falsify wrong ones. Ethics as a science needs a similar measurement. And the ultimate check of any ethical theses (IMHO) is whether its conclusions are acceptable to mankind. If it fails that check it can be as logical as one can imagine. It simply does not fit human nature and thus has to be discarded. You are aware of the fact that logic does not tell you what is true, but only what is true if something else is true. Each theory, even an ethical one, needs basic assumptions which are believed to be true without any logical cause leading to that. In math they are called axioms. You said that the premises used by the authors are "widely accepted" and thus I understand they are no longer debated and used like axioms. As the logical conclusions derived from those premises lead to ethical conclusions unacceptable to mankind, the premises needs reconsideration. My personal interest in this discussion is based on the fact that we have here in Germany bioethicists as advice givers for parliament. If every bioethicist accept the premises I criticize then they do not share the ethical code written into our constitution and thus are unable to advise parliament in making laws that are in consent with that constitution. This would be a very bad situation -- those experts would have to be removed from their position. If only some bioethicists accept the cited premises while others do not, that would be better. Now how is the