Oh, no--not more discussion of higher purpose! Well, OK. Having failed to turn our dialogue into a more proportional promotional vehicle for my book (you know--gripping historical narrative, etc.), I'll wrestle some more with thermostats and God, then get back briefly to the subject of history.
You write, "But natural selection itself, being a product not of a teleological process but of the physics and mathematics of replicating systems, has no right to have a goal in the way that genes or people or thermostats do." Here your argument seems to be that there's some contradiction between being teleological and being physical and mathematical. But I don't see any such contradiction. A system can be entirely mechanical, complying with the laws of physics and mathematics, yet be teleological, designed to realize a purpose. In fact, that seems to be true of all teleological systems I know of, including genes and people and thermostats.
I agree with you that, so far as we know, purposeful systems must arise by design, "either from conscious intentionality or from selection." So, if natural selection is purposeful, it presumably was set in motion either by some intelligent being or by a process of meta-natural-selection (of the type that, I note in my book, is suggested by Francis Crick's semi-wacky but intellectually useful "directed panspermia" scenario). You dismiss the latter possibility by saying: "Since natural selection was not naturally selected (or if it was, we'd ask the same question of the meta-selection process) ..." But I don't follow your logic. Granted, there is always the problem of the infinite regress--whenever you assert a designer of anything, someone can say, "Well then what designed the designer?" But your inability to answer that question doesn't mean your initial assertion was wrong.
At the risk of caricaturing your position, let's imagine a conversation between two (unusually articulate) cells in a developing organism. They see the proliferation of their various fellow cells but can't see outside the organism they constitute. The Bob cell says, "Hey, how do we know there's not some larger purpose that this whole body full of cells is designed to achieve?" The Steve cell says, "Nah. Couldn't be. All that's going on is a process of the physics and mathematics of cell replication." Bob cell: "But what if this whole body of cells is the product of a process of design called natural selection?" Steve cell: "No, because if it were, then we'd just ask how that process of natural selection itself got selected. The buck has to stop somewhere."
I'm trying to make two points. One is that, from our puny perspective--as organisms designed mainly to get food, sex, status, friends, and so on, not to apprehend deep truths--we should maintain a healthy humility about large questions.
The other point is one that, fortunately, I won't have to defend in detail, but that I've pondered enough to at least throw out as a conjecture: It is much harder than you might think to make a clear, simple analytical distinction between a developing organism and the developing biosphere. (Obviously, there's one distinction: We know that the organism is a product of design, because we know about natural selection. But if you didn't have the zoological and fossil evidence to support a belief in natural selection--if you could inspect only one unfolding organism and one unfolding biosphere, with no knowledge about where either came from--I submit that you'd have trouble drawing a hard and fast distinction. From a distance, an unfolding biosphere looks pretty orderly, and from the inside, an unfolding organism would look pretty hurly burly and contingent.)
You ask whether I am "comfortable with the possibility that the arguments in Nonzero will be extrapolated into arguments for the existence of an intelligent designer." Broadly speaking, yes, because I think there is a distinct chance that natural selection is a result of some sort of design. In fact, in the book I present evidence that--I contend, in a speculative spirit--suggests as much.
What would bother me is if the book were enlisted by Social Darwinists who contend that "survival of the fittest" is a moral good, so war and oppression are good, and so on. I've tried to guard against this by attacking the (often unstated) keystone of this brand of Social Darwinism: the assumption that God is both omnipotent and benign (hence nature, God's handiwork, is a reliable guide to moral values). As I stress in the book, any "God" that designed natural selection couldn't possibly be both omnipotent and benign. There's too much suffering inherent in natural selection. For that matter, there's too much suffering in human history--in the rapid cultural evolution that biological evolution gave birth to when it designed us.
At the same time, I do argue that there has been a kind of moral improvement through history. Ancient Athenians once considered non-Athenian Greeks subhuman. Then they decided that, actually, all Greeks are human, but those Persians should be treated "as though they were plants or animals," as Aristotle reportedly advised Alexander the Great. Today we at least pay lip service to the idea that all humans are human, worthy of decent treatment. I think this expanded moral compass resulted from the basic direction of human history--the expanding web of "non-zero-sumness," of interdependence (economic and otherwise).
This isn't to say that the future of humankind will be a global lovefest. There will always be zero-sum games, and accompanying tensions. What's more, non-zero-sum games, if misplayed, can yield lose-lose outcomes. If our species misplays these games--if nations fail to see that growing non-zero-sumness calls for growing cooperation--we could see catastrophes of various kinds. Still, I find this oddly heartening--that history's basic direction is leading us to greater levels of cooperation, even if it sometimes leads us there at gunpoint.
All told, I think there will be enough logic--economic, political, and other kinds--behind collaboration and cooperation so that the Internet will weave us together into something that does resemble, more and more, a global brain. The Jesuit paleontologist Pierre Teilhard de Chardin was a mystic who doesn't seem to have appreciated natural selection, but I do think he was onto something when he coined the term "noosphere" for the "thinking envelope of the Earth" and predicted (half a century ago) that it would thicken inexorably. (The phonetic parallel with "biosphere" was intentional.)
One final point, left over from your first posting: I grant you that our species' evolution of great intelligence hinged on a fortuitous conjunction of features (sociability, etc.). But the argument in my book isn't that our species was likely to luck into that conjunction--just that one species or another was, given enough time. (See chapters 19 and 20 for supporting evidence, or a more condensed version of the argument in my recent critique of Stephen Jay Gould, published in The New Yorker and now available at www.nonzero.org.)
Well, it's been fun. I wish all book reviews gave the author this luxury of talking back. And I wish all book reviewers were as acute as you. No, actually, come to think of it, maybe I don't.