Conflicting duties › The meaning of prima facie duty

Ross uses prima facie duty for a characteristic an action has in virtue of belonging to a morally relevant kind. Fulfilling a promise is his standard example. That feature would make the action a duty proper if no competing morally relevant feature intervened.

The terminology is awkward because the Latin expression can suggest something merely apparent. Ross explicitly warns against that interpretation. A prima facie duty is not an illusion that disappears once we understand the situation better. It identifies a real contribution to the moral assessment.

Consider a promise that must give way to an urgent need. The fact that it was a promise still explains a reason for keeping it. What changes is the judgment about which action is required overall. The promise's force and its eventual priority are different questions.

The distinction is sometimes expressed through the idea of a contributory duty. That gloss helps if we remember what contributes: a morally relevant feature of the act or situation, rather than a vote in a numerical calculation. Ross does not provide a universal exchange rate between a promise, a benefit, and a risk of harm.