Everybody Wants to Rule the Future: Is Longtermism's Mandate of Heaven by Arithmetic Justified?
I was reading David Kinney's interesting work from 2022 "Longtermism and Computational Complexity" in which he argues that longtermist effective altruism is not action-guiding because calculating the expected utility of events in the far future is computationally intractable.
In this paper I want to show that even if we could magically solve Kinney's inference problem (a genie gives us perfect probability distributions over every possible future) we can't make definitive expected value comparisons between many longtermist strategies because it is an undecidable problem.