It’s because I’m not intending the trajectories to be a measure of all value in the universe, only the value we affect through our choices. When humanity goes extinct, it no longer contributes intrinsic value through its own flourishing and it has no further choices which could have instrumental value, so you might expect its ongoing value to be zero. And it would be on many measures.
Setting up the measures so that it goes to zero at that point also greatly simplifies the analysis, and we need all the simplification we can get if we want to get a grasp on the value of the longterm future. (Note that this isn’t saying we should ignore effects of our actions on others, just that if there is a formal way of setting things up that recommends the same actions but is more analytically tractable, we should use that.)
It’s because I’m not intending the trajectories to be a measure of all value in the universe, only the value we affect through our choices. When humanity goes extinct, it no longer contributes intrinsic value through its own flourishing and it has no further choices which could have instrumental value, so you might expect its ongoing value to be zero. And it would be on many measures.
Setting up the measures so that it goes to zero at that point also greatly simplifies the analysis, and we need all the simplification we can get if we want to get a grasp on the value of the longterm future. (Note that this isn’t saying we should ignore effects of our actions on others, just that if there is a formal way of setting things up that recommends the same actions but is more analytically tractable, we should use that.)