First, apologies if I am boring the hell out of everyone but a few of us fanatics with yet another sequel on naturalism and norms. It is just that I think the issues are very important, and I have gotten such terrific feedback on these points, that I am going to post a couple more replies to Philip K. and Dianelos.
Your commentary raises a good many deep issues, so many that pursuing them all would take us far afield and far exceed the space we have to address matters here. I think that the essential point that divides us is still the one about how we are to move from fact to value. How do we move from “doing well” in the sense of efficiency, as a mosquito is adapted to suck blood with efficiency, to a notion of “doing well” that has normative significance, indeed, that can serve as the summum bonum grounding our ethical norms. Let’s suppose that there are objective biological (encompassing psychological) criteria for the identification of the conditions that constitute human flourishing or well-being (eudaimonia). Suppose that that we discover that humans have distinctive and highly developed natural capacities that include a capacity for living a social life with other human beings and also include a capacity for rational behavior, behavior based not upon instinct or impulse, but upon a process of rational deliberation. Suppose further that, employing intuitive, non-tendentious notions of happiness, we observe that (given a modicum of physical and material well-being) the happiest people are those who most fully actualize their potentials for social and rational living. Since the moral and intellectual virtues are the habitual behaviors that are most conducive to actualizing those potentials, we note that the virtuous are the happiest. Conversely, those who do not interact successfully with others or who permit their rational faculties to decay will experience frustration, failure, loss, alienation, and meaninglessness.
OK, supposing all of this (and, of course, these suppositions might be challenged), we are still left with a seemingly glaring problem. As you state so trenchantly, just because humans are good at being rational, this does not entail that rationality is good. On what basis do we identify what humans are good at as being normatively good any more than what mosquitoes are good at? Yes, humans may experience happiness when doing what they are naturally good at, but why is this more morally significant than the sense of satisfaction a sentient mosquito would have at sucking your blood?
As compelling as many philosophers consider these questions to be, they rest upon assumptions that naturalists reject. Most fundamentally, naturalists reject the dichotomy between fact and value. It is a biological fact that certain states, conditions, and ways of living are valuable for human beings in that those things promote the physical, mental, and emotional well-being of humans, which well-being constitutes the ultimate, intrinsic value for humans. As the naturalist sees it, to admit this but then demand “OK, but why should we desire the physical, mental, and emotional well-being of humans?” is to ask a question that is pointless if not meaningless. What is the sense of this “should?” “Should” in the sense that every rational being qua rational is bound to respect it? But naturalists reject such categorical imperatives. “Should” in the sense that it is dictated by a moral imperative that rests upon something deeper and more valuable than human well-being? What could that be? The will of God, perhaps? But if God does not value our well-being (at least in the long run), on what grounds would we consider him good? This is why the doctrine of an eternal, punitive hell has always been such a stumbling block. A God who condemns much if not most of the human race to eternal torment is certainly not, prima face, a being worthy of being considered good.
There is indeed a sense in which the naturalist can say that you should value human well-being. You should value it because that is what is objectively valuable. However, the “should” here is not really distinct from an instrumental or prudential sense of “should.” If someone wants to know what they should value in order to be happy, then you can tell them that they should value those things that will really give them happiness, not just the illusion of happiness. Prescriptions are a particular form of descriptions: Doing this will make you happy; doing that will not. The moralist’s orders are like doctor’s orders. Thus, you can admonish your 17-year-old not to value a life of sex, drugs, and rock ‘n’ roll, because such a lifestyle, though titillating in the short term, is not conducive to long-term happiness. In general, for naturalists, there is, and can be, no in-principle distinction between moral and instrumental or prudential goods. Why do the right thing (e.g., abstain from stealing, cheating, lying, etc.)? Because you want to be happy and people who base their lives on theft, deception, and falsehood will not be happy people.*
The consequence, as I noted in an earlier post, is that the naturalist has nothing to say to someone like the Underground Man who honestly does not value human happiness, not even his own. If someone seriously asks me “Why should I value happiness?” I would be tempted to offer a flip answer: “Well, gee, why don’t you try misery for a while?” If someone asks “What is so great about rationality?” likewise I could say “Practice irrationality for a while and see what it gets you!” If the Underground Man replies “I have tried misery that is what I want!” The only answer I could give is “OK. You are welcome to it. Just don’t try to spread any of that misery to me, or I will make you miserable in ways you won’t want!” When people have cut themselves off from rational persuasion, threats must suffice. Further, the Underground Man’s repudiation of happiness is no evidence at all against the naturalist’s identification of the highest good with well-being, no more than a crackpot’s refusal to be reasonable is a rebuttal of logic. Intentional perversity is something that no system of ethics can address.
my favorite scenes in any movie is the very instructive one at the end of The Godfather, Part II, where Al Pacino as Michael Corleone is shown sitting all alone at Christmas, recalling a Christmas of many years before. Most of the friends and family in his recollection are either dead, several killed by him, or will no longer speak to him because they hate or fear him. A life of plots, murder, and lies has gotten him wealth, power, and utter misery. He has it all and he has nothing. At a much lower artistic level, consider the women in Sex and the City (I am basing this judgment on the two or three episodes I ever watched). They have beauty, intelligence, education, wealth, and a degree of freedom that hardly any women throughout history have enjoyed. Yet they are utterly miserable? Why? Because they are nincompoops. They consistently make irrational, selfish, self-deluded decisions and are then astonished and appalled when things turn out the way they always do. Aristotle would fully agree: Crime does not pay, and neither does stupidity.
The questions about Conway’s “Life” and proper function are interesting issues, but are red herrings here that would deflect discussion onto tangential topics. If the notion of telos is the stumbling block, we can do without it. Larry Arnhart, in the book I mentioned earlier, Darwinian Natural Right notes that there are a number of natural desires, common to people across cultures and through history. When these desires are not satisfied people are unhappy and their lives are truncated in a number of ways. When these desires are fulfilled, humans flourish. Alternatively, we may speak of human ecology as Owen Flanagan does in The Problem of the Soul. These are two leading accounts of ethical naturalism, and neither one appeals to the concept of the human telos. I talk about it because I think that Aristotle was on to something. I am not an Aristotelian fundamentalist; I just think that he was a close to right on ethical and political issues as anyone could be 2350 years ago. I also think that a post-Darwinian can accept that when Aristotle talked about the human function, he was talking about something important and real. Humans are supremely, I would say uniquely, well adapted to live the lives of social and rational creatures. Further, humans are happy when their social interactions are successful and their decisions are based on evidence and sound reasoning. Conversely, they are miserable when they are social failures, e.g., nobody likes them (think what a happy camper John Edwards must be these days), and when they have to live with the consequences of irrational decisions. Aristotle may have meant a lot more in talking about eudaimonia and the human telos, but I think what he said at least encompasses what I summarize in the previous three sentences, which I think are true and important.