Suppose you are sitting at your desk, reflecting on a moral question. Now suppose that as you are reflecting on this question, you happen to be looking around at a somewhat disgusting scene. Perhaps there is a half-eaten apple on the desk, or a bad smell in the room, or maybe you just didn’t have an opportunity to wash your hands.
I sometimes encounter the claim that experimental studies have shown that people’s moral intuitions can be pushed around in surprising ways by subtle situational factors like these. It is then sometimes suggested that philosophers need to think more about the deeper philosophical implications of this kind of ‘instability’ in our moral intuitions.
This claim strikes me as a serious misrepresentation of the present state of the empirical literature. In fact, it might be more accurate to say that existing studies provide evidence that these factors do not influence people’s moral intuitions. At the very least, it would be hard to deny that a whole bunch of recent studies suggest that people’s moral intuitions are surprisingly stable.
As many of you know, one of the most important things going on in psychology these days is the attempt to replicate certain widely-known existing findings. Work in social psychology has led to numerous findings that showed a certain cuteness/flashiness/clickbaitiness. Many of these findings have become highly influential within philosophy. However, in a number of cases, more careful systematic work over the past few years has shown that these findings consistently fail to replicate. It is now widely thought that many of these supposed effects actually don’t exist at all, and that the original findings were instead the result of publication bias or questionable research practices.
Many researchers now hold precisely this view about the findings philosophers sometimes invoke to demonstrate the instability of moral intuitions. More specifically, a series of early studies in social psychology were taken to show that people’s moral intuitions could be affected by incidental manipulations of disgust. This work got a lot of attention, and it was widely seen as a challenge to a certain methodology in moral philosophy. But follow-up work now seems to suggest that this effect doesn’t actually exist. I worry that this more recent work is not sufficiently well-known in philosophy, but it strikes me as very important and worth examining.
First, a direct replication found no effect of cleanliness on moral judgment. Second, an influential meta-analysis indicates that, after correcting for publication bias, there is no significant effect of incidental manipulations of disgust on moral judgments. Third, a recent study checked for moderation with an enormous sample size and, again, found no effect at all.
These results are truly surprising. Naively, prior to reading any empirical work, I would have assumed that making people feel more disgusted would change their moral judgments. These studies suggest that this naive understanding is mistaken. People’s moral intuitions are more stable than one would have thought.
Of course, it would be possible for philosophers to challenge this experimental evidence, and I would be very interested to hear such challenges However, what we should absolutely not do is to simply ignore it. That is to say, it would definitely be a big mistake for us to continue writing metaphilosophical papers on the implications of empirical results suggesting that moral intuitions are less stable than one would have thought without engaging with the evidence suggesting that moral intuitions are actually more stable than one would have thought.