Thanks for the post and the response David, that helpfully clarifies where you are coming from. What I was trying to get at is that if you want to say that strong longtermism isn't the correct conclusion for an impartial altruist who wants to know what to do with their resources, then that would call for more argument as to where the strong longtermist's mistake lies or where the uncertainty should be. On the other hand, it would be perfectly possible to say that the impartial altruist should end up endorsing strong longtermism, while recognising that you yourself are not entirely impartial (and have done with the issue). Personally I also think that strong longtermism relies on very debatable grounds, and I would also put some uncertainty on the claim "the impartial altruist should be a strong longtermist"- the tricky and interesting thing is working out where we disagree with the longtermist.
(also I recognise as you said that this post is not supposed to be a final word on all these problems, I'm just pointing to where the inquiry could go next).
On the second part of your response, I think that depends on what motivates you and what your general worldview is. I don't believe in objective moral facts, but I also generally see the world as a place where each and all could do better. For some that helps motivate action, for some it causes angst- I don't think there is a correct view there.
Separately I do actually worry that strong longtermism only works for consequentialists (though you don't have to believe in objective morality). The recent paper attempts to make the foundations more robust but the work there is still in its infancy. I guess we will see where it goes.
Just to second this because it seems to be a really common mistake- Greaves and MacAskill stress in the strong longtermism paper that the aim is to advance an argument about what someone should do with their impartial altruistic budget (of time or resources), not to tell anyone how large that budget should be in the first place.
Also- I think the author would be able to avoid what they see as a "non-rigorous" decision to weight the short-term and long-term the same by reconceptualising the uneasiness around longtermism dominating their actions as an uneasiness with their totally impartial budget taking up more space in their life. I think everyone I have talked to about this feels a pull to support present day people and problems alongside the future, so it might help to just bracket off the present day section of your commitments away from the totally impartial side, especially if the argument against the longtermist conclusion is that it precludes other things you care about. No one can live an entirely impartial life and we should recognise that, but this doesn't necessarily mean that the arguments for the rightness of doing so are wrong.
Thanks for writing this, I'm reading a lot of critiques of longtermism at the moment and this is a very interesting one.
Apart from the problems that you raise with expected value reasoning about future events, you also question the lack of pure time preference in the Greaves-MacAskill paper. You make a few different points here, some of which could co-exist with longtermism and some couldn't. I was wondering how much of your disagreement might be meaningfully recast as a differing opinion on how large your impartial altruistic budget should be, as an individual or as a society?
I think this might be helpful because you say things like: "While longtermism says we should be thinking primarily about the far-future consequences of our actions (which is generally taken to be on the scale of millions or billions of years), strong longtermism says this is the only thing we should think about." This is slightly misleading because the paper stresses that strong longtermism is only true of your genuinely impartial altruistic resources, therefore even on the section on deontic strong longtermism, there is no claim about what we should exclusively care about. (This seems uber nitpicky but I think it is consequential- though the authors of the paper may have stronger views on the ideal size of impartial altruistic budgets, they are very careful not to tie strong longtermism to the truth of those far less rigourously defined arguments).
However, a belief that we should be biased towards the present (such as you say you hold) could be understood as shrinking the amount of your time and resources you think should be spent on impartial causes at all, and consequently also on longtermist causes.
To disambiguate, your other claim that "We should prefer good things to happen sooner, because that might help us to bring these good things about" could plausibly bear on how we should use our impartial resources, as an instrumental reason for acting as if we were partial towards the present. There isn't an argument in your essay for this but it could be an interesting lever to push on because it would disagree with longtermism more directly.
Thanks! I read this a while back and I remember it was great, but I haven't yet looked with an eye to taxonomising its arguments. Could be a useful exercise.
Thanks a lot!