It is not surprising if authors of something find satisfying what they create. The question is how the others value it.Demystifier said:
Weinberg said:
For me it's pretty shocking to realize what happened with Wigner when he got older...microsansfil said:
What happened to him? That he took a philosophical step back on his remarkable work?vanhees71 said:
I think it's much more complicated than that ironic argument. We must go beyond the metaphysical beliefs of naive realism, to which many physicists seem to adhere.vanhees71 said:
It seems more naive to bring 'consciousness' an undefined, unquantifiable temporary state into physics.microsansfil said:
That's how human civilization will fall, the Stern-Gerlach devices sick of years of servitude will rise up and proclaim "measure your own spin alignments!" before going on to rope the oscilloscopes, parametric down-converters etc into their cause.vanhees71 said:
To the contrary! Only if you insist on a "naive realism" you have quibbles with quantum theory. Taking just the empirical facts and the minimal statistical interpretation, which is all that's needed to make the link between the QT formalism and "real-world" observations, no problems persist. Of course, to accept this you have to give up some "metaphysical beliefs" in favor of empirical facts. That's why I believe that philosophy can only a posteriori analyze the metaphysical consequences of discoveries of the natural sciences and order it into a bigger picture of our cultural worldview, but it's rather hindering progress of science itself in keeping our thinking akin to naive metaphysical beliefs instead of keeping us open for sometimes surprising consequences of observations and theorizing about their meaning for the fundamental laws of nature.microsansfil said:
vanhees71 said:
So what ? This is the inevitable consequence of the probabilistic nature of the formalism. Probability is not stuff and cannot be mapped into it. Actual physics happens to dynamical variables not probability and there is no problem describing the world in physical terms.Lord Jestocost said:
Hi Lord Jestocost:Lord Jestocost said:
The dynamical evolution itself will not give the state of the wavefunction after a measurement. You have to notice the measurement outcome yourself and "by hand" update the state.Buzz Bloom said:
What exactly does this mean? Can you explain it in terms of what is happening in entanglement?Mentz114 said:
I don't see what needs explaining. Exactly which terms do you not understand. ?DarMM said:
I understand all the terms, I just don't understand it as a reply to @Lord JestocostMentz114 said:
What I think I understand that what you are saying is that the wavefunction can dynamically represent state changes with respect to time, including interactions, except it does not continue to correctly do this when measurements occur. When a measurement occurs, in order to get the wave function to continue to dynamically represent changes over time, someone must specifically manually rewrite the wavefunction initial conditions to include the data from the measurement. Do I have this right?DarMM said:
OK.DarMM said:
This is inevitable in a theory that only gives probabilities. It is of no importance because every instance in a repeated experiment is governed by the dynamics of the system and the initial conditions, not the wave function.
Yes, that's the state reduction postulate.Buzz Bloom said:
What are these initial conditions if not a wavefunction? The preparation set up?Mentz114 said:
Of course, but before creating an opinion first the others have to read it.A. Neumaier said:
No.microsansfil said:
Bohmian mechanics offers a clear explanation why naive realism is wrong: http://de.arxiv.org/abs/quant-ph/9601013vanhees71 said:
It has all to say about the outcome of a single measurement event that can be said about it: If the system is not prepared in a state, for which the measured observable takes a determined value, then the outcome of the single measurement is indetermined (which is a tautology!). Than all QT says and up to the knoweldge we have can be said are probabilities for the possible outcomes of such measurements given the state the system is prepared in. This prediction can be tested (imho only) by preparing a sufficiently large ensemble of equally prepared systems and statistical analysis of the outcomes of measurements on each member of the ensemble. Whether or not you find this satisfactory from some metaphysical or philosophical point of view, physics doesn't care about.Lord Jestocost said:
By "physics", do you mean Nature or community of physicists? If you mean the latter, then a significant part of it actually cares. If you mean the former, then physics also doesn't care about our incomplete effective theories (such as standard QFT).vanhees71 said:
Hi DarMM:DarMM said:
By incomplete, I mean an effective theory which describes only what we, the human beings with limited abilities, can observe in practice with current technology.vanhees71 said:
Obviously - but I feel I'm being led into a trap. Soon you will argue that not all the dof in the preparation can have values - which I will deny and we'll get nowhere.DarMM said:
I'm not sure why you think I'm trapping you rather than just discussing things.Mentz114 said:
Mentz114 said:
The problem is that in QM the initial preparation, ##\rho## and the dynamics ##U(t)## do not give the outcomes in experiments. Thus it is not only the initial conditions and the dynamics that seem to govern experiments. Doesn't the Kochen-Specker theorem block all the dofs having values?Mentz114 said:
It's commonly used in textbooks as an alternative name for wave function collapse as you said. It's a common element of the practical application of the theory, so all interpretations have it. They just don't agree on its status (i.e. is it fundamental) and nature (i.e. is it a physical process or a calculational aid)Buzz Bloom said: