Questions re Cramer's Transactional Interpretation?

[rkastner]

Yes, thanks, that's the paper I was thinking of. I agree that pure instrumentalist views are hard to rule out via the kind of proof presented by Pusey et al.

 

[rkastner]

Update: My book on the possibilist approach to TI and its relativistic extension is forthcoming this fall, http://www.cambridge.org/us/knowledge/isbn/item6860644/?site_locale=en_US

Also I uploaded the audio and ppt from my recent talk on how TI solves the measurement problem, here: http://transactionalinterpretation.org

 

[bohm2]

This is an interesting paper/EPR experiment that seems compatible with the Transactional Interpretation. Then again, I might be misunderstanding it?

The only reasonable resolution seems to be that of the Two-State-Vector Formalism, namely that the weak measurement's outcomes anticipate the experimenter’s future choice, even before the experimenter themselves knows what their choice is going to be. Causal loops are avoided by this anticipation remaining encrypted until the final outcomes enable to decipher it...Ergo, the weak measurements’ agreement with the strong measurements could have been obtained only by the former anticipating the spin orientation to be chosen for the latter. This result indicates the existence of a hidden variable of a very subtle type, namely the future state-vector...Therefore, when a weak measurement precedes a strong one, the only possible direction for the causal effect is from future to past.

The authors also suggest support for free will but I don't understand their argument:

Finally, this experiment sheds a new light on the age-old question of free will. Apparently, a measurement's anticipation of a human choice made much later renders the choice fully deterministic, bound by earlier causes. One profound result, however, shows that this is not the case. The choice anticipated by the weak outcomes can become known only after that choice is actually made. This inaccessibility, which prevents all causal paradoxes like “killing one's grandfather,” secures human choice full freedom from both past and future constraints.

Can a Future Choice Affect a Past Measurement's Outcome?
http://arxiv.org/ftp/arxiv/papers/1206/1206.6224.pdf

 

[audioloop]

I would classify the Copenhagen interpretation, as represented by Niels Bohr, under option 2 (e.g. Wavefunctions are epistemic, but there is no deeper underlying reality). One of his famous quotes is:
There is no quantum world. There is only an abstract physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature…[4]
and “what we can say” certainly seems to imply that we are talking about our knowledge of reality rather than reality itself. Various contemporary neo-Copenhagen approaches also fall under this option, e.g. the Quantum Bayesianism of Carlton Caves, Chris Fuchs and Ruediger Schack; Anton Zeilinger’s idea that quantum physics is only about information; and the view presently advocated by the philosopher Jeff Bub. These views are safe from refutation by the PBR theorem, although one may debate whether they are desirable on other grounds, e.g. the accusation of instrumentalism.

leifer say that, but...

Fuchs say

...The quantum system represents something real and independent of us; the quantum state represents a collection of subjective degrees of belief about something to do with that system (even if only in connection with our experimental kicks to it). The structure called quantum mechanics is about the interplay of these two things—the subjective and the objective.Chris Timpson

Realists about quantum mechanics may also want to be realists about the quantum state. But what does that mean? If one wants to think of the quantum state as representing a kind of thing, there is the question of what kind of thing that would be.----
...then, how many types of realism ?
quantum state realists, quantum system realists and quantum mechanics realists and various combinations between them...

 

[rkastner]

I provide an answer to the above question --

("...realists about the quantum state. But what does that mean? If one wants to think of the quantum state as representing a kind of thing, there is the question of what kind of thing that would be.")

-- in my new book, which you can get for a 20% discount here:

http://www.cambridge.org/us/knowledge/discountpromotion/?site_locale=en_US&code=L2TIQM

Also see my website, transactionalinterpretation.org, for introductory and preview material.