In the earlier discussion of PAS and AVE and of valid requests, active/passive euthanasia, and withdrawing/withholding treatment, we indicated why several important arguments intended to show the wrongness of individual acts of PAS failed. The failure of these arguments does not settle the matter of the permissibility of these individual acts of PAS, however, since there remain slippery slope concerns to address. We have reason not to permit even these instances of PAS, if they would indeed lead us down a slippery slope of killing to disastrous consequences.

Especially with regard to taking life, slippery slope arguments have long been a feature of the ethical landscape, used to question the moral permissibility of all kinds of acts, including prominently in recent years abortion and euthanasia. In fact, the very frequency with which such arguments have been deployed can seem almost a point against them. So often has it been predicted that the heavens will fall, that we shall descend the terrible slope of taking life until we reach the Nazi camps (or what strikes adherents of such arguments as the moral equivalent of such camps), that the very fact that the heavens have not fallen and the camps have not reappeared can seem to weaken slippery slope arguments. The situation is not unlike that of a doomsday cult that predicts time and again the end of the world, only for followers to discover the next day that things are pretty much as they were.