Or one might argue that, for instance, you cannot have a well-defined concept of information without relating it to some form of consciousness (not necessarily human, in fact). — boundless
OK, my comment assumed it was an interpretation. But if the the different theory is experimentally differentiable from standard QM, then by all means let's devise the experiment.Obective collapse theories (such as GRW and Penrose's) are physically different theories to standard QM. I don't know what specific explanations they would give for this particular experiment. But they make predictions for Wigner's friend-style experiments that make them experimentally differentiable from standard QM. — Andrew M
My comment on that is about how Copenhagen deals with those implications, but since I understand that 'interpretation' to be an epistemological one, it doesn't really have implications for physical reality, only about what one observer might know vs another.As Brukner says in that link (my italics):
In my eyes, outcomes 1 and 2 would indicate fundamentally new physics. I will not consider these cases further and regard quantum theory to be a universal physical theory. This leaves us with situation 3 as the only possible outcome of Deutsch's thought experiment. The outcome is compatible with the Everett interpretation: each copy of the observer observes a definite but different outcome in different branches of the (multi)universe. The outcome is compatible with the Copenhagen interpretation too, but it is rarely discussed what the implications of this claim are for our understanding of physical reality within the interpretation. The rest of the current manuscript is devoted to this problem.
— On the quantum measurement problem - Caslav Brukner
From that exchange then:I'd be curious to know your thoughts about the RQM questions from my earlier exchange with boundless here.
They're almost the same thing, with different definitions of 'is real'. RQM says this world is real to me and a different world is real to anything else (the cat say), so they're both talking about different worlds. MWI says they're all equally real, and RQM says none are real, only that there are relations between worlds and observers. Neither requires an observer to by anything more sentient than a speck of dust, and I find any interpretation that requires otherwise to border on religion. Even Copenhagen, an epistemological interpretation, can be applied to the dust speck. It 'knows' about the wind because it reacts to it, and thus has a relationship with it. It is real in a way that something unmeasured isn't.Thanks boundless - they're excellent videos and well worth watching for anyone with an interest in the philosophical aspects of QM. Fun quote from Rovelli at 36 mins: "When I told Max (Tegmark) that he was a relationist, he told me that he is going to convince me that I'm, without knowing, a Many World believer." — Andrew M
I don't consider it a price to discard these things. Quite the opposite. All the threads on forums such as this one discussing some form of "why is there something, not nothing" take for a premise that there is something, and then run into all sorts of valid contradictions that follow from it. So it appears that the notion, however intuitive, of there being something is the thing with the price to pay. My answer to the above question is that perhaps there isn't anything, and thus there is no need to have to explain its being.Anyway, Rovelli has a slide at 40:15 that says:
The price to pay for RQM:
We need to get rid of the notion of:
- absolute (observer-independent) state of a system
- absolute (observer-independent) value of a physical quantity
- absolute (observer-independent) fact
Boundless echoes my mistrust of such intuitions. My username carries an implication of not taking any of them as a premise, at least not without explicitly calling them out. I'm always on the search for assumptions I don't even know I'm making and are thus unseen biases.But as I mentioned before I find (among other things) this 'oddness' as an indication that some kind of 'paradigm change' is required. Also, it seems that, in general, there is a trend to more and more 'counter-intuitiveness' in physics... — boundless
A lot of people had no trouble getting rid of absolute simultaneity when relativity came into acceptance a century ago. Some still cling to it religiously.The claim of RQM is that if you take this step, everything becomes simpler (cfr: special relativity, and the need of getting rid of absolute simultaneity.)
— RQM - Rovelli
Well it seems a real difference. There 'are' no branches at all in RQM, and they are 'are' in MWI. That's the huge difference such that I doubt an adherent to either interpretation can be convinced that they also hold to the other. Even the relations don't exist.My questions are:
1. Is this just a semantic difference with Many Worlds? (That is, there are nonetheless many physical branches, but there are only deemed to be facts relative to an observer's branch.)
2. If not, then what is the substantial physical difference and what explains physical interference effects? (Many Worlds would explain it as physical interference between branches.)
I can understand the unease with Bitbol's approach. But note that consciousness in his interpretation does not 'do' anything, in fact. It does not affect physical reality. It simply define the 'perspective' of the 'observer'. In a way analogous to Kant, Bitbol in fact IMO says that the 'quantum world' is indeterminate. But it is not a denial of it and neither he claims that it is 'modified' by consciousness. — boundless
All the threads on forums such as this one discussing some form of "why is there something, not nothing" take for a premise that there is something, and then run into all sorts of valid contradictions that follow from it. So it appears that the notion, however intuitive, of there being something is the thing with the price to pay. My answer to the above question is that perhaps there isn't anything, and thus there is no need to have to explain its being. — noAxioms
The price to pay for that is subjectivism/relativism/nihilism.
My view is that naturalism as a stance assumes the reality of the world (or rather, the sensory domain). There is nothing the matter with so doing, in fact, it's an essential methodological step. The problems start when the fact that it's a methodological step is forgotten, and it is mistaken for a metaphysical principle, or a statement about the real nature of things. In other words, methodological naturalism is interpreted as a metaphysical principle, which it is not. That is the whole issue, in a nutshell. (One way to avoid that is positivism, which says that only statements made on the basis of methodological naturalism are meaningful - but as has become evident, this too results in self-contradiction.) But the net result is, that the primacy of metaphysics has once again asserted itself through these conundrums posed by physics. — Wayfarer
With this I agree. I often characterize it the way Bohr did: as a description of what can be known, and not at all a description of what is. It is rather a jumping board by which a description of what is might be bounded. Others take their interpretation of what is and label it Copenhagen because it fits within these bounds.In CI, measurements are explained via the 'collapse' of the wave-function. The problem is, however, that CI is simply ambiguous on it. In fact, I would say that there is no 'Copenaghen Interpretation' at all. It is rather a 'class' of very different views that are, so to speak, 'grouped' together. — boundless
I thought the difference between the various interpretations often focuses on the treatment of the Heisenburg Cut. The Wigner's friend scenario basically puts one observer on either side of that cut, and drives out many of the differences between the interpretations.But where is the ambiguity? The problem is that the formalism of the theory alone does not identify what is the 'observer'. Yet, in order to explain the wave-function collapse you need to posit an 'observer'. If not, we cannot explain why our 'everyday world' looks classical, so to speak.
Isn't there a problem with this view in that without earlier collapse, none of these registered devices could possibly exist in the first place? If understanding of a measurement is what causes the collapse, how could the thing doing the understanding come about to do it? A chicken/egg problem.Anyway, let's see the proposed solutions to this intrinsic ambiguity of CI.
Firstly, one might try to say that, indeed, there are physical objects that count as 'observers'. For instance, objects that are able to store and process 'information', like e.g. computers, registering devices, brains etc. If I am not mistaken this is the view of Wheeler. The 'universe' is 'participatory' in this view because each of these 'observers' can 'modify' reality by 'collapsing' the wave-function.
That definition of 'measurement' is hardly confined in RQM. With the exception of anthropocentric Wigner interpretation, I think all the interpretations assume something along these lines, and even Wigner backed down from his own interpretation due to it reducing to solipsism.Secondly, another possible way to deal with this is to go with RQM (Relational Quantum Mechanics) as Rovelli et al do. Here, all physical systems can be 'observers' and the 'measurement' is simply a physical interaction.
OK, that is a point about CI. To know something about system X, I must exist, and I am classical, thus something needs to exist in a classic sense. MWI falls under CI then?This is because, according to Rovelli, there is nothing special about computers, etc:
"By using the word “observer” I do not make any reference to conscious, animate, or computing, or in any other manner special, system. I use the word “observer” in the sense in which it is con- ventionally used in Galilean relativity when we say that an object has a velocity “with respect to a certain ob- server”.
...
We do not need a human being, a cat, or a computer, to make use of this notion of information."
But Rovelli's RQM is, in fact, not classified as 'CI'. Why? Rovelli claims that QM is complete, whereas for CI you still need to consider something as classical.
The Wigner interpretation I referenced.Or one might argue that, for instance, you cannot have a well-defined concept of information without relating it to some form of consciousness (not necessarily human, in fact). And you end up with the 'Consciousness causes collapse' interpretation
How does this interpretation get around the chicken/egg problem if an observer is necessary for an observer to collapse out of a system? I presume Bitbol does not consider a dust mote to be an observer?Or a Kantian-like interpretation like the one proposed by Bitbol and others (and possibly of Bohr at least for some parts of his life, if Bitbol is right...) if you do not like the idea that consciousness really 'modifies' reality (but it is nevertheless necessary to have an 'observer').
Existential nihilism perhaps. Life still has meaning, even if that meaning isn't objective. Even a typical theist doesn't really consider say morality to be objective. Don't kill because God says it's wrong. 'Don't do it because I said so' is relative to the thing saying so, not objective.The price to pay for that is subjectivism/relativism/nihilism. — Wayfarer
My post above sort of indicates that while I don't mean to be nihilistic, I'm not sure the view doesn't lead necessarily to that camp.Anyway, I am not noAxioms, but I believe that his point was not 'nihilistic'. — boundless
if two people shine the sun light into each others eyes with a mirror at 25 feet apart , both will be in conflict with each other objective reality .You can use a garden hose and spray each other too . same difference — TRUE
It is meaningful to say that there are individual systems like S? That sounds an awful lot like counterfactual definiteness. A system with states still in complete superposition is still an existing system. There was no description of S existing in relation to R. Just 'there is a system S', which sounds more like MWI and not RQM.Basically, according to RQM you can only define a state of a system S in relation to something else. In other words, when you speak of the state of S you always need to specify the 'perspective' according to which you are making such a description. You can't avoid that.
So, RQM seems to imply that while there are 'individual' systems like S, their states are meaningfully defined only in relation to something else. — boundless
S does have intrinsic properties. I'm just balking at the suggestion that there is S, unqualified.But if S does not have any intrinsic properties, what does S, S?
? I would say we can only speak of objects. There is no 'no thing' view. That would be the objective view, things that exist without the relation, or with only an objective relation.I do not believe that RQM per se goes as far as denying that we can speak of individual objects, i.e. a 'no-thing' view, so to speak.
With this I agree. I often characterize it the way Bohr did: as a description of what can be known, and not at all a description of what is. It is rather a jumping board by which a description of what is might be bounded. Others take their interpretation of what is and label it Copenhagen because it fits within these bounds. — noAxioms
But where is the ambiguity? The problem is that the formalism of the theory alone does not identify what is the 'observer'. Yet, in order to explain the wave-function collapse you need to posit an 'observer'. If not, we cannot explain why our 'everyday world' looks classical, so to speak. — boundless
I thought the difference between the various interpretations often focuses on the treatment of the Heisenburg Cut. The Wigner's friend scenario basically puts one observer on either side of that cut, and drives out many of the differences between the interpretations. — noAxioms
Firstly, one might try to say that, indeed, there are physical objects that count as 'observers'. For instance, objects that are able to store and process 'information', like e.g. computers, registering devices, brains etc. If I am not mistaken this is the view of Wheeler. The 'universe' is 'participatory' in this view because each of these 'observers' can 'modify' reality by 'collapsing' the wave-function. — boundless
Isn't there a problem with this view in that without earlier collapse, none of these registered devices could possibly exist in the first place? If understanding of a measurement is what causes the collapse, how could the thing doing the understanding come about to do it? A chicken/egg problem. — noAxioms
Secondly, another possible way to deal with this is to go with RQM (Relational Quantum Mechanics) as Rovelli et al do. Here, all physical systems can be 'observers' and the 'measurement' is simply a physical interaction. — boundless
That definition of 'measurement' is hardly confined in RQM. — noAxioms
OK, that is a point about CI. To know something about system X, I must exist, and I am classical, thus something needs to exist in a classic sense. MWI falls under CI then? — noAxioms
Or one might argue that, for instance, you cannot have a well-defined concept of information without relating it to some form of consciousness (not necessarily human, in fact). And you end up with the 'Consciousness causes collapse' interpretation — boundless
The Wigner interpretation I referenced. — noAxioms
Or a Kantian-like interpretation like the one proposed by Bitbol and others (and possibly of Bohr at least for some parts of his life, if Bitbol is right...) if you do not like the idea that consciousness really 'modifies' reality (but it is nevertheless necessary to have an 'observer'). — boundless
How does this interpretation get around the chicken/egg problem if an observer is necessary for an observer to collapse out of a system? I presume Bitbol does not consider a dust mote to be an observer? — noAxioms
Anyway, I am not noAxioms, but I believe that his point was not 'nihilistic'. — boundless
My post above sort of indicates that while I don't mean to be nihilistic, I'm not sure the view doesn't lead necessarily to that camp. — noAxioms
It is meaningful to say that there are individual systems like S? That sounds an awful lot like counterfactual definiteness. A system with states still in complete superposition is still an existing system. There was no description of S existing in relation to R. Just 'there is a system S', which sounds more like MWI and not RQM. — noAxioms
S does have intrinsic properties. I'm just balking at the suggestion that there is S, unqualified. — noAxioms
? I would say we can only speak of objects. There is no 'no thing' view. That would be the objective view, things that exist without the relation, or with only an objective relation. — noAxioms
Basically, according to RQM you can only define a state of a system S in relation to something else. In other words, when you speak of the state of S you always need to specify the 'perspective' according to which you are making such a description. You can't avoid that. — boundless
If a view you find distasteful is more sound than one you'd like to be the case, does comfort trump logic?
Surely you have a spin on the whole 'why is there something' debate, else you'd have to face the subjectivism yourself.
Is time a property of the universe or does the universe, like any other object, exist in time? Only with the latter does it make sense for it to have come into being, in which case one has to posit a way that came about. Is there a first cause? RQM doesn't posit this 'being', so it doesn't have to answer to the conundrum. — noAxioms
Don't think there is such a cut with Wigner's interpretation. Consciousness causes collapse, period. If the cat is conscious, then it can't be in superposition of dead/alive. If not, then it can. There is no way to disprove this since there is no way to isolate a human in Schrodinger's box except by distance. I cannot take a human Alice and measure superposition on her. In principle I can, but there is just no practical way to prevent decoherence of a human. Alice is just not going to interfere with herself, even though I thought of a way for her to do it.I thought the difference between the various interpretations often focuses on the treatment of the Heisenburg Cut. The Wigner's friend scenario basically puts one observer on either side of that cut, and drives out many of the differences between the interpretations.
— noAxioms
I agree with this. Maybe Wigner himself however thought that all conscious observers are 'classical', i.e. according to him in the thought experiment Wigner's friend causes the collapse also with the respect to Wigner. — boundless
Does CI explicitly define measurement far enough to classify it in general as a 'registered device'? I thought it left measurement fairly undefined, allowing all sorts of interpretations on the spectrum from interaction through information processing and full on has-a-soul.Bingo! That's IMO the billion dollar question for all versions of CI. Classicality is both the result of collapse and the necessary condition of it.
Yes, that's the full-on definition. It is outside methodological naturalism, but not outside science. Wigner concluded that the interpretation led to solipsism partly because other consciousnesses will collapse waves functions differently, and that puts each of these consciousnesses in different physical worlds. If that's not the view, then you don't exist until I collapse you, and that again makes for solipsism.Note, though, that if you accept the versions of CI where consciousness has a special role and you do not have a physicalist theory of consciousness the argument you are making does not really apply. Why? Because, consciousness is not a result of a physical process. That's the point that, for instance, Bitbol makes (also Wayfarer makes this point in my understanding).
Not really. I don't formally know what Wheeler means by 'registration'. I tried to look it up but found the term only fairly well buried in papers beyond my ability to absorb. I used the word above, but only to echo the notion of a system that meets some unstated qualification of processing the information of measurement.That definition of 'measurement' is hardly confined in RQM.
— noAxioms
I am not completely sure. Take Wheeler's view for instance. While not giving a special role to consciousness, he nevertheless gives a special role to the act of registration. So, it seems that in CI 'measurement' is at least given by both the interaction and the act of registration. Does this make sense to you?
What I like has little to do with it. I'm interested in what works: is self consistent.Or a Kantian-like interpretation like the one proposed by Bitbol and others (and possibly of Bohr at least for some parts of his life, if Bitbol is right...) if you do not like the idea that consciousness really 'modifies' reality (but it is nevertheless necessary to have an 'observer').
Well it works I suppose. If consciousness is not a classical physical thing, then there's no chicken/egg problem. Still, how does it manage to collapse a state of total superposition into a state with matter present, let alone matter that can host consciousness? Collapse seems not to be in any way a function of will. I cannot will a measurement of vertical polarization, yet I would seem to need to do that to find my physical host.Yes, Bitbol does not consider a dust mote to be an observer. In my understanding, Bitbol thinks that only conscious beings can be observers.
Oh good, then you might take a stab at my questions, even though they're geared towards a Wigner sort of setup. Are you saying that consciousness is not physical?FWIW, I am not a 'physicalist' myself but I am not convinced that consciousness has a special role in QM.
If there's not another topic to discuss it, then why not here? I'm in no way against inter-subjective agreements. I just don't think that makes things objective. We both see the same moon, sort of, but the moon's existence is still relative. It totally doesn't exist to something that has taken no measurement of it, but it also doesn't stop existing to us if everybody looks away for a moment. It cannot be un-measured.Anyway, I am not noAxioms, but I believe that his point was not 'nihilistic'.
— boundless
My post above sort of indicates that while I don't mean to be nihilistic, I'm not sure the view doesn't lead necessarily to that camp.
— noAxioms
Oh, I see. I believe that it does not necessary lead to nihilism or relativism. After all, there is still the possibility of inter-subjective agreement on ethical matters (so in some sense we can still talk about 'objective ethics') in a similar way that there is inter-subjective agreement on scientific matters. [Maybe this is too off-topic, though]
S can define a perspective, yes. S is perhaps a collapsed state at some event say. Doesn't matter what the system is. The collapsed state here might be the two of us looking at a moon, and might be a moonless Earth without either of us, or it might be empty space between galaxies. In MWI speak, those are all existing worlds, and the we only exist in the first one, so the moon exists relative to that S and not to other potential states for the same collapsed S at that event.A system with states still in complete superposition is still an existing system. There was no description of S existing in relation to R. Just 'there is a system S', which sounds more like MWI and not RQM.
— noAxioms
So S defines a perspective and everything (i.e. all its properties) about it is defined in relation to other systems? Is there something about S that is not defined in relation to other systems?
Another question, maybe problematic: How is S in relation to itself?
You need to define S. This collection of atoms currently has an arbitrary box drawn around them and is designated as S or 'noAxioms' for the moment, even though many of those atoms come and go continuously. You may have a different idea if you have a different philosophy of mind and identity. For me, at best, my identity is the stuff in that abstract box drawn around a bunch of matter near a certain event, and the entire worldline that led to that event. That definition only works because I cannot subjectively split or merge. It wouldn't work for an amoeba, starfish, or a candle flame.S does have intrinsic properties. I'm just balking at the suggestion that there is S, unqualified.
— noAxioms
I'd agree with you if by 'intrinsic properties' you mean properties that distinguish S from other systems.
Maybe it isn't consistent. Hence the appreciated cage rattling.In this case, we would have that both S is associated with a perspective and everything about it is defined in relation to other objects. I am not sure if this position is fully consistent but it is very fascinating! :smile:
That sounds like a reference frame, which A) doesn't require an object stationary in that frame to define it, and B) has nothing to do with what causes a wave function to collapse. Rovelli says this in the context of equating that 'observer' to the mechanism that collapses/splits a wave function? I think not the latter. An observer is a point of view, but not necessarily something at that point observing, and not something that has an effect.. Just a point from which a description can be made. It does imply a partially collapsed state, so it isn't really defined without the table lamp, stationary or otherwise.Actually I read your [boundless's] account of Rovelli's 'observer' again, and there's something about it I can't buy. It says "I use the word “observer” in the sense in which it is conventionally used in Galilean relativity when we say that an object has a velocity “with respect to a certain observer”. The observer can be any physical object having a definite state of motion'. — Wayfarer
I kind of agree with this terminology being ambiguous, which is why I hesitate to use the word observation. Wave function collapse has presumably been going on long before any object has been capable of being this sort of 'observer'. So if I claim the table lamp takes a measurement of the air heating it, I'm not laying claim that it has subjective experience.I’ll spell out my bottom line - that all measurement or observation has a subjective aspect, i.e. it is undertaken by a subject, and the subject is (obviously) never disclosed in the act of observation, because observation is always of objects or at least of the objective domain.
Is that an answer? It is a of a different order or kind. OK, I can agree with that, but it isn't a specific answer. Indeed, I think it is a category error to treat the universe as an object, which, like all objects, doesn't exist, comes into being, and then exists (for a duration). 'Exists' means something different than how we use it for objects. But what does it mean actually? I find it to hold no distinction. An existing object is distinct from a non-existing one, but that is the object category. It seems not to apply to a universe category. That's just me and my relativist mindset. I'm sure you see a distinction, but you haven't really identified what 'order or kind' we're talking about here.Surely you have a spin on the whole 'why is there something' debate, else you'd have to face the subjectivism yourself.
— noAxioms
I think there's little understanding of the idea of 'first cause' nowadays. Because science has habituated us to thinking of causality in terms of material and efficient causation, then we can only conceive of 'first cause' as something at the temporal beginning of the sequence. But I think the original notion of the first cause is of a different order or kind to material and efficient causes.
Regarding Kaster's approach I am not sure to call it 'non-local'. — boundless
To be more complete, in fact I lean towards RQM and CI. The problem I have with RQM is that 'information' maybe is not something well-defined in relation to all physical systems. But as I said in my previous post, this is a quite controversial point. If 'information' is something that can be defined in relation to all physical system, then RQM is IMO the best choice.
If not, maybe something like Bitbol's interpretation (with maybe some elements of 'actuality/potentiality' dualism) would be best.
I am simply undecided. — boundless
They're almost the same thing, with different definitions of 'is real'. RQM says this world is real to me and a different world is real to anything else (the cat say), so they're both talking about different worlds. MWI says they're all equally real, and RQM says none are real, only that there are relations between worlds and observers.
...
Still, there are very 'real' differences between MWI and RQM, and I don't see how either Rovelli and Tegmark are going to convince the other that they hold the opposite view. — noAxioms
My answer to the above question is that perhaps there isn't anything, and thus there is no need to have to explain its being. — noAxioms
What is interference? It seems to be 'maybe' as an answer to a question not yet asked, a measurement not yet taken. So X = square root of 2 is 1.414 but also -1.414 and both those values can work through my equation until a choice must be make before the mathematics can continue. That's a measurement, and now there are two equations that proceed in different directions using a now real value for X instead of one in superposition. — noAxioms
An observer is one who takes notice of (and this means pays attention to) the thing which is observed. — Metaphysician Undercover
Right. And by my reckoning table lamps can’t do that. — Wayfarer
For instance, I say that my hand moves at a velocity v with respect to the lamp on my table. Velocity is a relational notion (in Galilean as well as in special relativistic physics), and thus it is always (explicitly or implicitly) referred to something; it is traditional to denote this something as the observer, but it is important in the following discussion to keep in mind that the observer can be a table lamp. — Carlos Rovelli
a pen on my table has information because it points in this or that direction. We do not need a human being, a cat, or a computer, to make use of this notion of information.
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