Abilities are powers an agent has to perform various actions. They include common abilities, like walking, and rare abilities, like performing a double backflip. Abilities are intelligent powers: they are guided by the person's intention and executing them successfully results in an action, which is not true for all types of powers. They are closely related to but not identical with various other concepts, such as disposition, know-how, aptitude, talent, potential, and skill.
Theories of ability aim to articulate the nature of abilities. Traditionally, the conditional analysis has been the most popular approach. According to it, having an ability means one would perform the action in question if one tried to do so. On this view, Michael Phelps has the ability to swim 200 meters in under 2 minutes because he would do so if he tried to. This approach has been criticized in various ways. Some counterexamples involve cases in which the agent is physically able to do something but unable to try, due to a strong aversion. In order to avoid these and other counterexamples, various alternative approaches have been suggested. Modal theories of ability, for example, focus on what is possible for the agent to do. Other suggestions include defining abilities in terms of dispositions and potentials.
