BIG successes of Lisp (was ...)

[Stephen Horne]

We observe electrons and make up mathematical theories etc etc, but in
reality little demons are driving them around.

Your assertion that there is an objective reality requires proof as
well. Probably it cannot be proved, but must be made an axiom. The
scientific method requires falsifiability.

I can't proove it exactly, but I think I can show the alternative to
be logically inconsistent quite simply.

If you assert that there is no objective reality - only perception -
then I have as much right to claim assert my perceptions as anyone
else. And I percieve that there is an objective reality.

The fact is we cannot perceive well enough to determine reality. The
physicists say that observation alters the result so if Heisenberg is
right there is no absolute reality. Perhaps by wishing hard I can get my
batteries to last longer 1 time in 10^67.

If that were true, why should it only work 1 time in 10^67?

As I said before, the limit of the accuracy of our perceptions is
basically the limit of information processing. *Not* information
theory - we need machinery to do the processing. That machinery has
limits, cannot be perfect, and thus is pretty well optimised to
achieve a purpose as well as possible without the need to be perfect.
The reason it can't percieve quantum effects is because we have no
evolutionary need to percieve things at that level, and thus have no
senses etc etc to deal with them.

Quantum effects are actually a good example, so lets take a look...

Yes, a particle may have two or more states at the same time. But once
*any* observer observes that particle, it resolves to the same state
for *all* observers. Individual observers cannot choose for themselves
what to perceive.

Still, it is worth asking what is so special about this observer. What
makes a particular arrangement of matter special, so that it can
'observe' while other arrangements cannot. Is it some mystic
metaphysical conscience, as many have asserted, or is it perhaps
nothing magical at all, and nothing to do with mind?

I tend to go with Penrose on this. That is, a superposition of states
has strict limits with respect to gravity. Whenever particles are in a
superposition, space-time must also be in a superposition. Particles
therefore have different levels of gravitational energy in each
superposition. This creates an uncertainty in the system. And as
Heisenberg states, a large uncertainty can only exist for a short
time.

Thus the reason why Schrodingers cat cannot be alive and dead at the
same time (at least for more than a tiny fraction of a second) is
because, as with any 'observer', it has a significant mass and
therefore the alive and dead superpositions create too much
uncertainty in spacetime.

Observers are nothing more than large masses that don't stay in
superposition states for significant times, and thus once the observer
(or cat, or for that matter vial of poison) is superposed the whole
system must rapidly resolve to one state or another because of the
scale of uncertainty involved in spacetime.

But it is easier to handle Schrodingers cat that that. According to
the thought experiment, any observation - no matter how indirect -
resolves the state of the system. But at the microscopic scale, that
is simply not the case - superposed particles interact with each other
in ways that allow the superposition of states to be detected, or else
the there could be no experimental proof of superpositions. There is
no such experimental proof at macroscopic scales, thus the same kind
of superposition simply cannot be happening (at perceptible
timescales) at the macroscopic scale.

Just as with relativity, the observer is certainly important but not
defining except in an extremely restricted way. There is a reality
which the observer is observing, and which the observer cannot define
arbitrarily.

Consciousness is not magic. Brains, like the rest of the body, are
just another arrangement of matter - certainly a complex and useful
arrangement, but it is still obeying (not defining) the rules layed
down by the universe we live in. There is nothing special about people
which lets them arbitrarily define the universe.

Awareness certainly mucks things up in socio-economic systems which are
also real in some sense. I hear people putting forward the view that
time is a construct of our minds; does time flow?

Take a look around and you will see that it does. Do you really
arbitrarily choose not to be able to observe next weeks lottery
numbers before you place your bet?

We know that the models provided by physics are imperfect. Maybe some
day someone will explain why time is different to space. Maybe not.
But what we are able to percieve does not define reality - it only
forms an imperfect model.

The fact that perception is not perfect does not mean there isn't a
defining reality to percieve. There must be something that ties all
our perceptions together, though, or else why are they sufficiently
compatible that we can interact at all.

This is a bit too meta-physical, but then much of modern physics is like
that. Since much of physics is done by counting events we are in the
position of the man who having jumped out of the top floor observes that
all's well after falling past the third floor as falling past floors
10,9,... etc didn't hurt. We cannot exclude exceptional events.

I'm not excluding the exceptional. I'm also not excluding what I can
see for myself just by opening my eyes.

 

[Stephen Horne]

Stephen Horne wrote:
...

You are so WONDERFULLY certain about such things -- including the
fact that "before" is crucial, i.e., the arrow of time has some
intrinsic meaning.

Take a look around. When you can walk back to last Wednesday, I'll
believe that time has no special meaning.

Just because physicists don't have a perfect model yet, it doesn't
change basic facts that anyone can observe by opening their eyes.

If you want to believe that time has no significance, proove it. When
you have successfully discounted all the clear and obvious artifacts
of times arrow, I will be happy to consider the possibility that times
arrow has no significance.

"observer-participancy" is a delightful way to say "perception", of
course

No. Perception does not require participation of any kind, except in
that sense (which does not imply control) in which any observation
involves an interaction and changes what it observes.

"deriving a working model of reality from sensory input" is what
perception is all about.

, but the most interesting part of this is that, to a theoretical-
enough physicist, the mere fact that something happens in the future is
obviously no bar to that something "building" something else in the past.

Yes, for the theoretician. It is a theoreticians job to test the
limits of the current models, and thus hopefully find better models.
But look around you. When was the last time you lived in a house that
was due to be built 50 years later?

The model is not reality, but only a working approximation of reality.
If the theoreticians could arbitrarily choose the results, why would
anyone bother with experiments?

Now, it IS quite possible, of course, that Wheeler's working hypothesis
that "the world is a self-synthesizing system of existences, built on
observer-participancy" will one day turn out to be unfounded -- once
somebody's gone to the trouble of developing it out completely in fully
predictive form, devise suitable experiments, and monitor results.

Or else someone could simply say "I do not require that hypothesis".

But to dismiss the hypothesis out of hand, "just because", does not
seem to me to be a productive stance. That the universe cannot have
built its own past through future acts of perception by existences
within the universe is "obvious"... but so, in the recent past, were
SO many other things, that just didn't turn out to hold....

Absolutely true. But take a close look at the pattern. The central
role of people in defining the universe is something that, step by
step, we are being forced to give up. We are not created in the image
of god, the Earth is not the center of the universe, and our minds are
no more special than any other arrangement of matter.

In quantum theory, the observer is nothing more than a sufficient mass
that a superposition must be resolved quickly. Not so long ago, people
were grasping to the idea that being an 'observer' in quantum physics
was a special function of human consciousness. I do not need that
hypothesis any more than I need the hypothesis of god, or the
hypothesis that we are living in the matrix acting as magical
batteries that somehow produce more energy than we consume.

Searle has written a book with a curiously similar title, "The
Construction of Social Reality", and takes hundreds of pages to defend
the view that there ARE "brute facts" independent of human actions
and perceptions -- but does NOT deny the existence of "social reality"
superimposed, so to speak, upon "brute reality".

Yes - but that "social reality" is nothing special either. There are
good practical reasons for it - reasons which can be derived fairly
simply from what we know of reality.

If you, like me, had Asperger syndrome you would understand the
practical consequences of not having full access to the definition of
"social reality".

As it happens, I have little patience for the constructionism vs.
deconstructionism thing. I have not chosen a side, and I do not see
deconstructionism as a single true faith. I do not believe all the
things that constructionists might say "then you must believe X" to.

To be honest, I don't see the point of basing opinions on what was
said by philosophers before the current level of knowledge about
physics and about the mind was achieved.

 

[Tayss]

Why?

Ok, here I need to make every line execute in order or it crashes.
The problem is that, like Lisp, Python wants to greedily execute any
function I give it. So if I try abstracting lines 1, 3 and 4 in a
function, like the following, it will execute line 2 first, crashing
the system:

def make_app(frame):
app = wxPySimpleApp() # 1
frame.Show(True) # 3
app.MainLoop() # 4

# oops, #2 is executed first. game over!
make_app( MainWindow(None, -1, "Sample editor") ) # 2


So I have to somehow wrap up line 2 in something so it won't greedily
execute. One way is to flash-freeze it in a function, say:
lambda: MainWindow(None, -1, "A window")

or freeze it in a list:
[MainWindow, None, -1, "A window"]

And these are possible solutions. But it's less readable and frankly
strange to anyone who has to read my code. It's a weird functional
trick to deal with side-effect ridden code. When I really just wanted
to make execution work in the right order. So I likely fail in making
it more readable and maintainable, which is the whole point in doing
this.

What's the problem in specifying the order of execution in functions?

Because in most languages (like Python and Lisp), functions don't give
the right amount of control over side-effects. They're great when
side-effects don't matter, but once they do, something like macros are
made for that situation.

Now, is this a big deal? Not really; it doesn't dominate the
advantages of using Python and wxPython. Just something I noticed.
But the tool is missing from the programmer's belt -- and whoever
defines a framework is already writing a new language that people must
deal with.

 

[John J. Lee]

What an outrageously off-topic thread, I can't resist it


What would it mean to 'prove that reality is not real', in fact??


It can vary in arbitrarily large ways. Our perception of the world is
based on our understanding of it (our models of it), including that
'understanding' embodied in our biology, put there by our evolutionary
past.


Absolutely! And there's no contradiction between that and the fact
that perception depends on both reality and our models of reality.

Actually it was not my intention to attempt any such proof, merely to
indicate that what we call real is at the mercy of perception.

The notion of reality is simply the working hypothesis that there's a
world out there to be understood, and that we have some hope of
understanding it, isn't it? Why give up on that until we get really
stuck? Science as a whole shows no sign of being stuck at present.

If I
choose to call a particular consensus version of reality the 'one true
reality' I'm almost certainly wrong.

What justification do you have for that statement?

As with most of current physics we
understand that 'reality' is a model.

Can you explain how that statement means anything at all?

An evolution based on low speed
physics hardly prepares us for quantum mechanics and spooky action at a
distance interactions. For that reality, which we cannot perceive, we
employ mathematicians as interpreters (priests?) to argue about the
number of hidden dimensions etc etc. Even causality is frowned upon in
some circles.

Well, they frown on it for no good reason. They're arbitrarily
setting aside a bunch of stuff and trying to legislate that
"everything works just *as if* it were real, except parts of it aren't
real". They can make that decision if they want to, but don't expect
others to likewise give up on science.

What we humans call 'reality' is completely determined by our senses and
the instruments we can build.

Well, your use of the word 'reality' is at odds with the way it's
usually understood (see above). You can use it in that way (where
most people would use the word 'model' in its place), but that only
serves to making communication more difficult.

How we interpret the data is powerfully
influenced by our social environment and history. As an example the

Oh, sure -- except that you're kind of implying that data even
*exists* in isolation from models of the world.

persistence of material objects is alleged by some to be true only for
small time scales <10^31 years; humans don't have long enough to learn
that.

It must be a mystery to you, then, how we know it. ;-)


John

 

[Tayss]

BTW, if in my other post you notice that in line 2
"A window"
morphs into
"Sample editor"

don't let it bother your subconscious. I was wrestling with google
groups to post (acting buggy recently, I wonder what's up..), and in
the process I cut 'n pasted the wrong stuff from my code. But it acts
the same, except for the window having a different title.

 

[John J. Lee]

We observe electrons and make up mathematical theories etc etc, but in
reality little demons are driving them around.

That's basically my model, too

Your assertion that there is an objective reality requires proof as
well.

It does not.

Probably it cannot be proved, but must be made an axiom. The
scientific method requires falsifiability.

It's the whole project of science to understand reality, so the
concept is outside of science. I guess the phrase 'existence of
reality' means pretty much the same as 'the degree of success of
science'.

The fact is we cannot perceive well enough to determine reality. The
physicists say that observation alters the result so if Heisenberg is

Those physicists are wrong, and Stephen is right. It's a bit of an
embarrassment to Physics that some physicists apparently still believe
in the Copenhagen interpretation.

right there is no absolute reality. Perhaps by wishing hard I can get my
batteries to last longer 1 time in 10^67.

No, but you can get them to last arbitrarily long by being *extremely*
lucky ;-)

Awareness certainly mucks things up in socio-economic systems which are
also real in some sense.

But there's no mystery or deep philosophical problem there.

I hear people putting forward the view that
time is a construct of our minds; does time flow?

No, 'the flow of time' doesn't really mean anything.

Any more deep mysteries you want me to clear up for you while I'm
about this? ;-)

This is a bit too meta-physical, but then much of modern physics is like
that. Since much of physics is done by counting events we are in the
position of the man who having jumped out of the top floor observes that
all's well after falling past the third floor as falling past floors
10,9,... etc didn't hurt. We cannot exclude exceptional events.

There's rather a big difference between the probabilities involved
there, Robin. We *could* be in a "Harry Potter Universe" of the sort
you hint at, but the word 'unlikely' hardly begins to describe the
magnitude of it!

I highly recommend David Deutsch's book "The Fabric of Reality", which
covers most of the stuff discussed in this thread.


John

 

[Rainer Deyke]

Your assertion that there is an objective reality requires proof as
well. Probably it cannot be proved, but must be made an axiom. The
scientific method requires falsifiability.

If the statement that there is an objective reality (or any other statement)
can be objectively proven either way, then objective truth (and hence
objective reality) exists. If it cannot, then the statement that there is
an objective reality is as true as any other statement, and requires no
proof.

 

[John J. Lee]

Stephen Horne wrote:
...

You are so WONDERFULLY certain about such things -- including the
fact that "before" is crucial, i.e., the arrow of time has some
intrinsic meaning.

Well, I agree that time-ordering is not important. I think the main
point is simply that reality is (defined as) independent of
perception, which he was illustrating with an example of a case where
perception was (or is, or will be, if you insist ;-) absent, but
reality was present. This is a somewhat metaphysical claim (though
perhaps the success of science in itself gives it scientific meaning).
It's the only sane metaphysical position to take, though, unless and
until science grinds to a halt. Anything else is either advocating
giving up on science, or merely playing around with language.

Physicist J. A. Wheeler (and his peer referees for the "IBM Journal
of Research and Development") didn't have your admirable certainty
that "reality is not about perception".

And it's Wheeler who's wrong, I suspect, not Stephen. And I mean
wrong in his epistemology, not merely wrong about some particular
theory.

[...]

course, but the most interesting part of this is that, to a theoretical-
enough physicist, the mere fact that something happens in the future is
obviously no bar to that something "building" something else in the past.

I don't have a problem with that a priori.

Now, it IS quite possible, of course, that Wheeler's working hypothesis
that "the world is a self-synthesizing system of existences, built on
observer-participancy" will one day turn out to be unfounded -- once
somebody's gone to the trouble of developing it out completely in fully
predictive form, devise suitable experiments, and monitor results.

[...]

Not having read the paper, I can't comment on that particular theory.
All I can say is that that there exist many 'zombie' theories in the
area of quantum mechanics and cosmology (and this thing of Wheeler's
has a suspiciously similar smell) which arbitrarily deny the existence
of some part of reality where some other extant theory does not. If
both theories are of equal explanatory and predictive power (as is the
case with the rival theories of quantum mechanics), the old one is no
longer rationally tenable. Now, OK, it's not *quite* as cut-and-dried
as that, because the ideas are hard and complicated, so I may simply
be mistaken about the particular theories we're discussing (I'd
certainly be a fool to say that John Wheeler hasn't thought deeply
about these things, or that my understanding of Physics approaches
his). But it's certainly true that some theories (the Copehagen
interpretation itself, for example, or the Inquisition's explanation
of the motions of the Solar System) that people continue to believe in
are indefensible because they arbitrarily reject the very existence of
some part of reality that another theory successfully explains. To
quote David Deutsch: "A prediction, or any assertion, that cannot be
defended might still be true, but an explanation that cannot be
defended is not an explanation".


Can't resist another quote from Deutsch ("The Fabric of Reality", in
the chapter "Criteria for Reality"):

There is a standard philosophical joke about a professor who gives a
lecture in defence of solipsism. So persuasive is the lecture that as
soon as it ends, several enthusiastic students hurry forward to shake
the professor's hand. "Wonderful. I agreed with every word," says
one student earnestly. "So did I," says another. "I am very
gratified to hear it," says the professor. "One so seldom has the
opportunity to meet fellow solipsists."


John

 

[John J. Lee]

If the statement that there is an objective reality (or any other statement)
can be objectively proven either way, then objective truth (and hence
objective reality) exists. If it cannot, then the statement that there is
an objective reality is as true as any other statement, and requires no
proof.

The justification of scientific knowledge doesn't require proof in the
usual sense of the word, so your statement seems ill-founded. My
guess is that the concept of reality is a metaphysical one, though
(inevitably quoting from Deutsch again):

"The reliability of scientific reasoning is ... a new fact about
physical reality itself..."


John

 

[John J. Lee]

[...this is Stephen again...]
Just because physicists don't have a perfect model yet, it doesn't
change basic facts that anyone can observe by opening their eyes.

'Basic facts that anyone can observe by opening their eyes' are
elusive things! The earth is not flat. All observations are made in
the context of a model of reality.

[...]

The central
role of people in defining the universe is something that, step by
step, we are being forced to give up. We are not created in the image
of god, the Earth is not the center of the universe,

Doubtful, but I can't be bothered to get into that.

and our minds are
no more special than any other arrangement of matter.

Unqualified, that's clearly nonsense.

In quantum theory, the observer is nothing more than a sufficient mass
that a superposition must be resolved quickly. Not so long ago, people
were grasping to the idea that being an 'observer' in quantum physics
was a special function of human consciousness. I do not need that
hypothesis any more than I need the hypothesis of god, or the
hypothesis that we are living in the matrix acting as magical
batteries that somehow produce more energy than we consume.

(I like your general thrust, but I think it's simpler than that -- the
many-worlds theory just says "let's forget about the collapse of the
wavefunction", and everything seems to work out fine.)

Yes - but that "social reality" is nothing special either. There are
good practical reasons for it - reasons which can be derived fairly
simply from what we know of reality.

Yes. We can explain the social aspects of reality even if not in
complete detail. It doesn't bring up any major philosophical
problems, French sociologists notwithstanding.

[...]

To be honest, I don't see the point of basing opinions on what was
said by philosophers before the current level of knowledge about
physics and about the mind was achieved.

Certainly some philosophers seem over-concerned with the history of
philosophy.


John

 

[John J. Lee]

Persistence of material objects will become obsolete much sooner. See:

http://crnano.org/systems.htm

This discusses three ethical systems and their usefulness for dealing
with the coming nanotechnology era.

But this is all quite irrelevant to the question of the validity of
realism. Robin and Anton both are merely making points about the
particular common-sense *models* of reality that we carry with us in
order to get through the dayy without spilling our coffee or trying to
walk through doors.

The articles conclusion has quite a Pythonic ring to it, I feel.
However just like Python, it will have to give up on backward
compatibility someday

Weak link, very weak, Anton. ;-) Still, at least you're trying, unlike
me...


John

 

[Stephen Horne]

[...this is Stephen again...]
Just because physicists don't have a perfect model yet, it doesn't
change basic facts that anyone can observe by opening their eyes.

'Basic facts that anyone can observe by opening their eyes' are
elusive things! The earth is not flat. All observations are made in
the context of a model of reality.

Well, I still think that the *local* 'flatness' of the Earths surface
is highly significant (at least the fact that the general
sphericalness has less significance at a local scale than the hills
and valleys and other lumps and bumps), even if only locally. Our
current models are much more general, of course, but showing that
something can be explained as local effects in a new and more general
model is not the same as proving that easily observable consistent
patterns are insignificant.

In the case of the Earths flatness, the historical model has not only
been superceded but now seems cringingly obsolete as our daily lives
have exceeded the limits of that model - not a day goes by without
some reminder of the non-flat nature of the Earth at non-local scales.

But are we likely to exceed the limits of perceptions where time is
significant any time soon? Ever? If so, how come no smug gits from the
future have come back to tell us how it is done?

If you say that our perception of time is not a universal absolute,
well some aspects of that are already proven fact and other aspects
are perfectly plausible. I have no problem with that. But to claim
that our local perception of time has no basis in our locally
perceptable 'region' of reality is, IMO, daft.

All the evidence shows that there is a consistent arrow of time that
we cannot opt out of - and 'local' in this case seems a lot bigger
than a few tens or hundreds of miles. Current evidence suggests that
works much the same in distant galaxies as it does in the next town
down the road, as long as we allow for relativity where relevant.

Unqualified, that's clearly nonsense.

It is qualified by the context of the discussion - the claims that
there is no reality separate from perception (and therefore that the
arrangement of matter called a brain has a special ability to write
the rules that all matter in the universe follows).

As I said in another post...

"""
Consciousness is not magic. Brains, like the rest of the body, are
just another arrangement of matter - certainly a complex and useful
arrangement, but it is still obeying (not defining) the rules layed
down by the universe we live in. There is nothing special about people
which lets them arbitrarily define the universe.
"""

Yes, the human brain is (currently, so far as we know) unique. It is
special. But it does not need magic powers in order to be special.

(I like your general thrust, but I think it's simpler than that -- the
many-worlds theory just says "let's forget about the collapse of the
wavefunction", and everything seems to work out fine.)

Yes, but why can we see the affects of superposition at the
microscopic scale but not at the macroscopic. That is what strikes me
as odd - if parallel universes work as an explanation, then why do
they work differently at the two scales. In particular, why can we not
see evidence of it at the scales we are good at percieving when we can
see the evidence so clearly at the scales we are not naturally
equipped to percieve at all.

Certainly some philosophers seem over-concerned with the history of
philosophy.

Looking at that again, I overstated it of course. Wisdom is not such a
cheap thing. But still, these philosophers simply did not have access
to much of the knowledge that, thanks to science, we now take
more-or-less for granted.


One last thought, at least for today...

If there is no reality separate from perception, and if 'reality' is
therefore just another perception, how come it is so bloody complex
and impossible for most of the organisms capable of perception to
understand?

When essentially everyone on Earth believed in a flat Earth, why was
there any perceptible evidence that the Earth was not flat - unless it
was because of an independent reality 'taking precedence' over
perceptions?

 

[Stephen Horne]

Weak link, very weak, Anton. ;-) Still, at least you're trying, unlike
me...

<desperate attempt to lighten the tone>

I'm *very* trying ;-)


OK, sorry for the bad joke.

 

[Robin Becker]

<desperate attempt to lighten the tone>

I'm *very* trying ;-)


OK, sorry for the bad joke.

Well here's even more fun the following quotes from this

http://www.scieng.flinders.edu.au/cpes/people/cahill_r/Semantic.html

seem to be in my corner, but as before I'm getting dizzy even reading
it.


'''
That process physics could be implemented by a model of Mind in the SNN
to reveal the fundamental semantic, temporal, experiential nature of
reality is deeply satisfying for a number of reasons: 1.) the essential
semantic nature of reality has been thrust upon us by the rigorously
proven limitations of self-referential syntactic systems, and so rests
upon the most secure imaginable and uncompromisingly honest intellectual
foundation; 2.) it is, of course, Mind in which semantic and the Meaning
to which it corresponds is ultimately registered[10]; 3.) Mind, as the
theoretical statistician turned economic theorist and pioneering
biophysical economist, Nicholas Georgescu-Roegen argues, appears to be
required for the experience of what Dr. Cahill calls the "present
moment" or the "now" required if we are to make meaningful observations
at all.
'''

'''
To elaborate upon this third point: Georgescu-Roegen tells us of an
illustration by Nobel Prize-winning physicist, Percy Bridgman, showing
that with the advent of relativity in physics, it is perfectly possible
for two separated observers travelling in different directions through
space to register a signal from a third position in space as two
different facts. One observer may, for instance, detect a " ‘a flash of
yellow light’ " while the second registers the same signal as " ‘a glow
of heat on his finger.’ " Bridgman’s point, according to Georgescu-
Roegen, is that for relativity to be able to assert that about the same
event implies that even relativity physics really presupposes
simultaneity in some absolute sense despite its attempt to show
simultaneity’s problematic nature with the registration of a single
event as two distinct facts. Furthermore, relativity physics does not
show how this absolute simultaneity could be established.
'''

 

[John J. Lee]

Well, I still think that the *local* 'flatness' of the Earths surface
is highly significant (at least the fact that the general

[...]

I think all this is irrelevant to the question at hand (realism).

It is qualified by the context of the discussion - the claims that
there is no reality separate from perception (and therefore that the
arrangement of matter called a brain has a special ability to write
the rules that all matter in the universe follows).

[...]

Oh, OK.

[...]

Yes, but why can we see the affects of superposition at the
microscopic scale but not at the macroscopic. That is what strikes me
as odd - if parallel universes work as an explanation, then why do
they work differently at the two scales. In particular, why can we not

They don't.

see evidence of it at the scales we are good at percieving when we can
see the evidence so clearly at the scales we are not naturally
equipped to percieve at all.

We see exactly the effects that the theory predicts. They're just
very small.


[...]

One last thought, at least for today...

If there is no reality separate from perception, and if 'reality' is
therefore just another perception, how come it is so bloody complex
and impossible for most of the organisms capable of perception to
understand?

[...]

Yeah -- hence the solipsism joke.


John

 

[Stephen Horne]

They don't.

Are you claiming that in schroedingers experiment that the dead and
live cats interact in some way that can be measured outside the box
without collapsing the waveform?

I was also under the impression that the largest 'particle' to be
successfully superposed in an experiment was a buckyball (or something
like that - at least a 'large' molecule of some kind or another) and
the timescale for that superposition was tiny.

Yet the whole point of the thought experiment is that according to the
theory, as conventionally described (I know next to nothing of the
detail), it should be possible for a cat to be superposed almost as
easily as it is possible for a subatomic particle - a simple
cause-and-effect chain is all that is needed. If that is the case,
superpositions of macroscopic objects should be happening all the
time.

Now either the superpositions are in parallel universes with each
state undetectable from an observer in another one of those universes,
or they are in the same universe and detectable in some way, or there
is a differentiation between the microscopic and macroscopic scales,
or - and this is very likely, I admit - I am seriously confused about
what the hell is going on (the natural state for a human confronted
with quantum theory).

We see exactly the effects that the theory predicts. They're just
very small.

OK - so why is it not possible to detect the superposition of that
cat? Why is the experiment still considered a thought experiment only?

I would have thought, with a huge number of particles affected by the
superposition of states, there would be a huge number of interactions
between the particles in those two superposed states.

Or am I just seeing the effects of superposition in the wrong way?

Yeah -- hence the solipsism joke.

Ah - sorry - I'm not actually familiar with that term.

 

[Thomas A. Russ]

Wrong. The computer can prove that I am done with the file the moment my
last reference to the file is gone. I demand nothing more (or less).

But in practice, the computer will only prove you are done with the file
the next time it decides to check. This is different from "the moment
my last reference...is gone" because for very good preformance reasons,
the computer doesn't check at each unbinding. (And no, reference counts
aren't a good idea either.)

Common Lisp as currently formulated does not have finalizers, although
there have been over the years proposals to add them. There are still
some unresolved issues regarding how to limit what such finalizers can
do. In any case, that will also not give immediate results.

 

[John J. Lee]

Are you claiming that in schroedingers experiment that the dead and
live cats interact in some way that can be measured outside the box
without collapsing the waveform?

Well, in the many-worlds interpretation (MWI) there *is* no
wavefunction collapse: everything just evolves deterministically
according to the Schrodinger equation. But of course, since cats are
big lumps of matter, one wouldn't expect to be able to measure
interference effects using cats.

I was also under the impression that the largest 'particle' to be
successfully superposed in an experiment was a buckyball (or something
like that - at least a 'large' molecule of some kind or another) and
the timescale for that superposition was tiny.

The largest *measured* superposition, yes. The Copenhagen
interpretation says that the world evolves according to the
Schrodinger equation until, um, it stops doing that, and collapses to
an eigenstate. When does the Copenhagen interpretation say the wfn
collapses? It doesn't! It denies any meaning to that question.
That's claiming that we just "shouldn't" ask about this part of
reality, and stop our enquiry there. Why should I follow that
instruction when the MWI explains exactly what happens? If a theory
explains more than its rival, one rejects the rival theory. And it
doesn't make any sense to say "there are many universes, except for
large objects, for which there is only one universe". This brings us
into epistemological issues which Deutsch deals with in his book much
better than I can.

Of course, there's more to this debate than Copenhagen vs. MWI, but
the other rival theories all (to my very limited knowledge) seem to be
either re-hashings of MWI in disguise, or complicated theories that
introduce ad-hoc irrelevancies without any compensating benefit. And,
to dispense with the absurd objection that MWI is 'expensive in
universes', since when has complexity of *entities* been a criterion
on which to judge a theory?? Complexity of *theories* of the world is
a problem, complexity of the world itself is not. Indeed, one thing
we know independent of any theory of quantum mechanics (QM) is that
the world is damned complicated!

Yet the whole point of the thought experiment is that according to the
theory, as conventionally described (I know next to nothing of the
detail), it should be possible for a cat to be superposed almost as
easily as it is possible for a subatomic particle - a simple
cause-and-effect chain is all that is needed. If that is the case,
superpositions of macroscopic objects should be happening all the
time.

They do, yes!

Now either the superpositions are in parallel universes with each
state undetectable from an observer in another one of those universes,

*The fact that those superpositions exist* is justified by the fact
that MWI is the best theory of QM that we have. The particular nature
of a particular large object's superposition is not measurable.
Contrary to popular belief, this raises no major epistemological
problems for MWI, and does not turn it into metaphysics.

or they are in the same universe and detectable in some way, or there
is a differentiation between the microscopic and macroscopic scales,
or - and this is very likely, I admit - I am seriously confused about
what the hell is going on (the natural state for a human confronted
with quantum theory).

Saying that superpositions are "in one universe" or another seems to
be playing mix-n-match with the various theories.

[...]

OK - so why is it not possible to detect the superposition of that
cat? Why is the experiment still considered a thought experiment only?

Simply because that's what QM predicts for large objects. The
'accident' of the size of Planck's constant means that interference
effects are small for large objects. The universes involved are none
the less real for that: denying that requires doublethink.
Interference effects aside, why *should* we experience anything
unusual when "we" (scare quotes because issues of personal identiy
come up here, of course) exist as a superposition, ie. when we exist
in multiple universes? There is a very close parallel here with
people's disbelief in the round-earth theory because they couldn't see
why they wouldn't fall off the earth if they moved too far from "the
top of the earth". Why don't we fall off the earth? Because the
(scientifically justified) theory says we won't. Why doesn't the me
in this universe experience multiple universes simultaneously?
Because the (scientifically justified) theory says I won't. Why
*should* we experience multiple universes? -- universes are entirely
independent of each other apart from interference effects that are
only large for very small objects, or slightly larger and very
carefully constructed ones.

But again, for those arguments in more detail you're vastly better
advised to go to David Deutsch's (extremely readable and enlightening)
book than to me

[...]

Ah - sorry - I'm not actually familiar with that term.

Well, explaining a joke always spoils it, but: a solipsist is a person
who believes that he is the only real thing in existence. The rest of
the universe, to a solipsist (to *the* solipsist, in fact ;-) is
simply the result of his own imaginings. Deutsch very clearly
presents an argument that this position is indefensible and
meaningless, starting from that joke I quoted.


John

 

[Richard Wesley]

Well, in the many-worlds interpretation (MWI) there *is* no
wavefunction collapse: everything just evolves deterministically
according to the Schrodinger equation. But of course, since cats are
big lumps of matter, one wouldn't expect to be able to measure
interference effects using cats.

For an interesting discussion of the shortcomings of MWI (not to mention
CI) have a look at

You all might also be interested in Objective Reduction theories. Some
of them suggest that the brain itself is a fairly large object in
superposition. See <http://www.consciousness.arizona.edu/quantum/>

Enjoy.

 

[Stephen Horne]

Well, in the many-worlds interpretation (MWI) there *is* no
wavefunction collapse: everything just evolves deterministically
according to the Schrodinger equation. But of course, since cats are
big lumps of matter, one wouldn't expect to be able to measure
interference effects using cats.

Ah - I think this is the key point. It has been some time since I
worried about *what* the detectable interactions actually are.

Of course, there's more to this debate than Copenhagen vs. MWI, but
the other rival theories all (to my very limited knowledge) seem to be
either re-hashings of MWI in disguise, or complicated theories that
introduce ad-hoc irrelevancies without any compensating benefit. And,
to dispense with the absurd objection that MWI is 'expensive in
universes', since when has complexity of *entities* been a criterion
on which to judge a theory?? Complexity of *theories* of the world is
a problem, complexity of the world itself is not. Indeed, one thing
we know independent of any theory of quantum mechanics (QM) is that
the world is damned complicated!

I still find Penfolds idea more intuitive than parallel universes, but
then intuitiveness is almost a sufficient counter in itself when
considering quantum theory!

In particular, I'd probably find the parallel universe theory more
intuitive if it were described in terms of a single universe with a
highly abstract set of rules. Different words can trigger different
perceptions while provinding an equivalent representation of the same
model, just as happens when you think in terms of the geometry of
spacetime rather than motion through space in time.



This thread has prompted me to revisit some of my books (on
consciousness, not quantum mechanics) and as a result I'm actually
reading Rita Carters 'consciousness' - I'd only dipped into a few bits
before, finding the chapter 'the hard problem' somewhat hard to
stomach.

It turns out that I am a materialist and a functionalist. Perhaps an
'emergenceist' too - function can be an emergent property as amply
demonstrated by evolution.

I just read a supposedly key counter to this viewpoint - a thought
experiment where a person has a 'backup brain', functionally identical
to his original brain but artificial and with the perceptions of red
and blue swapped so that red things would be percieved as blue (though
the behavioural consequences, e.g. the word used in speach, would be
unchanged due to the 'functionally identical' constraint).

The assertion is basically that, by switching between brains
(basically shuffling consciousness back and forth between the two
brains) the perception would constantly switch between 'red' and
'blue' yet there would be no reaction (because of the functional
equivalence requirement).

Yes, it's the old 'doesn't that seem daft' argument. But it's such an
easy argument to rip apart...

The concepts 'red' and 'blue' are abstractions - essentially
information. They need not be tied to particular neurons, just as a
variable in a program need not be tied to a particular physical memory
location (think virtual addressing, stack-relative addressing, virtual
memory, cache, CPU registers etc). Information exists, but has no
physical presence in itself.

Information can only exist in a practical sense, however, if there is
(at least) one representation of it in (at least) one medium. But that
representation does not need any independent labelling with meaning -
it can simply be an abstract symbol, whose meaning is entirely defined
by its functional consequences.

Of course there is likely to be some higher order representation in
reality, but if the person is aware of this change of perception (ie
is aware that the higher level representation keeps switching from
'red' to 'blue') then there will almost certainly be visible
functional consequences to that, just as there are functional
consequences to the very real phenomenon of synaesthesia.

Basically, I am asserting that a 'qualia' (basic unit of
consciousness) is simply an abstract concept much like (and consisting
of) information. Representations of that qualia may exist in many
parts of the brain simultaneously, and in different parts of the brain
from moment to moment - the qualia is not tied to particular neurons
in other words. And the meaning of those representations (and thus of
the qualia) can be entirely defined by the functional consequences of
the information processing in which those representations may
potentially participate. The qualia does not need to reside in a
particular piece of neural machinery, and it does not need any higher
order meaning associated with it beyond its functional consequences.

The person with the backup brain who alternately percieves red as red
and then as blue, but who cannot react to that change in perception,
simply cannot exist. Either there are functional consequences, or else
there is no difference in perception in the first place.

Moving on to the next thought experiment, to me the brain simply *is*
an example of Searles Chinese room. Its internal workings are as
invisible to us as that Chinese-room-operators use of English when he
refers back to his instruction manual. Higher level 'metaqualia' refer
to other qualia, not to particular symbolic representations. Self
awareness implies nothing I can see that cannot be explained by
sufficiently complex Chinese room rules. Which implies that any
Turing-complete machine can have consciousness.

OK, this takes some space to write in full, but despite that this all
really seems too obvious to me - odds are it took so long to write
purely because I'm too wordy and pedantic - I expect that someone has
written this more succinctly somewhere. The thing is that I find it
hard to see how these thought experiments can be stated as serious
things. When the abstract called information is so well understood,
how can the parallels with the abstract called consciousness be so
thoroughly ignored?

But then maybe I shouldn't ask that until I've finished the book.