Well the ten pounds still exists either way. You'd have to argue that there's more utility in Bentham owning the £10 than the mugger owning the £10, and that the difference in utility between them is greater than the utility of a finger.
I imagine you could define utility that way, but presumably the mugger could increase the cost (two fingers? an arm?) until the argument works. Also, if you do definite a utility function like that (say, "there is more utility in this £10 being mine rather than yours than the utility of your arm") then that's a pretty questionable morality.
The mugger, through no coercion of Bentham, chooses to go down a finger. It is obvious that the mugger has an insane utility function, but it isn't obvious that Bentham letting him act it out is causing a drop in overall utility.
If the mugger doesn't want his own finger, it is Bentham can choose to trust him that 9 fingers are better than 10. Maybe the mugger is even behaving rationally, maybe the 10th finger has cancer, who knows. As the story illustrates, giving him $10 didn't stop him from losing his finger. There are many factors here that make the situation unclear.
Not really, my utility function weighs some mugger being hurt at 0
> Or is the utility function being presumed here lacking
They're all lacking in someway, so sure.
Yup. According to which utility function? Certainly not mine.
My point is that, is that so clear? Or is the utility function being presumed here lacking?