http://www.economist.com/node/21530078IN THE grand scheme of things Jeremy Bentham and John Stuart Mill are normally thought of as good guys. Between them, they came up with the ethical theory known as utilitarianism. The goal of this theory is encapsulated in Bentham’s aphorism that “the greatest happiness of the greatest number is the foundation of morals and legislation.”
Which all sounds fine and dandy until you start applying it to particular cases. A utilitarian, for example, might approve of the occasional torture of suspected terrorists—for the greater happiness of everyone else, you understand. That type of observation has led Daniel Bartels at Columbia University and David Pizarro at Cornell to ask what sort of people actually do have a utilitarian outlook on life. Their answers, just published in Cognition, are not comfortable.
One of the classic techniques used to measure a person’s willingness to behave in a utilitarian way is known as trolleyology. The subject of the study is challenged with thought experiments involving a runaway railway trolley or train carriage. All involve choices, each of which leads to people’s deaths. For example: there are five railway workmen in the path of a runaway carriage. The men will surely be killed unless the subject of the experiment, a bystander in the story, does something. The subject is told he is on a bridge over the tracks. Next to him is a big, heavy stranger. The subject is informed that his own body would be too light to stop the train, but that if he pushes the stranger onto the tracks, the stranger’s large body will stop the train and save the five lives. That, unfortunately, would kill the stranger.
Dr Bartels and Dr Pizarro knew from previous research that around 90% of people refuse the utilitarian act of killing one individual to save five. What no one had previously inquired about, though, was the nature of the remaining 10%.