MugaSofer comments on Problematic Problems for TDT - Less Wrong

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

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Comments (298)

You are viewing a single comment's thread. Show more comments above.

Comment author: MugaSofer 25 December 2012 04:13:32PM -1 points [-]

However, if Alice and Bob play the prisoner's dilemma against each other, the situation is much closer to symmetric. Alice faces a player identical to itself except with the "Alice" comment replaced with "Bob", and Bob faces a player identical to itself except with the "Bob" comment replaced with "Alice". Hopefully, their algorithm would compress this information down to "The other player is identical to me, but has a comment difference in its source code", at which point each player would be in an identical situation.

Why doesn't that happen when dealing with Omega?

Comment author: AlexMennen 25 December 2012 08:01:22PM 0 points [-]

Because if Omega uses Alice's source code, then Alice sees that the source code of the simulation is exactly the same as hers, whereas Bob sees that there is a comment difference, so the situation is not symmetric.

Comment author: MugaSofer 25 December 2012 10:21:11PM -1 points [-]

So why doesn't that happen in the prisoner's dilemma?

Comment author: AlexMennen 25 December 2012 10:47:57PM 0 points [-]

Because Alice sees that Bob's source code is the same as hers except for a comment difference, and Bob sees that Alice's source code is the same as his except for a comment difference, so the situation is symmetric.

Comment author: MugaSofer 26 December 2012 01:32:52AM -1 points [-]

Newcomb:

Bob sees that there is a comment difference, so the situation is not symmetric.

Prisoner's Dilemma:

Bob sees that Alice's source code is the same as his except for a comment difference, so the situation is symmetric.

Do you see the contradiction here?

Comment author: AlexMennen 26 December 2012 01:59:23AM *  0 points [-]

Newcomb, Alice: The simulation's source code and available information is literally exactly the same as Alice's, so if Alice 2-boxes, the simulation will too. There's no way around it. So Alice one-boxes.

Newcomb, Bob: The simulation was in the situation described above. Bob thus predicts that it will one-box. Bob himself is in an entirely different situation, since he can see a source code difference, so if he two-boxes, it does not logically imply that the simulation will two-box. So Bob two-boxes and the simulation one-boxes.

Prisoner's Dilemma: Alice sees Bob's source code, and summarizes it as "identical to me except for a different comment". Bob sees Alice's source code, and summarizes it as "identical to me except for a different comment". Both Alice and Bob run the same algorithm, and they now have the same input, so they must produce the same result. They figure this out, and cooperate.

Comment author: MugaSofer 26 December 2012 02:15:28AM *  -1 points [-]

Ignore Alice's perspective for a second. Why is Bob acting differently? He's seeing the same code both times.

Comment author: AlexMennen 26 December 2012 02:21:57AM 0 points [-]

Don't ignore Alice's perspective. Bob knows what Alice's perspective is, so since there is a difference in Alice's perspective, there is by extension a difference in Bob's perspective.

Comment author: MugaSofer 26 December 2012 02:25:33AM -1 points [-]

Bob looks at the same code both times. In the PD, he treats it as identical to his own. In NP, he treats it as different. Why?

Comment author: AlexMennen 26 December 2012 02:31:59AM *  0 points [-]

The source code that Bob is looking at is the same in each case, but the source code that [the source code that Bob is looking at] is looking at is different in the two situations.

NP: Bob is looking at Alice, who is looking at Alice, who is looking at Alice, ...

PD: Bob is looking at Alice, who is looking at Bob, who is looking at Alice, ...

Clarifying edit: In both cases, Bob concludes that the source code he is looking at is functionally equivalent to his own. But in NP, Bob treats the input to the program he is looking at as different from his input, whereas in PD, Bob treats the input to the program he is looking at as functionally equivalent to his input.