which has some as-of-yet unspecified implication for the merit of his position
See Furcas's comment.
that allows him to see his life as no different from any others and yet still act in preference to himself
I never said it was no different. Elsewhere in the thread, I had argued that selfishness is entirely compatible with biting the third bullet. Egan's Law.
And it was obvious what distinction he was making by using the words "very roughly the same reason" instead of "exactly the same reason".
I disagree; if it had been obvious, I wouldn't have had to point it out explicitly. Maybe the cognitive history would help? I had originally typed "the same reason," but added "very roughly" before posting because I anticipated your objection. I think the original was slightly funnier, but I thought it was worth trading off a little of the humor value in exchange for making the statement more defensible when taken literally.
I'm sorry, but that's just not "how it works". [...] your full explanation [looks] blatantly ad hoc.
I'm curious. If what actually happened looks ad hoc to you, what's your alternative theory? If you don't trust what I say about what I was thinking, then what do you believe instead? You seem to think I've committed some error other than writing two admittedly somewhat opaque comments, but I'm not sure what it's supposed to be.
Right, so of course I'm rather selfish in the sense of valuing things-like-myself, and so of course I buy more things for myself than I do for random strangers, and so forth. But I also know that I'm not ontologically fundamental; I'm just a conjunction of traits that can be shared by other observers to various degrees. So "I don't throw myself off cliffs for very roughly the same reason I don't throw other people off cliffs" is this humorously terse and indirect way of saying that identity is a scalar, not a binary attribute. (Notice that I said "very roughly the same reason" and not "exactly the same reason"; that was intentional.)
I was trying to be cute.
I would say that the ordinarily very useful abstraction of subjective probability breaks down in situations that involve copying and remerging people, and that our intuitive morality breaks down when it has to deal with measure of experience. In the current technological regime, this isn't a problem at all, because the only branching we do is quantum branching, and there we have this neat correspondence between quantum measure and subjective probability, so you can plan for "your own" future in the ordinary obvious way. How you plan for "your own" future in situations where you expect to be copied and merged depends on the details of your preferences about measure of experience. For myself, I don't know how I would go about forming such preferences, because I don't understand consciousness.
But all the resulting observers who see the coin come up tails aren't you. You just specified that they weren't. Who cares what they think?
I don't throw myself off cliffs for very roughly the same reason I don't throw other people off cliffs.
Following Nominull and Furcas, I bite the third bullet without qualms for the perfectly ordinary obvious reasons. Once we know how much of what kinds of experiences will occur at different times, there's nothing left to be confused about. Subjective selfishness is still coherent because you're not just an arbitrary observer with no distinguishing characteristics at all; you're a very specific bundle of personality traits, memories, tendencies of thought, and so forth. Subjective selfishness corresponds to only caring about this one highly specific bundle: only caring about whether someone falls off a cliff if this person identifies as such-and-such and has such-and-these specific memories and such-and-those personality traits: however close a correspondence you need to match whatever you define as personal identity.
The popular concepts of altruism and selfishness weren't designed for people who understand materialism. Once you realize this, you can just recast whatever it was you were already trying to do in terms of preferences over histories of the universe. It all adds up to, &c., &c.
I count 6+ comments from others on meta-talk, 8+ down-mods, and 0 [sic] explanations for the errors in my solution. Nice work, guys.
If it is in fact the case that your complaints are legitimately judged a negative contribution, then you should expect to be downvoted and criticized on those particular comments, regardless of whether or not your solution is correct. There's nothing contradictory about simultaneously believing both that your proposed solution is correct, and that your subsequent complaints are a negative contribution.
I don't feel like taking the time to look over your solution. Maybe it's perfect. Wonderful! Spectacular! This world becomes a little brighter every time someone solves a math problem. But could you please, please consider toning down the hostility just a bit? These swipes at other commenters' competence and integrity are really unpleasant to read.
ADDENDUM: Re tone, consider the difference between "I wonder why this was downvoted, could someone please explain?" (which is polite) and "What a crock," followed by shaming a counterfactual Wei Dai (which is rude).
On reflection, I'm actually going to start spelling my first name again.