On 11 Mar 2012, at 06:33, John Clark wrote:

On Sat, Mar 10, 2012 at 3:29 AM, Bruno Marchal <marc...@ulb.ac.be> wrote:

> and it is just very simple, for all people up to now, that the 1- views on their own 1-view is not duplicated.

Well, if you haven't before considered the possibility that this "obvious" common sense assumption could be dead wrong it is certainly high time you did!

It simply cannot. Comp would be violated in case the diary contains a "feeling split experience". The guy can believe he is split, because he knows the protocol and trust the machinery and the people handling it. At no point he can know, by personal experience, that he is split. That information will not appear in any diary. We use the same common sense as the one used to grasp addition and multiplication.

Yes, the assumption that the 1-views on their own 1-view can not be duplicated is indeed simple, very very very simple, but not simple in a good way. Theories should be as simple as possible, but not simpler, because then they just become stupid.

Sure. But here, the theory is comp. The fact that the 1-view are not duplicated, from their own 1-view pov, can be justified by the fact that the read-cut-reconstitution are not part of the experience. Like the reconstitution delay in step 2, those events does not impact on the brain processing (given that by assumption we reconstitute the person at the right substitution level from the relevant instantaneous state description of the brain. It is literally trivial.

I insist that in my symmetrical room experiment there can be (or at least should not be) any doubt that the person's 1-views on their own 1-view HAS IN FACT BEEN DUPLICATED.

1) You said yourself there is only one consciousness in that case.
2) you confuse the 1-view on the 1-view on the 1-view with the 3-view on the 1-view on the 1-view. You really avoid putting yourself in the place of one of those reconstituted person. But you have to be able to do that for any of them. When we consider the 1-view pov, we have to stick with it, and not get out in any 3p view, which miss the point of the initial question. With any 3p view, there are no indeterminacy, we already know that, with comp, but the question bears on the next 1-view, which feels to be unique by the trivial argument above. 3) Let us come back to the original thought experience. The indeterminacy appears when they "open the door" of the reconstitution boxes, which is a deterministic event from the 3p view, but can't be deterministic from the 1p-views.

> but they feel like not having been duplicated

Yes that is the entire point, you could be a copy of Bruno Marchal, you could be only 5 minutes old, I could have used generic atoms and information on how to assemble them from the original Bruno Marchal, so now you feel just like Bruno Marchal and your memories of being a child are just as vivid as the memories the original Bruno Marchal has.


> they know only intellectually the possible existence of the other

That is quite untrue, both you (the copy) and you (the original Bruno Marchal) are in that symmetrical room and can see each other plain as day, and until random quantum fluctuations become significant it will be as if you're looking in a mirror for both of "you", the two of "you" will both see somebody who looks just like Bruno Marchal who is moving and speaking in synchronization with the way "you" move and speak.

I don't assume QM. The point is that when opening the door (in the initial thought experiment), they break the symmetry and have each a personal different experiences, which they were unable to predict before opening the door.

>> and in my symmetrical room thought experiment I make it crystal clear that the first person personal subjective perspective CAN be duplicated just like everything else can be.

> Crystal clear?

Yes crystal clear, as clear as the azure sky of deepest summer.

If the 1-views have been duplicated, then their are identical, (before they open the door this makes sense). But then there is only one 1- view, as you said yourself. But then this means that the 3-duplication has not entailed a duplication of the 1-views. And this is confirmed when they open the door, the 1-views are entire and unique in front of an non expectable location.

> It only shows that the 1-view is duplicated from a 3-view pov, not from the 1-view perspective.

Explain to me how the 1-view perspective of anybody has changed from any perspective you care to name, any at all. Before the switch you, from your first person perspective, consciously feel like you are looking at somebody who looks, moves, acts, and speaks exactly like you do, it's as if you're looking into a mirror;

Without the vertical symmetry. If my face is not symmetrical, I might not recognize myself (like in the novel "despair" by Nabokov). But this is only distracting from the issue.

and after the switch you, from your first person perspective consciously feel like you are looking at somebody who looks, moves, acts, and speaks exactly like you do, it's as if you're looking into a mirror. What has changed from the original's point of view, what has changed from the copy's point of view, what has changed from a third person observer's point of view, what has changed from the universe's point of view? Absolutely positively nothing. To win this argument all you have to do is explain to me how instantly changing the position of 2 identical objects changes anything from anyone's or anything's point of view. You can't.

Indeed, but this makes my point. The 1-view at this stage is unique. We might fuse them, and nothing would have happened.

For the other: note that if the reconstitution boxes are different from inside, in W and in M, then the candidate copies, in the two boxes, can still not know where they have been reconstituted, but can know that they have been reconstituted and so have different consciousness. No more fusing is possible, without introducing some amnesia, and this means the consciousness has already differentiated. This is something which has to be taken into account for the measure problem.

Note also, for John, that in that case, if the guy in Helsinki is not told that the box are different or not, he cannot know if his consciousness has differentiated or not. If he is told in advance that the boxes are different (from inside again), then he knows that he has differentiated once he look around him inside the reconstitution box, and that he is definitely in W or in M, but does not know which one. Then the 1-indeterminacy follows from the PUP principle (PUP = Post-posed Uncertainty Principle: if today I can predict that tomorrow I will be uncertain of the outcome of an experience I will do, then I am today uncertain about the outcome of that experience that I will do tomorrow).

It seems to me this clears the point completely. I address your points below, though. David is right, it is a bit of sequence of straw men, or of avoiding the reasoning.

> The 1-view attributed by an outsider, not the 1-view from its own pov. You continue to talk like if that was the same thing.

That's because it IS the same thing,

But, then, by definition of the 1-view, there is only *one* of them, from the 1-view point. This makes sense when the inside of the Reconstitution-boxes are identical. It makes no sense if they are different, or when he opens the door, the outcome of which we are interested in. The proba is asked for the self-localization result that they get when opening the door, when the differentiation/split occurred (or not, if the box are different from inside). You stop the thought experiment before its completion.

you are no better at determining when you and your double exchange positions than a outside third party observer is. Objectively or subjectively and first second third or ANY point of view, no person, no God, no thing, NOTHING can tell that anything has happened when 2 identical things instantly exchange positions. A person's 1-views on their own 1-view CAN IN FACT BE DUPLICATED.

You just said that the 1-view are the same, but by definition of 1- view, being the same makes it not having been duplicated, and when going out of the box, they will feel not having been duplicated. So the difference will break the symmetry for deterministic reason, and that leads to the first person indeterminacy. Indeed you say that the experience is the same before the differentiation, so this confirms and even explains why they cannot predict the outcome of what they will see when opening the box.

And why should this fact really be so surprising, information can be duplicated and there is no difference between one hydrogen atom and another, so where's the problem? But of course I know what the problem is, the conclusion is odd, not illogical, not self contradictory, just odd. Well there is no law of physics or logic that says reality can't be odd.

Indeed. And the conclusion is that the 1-views cannot know if they will see W or M when deciding to go outside, that is the result of the differentiation brought by the fact that they are 1-identical (as you said yourself) and 3-different (because their bodies are in two different cities). See above for an alternative explanation which does not use the fact that they have identical consciousness in the boxes, and which show directly the non relevance of your symmetrical thought experience. It is enough to assume that the reconstitution boxes are not identical from inside (for example one is green and the other is blue).

>> Information was not annihilated, matter was not annihilated, energy was not annihilated, so just what was "annihilated" in Helsinki?

> Its body.

But the Helsinki man's body still exists, only now it's in Moscow and Washington,

I can show you the ashes of the guy who was in Helsinki (straw man).

but people travel all the time without apparent loss of personal identity.

> If your prefer, the local information which was available in Helsinki is erased after having been read and sent to W and to M.

No it has not, both the Washington and Moscow man remember being the Helsinki man just fine, no information has been lost; true neither of them continues to receive sensory information from Helsinki, but the same would be true if the Helsinki man had just gotten on a jet for Moscow.

True but irrelevant. Jet does not duplicate bodies (straw man).

>> you don't need elaborate thought experiments involving duplicating chambers to realize that you can never know for sure what you will see when you open a door, surprises are always possible.

> We are in the course of a reasoning. As you illustrate, nothing is obvious


> so in this case we have to explain why this particular form of "surprise" is guarantied by the comp hypothesis.

But there is nothing unique about comp in that, the existence of surprise is guarantied by ANY hypothesis including the God hypothesis.

Determinism entails indeterminacy in the hypothesis via self- duplicabilty, only. That's the point. The surprise that you seem to agree with is the 1-indeterminacy.

It also shows that mechanism entails the logical *necessity* of that indeterminacy, which is new and different from the deterministic chaos, and a priori different from the QM indeterminacy. yet strikingly similar in Everett QM.

If that point was obvious, Einstein would have just said to Bohr that it is enough to abandon the collapse postulate, and Everett would not have made his MW thesis.

Also, it is plainly false that the existence of surprise is guarantied by ANY hypothesis. Think about the hypothesis that there is no surprise (actually sometimes made by believer in determinism).

> If the prediction is "I will see Flying Circus", then [...]

Then the entire thought experiment is pointless. You're supposed to be illustrating the subtle and non-obvious nature of "I",

Not at all. Those are simple, and have even been formalized. But we don't need that to get the reversal result (only to get some embryo of physics from arithmetic).

UDA uses simple partial definition of the 3-I and 1-I notions, and it makes the 1-indeterminacy rather easy to grasp I think, once you do properly the thought experience, inclduing putting yourself at the place of the copies.

but when you throw around that personal pronoun with abandon as if its meaning was already perfectly clear and even use it right at the start as a premise in the thought experiment then there is no way you can learn anything about the nature of "I" from it;

The 1-I is well defined by the owner of the diary of memory. The 3-I is well defined by the shape of the body, for the outsider of the teleportation boxes. The personal identity issue is out of the topic, but we can come back on it later if interested.

it's like a definition that includes the word you want defined, it's circular and not helpful.

This is already the case for any notion of self-duplication. It can be 100% handled formally by the use of the "Dx = xx" diagonalization stuff (or Kleene's second recursion theorem). There are no problem of circularity.

Yet, this formal stuff is not needed to understand the indeterminacy issue. You just seem to avoid this issue, by avoiding the moment they open the door (or the case where the boxes are different from inside). See above.

>> If his brain was in Washington but all his external stimuli came from Moscow then he'd be identical to the Moscow guy, that is to say he'd be the Moscow guy. Except when things are very far apart and signal transmission time becomes a factor the position of the brain is not important.

>You add something which is just not relevant for the point into consideration. We assume the protocol is given to the guy in Helsinki, and that he trust the protocol and that the protocol is rigorously followed. You are changing the experiment.

I am changing nothing. This experiment is supposed to tell us something about consciousness not about Helsinki, the ONLY difference between the Helsinki man and the Moscow man is that the Moscow man now gets his external stimuli from Moscow instead of Helsinki, that's it, nothing more; and that could have happened through your duplicating chamber scenario or through a virtual reality telepresence setup, or the Helsinki man could have simply gotten on a jet for Moscow, it all amounts to the same thing as far as consciousness is concerned.

You forget the guy in Washington!  (straw man).

So all this "first person indeterminacy" stuff really means is "you never know what you will see next", and I didn't need a exotic duplicating chamber to figure that out.

What you say is not relevant. In the case without duplication, I know what I will see next. So the precise indeterminacy I talk about is provided by the self-duplication fact. This is needed to be acknowledged to get the next step.

You behave like some people who want my argument being not interesting. You are oscillating between "delirious nonsense" and "completely trivial". A bit like my "political" opponents, BTW.

> The point is that they were not able to predict in advance the precise localization where they feel now (after the duplication and opening the door).

Or to say the exact same thing with different words, you never know what you will see when you open a door.

This generalization does not follow and is contradicted in the simple (non duplicating) teleportation protocol. Of course, they are even easier counter-example: when I open my door at home, I usually know what I will see. (Straw man again).

Well it's true but I just don't see how it's very profound.

Because to see this you have to follow the next steps of the reasoning. By definition of proof, we cut the reasoning in little *simple* (not profound) piece. To be sure some people consider that 1-indeterminacy as being very profound, because it is very simple and shows what most people did not expect: 3-determinacy implies 1-indeterminacy.
But being profound or not is not relevant for the issue.

> the probability question bears on the self-localization result after they open the door.

If the question "where is your consciousness located?" ...

That is not the question. The question is "which city will I see when opening the door?".

.... has any meaning at all (and it probably does not) then the answer is the location of your eyes ears nose tongue and hands, the location of your brain is irrelevant unless its so far away that signal transmission time becomes significant. Actually although I would not like it myself a consciousness could exist with no external stimuli whatsoever, in which case asking where it is located would be like asking where the number eleven is located.

I agree with you on all this, but it is not relevant for the issue.

> You were just not answering the question asked.

I've tried, I promise you I've really really tried, but its hard because most of the questions make no damn sense.

Then comp has no sense.
If you believe in comp, then it has sense, because the experience can be done in principle. You are in Helsinki, you push on a button, and you know in advance that whatever you will feel to live will be "I see W" or "I see M".

If you deny this, then all question about surviving any operation is made senseless, and, to talk like you, only philosophers discussing on the nets could defend that idea.

> In the W-M duplication experience, you can predict with certainty (assuming comp) that 1) you will feel to survive, and you will survive as one integral, entire, non duplicated person,

And that is obviously false, you can be duplicated and for all you know you already are a duplicated person,

(What you say is fuzzy, but can make sense in the comp theory, and indeed will have some sense after step seven). I don't see here anything showing false the 1-indeterminacy. If the refutation is here, you have to elaborate a lot.

and if your point one is false there is no point in reading your other 4 points that build on that.

I totally agree with this.

(Note that this point is point three, though). If you have a problem with step 1 or step 2, please tell us.

> OK? Can we move on to step 4?

Not if its foundation is built on the assumption that this silly 1- view indeterminacy and n-person perspective stuff is true or even coherent;

What is incoherent, and what is false?
I can only suspect that you miss the part where you have to put yourself in the place of each duplicated people, and see how they can perceive the situation from their conscious-first-person perspective.

a proof is only as strong as its weakest link


and that link is not only weak its nonexistent.

Nonexistent? You lost me.

Let me ask you a question. You are told in Helsinki that you (your body) will be "read-and-cut" and the information is sent (again) to W and M, where your body, or bodies, is (are) reconstituted as usual. But now you are told---in advance---that in both cities, the first thing that those handling the reconstitution boxes will do is to give you a cup of tea. The question is: "what is the probability, for the guy still in Helsinki, just before the experience, that he will live the experience of drinking a cup of tea?". Assuming comp and the usual default hypotheses, 'course.



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