I'm not reading 127 comments, but as a newcomer who's been invited to read this page, along with barely a dozen others, as an introduction, I don't want to leave this unanswered, even though what I have to say has probably already been said.

First of all, the answer to Newcomb's Problem depends a lot on precisely what the problem is. I have seen versions that posit time travel, and therefore backwards causality. In that case, it's quite reasonable to take only one box, because your decision to do so does have a causal effect on the amount in Box B. Presumably causal decision theorists would agree.

However, in any version of the problem where there is no clear evidence of violations of currently known physics and where the money has been placed by Omega before my decisions, I am a two-boxer. Yet I think that your post above must not be talking about the same problem that I am thinking of, especially at the end. Although you never said so, it seems to me that you must be talking about a problem which says "If you choose Box B, then it will have a million dollars; if you choose both boxes, then Box B will be empty.". But that is simply not what the facts will be if Omega has made the decision in the past and currently understood physics applies. In the problem as stated, Omega may make mistakes in the future, and that makes all the difference.

It's presumptuous of me to assume that you're talking about a different problem from the one that you stated, I know. But as I read the psychological states that you suggest that I might have —that I might wish that I considered one-boxing rational, for example—, they seem utterly insane. Why would I wish such a thing? What does it have to do with anything? The only thing that I can wish for is that Omega has predicted that I will be a one-boxer, which has nothing to do with what I consider rational now.

The quotation from Joyce explains it well, up until the end, where poor phrasing may have confused you. The last sentence should read:

When Rachel wishes she was Irene's type she is wishing for Irene's circumstances, not wishing to make Irene's choice.

It is simply not true that Rachel envies Irene's choice. Rachel envies Irene's situation, the situation where there is a million dollars in Box B. And if Rachel were in that situation, then she would still take both boxes! (At least if I understand Joyce correctly.)

Possibly one thing that distinguishes me from one-boxers, and maybe even most two-boxers, is that I understand fundamental physics rather thoroughly and my prior has a very strong presumption against backwards causality. The mere fact that Omega has made successful predictions about Newcomb's Paradox will never be enough to overrule that. Even being superintelligent and coming from another galaxy is not enough, although things change if Omega (known to be superintelligent and honest) claims to be a time-traveller. Perhaps for some one-boxers, and even for some irrational two-boxers, Omega's past success at prediction is good evidence for backwards causality, but not for me.

So suppose that somebody puts two boxes down before me, presents convincing evidence for the situation as you stated it above (but no more), and goes away. Then I will simply take all of the money that this person has given me: both boxes. Before I open them, I will hope that they predicted that I will choose only one. After I open them, if I find Box B empty, then I will wish that they had predicted that I would choose only one. But I will not wish that I had chosen only one. And I certainly will not hope, beforehand, that I will choose only one and yet nevertheless choose two; that would indeed be irrational!