On Mon, Dec 9, 2013 at 10:33 PM, meekerdb <meeke...@verizon.net> wrote:
On 12/9/2013 5:31 PM, Jason Resch wrote:
> On Mon, Dec 9, 2013 at 4:28 PM, meekerdb <meeke...@verizon.net> wrote:
>> On 12/9/2013 12:06 PM, Jason Resch wrote:
>> On Mon, Dec 9, 2013 at 12:57 PM, meekerdb <meeke...@verizon.net> wrote:
>>> On 12/9/2013 12:44 AM, LizR wrote:
>>> On 9 December 2013 20:56, meekerdb <meeke...@verizon.net> wrote:
>>>> On 12/8/2013 4:36 PM, LizR wrote:
>>>> On 9 December 2013 07:41, John Clark <johnkcl...@gmail.com> wrote:
>>>>> On Sun, Dec 8, 2013 at 11:48 AM, Jason Resch <jasonre...@gmail.com>wrote:
>>>>>> >> Determinism is far from "well established".
>>>>>> > It's a basic assumption in almost every scientific theory.
>>>>> In the most important theory in physics, Quantum Mechanics, no such
>>>>> assumption is made, and despite a century of trying no experiment has ever
>>>>> been performed that even hinted such a deterministic assumption should be
>>>>> added in.
>>>> I believe the two-slit experiment hints that QM is deterministic by
>>>> implying the existence of a multiverse.
>>>> Wasn't it you, Liz, that pointed out this was circular. Everett
>>>> assumes a multiverse in order to make QM determinsitic.
>>>> I did say something like that, didn't I? [insert embarrassed emoticon
>>> I think I was saying that it was too strong to say that QM "follows
>>> the principle of determinism" (or something like that) because it appears
>>> to be indeterminate and only becomes deterministic thanks to Everett.
>>> However, the two-slit experiment does *suggest* the multiverse as a
>>> valid explanation, in that any other explanation requires other principles
>>> to be violated (causality, locality...)
>>> I think I was attempting to position myself between John and Jason -
>>> to say that determinism is reasonably well established, but only as a
>>> result of a long and winding process of experiment, conjecture and so on.
>>> But it isn't. As Roland Omnes says, quantum mechanics is a
>>> probabilistic theory so it predicts probabilities - what did you expect?
>>> Among apostles of Everett there's a lot of trashing of Copenhagen. But
>>> Bohr's idea was that the classical world, where things happened and results
>>> were recorded, was *logically* prior to the quantum mechanics. QM was a
>>> way of making predictions about what could done and observed. Today what
>>> might be termed neo-Copenhagen is advocated by Chris Fuchs and maybe Scott
>>> Aronson. I highly recommend Scott's book "Quantum Computing Since
>>> Democritus". It's kind of heavy going in the middle, but if you're just
>>> interested in the philosophical implications you can skip to the last
>>> chapters. Violation of Bell's inequality can be used to guarantee the
>>> randomness of numbers, http://arxiv.org/pdf/0911.3427v3.pdf, assuming
>>> only locality.
>> Bell's theorm proves that local hidden variables are impossible which
>> leaves only two remaining explanations that explain the EPR paradox:
>> 1. Non-local, faster-than-light, relativity violating effects
>> That's non-local hidden variable - which is exactly what a parallel
>> universe is.
> There is nothing non-local about Everett's theory. You start with the
> electron and positron left over from the decay of a pi meson. They are each
> in a superposition of having a negative spin in the y axis and a positive
> spin on the y axis, but they are correlated in the following way:
> (e↑ × p↓) + (e↓ × p↑)
> Then one electron is sent to Earth and the other to the closest star,
> Proxima Centauri, where they are measured at about exact same time. After
> the scientists on Earth measure the electron, the state is as follows:
> (Earth↑ × e↑ × p↓) + (Earth↓ ×e↓ × p↑)
> Where Earth↑ represents earth scientists who measured the electron to
> have an up spin and Earth↓ represents earth scientists who measured the
> down spin for their electron. So far so good, nothing non-local has
> happened, only people on Earth are affected by the measurement of the
> electron (they have become part of the superposition). A fraction of a
> second later, the scientists at Proxima Centauri (4 light years away)
> measure their position, and the resulting superposition becomes:
> (Earth↑ × e↑ × p↓ × Proxima↓) + (Earth↓ ×e↓ × p↑ × Proxima↑)
> So now the scientists at Proxima Centauri have become part of the
> superposition, having measured both possible values. There is no need to
> enforce at speeds faster than light, any kind of agreement with the
> measurement by the remote groups of scientists, since both scientists
> measure both outcomes.
> Now when the scientists at Proxima Centauri measure their positron's
> spin, and send the result to Earth (to arrive 4 years later), the Earth
> scientists necessarily find that the radio signal indicates a result that
> corresponds to their own measurement. This is because the radio broadcast
> correlates with the measurement at Proxima Centauri, which is correlated
> with the positron, which is correlated with the electron, which is
> correlated with the measurement of the Earth scientists. Since they exist
> in distinct states of the superposition, it is impossible for the Earth↑
> scientists to hear from or otherwise interact with the Proxima↑ scientists,
> the Earth↑ scientists can only hear the radio broadcast that comes from the
> Proxima↓ scientists.
> Thus, the EPR paradox is solved without hidden variables (which were
> defined as extraneous properties not described by in quantum mechanical
> theory), and moreover, does so without violating special relativity. This
> solution comes directly from the literal reading of the Schrodinger
> equation. All the apparent paradoxes come from the assumption that collapse
> is fundamental.
> If you want collapse to be taken seriously, you must show evidence for
> it commensurate with the evidence that exists for other concepts in
> physics, because if the Copenhagen interpretation is true, then special
> relativity is false, locality is false, time-reversibility is false,
> determinism is false, causality is false, quantum computers are impossible,
> and observers are magical. This is a lot to give up for an interpretation
> that is not well-defined (how and when observation triggers collapse and
> even observation itself are not even defined), inconsistent in its
> treatment of multiple observers, and shown by Everett to be entirely
> redundant given the Schrodinger equation.
> Do you really think the Copenhagen interpretation is defensible given
> what we now know today?
> You keep assuming that every criticism of MWI is a defense of real
> collapse - it isn't. I think a proper reading of Copenhagen is epistemic
> collapse; in any case that seems to be the viable alternative.
So I have two questions for you:
1. Do you think "real collapse" theories are invalid or at least highly
unlikely to be true?
2. How is epistematic collapse different from Feynman telling his students
that collapse can only be modeled by the Schrodinger equation?
It seems to me that any theory in which collapse is not fundamental (and
normal quantum mechanical laws are obeyed) yields Everett's theory.
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 post to this group, send email to email@example.com.
Visit this group at http://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/groups/opt_out.