More about Sam Harris, who argues (here and in a forthcoming book) that "science can determine moral values"--
Harris's real goal is to face down critics of his anti-religious stance in The End of Faith. If you don't have God, the argument goes, you can't have morality. That concerns Harris a lot, because he very much wants to have morality. What drives his first book is a horror at appalling things done in the name of religion--the 9/11 mass-murder, honor killings, the slaughter of innocents prescribed by God in the bible, etc. "But if God does not exist, everything is permitted!" Harris wants to answer that sort of critic.
So: morality is objective, he thinks. In other words, honor killings are really wrong, and not just wrong to us, while permissible for others, elsewhere. There are robust, non-negotiable truths about morality. And they're not based on anything up there in the sky. Those are his intuitions, and they're mine too. But now how does science enter into morality?
Let's have a vivid example, and not one of the overworn ones. In the February issue of National Geographic I read an amazing story that mentioned (among many other things) a practice called "mingi killing." The Kara people of Ethiopia have a belief that babies have to be killed under certain conditions, including when their top teeth erupt before their bottom teeth. Otherwise the mingi might spread, causing bad luck. The author tells of a woman who bore and killed 12 children. How? "Sometimes the child is abandoned in the bush, its mouth filled with earth; sometimes it is hurled into the river." You'll be glad to know the Kara king recently decided to ban this practice, at the urging of the Ethiopian government and NGOs.
OK--so mingi killing is morally wrong, and was wrong even before it was abolished by the king. That's what Harris would probably say, and I agree. The religious moralist wonders how we can be entitled to that view, if we don't countenance a supreme being who objects to mingi killing. I'm just guessing what will be in Harris's book, but I'll bet he's going to say it's pretty weird to look skyward for a reason why mingi killing is wrong. The wrongness doesn't proceed from some supernatural realm. It's right here in our world--in the Kara tribe, to be exact. You can see the wrongness by looking closely at the facts themselves--babies, killing, parents, what it's like to have dirt in your mouth, etc.
So how is science supposed to help? More guessing. What would the NGOs have said to discourage mingi killing? They might have gone into the science of tooth development, making clear that it's equally normal when top teeth erupt first. They might have collected some data to show that tooth eruption patterns make no difference at all to future events. If the Kara thought babies don't suffer when abandoned or drowned, they could have given them evidence that they do. Surely they knew that parents didn't like exposing their kids (they don't) but I suppose they could have gathered data that showed the trauma lasted for years, or that relatives were affected as well. It's possible that the impact on the tribe wasn't fully understood.
So--for the Kara to see the wrongness, they don't need religion, they need science. So, perhaps, the argument goes. But here's what bothers me. All that science could be persuasive, but it will have leverage only if the Kara already believe something like this basic principle--
(P) It's morally wrong to kill a baby if you have no good reason to do so.
The science relates to whether they have a good reason to kill these babies, and whether they have good reasons not to. But the science doesn't tell them whether or not to accept this principle. To decide, you need to delve into some difficult issues. Do babies really count, just like adults? There are reasons to say they do, reasons to say they don't. If they do count, just what is it that makes killing wrong? There are reasons to say this, reasons to say that. I think reasonable people, after a long careful discussion, will converge on agreeing to P. It's the most reasonable thing to think. But science isn't going to prove it.
So--yes to the idea of objective wrongness. Yes to the idea that it doesn't rain down from the heavens. Yes to the idea that science can be enormously helpful in revealing what's right and wrong. But no, science does not, all on its own, determines moral values. There's also such a thing as rational reflection on right and wrong, which can be fruitful, progressive, and gradually generate consensus. That's what secularists have to proffer as the alternative to religion-based ethics. Sadly, "rational reflection" doesn't have quite the stellar image of "science," but the truth is, we can't discover what's right and wrong without it.