OK, folks, I promise I'll stop soon, but before the year ends I need just one more evolution fix.
I don't have the Dawkins book I've been reading with me now, so I can't quote directly, but in it he recaps the argument he made in The Selfish Gene: humans are "really" just survival machines for genes, which discard us when we have served their "purpose." He even presents a little song he penned celebrating this fact for a conference.
Now, I've gotten a few letters on my recent columns to the effect, "Leave the biology to the experts." But my point has been that the biologists have not been leaving the philosophy to the experts, and, indeed, have often not even recognized when they have left the realm of biology and entered that of philosophy. One thing philosophers are trained to do is sort out bad arguments from good ones. So let's see which category Dawkins falls into.
The form of the argument is: X and Y are closely related entities. (E.g., a human and his genes.) But while Xs come and go, Y endures through this series of new relata. (E.g., the same gene can appear in generation after generation of people.) And, somehow, the existence of Y depends on X. Therefore, the purpose of X is to maintain the existence of Y.
So, let's try out that form with some other contents. Theaters and plays are closely connected. But while plays come and go, theaters endure through scores of different shows. Obviously, theaters need plays to stay open. Therefore, the purpose of plays is to support theaters!
No, wait, let me try another: Autos and trips by motorcar are closely connected. But one auto endures through many trips. And if there were no possibility of travel by car, there would be no autos. Therefore, the purpose of car travel is to maintain the existence of automobiles!
In short, the argument is rubbish. That Y lasts through a succession of Xs says nothing at all about any purposeful relationship between them.