On 22 Nov 2012, at 22:45, John Clark wrote:

On Thu, Nov 22, 2012 at 11:15 AM, Bruno Marchal <marc...@ulb.ac.be> wrote:

>>John Clark keeps saying that after the duplication John Clark will be in both places.

> Not from its personal subjective view (1p).

Pronouns are Bruno Marchal's crutch and now "it" joins the pantheon.

>> Where subjectivity is concerned if things are identical from a third person perspective they are certainly identical from any first party one. If you think I'm wrong give me a counterexample.

> They are not identical. One body is reconstituted in W, and the other in M.

Position is a very poor way to establish personal identity,


UDA has been build so that we can understand how the laws of physics amerge from arithmetic (or anything Turing complete) without the notion of personal identity. I have already explain this, so comment my earlier explanation of this. You introduce unnecessary difficulties. All you need is being clear on step 1, that is the fact that you survive in the usual sense (like you can survive a travel by plane, or the drinking coffee experience) in the case of simple (without duplication) teleportation experience (and you have already accept this in some post).




you'd become a different person every time you take a walk, or the Earth rotates on its axes.

You keep contradicting points on which we have already agree. The H- man survives the duplication, in both M and W. You can note the "and", as this is said from a third party pov. Then the step 3 point is that both the M-man and the W-man were not able to predict before (in H) which of M and W they would personally confirmed.




In fact how do you even know what position you or your copy are in?

By using a gps, or by asking someone on the street, or simply by recognizing the city. Given the protocol, that is enough.




If you instantly exchange the position of you and a identical copy of you inside identical rooms in Washington and Moscow neither you nor the copy will notice the slightest difference.

The question asked in Helsinki concerns the result of the future self- localization, that is after they open the boxes. So they would be aware of the permutation you describe.



And an outside observer will not notice a difference either. The very universe itself will not notice that any exchange has occurred! Objectively it makes no difference and subjectively it makes no difference. If the difference is not objective and the difference is not subjective then that rather narrows down your options in pointing out just where that difference is.

Ever hear of The Identity Of Indiscernibles? The philosopher who discovered it was Leibniz about 1690. He said that things that you can measure are what's important, and if there is no way to find a difference between two things then they are identical and switching the position of the objects does not change the physical state of the system. Leibniz's idea turned out to be very practical, although until the 20th century nobody realized it, before that his idea had no observable consequences because nobody could find two things that were exactly alike. Things changed dramatically when it was discovered that atoms have no scratches on them to tell them apart. By using The Identity Of Indiscernibles you can deduce one of the foundations of modern physics the fact that there must be two classes of particles, bosons like photons and fermions like electrons, and from there you can deduce The Pauli Exclusion Principle, and that is the basis of the periodic table of elements, and that is the basis of chemistry, and that is the basis of life. If The Identity Of Indiscernibles is wrong then this entire chain breaks down and you can throw Science into the trash can.

I repeat: the question is asked to the H-man, when he is in H, before he pushes on the button, and it concerns the result of the future opening of the box. In H he knows that it will be either W, or M, but not both as comp will prevent the existence of instantaneous telepathy between the two copies.




> So you agree now that the situation is equivalent, with respect to probability, for QM and comp?

Comp is your thing not mine and I have no idea if its equivalent to QM.

Comp is your thing, as illustrated by your reply to Craig. Then what I say follow from a bit of reflexion.




>>Until one duplicate sees Moscow and the other duplicate does not the two brains produce first person experiences that neither a third party nor the first party itself can distinguish between; and if there is only one thing it's nonsensical to ask "which one?" about anything.

>Again, what you say is obvious, and non relevant.

Not relevant?! There are 2 cities and if there are all identical then there is only one Bruno Marchal regardless of how many brains and bodies of his are around, so it's meaningless to ask the question "which one will see Washington?" because there is nothing to choose from, at that point there is only one. Now it is possible that the environment of Washington will change one of those copies into the Washington man and that man will be the one the environment of Washington changes. What else do you expect to say about it?

That your own reasoning here asses the P(W) = 1/2.




> he question is asked to the H-man, about which city he will see

 Pronouns are Bruno Marchal's crutch.

He = the H-mans. You can interview the two copies.



> 1) In Helsinki you are put under anesthesia, then sent to W or to M, according to a random coin choice. You wake up in a room, open the door and see that you are in a city. 2) same protocol as in step 3, except that the annihilation is done when you are under anesthesia.

I don't remember what step 3 is,


It is the subject of the thread. Please print the paper and the slide in front of you.
http://iridia.ulb.ac.be/~marchal/publications/SANE2004MARCHALAbstract.html




and if we're talking about what things will be like after something was annihilated I don't see how it matters if it was done under anesthesia or not,

Well, it might be useful to assess clearly, as you have done in many post, if you get the definition of comp, step 1 and step 2. (although step 2 is used only in step 4).




>The very fact that you are doing remark like that show that you agenda is just being negative about me,

I have nothing against you and seem a nice enough fellow, but you did say "the notion of Löbian machine is completely standard" and that is not true.

The notion is completely standard. The name is not.
All recursively enumerable extensions of PA or ZF are Löbian, notably.



> If you got the 3-Ed right, you might have got the 3-view on the 1- Ed right, but not their personal 1-view on those 1-view, as they are unique.

Ah this explains everything, you believe in the soul and the duplicating chamber can duplicate anything except for the soul. I don't.

Comp entails trivially that, in a duplication experience, your subjective view is not duplicated from the 1p pov. From that pov, it remains one and entire, from its own points of view, and is duplicated only from the 3-pov. This is sum up by "the person does not feel the split". Factually, once finding himself in W (say), he knows only that there is a copy in M from his belief in the protocol, unlike his direct apprehension of which city he find itself right now.




>>> "W" represents "the first person experience
>> Who's first person experience?
>Of the guy opening the door and seeing W.

Oh you mean the guy who is turned into the the Washington man by the environment.

You can phrase it like that (although it is a bit misleading). the environment do nothing. It is the duplication machine which makes the body in the two places, and it is the first person view which select which one it is. Everything is deterministic in the 3p description, and non deterministic in the account described in any diaries (the 1- p).


And you want to know who that guy is.

This is never asked. The candidate is all the person described in the experience (from the 3p view). But those experience are felt to be unique, so that after the duplication, although both the W-man and the M-man are still both the H-man, they feel different, and both got one bit of information (W, or M).



Well he's the guy who was turned into the the Washington man by the environment and before that he was the guy who was not turned into the the Washington man by the environment. I don't know how you expect to get more specific than that.

OK, but this does not answer the question asked. you are still denying the obvious fact that both the W-man, and the M-man were unable to predict in Helsinki which of Washington and Moscow they would feel to be in after pushing on the button.

Bruno

http://iridia.ulb.ac.be/~marchal/



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