At Legal Theory Blog Solum has another bit on the 'demandingness' objection to utility theory, this time by way of Lafave. The basic objection is that utilitarianism demands too much of us, so it can't be the right moral theory.
Lafave adds in a gloss on the difficulty of adherence to "common-sense morality" if one believes utilitiarianism. The 'demandingness' objection is a might weird. What it comes down to is the view that morality can't be too hard. If we actually have to sacrifice things, well, better not. It is usually cast along the lines that what is going on is that utility theory is not just demanding (it's okay for morality to be a little demanding), it is too demanding. Can't properly ask for all that. Well, can't morality ask for all that? The common-sense morality we are normally so fond of asks an awful lot - like dying for one's country. Dying seems to be pretty much it in terms of sacrifice. Along the same lines, one wonders what to make of a good deal of christian theology. Avoiding sin seems to me about as demanding as utility theory (which is why I have always had a fondness for the Cathars). How much is too much?
Another road in is the argument that utility theory is psychologically difficult (or impossible). Set aside the supposition that moral theory must have motivational effect. There are problems here. One is that common-sense morality is pretty useless as a standard, for painfully obvious historical and cultural reasons. Another problem is that the argument seems to suppose that truth of the matter is the best way to think about problems. There are lots of situations in which that is not the case. Approximation and satisficing strategies are plentiful and effective. This pyschological difficulty point is an empirical claim without evidence. We use fictions all the time to solve all sorts of problems.
Given the uncertainty about effects of conduct, it is a little surprising that the 'demandingness' objection gets raised so often. A better complaint is that there does not seem be any way to figure out, even in vague approximation, what should be done under act utility theory.