It seems to me that it’s not right to assume the probability of opportunities to trade are zero?
Suppose both John and David are alive on a desert island right now (but slowly dying), and there’s a chance that a rescue boat will arrive that will save only one of them, leaving the other to die. What would they contract to? Assuming no altruistic preferences, presumably neither would agree to only the other person being rescued.
It seems more likely here that bargaining will break down, and one of them will kill off the other, resulting in an arbitrary resolution of who ends up on the rescue boat, not a “rational” resolution.
Doesn’t irreversibility imply that there is zero probability of a trade opportunity to reverse the thing? I’m not proposing a new trait that your original scenario didn’t have; I’m proposing that I identified which aspect of your scenario was load-bearing.
I don’t think I understand how your new hypothetical is meant to be related to anything discussed so far. As described, the group doesn’t have strongly incomplete preferences, just 2 mutually-exclusive objectives.
Zero probability of trade is indeed the feature which would make the argument in the OP potentially not go through, when irreversibility is present. (Though we would still get a weakened form of the argument from the OP, in which we complete the preferences by adding a preference for a trade which has zero probability, and the original system is indifferent between that completion and its original preferences.)
It seems to me that it’s not right to assume the probability of opportunities to trade are zero?
Suppose both John and David are alive on a desert island right now (but slowly dying), and there’s a chance that a rescue boat will arrive that will save only one of them, leaving the other to die. What would they contract to? Assuming no altruistic preferences, presumably neither would agree to only the other person being rescued.
It seems more likely here that bargaining will break down, and one of them will kill off the other, resulting in an arbitrary resolution of who ends up on the rescue boat, not a “rational” resolution.
Doesn’t irreversibility imply that there is zero probability of a trade opportunity to reverse the thing? I’m not proposing a new trait that your original scenario didn’t have; I’m proposing that I identified which aspect of your scenario was load-bearing.
I don’t think I understand how your new hypothetical is meant to be related to anything discussed so far. As described, the group doesn’t have strongly incomplete preferences, just 2 mutually-exclusive objectives.
Zero probability of trade is indeed the feature which would make the argument in the OP potentially not go through, when irreversibility is present. (Though we would still get a weakened form of the argument from the OP, in which we complete the preferences by adding a preference for a trade which has zero probability, and the original system is indifferent between that completion and its original preferences.)