But if that were the case, then moral philosophers - who reason about ethical principles all day long - should be more virtuous than other people. Are they? The philosopher Eric Schwitzgebel tried to find out. He used surveys and more surreptitious methods to measure how often moral philosophers give to charity, vote, call their mothers, donate blood, donate organs, clean up after themselves at philosophy conferences, and respond to emails purportedly from students. And in none of these ways are moral philosophers better than other philosophers or professors in other fields.

Schwitzgebel even scrounged up the missing-book lists from dozens of libraries and found that academic books on ethics, which are presumably mostly borrowed by ethicists, are more likely to be stolen or just never returned than books in other areas of philosophy. In other words, expertise in moral reasoning does not seem to improve moral behavior, and it might even make it worse (perhaps by making the rider more skilled at post hoc justification). Schwitzgebel still has yet to find a single measure on which moral philosophers behave better than other philosophers.

• Jonathon Haidt, discussing the idea that ethical reasoning causes good behaviour, in his book 'The Righteous Mind'.

I found the book-stealing thing quite funny, although I imagine that some of the results described could be explained by popularity; if more people get into / like ethics, then there are more people who might steal library books, more antisocial people who don't respond to emails, etc. This hasn't been demonstrated to my knowledge though, and I'm otherwise inclined to believe that people who spend their days thinking about ethics in the abstract, are simply better at coming up with rationales for their instinctive feelings. Joshua Greene says rights are an example of this, where we need a dictum against whatever our emotions are telling us is despicable, even though we can't find any utilitarian justification for it.