Does the Epistemic Quality of Reasons Explain Our Degree of Responsibility?

Photo by Marco López on Unsplash

Imagine that John, having agreed to pick up his friend from the airport, has failed to do so. When his friend confronts him, he makes it clear that his mother was suddenly sick in the hospital. As a result, the amount that John is considered morally responsible for breaking a promise to his friend to pick him up is diminished. But would that be the same if John…