On 24/06/2017 11:20 am, Russell Standish wrote:
On Wed, Jun 21, 2017 at 04:21:09PM +1000, Bruce Kellett wrote:
On 21/06/2017 4:03 pm, Russell Standish wrote:
On Mon, Jun 19, 2017 at 12:15:31PM +1000, Bruce Kellett wrote:
On 19/06/2017 10:23 am, Russell Standish wrote:
I know Scott wouldn't go as far as me. For me, all such irreversible
processes are related to conscious entities in some way. Whilst
agreeing that Geiger counters are unlikely to be conscious, I would
say that the output of Geiger counter is not actually discrete until
observed by a conscious experimenter.
That sounds remarkably like the "many minds" interpretation of
quantum mechanics. This is disfavoured by most scientists because it
leaves the physics of the billions of years before the emergence of
the first "conscious" creature unresolved -- the first consciousness
would cause an almighty collapse on the many minds reading.
Each consciousness causes "an almighty collapse" in er own mind
independently of any other. It's a pure 1p phenomena.
It is actually a 3p phenomenon because there is inter-subjective
agreement about the fact that measurements give definite results.
There is no collapse at all at the 3p level, nor even decoherence as such.
Decoherence is a well-understood physical phenomenon that has been
widely observed. I do not know what you mean by saying "nor even
decoherence as such."
Thinking more on this, I think we may be arguing at cross purposes. In
the above, I was using decoherence to refer to idea of einselection in
a Multiverse, promoted by Zurek et al. In the multiverse, this
strictly speaking can't happen, because of unitarity. Einselection is
only a FAPP process, that ultimately manifests in the 1p of a
scientist.
It's dawned on me that when you refer to decoherence as a physical
phenomenon, you're really talking about this latter stuff, like how
difficult it is to maintain a coherent state in a quantum computer,
for instance.
Yes, in this instance I was referring just to the ubiquity of
environmental interactions, leading to the loss of coherence in quantum
states. The question of selecting a stable basis, or einselection in
Zurek's terminology, is clearly related to decoherence, though it does
take the idea a bit further. The physical problem that we face in
quantum mechanics is that we observe things in particular bases -- the
live/dead basis, not the (live+dead)/(liver-dead) basis, in the
Schrödinger cat thought experiment for example. The basis in which we
observe things is stable against further decoherence by environmental
interactions. It is argued (see Schlosshauer, for example) that the
stable einselected basis is the one in which the corresponding operators
commute with the interaction Hamiltonian. This is certainly a necessary
condition, but my feeling has been that this relationship is rather too
circular to really firmly ground the einselection argument.
You're not implying that you have physical evidence for
einselection in a multiverse (which is how I first read you, and if
true, deserving of a Nobel, I'd think). In any case, this latter stuff
is pure 1p. (1p plural, as Bruno Marchal might insist).
I think there is very good observational evidence for einselction -- the
basis in which we observe the world (or bases for different operators)
are very stable. It may, in the final analysis turn out to be FAPP, but
the fact that decoherence generally removes important coherence
information at the speed of light, the recombination time for natural
recovery of coherence tends to infinity in an expanding universe --
there is no Poincare recurrence time in de Sitter space! Such
considerations tend to suggest that decoherence is permanent feature of
the multiverse, not something that can ever be reversed. As I have said
elsewhere, unitarity is only a theoretical construct: a property of the
equations rather than a proven property of the universe.
Also, you seem to be confusing the
inter-subjective 3p view with Tegmark's bird view.
The 3p is what is left after removing all personal baggage of each 1p
view point. It is literally the view from nowhere (since location is
just such a baggage), and cannot be conscious in itself (for exactly
the reason you outline below)
It is this characterization of 3p that I find misleading. If all
personal baggage has been removed, how come you still talk as thought
this were a third person view? I think this terminology is an
unfortunate carry-over from the classical person-duplication thought
experiments. The bird view would more properly be called a 0p view,
since there are no 'persons' or 'person' who has this view.
Tegmark's "bird view" is somewhat poetic, but also ambiguous term,
in that it depends on what level of Multiverse you're talking about.
Sure, but we are talking about the level III quantum many worlds. I
don't know if one could give any meaning to a 'bird' view of Tegmark's
level IV multiverse. Because of the Hubble horizon, there can be no
actual person with the bird view of even the level I multiverse. So it
is all poetic, just as any outside view of the quantum many worlds from
which unitarity is evident.
If we propose the "antirealist" ontology, then all things must be
grounded in observerhood. I scare-quoted antirealist, because even
though we agreed on this definition in an ongoing conversation with a
colleague, it still causes confusion. But regardless of whether the
terminology is good, it is the idea that the 3p is the maximum
ontology, nothing else exists. In such a case, the 3p can be
identified with Tegmark's bird view.
It is still confusing to call this a 'third person' view.
There is still another datum. Because of the reasoning used in my
derivation of QM (appendix D of my book), I equate the 3p with the
quantum multiverse. Of course, my derivation may well be faulty - to
my knowledge, only a handful of people have dug into and critiqued
the argument in its 17 years of existence, without finding any fatal
flaw - however assuming its validity, then we can equate the 3p with
the bird view of Tegmark's level 3 multiverse.
I have not had the time or energy to delve deeply into your derivation.
My experience of other attempts to 'derive' quantum mechanics is that
basic quantum concepts are introduced by sleight-of-hand -- in other
words, they usually beg the question.
There is no
person, body, or consciousness that ever has the bird view -- the
bird is a purely formal construct and has nothing to do with mind or
consciousness. Even though everything might remain unitary at that
level, no one can ever experience the consequences of that unitary
evolution.
Yes, of course. And the same applies to the 3p.
Which is why it is a flawed terminology.
Bruce
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