Possible misconception: “Greaves and MacAskill say we can ignore short-term effects. That means longtermists will never reduce current suffering. This seems repugnant.”
‘This seems repugnant’ doesn’t seem like a justifiable objection to me, so not something an advocate of SLT should be obliged to take on directly.
If I said “this doctor’s theory of liver deterioration suggests that I should reduce my alcohol intake, which seems repugnant to me”, you would not feel compelled to respond that “actually, some of the things the doctor is advocating could allow you to drink more alcohol”.
(I suspect that beyond the “this seems repugnant” there is a more coherent critique—and that is the critique we should focus on.)
However, it is worth noting that it is possible that longtermists may end up reducing suffering today as a by-product of trying to improve the far future.
It might be worth re-stating this. Thinking about objective functions and constraints, either
R1. SLT implies that resources should be devoted in a way that does less to reduce current suffering (i.e., implies more current suffering than absent SLT) or
R2. SLT does not change our objective function, or it coincidentally implies an allocation that does has no differential effect on current suffering (a ‘measure zero’, i.e., coincidental result)
R3. SLT implies that resources should be devoted in a way that leads to less current suffering
R3 seems unlikely to be the case, particularly if we imagine bounds on altruistic capacity. And, if there were an approach that could use the same resources to reduce current suffering even more, it already should have been chosen in the absence of SLT.
If R2 is the case then SLT is not important for our resource decision so we can ignore it.
If R1 holds (which seems most likely to me), then following SLT does imply an increase in current suffering, and we are back to the main objection
‘This seems repugnant’ doesn’t seem like a justifiable objection to me, so not something an advocate of SLT should be obliged to take on directly.
If I said “this doctor’s theory of liver deterioration suggests that I should reduce my alcohol intake, which seems repugnant to me”, you would not feel compelled to respond that “actually, some of the things the doctor is advocating could allow you to drink more alcohol”.
(I suspect that beyond the “this seems repugnant” there is a more coherent critique—and that is the critique we should focus on.)
In response, you stated:
It might be worth re-stating this. Thinking about objective functions and constraints, either
R1. SLT implies that resources should be devoted in a way that does less to reduce current suffering (i.e., implies more current suffering than absent SLT) or
R2. SLT does not change our objective function, or it coincidentally implies an allocation that does has no differential effect on current suffering (a ‘measure zero’, i.e., coincidental result)
R3. SLT implies that resources should be devoted in a way that leads to less current suffering
R3 seems unlikely to be the case, particularly if we imagine bounds on altruistic capacity. And, if there were an approach that could use the same resources to reduce current suffering even more, it already should have been chosen in the absence of SLT.
If R2 is the case then SLT is not important for our resource decision so we can ignore it.
If R1 holds (which seems most likely to me), then following SLT does imply an increase in current suffering, and we are back to the main objection