Caring about possible people in far Worlds

In your existential multiversal angst, have you noticed your confusion?

You keep worrying about untestables and treating progressively more horrible mental constructs as if they were in any sense real. Basically, you behave like a medieval peasant believing every Brothers Grimm-type story anyone tells them. You Pascal-mug yourself by privileging a few scary tales out of an uncountable amount of possible ones.

This line of thinking is the real LW Basilisk, not the tame Roko's type. Posts like that is the worst of the worst of Less Wrong, and I blame Eliezer for pushing his pet untestable, the MWI, which is what started the whole nonsense.

EDIT: apparently I misunderstood the post, the author was not suffering from the many-worlds angst, but rather trying to elucidate that it does not make sense to do so.

I care about possible people. My child, if I ever have one, is one of them, and it seems monstrous not to care about one's children.

I think you may have found one of the quickest ways to tempt me into downvoting a post without reading further (it wasn't quite successful - I read all the way through before downvoting). Poor reasoning and stereotypical appeal to emotion are probably not the ideal opener.

Beyond that, you never made clear what the purpose of the following arguments is and gave them really confusing titles.

• I'm not sure in what way argument 1 shows the multiverse to be "Sadistic", or what position I am supposed to have held for it to be relevant to me. I guess if I cared about all hypothetical people, you may have showed that there is some subset of them I can't affect?
• I'm going to assume by "obtains" you mean "occurs". With that in mind, I still have trouble understanding how this is relevant to anything. I guess you take "X-Risk" as an example of "generally accepted bad thing", and that any bad thing would work? As far as I can tell, this line of reasoning doesn't actually lead to paralysis, as if you can't affect the non-actual worlds, obviously you can safely make all your decisions while disregarding them. On the other hand, if you think there is some way you think you can "break out" and affect all the other worlds, you may be motivated to attempt it at nearly any cost, but I don't see this as problematic (assuming you have "solved" Pascal's Mugging). Also, while I haven't read Bostrom's paper, I'm pretty sure infinity-related paralyses hardly ever occur if you just use surreal numbers (for example).
• I basically don't understand the third argument. You mention worlds 1, 2, 3 without explaining what the relationship is between them. I'm also not sure what you mean by "the morally relevant thing" being "qualitative" (and possible not sure what you mean by "quantifiable"). I am also not sure in what way the conclusion is different from argument 1 (there are things we can't affect that ideally we'd want to affect).

Short version: it's confusing and unclear/not relevant to my beliefs (which is fine, if it's relevant to the beliefs of someone on here at least)/really confusing/terrible opener.

what matters

To whom?

BTW, following Gary Drescher in Good and Real, I think of “real” as an indexical, i.e. something is real if it's causally connected with the speaker, or with something that's causally connected with the speaker, or with something that's causally connected with something that's causally connected with the speaker, etc. And as far as I can introspect, I only care about things that are real in this sense.

Reality fluid, or existiness, is a ratio rather than an absolute value in roughly the same sense that weight is a ratio, defined relative to kilograms or pounds or daltons. If weight was a morally relevant thing, and we didn't know the conversion factor between kilograms and daltons, this would cause practical problems, but not philosophical ones.

So I think the "reality-fluid can't be all that's left" argument fails at P3.4 - we would be able to distinguish the two cases if we knew the ratio of reality fluid between World1 and World2.

Edit: This post is an argument against the conjunctive truth of two things, Many Worlds, and the way in which we think of What Matters. It seems that the most natural interpretation of it is that Many Worlds is true, and thus my argument is against our notion of What Matters. In fact my position lies more in the opposite side - our notion of What Matters is (strongly related to) What Matters, so Many Worlds are less likely.

Downvoted based on your edit. Your preferences have no bearing on how the multiverse is, one way or another. Setting up a dichotomy like this is a mistake. To the extent that you care about physics and metaphysical theories you should instead work out how to describe your preferences in such models in a way that adds up to normal.

Concern about the inevitable suffering and death of potential people is the foundation of antinatalism., not included (or perhaps not included under its name) in your survey. I am not here arguing for or against antinatalism, but antinatalism belongs front and center in any survey of the inevitable suffering and death of potential people. Antinatalism is the claim it is morally wrong to bring new life into being because that new life will inevitably suffer and die.