Correct me if I'm wrong, but pre-commitment isn't an option in Newcomb's problem, so the best, the most rational, the winning decision is two-boxing.

By construction, Omega's predictions are known to be essentially infallible. Given that, whatever you choose, you can safely assume Omega will have correctly predicted that choice. To what extent, then, is pre-commitment distinguishable from deciding on the spot?

In a sense there is an implicit pre-commitment in the structure of the problem; while you have not pre-committed to a choice on this specific problem, you are essentially pre-committed to a decision-making algorithm.

Eliezer's argument, if I understand it, is that any decision-making algorithm that results in two-boxing is by definition irrational due to giving a predictably bad outcome.

Of course the one-boxers get more money: They were put in a situation in which they could either get $1 000 000 or $1 001 000, whereas the two-boxers were put in a situation in which they could get $0 or $1000.

It makes no sense to compare the two decisions the way you and Eliezer do. It's like organizing a swimming competition between an Olympic athlete who has to swim ten kilometers to win and an untrained fatass who only has to swim a hundred meters to win, and concluding that because the fatass wins more often than the athlete, therefore fatasses clearly make better swimmers than athletes.

Please ... Newcomb is a toy non-mathematizable problem and not a valid argument for anything at all. There must be a better example, or the entire problem is invalid.

"Winning" and "being right" are different concepts. That is the point of distinguishing between epistemic and instrumental rationality.

I'm not sure how you can implement an admonition to Win and not just to (truly, sincerely) try. What is the empirical difference?

I suppose you could use an expected regret measure (that is, the difference between the ideal result and the result of the decision summed across the distribution of probable futures) instead of an expected utility measure.

Expected regret tends to produce more robust strategies than expected utility. For instance, in Newcomb's problem, we could say that two-boxing comes from expected utility but one-boxing comes from regret-minimizing (since a "failed" two-box gives $1,000,000-$1,000=$999,000 of regret, if you believe Omega would have acted differently if you had been the type of person to one-box, where a "failed" one-box gives $1000-$0=$1,000 of regret).

Using more robust strategies may be a way to more consistently Win, though perhaps the true goal should be to know when to use expected utility and when to use expected regret (and therefore to take advantage both of potential bonanzas and of risk-limiting mechanisms).

You're assuming it does no damage to oneself to break one's own promises. Virtue theorists would disagree.

Breaking one's promises damages one's integrity - whether you consider that a trait of character or merely a valuable fact about yourself, you will lose something by breaking your promise even if you never see the fellow again.

This assumes no one can ever find out you didn't pay, as well. In general, though, it seems better to assume everything will eventually be found out by everyone. This seems like enough, by itself, to keep promises and avoid most lies.

Thank you, I too was curious.

We need names for these positions; I'd use hyper-rationalist but I think that's slightly different. Perhaps a consequentialist does whatever has the maximum expected utility at any given moment, and a meta-consequentialist is a machine built by a consequentialist which is expected to achieve the maximum overall utility at least in part through being trustworthy to keep commitments a pure consequentialist would not be able to keep.

I guess I'm not sure why people are so interested in this class of problems. If you substitute Clippy for my lift, and up the stakes to a billion lives lost later in return for two billion saved now, there you have a problem, but when it's human beings on a human scale there are good ordinary consequentialist reasons to honour such bargains, and those reasons are enough for the driver to trust my commitment. Does anyone really anticipate a version of this situation arising in which only a meta-consequentialist wins, and if so can you describe it?

Thank you, I too was curious.

We need names for these positions; I'd use hyper-rationalist but I think that's slightly different. Perhaps a consequentialist does whatever has the maximum expected utility at any given moment, and a meta-consequentialist is a machine built by a consequentialist which is expected to achieve the maximum overall utility at least in part through being trustworthy to keep commitments a pure consequentialist would not be able to keep.

I guess I'm not sure why people are so interested in this class of problems. If you substitute Clippy for my lift, and up the stakes to a billion lives lost later in return for two billion saved now, there you have a problem, but when it's human beings on a human scale there are good ordinary consequentialist reasons to honour such bargains, and those reasons are enough for the driver to trust my commitment. Does anyone really anticipate a version of this situation arising in which only a meta-consequentialist wins, and if so can you describe it?

If one defines rationality in some way that isn't about winning, your example shows that rationalists-in-such-a-sense might not win.

If one defines rationality as actually winning, your example shows that there are things that even Omega cannot do because they involve logical contradiction.

If one defines rationality as something like "expected winning given one's model of the universe" (for quibbles, see below), your example shows that you can't coherently carry around a model of the universe that includes a superbeing who deliberately acts so as to invalidate that model.

I find all three of these things rather unsurprising.

The traditional form of Newcomb's problem doesn't involve a superbeing deliberately acting so as to invalidate your model of the universe. That seems like a big enough difference from your version to invalidate inferences of the form "there's no such thing as acting rationally in grobstein's version of Newcomb's problem; therefore it doesn't make sense to use any version of Newcomb's problem in forming one's ideas about what constitutes acting rationally".

I think the third definition is pretty much what Eliezer is getting at when he declares that rationalists/rationality should win. Tightening it up a bit, I think we get something like this: rationality is a strategy S such that at each moment, acting as S tells you to act -- given (1) your beliefs about the universe at that point and (2) your intention of following S at all times -- maximizes your net utility (calculated in whatever way you prefer; that is mostly not a question of rationality). This isn't quite a definition, because there might turn out to be multiple such strategies, especially for people whose initial beliefs about the universe are sufficiently crazy. But if you add some condition to the effect that S and your initial beliefs shouldn't be too unlike what's generally considered (respectively) rational and right now, there might well be a unique solution to the equations. And it seems to me that what your example shows about this definition is simply that you can't consistently expect Omega to act in a way that falsifies your beliefs and/or invalidates your strategies for acting. Which is (to me) not surprising, and not a reason for defining rationality in this sort of way.