I don’t have time to look into this in full depth, but it looks like a good paper, making useful good-faith critiques, which I very much appreciate. Note that the paper is principally arguing against ‘strong longtermism’ and doesn’t necessarily disagree with longtermism. For the record, I don’t endorse strong longtermism either, and I think that the paper delineating it which came out before any defenses of (non-strong) longtermism has been bad for the ability to have conversations about the form of the view that is much more widely endorsed by ‘longtermists’.
My main response to the points in the paper would be by analogy to cosmopolitanism (or to environmentalism or animal welfare). We are saying that something (the lives of people in of future generations) matters a great deal more than most people think (at least judging by their actions). In all cases, this does mean that adding a new priority will mean a reduction in resources going to existing priorities. But that doesn’t mean these expansions of the moral circle are in error. I worry that the lines of argument in this paper apply just as well to denying previous steps like cosmopolitanism (caring deeply about people’s lives across national borders). e.g. here is the final set of bullets you listed with minor revisions:
Human biases and limitations in moral thinking lead to distorted and unreliable judgments, making it difficult to meaningfully care about
the far futuredistant countries.Our moral concern is naturally limited to those close to us, and our capacity for empathy and care is finite. Even if we care about
future generationspeople in distant countries in principle, our resources are constrained.Focusing on
the far futuredistant countries comes at a cost to addressingpresent-daylocal needs and crises, such as health issues and poverty.Implementing
longtermismcosmopolitanism would require radical changes to human psychology or to social institutions, which is a major practical hurdle.
What I’m trying to show here is that these arguments apply just as well to argue against previous moral circle expansions which most moral philosophers would think were major points of progress in moral thinking. So I think they are suspect, and that the argument would instead need to address things that are distinctive about longtermism, such as arguing positively that future peoples’ lives don’t matter morally as much as present people.
We can make meaningful decisions about how to help people in the distant future. For example, to allow them to exist at all, to allow them to exist with a complex civilisation that hasn’t collapsed, to give them more prosperity that they can use as they choose, to avoid destroying their environment, to avoid collapsing their options by other irreversible choices, etc. Basically, to aim and giving them things near the base of Maslow’s Hierarchy of Needs or to give them universal goods — resources or options that can be traded for whatever it is they know they need at the time. And the same is often true for international aid.
In both cases, it isn’t always easy to know that our actions will actually secure these basic needs, rather than making things worse in some way. But it is possible. One way to do it for the distant future is to avoid catastrophes that have predictable longterm effects, which is a major reason I focus on that and suggest others do too.
I don’t see it as an objection to Longtermism if it recommends the same things as traditional morality — that is just as much a problem for traditional theories, by symmetry. It is especially not a problem when traditional theories might (if their adherents were careful) recommend much more focus on existential risks but in fact almost always neglect the issue substantially. If they admit that Longtermists are right that these are the biggest issues of our time and that the world should massively scale up focus and resources on them, and that they weren’t saying this before we came along, then that is a big win for Longtermism. If they don’t think it is all that important actually, then we disagree and the theory is quite distinctive in practice. Either way the distinctiveness objection also fails.