My friend Chad at CCK has this comment:
Robbinsdale Radical reminds us that John Thune doesn't believe in evolution.
I went to robbinsdale radical and found the post that Chad has in mind, but the only evidence of John Thune's opinion on evolution that I found was a link to one of my own posts in which I explicitly confirm my own belief in evolution. I don't happen to know what Senator Thune thinks about evolution, and I am guessing that RR and CCK don't know either.
But RR and CCK put us on to an interesting argument. Here is the Radical's take:
One of the arguments against evolutionary theory is that complex parts that work together could not have developed independently and certainly not placed in their complex structure without divine intervention. It's a very tempting argument, especially if you are inclined to the geological time scale and are amazed (you should be) at structure like the human eye and also in the marvelous interdependence of entire ecosystems.
You may have heard this as the "wristwatch on the beach" argument. It's a very old and weak line of reasoning that dates back before Christianity, and was a popular criticism of Darwin in the 19th century.
In fact, I think that RR has misidentified the "irreducible complexity" argument. It is not an example of the argument from design (designed things like the human eye imply a designer), but of the argument from causation. See St. Thomas Aquinas Five Ways, numbers 2 and 5. Here is an example of the latter:
1) The only natural way to get a chicken is from a chicken egg;
2) The only natural way to get a chicken egg is from a chicken;
3) There was a time in the past when there were no chickens.
4) Therefore: chickens can only have come into being through some supernatural force.
That looks like a valid argument to me, in so far as the conclusion 4 follows from premises 1-3. Of course Darwinian theory decisively undermines premise 1: you can get chickens by natural speciation from some proto-chicken species.
Intelligent Design Theory attempts to repair the argument by showing that Darwinian mechanics is insufficient. The latter can explain the evolution of complex organic structures from simple ones only if the structure confers some reproductive advantage at every stage of its history. But some organic structures (the current favorites are complex molecular devices) function only if they are complete and not at all in simpler, partial versions. Hence they are irreducibly complex. So you still need chickens to get chicken eggs.
That is not a stupid argument. It is very sophisticated biologically and philosophically, which is evident from the fact that its failure illuminates and strengthens Darwinian theory. RR and CCK direct us to an excellent blog post by Sharon Begley that shows why the argument fails.
[The irreducible-complexity crowd] makes a fatal error: they assume that whatever the function of a biological component (gene, protein, biochemical pathway . . . ) today must have been its function in the past. Maybe you noticed that my mouse trap example above wasn’t very persuasive; even without a base and a bar, a spring can be a useful little device. So it goes with biological systems. For instance, of the 42 proteins known to make up the bacterial flagellum, 40 have been found to serve as ion channels or something else in bacteria. It is therefore perfectly plausible that they really were hanging around—serving some function that would have allowed evolution and natural selection to keep them around generation after generation—until they all got together and formed a flagellum.
This seems to me to be dead spot on. The flagellum, basically a fin that bacteria use to swim, has been used as an example of irreducible complexity. It is in fact the result of simpler machinery turned to new uses by natural selection. Ms. Begley focuses on a study that found genes for producing synapses (the cellular structures allow that our brain cells to form a network) in sponges, which presumably have no brains.
Evolutionary theory wins every one of these many battles. That is why I believe in it. But it is made stronger by the argument, and that is why Darwinism benefits from an honorable opposition. I differ from the Robbinsdale Radical and the Clean Cut Kid only in this: I think that evolution is a way to explore and understand the wonders of the world, and not just a weapon with which to belittle persons of faith.
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