On Saturday, November 25, 2017 at 11:55:47 AM UTC-6, agrays...@gmail.com wrote: > > > > On Saturday, November 25, 2017 at 3:06:50 PM UTC, Lawrence Crowell wrote: >> >> On Thursday, November 23, 2017 at 9:21:14 PM UTC-6, agrays...@gmail.com >> wrote: >>> >>> >>> >>> On Thursday, November 23, 2017 at 11:15:40 PM UTC, Lawrence Crowell >>> wrote: >>>> >>>> >>>> >>>> I am new to this list and have not followed all the arguments here. In >>>> weighing in here I might be making an error of not addressing things >>>> properly. >>>> >>>> Consider quantum entanglements, say the entanglements of two spin 1/2 >>>> particles. In the singlet state |+>|-> + |->|+> we really do not have the >>>> two spin particles. The entanglement state is all that is identifiable. >>>> The >>>> degrees of freedom for the two spins are replaced with those of the >>>> entanglement state. It really makes no sense to talk about the individual >>>> spin particles existing. If the observer makes a measurement that results >>>> in a measurement the entanglement state is "violently" lost, the >>>> entanglement phase is transmitted to the needle states of the apparatus, >>>> and the individual spin degrees of freedom replace the entanglement. >>>> >>>> We have some trouble understanding this, for the decoherence of the >>>> entangled state occurs with that state as a "unit;" it is blind to any >>>> idea >>>> there is some "geography" associated with the individual spins. There in >>>> fact really is no such thing as the individual spins. The loss of the >>>> entangled state replaces that with the two spin states. Since there is no >>>> "metric" specifying where the spins are before the measurement there is no >>>> sense to ideas of any causal action that ties the two resulting spins. >>>> >>>> This chaffs our idea of physical causality, but this is because we are >>>> thinking in classical terms. There are two ways of thinking about our >>>> problem with understanding whether quantum mechanics is ontic or >>>> epistemic. >>>> >>> >>> The fact that probability waves evolve and interfere with each other, >>> and effect ensembles but not individual members, is inherently baffling. So >>> the wf can't be completely epistemic since it modifies physical reality. >>> That is, It must be ontic in some respect, but in ways that defy rational >>> analysis. AG >>> >> >> I think you are falling into a trap that David Hume warns against. >> Causality gives rise to correlation, but correlation is not necessarily the >> result of causality. There is no effect or some causal principle at work >> with either individual wave functions or wave functions in an ensemble of >> experiments. The ensemble of experiments, the classic case being the two >> slit experiment, is meant to deduces the wave nature of the quantum >> physics. It is not there to deduce some causal influence underlying quantum >> nonlocality. >> >> LC >> > > Applying deBroglie's formula, a change in p changes the wave length, and > thus the distribution on the screen. That is, the ensemble responds to > changes in the wave length due to interference. I therefore deduce that the > wave length has a physical effect on the ensemble, but not on individual > outcomes. AG >
You continue to make the error of thinking there must be some physical effect in a measurement. The outcomes will obey a statistical distribution that is reflected in an ensemble of experiments. The statistical distribution is predicted by the nature of the wave function prior to a measurement. The wave function can be interpreted in a ψ-epistemic sense (Copenhagen, Qubism etc) as only telling you what information can be accessed from the quantum system. In a ψ-ontic sense (MWI, Bohm etc) the wave function exists and evolves to define possible outcomes, but the observer is not able to access any predictive information as this necessitates some local hidden variable that does not exist. What outcome happens in any particular measurements is not predictable; there exists no causal principle which can tell you how a particular outcome obtains. The occurrence of a statistical distribution of outcomes from an ensemble of measurements does not mean there is some causal influence directing outcomes. This distribution only obtains as a consequence of what the wave function tells you (ψ-epistemology) about the system before measurement, or how the wave function evolves as a physical system (ψ-ontology) prior to measurement. It is my thinking that QM fails to completely live up to either of these. LC -- 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.
