There’s an interesting article in this week’s Nature (well, strictly last week’s now, but still the most recent one I have here), on research into the neural basis of disgust, and its links to ethical judgements. (Nature 447 (2007), 768-771) It would seem that, when people judge things to be ethically disgusting, they are using the same parts of the brain, and in much the same way, as when they judge faeces to be disgusting. There’s also a lot of interesting work on the human tendency to punish undesirable behaviour, and on the origins of compassion and cooperation, although that doesn’t appear in this week’s issue. It all appears to be perfectly natural.
This is a problem for ethics, because instincts hardwired into us by evolution in order to promote the spread of our genes in future generations are not generally considered to be the right sorts of things on which to found a system of ethics. Ethics should be grounded on universal truths, not a set of feelings cobbled together by the essentially random process of evolution because they were helpful when it came to surviving on the prehistoric African steppes.
The problem can be made sharper. According to the article, the extent to which people are politically and ethically “conservative” (as in right wing) is quite strongly correlated with their tendency to be disgusted. People who are only disgusted by core disgusting things, like faeces and rotten meat, are more much likely to be liberal than those who are also disgusted by, say, the idea of eating soup that’s been stirred by a thoroughly disinfected, but used, fly-swatter. However, the extent of disgust is, fairly clearly, something that varies, on a personal level, in the same way as taste in food, or in art. (I’m not a counter-example. I’m liberal, and the range of things that disgust me is relatively small.) It’s certainly not something that can make an “objective” decision between conservatism and liberalism.
Now, it might be tempting for liberals to say that this just shows that we should ignore disgust in formulating our ethics. I think that we should ignore disgust, but this doesn’t show it. There are, almost certainly, similar variations in the level of concern that people show about injuries to others, or fairness, or group loyalty. They also seem to be similarly evolutionarily grounded. Thus, if these are reasons to ignore disgust, and thus some people’s aversion to, say, homosexual acts, they are also reasons to ignore compassion, and thus some people’s (including my) aversion to, say, torturing people. We also can’t simply accept all the judgments that these faculties produce, because they are contradictory. Some people find black people disgusting, and other people find it disgusting to find black people disgusting. These faculties cannot help us when they disagree among themselves.
Essentially, these considerations seem to show that we should not rely on our ethical judgments, our consciences, when making ethical decisions or devising ethical theories. But that’s all we have. It’s all that ethicists ever work with.
There have always been theoretical reasons to worry about our moral judgments, because it has never been clear how they could be accurate, or what they could be about if they were accurate. However, these results produce a different problem: they provide actual empirical reasons to think that our ethical judgments do not track anything that could underpin ethics, as traditionally understood. They do that by providing reasons to think that they track something else.
I think that ethics needs to be radically rethought, both in terms of methods, and in terms of actual results, to account for this. I suspect that the result will not be able to support some of the traditional functions of ethics; in particular, I strongly suspect that it will not even support the criticism of others, much less their punishment. But that is a bigger topic, to which I hope to return.