A harm produced by many people acting together raises a question that individual ethics answers badly.
Each contribution may be too small to matter, while the is plainly .
If no single act is wrong, it is unclear where the wrongness of the outcome is located.
One response denies the and insists that each contribution is wrong in proportion to its share.
This preserves the framework and produces conclusions that almost nobody can act on.
A share of one ten-millionth of a harm is not a quantity a person can about.
A second response abandons the individual as the unit of assessment and judges institutions instead.
This is more , because an institution can adopt a rule and be held to it.
It also relocates the problem rather than it, since institutions are composed of individuals.
The most useful move in recent work has been to separate blame from obligation.
Blame requires that an agent could have made a difference, and frequently no individual could.
does not require it, and can attach to participation in a practice that produces harm.
On this account a person may owe something without having done anything .
The obligation is typically to support the arrangements that would stop the harm.
That is a modest conclusion and it has the advantage of being something a person can actually do.
Critics object that it lets participants off too lightly, which is a complaint about blame.
Supporters reply that a theory generating unusable verdicts has not been rigorous but useless.
The disagreement is unresolved and the distinction between the two questions is now generally accepted.