Indeed. Pareto optimality is a necessary condition for an “ideal” society. Economists often make the mistake of thinking pareto optimality is a sufficient condition for this, which it is not: it’s pareto optimal if I have everything and don’t much want to part with any of it.
What sort of situation are you thinking of where X would be better than Y for one person and worse for none, but Y better than X all things considered?
I think of the concept of Pareto optimality as being useless because the path between the initial allocation, and a really good allocation, is usually littered with Pareto-optimums that must be broken through to get to the really good allocation. The really-good allocation is itself presumably Pareto-optimal. But you shouldn’t get into the habit of thinking that’s worth much.
Would you agree that a worthwhile concept of optimality would imply that there are no Pareto improvements that can be made to an optimum? (Though the optimum may not be Pareto superior to all alternatives.)
Pareto optimums are probably not very good optimums, in any domain. They’re just tractable. An example of looking for your keys under the streetlamp.
Pareto optima aren’t very good on average, but shouldn’t any worthwhile concept of optimality imply Pareto optimality?
Indeed. Pareto optimality is a necessary condition for an “ideal” society. Economists often make the mistake of thinking pareto optimality is a sufficient condition for this, which it is not: it’s pareto optimal if I have everything and don’t much want to part with any of it.
Not if more than a dozen people are involved. Certainly not if a million people are involved.
EDIT: Oops. Wrong.
What sort of situation are you thinking of where X would be better than Y for one person and worse for none, but Y better than X all things considered?
Doh! You’re right.
I think of the concept of Pareto optimality as being useless because the path between the initial allocation, and a really good allocation, is usually littered with Pareto-optimums that must be broken through to get to the really good allocation. The really-good allocation is itself presumably Pareto-optimal. But you shouldn’t get into the habit of thinking that’s worth much.
Would you agree that a worthwhile concept of optimality would imply that there are no Pareto improvements that can be made to an optimum? (Though the optimum may not be Pareto superior to all alternatives.)
Yes, within the assumptions of the Pareto model.