All of Decius's Comments + Replies

We can't tell we're in the all-zero universe by examining any finite number of bits.

What does it mean for the all-zero universe to be infinite, as opposed to not being infinite? Finite universes have a finite number of bits of information describing them (This doesn't actually negate the point that uncomputable utility functions exist, merely that utility functions that care whether they are in a mostly-empty vs perfectly empty universe are a weak example.


These preferences are required to be coherent with breaking things up into sums, so
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2Abram Demski4y
Ultimately, I am advocating a logical-induction like treatment of this kind of thing. * Initial values are based on a kind of "prior" -- a distribution of money across traders. * Values are initially inconsistent (indeed, they're always somewhat inconsistent), but, become more consistent over time as a result of traders correcting inconsistencies. The traders who are better at this get more money, while the chronically inconsistent traders lose money and eventually don't have influence any more. * Evidence of all sorts can come into the system, at any time. The system might suddenly get information about the utility of some hypothetical example, or a logical proposition about utility, whatever. It can be arbitrarily difficult to connect this evidence to practical cases. However, the traders work to reduce inconsistencies throughout the whole system, and therefore, evidence gets propagated more or less as well as it can be.
2Abram Demski4y
What it means here is precisely that it is described by an infinite number of bits -- specifically, an infinite number of zeros! Granted, we could try to reorganize the way we describe the universe so that we have a short code for that world, rather than an infinitely long one. This becomes a fairly subtle issue. I will say a couple of things: First, it seems to me like the reductionist may want to object to such a reorganization. In the reductive view, it is important that there is a special description of the universe, in which we have isolated the actual basic facts of reality -- things resembling particle position and momentum, or what-have-you. Second, I challenge you to propose a description language which (a) makes the procrastination example computable, (b) maps all worlds onto a description, and (c) does not create any invalid input tapes. For example, I can make a modified universe-description in which the first bit is '1' if the button ever gets pressed. The rest of the description remains as before, placing a '1' at time-steps when the button is pressed (but offset by one place, to allow for the extra initial bit). So seeing '0' right away tells me I'm in the button-never-pressed world; it now has a 1-bit description, rather than an infinite-bit description. HOWEVER, this description language includes a description which does not correspond to any world, and is therefore invalid: the string which starts with '1' but then contains only zeros forever. This issue has a variety of potential replies/implications -- I'm not saying the situation is clear. I didn't get into this kind of thing in the post because it seems like there are just too many things to say about it, with no totally clear path.