The talk about uncertainty is indeed a red herring. There are two things going on here:
A linear aggregative (or fast-growing enough in the relevant range) social welfare function makes even small probabilities of existential risk more important than large costs or benefits today. This is the Bostrom astronomical waste point. Weitzmann just uses a peculiar model (with agents with bizarre preferences that assign infinite disutility to death, and a strangely constricted probability distribution over outcomes) to indirectly introduce this. You can reject it with a bounded social welfare function like Manzi or Nordhaus, representing your limited willingness to sacrifice for future generations.
The fact that there are many existential risks competing for our attention, and many routes to affecting existential risk, so that spending effort on any particular risk now means not spending that effort on other existential risks, or keeping it around while new knowledge accumulates, etc. Does the x-risk reduction from climate change mitigation beat the reduction from asteroid defense or lobbying for arms control treaties at the current margin? Weitzmann addresses this by saying that the risk from surprise catastrophic climate change is much higher than other existential risks collectively, which I don’t find plausible.
The talk about uncertainty is indeed a red herring. There are two things going on here:
A linear aggregative (or fast-growing enough in the relevant range) social welfare function makes even small probabilities of existential risk more important than large costs or benefits today. This is the Bostrom astronomical waste point. Weitzmann just uses a peculiar model (with agents with bizarre preferences that assign infinite disutility to death, and a strangely constricted probability distribution over outcomes) to indirectly introduce this. You can reject it with a bounded social welfare function like Manzi or Nordhaus, representing your limited willingness to sacrifice for future generations.
The fact that there are many existential risks competing for our attention, and many routes to affecting existential risk, so that spending effort on any particular risk now means not spending that effort on other existential risks, or keeping it around while new knowledge accumulates, etc. Does the x-risk reduction from climate change mitigation beat the reduction from asteroid defense or lobbying for arms control treaties at the current margin? Weitzmann addresses this by saying that the risk from surprise catastrophic climate change is much higher than other existential risks collectively, which I don’t find plausible.