This is a class of objections that can be universally applied to any moral or ethical system. I have seen a fair share of them used against utilitarianism. The objection involves setting up a hypothetical (and almost always exceedingly improbable) situation whose results, no matter what choices are made, will be highly unsatisfactory to those with common moral sensibilities. The situation is then posed to a proponent of a particular moral theory. The course of action recommended by their theory (or any other) will inescapably lead to dramatically poor results. The challenger then triumphantly observes that the application of the theory leads to consequences so unacceptable as to disqualify it from any claim to moral value. (In effect, this is precisely analogous to a foundering company hiring a new president, and then immediately challenging his or her leadership, on the basis of the company's pre-existing financial woes.)
I expect that my reader is sufficiently astute that she or he would feel insulted by my pressing the subject of the obvious flaw in this objection. Yet, in specific cases, one might easily overlook its failure to deliver unto a moral system any substantive criticism.
Common examples refer to castaways who need to kill one or more of their own in order to survive; a society whose happiness necessarily depends upon the suffering of the few; or a just punishment whose execution will cause widespread misery.
This leads to...
Certain ideals, justice for example, are commonly so esteemed as to be held inviolable by any "good" moral system. This is demonstrable nonsense, to anyone who has more than one ideal. For when those ideals come into conflict, one of them must necessarily be sacrificed. This fact is no blow to a moral system. (A person who has only one ideal, which is not goodness itself, should be referred to my previous essay.) The objection rests upon the fact that gross violations of the ideal are always perceived as travesties against goodness. There may indeed be a strong correlation - perhaps strong enough to justify a strict rule regarding preservation of the ideal. But no such correlation is perfect. A rule created for the good must be broken when it can be shown, with sufficient clarity and certainty, to work against the good in a particular case.1 The fact that such a conflict might occur speaks only against the rule -- not against the ideal nor the morality.
1. There can of course be complications to the evaluation of whether a rule works against the good, including consideration of the value of the rule itself and of the probability that the evaluation is incorrect (given past evidence in favor of the rule's applicability). Therefore, assume that I speak only of cases in which the "clarity and certainty" are sufficient even in light of these considerations.