jimrandomh comments on Problematic Problems for TDT - Less Wrong

36 Post author: drnickbone 29 May 2012 03:41PM

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Comment author: APMason 23 May 2012 02:39:16PM 6 points [-]

Hmm, so TDT-prime would reason something like, "The TDT simulation will one-box because, not knowing that it's the simulation, but also knowing that the simulation will use exactly the same decision theory as itself, it will conclude that the simulation will do the same thing as itself and so one-boxing is the best option. However, I'm different to the TDT-simulation, and therefore I can safely two-box without affecting its decision." In which case, does it matter how inconsequential the difference is? Yep, I'm confused.

Comment author: drnickbone 23 May 2012 03:34:34PM 2 points [-]

I also had thoughts along these lines - variants of TDT could logically separate themselves, so that T-0 one-boxes when it is simulated, but T-1 has proven that T-0 will one-box, and hence T-1 two-boxes when T-0 is the sim.

But a couple of difficulties arise. The first is that if TDT variants can logically separate from each other (i.e. can prove that their decisions aren't linked) then they won't co-operate with each other in Prisoner's Dilemma. We could end up with a bunch of CliqueBots that only co-operate with their exact clones, which is not ideal.

The second difficulty is that for each specific TDT variant, one with algorithm T' say, there will be a specific problematic problem on which T' will do worse than CDT (and indeed worse than all the other variants of TDT) - this is the problem with T' being the exact algorithm running in the sim. So we still don't get the - desirable - property that there is some sensible decision theory called TDT that is optimal across fair problems.

The best suggestion I've heard so far is that we try to adjust the definition of "fairness", so that these problematic problems also count as "unfair". I'm open to proposals on that one...

Comment author: jimrandomh 23 May 2012 08:14:02PM 0 points [-]

The right place to introduce the separation is not in between TDT and TDT-prime, but in between TDT-prime's output and TDT-prime's decision. If its output is a strategy, rather than a number of boxes, then that strategy can include a byte-by-byte comparison; and if TDT and TDT-prime both do it that way, then they both win as much as possible.

Comment author: dlthomas 23 May 2012 08:25:17PM 1 point [-]

But doesn't that make cliquebots, in general?

Comment author: drnickbone 24 May 2012 12:08:43PM 0 points [-]

I'm thinking hard about this one...

Can all the TDT variants adopt a common strategy, but with different execution results, depending on source-code self-inspection and sim-inspection? Can that approach really work in general without creating CliqueBots? Don't know yet without detailed analysis.

Another issue is that Omega is not obliged to reveal the source-code of the sim; it could instead provide some information about the method used to generate / filter the sim code (e.g. a distribution the sim was drawn from) and still lead to a well-defined problem. Each TDT variant would not then know whether it was the sim.

I'm aiming for a follow-up article addressing this strategy (among others).

Comment author: khafra 24 May 2012 05:57:56PM 0 points [-]

Can all the TDT variants adopt a common strategy, but with different execution results, depending on source-code self-inspection and sim-inspection?

This sounds equivalent to asking "can a turing machine generate non-deterministically random numbers?" Unless you're thinking about coding TDT agents one at a time and setting some constant differently in each one.