Thanks for this, Shan.

I’m worried you’re setting up a bit of a straw man version of psi-epistemic models (you call it the “realist psi-epistemic” view, an interesting choice of words). I’d be surprised if there were many (or any!) quantum foundations people who take such a view.

Specifically, you are ascribing the following logic to anyone…[Read more]

As Price & Wharton point out, once you consider QM to be giving 4D distributions in spacetime (Lagrangian schema), rather than time-evolved distributions in configuration space (Newtonian schema), mysteries like the MP are resolved trivially. This is a psi-epistemic view.

Hi Aurelien,

Nice post!

Regarding ontology of MWI, it appears that a preferred structure (partition into subsystems, including virtual subsystems) of the Universe is needed. Otherwise sufficiency of decoherence for defining “branches” and/or reality of “world branching” are at stake. More technically: there exist mutually irreducible,…[Read more]

This is an interesting solution. A version of it is discussed in section 4.4. of “Four Tails Problems for Dynamical Collapse Theories”. There it is discussed in the context of the matter-density interpretation of GRW (sometimes called “GRWm”). The “denser” brains are the ones with the experiences of measurement outcomes. Since high density is…[Read more]

Dear Shan dear all, I gave a kind of reply to Shan’s work concerning psycho physical parallelism in the topic ‘The End of the Many-Worlds? (or Could we save Everett’s interpretation)’

with best regards Aurélien

Dear Lev, don’t worry: my aim was only to recognize the influence that your view on MWI has on mine (your work on bohm with the ‘surrealistic’ bullet and the cat was very great as well). I will add a sentence that you dont share my view.
with best regards Aurélien

I thank Aurelien for citing my works, but his acknowledgement to me at the end of his paper is misleading. Although I tried to explain my views to him in a couple of e-mails, I failed. Reading his presentation of my views I could not recognize them at all. I disagree with everything I saw in Aurelien paper.
Lev Vaidman

OK, good. But I guess I’m inclined to stick to my guns here — the relative positions of the particles determine the measurement outcome. Suppose the first particle is the one whose spin is being measured, and the second particle marks the top of the detection screen. Then if the two particles end up close together, the incoming particle is…[Read more]

Thanks for the interesting post, Shan. Let me attempt to respond to your main argument. It is true that simply specifying the position of a Bohmian particle doesn’t pick out a measurement outcome. But neither does specifying the position of a classical particle. You need to specify the position of the particle relative to the apparatus — if it…[Read more]