A version of the tragedy of the commons "concerns the fishermen of Gloucester. There are lots of fishermen; there are lots of fish in the outer banks; each fisherman wants to maximize his catch of fish; no fisherman can influence the behavior of any other fisherman. Each fisherman catches as many fish as he can until the stocks are depleted and everyone goes bankrupt. The community is worse off. They would have been better off if each had reduced his catch.
Look at it this way: each fisherman has the choice of either (a) catching all the fish he can, or (b) reducing his catch. Each reasons as follows: "if others are going to reduce their catch, then I am best off catching all I can. I'll make more money, no one will be the wiser, and the fish will not be depleted. (This may be called "free-riding on the forbearance of others.") If others are not going to reduce their catch, then I am best off catching all I can as quickly as possible -- why should I voluntarily reduce my catch when no one else is going to do so? After all, the stocks will soon be depleted anyway. Therefore, no matter what others are going to do, I should catch all I can as quickly as possible."
This fisherman's line of thinking is perfectly reasonable and based on his correct calculation of his own welfare (evaluated hedonistically if you like). But when all fisherman make the same judgment, and each does what's best for himself, the community is not best off. It is much worse off than it would have been if each had sacrificed his own welfare for the community good."
So premise (1) of the Closet Utilitarian
Argument is false.