On 10/7/2015 9:53 AM, smitra wrote:
On 07-10-2015 07:20, Brent Meeker wrote:
On 10/6/2015 8:11 PM, smitra wrote:
On 07-10-2015 02:04, Brent Meeker wrote:
On 10/6/2015 4:35 PM, smitra wrote:
On 07-10-2015 00:06, Bruce Kellett wrote:
On 7/10/2015 7:51 am, Brent Meeker wrote:
On 10/6/2015 1:18 PM, Stathis Papaioannou wrote:
I'm not sure I understand what you are getting at. I meant that
if the normal sequence of brain states is s1-s2-s3 with
corresponding mental states m1-m2-m3 and s2 is omitted, there
is nothing in m3 to give any indication of the discontinuity.
Of course, normally s2 is necessary in order to generate s1,
but that doesn't change the argument.
But I think that's wrong. Brains are not like ideal von Neumann
computers or Turing machines that have "brain states"
corresponding to "mental states". If you simulated a brain
using a computer you would find that an enormous number of
"brain states" were required to instantiate a single conscious
thought and furthermore the brains states necessary for one
thought overlapped with those necessary for the next thought.
So this overlap at the low level is part of the physical
continuity needed for consciousness. The fact that the physics
can be simulated by discrete computation doesn't imply that the
conscious states are discrete.
I think that is an important insight, Brent. One thing that it means
is that two brains can, by chance, be in the same physical state at
one instant, but those two brains might be supporting quite
different
thought processes. The consequence is that there is one person per
brain -- the same person can't be spread over several brains.
Bruce
That's impossible, two identical physical states within an
isolated system will yield the same (statistical) results when
measured. So, if one person would be experiencing something
different compared to the other person at that very instant then,
by definition, they were not in the same physical state at that
very moment, because that's how we define physical states to begin
with.
No, the contention is that a physical state, a state that obtains at a
single moment (Planck time?), does not instantiate a thought or an
experience. A thought or experience requires a sequence many physical
states and having two sequences share some subsequence of states is
not enough to make the two experiences the same. Consider an airport:
the fact that two runways cross doesn't make them the same runway.
Brent
Yes, this is the "observer moment problem" discussed a long time
ago in this list, but the requirement of needing a sequence of
states is also problematic, because at any given time I'm a
conscious being. This paradox is related to the well known paradox
where one argues that you can map the states of the brain of a
person as it evolves in time to that of a clock and then ask why the
clock isn't conscious.
Of course, the clock doesn't perform any computations,
Sure it does. It computes the time.
but to see this you have to consider the counterfactual inputs and
the corresponding counterfactual outputs.
Right. The problem is not that it doesn't compute anything, it's that
it doesn't interact with its environment so it has nothing to be
conscious of, except the time.
Then as I've argued here one or two years ago, a much better
solution is to invoke the MWI. Given your conscious experience, your
brain can still be in an astronomically large number of states. So,
instead of identifying yourself with the single branch, you should
consider the very large bundle branches that contain the same
macroscopic information.
The superposition of these states describes a person that is
entangled with the environment. This entanglement contains the
counterfactuals that you need to define what computation is
performed at any given moment.
I agree with that. But the hypothetical being argued was the inverse:
Suppose two persons/brains were is exactly same state.
But invoking the environment makes this a messy way out, a better
way i.m.o. is to include one computational step, you identify the
operator:
O = sum over inputs i of |output(i)><i|
as your observer moment . The summation is over states that fall
within your resolution,
But doesn't that just move the problem to determining which states
are "yours".
Well, the idea is that your observer moment at any time is an
algorithm in a well defined computational state, so to define it
requires specifying a list of inputs and their corresponding outputs,
which cannot be done in classical mechanics.
An interesting viewpoint. The "well defined computational state" is a
ray in a Hilbert space of a computer/brain?
In QM you can specify inputs and outputs, but you get different
probabilities for the outputs depending on the operator. Are you saying
that there is an observer moment operator and depending on the input it
may produce the output corresponding to Saibal's experience, but with a
different input it would produce Brent's experience? Or are you
supposing there must be different Saibal and Brent operators?
But in quantum mechanics, physical states are generically correlated
states and it's not a problem to specify a physical state representing
a well defined computation that nevertheless is defined at a specific
moment in time.
Yes I understand you can specify both initial and final state in QM.
But I'm not clear on how the state is equivalent to an algorithm. A
state usually refers to a specific time, while an algorithm refers to a
sequence of computational steps.
The classical picture leading to paradoxes is fundamentally flawed
precisely because you only get classical behavior due to entanglement
with the environment.
Right, that's part of my criticism of Bruno's idea. He depends on
deterministic computation, but that can only obtain in a wholistic model
that includes all the environment. Yet he tries to prove the reversal
of psychology and physics by considering very limited, isolated
computations modeled by movie frames.
Brent
Saibal
Brent
and this then partially defines a computation.
Saibal
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