Experimental philosophy gets real

“Ten bucks an hour? Sweet!”

A new study confirms what philosophers have long suspected: ordinary folk disapprove of violently killing innocent bystanders. Published this week in Science, the study is turning heads less for its conclusion and more for its methods. Studying folk intuitions in moral dilemmas is nothing new. But in response to criticism that his laboratory experiments lack ecological validity, Harvard’s Joshua Greene decided to take his research out of the lab and into the field.

“Sure, people will say that pushing a man in front of a speeding trolley is wrong on paper,” says Greene, the study’s lead author. “But what happens when they actually get out there and kill a man? Still wrong? Nobody knew because nobody had tested it.”

With that guiding insight in mind, Greene and colleagues placed their experimental subjects in planned but very real moral dilemmas. So far, they’ve confirmed that the folk disapprove of harvesting the organs from a hospital passerby to save ailing patients; executing an innocent man to appease a violent mob; and shoving a large man from a footbridge to stop a runaway trolley below. Next up, says Greene, is an experiment testing the permissibility of flipping a switch to drop a large man from a footbridge to stop that same runaway trolley. “We’re still waiting on IRB approval for that one,” Greene notes. “But we’re very excited to see how it turns out.”

While the results have been invaluable, research costs have become prohibitive, and Greene’s next trolley experiment might be his last. “At first we followed the lead of the psychology department and required each of our majors to participate in one study,” explains Harvard philosophy chair Sean Kelly. “The problem is, we’re running out of majors.” Trolley problems are especially labor intensive, often requiring five “fresh” volunteers per trial and dozens of trials per study. On the bright side, Kelly notes, this kind of research should do something to reduce the glut of PhD’s being produced each year by philosophy programs.