 All who employ the concept of FMS agree that, under most circumstances, we are morally prohibited from interfering in various ways with a being with FMS even for the sake of another valued creature and its interests, or for the sake of any other value, such as art, justice, or world peace. For instance, we are prohibited from killing a being with FMS for the sake of saving one or several other such beings. Some philosophers discuss this stringent presumption using the terminology of duties and  rights  and focus mainly on the right not to be killed (e.g., Feinberg 1980, pp. 98–104).