Imagine that your body has become attached, without your permission, to that of a sick violinist. The violinist is a human being. He will die if you detach him. Such detachment seems, nonetheless, to be morally permissible. Thomson argues that an unwantedly pregnant woman is in an analogous situation. Her argument is considered by many to have established the moral permissibility of abortion even under the assumption that the foetus is a human being. Another popular argument is that presented by Singer and Unger to the effect that even those who are moderately prosperous are morally obliged to help the poor if they can do so at relatively small cost to themselves. The paper (published under the pseudonym 'Nicola Bourbaki') considers the question whether these two arguments can be simultaneously valid.