In the context of assessing interventions with very uncertain cost-effectiveness (in my view, practically any context), in which sense would it matter a lot whether one uses sharp or unsharp probabilities? With sharp probabilities, it would be close to arbitrary which interventions should be supported. With unsharp probabilities, it would be indeterminate which interventions should be supported, but one would still end up supporting something based on some criteria.
One thing is whoever does not reject UNSHARP might not have severely imprecise credences about everything. I might believe that
intervention 1 has severely indeterminate but astronomically high (positive or negative) EV.
intervention 2 seems overall good, although it has lower EV.
Then, I’d probably prioritize intervention 2. If I instead endorsed SHARP, I might favor intervention 1 (because of a sufficient 51% credence 1 is good). (I’m actually not sure about this, though. One could argue that 1 and 2 remain incomparable and that I have no reason to favor 2 over 1.)
Another thing, assuming there is no 2-like intervention, is that the criterion to pick could be something other than “act straightforwardly as if you were endorsing SHARP”. It could instead be, e.g., some (other) form of bracketing.
One could argue that 1 and 2 remain incomparable and that I have no reason to favor 2 over 1.
If the absolute value of the expected cost-effectiveness of 1 was astronomically larger than that of intervention 2, I think comparing the interventions would be similar to comparing intervention 1 with one with cost-effectiveness of 0 (burning money). It is very unclear whether the expected cost-effectiveness of 1 is positive or negative. So it would be close to arbitrary which intervention has the highest expected cost-effectiveness.
Another thing, assuming there is no 2-like intervention, is that the criterion to pick could be something other than “act straightforwardly as if you were endorsing SHARP”. It could instead be some (other) form of bracketing.
One thing is whoever does not reject UNSHARP might not have severely imprecise credences about everything. I might believe that
intervention 1 has severely indeterminate but astronomically high (positive or negative) EV.
intervention 2 seems overall good, although it has lower EV.
Then, I’d probably prioritize intervention 2. If I instead endorsed SHARP, I might favor intervention 1 (because of a sufficient 51% credence 1 is good). (I’m actually not sure about this, though. One could argue that 1 and 2 remain incomparable and that I have no reason to favor 2 over 1.)
Another thing, assuming there is no 2-like intervention, is that the criterion to pick could be something other than “act straightforwardly as if you were endorsing SHARP”. It could instead be, e.g., some (other) form of bracketing.
If the absolute value of the expected cost-effectiveness of 1 was astronomically larger than that of intervention 2, I think comparing the interventions would be similar to comparing intervention 1 with one with cost-effectiveness of 0 (burning money). It is very unclear whether the expected cost-effectiveness of 1 is positive or negative. So it would be close to arbitrary which intervention has the highest expected cost-effectiveness.
Bracketing departs from impartiality, and I find this very unappealing.