On Mon, Dec 10, 2012 at 1:35 PM, meekerdb <meeke...@verizon.net> wrote:
> On 12/10/2012 10:16 AM, Jason Resch wrote: > > > > On Mon, Dec 10, 2012 at 10:30 AM, meekerdb <meeke...@verizon.net> wrote: > >> On 12/10/2012 2:56 AM, Bruno Marchal wrote: >> >> But why isn't "It's a probabilistic world and it obeys the Born rule." >> a good explanation. I'm all for finding a better explanation, i.e. a >> deterministic one. But simply postulating an ensemble of worlds to make >> the probabilities "deterministic" in arbitrary way doesn't strike me as any >> improvement. >> >> >> It is, as it explains interference, without adding something not well >> defined (apparatus, observer) not obeying QM (like with the collapse needed >> to get one physical reality). >> >> >> That sounds like prejudice against probabilistic theories. The >> interference is inherent in the complex Hilbert space states. The >> interference happens in one world. As Omnes says, you don't need >> 'collapse' you just need to accept that you have calculated probabilities. >> That's what probability means - some state is actualized and others aren't. >> >> > How does Omnes explain the EPR experiment without collapse? It seems > you need to give up not only determinism, but also locality. > > Also, what do you think Omnes would predict as the outcome for Deutsch's > proposed experiment: > > In Deutsch's thought experiment, an atom, which has a determinate spin > state in one axis, 'left' for example, is passed through a Stern-Gerlach > apparatus which has the possibility of measuring it in another axis, as > either spin 'up' or spin 'down' in this case. This means that the atom is > then in a superposition of 'up' and 'down' states from the perspective of > an observer who has not yet become entangled with it. This superposition > travels to the AI's artificial 'sense organ'. Here it is provided with two > options, it may be detected as either spin 'up' or spin 'down'. The AI's > conscious mind then records the result. The collapse approach predicts that > this will cause the atom to collapse into one determinate state, with > either a determinate 'up' or 'down' (but not 'left' or 'right') spin. The > Everett approach predicts that the mind will branch into two, one mind will > record up and one down (but neither will record 'left' or 'right'). > > The whole process is then reversed so that the atom emerges from the > entrance to the Stern-Gerlach apparatus and the mind forgets which result > it recorded. This process does not erase any of the AI's other memories > however, including the memory that they did record the atom to be in a > definite state. If a 'left-right' detector was placed at the entrance of > the Stern-Gerlach apparatus then the collapse approach predicts that it > will be detected as being in either a 'left' or 'right' state with equal > probability. > > > I think it is wrong in saying that the erasure of which-way information > (which I think is actually impossible for a consciousness, artificial or > otherwise) will leave the atom in an up/down state. > Isn't that exactly what the quantum erasure experiment shows? Why do you think it is impossible for a conscious process learn the result and then have that result erased as in the quantum eraser experiment? > You keep asking me about 'collapse', but Copenhagen's physical collapse is > not the same as Omnes epistemic collapse. > > I am sorry. I don't feel I have a good understanding of what the distinction is. Jason -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to email@example.com. To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.