Abstract
There is widely thought to be a proportionality constraint on harming others in self-defense, such that an act of defensive force can be impermissible because the harm it would inflict on an attacker is too great relative to the harm to the victim it would prevent. But little attention has been given to whether a corresponding constraint exists in the ethics of compensation, and, if so, what the nature of that constraint is. This article explores the issue of proportionality as it applies to the liability to compensate. The view that some perpetrators are not liable to pay full compensation because doing so would be disproportionately burdensome is clarified and defended, and it is asked what view we should adopt instead. A key step in that inquiry is an argument that someone is liable to bear the cost of compensating for an injury if and only if she would have been liable to bear that same cost in defense against that same injury ex ante.