Is the potential astronomical waste in our universe too small to care about?

If Moral Parliament can make deals, it could as well decide on a single goal to be followed thereafter, at which point moral uncertainty is resolved (at least formally). For this to be a good idea, the resulting goal has to be sensitive to facts discovered in the future. This should also hold for other deals, so it seems to me that unconditional redistribution of resources in not the kind of deal that a Moral Parliament should make. Some unconditional redistributions of resources are better than others, but even better are conditional deals that say where the resources will go depending on what is discovered in the future. And while resources could be wasted, so that at a future point you won't be able to direct at much in a new direction, seats in the Moral Parliament can't be.

Another possible conclusion is that the "moral parliament" model either doesn't match how you actually think, or doesn't match how you "should" think.

Regarding your question, I don't see theoretical reasons why one shouldn't be making deals like that (assuming one can and would stick to them etc). I'm not sure which decision theory to apply to them though.

The Moral Parliament idea generally has a problem regarding time. If it is thought of as making decisions for the next action (or other bounded time period), with new distribution of votes etc when the next choice comes up, then there are intertemporal swaps (and thus pareto improvements according to each theory) that it won't be able to achieve. This is pretty bad, as it at least appears to be getting pareto dominated by another method. However, if it is making one decision for all time over all policies for resolving future decisions, then (1) it is even harder to apply in real life than it looked, and (2) it doesn't seem to be able to deal with cases where you learn more about ethics (i.e. update your credence function over moral theories) -- at least not without quite a bit of extra explanation about how that works. I suppose the best answer may well be that the policies over which the representatives are arguing include branches dealing with all ways the credences could change, weighted by their probabilities. This is even more messy.

My guess is that of these two broad options (decide one bounded decision vs decide everything all at once) the latter is better. But either way it is a bit less intuitive than it first appears.

What's the argument against doing the UDT thing here?

Wei, insofar as you are making the deal with yourself consider that in the world in which it turns out that the universe could support doing at least 3^^^3 ops you may not be physically capable of changing yourself to work more toward longtermist goals than you would otherwise. (I.e. Human nature is such that making huge sacrifices to your standard of living and quality of life negatively effects your ability to work productively on longtermist goals for years.) If this is the case, then the deal won't work since one part of you can't uphold the bargain. So in the world in which it turns out that the universe can support only 10^120 ops you should not devote less effort to longtermism than you would otherwise, despite being physically capable of devoting less effort.

In a related kind of deal, both parts of you may be capable of upholding the deal, in which case I think such deals may be valid. But it seems to me that you don't need UDT-like reasoning and the deal future to believe that your future self with better knowledge of the size of the cosmic endowment ought to change his behavior in the same way as implied by the deal argument. Example: If you're a philanthropist with a plan to spend $X of your wealth on shortermist philanthropy and $X on longtermist-philanthropy when you're initially uncertain about the size of the cosmic endowment because you think this is optimal given your current beliefs and uncertainty, then when you later find out that the universe can support 3^^^3 ops I think this should cause you to shift how you spend your $2X to give more toward longtermist philanthropy just because the longtermist philanthropic opportunities now just seem more valuable. Similarly, if you find out that the universe can only support 10^120, then you ought to update to giving more toward short-termist philanthropy.

So is there really a case for UDT-like reasoning plus hypothetical deals our past selves could have made with themselves suggesting that we ought to behave differently than more common reasoning suggests we ought to behave when we learn new things about the world? I don't see it.

Claim: There are some deals you should make but can't.

Although this is fighting the hypothetical, I think that the universe is almost certainly infinite because observers such as myself will be much more common in infinite than finite universes. Plus, as I'm sure you realize, the non-zero probability that the universe can support an infinite number of computations means that the expected number of computations we expect to be performed in our universe is infinite.

As Bostrom has written, if the universe is infinite then it might be that nothing we do matters so perhaps your argument is correct but with the wrong sign.