Moral responsibility for actions and omissions: a new challenge to the asymmetry thesis

This paper presents a new challenge to the thesis that moral responsibility for an omission requires the ability to do the omitted action, whereas moral responsibility for an action does not require the ability to do otherwise than that action. Call this the asymmetry thesis. The challenge arises from the possibility of cases in which an omission is identical to an action. In certain of such cases, the asymmetry thesis leads to a contradiction. The challenge is then extended to recent variations of the asymmetry thesis defended by John Martin Fischer and Carolina Sartorio. Finally, a possible objection to the challenge is addressed.