ABILITY AND THE PAST

Two principles regarding agents’ specific ability are proposed. The first claims that ordinary agents (i.e., agents who are not backward time traveler) always lack the ability to do otherwise in the past, while the second principle observes that it is at least possible for some agent to have the ability to perform some action in the past. These two principles further give rise to three desiderata for a true account of ability. Two accounts of ability in the literature—the conditional analysis and the dispositional account—are then examined but they both fail to meet the desiderata simultaneously. A modal principle of ability is motivated at the end.