I’m a philosopher and cognitive scientist at the University of Waterloo. My current research focuses on social cognition and communication, using tools from philosophy and experimental psychology. Before taking up my position at Waterloo, I held a tenure-track position at the University of Western Ontario (specifically, Huron University College). My favorite parts of the job are working with brilliant and inspiring people and the thrill of discovering new things.
A lifeguard scans the coastline and is horrified to see two children drowning, one at the western edge of the beach and the other at the eastern edge. They are so far apart that the lifeguard cannot save them both — she can save one or the other, but saving both is impossible.
Obviously, the lifeguard is morally obligated to save a child. But is she obligated to save both children?
Traditional philosophical wisdom says that the answer is clearly “No.” And this is because, as the philosopher Immanuel Kant wrote, “Duty commands nothing but what we can do.” This view is so popular that it even has a slogan worthy of a bumper sticker: “ought implies can.”
Philosophers sometimes claim that this “ought implies can” principle is part of commonsense morality. But is it really commonsense? Recently, a team of experimental philosophers decided to find out.
We conducted a series of experiments involving hundreds of participants who read scenarios like the one about the lifeguard. Over and over again, participants overwhelmingly attributed obligations to agents who were literally unable to fulfill them — including the lifeguard, who was judged to be morally obligated to save both children.
At the same time, participants reliably distinguished between failing to fulfill an obligation and being blameworthy for that failure. At least, they reliably made this distinction when the failure was due to physical inability, such as a broken leg or the limits of human endurance. Unfortunately, they were less forgiving when the failure was due to psychological inability, such as clinical depression.
So what does this research show? Theoretically, it shows that “ought implies can” is not part of commonsense morality, which is interesting. Practically, it shows another way that people suffering from psychological conditions face unequal treatment, which is disturbing.