Strictly speaking creationism says not just that life on earth was created, but that it was created by God; and evolution says not just that life has evolved, but that life emerged through evolutionary processes (and not God's act of creation). So they aren't strictly speaking compatible. One could, however, articulate similar views that are compatible. Some have suggested, for example, that God was responsible for the Big Bang, but things have proceeded according to natural processes since then. Compatibility or incompatiblity depends on the details of how you spell the views out.
Your question suggests that answers to the question “What is thefunction of X?’ will have normative implications about what we ought orought not, may or may not, do to Xs. And this fact is puzzling. How,you might be wondering, can certain facts about an object’s functionhave any implications about what I may or may not do to it? And I thinkthat you are right to be skeptical: in the case of ashtrays, functionaldefinitions have no normative implications for us– about what we may ormay not do to them.
However, behind your question may be Aristotle’s “function argument” in the Nicomachean Ethics (I 7), where he argues that information about the “function” (ergon) of humans has implications for what sort of life humans ought to live-- “ought”, that is, if they are going to be well off.
Onmy view, Aristotle’s notion of function does not correspond to any ofthe three notions of function that Nick distinguishes for ashtrays. Todistinguish Aristotle’s notion from those that Nick defines, I’ll referto it as an object’s “real function.” On Aristotle’s view, the notionof an object’s real function plays a significant explanatory function. If I want to know why this hammer has the attributes that it has, I have to understand what the hammer is for. If I want to know why hearts have the attributes they have, I have to know what they are for.Hammers and hearts can be used for all sorts of purposes, but not allof these purposes will be equally useful for such explanatory purposes.
The fact that we put objects to uses other than what they arereally for usually doesn’t much matter– sometimes we can put objects tobetter use than we could if we restricted ourselves to using them onlyfor real function. This statue is quite hideous, but it makes for avery effective doorstop. On Aristotle’s view, there is a significantexception to this general rule. While we might put other objects tobetter use than what they are really for, our own selves are adifferent matter altogether. On Aristotle’s view, if we are going tolive the best life, we must perform our real function and do so well.
I think the really deep question here is why incestuous relationships seem so morally problematic, quite independently of the child-bearing issues. Here are a couple thoughts.
The case of parent-child incest is clearly the most problematic, even when the child is of age. And here, I think the source of concern is power. It's not that it seems utterly impossible for the child, in such cases, to give truly informed consent, but one might wonder how free (or well informed) that consent could be. It's not unlike, that is to say, supervisor-employee or teacher-student relationships, except, of course, that the parent-child relationship is far more intimate and, as a result, far more is at stake for the child.
What, then, about sibling-sibling relationships? Here, there probably aren't the same kinds of concerns as with parent-child relationships. But, continuing the work-world analogy, it is perhaps worth noting that many companies bar relationships between co-workers as well as between supervisors and employees. Why? Well, the usual reason is that such a relationship can cause all kinds of complications: If it's going well, the partners might form a "block" that undermines the "team" as a whole; if it doesn't go well, well, then that's really a mess. And it seems to me something similar might be said of the case of sibling-sibling incest: The intimate, sexual relationship seems to be in an odd kind of competition with the familial one; if the intimate relationship goes sour, it might well threaten the familial one, and the latter seems like something valuable, too valuable to put at risk. Or, to switch analogies, the conflict here is one of a sort that would be familiar to anyone whose ever considered becoming romantically involved with a good friend...or has somewhat unintentionally found oneself waking up next to said friend the next morning.
You'll note that I've focused here on incestuous relationships. I do very strongly think this is the right thing to talk about. One-off sexual adventures are perhaps another matter, and there are plenty of people who've "experimented" with siblings, often as teenagers, without long-standing ill effects. I'm not saying there's nothing morally problematic about that kind of thing, but there seems to be a morally relevant difference between the one-off cases and "making a habit of it". And when one "makes a habit of it", well, that's a relationship.
That said, to address the question you actually asked: If (say) a married man and woman wish to have children, but know that they have serious genetic predispositions to certain illnesses, then that may well give them a responsibility, at a minimum, to seek genetic counseling. If the risks are serious enough, then there may well be moral questions to be asked about whehter they should have children together. In the case of two family members, I take it that we know the risks are reasonably serious.
Whether your empirical speculation is correct, it is of course not for philosophers to say. So let's focus on the question. Let's suppose it turns out that women are intrinsically more intelligent than men. Should women then be accorded special treatment as regards education?
To suppose it would be just to accord women special treatment in this situation, one must suppose that it would be just to treat me a certain way simply on the ground that I was a member of a group that, as a whole, had certain characteristics I may or may not myself share. For note that it is consistent with the supposition that women, as a group, are intrinsically more intelligent that men, as a group, that I am the most brilliant person in the world. Why I should suffer some educational disadvantage in this case is very unclear. In short: Unless the differences between the groups are so large as to be essentially exclusive, then differential treatment is unjust, because it results in differential treatment of individuals.
For this reason, I myself find the question whether there are intrinsic differences of the sort you mention of no great interest. There is really no prospect of our discovering that there are differences in intrinsic aptitude for, say, mathematics that are as great as would be required for any policy decision justifiably to take them into account.
It is difficult to see why a zombie couldn't do all the behavioural things we do, and indeed just as efficiently and effectively as we do. But that wouldn't show that consciousness could not arise through evolution, since it might be that we do what we do with the help of consciousness.
But maybe consciousness doesn't even help us do what we do: it's just a by-product of the way we do what we do. But even in this case, it might arise through an evolutionary process, just like the lub-dub sound of a beating heart.
But suppose now that consciousness does play a causal role in the way we do what we do. Is there any reason why the specific consciousness of ourselves as a free agents might arise through natural selection? Well (and here I am just speculating) maybe a creature that feels in control tends to do better in the world, and that feeling of control leads naturally to an idea of free will, even if it turns out that the idea is ultimately incoherent. This takes us back to the by-product idea. If our intuitive concept of free will is incoherent, it may be difficult to see how it really helps us act effectively; but it might still be a result of an evolutionary process if it is a by-product of something else that does help us to act effectively.
I guess I would like to know from someone who thought such things were indications of the workings of a deity what sorts of patterns would count to them as not being indications of a deity. I'm inclined to think that some sort of order is a simple requirement of there being a universe at all, and so it seems that some indications of such order--whether highly complex or simple--would inevitably be evident in that universe. As a result, it is difficult for me to see why some particular patterns would indicate anything religiously significant--after all, it is not as if the patterns themselves are divine signatures or fingerprints or the divine equivalent of DNA evidence. That one can have a religious response to such things, as Richard Heck proposes, I don't doubt; but that such a response is somehow rationally supportable, I do doubt.
Developing technologies have always caused new ethical challenges to arise, often by making once impossible states of affairs possible. Insofar as our ethical thinking has failed to take account of these new possibilities, our ethical systems will be tested. But I see no reason to think that foundational ethical facts, like the wrongness of causing gratuitous pain to a sentient creature, are under any threat from new inventions.
You probably have in mind developments like in vitro fertilization and cloning. These developments challenge us to think harder about what it is about what qualities are really at the heart of moral personhood -- is it the mere biological fact of human specieshood, or is rather certain capacities, like being able to feel pain, or being able to reason? They also raise questions about what human beings ought to have the right to try to control, since they offer us the prospect of controlling things we couldn't at earlier times in our histories.
Notice that techonological developments can also make it easier for us to follow our consciences. We now have the technological wherewithal to feed everyone in the world. What's lacking now is the will.
Many people think that the position is tenable. I have my doubts. Showing that life could have originated *only* by natural processes (without any supernatural intervention) seems to me at least unlikely, if not impossible. (Doing so would furnish us with a new argument against the possibility of Descartes' Evil Genius.) It is more plausible to suppose that life actually did originate by natural processes. This more plausible claim, I think, would not do away with any pragmatic need for the existence of a deity. I do not think that the motivation for belief in God stems from things we can't explain. The idea of a "God of the gaps"--a God we postulate to explain "the gaps" left by science--does not seem to me a genuinely religious idea. Belief is God seems often motivated by a sense of gratitude and/or a felt need for forgiveness. And these would remain even if life originated naturally.
Of course evolution could be proven wrong. Maybe we will find out that our planet was actually created by an alien race. Once you dig deep enough, you can actually see the scaffolding they set up. Maybe our ancestors were middlemen on a distant planet who were sent away on a spaceship because they were unwanted, and then they crash landed on the earth and created human society. Just as The Hitchhiker's Guide says. Or maybe human beings came into existence pretty much as they are, roughly 6000 years ago, as fundamentalists think.
In some vague sense, just about any such thing could have happened. But until there is strong empirical evidence to the contrary, scientists will continue to presume the truth of some form of the theory of evolution.