The Failures of Mathematical Anti-Evolutionism
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The Failures of Mathematical Anti-Evolutionism (Jason Rosenhouse) (z-lib.org)
(Dembski 2002, 210)
6.8 the no free lunch theorems 203 In a later paper coauthored with Robert J. Marks II, Dembski was even more explicit about the intent of his argument: We are not here challenging common descent, the claim that all organisms trace their lineage to a universal common ancestor. Nor are we challenging evolutionary gradualism, that organisms have evolved gradually over time. Nor are we even challenging that natural selection may be the principal mechanism by which organisms have evolved. Rather, we are challenging the claim that evolution can create information from scratch where previously it did not exist. The conclusion we are after is that natural selection, even if it is the mechanism by which organisms evolved, achieves its successes by incorporating and using existing information. (Dembski and Marks 2011, 389) When Dembski first presented his argument in his 2002 book, many commentators took him to be saying that the NFL theorems in some way imply that evolution cannot construct complex adapta- tions. It is understandable that they thought so. These theorems were the centerpiece of a book arguing against evolution, and Dembski did, after all, write things like, “The No Free Lunch theorems dash any hope of generating specified complexity via evolutionary algorithms.” The last two quotes make clear that Dembski, and later Dem- bski and Marks, are really just saying that evolutionary mechanisms achieve such success as they do only because they manipulate infor- mation from the environment. In effect, they are saying, “Biologists thought that evolution was able to create eyes, wings, and immune systems from scratch, thereby producing complex, specified informa- tion where no such information existed before. In reality, evolution just manipulated previously existing complex, specified information into a new form, and you still have to explain the origin of that prior information.” Understood in this way, this is a very strange argument. Most of us did not need difficult mathematical theorems to realize that Dar- winian evolution is viable only when nature has certain attributes, 204 6 information and combinatorial search and it is not a defect in evolutionary theory that it takes these attributes for granted. It is trivial to imagine alternate realities very much like the one we are in, but in which Darwinian evolution would never have gotten anywhere. The fitness landscapes confronted by evolving organisms arise ultimately from the laws of physics, and therefore the ID argument is tantamount to wondering why those laws are as they are. But determining why the universe has just the properties it does is hardly a problem within biology’s domain. As we suggested in Section 6.3, there is nothing wrong with viewing natural selection as an information conduit between the environment and a population’s gene pool. Recall that according to Shannon’s conception, information content is something possessed by an event in a probability space. Seen in that way, any physical system that can exist in more than one state can contain information. This is because if the system can exist in more than one state, then there must, in principle, be a probability distribution that describes the likelihood of being in one state versus another. And since the local environments in which gene pools find themselves can certainly exist in many states, it is not an abuse of language to say the environment contains information. This can actually be an illuminating metaphor. There is a strong sense in which the gene pools of modern organisms can be said to record information about the ancestral environments in which they evolved. The process is not much different from receiving medical information from your doctor and then making lifestyle changes as a result. Just as your doctor gives you information on how to live a healthier life, so too does the environment give information to a gene pool about how better to survive. In the language of information theory, we would say this is communication through a noisy channel because natural selection is not the only mechanism of change, and evolution is not always adaptive. But it is an interesting way of looking at things nevertheless. Biologists frequently make statements to the effect that evolu- tion can create information. For example, in his 1961 paper referred to in Section 6.3, Motoo Kimura writes: 6.8 the no free lunch theorems 205 We know that the organisms have evolved and through that process complicated organisms have descended from much simpler ones. This means that new genetic information was accumulated in the process of adaptive evolution, determined by natural selection acting on random mutations. Consequently, natural selection is a mechanism by which new genetic information can be created. Indeed, this is the only mechanism known in natural science which can create it. Download 0.99 Mb. Do'stlaringiz bilan baham: |
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