The good, the bad and the ugly truth about morals

A BROTHER AND SISTER are on holiday in a cottage by an isolated beach and decide it would be intriguing to make love. The location is so remote there is no chance they will be discovered. The sister already takes birth control pills but, to make absolutely sure she will not become pregnant, the brother uses a condom. They enjoy the sex but decide never to do it again and agree not to tell anyone. It will be their secret, one that will draw them closer together.

Was it OK for them to do it?

That was the question posed to an audience at a public seminar, Why Moral Philosophers Need Lots of Help from Psychologists, Anthropologists and Other Social Scientists, at the University of Hong Kong last week.

The speaker, Dr Stephen Stich, professor of philosophy at Rutgers University, New Jersey, US, was surprised when only a couple of people raised their hands to show they thought the siblings were wrong. The reaction to the scenario, devised as an experiment by Dr Jonathan Haidt, a professor in social psychology at the University of Virginia, is normally unequivocal, such is our taboo against incest.

He cited the scenario in answer to a question, following his seminar, about whether reasoning could resolve moral disagreement. Professor Stich said Professor Haidt's scenario - put to a group as part of an experiment - was cleverly constructed so that all possible arguments for the justification of the usual moral arguments against incest were answered in advance.

The claim that incest is morally unacceptable because it can cause regressive deformity was covered by the fact that the couple used two forms of contraception.

Similar arguments, such as, 'it could become a habit' or, 'it could ruin their lives or reputations if other people found out' had also been covered. They had enjoyed the sex and there was no shame or guilt.