Reasons for Action and Psychological Capacities

Most moral philosophers agree that if a moral agent is incapable of performing some act ф because of a physical incapacity, then they do not have a reason to ф. Most also claim that if an agent is incapable of ф-ing due to a psychological incapacity, brought about by, for example, an obsession or phobia, then this does not preclude them from having a reason to ф. This is because the ‘ought implies can’ principle is usually interpreted as a claim about physical, rather than psychological, capacities. In this paper I argue for an opposing view: if we don’t have reasons to do things that we are physically incapable of doing, then neither do we have reasons to do things we are psychologically incapable of doing. I also argue that extending the ‘ought implies can’ principle to psychological capacities makes the principle more attractive.