Re: Counterfactual Definiteness
Bruno et al: I think *"definiteness"* is always counterfactual since it *MUST* deny the potential influences from unknown factors (domains, a/effects, even some definitely counterfactual influences we do not recognize as such at all). It is a consequence of our agnostic view (as I recall: we agreed on such, at least to some degree) and our (accepted?) view on 'scientific' - as doubtful. I mean the 'counterfactual' mildly: it "counters" the factual *TOTAL* impact, not necessarily negating all the infuences. Our views are partial at best. I do not know much about rhe QM-related readings and am too old already to start learning. I accept my ignorance and try to live with it as long as I can. John Mikes On Sun, Apr 17, 2016 at 1:42 PM, Bruno Marchal <marc...@ulb.ac.be> wrote: > > On 16 Apr 2016, at 01:46, Bruce Kellett wrote: > > On 16/04/2016 12:20 am, Bruno Marchal wrote: > > On 14 Apr 2016, at 14:31, Bruce Kellett wrote: > > It is interesting that you have not answered my question about what > exactly you mean by 'counterfactual definiteness' so that we know what you > mean when you say that a theory is not counterfactually definite. > > > It is hard to define, especially if we avoid being technical. But we have > a good example: QM-with-collapse (or QM with a single universe). Like > Einstein already explain at the Solvay Meeting: if QM (with a single > universe) is correct, we can't ascribe an element of reality knowing a > result that we would obtain with certainty if we would make some > measurement, but will not do. Then Kochen and Specker proved that QM (+ a > single universe) is precisely like that. The proof does not apply to the > many-world, although it might apply to some too much naive rendering of the > many world (notably if we interpret wrongly the singlet state as I have > explained in previous post). > > > I do not understand what you are saying. Are you claiming that ordinary QM > with collapse is counterfactually definite because Einstein realism does > not apply? > > > > > > I say the contrary: t is NOT counterfactual making Einstein realism not > able to be applied. > > > > > > > > I.e., we cannot know with certainty what would have been the outcome of an > experiment that was not performed? (This is also the consequence of the > Kochen-Specker result that no set of hidden variables can predict the > results of all possible spin measurements on a spin 1/2 particle.) I would > have thought that this was one possible definition of counterfactual > *indefiniteness*. > > > I would be OK too. > > > > > What additional fact about MWI changes this conclusion? > > > None. Except that with a single physical reality that counterfactualness > entails non locality, but the same conunterfactualness with eother > computationalism and/or QM-without collapse does not entail physical nopn > locality, but only its statistical *appearances* in the memory of the > machine testing it. > > > > > Since in MWI all possible experiments are performed in some word or other, > I would have thought that experimental outcomes are available for all > possible experiments -- nothing is *actually* indefinite > > > It is relatively to you knowledge of a state. If you measure the position > very precisely, you "soul" is attached to an infinity of > "body/representation" with many definite, but different, momenta. > > If you measure something the result is definite only relatively to one > representation among many. If you look at the transfer of information in > the 3p picture of the entire quantum teleportation, you can see that the > information is spread locally at all times. It is even somehow made > explicit if you are using Bob Coecke's use category to describe such > quantum events. > > http://arxiv.org/abs/quant-ph/0402130 > http://arxiv.org/abs/quant-ph/0402014 > > -- even though not all outcomes occur in this one world that we happen to > inhabit at the moment. > > > There is no real sense to say that we inhabit a world. We are all the > times in an infinity of worlds/situation, which differentiate or not > relatively to what we interact with. > An electronic orbital is a sort of map of the set of all words we are > relatively to the possible energy of that "electron". > But by the linearity of the tensor product, we share the worlds only with > the person we interact with. > You might look at the Rubin's paper (provided by Scerir). Or Bob's Coocke. > > I will comment your other post with more detail perhaps later. But I do > not really grasp your > > << > A and B perform their measurements at spacelike separation, but each > chooses
Re: Counterfactual Definiteness
On 16 Apr 2016, at 01:46, Bruce Kellett wrote: On 16/04/2016 12:20 am, Bruno Marchal wrote: On 14 Apr 2016, at 14:31, Bruce Kellett wrote: It is interesting that you have not answered my question about what exactly you mean by 'counterfactual definiteness' so that we know what you mean when you say that a theory is not counterfactually definite. It is hard to define, especially if we avoid being technical. But we have a good example: QM-with-collapse (or QM with a single universe). Like Einstein already explain at the Solvay Meeting: if QM (with a single universe) is correct, we can't ascribe an element of reality knowing a result that we would obtain with certainty if we would make some measurement, but will not do. Then Kochen and Specker proved that QM (+ a single universe) is precisely like that. The proof does not apply to the many-world, although it might apply to some too much naive rendering of the many world (notably if we interpret wrongly the singlet state as I have explained in previous post). I do not understand what you are saying. Are you claiming that ordinary QM with collapse is counterfactually definite because Einstein realism does not apply? I say the contrary: t is NOT counterfactual making Einstein realism not able to be applied. I.e., we cannot know with certainty what would have been the outcome of an experiment that was not performed? (This is also the consequence of the Kochen-Specker result that no set of hidden variables can predict the results of all possible spin measurements on a spin 1/2 particle.) I would have thought that this was one possible definition of counterfactual indefiniteness. I would be OK too. What additional fact about MWI changes this conclusion? None. Except that with a single physical reality that counterfactualness entails non locality, but the same conunterfactualness with eother computationalism and/or QM-without collapse does not entail physical nopn locality, but only its statistical *appearances* in the memory of the machine testing it. Since in MWI all possible experiments are performed in some word or other, I would have thought that experimental outcomes are available for all possible experiments -- nothing is actually indefinite It is relatively to you knowledge of a state. If you measure the position very precisely, you "soul" is attached to an infinity of "body/representation" with many definite, but different, momenta. If you measure something the result is definite only relatively to one representation among many. If you look at the transfer of information in the 3p picture of the entire quantum teleportation, you can see that the information is spread locally at all times. It is even somehow made explicit if you are using Bob Coecke's use category to describe such quantum events. http://arxiv.org/abs/quant-ph/0402130 http://arxiv.org/abs/quant-ph/0402014 -- even though not all outcomes occur in this one world that we happen to inhabit at the moment. There is no real sense to say that we inhabit a world. We are all the times in an infinity of worlds/situation, which differentiate or not relatively to what we interact with. An electronic orbital is a sort of map of the set of all words we are relatively to the possible energy of that "electron". But by the linearity of the tensor product, we share the worlds only with the person we interact with. You might look at the Rubin's paper (provided by Scerir). Or Bob's Coocke. I will comment your other post with more detail perhaps later. But I do not really grasp your << A and B perform their measurements at spacelike separation, but each chooses the measurement orientation outside the light cone of the other. There are four possible combinations of results, corresponding to four worlds in the MWI: |+>|+'>, |+>|-'>, |->|+'>, and |->|-'>. Since each observer has a 50% chance of getting |+> and 50% of getting |->, and the two measurements are completely independent of each other, it would seem that each of these four worlds is equally likely. >> The expressions |+>|+'>, |+>|-'>, |->|+'>, and |->|-'> does not describe the superposition in which the observer will self-localize in: it is not the singlet state, which describe an infinity of worlds where all pair of particles of Bob and Alice are correlated. The whole point is that the result of the measurement does not describe the state we measure, but the partition of the sort of worlds to which we *relatively* belong. It is a bit long to verify by hand, but the linearity of tensor products and of the evolution makes the correlated state remaining correlated, and when one of them make a measurement, it just tell Bob in which partition of the multiverse he *and "his" Alice" belo
Counterfactual Definiteness
On 16/04/2016 12:20 am, Bruno Marchal wrote: On 14 Apr 2016, at 14:31, Bruce Kellett wrote: It is interesting that you have not answered my question about what exactly you mean by 'counterfactual definiteness' so that we know what you mean when you say that a theory is not counterfactually definite. It is hard to define, especially if we avoid being technical. But we have a good example: QM-with-collapse (or QM with a single universe). Like Einstein already explain at the Solvay Meeting: if QM (with a single universe) is correct, we can't ascribe an element of reality knowing a result that we would obtain with certainty if we would make some measurement, but will not do. Then Kochen and Specker proved that QM (+ a single universe) is precisely like that. The proof does not apply to the many-world, although it might apply to some too much naive rendering of the many world (notably if we interpret wrongly the singlet state as I have explained in previous post). I do not understand what you are saying. Are you claiming that ordinary QM with collapse is counterfactually definite because Einstein realism does not apply? I.e., we cannot know with certainty what would have been the outcome of an experiment that was not performed? (This is also the consequence of the Kochen-Specker result that no set of hidden variables can predict the results of all possible spin measurements on a spin 1/2 particle.) I would have thought that this was one possible definition of counterfactual /indefiniteness/. What additional fact about MWI changes this conclusion? Since in MWI all possible experiments are performed in some word or other, I would have thought that experimental outcomes are available for all possible experiments -- nothing is /actually/ indefinite -- even though not all outcomes occur in this one world that we happen to inhabit at the moment. Bruce -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
