The fact that something is natural doesn't make it good. To say that something's natural is simply to say that it accords with the way we happen to be as a result of evolution.It depends what you mean by natural. I'm not sure that anyone has ever really explained what 'natural' means, but it certainly does not always mean what Buchanan says it means. Anscombe, as I recall, says that in Catholic thinking (or perhaps in Aquinas) 'natural' sometimes just means good or not wrong. But I think some people use it to mean a sort of cross between the positive (or Humean) conception Buchanan has in mind and the purely normative sense that Anscombe describes. There is a sense I find in people such as Leon Kass and Michael Sandel that the source of life, call it God-or-nature, is good. Jonathan Haidt describes people trying to justify moral reactions by imagining the harm that could come from this or that odd situation (incest where pregnancy is impossible, a man having sex with a frozen chicken, etc.). Basically, when we disapprove of something we will (often) claim that we do so because we foresee bad consequences. Pointing out that such consequences are highly unlikely shows not so much that we are wrong to disapprove but that we disapprove for some other reason.
In these cases we need to dig a bit, or just think more. Ronald Dworkin does this kind of reconstructive moral psychology in Life's Dominion (I think he does a good job, others disagree), as does Jonathan Haidt in his most recent work (not well in my opinion, but others no doubt differ). In Better Than Human Buchanan unhelpfully politicizes the issue of biological enhancement, mentioning George W. Bush as often as possible (so that conservative moral positions are associated with conservative political positions) and even bringing in Patrick Devlin (think nature is a seamless web? well you know who else talked about seamless webs...). The issue is already controversial enough without bringing in guilt by association. Other than this Buchanan's arguments are good (so far--I'm only halfway through the book), but he seems blind to the possibility that respect for nature and/or life might be a value. He points out that nature isn't always nice, even quoting the old "red in tooth and claw" line and committing what I think of as the Black Corridor fallacy, namely treating the amorality of something impersonal as if it were a kind of cruelty. Jonathan Balcombe combats this attitude with a chapter in Second Nature about the warm and fuzzy side of nature. But I think this is not enough.
How can one possibly live as if nature were an enemy to be struggled against? That seems so wrongheaded to me that even neutrality seems close to impossible. Something like Chesterton's primal loyalty, along with his hating the world enough to change it and loving it enough to want to change it, seems not only good but practically necessary to me. How can we live sanely without thinking of the natural world, or just the universe, as our home? And how can we (again: sanely) avoid warm feelings about home? Buchanan shows no loyalty to nature, happily suggesting that we re-engineer mice, for instance:
the post-mouse future will arrive considerably ahead of the post-human future, and that's a good thing. Let them be the risk-pioneers. (p. 94)The post-mouse future referred to is one in which mice have been so changed as to no longer be what we know as mice. How is this good? Buchanan writes in this passage as if it's good for us, because the risks involved will fall on the mice. To be fair to him, though, we should consider that he might also mean that it's good for the mice, because they will become post-mouse by being enhanced, not just changed but improved. This raises the question what constitutes improvement. A better mouse-trap does its job better, but mice don't have a job (unless they were built for a purpose by the Creator, in which case Buchanan is wrong). Better mice might be happier mice, but we ought not simply to assume that happiness is the only relevant value. Or we might think of mice in more or less Aristotelian terms, as having not so much a job but a function, or multiple functions. There are things mice do: see, hear, run, avoid cats, etc. If we make them better at some or all of these things then they will be better mice. Perhaps. But there's also the idea that mice are something like works of art. And then improving them no longer makes much sense as an idea, except in cases where sick or handicapped mice are made more like standard mice.
The cosmic patriot or jingo of the universe, as Chesterton puts it, would love mice just as they are, and would want no part in trying to enhance them. The very idea of improving mice would be like the idea of improving Hamlet (perhaps by adding a sex scene). The same, only more so, would go for human beings. You can't really think (can you?) both what a piece of work is man and we can make him better. Not without a dismissive "yeah, yeah, I get it" after the 'what a piece of work' part anyway. And it's resistance to the "yeah, yeah" attitude that I think Buchanan doesn't get. Otherwise, as I say, I think I agree with him. But I haven't finished the book yet, and I worry that there might be a kind of no true Scotsman problem lurking for someone who takes my position. For now, though, I must stop blogging and enhance my back garden by weeding it before it gets too hot.