Abstract

Imagine that, through no fault of your own, you nd yourself at the bottom of a deep well. Thugs have picked up an innocent person | call him Bob | and have thrown him down the well. Bob is now falling towards you. If you do nothing, your body will cushion Bob's otherwise lethal fall. This will guarantee his survival, but it will kill you. If you shoot your ray gun, you vaporize and kill Bob, thereby saving your life. Are you morally permitted to shoot your ray gun?Most people believe that self-defence against an innocent threat such as Bob is permissible. Judith Thomson (1991) and Frances Kamm (1987) have tried to justify this widely held belief. Jeff McMahan (2002) and Michael Otsuka (1994) have argued against it. In this paper, I contend that arguments from both sides of the debate mistakenly take the existence of an important asymmetry between Bob and you for granted. That way, they miss how similar Bob and you are, in that both of you happen to nd yourselves, undeservingly and through no fault of your own, in a situation in which you can secure your own survival only if you kill an innocent person. In this paper, I argue that despite certain differences, we are justi ed in focusing on the simliarities between Bob and you, and that you should thus flip a coin to decide who should live (cf. Broome, 1991). By flipping a coin, you ensure that an indivisible good -- continuing one's life -- is distributed as fairly as is possible without wasting it.