Derb, I can’t help thinking that you’re confusing two quite different concepts. To wit:
Concept One: The reification of reason—that is, the belief that reason is Reason, something with an objective and valid existence outside ourselves. The philosophical debate over Reason gets to be heavy going in a hurry, but it’s worth noting that we all behave as if reason did indeed possess an existence or truth of its own: Two plus two, we all understand, equaled four long before the first hominid mind came into being.
Concept Two: Reasoning ability—that is, the ability of the brain to add, subtract, tell truth from falsehood, and so on.
Concept One represents reason in itself, Concept Two the ability to work with reason. And whereas it’s perfectly true that reasoning ability may have evolved—in your neat phrase, “If natural selection could come up with legs, fins, eyes, and guts, it’s hard to see why it shouldn’t come up with advanced intellectual faculties”—it would have proven impossible for reason itself to have evolved.
Which brings us to Wieseltier: His review of Dennett’s book wasn’t the attack on evolution that you seem to have supposed. It was an attack instead on materialism—on Dennett’s implicit assertion that nothing exists but the world we perceive by way of our five senses. Hence Wieseltier’s question—”if reason is a product of natural selection, then how much confidence can we have in a rational discussion”—isn’t “vacuous,” to use your word, but absolutely basic. If “reason” is simply a physical property, then logic and truth possess no greater claim upon us than, say, the preference for red wine over white, or Bach over Wagner. Thought processes would be mere chemical reactions. Why should anyone prefer the chemical reactions of Daniel Dennett to those of John Derbyshire? Intellectual life instead utterly depends upon the opposite notion, the notion that our reasoning faculties are capable of apprehending objective truth—in a word, Reason. And if there is indeed such a thing as Reason, well, then, there’s more to the universe than the sheerly material world.
C. S. Lewis puts this all much better than I can—and I like the quotation I used yesterday so much that I may as well repeat it:
“Granted that Reason is prior to matter [as it is in the traditional Judeo-Christian conception of the word], I can understand how men should come, by observation and inference, to know a lot about the universe they live in. If, on the other hand…minds are wholly dependent on brains, and brains on biochemistry, and biochemistry…on the meaningless flux of the atoms, I cannot understand how the thought of those minds should have any more significance than the sound of the wind in the trees.”