Abstract

This chapter is concerned with the necessity constraint on defensive harming. It first considers whether a defensive option that would cause more harm than some other equally effective option is ruled out as causing unnecessary harm. The chapter argues that it is not. It defends the view, nonetheless, that there is a sense of “necessary” and a sense of “proportionate” such that defensive liability is itself limited to necessary and proportionate harm. The remainder of the chapter defends the view that necessity, effectiveness, and proportionality are all “internal” to liability—that is, that one cannot be liable to suffer harm that is unnecessary ineffective or disproportionate.