 99% of the other creationist objections to evolution by the way). It can, and it does. The mechanism it uses to do so is (non-random) natural selection for reproductive fitness. But there are two other problems with the proposition that evolution cannot produce information that are worth mentioning. So...

Second, it is not the case the evolution *necessarily* produces an increase in information. It just turns out that way most of the time (with a caveat -- see the final point below). Sometimes evolutionary processes create information, and sometimes they destroy information. It just turns out that the trend is generally towards bigger and more complex genomes. But it isn't *necessarily* that way, any more than technology *necessarily* develops by getting more complicated. It's possible for evolution to proceed by simplification just as it's possible for technology to proceed the same way. It just rarely happens. And the reason is the same in both cases: complexity begets complexity because complex things tend to reproduce better in an environment already populated by other complex things.

Finally, it is far from clear that the premise of the creationist's argument is even true because it is at all clear how much of the DATA contained in the genome is actually INFORMATION. Data and information are not the same thing. All genomes contain large amounts of junk DNA that doesn't serve any apparent purpose as far as we know. In the context of such a large amount of essentially random data it is not at all clear how much actual information is contained in the non-junk areas of the genome, and how much of the information content is actually contained in the environment (i.e. the ribosome, and the chemical interactions of proteins). A complete discussion of this would take more time than I have right now. Might make an interesting topic for another post.

No comments: