NP-Complete Problems and Physical Reality (2005) • Hacker News Board

Re: NP-Complete Problems and Physical Reality (2005)

#31

Post by adrianN » Tue, Jul 14, 2015, 6:37 PM UTC

andyjohnson0 wrote: post #26

kordless wrote: post #24

Earlier quoted context omitted.

I'm leaning toward the parallel universe hypothesis as well, except I'm thinking it's more like there are part-time processes that run in parallel, do their work, then exit after they come to some type of consensus of state. It would end up looking something like a bunch of containers running a game on your computer, processing all the other player's moves, arriving at consensus, sending that consensus to a central '…

If the multiverse / physical reality has a "global central thing" then it has a scaling bottleneck, and we have a problem.

We wouldn't really notice if the simulation keeps getting slower though.

Re: NP-Complete Problems and Physical Reality (2005)

#32

Post by Lawtonfogle » Tue, Jul 14, 2015, 8:54 PM UTC

andyjohnson0 wrote: post #22

javajosh wrote: post #20

Earlier quoted context omitted.

How is killing yourself a correct solution to anything, and what is "n" in your equation? Humans are experience integrators with the rather interesting (and unique) opportunity to "emit" the useful integrations that make it easier (or possible) for others to perform a similar integration. We do it on a personal level with children and friends; and on an impersonal level with books and papers.

I'm not sure if you read the paper. Aaronson writes: "given a formula ϕ, guess a random assignment x, then kill yourself if x does not satisfy ϕ." In other words, the only universes in which you find yourself existing (alive) are ones in which you are in possession of a solution to ϕ, which you obtained easily by guessing. Its a not-entirely-serious riff on the Anthropic Principle [1] and maybe the "Quantum Suicide"…

The problem (well, one of them) is that there is no guaranteed way of killing yourself. For any sufficiently complex problem you will end up being more likely to near fatally maim yourself in the attempt to kill yourself for an incorrect guess than you will be to make a correct guess.

Re: NP-Complete Problems and Physical Reality (2005)

#33

Post by Houshalter » Wed, Jul 15, 2015, 12:10 AM UTC

FeepingCreature wrote: post #5

On the point of anthropic computing: it is important to note that you have not accomplished any _improvement_ to your condition by killing yourself; before as after, you had found a correct solution with probability 2^-n. Anthropic computing is just "fancy guessing". What is interesting about it to me is that the "true computational nature of reality" must be such that sufficient computation is available for you to r…

You squeeze your probability mass into universes where the problem is solved, and therefore you are more likely to find yourself existing in those universes. What this means for your actual experience, is that as soon as you turn the quantum suicide machine on, you should expect to see it output a correct answer and not kill you. You can never observe the machine output an incorrect answer, nor can you observe your own death.

>Which does make it strange that quantum physics does not seem to give us any way to "get at" all this computation that must be going on behind the scenes.

Why should it?

Also if parallel worlds can interact with each other and aren't entirely separate, then we probably wouldn't exist. The first parallel world to develop a way of taking over other parallel universes would win. The optimal self replicator that can spread through all universes would take over everything.

Re: NP-Complete Problems and Physical Reality (2005)

#34

Post by kordless » Sun, Jul 19, 2015, 3:42 AM UTC

andyjohnson0 wrote: post #26

kordless wrote: post #24

Earlier quoted context omitted.

I'm leaning toward the parallel universe hypothesis as well, except I'm thinking it's more like there are part-time processes that run in parallel, do their work, then exit after they come to some type of consensus of state. It would end up looking something like a bunch of containers running a game on your computer, processing all the other player's moves, arriving at consensus, sending that consensus to a central '…

If the multiverse / physical reality has a "global central thing" then it has a scaling bottleneck, and we have a problem.

Not if that exists on another level of abstraction. Limits here would be good. There, not so much assumed.