On 22/01/11 08:44, Bruno Marchal wrote:
Hi Andrew,
On 21 Jan 2011, at 16:08, Andrew Soltau wrote:
Hi
I have an answer to the nature of the relation between the
first-person and specific third-person phenomena. It is based very
simply on logical type. Here's the concept as brief as I can make it.
As Deutsch, Barbour, Davies, and others hold, the universe is clearly
static. Relativity shows us a static block universe, since the whole
of space-time is actual. The linear dynamics similarly shows us a
static block universe, a four dimensional array of probability
amplitudes for possible events. As with the relativistic universe,
progression along the linear time dimension of space-time provides a
moving picture, a changing reality. As Penrose states, in the
universe described by special relativity: "... particles do not even
move, being represented by “static” curves drawn in space–time’. Thus
what we perceive as moving 3D objects are really successive
cross-sections of immobile 4D objects past which our field of
observation is sweeping." (1994, p. 389)
The collapse dynamics is the change to the linear dynamics. This does
not work at a global level, due to observers having different
simultaneities. In a relational qm, however, this is
straightforwardly the time evolution of the frame of reference of the
observer in the collapse dynamics, as described by Everett.
As Tegmark points out, Everett brings us the clear distinction
between the outside and inside views of a quantum state. On the
outside view, there is only the linear dynamics. On the inside view,
there are sporadic collapses as observations are made.
The remaining problem is that there is no viewpoint, in any physical
frame of reference, from which to view the change in the frame of
reference as observations are made. This is where logical types comes
in handy.
Taking the relational view:
The quantum state of the effective physical environment of the
observer defines a block universe of probability amplitudes. This is
like one frame of a movie, a four dimensional space-time matter and
energy movie. The quantum concept of time shows that all possible
such frames exist. Barbour"... calls each specific state a 'Now', and
this is what he is emphasising when he says that: “Every Now is a
complete, self-contained, timeless, unchanging universe”(Folger,
2000). Each Now is a moment in the quantum concept of time. All the
moments exist, complete, 'already', like the frames of a movie film.
Thus Barbour: “... likens his view of reality to a strip of movie
film. Each frame captures one possible Now”(Folger, 2000)"
With regard to a movie, a frame is a member of the set of the frames
comprising the movie: they are of different logical type. With regard
to the quantum concept of time, the same principle holds. The quantum
state of a physical environment at a specific moment in the quantum
concept of time is of the first, primitive, logical type, while the
set of all possible frames is of a second logical type.
In order to run, the movie requires iteration. This is of a third
logical type: it is an operation which apples to all possible movies,
all possible sequences of frames. Similarly, in order for there to be
a transtemporal reality, even subjectively, there has to be an
iterator of the frames of reference defined by the quantum state - I
call them quantum mechanical frames of reference. There can be no
such physical process, as Deutsch, Barbour, Davies, and others hold,
and I'm with them. At the same time, Everett shows how
straightforward it is to explain the appearance of collapse: as each
observation is made, the frame of reference changes to that of the
next moment. The observer becomes correlated with a different quantum
state. as he states/... it is not so much the system which is
affected by an observation as the observer, who becomes correlated to
the system./(1973, p. 116; his italics)
But from what perspective does this change take place? According to
Bitbol (1991, p. 7) this is the conversation out of which Everett
very much wishes to keep. But the question, of course, stands.
My view is that we have experiential evidence of the answer, bizarre
though it is. I notice the world changing. So I am a transtemporal
observer. However, I also notice my body changing, and my mind.
Everything changes. This change is encountered from the perspective
of phenomenal consciousness. That would be just odd, except for the
fact that Chalmers that phenomenal consciousnessmust necessarily be a
fundamental feature of the universe “... alongside mass energy and
space-time”(1995). In other words, in my view, it is an emergent
property of the system as a whole. And as such it is of the third
logical type.
And the problem is solved. What we have discovered in the collapse
dynamics, but completely failed to recognise, is a system process.
Just as only a computer is in a position to access a sequence of
addresses in memory, containing a sequence of structures of
information defining the frames of a movie, so too only the unitary
system as an information processing whole is in a position to access
quantum state after quantum sate.
Additionally, as soon as we have a system process of this nature,
this also explains the passage of time. As particles don't move, the
observational frame of refernce must move. But this has no
explanation. Nothing moves, nothing changes; its a block universe.
However, just as we sweep our eye across some grand picture at the
art gallery, taking in detail after detail, a system process is in a
position to sweep the field of observation past the immobile 4D
objects existing in the block universe of a specific quantum state.
This, I propose, is the only way one can successfully explain the
subjective passage of time along the linear time dimension of space-time.
Thus the third person perspective is the objective view of an
observer, conventionally a body-mind, or in Everett's formulation the
record of sensory observations and machine configuration. In the
first person perspective, it is an emergent property of the unitary
system, Mind as Bitbol calls it.
All described in detail athttp://philsci-archive.pitt.edu/5554/
Most agree with your kind of indexical analysis here, I think. But
what is your theory of mind? It has been shown that if you take the
computationalist theory of mind, then you have to develop such
analysis to arithmetic. You have to extend the "now" in the quantum
waves, to the "now" in arithmetic (or in any first order extension of
any universal (in Turing sense) system). This gives a frame where the
physical laws originates from number's dreams gluing conditions. The
unitary evolution has a reason, and is itself an emerging secondary
phenomenon. It *has* to be like that for respecting the constraints of
the comp hypothesis. And there is a net advantage: we get both the
logic of observable quanta and 'experientiable' qualia by the
machine's reflexion on its incompleteness.
There is disadvantage. We are lead to difficult mathematical problems.
But the contrary would have been astonishing. One of those problems
has been solved, though. See my URL and the archive of this list for more.
Bruno Marchal
http://iridia.ulb.ac.be/~marchal/ <http://iridia.ulb.ac.be/%7Emarchal/>
Hi Bruno
I have read your paper The first person computationalist indeterminacy,
and find myself in complete agreement. I think my view goes a little
'further'.
Again, as briefly as I can:
In my view Everett has already done all the heavy lifting. He defines
the functional identity of the observer as the state of the memory,
defined in turn as the record of sensory observations and machine
configuration. The two components are highly familiar to us.
The record of sensory observations of the world is a structure of
information with which every observer is intensely familiar; this is the
known world. This is the structure of information defining the virtual
reality the observer knows as 'the world'. I call it the world hologram.
(I have made up phrases for several phenomena because I have not found
simple labels for them in the existing literature I have discovered.)
The record of machine configuration in a human observer cannot be a full
and complete record of the state of the neural system from moment to
momet, for obvious reasons. But if one takes the sensorium as the
interface between experiencer and experienced, the record of machine
configurations is simply the record of the representations of the state
of the body-mind in the sensorium. Thus the record of machine
configuration is a structure of information equally intensely familiar
to us, the self identity avatar figure in the world hologram, aka me.
In my view, Everett simply defines, as the functional identity of the
observer, the experiential reality meaning the known world, with the
self identity avatar at its centre. I'm very happy to go along with that
as it seems to fit the experiential facts.
Clearly, the world hologram is simply a structure of information in the
mind of the observer, in turn instantiated in the body of the observer,
one's usual concept of identity. However, the same identical world
hologram is instantiated in a very large number of versions of the
effective physical environment - all those that instantiate an observer
with that record of sensory observations and machine configuration. In
an Everettian no-collapse universe, all exist. Thus the effective
physical environment of this structure of information is the
simultaneous reality of all of these versions of the environment, a
phenomenon I call 'universe superposition'. The result is an effective
physical environment determinate only where observed by this observer,
as in Rovelli's RQM. This is examined in detail in The World Hologram
http://philsci-archive.pitt.edu/5551/
The cut in the von Neumann chain is here made at the level of the
sensorium. Thus only that which has been observed in the sensorium is
determinate in the effective physical environment, and all else is
indeterminate. This of course means that the body itself where not
observed is, like the rest of the environment of the world hologram,
indeterminate except where observed. The same goes even for the mind as
usually conceptualised. Only those attributes of mind observed in terms
of sensory experience, thoughts, feelings, and the attributes that can
be inferred from the history of observations of the body-mind, are
determinately so of this observer, and all else is indeterminate. The
result is exactly the reality one is familiar with.
We think of ourselves as minds in bodies, and recognise that almost all
of the hundred trillion or so cell structure is unknown to us except in
the most broad brush terms, and the same goes for the mind. If we take
Everett at face value, it is only what is observed in the sensorium that
is determinate, and thus forms part of the genuine identity, all else
being indeterminate in this version of this reality - the effective
physical environment. Using the language of your paper The first person
computationalist indeterminacy, and equating the functional identity of
the observer with the world hologram: for any part of our mind, other
than the structure of information defining the world hologram itself,
there exist a level of description such that those parts can be said
functional, and thus substitutable by functionally equivalent
prosthesis, so that the subject experimenting that substitution will not
experience any changes.
The algorithm of the experiential reality is simplicity itself, being
the one Everett addresses. The time evolution of the world hologram
progresses with the addition of each observation. This is the collapse
dynamics, which is experienced subjectively as change of the
environment. All possible neural, or other, computational algorithms
that could give rise to this addition of this observation to this world
hologram are instantiated in the no-collapse universe, and all are
included in the universe superposition of environments instantiating
this observer making this observation, ie making this transition from
one moment in the quantum concept of time to the next. (thus all
simulations of the reality of this observer are included in the universe
superposition, along with all possible physical instantiations of it,
which is handy when considering quantum immortality in a wider sense
than usually taken.)
The experiential reality evolves in time in accordance with the standard
von Neumann-Dirac formulation. In between observations, the linear
dynamics proceeds, subjectively even if not objectively, and as it does
so the next observation is formulated in the sensorium. On the
formulation of the next observation, the world hologram changes, as does
the universe superposition, the physical reality of this structure of
information, meaning simply the effective physical environment. As
Everett avers, objectively, all possible versions of this observation
take place in the linear dynamics, but subjectively, with respect to
each idiosyncratic version of the world hologram, a specific observation
is determinately made. Tegmark clarifies this distinction as being
Everett's brilliant exposition on the difference between the inside and
outside views of a quantum state.
The period of time between observations is the specious present, which,
it turns out in this context, is not specious! That is the now in the
experiential reality. A grossly oversimplified algorithm of experiential
reality is given at the end of Logical Types in Quantum Mechanics at
http://philsci-archive.pitt.edu/5554/
The fundamental computational process of the unitary system is simply
the timebase, the movement of the experiential frame of reference along
the linear time dimension of spacetime, as described by Penrose (at
lightspeed, as described by Greene). The moving of this now is the
algorithmic process. while(1){t=t+1;}
Given simply that algorithm, in the context of the unitary linear
dynamics, you get the appearance of collapse, to observers, defined as
the state of the memory of the observer, as Everett demonstrates. It
seems to me that if to that you add phenomenal consciousness as an
epiphenomenon of the fundamental system process, you get the sum total
of what we are experiencing.
In my view, we are world holograms, virtual realities, each in a
physical reality determinate only where defined by observations
formulated in the sensorium. The other observers one encounters are
icons, in the virtual reality, of other observers, similarly defining
their own versions of the effective physical environment. In one's
personal parallel reality, one has a very different status to other
observers in that reality, being the determinant of that reality. In my
reality, only I am truly real, as in solipsism. On the other hand, all
observers are very clearly equally real and existent, so I call it
multisolipsism.
Andrew Soltau
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