Jew wrote:Meh. Utilitarianism as a whole breaks down in practice when one realizes that it is impossible to accurately compute utility without being omniscient, and without knowing the future. Not that utilitarianism is therefore unusable; we can still make fairly good guesses about most things. It's just not infallible or entirely objective, which might upset some people. *cough*Ayn Rand*cough*
This is an incredibly senseless criticism. To pretend that this is some 'problem' present in utilitarianism but not in the misnamed 'Objectivism' is ridiculous. One can also be wrong about things perceived to be in one's interest actually being in one's interest; even Rand is sane enough to admit this. Besides, why should this be considered a problem in the first place? Is there any reason why one should be able to determine
absolutely that one would be doing the right thing before it is actually done? This is an advantage, not a problem--life is unpredictable, so an ethical system that recognizes this is more reflective of society that one that does not.
Jew wrote:Rule-utilitarianism seems to break down, though. Consider: act-utilitarianism says it's OK for me to kill a man if his death will cause an increase in utility. Rule-utilitarianism says no, it's not. But what if I can make it look like an accident? I will have increased happiness and no one need ever know I murdered him.
Incorrect. Unless this person's existence would have caused great misery, you would have decreased the net utility in the world. Note that the identification of utility with personal happiness is only found in hedonistic utilitarianism, which has a long history of being criticized even by other utilitarianists--that has already been covered in this thread. If your purpose here is to reject hedonism, I have absolutely no objections there.
Jew wrote:Should I really refrain from a murder that no one will ever know about and that will increase utility, simply because most other murders are bad? Why should I judge the rightness or wrongness of this one action by the rightness or wrongness of other actions? Who am I to deny the public the utility that this murder will bring?
How does no one finding out about it change the fact that your action decreased net utility in the world? This entire example is flawed.