Imposing the duty of gratitude

Normally if Alice did something supererogatory for Bob, Bob has gained a duty to be grateful to me. It is puzzling that we have this normative power to impose a duty on someone else. (Frank Russell’s “And then there were none” story turns on this.)

In some cases the puzzle is solved by actual or presumed consent on the part of Bob.

Here’s the hard case. Bob is in the right mind. Bob doesn’t want the superegatory deed. But his not wanting it, together with the burden to Bob of having to be grateful, is morally outweighed by the benefit to Bob, so Alice’s deed is still good and indeed supererogatory.

I think in this case, Bob indeed acquires the duty of gratitude. We might now say that imposing the burden of gratitude was indeed a reason for Alice not to do the thing—but an insufficient reason. We can also lessen the problem by noting that if being grateful is a burden to Bob, that is because Bob is lacking in virtue—perhaps Bob has an excessive love of independence. To a virtuous person, being grateful is a joy. And often we shouldn’t worry much about imposing on someone something that is only a burden if they are lacking in a relevant virtue.