A decade ago, I traveled to Princeton to spend some time with a young philosopher who had decided to start scanning people’s brains. I was working on a book about the history of neurology, called Soul Made Flesh, and I was fascinated by how the study of the brain had emerged from a scientific attempt to save souls. I wanted to end the book with a look at how scientists study the brain 350 years later, and during my research I discovered the work of Joshua Greene. He was taking the arguments that moral philosophers had developed over many years and testing them out on flesh-and-blood brains, monitoring neural activity as people worked through moral problems.
In addition to putting Greene into my book, I ended up writing a profile of him called “Whose Life Would You Save?” for Discover (which you can also read in a collection of my articles available at Byliner). Here’s how it starts…
Dinner with a philosopher is never just dinner, even when it’s at an obscure Indian restaurant on a quiet side street in Princeton with a 30-year-old postdoctoral researcher. Joshua Greene is a man who spends his days thinking about right and wrong and how we separate the two. He has a particular fondness for moral paradoxes, which he collects the way some people collect snow globes.
“Let’s say you’re walking by a pond and there’s a drowning baby, ” Greene says, over chicken tikka masala. “If you said, ‘I’ve just paid $200 for these shoes and the water would ruin them, so I won’t save the baby,’ you’d be an awful, horrible person. But there are millions of children around the world in the same situation, where just a little money for medicine or food could save their lives. And yet we don’t consider ourselves monsters for having this dinner rather than giving the money to Oxfam. Why is that?”
Philosophers pose this sort of puzzle over dinner every day. What’s unusual here is what Greene does next to sort out the conundrum. He leaves the restaurant, walks down Nassau Street to the building that houses Princeton University’s psychology department, and says hello to graduate student volunteer Nishant Patel. (Greene’s volunteers take part in his study anonymously; Patel is not his real name.) They walk downstairs to the basement, where Patel dumps his keys and wallet and shoes in a basket. Greene waves an airport metal-detector paddle up and down Patel’s legs, then guides him into an adjoining room dominated by a magnetic resonance imaging scanner. The student lies down on a slab, and Greene closes a cagelike device over his head. Pressing a button, Greene maneuvers Patel’s head into a massive doughnut-shaped magnet.
Greene headed off to Harvard a couple years later, where he’s now an associate professor of psychology. Over the years other scientists have also taken up the study of moral neuroscience, but Greene still stands out among them thanks to the philosophical rigor with which he thinks about the nature of morality. Over the years, he’s expanded his research from the basic biology underpinning morality to the different ways that it gets played out in human societies–and how, paradoxically, different forms of moralities bring people into conflict.