Jumping in here late. Are we assuming--must we assume--that "harms" are like pains felt by particular subjects at particular times?
Basically, I think the following are all legitimate candidates for a morally relevant definition of harm:
Any x is harmed if and only if it is possible for said x to recognize some deprivation.
Any x is harmed if and only if it is possible for said x to recognize some deprivation due to external factors.
Any x is harmed if and only if it is possible for said x to recognize some deprivation due to the actions of other beings.
Any x is harmed if and only if it is possible for said x to recognize some deprivation due to the actions of other persons.
Any x is harmed if and only if it is possible for said x to experience a new sensation of pain.
Any x is harmed if and only if it is possible for said x to experience a new sensation of pain due to external factors.
Any x is harmed if and only if it is possible for said x to experience a new sensation of pain due to the actions of other beings.
Any x is harmed if and only if it is possible for said x to experience a new sensation of pain due to the actions of other persons.
Any x is harmed if and only if said x suffers deprivation.
Any x is harmed if and only if said x suffers deprivation due to external factors.
Any x is harmed if and only if said x suffers deprivation due to the actions of other beings.
Any x is harmed if and only if said x suffers deprivation due to the actions of other persons.
