Abstract 

For Kant, it can never be permissible to kill an innocent person. This includes traditional cases of necessity, i.e. cases in which one would need to take the life of another to preserve one’s own. The textbook example is that of the ‘plank of Carneades’, which can be found in Cicero’s De officiis: When shipwrecked on the high seas, is it permissible to wrest a plank from the hands of someone who has already seized it? Kant discusses the case in the introduction to the Doctrine of Right (1797). Predictably, his answer is negative. But he also argues that the perpetrator cannot be convicted in a human court of law. The deed, though wrongful, is ‘unpunishable'. I examine Kant’s argument and its implications within in their historical, philosophical and legal context.