Less Wrong is a community blog devoted to refining the art of human rationality. Please visit our About page for more information.

Comment author: stcredzero 23 July 2013 09:14:20PM 1 point [-]

Conversations seem to occur on several levels simultaneously. There's a level of literal truth. There are also multiple dimensions of politics. (What I call "micro" and "macro," in a way analogous to the application to economics.) There's even a meta-level that consists of just trying to overwhelm people with verbiage.

Comment author: DanielLC 06 July 2013 08:20:55PM 0 points [-]

How unlikely does it need to be to be precluded? The given Scenario A is pretty unlikely.

Comment author: stcredzero 06 July 2013 08:29:13PM 0 points [-]

Well, I note in a comment somewhere, that it would have to be a version of Amelia who was rather ditsy about time.

Comment author: DanielLC 06 July 2013 05:45:59PM 0 points [-]

It doesn't preclude scenario B. It just makes it unlikely. The same could be said about the original scenario A. It's possible that Amelia Bones was mistaken about when she came back, but it's unlikely. The probability is more extreme, but the information is still there.

Comment author: stcredzero 06 July 2013 08:16:42PM 0 points [-]

It doesn't preclude scenario B. It just makes it unlikely.

I have a "Many Worlds/QM" style interpretation of time turner mechanics. Basically, all of the possible interpretations of the information+metainformation you have transmitted via time turner "exists" or is in a kind of superposition, until receiving information precludes them. Making Scenario B overwhelmingly unlikely is precluding it.

Comment author: DanielLC 06 July 2013 04:41:08AM 0 points [-]

How about this:

Scenario A: Amelia Bones comes back from six hours in the future and provides large amounts of evidence of this fact, and of what happens.

Scenario B: Due to quantum randomness, a large number of particles happen to jump into the spot to create a clone of Amelia Bones who believes she is from the future and carries evidence of this.

It is, again, impossible for Dumbledore to tell which of these situations happens. Yet the time turner does not work.

Comment author: stcredzero 06 July 2013 01:50:35PM *  0 points [-]

It's very possible for to distinguish the two situations. The same probabilistic mechanism that determines the arrow of time precludes scenario B. Also, it's not really that Dumbledore is actually doing the distinction. It's more if he could do it.

Comment author: DanielLC 06 July 2013 12:19:46AM 2 points [-]

I don't think you quite get what I'm saying.

You have given two scenarios that Dumbledore cannot distinguish. This proves that he has incomplete information. It does not prove that he has no infomation. That would require that he be unable to distinguish any two scenarios.

Imagine that Amelia Bones tells Dumbledore everything that happened up until her departure from the future, except the path of some neutrino. Furthermore, thanks to Dubledore's legillimancy, he knows she's telling the truth. Can he distinguish between Scenario C, what actually happened, and Scenario C', which is just like C, except that the neutrino went left instead of right?

Is the inability to distinguish C and C' enough for Dumbledore to be able to go back another six hours? If not, how is distinguishing C and C' different from distinguishing A and B?

Comment author: stcredzero 06 July 2013 03:35:16AM *  0 points [-]

No, because if she was able to provide that much information as a conscious communication, she will have provided enough information to have affixed her departure at a specific time.

In any case, there's probably some reason that would make it impossible for her to convey that much information inside 6 hours, anyhow.

Comment author: [deleted] 06 July 2013 01:11:26AM 0 points [-]

I am going to have to accuse you of making a grave Mind Projection.

Physics, to be believable should never talk about "information." I know from study that most of modern physics have this property, and I know EY knows from the QM sequence and the Epistemology 101 sequence.

Special and General Relativity might talk about "observers" and "observables," but these are very distinct from the "information" discussed in Bayesian Stats.

Bayesian stats (i.e. non-omniscient Agents) is the only place you are ever allowed to talk about "information," (Thermodynamics is applying agents to physics).

An observable in relativity is usually taken to mean something you can slap a unit on and call it a day. Mass of bodies, relative velocities, energy, etc.

Comment author: stcredzero 06 July 2013 03:30:41AM 0 points [-]

I am going to have to accuse you of making a grave Mind Projection

Apparently Black Holes preserve information. There are other connections to physics and information theory, Such as the theoretical computers that can use ever smaller quantities of energy, so long as all of their operations are reversible. Given that, it doesn't seem unreasonable that there would be an information theoretic component to the rules of magic. My formulation doesn't require a human mind. If I talk about minds or arbiters, or use language suggesting that then that's just lazy writing on my part.

Comment author: Armok_GoB 05 July 2013 10:39:30PM -1 points [-]

Downvoted for not keeping MOR stuff in the MOR threads.

Comment author: stcredzero 05 July 2013 10:48:23PM 1 point [-]

I only saw the 91-92 thread and didn't think it fit there. Other threads that I found were marked as superseded.

Comment author: TobyBartels 05 July 2013 10:10:57PM 2 points [-]

All information is probabilistic, Bayesian. Two scenarios, A & B, may have identical effects, but if the relevant probability ratios are different, then observing this effect can still give you information. If Amelia Bones tells Dumbledore that she's come from six hours in the future, then his objective Bayesian probability (given the information that he possesses) that she'll survive the next six hours goes up, even though it doesn't rise to 100%. And all information is like this; objective Bayesian probability is never quite 100%.

Comment author: stcredzero 05 July 2013 10:46:51PM 1 point [-]

All information is probabilistic, Bayesian.

Is there a rigorous argument for this, or is this just a very powerful way of modeling the world?

Comment author: linkhyrule5 05 July 2013 10:15:02PM 8 points [-]

The problem here is that even if Scenario A and Scenario B are indistinguishable, Amelia's words still constitute Bayesian evidence on which Dumbledore can update his beliefs.

I'm inclined to believe that whatever intelligence is behind capital-T Time is enforcing an intuitive definition of information, in the same way that brooms work off of Aristotelian mechanics.

Comment author: stcredzero 05 July 2013 10:43:21PM 1 point [-]

The problem here is that even if Scenario A and Scenario B are indistinguishable, Amelia's words still constitute Bayesian evidence on which Dumbledore can update his beliefs.

In my formulation, that's "side information." Really, my gedankenexperiment doesn't work unless Amelia Bones happens to be very ditzy concerning time.

I'm inclined to believe that whatever intelligence is behind capital-T Time is enforcing an intuitive definition of information, in the same way that brooms work off of Aristotelian mechanics.

So then, this is a limitation in the "interface" that the Atlantean engine is following. I think my hypothesis is testable.

Comment author: DanielLC 05 July 2013 09:50:13PM 2 points [-]

Consider Scenario C, in which Amelia Bones travels back in time, does not have additional information about it, and tells Dumbledore. This is distinguishable from Scenarios A and B, and this possibility is eliminated. It still conveys some information. All you've shown is that Dumbledore did not have all the information. There are still two possible scenarios. This would be true if he was told about everything except the path of a single neutrino. If that's all that's necessary to keep time turners from breaking, how could they have possibly figured out they break?

Comment author: stcredzero 05 July 2013 09:53:52PM 0 points [-]

I don't think the path of a single neutrino could do it. Answer this, from the informational POV of Dumbledore's location in space-time, is path P of that neutrino any less consistent with Scenario A or Scenario B?

View more: Next