Would it make any sense to tell your friend, stranded at the side of the road, that she ought to drive you to the airport? The answer seems to be an obvious no (after all, she can’t drive you), and most philosophers treat this as all the confirmation they need for the principle.

Suppose, however, that the situation is slightly different. What if your friend intentionally punctures her own gas tank to make sure that you miss the flight and she gets the job? In this case, it makes perfect sense to insist that your friend still has an obligation to drive you to the airport. In other words, we might indeed say that someone ought to do what she can’t — if we’re blaming her.

Three decades after Professor Sinnott-Armstrong made this argument, we decided to run his thought experiments as scientific ones. (We partnered with Professor Sinnott-Armstrong himself, along with the philosopher Felipe De Brigard.) In our study, we presented hundreds of participants with stories like the one above and asked them questions about obligation, ability and blame. Did they think someone should keep a promise she made but couldn’t keep? Was she even capable of keeping her promise? And how much was she to blame for what happened?

We found a consistent pattern, but not what most philosophers would expect. “Ought” judgments depended largely on concerns about blame, not ability. With stories like the one above, in which a friend intentionally sabotages you, 60 percent of our participants said that the obligation still held — your friend still ought to drive you to the airport. But with stories in which the inability to help was accidental, the obligation all but disappeared. Now, only 31 percent of our participants said your friend still ought to drive you.

Professor Sinnott-Armstrong’s unorthodox intuition turns out to be shared by hundreds of nonphilosophers. So who is right? The vast majority of philosophers, or our participants?