On 8/2/2011 6:08 PM, meekerdb wrote:
On 8/2/2011 2:44 PM, Stephen P. King wrote:
On 8/2/2011 5:26 PM, meekerdb wrote:
On 8/2/2011 2:08 PM, Stephen P. King wrote:
On 8/2/2011 4:04 PM, meekerdb wrote:
On 8/2/2011 12:43 PM, Craig Weinberg wrote:
On Aug 2, 2:06 pm, "Stephen P. King"<[email protected]> wrote:
The point is that there is a point where the best possible
model or
computational simulation of a system is the system itself. The
fact that
it is impossible to create a model of a weather system that can
predict
*all* of its future behavior does not equal to a proof that one
cannot
create an approximately accurate model of a weather system. One
has to
trade off accuracy for feasibility.
I agree that's true, and by that definition, we can certainly make
cybernetic systems which can approximate the appearance of
consciousness in the eyes of most human clients of those systems for
the scope of their intended purpose. To get beyond that level of
accuracy, you may need to get down to the cellular, genetic, or
molecular level, in which case it's not really worth the trouble
of re-
inventing life just to get a friendlier sounding voicemail.
Craig
So now you agree that a simulation of a brain at the molecular
level would suffice to produce consciousness (although of course
it would be much more efficient to actually use molecules instead
of computationally simulating them). This would be a good reason
to say 'no' to the doctor, since even though you could simulate
the molecules and their interactions, quantum randomness would
prevent you from controlling their interactions with the molecules
in the rest of your brain. Bruno's argument would still go
through, but the 'doctor' might have to replace not only your
brain but a big chunk of the universe with which it interacts.
However, most people who have read Tegmark's paper understand that
the brain must be essentially classical as a computer and so a
simulation, even one of molecules, could be quasi-classical, i.e.
local.
Brent
Hi Brent,
I wonder if you would make a friendly wager with me about the
veracity of Tegmark's claims about the brain being "essentially
classical"? I bet $1 US (payable via Paypal) that he is dead wrong
*and* that the proof that the brain actively involves quantum
phenomena that are discounted by Tegmark will emerge within two
years. We already have evidence that the photosynthesis process in
plants involves quantum coherence, there is an experiment being
designed now to test the coherence in the retina of the human eye.
http://www.ghuth.com/2010/02/03/another-finding-of-quantum-coherence-in-a-photosynthetic-biological-system/
http://www.ghuth.com/2011/04/24/quantum-coherence-and-the-retina/
Those are not really to the point. Of course the brain involves
quantum processes and some of these involve coherence for short
times. But Tegmark argues that the times are too short to be
relevant to neural signaling and information processing. There's an
implicit assumption that neural activity is responsible for thought
- that the 'doctor' could substitute at the neuron level. I think
this is right and it is supported by evolutionary considerations.
We wouldn't want an intelligent Mars Rover to make decisions based
on quantum randomness except in rare circumstance (like Buridan's
ass) and it wouldn't be evolutionarily advantageous for an organism
on Earth. I'm glad to accept your bet; except that I'm not sure how
to resolve it. It don't think finding something like the energy
transfer involving coherence in photosynthesis or photon detection
is relevant.
No, my thought is that quantum coherence accounts for, among
other things, the way that sense data is continuously integrated into
a whole.
What integrated whole do you refer to? Our memory of a life? How
does it account for it?
This is not rocket surgery, come on! Think! Did you ever happen to
notice that, modulo variations in distance, the sounds you hear, the
things you see, feels, taste, etc. are all integrated together? How is
it that, modulo deya vu and similar synesthesias and dislexia, the brain
generates a vritual reality version of the world around you that is
amazingly free of latency? While there are visual effects that replicate
aliasing effects, such as when we see the spokes of a wheel turning
backwards, the ability of the brain to turn all those signals into a
single and integrated virtual world is amazing, but more amazing still
is the fact that there is something in the brain that acts like an
observer, something that lead many in the past to speculate about a
homunculus...
This leads to a situation that Daniel C. Dennett calls the "Cartesian
Theater". Dennett's proof that it cannot exist because it generates
infinite regress of homunculi inside humonculi is flawed because such
infinities can only occur if each of the humonculi has access to
sufficient computational resources to generate the rest of them. When
we understand that computations require the utilization of resources
and do not occur 'for free' we see that the entire case against
situations that imply the possibility of infinite regress fails.
I don't understand that. Are you agreeing with Dennett that an
infinite regress cannot occur or are you arguing that the need to pay
for resources makes them possible?
Dennet'ts argument in Consciousness Explained centers around
building up and then knocking down the "Cartesian Theater", based on the
supposed fact that it generates an infinite regress. My claim is that
his argument loses it motivation since the brain does not have the
computational resources to generate a regress of arbitrary depth. It
needs only to only generate a regress that is 3 or 4 levels deep. Marius
Buliga has an interesting blog post about some of Dennett's issues here:
http://chorasimilarity.wordpress.com/2011/06/06/the-cartesian-theater-philosophy-of-mind-versus-aerography/
The idea is that we can in fact have simulations withing
simulations within simulations without the problematic infinite regress.
A model of Self within a model of self + world is not a problem, pace
Dennett.
Quantum phenomena is NOT all about randomness. Frankly I would
really like to understand how that rubbish of an idea still is held
in seriously thinking people! There is not randomness in QM, there in
only the physical inability to predict exactly when some quantum
event will occur in advance. It is because QM system cannot be copied
that makes it impossible to predict their behavior in advance, not
because of some inherent randomness!
Sounds like a distinction without a difference. It's still a good
reason for evolution to favor a quasi-classical brain.
There are effects within QM that do not exist in the classical
regime, effects that can be used to do things that classical systems
cannot do. I am drawing from unpublished work by a friend of mine so I
cannot give more details on this unfortunately. :-(
Take the infamous radioactive atom in the Schrodinger Cat box. Is its
decay strictly a "random" phenomena? Not really! QM says not one word
about randomness,
See Born's projection postulate.
Note the word "postulate". The Born postulate is added to the QM
formalism as a means to explain probabilities. Its status is
controversial and not settled at all even today! How many texts books on
QM have you read? I recommend Bohm's.
it only allows us to calculate the half-life of said atom and that
calculation is as good as is possible given the fact that we cannot
generate a simulation of that atom and its environment and all of the
interactions thereof in a way that we can get predictions about its
behavior in advance.
As to your post here. Craig's point is that the simulated
brain, even if simulated down to the molecular level, will only be
a simulation and 'think simulate thoughts'. If said simulated brain
has a consiousness it will be its own, not that some other brain.
Craig's position seems to be more a blur than a point. He has said
that only biological neurons can instantiate consciousness and only
a conscious being can act like a conscious being. That would imply
that a being with an artificial, e.g. silicon chip based, brain
cannot act like a conscious being.
You care completely failing to understand that Craig is not stuck
in the box of canned answers to questions about the kinds of things
that we discuss in this List. While I will quibble with the claim
that "biological neurons can instantiate consciousness" as I believe
that consciousness is not just a 'phenomena of carbon based
chemistry', it is obvious that 'only a conscious being can act like a
conscious being", that follows from the basic principle of Identity.
A thing is itself and it behaves as itself would. A trivial fact but
one that gets ignored too often.
A consciousness can no more be copied than the state of a QM system.
That's the point in question. If Tegmark is right, it can.
Tegmark is wrong.
But you have not proposed any way to resolve the bet.
Pfft, whatever. Re-read what I wrote. Are you just trying to
demonstrate that you are the smartest guy in the room or are you
genuinely interested in figuring out how Everything works?
Onward!
Stephen
Brent
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