Dear Steve,
First of all, thanks for your kind words about my book. Thanks also for your characteristically penetrating questions about it. I doubt I’ll be able to answer all of them satisfactorily without my reply getting undigestibly long (if then!), but I’ll tackle some and hope we get to the rest tomorrow or the next day.
In a way, I hate to get sidetracked by the dicey issue you’ve focused on–the question of whether there is some larger “goal” or “purpose” that biological evolution and cultural evolution (or human history) are “designed” to realize. The bulk of my book is earthier: the story of the human past–from primordial ooze to World Wide Web. In particular, I’ve tried to isolate the engine behind history’s movement from hunter-gatherer band to globalized society, and thus shed some light on our technological and political future.
Still, I guess when you subtitle a book “The Logic of Human Destiny,” you can’t duck the cosmic questions. And you’re right that, in the book’s final two chapters, I address the question of higher purpose and suggest some answers, tentative and speculative though they may be. So here goes.
First, if I correctly understand your claim that “natural selection has the goal of enhancing replication, period,” then I take issue with it. To be sure, that is the fundamental goal natural selection instills in the things it “designs” (e.g., us), along with subordinate goals (eating, having sex, showing off in order to have sex, etc.). But whether natural selection, and the process of biological evolution it sponsors, are themselves in the service of a larger goal seems to me an open question. Certainly, as a matter of historical fact, biological evolution has accomplished things other than, and in a certain sense larger than, genetic transmission: It has created a whole biosphere; it has tended to raise the outer envelope of organic complexity and even of intelligence. It seems to me at least possible that these represent some larger “goal” that natural selection was “designed” to achieve. Maybe the basic goal of organisms–genetic proliferation–is subordinate to that larger goal, rather as the reproduction of cells within humans during their maturation is subordinate to the reproduction of humans upon their maturation.
I emphatically agree with you that “one attributes a goal to an entity only if it has a feedback mechanism that makes the entity approach the goal despite obstacles or perturbations.” In my book’s penultimate chapter, I use that very litmus test to address this question: If an extraterrestrial scientist could view the several billion years of life on Earth from some distance, and in time lapse, would he/she have valid grounds for postulating a “goal”?
For starters, the “goal” most evident to that alien would probably be growth in complexity–a more and more complex ecosystem, featuring, among other things, more complex organisms. But could the alien claim that the “goal” was approached by a “feedback mechanism” that adjusts to “obstacles and perturbations”? Yes, I think so. Natural selection, viewed from a sufficient distance, amounts to a giant information-processing system; via the selective replication of genetic information, it realizes both positive and negative feedback, thus adjusting species to environmental perturbations, and thus sustaining the growth of overall complexity even after encountering such obstacles as mass extinctions.
I like your question about human intelligence and elephant trunks (especially as you put it in How The Mind Works: “Imagine an astronomer on the Planet of the Elephants defending SETT, the Search for Extraterrestrial Trunks”). As you phrase the question in your posting–Was a human level of intelligence more likely to evolve than elephant trunks?–my resounding answer is: I’m not sure. But fortunately my book’s argument doesn’t hinge on the answer. I’m not saying the evolution of a human level of intelligence was any more likely than anything in particular–just that it was very, very likely given the amount of time evolution has to work on this planet before the sun checks out. (Here we seem to agree, though my arguments in the book go well beyond your observation that a human level of intelligence had “nonzero probability.” Still, I certainly approve of your using the word “nonzero.”)
Unless I’m overinterpreting, you have a second question about elephant trunks and human brains: Why should I focus on the latter if the two are equally likely to evolve? Here I can imagine several answers (e.g., human brains, unlike elephant trunks, are the seat of complex sentience–all the joys and agonies that make human life, I chauvinistically assert, uniquely interesting). But the main answer gets back to my book’s overarching thesis: that there is a kind of continuity and inexorability to the march from the primordial ooze to the World Wide Web. A human level of intelligence–unlike an elephant’s trunk–is a key step in this march, for it gives rise to a rapid and powerful kind of cultural evolution, an evolution that increasingly, in a sense, takes on a life of its own, and has gotten us from the stone age to now.
Speaking of now: The modern world, it seems to me, features a second kind of validation of my emphasis on the biological evolution of intelligence, and my insistence that biological and cultural evolution have important parallels. A number of observers have noted that the Internet (defined broadly, to include the people who communicate over it) strikingly resembles a giant global brain. No one has claimed that it resembles a giant elephant’s trunk.
In citing the Internet, I don’t think I’m just myopically focusing on the kind of technology that happens to be in vogue at the turn of this particular millennium. As I argue in Nonzero, ever since the Stone Age, technological evolution has tended to turn human societies into larger and more powerful information-processing systems, giant “social brains.” The Internet is just the latest example.
I really do think this helps justify my depicting human cultural evolution as a natural and in some ways continuous outgrowth of human biological evolution: Just as biological evolution, in inventing and developing multicellular life, took lots of dinky information processors (the genomes in individual cells) and subordinated them to a medium-size information processor (the human brain), cultural evolution has taken lots of medium-size information processors (human brains) and subordinated them to a larger information processor (an increasingly global human society).
OK, enough. I’ve tackled a couple of your points, and left some untackled. I hope to get to them all tomorrow or the next day, assuming you don’t keep coming up with new, equally challenging questions at your current rate. I’m especially intrigued by your final point, which gets into the moral/political/economic future of our planet. If you want to elaborate on your doubts about my guardedly optimistic view of the future of human cooperation, feel free. In any event, thanks for the questions. I hope I’ve done justice to at least some of them.
Best wishes,
Bob
