Researchers Seek Roots of Morality in Biology, with Intriguing Results opens with a pair of moral dilemmas:
You are the night watchman at a pediatric hospital. An accident in the ventilation system has caused deadly fumes to enter the air ducts, headed straight for a ward with five children. If you do nothing, the fumes will kill them. If you hit a switch, the fumes will be redirected toward a room with a single child. Should you hit the switch?
You’re a doctor. You have five patients who will die without organ transplants, and one healthy patient who could provide those organs. Is it morally acceptable to sacrifice him in order to save the other five?
Another pair of moral dilemmas:
In one, you are driving along a deserted highway when you see a man bleeding by the roadside. You stop to help, and he asks you to drive him to a hospital. If you do, his blood will ruin your new leather seats, for which you just paid $500. Is it morally acceptable to leave him bleeding on the road? If not, then is it morally OK to ignore a fund-raising letter asking you for a $500 donation, sufficient to save the lives of 50 children who otherwise will die of a treatable disease?
Scientists have used functional magnetic resonance imaging (fMRI) to detect brain activity when people pondered moral dilemmas:
In a sample of 60,000 people taking an online survey (at moral.wjh.harvard.edu), “people make very, very rapid judgments about moral dilemmas, and there is very little variation in what they consider permissible,” says Marc Hauser of Harvard University, Cambridge, Mass. The power of moral intuition “goes strikingly against the dominant view in philosophy that we consciously think these things through.”
He suspects that these moral intuitions include the understanding that committing an inherently evil action, even as a means to a good end, is wrong. That would explain why most people view throwing passengers off an overfilled lifeboat (an inherently evil act) to save the others aboard as morally repugnant. But flipping a switch (morally neutral) to redirect an out-of-control trolley headed for five trapped workers, even if that will kill one worker, seems morally acceptable.
Biologists also are studying whether something in our past might explain our moral intuitions. An evolutionary approach suggests that behaviors that helped our ancestors survive are wired into us, too. People who helped kinsmen in the here and now, such as the man bleeding by the road, could count on help when they themselves were in need. Helping someone far off, to whom they had no connection, would have brought no dividends. According to this view, we inherited the first inclination but not the second.
There also seems to be an intuitive heuristic that says it is morally wrong to cause certain deaths even when you think, or hope, that doing so will prevent a death in the future. That might underlie our repugnance at throwing people off a sinking lifeboat, or at making Sophie’s choice. “There are limits to what moral systems are biologically possible,” Prof. Sinnott-Armstrong says.