Nice try, but even if my utility for oiled birds was as nonlinear as most people’s utility for money is, the fact that there are many more oiled birds than I’m considering saving means that what you need to compare is (say) U(54,700 oiled birds), U(54,699 oiled birds), and U(53,699 oiled birds)
Nonlinear in what?
Daniel’s utility for dollars is nonlinear in the total number of dollars that he has, not in the total number of dollars in the world. Likewise, his utility for birds is nonlinear in the total number of birds that he has saved, not in the total number of birds that exist in the world.
(Actually, I’d expect it to have two components, one of which is nonlinear in the number of birds he has saved and another of which is nonlinear in the total number of birds in the world. However, the second factor would be negligibly small in most situations.)
He has a utility function that is larger when more birds are saved. If this doesn’t count as caring about the birds, your definition of “cares about the birds” is very arbitrary.
Nonlinear in what?
Daniel’s utility for dollars is nonlinear in the total number of dollars that he has, not in the total number of dollars in the world. Likewise, his utility for birds is nonlinear in the total number of birds that he has saved, not in the total number of birds that exist in the world.
(Actually, I’d expect it to have two components, one of which is nonlinear in the number of birds he has saved and another of which is nonlinear in the total number of birds in the world. However, the second factor would be negligibly small in most situations.)
IOW he doesn’t actually care about the birds, he cares about himself.
He has a utility function that is larger when more birds are saved. If this doesn’t count as caring about the birds, your definition of “cares about the birds” is very arbitrary.
He has a utility function that is larger when he saves more birds; birds saved by other people don’t count.
If it has two components, they do count, just not by much.