On 8/09/2017 12:05 pm, Russell Standish wrote:
On Wed, Sep 06, 2017 at 05:39:07PM +1000, Bruce Kellett wrote:
On 6/09/2017 2:52 pm, Russell Standish wrote:
On Wed, Sep 06, 2017 at 11:44:12AM +1000, Bruce Kellett wrote:
I find the discussion in your book rather cursory, unless I have not
located the relevant passages -- numbers of pages or sections to
look at might help.
Time is discussed in S4.3,
That discussion is rather misleading. You introduce general
relativity to clarify the notion of coordinate time. But all you are
actually using is special relativistic Minkowski space -- in GR time
is extremely problematic since arbitrary coordinate transformations
can mix time and space in arbitrary ways. This is the problem of
time in GR, and there is no generally agreed solution.
My point about GR is the distinction it makes between coordinate time
and proper time. Proper time is the relevant concept for the TIME
postulate.
You really need only SR: proper time is the time kept by an inertial
clock. It gives only a local time ordering of events, but that is
probably all you want. The real problem is that your have introduced a
time parameter from thin air, as it were. Your ontology is static
bitstrings. Unless you can find a way for a useful time parameter to
emerge from that, your theory fails.
As you know, GR permits closed spacetime loops in some rather
exotic situations in such a case a given spacetime coordinate (event)
can be visited multiple times with different proper times. How to
interpret what that all means is, of course, an open question.
GR gives closed time loops only in very exotic cosmologies -- nothing
that need really concern us. My point about time in GR is that there is,
in general, no unique foliation of space time by spacelike hypersurfaces
that could give a natural temporal order -- the problem of 'many
fingered' time.
Julian
Barbour's work is a response to this general problem -- that is
really at the base of what I have proposed later. But I think you
'Time Postulate' in S4.3 is seriously deficient because you
essentially propose a topologically simple time parameter, which
does not exist in general relativity, Your discussion is deficient
in that it does not go beyond special relativity.
Topology applies to coordinate time. Not to proper time, which even in GR
is still a simple 1D real parameter.
In S4.3 you quote
Wheeler: "Time is what prevents everything happening at once." But
in a timeless block Minkowski universe, everything does, indeed,
happen at once: the observer moment corresponding to you as a baby
co-exists with your present observer moment. There is a temporal
relation between these two events, but that is intrinsic to the
events, not a separate ordering. No general foliation of space-time
into a sequence of spacelike hypersurfaces is possible in GR.
Which I've never implied.
The importance of Wheeler's quote is that events need to be separated
in time to allow an observer to measure a difference (that makes a
difference). One wonders if spatial separation should be enough, but
it appears that observers are not actually spatially extended things -
I forget now all the details, but this seems to be the conclusion of a
number of people in this area: Daniel Dennett and Michael Lockwood to
name two.
If the ontology, including observers, is timeless, then an apparent
temporal ordering must emerge from the structure of that static plenum.
You simply cannot brush away the problem by imposing a time parameter
from outside by fiat.
the projection postulate is described as
really anthropic selection, a concept discussed in S5.3. Lewontin's
principles are described in S6.1. S6.4 is an argument that we must
live in an evolutionary universe. Putting it all together for deriving
QM is discussed in S7.1.
Reliance on an evolutionary argument like this requires a
distinction between the observer and data, and I am doubting the
viability of that distinction.
I think there must always be a self-other distinction, a distinction
between observer and er environment. Consequently, there will be a
distinction between observer and observed (data). Brent Meeker has
also been banging on a bit about this over the years, particularly in
relation to the MGA.
I think Brent's point, with which I agree BTW, is that an observer can
only be defined in relation to an external world -- consciousness
requires a world to be conscious of! This does not necessitate a hard
distinction between the observer and the data. The observer might be the
way the data knows itself. In other words, the observer is also the data.
But there does seem to be a divide between the starting point of all
possible bitstrings and the operational idea of an observer
interpreting these strings. It seems to me that since the observer
must be part of these bitstrings, you have to make that central. So
an observer moment is the set of all bit sequences that correspond
to that moment -- there being nothing else that relates these
strings to each other. A different OM will be a different set of bit
sequences that pass through a separate moment. I presume you then
call on observer self-selection to join these separate sets into a
connected conscious experience.
Presumably, although I don't address this in the book, largely because
there is no concensus as to how to go about doing this.
I do not know how this might be, but
that seems to be what is required, if I have understood the set-up
correctly.
You haven't convinced me that it is required (yet).
Well, something has to connect up OMs. That function is performed by
Barbour's time capsules, but these are something that you have not
considered. I do not like the notion that development is simply a
process of accreting bits to the observer string.
I haven't considered it explicitly because it is something people are
in general very confused about.
But that does not justify one in simply ignoring the problem and
imposing an external time parameter by fiat.
Yes, Barbour's time capsules is one
approach, but it doesn't deal with memory erasure particularly well as
one of its problems.
I haven't heard of that as being a problem for the time capsule idea.
Time capsules are complete in themselves, and the past is only present
in so far as it leaves traces in the present. If something has been
forgotten, there is no trace of it in the present time capsule. Where is
the problem?
None of this requires that some set of bitstrings 'read'
or 'interpret' some other set that comprises the data -- the data
present in the observational moment is part of the OM itself.
I agree that the anthropic principle prohibits some (or indeed most)
strings from being observed by a given observer, but nevertheless, an
OM is a set of strings, so different strings can be read and
interpreted by an observer.
But you have not said how one string can read another. Or even what
that might mean.
I haven't said how a string can be conscious either. Of course not - that
would be providing a solution to Chalmers' hard problem. But if a
string can be conscious, then it is capable of reading and
interpreting any string you provide it.
Not if consciousness does not exist independently of the data ((external
world). Consciousness does not have to read anything -- nothing is
'presented to it'. It is complete with its environment and that
environment forms an essential part of the consciousness (conscious
experience). You are using essentially temporal concepts when you speak
of presenting a string to a consciousness, which then interprets it.
When an observer gains some new data, that is a new observer moment
to be built up in the same way. The set of bitstrings that go into
this new moment might well be completely disjoint from the previous
set,
Why would you propose this? It seems counter-intuitive. Intuitively,
one would expect a successor OM to build on its predecessor.
Not necessarily. That requires your time postulate as a minimum, and
general relativity effective rules that out.
I don't see this. See above comments on proper time.
OK, proper time is taken from SR and applied only locally, so the
concept is not ruled out by GR. The problem is still that you have
simply introduced a time parameter out of thin air. If you are to have
time in the picture, it must emerge from the timeless bitstrings, and
you have given no account of how this might happen.
Bruce
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