Is death bad?

Interesting points. I agree that the arguments against non-person-affecting views are rather compelling, but still find arguments against person-affecting views even more persuasive. Person-affecting views can easily endorse extinction if it's going to occur when almost everyone currently alive has died anyway - for example, if there is a meteorite 150 years away from destroying the earth and we could easily avert it but would need to raise taxes by 1% to do so, I think most person-affecting views would say to let it hit (assuming it's a secret meteorite, etc).

There's also a second way in which they endorse extinction. Almost nobody can stomach the claim that it's morally neural to create people who you know will be tortured for their whole lives; therefore, person-affecting views often end up endorsing an asymmetry where it's bad to create people with net-negative lives but neutral to create people with net-positive lives. But unless you predict an incredibly utopian future, that's an argument for human extinction right now - since there will otherwise be enough net-negative people in the future to outweigh the interests of everyone currently alive.

I agree that it's weird to think of saving a life as equivalent to creating one, but can we actually defend saving a life as being more important in general? Most basic case: either you can save a 20 year old who will live another 60 years, or else have a child who will live 60 years total. You say that the former is better because it avoids nonconsensual termination. But it doesn't! The 20 year old still dies eventually... Of course, in the latter case you have two nonconsensual deaths not one, but there's an easy fix for that: just raise the child so it's won't be scared of death! I know that sounds stupid but it's sort of what I was getting at when I claimed that some arguments about death are circular: they only apply to people who already think that death is bad. In fact it seems like most people are pretty comfortable with the thought of dying, so raising the child that way wouldn't even be unusual. Under that view, the only reason that death is morally bad is the fact we don't consent to it, and so convincing people not to fear death is just as good for the world as actually making them immortal.

I agree that this is a slightly weird conflict within my own ethical system. The reason that I brought it up here is that this particular conflict follows from a few seemingly plausible claims about marginal value of lives, plus the standard LessWrong beliefs that death (for an individual) and extinction (for our species) are both very bad things. I'm curious whether this is an implicit tension in many people's views, or whether somebody has found an adequate solution which I'm not yet aware of.

Agreed that the specifics matter, but since it's futile to make detailed predictions about those, I'm assuming the simplest case which is for the ageing process to be slowed overall, including in brain cells. (A longevity treatment which left your body healthy but your mind gone wouldn't really deserve the name.) I'm wondering what you're specifically thinking of, though. If, for example, cognitive decline occurred along the same progression that it currently does, but a constant factor more slowly, how would that impact the calculations?

If I remember correctly, Eliezer has a preference for living a very long time, even if literal infinity turns out to be impossible in our universe's physics. (Until the stars go out, etc.) Living for a very long time, for example on a scale of thousands or millions of years, is not impossible in principle. Of course it may require changes to human body on many levels (repairing cells, increasing brain capacity), but that kind of goes automatically with transhumanism.

My understanding is that "good" literally is (coherently extrapolated) human preference. But human preference is not completely arbitrary, because it was shaped by evolution. I would expect that most intelligence species shaped by evolution would e.g. in general prefer life over death, or pleasure over pain. Some other values may reflect our biological path; for example the preference for friendship or love -- I can imagine that for e.g. a superintelligent spider, a universe where everyone hates everyone but for purely game-theoretical reasons the major players still cooperate to achieve win/win outcomes, could seem perfectly "good".