It’s a simple enough question: Does a paralyzed man powerless to rescue a drowning girl still have a duty to save her?

Many philosophers have quickly answered in the negative to those sorts of questions, citing the pithy principle of “ought implies can.” Less succinctly, it means that people are only morally obligated to perform the duties they’re capable of performing. Recently, however, the conclusions of a study published in PLOS-One have sought to upturn that philosophical bit of wisdom. The study authors presented a series of eight similar scenarios, including the paralyzed bystander one, to online test subjects and found that participants nearly always attributed moral obligations to people unable to complete them.

"In one experiment, participants considered a case where two swimmers are drowning," illustrated lead author Wesley Buckwalter, a postdoctoral researcher in the Department of Philosophy at Waterloo University, in a statement. "Because the drowning swimmers are so far apart, the lifeguard on duty can save one or the other but not both of them. Despite acknowledging that the lifeguard is literally unable to save both swimmers, the overwhelming majority of participants judged that the lifeguard was still obligated to do so."

Moral Duty

Buckwalter and his colleague Professor John Turri, also of Waterloo University, recruited new subjects through Amazon’s Mechanical Turk for each individual experiment.

In the first, participants determined the moral obligation of someone asked to pick a friend up from the airport but later being physically or mentally unable to. The second experiment involved a playground safety worker unable to pick up broken glass in a location where barefooted kids often play, while in the third, subjects were asked to imagine themselves as the ailing car buddy from the first experiment. The fourth was the lifeguard scenario; the fifth involved either a bystander paralyzed since birth or suddenly struck with paralysis upon seeing the drowning girl; the sixth detailed a man unable to swim out to the girl in time, either because he lacked the individual swimming prowess to or because no human would have been capable of swimming that fast; and lastly, the seventh compared someone’s moral and legal obligation presented by the scenario in the fifth experiment.

Across all these experiments, regardless of the varying conditions, around 90 percent of participants attributed a moral obligation to the fictional bystanders, even as they acknowledged their inablity to fulfill it. Participants were less willing to declare the man had a legal obligation to save the drowning girl in the seventh experiment, though. Buckwalter and Turri’s eighth experiment confirmed a trend they noticed throughout the study, as participants rarely considered people blameworthy for failing to meet their moral obligation because of a physical limitation.

However, this didn’t prove to be true when the limitation was a mental one, such as a panic attack — participants were then much harsher on the avatars. "People are less willing to believe that an agent is unable to drive a car due to clinical depression than due to physical injury," explained Professor Turri. "Moreover, people are more willing to blame agents suffering from psychological inabilities. This asymmetry may reflect the assumption that people can just get over mental inabilities, such as clinical depression, in ways that they cannot just get over, say, a broken leg."

In other words, while most of us consider it Superman’s moral obligation to save Metropolis from Lex Luthor — regardless of how sick he is — we extend much more sympathy for his failure if he’s been struck by kryptonite rather than by depression. Darkly funny as that might be, this inconsistent distinction can carry serious everyday consequences as the authors note that the “motivation to blame someone often leads people to distort causal facts and interpret them in a way that justifies their negative reactions, a phenomenon known as blame validation.”

Buckwalter and his team hope to perform more research on why this long-lasting and unfounded stigma against mental illness continues to exist.

Source: Buckwalter W, Turri J. Inability and Obligation in Moral Judgment. PLOS-One . 2015.