In this paper, I examine Jeff McMahan’s arguments for his claim that we are not human organisms, and the arguments of Derek Parfit to the same effect in a recent paper. McMahan uses these arguments to derive conclusions concerning the moral status of embryos and permanent vegetative state patients. My claim will be that neither thinker has successfully shown that we are not human beings, and therefore these arguments do not establish the ethical conclusions that McMahan has sought to draw (...) from the arguments in respect of the moral status of embryos and PVS patients. (shrink)