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BIG successes of Lisp (was ...)

In the context of LATEX, some Pythonista asked what the big
successes of Lisp were. I think there were at least three *big*
successes.

a. orbitz.com web site uses Lisp for algorithms, etc.
b. Yahoo store was originally written in Lisp.
c. Emacs

The issues with these will probably come up, so I might as well
mention them myself (which will also make this a more balanced
post)

a. AFAIK Orbitz frequently has to be shut down for maintenance
(read "full garbage collection" - I'm just guessing: with
generational garbage collection, you still have to do full
garbage collection once in a while, and on a system like that
it can take a while)

b. AFAIK, Yahoo Store was eventually rewritten in a non-Lisp.
Why? I'd tell you, but then I'd have to kill you :)

c. Emacs has a reputation for being slow and bloated. But then
it's not written in Common Lisp.

Are ViaWeb and Orbitz bigger successes than LATEX? Do they
have more users? It depends. Does viewing a PDF file made
with LATEX make you a user of LATEX? Does visiting Yahoo
store make you a user of ViaWeb?

For the sake of being balanced: there were also some *big*
failures, such as Lisp Machines. They failed because
they could not compete with UNIX (SUN, SGI) in a time when
performance, multi-userism and uptime were of prime importance.
(Older LispM's just leaked memory until they were shut down,
newer versions overcame that problem but others remained)

Another big failure that is often _attributed_ to Lisp is AI,
of course. But I don't think one should blame a language
for AI not happening. Marvin Mins ky, for example,
blames Robotics and Neural Networks for that.
Jul 18 '05
303 15473
On 27 Oct 2003 20:57:02 +0000, jj*@pobox.com (John J. Lee) wrote:
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.
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #251
jj*@pobox.com (John J. Lee) wrote in message news:<87************@pobox.com>...
<snip obversations about MWI>


I cannot let pass this thread without some personal observation.

1. First of all, let me point out that I have a background in Theoretical Physics
and I have done research for the last ten years in the fields of supergravity,
quantum field theory, cosmology and other more exoteric subjects. So, I do
think I qualify as a "theoretical enough" physicists.

2. Second, I do think I have an idea about what are the fields of interests in
Physics nowadays; I also know for sure that the idea I had when I was an outsider
to Physics was completely wrong, so others may be in the same situation as I was.

3. Do you know how many research conferences are devolved to the
Multi-World Interpretation of quantum mechanics with respect to the number
of conferences in other fields such as QCD, or neutrino Physics, or even
magnetic materials?
The answer is very few. Actually, if you skip the conferences organized by
philosophers, the interdisciplinary conferences, the parallel sessions on
bigger workshops and you concentrate only on research conferences, the
answer will be *very very* few.

4. If I ask to virtually every theoretical physicist I know (and I know a
lot of physicists) about the MWI, they say "Come on, let's do real Physics".

5. I never had a course on MWI; no university I know about teach it to students.
Students are always (and often only) taught the standard interpretation; and
in any case nobody would ever think to teach it "instead of" the standard
interpretation. It could be taught as an alternative view, but in my
experience (most or all) universities skip it completely.

6. If you ask why <exaggeration mode> nobody except dean professors near
retirement </exaggeration mode> is interested in MWI you will likely get
the following answers:

1. it is an old business;
2. it is only an interpretation, gives no new predictions, so why bother?
3. cannot be generalized to relativity, so it is not relevant;
4. there are much more interesting things to study.

I admit that I am a bit exaggerating here, but let me do it. If there are
physicists doing MWI reading this, please, you are free to flame me ;)
Still all my experience in Physics tell me that MWI is dismissed by the
vast majority of Physicists, not on the basis of philosophical reasons,
but on the basis of pragmatical considerations such as "even if they are
right, I have something better to do".

7. The press has the ability of giving a completely false impressions about
what physicists are doing: you find lots of general public books about
MWI and philosophy of science, but very few about magnetic materials.
So, you have the impression that physicists prefer MWI over magnetic
materials, but actually the converse is much closer to the truth. Also,
I would bet that magnetic materials (which I do know a bit) are
mathematically much nicer than the MWI (which I don't really know, so
I may be wrong).

8. I do like philosophical questioning and I thing it is okay to ask
questions, but still people should be aware of the distinction
between speculations (something smart speculations, something
idiotic speculations) and scientifically relevant questions.
Now, smart speculations may turn out to become scientifically
relevant questions, but smart speculations are unfortunately so rare ...

A good rule of the thumb is "never believe anything you read and you don't
understand". Sometimes, you should not believe even what you think you
understand ...
Michele

P.S. I really liked the joke about solipsism ;)

P.P.S. I don't blindly believe the standard interpretation. I think
it is a "wart" of Physics which will hopefully pass. I look
with interest to the new ideas on decoherence, dunno if there
are general public books on it yet, but I would read one if
I find it ;)
Jul 18 '05 #252
mi**@pitt.edu (Michele Simionato) writes:
jj*@pobox.com (John J. Lee) wrote in message news:<87************@pobox.com>...
<snip obversations about MWI>
I cannot let pass this thread without some personal observation.

[...snip most of a huge list of arguments from authority...]
4. If I ask to virtually every theoretical physicist I know (and I know a
lot of physicists) about the MWI, they say "Come on, let's do real Physics".
Well, perhaps the sample consisting of "Physicists Michele Simionato
knows" has *some* merit <wink>, but the single serious survey of
"great and good" Physicists' opinions I have read about (sorry, can't
give reference... but I think it must have been either in one of those
flaky books by Frank Tipler, or in Deutsch's "The Fabric of Reality"
that I read about it) revealed that a large majority believed
(essentially -- obviously there are subtleties) in the MWI. Not sure
when that was carried out either, but it was back when Feynman was
still alive.

7. The press has the ability of giving a completely false impressions about
what physicists are doing: you find lots of general public books about [...]

Perhaps, but that has no relevance to the question of the reality of
multiple universes, of course.

8. I do like philosophical questioning and I thing it is okay to ask
questions, but still people should be aware of the distinction
between speculations (something smart speculations, something
idiotic speculations) and scientifically relevant questions. [...]

Precisely, and IMHO (as well as, if you want argument from authority,
rather cleverer folks, like Deutsch), it's *YOU* that's confused about
that distinction! This is a hugely important point, so I'm glad it's
that point that you picked out of the detail in this thread. Science
is about reality, not prediction, and the MWI is a theory, not an
interpretation.

Skipping back a bit:
4. there are much more interesting things to study.
Certainly people like Deutsch do get quite pissed off that they have
to spend time defending what should be a done deal by now, taking time
away from more productive and interesting Physics work. In fact, he
loudly complains about it in his book, and not just wrt MWI: the same
problem occurs in evolutionary theory, for example (and there is
actually an interesting connection between MWI and natural selection).

[...] P.S. I really liked the joke about solipsism ;)
But that was *your* joke, Michele! It's merely your *interpretation*
of the data that I really exist -- in *reality*, I'm just a figment of
your imagination <wink>.

(But I guess it's okay to laugh at your own jokes if you're the
solipsist :-)

P.P.S. I don't blindly believe the standard interpretation. I think
it is a "wart" of Physics which will hopefully pass. I look

[...]

Already has! :-)
John
Jul 18 '05 #253
an***@vredegoor.doge.nl (Anton Vredegoor) wrote in message news:<bn**********@news.hccnet.nl>...
There *is* no fixed past.


George Orwell's "1984" makes always a great reading.

Michele
Jul 18 '05 #254
Robin Becker <ro***@jessikat.fsnet.co.uk> wrote in message news:<t8**************@jessikat.fsnet.co.uk>...
Even causality is frowned upon in some circles.


Then avoid those circles. When somebody questions the causality
principle
I always point out the Summa Theologica, Part I, Question XXV, art. 4,
"Whether God can make the past not to have been?".

---

Objection 1: It seems that God can make the past not to have been.
For what is impossible in itself is much more impossible than that
which is only impossible accidentally. But God can do what is
impossible in itself, as to give sight to the blind, or to raise the
dead. Therefore, and much more can He do what is only impossible
accidentally. Now for the past not to have been is impossible
accidentally: thus for Socrates not to be running is accidentally
impossible, from the fact that his running is a thing of the past.
Therefore God can make the past not to have been.
Objection 2: Further, what God could do, He can do now, since His
power is not lessened. But God could have effected, before Socrates
ran, that he should not run. Therefore, when he has run, God could
effect that he did not run.
Objection 3: Further, charity is a more excellent virtue than
virginity. But God can supply charity that is lost; therefore also
lost virginity. Therefore He can so effect that what was corrupt
should not have been corrupt.
On the contrary, Jerome says (Ep. 22 ad Eustoch.): "Although God can
do all things, He cannot make a thing that is corrupt not to have been
corrupted." Therefore, for the same reason, He cannot effect that
anything else which is past should not have been.
I answer that, As was said above (Question [7], Article [2]), there
does not fall under the scope of God's omnipotence anything that
implies a contradiction. Now that the past should not have been
implies a contradiction. For as it implies a contradiction to say that
Socrates is sitting, and is not sitting, so does it to say that he
sat, and did not sit. But to say that he did sit is to say that it
happened in the past. To say that he did not sit, is to say that it
did not happen. Whence, that the past should not have been, does not
come under the scope of divine power. This is what Augustine means
when he says (Contra Faust. xxix, 5): "Whosoever says, If God is
almighty, let Him make what is done as if it were not done, does not
see that this is to say: If God is almighty let Him effect that what
is true, by the very fact that it is true, be false": and the
Philosopher says (Ethic. vi, 2): "Of this one thing alone is God
deprived---namely, to make undone the things that have been done."
Reply to Objection 1: Although it is impossible accidentally for the
past not to have been, if one considers the past thing itself, as, for
instance, the running of Socrates; nevertheless, if the past thing is
considered as past, that it should not have been is impossible, not
only in itself, but absolutely since it implies a contradiction. Thus,
it is more impossible than the raising of the dead; in which there is
nothing contradictory, because this is reckoned impossible in
reference to some power, that is to say, some natural power; for such
impossible things do come beneath the scope of divine power.
Reply to Objection 2: As God, in accordance with the perfection of
the divine power, can do all things, and yet some things are not
subject to His power, because they fall short of being possible; so,
also, if we regard the immutability of the divine power, whatever God
could do, He can do now. Some things, however, at one time were in the
nature of possibility, whilst they were yet to be done, which now fall
short of the nature of possibility, when they have been done. So is
God said not to be able to do them, because they themselves cannot be
done.
Reply to Objection 3: God can remove all corruption of the mind and
body from a woman who has fallen; but the fact that she had been
corrupt cannot be removed from her; as also is it impossible that the
fact of having sinned or having lost charity thereby can be removed
from the sinner.

---

If God himself cannot go against the causality principle, how can we,
poor
physicists? ;)

See http://www.ccel.org/a/aquinas/summa/home.html for more.
Michele Simionato
Jul 18 '05 #255
Robin Becker <ro***@jessikat.fsnet.co.uk> wrote in message news:
This is a bit too meta-physical, but then much of modern physics is like
that.


That's an incorrect view of much of modern physics. The fault is to
general public books which generates a false impression :-(

Michele
Jul 18 '05 #256
mi**@pitt.edu (Michele Simionato) wrote:
A good rule of the thumb is "never believe anything you read and you don't
understand". Sometimes, you should not believe even what you think you
understand ...


In Scientific American (I think it was the may 2003 issue) I read
something about parallel universes. One idea goes like this (adapted
to make it fit my brain).

Suppose you're sitting in a chair in the middle of a virtual 2X2X2
cube. Next imagine a cube filled with protons (or some even smaller
particles) as tightly as possible. The difference between this cube
and the cube you are sitting in is that in your cube some of the
protons are absent. The cubes could possibly be represented by Python
long integers [1], where the full cube would be a long with all bits
set to one and different cubes would have some zero bits at
corresponding positions.

There can not be more different cubes than 2**(number of protons per
cube) so in an infinite universe (or even in a big enough universe) at
some distance from you a cube identical to the one you are occupying
would exist, or else one would need a very good reason why the cube
you are occupying is unique.

Anton

[1] How many protons would fit inside a 2x2x2 meter cube is left as an
exercise for the readers
Jul 18 '05 #257
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:
OK - so why is it not possible to detect the superposition of that
cat? Why is the experiment still considered a thought experiment only?


As I understand it, you *could* perform the experiment, modulo problems
with the society for the protection of animals. Actually, those experiments
*have been* performed a number of times and are still performed. Of course,
they don't use cats, but they call "cats" the wave packets used in the
experiments.

Quantum mechanics (any interpretation of it) will predict that if you repeat
the experiment many times, you will kill the cat 50% of times. Now, if you
really do the experiment, you will really get this rate of success or
failure (depending if you like cats or not), since quantum mechanics
works.

The point and the crux of the discussion is: "what happens to
the cat *before* opening the box?" This is a matter of principle,
so the experiment is a thought experiment; thought experiment
does not mean it cannot be realized (it's the same for Einstein's
elevator experiment, the basis for the equivalence principle).

Now, according to Bohr's interpretation
the question simply does not make sense: I don't know anything about
the cat if I do not observe it. It does not make sense to ask if it is
alive or dead: the only thing that matters is that the cat will be dead
50% of times when I open the box, and dead the other 50%.
Common sense says that the cat is alive or dead independently from the
fact that I observe it or not. This is called realism. BTW, I am sure
you are already familiar with the concept, but let me be verbose.

The orthodox quantum mechanics interpretation is NOT realistic: it
does not assume anything about the state of the cat prior to observation.
In this line of thinking, few centuries ago the Bishop Berkeley asked
to himself something like this: what happens to a tree when I don't look
at it? Am I *really* sure that the tree is still there? What if a evil
devil makes the tree disappear when I don't look at it, and reappear
when I look at it? At the end Berkeley solved the paradox by saying
that the reality is real because of God: He is watching all the trees
all the time, so we may be sure that trees are still there even if
we are not watching them.

In the last couple of centuries we have
lost our faith in God (fortunately/unfortunately) so now there is
nobody watching the cat inside the box. For this reason we don't
know if it is alive or dead, and we say that it is in a superposition
state. What happens when we open the box (i.e. when we perform the
measurament) we don't know; for sure it is something bizarre which
we model with the wave function collapse argument, but there is
no doubt that the argument is weak and should be replaced by
something better. We use it for lack of better alternatives (the
MWI is not considered a good alternative by the majority of
physicists).

My point is that this is an INTERPRETATION: depending on your religious
belief you may find the realistic interpretation more or less appealing
(Einstein was against it).

This is not a point of Physics: both interpretation say that when we
measure we will get 50% of dead cats, and actually we get that. This
is Physics; the rest is speculation. You may adhere to the realist
interpretation, but in this case you must loose the property of
locality, and most people are so unhappy with this, that they
prefer to renonce to realism (there is a theorem that you cannot
get both realism and locality for free, and also experiments on
Bell's unequalities, so this is "for sure").

What it is really interesting it to understand how measurement works,
how to pass from microscopic to macroscopic, how to give a better
description of what happens behind the wave function collapse.
This is an *hard* job, but there is an active line of research on
*these* issues and I don't think we have lost hope. At the end, a theory
providing *new* verifiable predictions will emerge. A theory
providing the *same* predictions but a different interpretation
will not have any success, since results are more important than
interpretations (at least, to most physicists). We are more pragmatic and
less academic than other academic people, I think ;)

I should have got the argument right, but please remember that
these topics are typically not taught in courses, since they are not
considered very relevant, and I have last studied Berkeley's argument
more than 15 years ago, so I may remember uncorrectly. Here I am giving
my opinion and I don't have an autoritative reference on the subject now.
So, my word should be taken "cum grano salis". On the other hand,
the word of everybody should be taken "cum grano salis" ;)

HTH,

Michele Simionato
Jul 18 '05 #258
On Tue, 28 Oct 2003 15:49:04 +0100, an***@vredegoor.doge.nl (Anton
Vredegoor) wrote:
mi**@pitt.edu (Michele Simionato) wrote:
A good rule of the thumb is "never believe anything you read and you don't
understand". Sometimes, you should not believe even what you think you
understand ...


In Scientific American (I think it was the may 2003 issue) I read
something about parallel universes. One idea goes like this (adapted
to make it fit my brain).

Suppose you're sitting in a chair in the middle of a virtual 2X2X2
cube. Next imagine a cube filled with protons (or some even smaller
particles) as tightly as possible. The difference between this cube
and the cube you are sitting in is that in your cube some of the
protons are absent. The cubes could possibly be represented by Python
long integers [1], where the full cube would be a long with all bits
set to one and different cubes would have some zero bits at
corresponding positions.

There can not be more different cubes than 2**(number of protons per
cube) so in an infinite universe (or even in a big enough universe) at
some distance from you a cube identical to the one you are occupying
would exist, or else one would need a very good reason why the cube
you are occupying is unique.


That has little to do with the many worlds interpretation of waveform
collapse. These 'universes' do not interact with each other in the way
that superpositions of particles do.

Actually, if you imagine that cube full of protons again, according to
quantum theory many of those protons may be in superposed states. That
is, a single proton may be in several states, including being in
several positions.

How many states may a single proton have within that cube? Well, it
isn't just the number of combinations of possible superpositions of
states of protons. For example, the state where two superpositions
happen to be identical (indistinguishable state - think of polynomials
with repeating roots) but other superpositions have measurably
different states would have measurably different consequences to that
where there is only one occurence of each uniquely recognisable
superposed state for that proton. In fact, you can have an infinitite
number of states for that cube of space with only one proton in that
space by simply counting all possible sets of superposed states for
the proton.

Which means that the number of possible states of matter is not finite
even if we ignore the states where some superposed states of a
particular proton are inside the cube while others are outside it.

I hope you also realise that your cube, defined in space only, is not
sufficient to define a parallel universe. Each proton has momentum as
well as position, and a proton may well have an infinite number of
possible kinetic energy levels. The cube thus becomes a hypercube with
time as one dimension, and each proton is represented by a curve - not
just a single point position. How many curves can exist in that
hypercube, even for a single proton?

Even ignoring momentum, what about quantum uncertainty - just because
the current state of that cube is identical (and ignoring any
influence from surrounding cubes of space) the future states of
different instances of the supposedly parallel universe may play out
differently. We may well discover in future a more general model which
recovers perfect determinism, but given current evidence we cannot
assume that.

Finally, how can you assume that there is only a finite number of
possible positions of a proton within that space? A quick look at
relativity tells us that space is not like graph paper. Spacetime
itself may have different shapes, dependent on matter outside as well
as inside that cube.
There are, of course, important theories which measure the amount of
information in any region of spacetime - and the amount of information
turns out surprisingly small - but I am not convinced that the measure
is of all information in that region as opposed to, for instance, all
information that is accessible to an outside observer. Certainly there
is something rather odd going on which cannot be explained by proton
counting.
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #259
On 28 Oct 2003 08:32:16 -0800, mi**@pitt.edu (Michele Simionato)
wrote:
The point and the crux of the discussion is: "what happens to
the cat *before* opening the box?" This is a matter of principle,
so the experiment is a thought experiment; thought experiment
does not mean it cannot be realized (it's the same for Einstein's
elevator experiment, the basis for the equivalence principle).


Not exactly. When we look at superpositions of subatomic particles,
there are observable artifacts of the interactions between
superpositions - the interference patterns. Without those
interactions, the theory of superpositions would be pointless as there
would be no effects of superposition to observe - the theory would
have no predictive or explanatory power.

My point is that the cat is superposed in the same way as the
subatomic particle, and yet we are unable to observe any artifact of
that superposition. *All* we can see is a single state resulting from
the waveform collapse when we observe the cat, but this is
emphatically not the case with subatomic particles where we can
observe artifacts of the superposition itself.

This has been answered, however, by the simple fact that interference
patterns are the only observable artifact of superpositions - it would
be rather hard to fire a cat through two narrow slits simultaneously,
it would also be rather hard to observe the resulting interference
pattern, and certainly the animal protection charities would be pretty
upset with you if you tried it ;-)
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #260
jj*@pobox.com (John J. Lee) wrote in message news:<87************@pobox.com>...
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".


How does MWI generalize to quantum field theory? If it does not generalize,
as I will bet it is the case (I would know otherwise) it explain much *less*
than the standard interpretation. Between two theories, one explaining
more and one explaining less, we prefer the one that explains more.
It is as simple as that and it explain why MWI is not popular at all
outside philosophical circles. I will gladly admit that the orthodox
theory is not perfect, but it is the best we have, at least according
to most physicists. There are always exceptions (Deusch): please do
mistake the exceptions for the norm.
Michele Simionato
Jul 18 '05 #261
mi**@pitt.edu (Michele Simionato) writes:
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news: [...] In the last couple of centuries we have
lost our faith in God (fortunately/unfortunately) so now there is [...]

Again, I think the statistics are against you, Michele! Most people
on the planet believe in a God. Most Americans believe in a God.
Dunno for sure about Europeans, but I'd be surprised if it were
otherwise.

My point is that this is an INTERPRETATION: depending on your religious
belief you may find the realistic interpretation more or less appealing
(Einstein was against it).

This is not a point of Physics: both interpretation say that when we
measure we will get 50% of dead cats, and actually we get that. This
is Physics; the rest is speculation. You may adhere to the realist
That way of thinking (instrumentalism) is seductive, but wrong. I
refer you to Deutsch's book again (getting repetetive, I know).

interpretation, but in this case you must loose the property of
locality, and most people are so unhappy with this, that they [...]

Not in the MWI (I'm extremely hazy on this point now, though :-( if I
ever did really understand it).

What it is really interesting it to understand how measurement works,
how to pass from microscopic to macroscopic, how to give a better
description of what happens behind the wave function collapse.
This is an *hard* job, but there is an active line of research on

[...]

It's rather easier if you accept the MWI, of course.
John
Jul 18 '05 #262
mi**@pitt.edu (Michele Simionato) writes:
jj*@pobox.com (John J. Lee) wrote in message news:<87************@pobox.com>... [...] How does MWI generalize to quantum field theory? If it does not generalize,
as I will bet it is the case (I would know otherwise) it explain much *less*
See Q14 of:

http://www.hedweb.com/manworld.htm

(MWI FAQ, which also gives details of that popularity contest I
mentioned. I think their wording on this point ("metatheory") is
perhaps a bit misleading, mind.)

than the standard interpretation. Between two theories, one explaining
more and one explaining less, we prefer the one that explains more.
It is as simple as that and it explain why MWI is not popular at all
outside philosophical circles. I will gladly admit that the orthodox
theory is not perfect, but it is the best we have, at least according
to most physicists. There are always exceptions (Deusch): please do
mistake the exceptions for the norm.


<sigh> I've already answered those points.
John
Jul 18 '05 #263
an***@vredegoor.doge.nl (Anton Vredegoor) wrote in message news:<bn**********@news.hccnet.nl>...
mi**@pitt.edu (Michele Simionato) wrote:
A good rule of the thumb is "never believe anything you read and you don't
understand". Sometimes, you should not believe even what you think you
understand ...


In Scientific American (I think it was the may 2003 issue) I read
something about parallel universes. One idea goes like this (adapted
to make it fit my brain).

Suppose you're sitting in a chair in the middle of a virtual 2X2X2
cube. Next imagine a cube filled with protons (or some even smaller
particles) as tightly as possible. The difference between this cube
and the cube you are sitting in is that in your cube some of the
protons are absent. The cubes could possibly be represented by Python
long integers [1], where the full cube would be a long with all bits
set to one and different cubes would have some zero bits at
corresponding positions.

There can not be more different cubes than 2**(number of protons per
cube) so in an infinite universe (or even in a big enough universe) at
some distance from you a cube identical to the one you are occupying
would exist, or else one would need a very good reason why the cube
you are occupying is unique.

Anton

[1] How many protons would fit inside a 2x2x2 meter cube is left as an
exercise for the readers


<G>
are we allowed to assume that the protons will compress into true cubes,
or that they remain true spheres?
</G>

(no, i'm not about to do the arithmetic)
robert
Jul 18 '05 #264
jj*@pobox.com (John J. Lee) wrote in message news:<87************@pobox.com>...
[...snip most of a huge list of arguments from authority...]
No, no, please don't get me wrong!
The whole point of my post was an encouragement to DO NOT believe
authority (including mine, of course). If I wrote something like
"I have a background in Theoretical Physics with ten years of
research experience ... etc. etc." this has not to be interpreted
as "Ah, I am so much better than you".

Of course not. You should not believe me because of authority,
nor you should not take my word for granted. Also, you are perfectly
free to adhere to Deutsch views, I am not trying to convince you.
But when I see a statement such as

"It's a bit of an embarrassment to Physics that some physicists
apparently still believe in the Copenhagen interpretation"

I simply cannot let it pass.

I do think this statement is strongly misleading and I cannot let
people in this newsgroup to get a false impression abot Physics. False in
my own view, of course. But here is the reason why I pointed out my
background in Physics: my background is very relevant in this context
(how popular is MWI between physicist). For sociological questions like
this, first hand experience does matter: I do know from the inside what
physicists really do; and there is a big difference between reading
books and being a physicist. So, I think I was perfectly right in
stressing my background before presenting my observations. You may
believe me or not, but at least you know that I talk for direct
experience.
Well, perhaps the sample consisting of "Physicists Michele Simionato
knows" has *some* merit <wink>
How may physicists do you know, personally? Not offence intented, but
first hand experience does matter, as I said. Not only I know lot of
physicists (I was at conferences with big names such as Mandelbrot,
Higgs, Seiberg ... etc.) but, more importantly, I do know the
opinion of the other physicist about those "great names".
You will be surprised how much irrespectful it is.
but the single serious survey of
"great and good" Physicists' opinions I have read about (sorry, can't
give reference... but I think it must have been either in one of those
flaky books by Frank Tipler, or in Deutsch's "The Fabric of Reality"
that I read about it) revealed that a large majority believed
(essentially -- obviously there are subtleties) in the MWI. Not sure
when that was carried out either, but it was back when Feynman was
still alive.
Who is making argument from authority now?
Precisely, and IMHO (as well as, if you want argument from authority,
rather cleverer folks, like Deutsch)


Arguments from authority have the problem that you can always choose
your preferred authority, so you are always right. I would not qualify
Deutsch or Tipler as "great" physicists, but this is beside the point.
I would qualify Albert Einstein as a "great" physicist. He didn't believe
the Copenhagen interpretation either; he believed in the hidden variables theory.
Such a theory has been proved to be wrong by real world experiments,
so he was wrong. Everybody (unless he is Dutch) can be wrong, so please
let's stop the arguments from authority. The argument from personal
experience is different in the sense that at least I am not invoking
somebody else to support my views.

Finally: notice that I didn't make any specific claim against MWI
in this posts, I limited myself to few sociological observations
and a few facts. An objective fact is the number of conferences
about MWI theory. Please, look at
http://www.physics.umd.edu/robot/confer/confmenu.html
and compute yourself the percentage of conferences about MWI
(including or not including the ones mixed with philosophy
conferences).

Also, please believe that physicist are no stupid, so there must
be some reason why there is relatively little active research about MWI.
BTW, you may interpret this statistical observation as a disguised
argument from authority and you may be right, but it is so difficult
to get rid of arguments from authority! ;)

I write all this for the benefit of c.l.py regulars, anybody has
the right to follow Deutsch's views, but they should not be presented
as dominating in the physics community ("some physicists
apparently still believe in the Copenhagen interpretation").

Michele Simionato
Jul 18 '05 #265
an***@vredegoor.doge.nl (Anton Vredegoor) wrote in message news:<bn**********@news.hccnet.nl>...
In Scientific American (I think it was the may 2003 issue) I read
something about parallel universes. One idea goes like this (adapted
to make it fit my brain).

Suppose you're sitting in a chair in the middle of a virtual 2X2X2
cube. Next imagine a cube filled with protons (or some even smaller
particles) as tightly as possible. The difference between this cube
and the cube you are sitting in is that in your cube some of the
protons are absent. The cubes could possibly be represented by Python
long integers [1], where the full cube would be a long with all bits
set to one and different cubes would have some zero bits at
corresponding positions.

There can not be more different cubes than 2**(number of protons per
cube) so in an infinite universe (or even in a big enough universe) at
some distance from you a cube identical to the one you are occupying
would exist, or else one would need a very good reason why the cube
you are occupying is unique.

Anton


I fail to see the argument, sorry. OTOH, I have few observations
that may be of interest (even if way off topics, as all of this
most interesting thread ;)

According to the inflationary paradigm (which is a serious
paradigm with observational support) we live in a small
portion of the entire Universe. That means the following:

1. the observable Universe, i.e. the causally connected part of the
Universe, is next to nothing with respect to the full Universe;

2. there could be infinitely many other words in the outer part of the
Universe;

3. the cosmological horizon is expanding with time, so those others
worlds will become available to us if we wait a few billions years;

4. we still live in an inflationary epoch, so the rate of expansion
of the universe will increase with time.

I would consider all these points (including the last one, only discovered
2-3 years ago) serious science. This means, they may be wrong, but they are
serious, based on some experimental/observational evidence.

So, I would say that serious science (at least serious according to me ;)
can accept many worlds in the inflationary context: actually it predicts
them. The real point is that there is only ONE universe that matters, i.e.
the casually connected part of the Universe where we live: the rest of
the Universe cannot influence us in any way. Nevertheless, it influenced
us in the far far away past (when we were in causal contact with a much
bigger part of the Universe) and it will influence us in the far far
away future, as the cosmological horizon increases.

Nowadays, the causal radius of the Universe is something like 45 billions
of light years (notice that the Universe is 15 billions of years old,
but the causal radius is not 15 billions of light years, since the concept
of "distance" is rather tricky in general relativity), so it contains
only 10^52 cubes of 2x2x2 meters. I strongly disbelieve that in some of
the other cubes there is a copy of myself replying to a copy of Anton
Vredegoor in a copy of c.l.py.

10^52 is a very little number as compared to infinity!

Moreover: reasoning about infinity is tricky. An infinite Universe does not
necessarely means that all possible combinations are available. The
set of even numbers is infinite, but does not contain any copy of the
number "2", nor it contains any odd number, by definition.
It is quite risky to make any statement about infinity, unless you are
talking about a very specific kind of infinite that we have under mathematical
control, such as Cantor theory of transfinite sets. So, be careful:
the infinity of mathematicians and physicists is quite different
from the infinity of the philosopher.
Michele Simionato
Jul 18 '05 #266
jj*@pobox.com (John J. Lee) wrote in message news:<87************@pobox.com>...
mi**@pitt.edu (Michele Simionato) writes:
In the last couple of centuries we have
lost our faith in God (fortunately/unfortunately) so now there is

[...]

Again, I think the statistics are against you, Michele! Most people
on the planet believe in a God. Most Americans believe in a God.
Dunno for sure about Europeans, but I'd be surprised if it were
otherwise.


My fault, I was too concise and I didn't express clearly what I meant.
Here is what I had in mind when I wrote "In the last couple of centuries
we have lost our faith in God ...":

1. the "we" has to be qualified as "we scientists and educated people";
2. the "lost our faith in God" has to be interpreted as "lost our faith
in God as a way of scientific explanation of reality".

Look at the context: I was talking about Berkeley, who had the possibility to
recur to God as a way of ensuring realism; this possibility is (fortunately/
unfortunately) precluded to modern science, just in the same sense that we
cannot invoke angels as an explanation for the motion of planets.

I was by no means implying that most of people (or most of modern scientists)
are unbelievers. This would simply be not true. I meant that there is a
consensus in the modern scientific community that we cannot use God as a
way of scientific explanation. Things were different at the time of Berkeley.

Also I had in the back of my mind the idea that in the Germany of the
twenties, after the World War I, there was quite a luck of faith in
the traditional concept of God (see books such as "Demian" by Herman
Hesse, for instance) and it is not strange, in that historical/philosophical
context that somebody came out with concepts like the indetermination principle
or the refusal of realism. I would not expect those concepts coming out
in the context of victorian U.K., for instance. Not that I am advocating
the view that Physics is determinated by the sociological context, but
certainly it is influenced by it. Vice versa, the sociological context can
be influenced by Physics (expecially after we made the bomb).
Michele Simionato
Jul 18 '05 #267
mi**@pitt.edu (Michele Simionato) writes:
jj*@pobox.com (John J. Lee) wrote in message news:<87************@pobox.com>...
[...snip most of a huge list of arguments from authority...] [...]
But when I see a statement such as

"It's a bit of an embarrassment to Physics that some physicists
apparently still believe in the Copenhagen interpretation"

I simply cannot let it pass.

I do think this statement is strongly misleading and I cannot let
people in this newsgroup to get a false impression abot Physics. False in
my own view, of course. But here is the reason why I pointed out my
background in Physics: my background is very relevant in this context
(how popular is MWI between physicist). For sociological questions like
this, first hand experience does matter: I do know from the inside what
Well, we simply disagree about the epistemology of this, and the
statement of mine that you quote just reflects that disagreement. A
discussion of popularity can't clear that up.

[...] but the single serious survey of
"great and good" Physicists' opinions I have read about (sorry, can't
give reference... but I think it must have been either in one of those
flaky books by Frank Tipler, or in Deutsch's "The Fabric of Reality"
that I read about it) revealed that a large majority believed
(essentially -- obviously there are subtleties) in the MWI. Not sure
when that was carried out either, but it was back when Feynman was
still alive.


Who is making argument from authority now?


<cough, splutter> I was responding to you! Am I to be reprimanded for
responding to your anecdotes with an actual survey?

Precisely, and IMHO (as well as, if you want argument from authority,
rather cleverer folks, like Deutsch)


Arguments from authority have the problem that you can always choose
your preferred authority, so you are always right. I would not qualify

[...]

<gasp> How *dare* you aim this at me, when *YOU* posted an enormous
list of arguments from authority, and *I* told you off for doing so?
Even in the section you quote, I explictly labelled my parenthesised
comment as argument from authority (hence invalid). The cheek of it
*ASTOUNDS* me! :-)

I hereby give up on this thread in disgust, this'll be my last post
(the rest of the NG will be very pleased to hear ;-).

Finally: notice that I didn't make any specific claim against MWI
in this posts, I limited myself to few sociological observations
Yes, I was QUITE well aware of that! ;-)

and a few facts. An objective fact is the number of conferences
about MWI theory. Please, look at
http://www.physics.umd.edu/robot/confer/confmenu.html
and compute yourself the percentage of conferences about MWI
(including or not including the ones mixed with philosophy
conferences).
If you read my posts, you would know that I *agree* with you that the
fact that this is still an issue is unfortunate and takes time away
from more important issues of new Physics.

Also, please believe that physicist are no stupid, so there must
be some reason why there is relatively little active research about MWI.
Yep, because there's probably not much to be done on MWI in itself. I
agree with you there.

I write all this for the benefit of c.l.py regulars, anybody has
the right to follow Deutsch's views, but they should not be presented
as dominating in the physics community ("some physicists
apparently still believe in the Copenhagen interpretation").


OK, I give you that, I shouldn't have implied that that the overall
number (or fraction) of CI-believers or non-MWI-believers was small
(though I certainly don't know whether it's a majority or not -- and
I'm afraid your anecdotes don't persuade me that you do, either).
Amongst jobbing Physicists (rather than the "great and good" of that
survey), I would *guess* the fraction of CI-believers or people who've
never really thought about it is much higher (partly because some
parts of the 'front-line' of Physics, cosmology and quantum
computation in particular, tend to rub the inadequacy of CI in your
face).
John
Jul 18 '05 #268
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:<ff********************************@4ax.com>. ..
Not exactly. When we look at superpositions of subatomic particles,
there are observable artifacts of the interactions between
superpositions - the interference patterns. Without those
interactions, the theory of superpositions would be pointless as there
would be no effects of superposition to observe - the theory would
have no predictive or explanatory power.

My point is that the cat is superposed in the same way as the
subatomic particle, and yet we are unable to observe any artifact of
that superposition. *All* we can see is a single state resulting from
the waveform collapse when we observe the cat, but this is
emphatically not the case with subatomic particles where we can
observe artifacts of the superposition itself.


There is no such a big difference between the Scroedinger's cat experiment
and the narrow slits experiment:
| |
| |
A | S
P | |
-> | |
B |
| |
| |

The particle P passes through one of the slits A,B and ends its life on the
screen S, producing a spot. Getting the spor corresponds to opening the box in
the cat experiment. If you repeat the experiment many times
with many particles, the distribution of the spots is an interference
pattern. But if you perform the experiment with a single particle, then
you have 50% of probability of getting the spot in the upper side of the
screen, and 50% in the lower side (assuming a symmetrical experimental
disposition). This corresponds to have the cat 50% of times alive
and 50% of times dead when we open the box. Having only seen the spot in S,
it does not make sense to ask whether the particle passed through A or through
B, exactly in the same sense that it does not make sense to ask if the cat
is dead or alive before opening the box (this according to the
orthodox interpretation). If you watch to see if the particle really passes
for A you necessarely perturb the system. For instance, you can close the
slit B, and make sure that the particle passes trought A, but then the
interference disappear.
When the particle reach S and you get the spot, then the collapse
of the wave function happens. It is less spectacular than opening
the box, but in principle it is the same operation. I will not
claim that the collapse is understood, not that it is an easy
task to understand it :-(

Michele Simionato
Jul 18 '05 #269
On 29 Oct 2003 05:23:26 -0800, mi**@pitt.edu (Michele Simionato)
wrote:
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:<ff********************************@4ax.com>. ..
Not exactly. When we look at superpositions of subatomic particles,
there are observable artifacts of the interactions between
superpositions - the interference patterns. Without those
interactions, the theory of superpositions would be pointless as there
would be no effects of superposition to observe - the theory would
have no predictive or explanatory power.

My point is that the cat is superposed in the same way as the
subatomic particle, and yet we are unable to observe any artifact of
that superposition. *All* we can see is a single state resulting from
the waveform collapse when we observe the cat, but this is
emphatically not the case with subatomic particles where we can
observe artifacts of the superposition itself.


There is no such a big difference between the Scroedinger's cat experiment
and the narrow slits experiment:
| |
| |
A | S
P | |
-> | |
B |
| |
| |

The particle P passes through one of the slits A,B and ends its life on the
screen S, producing a spot. Getting the spor corresponds to opening the box in
the cat experiment. If you repeat the experiment many times
with many particles, the distribution of the spots is an interference
pattern. But if you perform the experiment with a single particle, then
you have 50% of probability of getting the spot in the upper side of the
screen, and 50% in the lower side (assuming a symmetrical experimental
disposition). This corresponds to have the cat 50% of times alive
and 50% of times dead when we open the box. Having only seen the spot in S,
it does not make sense to ask whether the particle passed through A or through
B, exactly in the same sense that it does not make sense to ask if the cat
is dead or alive before opening the box (this according to the
orthodox interpretation). If you watch to see if the particle really passes
for A you necessarely perturb the system. For instance, you can close the
slit B, and make sure that the particle passes trought A, but then the
interference disappear.
When the particle reach S and you get the spot, then the collapse
of the wave function happens. It is less spectacular than opening
the box, but in principle it is the same operation. I will not
claim that the collapse is understood, not that it is an easy
task to understand it :-(


OK, but there is still an artifact. In order for a sufficiently large
number of repetitions to build an interference pattern, the points on
S cannot be simple projections of P through A or B.

With the cat, the there are two possible final states - either the cat
is alive or dead - essentially the 'projections' of the initial
radioactive decay through the cause-and-effect chain with the detector
and poison.

There is still a clear artifact at the microscopic scale (the point
detected on S is NOT a simple projection through either A or B)
whereas no such artifact can be detected at the macroscopic scale (the
cat ends up either alive or dead, just as it would without any quantum
considerations).

I don't claim to understand quantum theory by any means, but I do know
that in principle if there were no artifacts of quantum effects no
sane human would have invented them.

So why don't we find cats that are half-dead and half-alive (between
the projections of A and B), or cats which are more dead than dead
(further to the A side than the projection of A)?

Perhaps cats simply don't have a particle/wave duality issue to worry
about.
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #270
jj*@pobox.com (John J. Lee) wrote in message news:<87************@pobox.com>...
mi**@pitt.edu (Michele Simionato) writes:
OK, I give you that, I shouldn't have implied that that the overall
number (or fraction) of CI-believers or non-MWI-believers was small
(though I certainly don't know whether it's a majority or not -- and
I'm afraid your anecdotes don't persuade me that you do, either).
Amongst jobbing Physicists (rather than the "great and good" of that
survey), I would *guess* the fraction of CI-believers or people who've
never really thought about it is much higher (partly because some
parts of the 'front-line' of Physics, cosmology and quantum
computation in particular, tend to rub the inadequacy of CI in your
face).


Please, take a look at my publication list (it is enough to search for
my name at http://www.slac.stanford.edu/spires/hep/) and you will see that
I have published research papers in the domain of early Universe cosmology.
In my experience, the beliefs of people in the field are different
from what you say.
I prefer not to comment on the "jobbing physicist" part.

Michele Simionato
Jul 18 '05 #271
mi**@pitt.edu (Michele Simionato) writes:
[...]
I prefer not to comment on the "jobbing physicist" part.


Hmm, just in case of any misunderstanding: I wasn't trying to belittle
your work as a Physicist by using that phrase, Michele. It was meant
light-heartedly, and wasn't even meant as a description of you in
particular (I've never read any of your Physics work, after all).
John
Jul 18 '05 #272
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:
<snip some argument I would agree>
Perhaps cats simply don't have a particle/wave duality issue to worry
about.


I have got the impression (please correct me if I misread your posts) that
you are invoking the argument "cats are macroscopic objects, so their
ondulatory nature does not matter at all, whereas electrons are
microscopic, so they ondulatory nature does matter a lot."

This kind of arguments are based on the de Broglie wavelenght concept and
are perfectly fine. Nevertheless, I would like to make clear (probably
it is already clear to you) that quantum effects are by no means
confined to the microscopic realm. We cannot say "okay, quantum is
bizarre, but it does not effect me, it affects only a little world
that I will never see". That's not true. We see macroscopic effects of
the quantum nature of reality all the time. Take for instance
conduction theory. When you turn on your computer, electron flow
through a copper cable from the electric power plant to your house.
Any modern theory of conduction is formulated as a
(non-relativistic) quantum field theory of an electron gas
interacting with a lattice of copper atoms. From the microscopic
theory you get macroscopic concepts, for instance you may determine
the resistivity as a function of the temperature. The classical
Drude's model has long past as a good enough explanation of
conductivity. Think also to superconductivity and superfluidity:
these are spectacular examples of microscopic quantum effects
affecting macroscopic quantities.
Finally, the most extreme example: quantum fluctuations
during the inflationary era, when the entire observable universe
has a microscopic size, are finally responsible for the density
fluctuations at the origin of galaxies formation. Moreover, we
observe effects of these fluctuations in the cosmic background
radiation, i.e. from phothons coming from the most extreme
distance in the Universe, phothons that travelled from billions
and billions of light years. Now, that's macroscopic!
Michele
Jul 18 '05 #273
On 29 Oct 2003 23:26:05 -0800, mi**@pitt.edu (Michele Simionato)
wrote:
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:
<snip some argument I would agree>
Perhaps cats simply don't have a particle/wave duality issue to worry
about.
I have got the impression (please correct me if I misread your posts) that
you are invoking the argument "cats are macroscopic objects, so their
ondulatory nature does not matter at all, whereas electrons are
microscopic, so they ondulatory nature does matter a lot."


That is *far* from what I am saying.

I find some explanations of superposition and decoherence difficult to
believe *because* they seem to differentiate between the microscopic
and macroscopic scales. MWI is one - the appearance is that
macroscopic objects in superposition get a different universe for each
superposed state (because there is no visible artifact of the
superposition - the observer is only in one universe) whereas for
microscopic objects in superposition there is no different universe
(as there are clear artifacts of the superposition, showing that the
superposed states interacted and thus existed in the same universe at
the same time).

I equally find the 'conscious mind has special role as observer'
hypothesis hard to accept as we have ample evidence that the universe
existed for billions of years before there were any conscious minds
that we know of. The evidence suggests that conscious minds exist
within the universe as an arrangement of matter subject to the same
laws as any other arrangement of matter.

In both cases, there is no issue of proof or logic involved. It's more
a matter of credibility - and with the conscious mind concept in
particular, of explanatory value. As far as science has studied the
mind so far all the findings show it to be an arrangement of matter
following the same laws of physics and chemistry that any other
arrangement of matter follows. There is no sign of an outside agency
creating unexplainable artifacts in the brains functioning. And if
there is no role for a thing outside of the brain to be generating
consciousness - if the consciousness we experience is a product of the
brain - then what role does this other consciousness have?

While I have a tendency to confuse his name (I think I called him
Penfold earlier, though what Dangermouse' sidekick has to do with this
I really can't say!), I prefer Penrose' theory where the microscopic
and macroscopic really are different - not because they follow
different rules, but because the time that a superposition can survive
is inversely related to the uncertainty it creates in space-time. Have
a lot of mass in substantially different states (e.g. a cat both alive
and dead, or for that matter a vial of poison both broken and intact)
and the superposition can only survive for a tiny portion of a second.

I'm not sure if this is the same Penrose who speculates that
superposition of brain states is important to creating consciousness.
It would be odd if it is, of course, as a brain is clearly
macroscopic. But then he could mean something else - many
superpositions of particles within the brain. As long as each created
superposition only a small local uncertainty in space time (ie no
substantial 'hotspots' of superposition), this accumulation of
microscopic superpositions could be consistent - though to be honest I
seriously doubt it.

As should be clear, my understanding of the specifics of quantum
theory is extremely limited - but my understanding of general
scientific principles isn't too bad. That is why I earlier pointed out
that maybe the MWI wouldn't cause me such a problem if it was
expressed in some other way - after all, most current theory is so
abstract that the explanations should be taken as metaphors rather
than reality anyway.
This kind of arguments are based on the de Broglie wavelenght concept and
are perfectly fine. Nevertheless, I would like to make clear (probably
it is already clear to you) that quantum effects are by no means
confined to the microscopic realm. We cannot say "okay, quantum is
bizarre, but it does not effect me, it affects only a little world
that I will never see". That's not true. We see macroscopic effects of
the quantum nature of reality all the time.
No problem with that, but we are seeing microscopic effects en masse
rather than macroscopic effects - something rather different, in my
mind, to a cat being both alive and dead at the same time. For
example...
Take for instance
conduction theory. When you turn on your computer, electron flow
through a copper cable from the electric power plant to your house.
Any modern theory of conduction is formulated as a
(non-relativistic) quantum field theory of an electron gas
interacting with a lattice of copper atoms. From the microscopic
theory you get macroscopic concepts, for instance you may determine
the resistivity as a function of the temperature. The classical
Drude's model has long past as a good enough explanation of
conductivity. Think also to superconductivity and superfluidity:
these are spectacular examples of microscopic quantum effects
affecting macroscopic quantities.
Of course. But none of these requires a macroscopic object to be
superposed. It may require many microscopic objects to have been
superposed, over and over again (I really don't know how, or even if,
superposition is really involved in these effects - but let me argue
the principle anyway) - but that isn't the same thing. Taking Penrose'
theory again, each individual superposition only creates a small local
uncertainty in spacetime. As long as the many separate superpositions
are spread out in space and time, there will be no particular
'hotspots' where superposition would brake down. In fact, any
coincidental hotspots of uncertainty would accelerate decorence of
superpositions in that region and thus act as a stabilising or
limiting factor in setting the amount of superposition that can occur
in any region.

I would suggest that this limiting thing would be a useful artifact to
look for - or at least some useful artifact might be suggested by the
idea - that could be tested for to proove or disproove the theory.
This limiting effect wasn't mentioned in the article, BTW - maybe
Penrose hasn't thought of it (he proposed to look for artifacts of a
single superposition which cannot be measured using current
technology).

Maybe superfluids would be the place to look for that artifact. Maybe
there is something in the shells of electrons around a nucleus - I'd
certainly expect quantum wierdness there.

But of course I wouldn't have a clue what kind of artifact to look
for, as my understanding is strictly limited to the 'I've read new
scientist on occasion' level.
Finally, the most extreme example: quantum fluctuations
during the inflationary era, when the entire observable universe
has a microscopic size, are finally responsible for the density
fluctuations at the origin of galaxies formation. Moreover, we
observe effects of these fluctuations in the cosmic background
radiation, i.e. from phothons coming from the most extreme
distance in the Universe, phothons that travelled from billions
and billions of light years. Now, that's macroscopic!


Of course, but the quantum effects are not particularly interesting in
that case. Or rather they are to cosmology, but not as far as I can
see to understanding quantum theory. It's a bit like looking at an
image from an electron microscope and claiming that an atom is several
mm wide - the artifact that you are observing has simply been scaled
up relative to the process that created that artifact. The effects
when they occured were on the microscopic scale - only the artifacts
are macroscopic.
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #274
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote:
particular, of explanatory value. As far as science has studied the
mind so far all the findings show it to be an arrangement of matter
following the same laws of physics and chemistry that any other
arrangement of matter follows. There is no sign of an outside agency
creating unexplainable artifacts in the brains functioning. And if
there is no role for a thing outside of the brain to be generating
consciousness - if the consciousness we experience is a product of the
brain - then what role does this other consciousness have?
The more territory modern science covers, the more it becomes clear
that the known parts of the universe are only a small part of what is
"out there". So "objectively" science gains more knowledge, but
relatively speaking (seeing it as a percentage of that what is
currently known to be not known, but knowable in principle) science is
loosing ground fast. Also an even greater area of the universe is
supposed to exist that we will not even have a chance *ever* to know
anything about.

Trough out the centuries there has been evidence placing humanity
firmly *not* in the center of the universe. First the earth was proven
to rotate around the sun and not the other way around, next our sun
was not in the center of the galaxy and so on.

Maybe now it is time to accept the fact that all the things we know
taken together are only a small fraction of what can be known, and
even more that that fraction is not even in a central position in the
larger universe of the knowable, and that the knowable is just
disappearingly small compared to the great abyss of the unknowable
where everything is embedded in.

How come then that the sciences have been so uncanningly effective
given that they are such an arbitrary choice within the knowable? The
answer is of course that there are a lot of other possible sciences,
completely unrelated to our own that would have been just as effective
as -or even more effective than- our current sciences, had they been
pursued with equal persistence during the same amount of time over a
lot of generations.

The effectiveness of the current natural sciences is a perceptual
artifact caused by our biased history. From a lot of different
directions messages are coming in now, all saying more or less the
same: "If asking certain questions, one gets answers to these
questions in a certain way, but if asking different questions one gets
different answers, sometimes even contradicting the answers to the
other questions".

This might seem mystic or strange but one can see these things
everywhere, if one asks that kind of questions :-)

One example would be the role the observer plays in quantum mechanics,
but something closer to a programmer would be the way static or
dynamic typing influence the way one thinks about designing a computer
program. A static typist is like someone removing superfluous material
in order to expose the statue hidden inside the marble, while a
dynamic typist would be comparable to someone taking some clay,
forming it into a shape and baking it into a fixed form only at the
last possible moment. These ways of designing things are both valid
(and there are infinitely more other ways to do it) but they lead to
completely different expectations about the design of computer
programs.

In a certain sense all science reduces the world to a view of it that
leaves out more than that it describes, but that doesn't preclude it
being effective. For a last example, what about the mathematics of
curved surfaces? Sciences have had most of their successes using
computations based on straight lines, and only recently the power of
curves is discovered as being equal or more predictive than linear
approaches.

[..]
As should be clear, my understanding of the specifics of quantum
theory is extremely limited - but my understanding of general
scientific principles isn't too bad. That is why I earlier pointed out
that maybe the MWI wouldn't cause me such a problem if it was
expressed in some other way - after all, most current theory is so
abstract that the explanations should be taken as metaphors rather
than reality anyway.


Abstractness doesn't preclude effectiveness, but to try to use
abstractions to understand the world is foolish since it doesn't work
the other way around. It's a many to one mapping, as in plotting a
sinus function on an xy-plane and not being able to find a
x-coordinate to a certain y-coordinate, while at he same time being
perfectly able to predict an y-coordinate if given an x-coordinate.

Anton

Jul 18 '05 #275
Anton Vredegoor" <an***@vredegoor.doge.nl>:
The more territory modern science covers, the more it becomes clear
that the known parts of the universe are only a small part of what is
"out there".
But as Stephen pointed out, the new things we find are new
in terms of arrangement but still following the same laws of physics
we see here on Earth. (There *may* be some slight changes in
cosmological constants over the last dozen billion years, but I
haven't followed that subject.) These arrangements may be
beyond our ability to model well, but there's little to suggest
that in principle they couldn't be. (Eg, QCD could be used to
model the weather on Jupiter, if only we had a currently almost
inconceivably powerful computer. Running Python. ;)
So "objectively" science gains more knowledge, but
relatively speaking (seeing it as a percentage of that what is
currently known to be not known, but knowable in principle) science is
loosing ground fast. Also an even greater area of the universe is
supposed to exist that we will not even have a chance *ever* to know
anything about.
That's a strange measure: what we know vs. what we know we
don't know. Consider physics back in the late 1800s. They could
write equations for many aspects of electricity and magnetism, but
there were problems, like the 'ultraviolet catastrophe'. Did they
consider those only minor gaps in knowledge or huge, gaping chasms
best stuck in a corner and ignored?

Is the gap between QCD and general relativity as big? Hmmmm...
Trough out the centuries there has been evidence placing humanity
firmly *not* in the center of the universe. First the earth was proven
to rotate around the sun and not the other way around, next our sun
was not in the center of the galaxy and so on.
You use this as an argument for insignificance. I use it to show
that the idea of "center of" is a meaningless term. If I want, I can
consider my house as the center of the universe. I can still make
predictions about the motion of the planets, and they will be
exactly as accurate as using a sun-centered model. The only
difference is that my equations will be a bit more complicated.
Maybe now it is time to accept the fact that all the things we know
taken together are only a small fraction of what can be known, and
even more that that fraction is not even in a central position in the
larger universe of the knowable, and that the knowable is just
disappearingly small compared to the great abyss of the unknowable
where everything is embedded in.
Why? I mean, it's true, but it seems that some knowledge is
more useful than others. It's true because even if there were
a quadrillion people, each one would be different, with a unique
arrangement of thoughts and perceptions and a unique bit of
knowledge unknowable to you.
How come then that the sciences have been so uncanningly effective
given that they are such an arbitrary choice within the knowable? The
answer is of course that there are a lot of other possible sciences,
completely unrelated to our own that would have been just as effective
as -or even more effective than- our current sciences, had they been
pursued with equal persistence during the same amount of time over a
lot of generations.
I don't follow your argument that this occurs "of course."

It's not for a dearth of ideas. Humans did try other possible
sciences over the last few millenia. Despite centuries of effort,
alchemy never became more than a descriptive science, and
despite millenia of attempts, animal sacrifices never improved
crop yields, and reading goat entrails didn't yield any better
weather predictions.

On the other hand, there are different but equivalent ways to
express known physics. For example, Hamiltonian and Newtonian
mechanics, or matrix vs. wave forms of classical quantum mechanics.
These are alternative ways to express the same physics, and some
are easier to use for a given problem than another. Just like a
sun-centered system is easier for some calculations than a "my house"
centered one.

On the third hand, there are new theoretical models, like string
theory, which are different than the models we use. But they are
not "completely unrelated" and yield our standard models given
suitable approximations.

On the fourth hand, Wolfram argues that cellular automata
provide such a new way of doing science as you argue. But
my intuition (brainw^Wtrained as it is by the current scientific
viewpoint) doesn't agree.
The effectiveness of the current natural sciences is a perceptual
artifact caused by our biased history. From a lot of different
directions messages are coming in now, all saying more or less the
same: "If asking certain questions, one gets answers to these
questions in a certain way, but if asking different questions one gets
different answers, sometimes even contradicting the answers to the
other questions".

This might seem mystic or strange but one can see these things
everywhere, if one asks that kind of questions :-)
Or it means that asking those questions is meaningless. What's
the charge of an electron? The bare point charge is surrounded
by a swarm of virtual particles, each with its own swarm. If you
work it out using higher and higher levels of approximation you'll
end up with different, non-converging answers, and if you continue
it onwards you'll get infinite energies. But given a fixed
approximation you'll find you can make predictions just fine, and
using mathematical tricks like renormalization, the inifinities cancel.

For a simpler case .. what is the center of the universe? All locations
are equally correct. Is it mystic then that there can be multiple
different answers or is simply that the question isn't well defined?
One example would be the role the observer plays in quantum mechanics,
but something closer to a programmer would be the way static or
dynamic typing influence the way one thinks about designing a computer
program.
The latter argument was an analogy that the tools (formalisms) affect
the shape of science. With that I have no disagreement. The science
we do now is affected by the existance of computers. But that's
because no one without computers would work on, say, fluid dynamics
simulations requiring trillions of calculations. It's not because the
science is fundamentally different.

And I don't see how the reference to QM affects the argument. Then
again, I've no problems living in a collapsing wave function.
In a certain sense all science reduces the world to a view of it that
leaves out more than that it describes, but that doesn't preclude it
being effective. For a last example, what about the mathematics of
curved surfaces? Sciences have had most of their successes using
computations based on straight lines, and only recently the power of
curves is discovered as being equal or more predictive than linear
approaches.
Yes, a model is a reduced representation. The orbit of Mars can be
predicted pretty well without knowing the location of every rock on
it surface. The argument is that knowing more of the details (and
having the ability to do the additional calculations) only improves the
accuracy. And much of the training in science is in learning how to
make those approximations and recognize what is interesting in the
morass of details.

As for "straight lines". I don't follow your meaning. Orbits have
been treated as curves since, well, since before Ptolomy (who used
circles) or since Kepler (using ellipses), and Newton was using
parabolas for trajectories in the 1600s, and Einstein described
curved space-time a century ago.
Abstractness doesn't preclude effectiveness, but to try to use
abstractions to understand the world is foolish since it doesn't work
the other way around.


You have a strange definition of "effectiveness." I think a science
is effective when it helps understand the world.

The other solution is to know everything about everything, and, well,
I don't know about you but my brain is finite. While I can remember
a few abstractions, I am not omnipotent.

Andrew
da***@dalkescientific.com
Jul 18 '05 #276
Andrew Dalke wrote:
Anton Vredegoor" <an***@vredegoor.doge.nl>:
The more territory modern science covers, the more it becomes clear
that the known parts of the universe are only a small part of what is
"out there".
But as Stephen pointed out, the new things we find are new
in terms of arrangement but still following the same laws of physics
we see here on Earth. (There *may* be some slight changes in
cosmological constants over the last dozen billion years, but I
haven't followed that subject.) These arrangements may be
beyond our ability to model well, but there's little to suggest
that in principle they couldn't be. (Eg, QCD could be used to
model the weather on Jupiter, if only we had a currently almost
inconceivably powerful computer. Running Python. ;)


Probably not even with Python! :-(
Weather (3D fluid dynamics) is chaotic both here on Earth and on Jupiter.
As Dr. Lorenz established when he tried to model Earth's weather, prediction
of future events based on past behavior (deterministic modeling) is not
possible with chaotic events. Current weather models predicting global or
regional temperatures 50 years from now obtain those results by careful
choices of initial conditions and assumptions. In a chaotic system
changing the inputs by even a small fractional amount causes wild swings in
the output, but for deterministic models fractional changes on the input
produce predictable outputs.
So "objectively" science gains more knowledge, but
relatively speaking (seeing it as a percentage of that what is
currently known to be not known, but knowable in principle) science is
loosing ground fast. Also an even greater area of the universe is
supposed to exist that we will not even have a chance *ever* to know
anything about.

Exactly. Even worse, the various peripherals of Physics and Math are
getting so esoteric that scholars in those areas are losing their ability
to communicate to each other. It is almost like casting chicken entrails.

That's a strange measure: what we know vs. what we know we
don't know. Consider physics back in the late 1800s. They could
write equations for many aspects of electricity and magnetism, but
there were problems, like the 'ultraviolet catastrophe'. Did they
consider those only minor gaps in knowledge or huge, gaping chasms
best stuck in a corner and ignored?

Is the gap between QCD and general relativity as big? Hmmmm...
Trough out the centuries there has been evidence placing humanity
firmly *not* in the center of the universe. First the earth was proven
to rotate around the sun and not the other way around, next our sun
was not in the center of the galaxy and so on.
You use this as an argument for insignificance. I use it to show
that the idea of "center of" is a meaningless term. If I want, I can
consider my house as the center of the universe. I can still make
predictions about the motion of the planets, and they will be
exactly as accurate as using a sun-centered model. The only
difference is that my equations will be a bit more complicated.
Maybe now it is time to accept the fact that all the things we know
taken together are only a small fraction of what can be known, and
even more that that fraction is not even in a central position in the
larger universe of the knowable, and that the knowable is just
disappearingly small compared to the great abyss of the unknowable
where everything is embedded in.


Why? I mean, it's true, but it seems that some knowledge is
more useful than others. It's true because even if there were
a quadrillion people, each one would be different, with a unique
arrangement of thoughts and perceptions and a unique bit of
knowledge unknowable to you.
How come then that the sciences have been so uncanningly effective
given that they are such an arbitrary choice within the knowable? The
answer is of course that there are a lot of other possible sciences,
completely unrelated to our own that would have been just as effective
as -or even more effective than- our current sciences, had they been
pursued with equal persistence during the same amount of time over a
lot of generations.


I don't follow your argument that this occurs "of course."

It's not for a dearth of ideas. Humans did try other possible
sciences over the last few millenia. Despite centuries of effort,
alchemy never became more than a descriptive science, and
despite millenia of attempts, animal sacrifices never improved
crop yields, and reading goat entrails didn't yield any better
weather predictions.

On the other hand, there are different but equivalent ways to
express known physics. For example, Hamiltonian and Newtonian
mechanics, or matrix vs. wave forms of classical quantum mechanics.
These are alternative ways to express the same physics, and some
are easier to use for a given problem than another. Just like a
sun-centered system is easier for some calculations than a "my house"
centered one.

On the third hand, there are new theoretical models, like string
theory, which are different than the models we use. But they are
not "completely unrelated" and yield our standard models given
suitable approximations.

On the fourth hand, Wolfram argues that cellular automata
provide such a new way of doing science as you argue. But
my intuition (brainw^Wtrained as it is by the current scientific
viewpoint) doesn't agree.
The effectiveness of the current natural sciences is a perceptual
artifact caused by our biased history. From a lot of different
directions messages are coming in now, all saying more or less the
same: "If asking certain questions, one gets answers to these
questions in a certain way, but if asking different questions one gets
different answers, sometimes even contradicting the answers to the
other questions".

This might seem mystic or strange but one can see these things
everywhere, if one asks that kind of questions :-)


Or it means that asking those questions is meaningless. What's
the charge of an electron? The bare point charge is surrounded
by a swarm of virtual particles, each with its own swarm. If you
work it out using higher and higher levels of approximation you'll
end up with different, non-converging answers, and if you continue
it onwards you'll get infinite energies. But given a fixed
approximation you'll find you can make predictions just fine, and
using mathematical tricks like renormalization, the inifinities cancel.


The charge of an Electron is a case in point. Okkam's Razor is the
justification for adopting unitary charges and disregarding fractional
charges. But, who justifies Okkam's Razor?


For a simpler case .. what is the center of the universe? All locations
are equally correct. Is it mystic then that there can be multiple
different answers or is simply that the question isn't well defined?
"All locations are equally correct" depends on your base assumptions about
the Cosmological Constant, and a few other constants. Event Stephen
Hawkings, in "A Brief History of Time" mentions the admixture of philsophy
in determining the value of A in Einstein's Metric.

One example would be the role the observer plays in quantum mechanics,
but something closer to a programmer would be the way static or
dynamic typing influence the way one thinks about designing a computer
program.


The latter argument was an analogy that the tools (formalisms) affect
the shape of science. With that I have no disagreement. The science
we do now is affected by the existance of computers. But that's
because no one without computers would work on, say, fluid dynamics
simulations requiring trillions of calculations. It's not because the
science is fundamentally different.

And I don't see how the reference to QM affects the argument. Then
again, I've no problems living in a collapsing wave function.
In a certain sense all science reduces the world to a view of it that
leaves out more than that it describes, but that doesn't preclude it
being effective. For a last example, what about the mathematics of
curved surfaces? Sciences have had most of their successes using
computations based on straight lines, and only recently the power of
curves is discovered as being equal or more predictive than linear
approaches.


Yes, a model is a reduced representation. The orbit of Mars can be
predicted pretty well without knowing the location of every rock on
it surface. The argument is that knowing more of the details (and
having the ability to do the additional calculations) only improves the
accuracy. And much of the training in science is in learning how to
make those approximations and recognize what is interesting in the
morass of details.

As for "straight lines". I don't follow your meaning. Orbits have
been treated as curves since, well, since before Ptolomy (who used
circles) or since Kepler (using ellipses), and Newton was using
parabolas for trajectories in the 1600s, and Einstein described
curved space-time a century ago.
Abstractness doesn't preclude effectiveness, but to try to use
abstractions to understand the world is foolish since it doesn't work
the other way around.


You have a strange definition of "effectiveness." I think a science
is effective when it helps understand the world.

The other solution is to know everything about everything, and, well,
I don't know about you but my brain is finite. While I can remember
a few abstractions, I am not omnipotent.

Andrew
da***@dalkescientific.com


--

-
GrayGeek
Jul 18 '05 #277
On Sat, 01 Nov 2003 16:28:09 +0100, an***@vredegoor.doge.nl (Anton
Vredegoor) wrote:
As should be clear, my understanding of the specifics of quantum
theory is extremely limited - but my understanding of general
scientific principles isn't too bad. That is why I earlier pointed out
that maybe the MWI wouldn't cause me such a problem if it was
expressed in some other way - after all, most current theory is so
abstract that the explanations should be taken as metaphors rather
than reality anyway.


Abstractness doesn't preclude effectiveness, but to try to use
abstractions to understand the world is foolish since it doesn't work
the other way around. It's a many to one mapping, as in plotting a
sinus function on an xy-plane and not being able to find a
x-coordinate to a certain y-coordinate, while at he same time being
perfectly able to predict an y-coordinate if given an x-coordinate.


Oh dear, here we go again...

The human brain simply doesn't have the 'vocabulary' to handle
concepts which are outside of our direct experience. 'Gravity' we can
deal with as it is in our everyday direct experience. Space-time
curvature, OTOH, is not - it is an abstract concept (relative to what
we perceive directly) and we can only understand it by relating it to
things that we do understand - metaphor being a very common way of
doing so.

So in the case of space-time curvature, for instance, 'curvature'
itself is a metaphor. It relates to the geometry of a non-Euclidean
space (or rather space-time, in this case). The intuitive meaning of
the word 'curve' relates to shape - in mathematical terms, a locus of
points in space. But the concept of non-Euclidian curvature is not
intended to suggest that the non-Euclidian space exists within some
higher order space. Sometimes it does (e.g. the non-Euclidean space
defined by the surface of the Earth exists within the 3D space of,
well, space ;-) ) but equally, often it does not.

So far as we know, space-time is 'curved' but does not exist in a
higher-order space - it just happens to have a non-Euclidean geometry.
And as that geometry is entirely defined (so far as we currently know)
by the content of space-time (gravity), there is no need to
hypothesise a higher level space. In fact it may not be possible to
create appropriate space-time 'shapes' within any higher order space -
it is certainly possible to define non-Euclidian 2D surfaces that
cannot be implemented using a real surface shape in flat 3D space.

You can point out that there is a specialist definition of the word
'curve' which relates specifically to non-Euclidian geometry, and deny
any connection to earlier meanings of the word 'curve' or to peoples
intuitive sense of what a curve is, but that would be pretty abstruse.
The simple fact is that that word has considerable explanatory power -
it presents an abstract concept in terms that make sense to people,
and which allows them to visualise the concept. That is why the term
'curve' was selected when non-Euclidian geometry was first defined and
studied and, despite the later specialist definition of the word, it
remains relevant - it is still how people understand the geometry of
non-Euclidean spaces and it is still how people understand the concept
of space-time curvature. The real phenomena described by the term
'space-time curvature' simply don't exist in peoples direct
experience.
I have just been through the same point (ad nauseum) in an e-mail
discussion. Yet I can't see what is controversial about my words.
Current theory is abstract (relative to what we can percieve) and we
simply don't have the right vocabulary (both in language, and within
the mind) to represent the concepts involved. We can invent words to
solve the language problem, of course, but at some point we have to
explain what the new words mean.

Thus, as I said, "most current theory is so abstract that the
explanations should be taken as metaphors rather than reality anyway."

The point being that different metaphors may equally have been chosen
to explain the same models - presumably emphasising different aspects
of them - and such explanations may work better for people who can't
connect with the existing explanations. The model would still be the
same, though, just as it remains the same even if you describe it in a
language other than English. The terminology changes, but not the
model.
I get the feeling that there must be some 'ism' relating to metaphor
in physics, and people are jumping to the conclusion that I'm selling
that 'ism'. But seriously, whatever a 'metaphorianist' may be, I am
not one of them.

Read very carefully, and you will note that I said the EXPLANATIONS
should be taken as metaphors - NOT the models themselves.

And yes, a model is distinct from the real thing that it models, but
that is a rather uninteresting point and not one that I would normally
bother commenting on.

As I know from the e-mail discussion that this point can be serially
misunderstood no matter how I state it, I will make one final attempt
to clarify my point as far as I am able and that is it - I am bored to
death with the issue, and have no interest in continuing it. So here
it is...

I don't deny that, for instance, quarks are real. They are just as
real as protons, atoms, molecules, bricks and galaxy clusters. The
fact that the concept of a quark is more than a little abstract
(relative to what humans can experience directly) does not stop it
being real.

The word "curvature" in "space-time curvature" is a metaphor, however.
Space-time does not exist as a locus of points in some higher-order
space. But space-time really does have a non-Euclidean geometry, which
is easier to understand if you visualise it in terms of curvature.
Hence the common ball-on-a-rubber-sheet analogy (the rubber sheet
being an easily understood 2D curved 'space' within a 3D space).

At no time did I say that relativity is a metaphor. The model
described by relativity is real (within limits, as with any model), as
is clear from the fact that it has been proven.

But if you believe you can describe relativity (or equally, quantum
mechanics) in entirely literal terms - at all, let alone in a way that
people can understand it - I'll be very *very* impressed.
I hope that is sufficient to lay that issue to rest, but in any case I
cannot be bothered with it any more. I *HAVE* asked several people IRL
what they thought I meant by that half scentence in case I was going
nuts, and it was clear that they all understood what I meant. This is
not, in other words, an Asperger syndrome based misunderstanding.

I stand by what I said 100%, but I can't write a book explaining every
half-scentence I write. Life is too short.
With appols, BTW, to those who have written rather large books dealing
with my misunderstandings and thus helped me to understand how they
arise. But I really don't think my AS is the problem here.
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #278
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:<uh********************************@4ax.com>. ..
On 29 Oct 2003 23:26:05 -0800, mi**@pitt.edu (Michele Simionato)
wrote:
I have got the impression (please correct me if I misread your posts) that
you are invoking the argument "cats are macroscopic objects, so their
ondulatory nature does not matter at all, whereas electrons are
microscopic, so they ondulatory nature does matter a lot."
That is *far* from what I am saying.

Oops, sorry! I was not sure about your point: sometimes I have difficulties
in understanding what are you saying, but when I understand it, I usually agree
with you ;)
The evidence suggests that conscious minds exist
within the universe as an arrangement of matter subject to the same
laws as any other arrangement of matter.
I think that mind is a an arrangement of matter, too; nevertheless,
I strongly doubt that we will ever be able to understand it. Incidentally,
I am also quite skeptical about IA claims.
I prefer Penrose' theory
I read a Penrose's book book years ago: if I remember correctly, he
was skeptical about AI (that was ok). However, at some point there was
an argument of this kind: we don't understand mind, we don't understand
quantum gravity, therefore they must be related. (?)
most current theory is so
abstract that the explanations should be taken as metaphors rather
than reality anyway.
True.
No problem with that, but we are seeing microscopic effects en masse
rather than macroscopic effects - something rather different, in my
mind, to a cat being both alive and dead at the same time. The effects
when they occured were on the microscopic scale - only the artifacts
are macroscopic.


I have nothing against what you say in the rest of your post, but let me
make a comment on these points, which I think is important and may be of
interest for the other readers of this wonderfully off-topics thread.

According to the old school of Physics, there is a large distinction
between fundamental (somewhat microscopic) Physics and
non-fundamental (somewhat macroscopic) Physics. The idea
is that once you know the fundamental Physics, you may in principle
derive all the rest (not only Physics, but also Chemistry, Biology,
Medicine, and every science in principle). This point of view, the
reductionism, has never been popular between chemists of biologists, of
course, but it was quite popular between fundamental physicists with
a large hubrys.

Now, things are changing. Nowadays most people agree with the effective
field theory point of view. According to the effective field theory approach,
the fundamental (microscopic) theory is not so important. Actually, for
the description of most phenomena it is mostly irrelevant. The point is
that macroscopic phenomena (here I have in mind (super)conductivity or
superfluidity) are NOT simply microscopic effects en mass: and in
certain circumstances they do NOT depend at all from the microscopic theory.

These ideas come from the study of critical phenomena (mostly in condensed
matter physics) where the understanding of the macroscopic is (fortunately)
completely unrelated from the understanding of the microscopic: we don't need
to know the "true" theory or a detailed description of the material we
are studying, if we are near a critical point. In this situation it is enough to
know an effective field theory which can explain all the phenomena we can see
given a finite experimental precision, even if it is not microscopically
correct. In critical phenomena the concept of universality came out: completely
different microscopical theories can give the *same* universal macroscopic
field theory. Actually, the only things that matter are the dimensionality
of the space-time and the symmetry group, all others details are irrelevant.

This point of view has become relevant at the fundamental Physics level too,
since nowadays most people regard the Standard Model of Particle Physics
(once regarded as "the" fundamental theory) as a low energy effective
theory of the "true" theory.

This means that even if it is not the full story, it explain the
99.99% of phenomena we can measure; moreover, it is extremely
difficult to see clear signatures of the "true" underlining theory.
The real theory can be string theory, can be loop quantum gravity,
can be a completely new theory, but for 99.99% of our experiments
only the effective theory matters. So, even if we knew perfectly
quantum gravity, this would not help at all in describing 99.99%
of elementary particle physics, since we would still need to
solve the quantum field theory.

And, for a similar reason, even if we knew everything about QCD,
we could not use it to describe the wheather of Jupiter (which is described
by a completely different effective theory) even if we had an ultra-powerful
Python-powered quantum computer ...

That's life, but it is more interesting this way ;)
Michele
Jul 18 '05 #279
"Andrew Dalke" <ad****@mindspring.com> wrote in message news:<Kd***************@newsread4.news.pas.earthli nk.net>...
On the fourth hand, Wolfram argues that cellular automata
provide such a new way of doing science as you argue. But
my intuition (brainw^Wtrained as it is by the current scientific
viewpoint) doesn't agree.
Me too ;)
Or it means that asking those questions is meaningless. What's
the charge of an electron? The bare point charge is surrounded
by a swarm of virtual particles, each with its own swarm. If you
work it out using higher and higher levels of approximation you'll
end up with different, non-converging answers, and if you continue
it onwards you'll get infinite energies. But given a fixed
approximation you'll find you can make predictions just fine, and
using mathematical tricks like renormalization, the inifinities cancel.
I would qualify myself as an expert on renormalization theory and I would
like to make an observation on how the approach to renormalization has
changed in recent years, since you raise the point.

At the beginning, quantum field theory was - more or less universally -
regarded as a fundamental theory. Fundamental theory means that asking
the right questions one must get the right answers.
Nowadays people are no more so optimistic.

Quantum field theory is hard: even if the perturbative renormalizability
properties you are referring to can be proved (BTW, now there are easy
proofs based on the effective field theory approach; I did my Ph.D. on
the subject) very very little can be said at the non-perturbative level.
Also, there are worrying indications. It may be very well possible that
QFT does not exists as a fundamental theory: i.e. it is not mathematically
consistent. For instance, perturbation theory in quantum electrodynamics
is probably not summable, so the sum of the renormalized series (even if
any single term is finite) is not finite. In practice, this is not bad,
since we can resum even non-summable series, but the price to pay to make
finite an infinite sum is to add an arbitrarity (technically, this
is completely unrelated to the infinities in renormalization, they
only seems similar). Now, one can prove that the arbitrarity is
extremely small and has no effect at all at our energy scales: but
in principle it seems that we cannot determine completely an observable,
even in quantum electrodynamics, due to an internal inconsistency of the
mathematical model.

Notice that what I am saying is by no means a definitive statement:
there are no conclusive proofs that the standard model is
mathematically inconsistent. But it could be. And it would not be
surprising at all, given the experience we have with simpler models.
The latter argument was an analogy that the tools (formalisms) affect
the shape of science. With that I have no disagreement. The science
we do now is affected by the existance of computers. But that's
because no one without computers would work on, say, fluid dynamics
simulations requiring trillions of calculations. It's not because the
science is fundamentally different.
Yes, and still a lot of science is done without computers. I never
used a computer for my scientific work, expect for writing my papers
in latex ;)
The other solution is to know everything about everything, and, well,
I don't know about you but my brain is finite. While I can remember
a few abstractions, I am not omnipotent.


we are not omnipotent nor omniscient, but still we may learn something ;)
Jul 18 '05 #280
On Sat, 01 Nov 2003 17:39:54 GMT, "Andrew Dalke"
<ad****@mindspring.com> wrote:
How come then that the sciences have been so uncanningly effective
given that they are such an arbitrary choice within the knowable? The
answer is of course that there are a lot of other possible sciences,
completely unrelated to our own that would have been just as effective
as -or even more effective than- our current sciences, had they been
pursued with equal persistence during the same amount of time over a
lot of generations.
I don't follow your argument that this occurs "of course."

It's not for a dearth of ideas. Humans did try other possible
sciences over the last few millenia. Despite centuries of effort,
alchemy never became more than a descriptive science, and
despite millenia of attempts, animal sacrifices never improved
crop yields, and reading goat entrails didn't yield any better
weather predictions.


;-)

Actually I missed this point in Antons post, being already primed to
be bugged by his last paragraph or two, so I will reply to it here.

The choice was not arbitrary by any stretch of the imagination. We
could not construct the models described by quantum mechanics or
relatively until we had a good understanding of classical mechanics.
We cannot percieve either quantum or relativistic effects directly, so
they could not be the earliest models. We needed sufficient scientific
understanding and practical technology to be able to observe these
effects at all.

I doubt anyone could form a sensible theory of electricity, for
instance, if the only experience of electricity that they could
perceive was of phenomena such as lightning and flames. No wonder it
was all blamed on angry gods!

And yes, even classical mechanics could not have been our first model
for simple commonsense reasons. How often, for instance, did ancient
Greeks get to observe objects moving through a frictionless
environment?
On the other hand, there are different but equivalent ways to
express known physics. For example, Hamiltonian and Newtonian
mechanics, or matrix vs. wave forms of classical quantum mechanics.
These are alternative ways to express the same physics, and some
are easier to use for a given problem than another. Just like a
sun-centered system is easier for some calculations than a "my house"
centered one.
Rather similar to the idea of using different metaphors to explain the
same model, though you are looking at maths rather than language.
On the third hand, there are new theoretical models, like string
theory, which are different than the models we use. But they are
not "completely unrelated" and yield our standard models given
suitable approximations.
Agreed. Just as quantum mechanics and relativity both yield a close
approximation of classical mechanics within certain limits, and just
as classical mechanics yields something close to 'intuitive physics'
within the limits of most peoples everyday lives.
On the fourth hand, Wolfram argues that cellular automata
provide such a new way of doing science as you argue. But
my intuition (brainw^Wtrained as it is by the current scientific
viewpoint) doesn't agree.
I just love the way that a guy who got rich selling software to do
fiddly maths jobs such as working with systems of differential
equations has suddenly decided that all that fiddly maths is
completely the wrong way to go ;-)

But even if, at some level, the universe is a cellular automata, I
don't see that meaning that the fiddly maths can be abandoned. The
fiddly maths is generally an artifact of removing detail in a sense,
after all - we use the formula for the entire path, for instance,
rather than listing all the points that make up the path. And the list
of points, like the list of states of the cells, lacks explanatory
power.
The effectiveness of the current natural sciences is a perceptual
artifact caused by our biased history. From a lot of different
directions messages are coming in now, all saying more or less the
same: "If asking certain questions, one gets answers to these
questions in a certain way, but if asking different questions one gets
different answers, sometimes even contradicting the answers to the
other questions".

This might seem mystic or strange but one can see these things
everywhere, if one asks that kind of questions :-)


Or it means that asking those questions is meaningless.


I wouldn't go so far. No model (at least none we have yet) is perfect,
so different models are bound to contradict each other - particularly
when you push them beyond their limits. Extrapolation is always less
reliable than interpolation, so it is best not to use a model to
extrapolate beyond the range where experiment has shown it to apply.

But there is clearly a baseline reality which these models are seeking
to approximate.

As I mentioned earlier, when a primitive person tries to understand
how your car works, the engine does not turn into a demon. The
technology based on our current scientific understanding works,
whatever you personally happen to believe.
For a simpler case .. what is the center of the universe? All locations
are equally correct. Is it mystic then that there can be multiple
different answers or is simply that the question isn't well defined?
Hmmm - I suppose this depends what you mean by center. If you mean
'origin' in the graph-plotting sense, then you are right, of course.

But my understanding is that the universe, so far as anyone can tell,
is either an infinite space or finite without bounds. In either case,
there is no such thing as a center.

I find the 'infinite' theory dubious - if the expansion rate has
remained finite since the big bang, then how can space have grown to
become infinite? The only way I can understand it is if space was
always infinite. That wouldn't necessarily mean it can't 'expand',
just as it isn't necessarily impossible to multiply infinity by two.

I guess 'expansion' relating to the universe is a metaphor too, really
- after all, the universe isn't an object within some other space. The
'expansion' is really just rewriting of the scale factors on the
dimension axes of the universe, I suppose. That being why the speed of
light isn't a problem in inflation - nothing is actually moving faster
than the speed of light, even though the distances between things is
expanding faster than the speed of light.

Hmmm - I wonder if 'expansion' or 'scale' is a continuous value in
space-time, like curvature? Well, I guess it must be really - just
write the model in those terms and hey presto - but what I mean, I
guess, is "is there a function that can define that 'scale' in terms
of local physics to explain things we don't currently have an
explanation for?".
One example would be the role the observer plays in quantum mechanics,
but something closer to a programmer would be the way static or
dynamic typing influence the way one thinks about designing a computer
program.


<snip>
And I don't see how the reference to QM affects the argument. Then
again, I've no problems living in a collapsing wave function.


I suspect this is the 'conscious mind has special role as observer'
thing again. And as has already stated, there are other explanations
of waveform collapse that don't require consciousness to take a
special role. Explanations that make more sense, as the observer never
had any control over how the waveform collapses - it is a mechanical
process that follows clearly defined non-mystical rules.
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #281
Me:
(Eg, QCD could be used to
model the weather on Jupiter, if only we had a currently almost
inconceivably powerful computer. Running Python. ;)
GrayGeek:
Weather (3D fluid dynamics) is chaotic both here on Earth and on Jupiter.
As Dr. Lorenz established when he tried to model Earth's weather, prediction of future events based on past behavior (deterministic modeling) is not
possible with chaotic events.
Weather is chaotic, but you misstate the conclusion. Short term predictions
are possible. After all, we do make weather predictions based on
simulations, and the "shot in the dark" horizon is getting more distant.
We're even getting reasonable models for hurricane track predictions.
Orbital mechanics for the major planets are also chaotic, it's just that the
time frame for problems well exceeds the life of the sun. (As I recall;
don't have a reference handy.)

Also, knowledge of history does help. Chaotic systems are still
subject to energy conservation and other physical laws, so
observations help predict which parts of phase space are accessible.
And if the system is only mildly chaotic (eg, Lyapunov exponent is
small enough) then an observation which is "close enough" to the
current state does help predict some of the future.
In a chaotic system changing the inputs by even a small fractional
amount causes wild swings in the output, but for deterministic
models fractional changes on the input produce predictable outputs.
To be nit-picky, that should be "... amount eventually causes arbitrary
differences in the output .. " (up to the constraints of phase space).
The two values could swing wildly but still track each other for some
time.
The charge of an Electron is a case in point. Okkam's Razor is the
justification for adopting unitary charges and disregarding fractional
charges. But, who justifies Okkam's Razor?
Quarks have partial charges, and solid state uses partial charges
for things like the fractional Hall effect.

The justification is that without Occam (or Ockham)'s razor
then there is no way to choose between theories with the same
ability to describe observed data.

In a simple case, consider
x y
-----
1 1
2 2
3 3
4 4
5 5

This can be modeled with y = x or with the osculating

y = 1*(x-2)*(x-3)*(x-4)*(x-5)/( (1-2)*(1-3)*(1-4)*(1-5) ) +
2*(x-1)*(x-3)*(x-4)*(x-5)/( (2-1)*(2-3)*(2-4)*(2-5) ) +
3*(x-1)*(x-2)*(x-4)*(x-5)/( (3-1)*(3-2)*(3-4)*(3-5) ) +
4*(x-1)*(x-2)*(x-3)*(x-5)/( (4-1)*(4-2)*(4-3)*(4-5) ) +
5*(x-1)*(x-2)*(x-3)*(x-4)/( (5-1)*(5-2)*(5-3)*(5-4) )

(Hope I got that all correct. BTW, I remember this as the
an osculating function, because it wobbles back and forth
so much it 'kisses' the actual function. However, the term
'osculating curve' appears to be something different and the
term 'osculating function' is almost never used. Pointers? )

Both describe the finite amount of data seen. Which
do you prefer, and why?
Me: For a simpler case .. what is the center of the universe? All locations
are equally correct. Is it mystic then that there can be multiple
different answers or is simply that the question isn't well defined?

"All locations are equally correct" depends on your base assumptions about
the Cosmological Constant, and a few other constants. Event Stephen
Hawkings, in "A Brief History of Time" mentions the admixture of philsophy
in determining the value of A in Einstein's Metric.


I was refering to my earlier statement that I could designate my house
as the center of the universe and still have all my calculations come
out correct. I somewhat overstepped that when I made the above
statement.

I looked in my copy of ABHoT but didn't see mention of "A".
It's been about a decade since I last looked at Wheeler, and I
never took a GR course, so I don't recognize the term. Web
searches don't find anything relevant. (Do you really mean
"a Lorentzian manifold whose Ricci tendor R_(ab) in the
coordinate basis is a constant scalar multiple of the metric
tensor g_(ab)."? Perhaps you mean the Robertson-Walker
metric, which appears to meet that definition. But there
doesn't appear to be an A term in the formulations I found.
Perhaps it's the a in the cosmic scale factor of the Friedmann
equation?)

How does the cosmological constant affect things? I don't
recall that having an implication on isotropy and homogeneity.

In any case, you are refering to the observed large-scale
isotropy and homogeneity of the universe. There is a bit in
ABHoT on that, but it's pre-COBE, and definitely pre-brane and
the statements of Hawking are more of a "this may explain things
but it's untested." Then again, that's about the current state of
the art too. ;)

So it's still pretty safe to say that my house is the center
of the universe.

Andrew
da***@dalkescientific.com
P.S.
When you quote someone else's post, please take care to
trim the paragraphs you are not responding to. That makes
it easier to find the text you added.
Jul 18 '05 #282
On 1 Nov 2003 22:19:11 -0800, mi**@pitt.edu (Michele Simionato) wrote:
most current theory is so
abstract that the explanations should be taken as metaphors rather
than reality anyway.
True.


Thank god - someone actually understood that bit!!!

Except you could have agreed with your own misunderstanding of what I
meant, I suppose - but lets agree to ignore that option ;-)
According to the old school of Physics, there is a large distinction
between fundamental (somewhat microscopic) Physics and
non-fundamental (somewhat macroscopic) Physics. The idea
is that once you know the fundamental Physics, you may in principle
derive all the rest (not only Physics, but also Chemistry, Biology,
Medicine, and every science in principle). This point of view, the
reductionism, has never been popular between chemists of biologists, of
course, but it was quite popular between fundamental physicists with
a large hubrys.
I think I understand what you mean.

I am aware of the idea, though I haven't really considered what it
implies. Certainly we haven't discovered any fundamental layer of
physics yet (AFAIK) and we may never do. And even if we do discover a
baseline level, it may be that we can never express the higher levels
deterministically in baseline level terms (as Goedel says, there are
relations that can never be proven or disproven - the incompleteness
theorem).

If forced to take a position, I would say that the key requirement is
that each model be consistent with all other models at all layers of
abstraction over the range where all are applicable. A higher level
layer may have features that cannot be derived from the lower level
layers, but they cannot contradict each other unless you go outside
the scope where one or more of the models is applicable.
Now, things are changing. Nowadays most people agree with the effective
field theory point of view. According to the effective field theory approach,
the fundamental (microscopic) theory is not so important. Actually, for
the description of most phenomena it is mostly irrelevant. The point is
that macroscopic phenomena (here I have in mind (super)conductivity or
superfluidity) are NOT simply microscopic effects en mass: and in
certain circumstances they do NOT depend at all from the microscopic theory.
OK - but if you are describing superfluidity as a single macroscopic
effect then you must describe it within a macroscopic framework. At
which point it has nothing to do with quantum effects because it isn't
within a quantum framework - it is just that the macroscopic
phenomenon called electricity (distinct from electrons moving en
masse) is not subject to the macroscopic phenomenon called resistance
(distinct from energy loss through the electomagnetic interactions
between electrons and atoms en masse) when the macroscopic phenomenon
called temperature (distinct from the kinetic energy of atoms en
masse) is sufficiently low.

There is nothing wrong with this per se - it is the limit of most
peoples (mine included) understanding of superconductivity - but it
has nothing to do with the framework of quantum mechanics.

The quantum framework may give an explanation, of sorts, for why
superconductivity occurs (or perhaps Goedel has put his veto on this)
but I do understand why explaining something less abstract to our
perceptions in terms of something even more abstract might seem
counterproductive ;-)
That's life, but it is more interesting this way ;)


Agreed ;-)
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #283
Stephen Horne:
We cannot percieve either quantum or relativistic effects directly, so
they could not be the earliest models.
[In general I agree with your post. Just some comments.]

What about superfluid helium?
And yes, even classical mechanics could not have been our first model
for simple commonsense reasons. How often, for instance, did ancient
Greeks get to observe objects moving through a frictionless
environment?
Every clear night.
I just love the way that a guy who got rich selling software to do
fiddly maths jobs such as working with systems of differential
equations has suddenly decided that all that fiddly maths is
completely the wrong way to go ;-)
Excepting that he spent 10 years on that book :)
But even if, at some level, the universe is a cellular automata, I
don't see that meaning that the fiddly maths can be abandoned.
I liked the scene in one of Brin's novels (from the Brightness Rift
trilogy). Alien civilizations are the result of a several billion years
old lineage. Nearly all knowledge is found in the Library.
Computer simulations are based on automata theory. But Earth
isn't part of the culture ("wolflings") and developed this bizarre
math using infinitesimals which was sophisticated enough to make
pen&paper(&abacus) predictions of certain events which were
hard to simulate.
I wouldn't go so far. No model (at least none we have yet) is perfect,
so different models are bound to contradict each other - particularly
when you push them beyond their limits.
True. But some questions are meaningless. "Wave or particle?"
"Where is the center of a black hole?" "What would happen if you
were driving at the speed of light and turned the headlights on?"
Hmmm - I suppose this depends what you mean by center. If you mean
'origin' in the graph-plotting sense, then you are right, of course.

But my understanding is that the universe, so far as anyone can tell,
is either an infinite space or finite without bounds. In either case,
there is no such thing as a center.
Michele is a better one for this topic. My point was just that many
different answers doesn't necessarily imply a mystic explanation.
I find the 'infinite' theory dubious - if the expansion rate has
remained finite since the big bang, then how can space have grown to
become infinite?


There's also the Oblers' paradox, but that also requires infinite time.

I read a popular account of "branes", membrane theory, which
was interesting. I don't know enough to describe it, other than
that the universe was created from high-dimensional membranes
hitting each other.

Andrew
da***@dalkescientific.com
Jul 18 '05 #284
On Sat, 01 Nov 2003 18:55:18 GMT, GrayGeek <jk********@FISHneb.rr.com>
wrote:
Weather (3D fluid dynamics) is chaotic both here on Earth and on Jupiter.
As Dr. Lorenz established when he tried to model Earth's weather, prediction
of future events based on past behavior (deterministic modeling) is not
possible with chaotic events. Current weather models predicting global or
regional temperatures 50 years from now obtain those results by careful
choices of initial conditions and assumptions. In a chaotic system
changing the inputs by even a small fractional amount causes wild swings in
the output, but for deterministic models fractional changes on the input
produce predictable outputs.


Very true for predicting weather, but the 50 years hence models are
predicting climate. That is a different layer of abstraction, and not
necessarily chaotic (at least on the same timescales) as shown by the
fact that the real world climate only changes relatively slowly -
despite some quite random inputs such as sunspot activity which have
nothing to do with chaos in the climate model.

Whether these models are actually accurate (or rather which, if any)
is, of course, a whole other question. I guess we'll find out in 50
years time ;-)
So "objectively" science gains more knowledge, but
relatively speaking (seeing it as a percentage of that what is
currently known to be not known, but knowable in principle) science is
loosing ground fast. Also an even greater area of the universe is
supposed to exist that we will not even have a chance *ever* to know
anything about.


Exactly. Even worse, the various peripherals of Physics and Math are
getting so esoteric that scholars in those areas are losing their ability
to communicate to each other. It is almost like casting chicken entrails.


There are just too many too abstract fields to be studied, I guess -
at some point, we'll need more specialists than the entire human
population!

Better start working on them AI systems ;-)
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #285
Michele Simionato:
I would qualify myself as an expert on renormalization theory and I would
like to make an observation on how the approach to renormalization has
changed in recent years, since you raise the point.
Feel free. I started a field theory course in '93 but didn't finish it
as I decided to do computational biophysics instead. So not only is
my knowledge dated but it wasn't strong to begin with.

(Plus, I was getting sick of SHOs ;)
only seems similar). Now, one can prove that the arbitrarity is
extremely small and has no effect at all at our energy scales: but
in principle it seems that we cannot determine completely an observable,
even in quantum electrodynamics, due to an internal inconsistency of the
mathematical model.
How small? Plank scale small?
Yes, and still a lot of science is done without computers. I never
used a computer for my scientific work, expect for writing my papers
in latex ;)


Whereas I went into computer simulations. Then again, I
wrote my first simulation program in ... 9th grade? .. for simulating
orbits, and tested it out by hand. Too bad I didn't know that I
should decrease the timestep, as my planets jumped all over the
place, and I didn't know about using a symplectic integrator,
nor about atan2, nor ...

Andrew
da***@dalkescientific.com
Jul 18 '05 #286
On Sun, 02 Nov 2003 08:36:09 GMT, "Andrew Dalke"
<ad****@mindspring.com> wrote:
Stephen Horne:
We cannot percieve either quantum or relativistic effects directly, so
they could not be the earliest models.
[In general I agree with your post. Just some comments.]

What about superfluid helium?


Superfluid helium is a macroscopic phenomenon - it may be explained in
terms of QM effects, but that doesn't make it a quantum effect in
itself any more than more everyday macroscopic effects (which can also
be described in QM terms). If superfluid helium is your only clue, it
will tell you no more about quantum effects than e.g. lightening tells
you about the properties of an electron.

Besides, you need the science and technology to achieve very low
temperatures before you can observe superfluid helium. It may be
pretty cold in the winter, but even so we don't often see superfluid
helium laying around ;-)
And yes, even classical mechanics could not have been our first model
for simple commonsense reasons. How often, for instance, did ancient
Greeks get to observe objects moving through a frictionless
environment?


Every clear night.


Yes, but they mostly thought the planets obeyed different laws to the
things that could see up close. Besides, with an Earth-centric model,
it is pretty hard to see the simple patterns of motion - and of course
even if they did, gravity is still confusing the issue. Don't forget
that it was actually quite a big leap of understanding when Newton
realised that the planets followed elliptical orbits because of the
same force that made apples fall from trees - it is only from the
perspective of having been told this since the age of 12 that it seems
obvious.

It was quite a revelation to discover that the physics of the cosmos
were actually the same physics we experience on the ground.
True. But some questions are meaningless. "Wave or particle?"
"Where is the center of a black hole?" "What would happen if you
were driving at the speed of light and turned the headlights on?"
Absolutely.

"Wave" and "particle" should be seen as metaphors, each describing a
subset of the properties of subatomic particles. The 'duality' is an
artifact of the metaphors.

The centre of a black hole exists, in a sense, but we can never
observe it because it is inside the event horizon, and as time itself
stops at the event horizon (from the perspective of any outside
observer) there is even good reason for claiming that the space inside
the event horizon doesn't exist.
Michele is a better one for this topic. My point was just that many
different answers doesn't necessarily imply a mystic explanation.
Yes, sorry - I was just following a random tangent.
I read a popular account of "branes", membrane theory, which
was interesting. I don't know enough to describe it, other than
that the universe was created from high-dimensional membranes
hitting each other.


I read a book about string and brane theory some time ago - I guess
possibly the same one, though it has vanished into book-borrowing
space as all the best books do so I can't tell you the title.

Lots of theory about possible geometries and topologies of many
dimensional space-time and how they could change from one another.
They didn't address the issue of how they could change at all, given
that time existed within the geometry rather than outside of it, and
for that among other reasons my impression was that it was a
fascinating read that nevertheless left me with no more clue than I
had to start with.

I would at least have appreciated a definition of supersymmetry,
rather than the usual 'its too abstract for your puny mind' copout.
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #287
On Sun, 02 Nov 2003 08:12:09 GMT, "Andrew Dalke"
<ad****@mindspring.com> wrote:
Orbital mechanics for the major planets are also chaotic, it's just that the
time frame for problems well exceeds the life of the sun. (As I recall;
don't have a reference handy.)


Are you sure?

I know that multi-object gravitational systems can be chaotic in
principle (and I believe that the orbits of some of Jupiters moons are
a case in point) but I thought the orbit of the planets around the sun
had been proven stable. Which implies that you needn't worry about
chaos unless you are worried about the minor deviations from the
idealised orbits - the idealised bit can be treated as constant, and
forms a very close approximation of reality no matter what timescale
you are working in.

It was one of the big successes of the Laplace transform, IIRC. But I
could be mistaken.
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #288
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:<4e********************************@4ax.com>. ..
I have just been through the same point (ad nauseum) in an e-mail
discussion. Yet I can't see what is controversial about my words.
Current theory is abstract (relative to what we can percieve) and we
simply don't have the right vocabulary (both in language, and within
the mind) to represent the concepts involved. We can invent words to
solve the language problem, of course, but at some point we have to
explain what the new words mean.

Thus, as I said, "most current theory is so abstract that the
explanations should be taken as metaphors rather than reality anyway."

The point being that different metaphors may equally have been chosen
to explain the same models - presumably emphasising different aspects
of them - and such explanations may work better for people who can't
connect with the existing explanations. The model would still be the
same, though, just as it remains the same even if you describe it in a
language other than English. The terminology changes, but not the
model.

Read very carefully, and you will note that I said the EXPLANATIONS
should be taken as metaphors - NOT the models themselves.


Dunno who was "attacking" you via e-mail, but FWIW, I fully support
your point of view and I am sure a lot of other people in science
would agree. The time where one could have a fully intuitive or
visual understanding of physical models is long past.

Nice discussion, BTW.

Michele
Jul 18 '05 #289
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote:
Oh dear, here we go again...
No, we don't :-)

[..]
I have just been through the same point (ad nauseum) in an e-mail
discussion. Yet I can't see what is controversial about my words.
Current theory is abstract (relative to what we can percieve) and we
simply don't have the right vocabulary (both in language, and within
the mind) to represent the concepts involved. We can invent words to
solve the language problem, of course, but at some point we have to
explain what the new words mean.


Probably this e-mail discussion -which I didn't have any part in- has
caused a lot of irritation, some of which has ended up on my plate,
but I just want to make clear it's not my piece of cake :-)

Anton
Jul 18 '05 #290
"Andrew Dalke" <ad****@mindspring.com> wrote in message news:<Yw****************@newsread4.news.pas.earthl ink.net>...
Michele Simionato wrote:

Now, one can prove that the arbitrarity is
extremely small and has no effect at all at our energy scales: but
in principle it seems that we cannot determine completely an observable,
even in quantum electrodynamics, due to an internal inconsistency of the
mathematical model.


How small? Plank scale small?


Actually it is much *smaller* than that: this is the reason why it is
not significant at all from a physical perspective. I was adopting there
a purely mathematical POV. In practice, only at absurdely high
energy scales, where certainly QED does not apply, the effect is relevant:
so physicist don't need to worry at all. The number I find in my Ph. D. thesis
(http://www.phyast.pitt.edu/~micheles/dott.ps, unfortunaly it is in
Italian since they give the freedom to write the dissertation in English
only the year after my graduation :-() is 10^227 GeV (!) BTW, it seems
too large now, I don't remember how I got it, but anyway I am sure the
number is much much larger than Plank scale (10^19 GeV).

In my post I was simply saying that there are issues of principle:
in practice quantum electrodynamics is the most successful physical
theory we ever had, with incredibly accurate predictions. No doubt
about that ;)
Jul 18 '05 #291
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:<15********************************@4ax.com>. ..
And yes, even classical mechanics could not have been our first model
for simple commonsense reasons. How often, for instance, did ancient
Greeks get to observe objects moving through a frictionless
environment?
It is a bit strange that Ancient Greeks did not discover classical
mechanics. Actually, entire books have been written on the subject,
trying to elucidate the economical and psychological mechanisms behind
this failure of the genial Greeks.
I find the 'infinite' theory dubious - if the expansion rate has
remained finite since the big bang, then how can space have grown to
become infinite? The only way I can understand it is if space was
always infinite. That wouldn't necessarily mean it can't 'expand',
just as it isn't necessarily impossible to multiply infinity by two.
You are perfectly right.

Notice that the expansion should not be taken to its
extreme consequences: at a certain scale the Universe enters in its
quantum gravity regime and we don't know nothing about its behavior
then. There are string-inspired models in which the so called Big Bang
does not exist and never happened. Many feel this perspective more
appealing.
I guess 'expansion' relating to the universe is a metaphor too, really
- after all, the universe isn't an object within some other space. The
'expansion' is really just rewriting of the scale factors on the
dimension axes of the universe, I suppose.
You are right.
That being why the speed of
light isn't a problem in inflation - nothing is actually moving faster
than the speed of light, even though the distances between things is
expanding faster than the speed of light.
That's pretty tricky. The maximum velocity for transmission of information
is always the speed of light, but depending on how you define distances
(which is tricky) you can get (apparently) speeds higher than that. I
find impossible to get an intuitive picture of how velocity compose
in the early Universe, even if I understand well the mathematics
involved (nothing more complicate than solving a differential equation
for the geodetic lines). It's the interpretation the real issue, as
always in modern Physics ;)

Also, a thing that confused me was Hubble law: if the speed of galaxies
increases with distance, one would naively think that at a certain moment
it will get higher than c. The solution of the paradox is that the linear
Hubble's law only works locally: there are corrections for far away
galaxies, so the maximum speed is always c.

Interested people should look at Weinberg's book on General Relativity,
the chapter on cosmological distances: however, be warned that it is
non-trivial!
Hmmm - I wonder if 'expansion' or 'scale' is a continuous value in
space-time, like curvature? Well, I guess it must be really - just
write the model in those terms and hey presto - but what I mean, I
guess, is "is there a function that can define that 'scale' in terms
of local physics to explain things we don't currently have an
explanation for?".
I do not understand what you are trying to say here.
And as has already stated, there are other explanations
of waveform collapse that don't require consciousness to take a
special role. Explanations that make more sense, as the observer never
had any control over how the waveform collapses - it is a mechanical
process that follows clearly defined non-mystical rules.


Agreed.

Michele Simionato
Jul 18 '05 #292
"Andrew Dalke" <ad****@mindspring.com> wrote in message news:<Zl****************@newsread4.news.pas.earthl ink.net>...
But my understanding is that the universe, so far as anyone can tell,
is either an infinite space or finite without bounds. In either case,
there is no such thing as a center.
Michele is a better one for this topic. My point was just that many
different answers doesn't necessarily imply a mystic explanation.


Since the Universe is homogenous and isotropic, every point has the
same right to be the center that any other point. In a more
mathematically inclined perspective, notice that in a curved
space the concept of center is tricky. For instance, what's
the center of the *surface* of the Earth? (yes, somebody could
say Washington DC, but I was talking about non-euclidean geometry,
not about politics ;)
I read a popular account of "branes", membrane theory, which
was interesting. I don't know enough to describe it


Then you know as much as the authors of the theory ;)

Michele Simionato
Jul 18 '05 #293
Stephen Horne:
Are you sure [about chaos in the solar system]? ... I thought the orbit of the planets around the sun
had been proven stable. Which implies that you needn't worry about
chaos unless you are worried about the minor deviations from the
idealised orbits - the idealised bit can be treated as constant, and
forms a very close approximation of reality no matter what timescale
you are working in.


Quoting from Ian Stewart's "The Problems of Mathematics" (c) 1987,
which is a very good book, and I encourage people to get a copy:

..could the other planets resonate with the Earth .. to make it collide
with Mars, or run off into the cold and empty interstellar wastes?
For imaginary solar systems simpler than ours, this kind of thing
can happen. Could it happen to us? In 1887 King Oscar II of
Sweden offered a prixe of 2,500 crowns for an answer.
..
As far as we know today, no closed form solutions exist [for the
general N body problem with N > 2]; at any rate, the general
behaviour is enormously complicated.... Lagrange and Laplace
between them did manage to show that the total departure from
circularity of the orbits of the planets in the Solar System is
constant; and that this total, even if concentrated on the Earth,
will not switch it to an orbit that escapes the Sun altogether, like
that of a comet. But this didn't show that the Earth might not
slowly gain energy from other planets, and drift out by bigger
and bigger almost-circles until we become lost in the silence and
the dark. Proof was still lacking that we will neither leave the
hearth nor fall into the fire, and for that the king offered his crowns.
[I do like Stewart's writing style :) ]

[So Poincare' invented topology and the idea of phase space.]
He did not settle the question of the stability of the solar system:
that had to wait until the 1960s. But he made such a dent in it
that in 1889 he was awarded his coveted Oscar, and he throughly
deserved it. .. For instance, he proved that in the motion of three
bodies there are always infinitely many distinct periodic motions...
...
In 1963, using extensive topological arguments, Kolmogorov,
Vladimir Arnol'd and Jurgen Moser were able to respond to
the question 'Is the Solar System stable?' with a resounding and
definitive answer: 'Probably'. Their method (usually called KAM
Theory) shows that most of the possible motions are built up from
a superposition of periodic ones. The planets never exactly
repeat their positions, but keep on almost doing so. However,
if you pick an initial set-up at random, there is a small but
non-zero chance of following a different type of motion, whereby
the system may lose a planet (or worse)--though not terribly
quickly. ... The fasciniating point is that there is no way to tell
by observation which of these two types of behaviour will occur.
Take any configuration that leads to almost periodic motion; then
there are configurations as close as you like where planets wander
off. Conversely, adjacent to any initial configuration from which
a planet wanders off, there are others for which the motion is
almost periodic. The two types of behaviour are mixed up
together like spaghetti and bolognese sauce.

Andrew
da***@dalkescientific.com
Jul 18 '05 #294
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:<l4********************************@4ax.com>. ..

Superfluid helium is a macroscopic phenomenon - it may be explained in
terms of QM effects, but that doesn't make it a quantum effect in
itself any more than more everyday macroscopic effects (which can also
be described in QM terms). If superfluid helium is your only clue, it
will tell you no more about quantum effects than e.g. lightening tells
you about the properties of an electron.
It is true that superfluidity is described by an effective field theory
which is not directly related to the properties of a single electron;
but still it is a (non-relativistic) *quantum* field theory, so the fact
that it is "quantum" is relevant. Things are different in ferromagnets,
for instance, where a lot of properties can be derived from classical
very unrealistic models (such as the Ising model) due to the universality
property. But not ALL properties. Anyway, I do understand that you have
in mind quantum effects related to the wave function collapse, and
I don't think superfluidity is of big help on these issues, so I must
agree with you on that point. Unfortunately :-(
It was quite a revelation to discover that the physics of the cosmos
were actually the same physics we experience on the ground.
Worth repeating.
The centre of a black hole exists, in a sense, but we can never
observe it because it is inside the event horizon, and as time itself
stops at the event horizon (from the perspective of any outside
observer) there is even good reason for claiming that the space inside
the event horizon doesn't exist.
Michele is a better one for this topic.

It is interesting to notice that the region *inside* the event horizon
is a perfectly physical region and can be relatively well understood.

For instance, an observer can fall inside the horizon and live relatively
well if the black hole is large enough and the tidal forces are small
enough; we can perfectly compute how much time s/he will live and what
s/he will see. It is true that external observers cannot see the poor guy
enter in the black hole, because of the infinite time dilatation, but
this does not mean that the guy does not enter in the black hole, according
to its proper time.

There is only one point (of a set of points if the black hole is
rotating) which we cannot understand, i.e. the singularity.
Near the singularities general relativity fails and we don't know
what happens. It is interesting to notice that Hawking proved
that GR necessarely implies singularities: this means that we know
for sure that GR is certainly not a complete
theory of Physics ;)
I read a book about string and brane theory some time ago - I guess
possibly the same one, though it has vanished into book-borrowing
space as all the best books do so I can't tell you the title.

Lots of theory about possible geometries and topologies of many
dimensional space-time and how they could change from one another.
They didn't address the issue of how they could change at all, given
that time existed within the geometry rather than outside of it, and
for that among other reasons my impression was that it was a
fascinating read that nevertheless left me with no more clue than I
had to start with.
That's normal ;)
I would at least have appreciated a definition of supersymmetry,
rather than the usual 'its too abstract for your puny mind' copout.


Supersymmetry is a much simpler concept than branes or strings:
unfortunately it is still too abstract to explain, unless one has
expertise in quantum field theory :-(

Modern physics is so difficult than you can happily spend your entire
life on a subject such as string theory and never understand it.
That's life !

Michele Simionato
Jul 18 '05 #295
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:<b1********************************@4ax.com>. ..
OK - but if you are describing superfluidity as a single macroscopic
effect then you must describe it within a macroscopic framework. At
which point it has nothing to do with quantum effects because it isn't
within a quantum framework - it is just that the macroscopic
phenomenon called electricity (distinct from electrons moving en
masse) is not subject to the macroscopic phenomenon called resistance
(distinct from energy loss through the electomagnetic interactions
between electrons and atoms en masse) when the macroscopic phenomenon
called temperature (distinct from the kinetic energy of atoms en
masse) is sufficiently low.

There is nothing wrong with this per se - it is the limit of most
peoples (mine included) understanding of superconductivity - but it
has nothing to do with the framework of quantum mechanics.


I am sure I am misreading you again, but the equation is not
microscopic=quantum, macroscopic=classical. It can be very
well quantum=macroscopic. For instance, there is no classical
theory able to describe superfluidity, it must be quantum.
If I am misreading you again, let's say that I am doing this
remark for the other readers here ;)

Michele
Jul 18 '05 #296
On 2 Nov 2003 09:11:56 -0800, mi**@pitt.edu (Michele Simionato) wrote:
Hmmm - I wonder if 'expansion' or 'scale' is a continuous value in
space-time, like curvature? Well, I guess it must be really - just
write the model in those terms and hey presto - but what I mean, I
guess, is "is there a function that can define that 'scale' in terms
of local physics to explain things we don't currently have an
explanation for?".


I do not understand what you are trying to say here.


Once, the shape of space-time (in as much as the concept existed) was
assumed separate from things that are located withing the space-time.
Now we know that space-time curvature is a function of gravity, which
is a function of the distribution of mass.

Maybe the distribution of something else determines the 'scale' or
'expansion rate' of space-time.

Which suddenly sounds familiar - of course general relativity includes
dilation of time and space related to gravity and
velocity/acceleration anyway so there is presumably no need to
postulate a 'something else' to explain the expansion of space-time
(well, besides the already postulated dark energy).

Oh well.
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #297
On 1 Nov 2003 22:19:11 -0800, mi**@pitt.edu (Michele Simionato) wrote:
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:<uh********************************@4ax.com>. .. [...]
The evidence suggests that conscious minds exist
within the universe as an arrangement of matter subject to the same
laws as any other arrangement of matter.

If there is some "stuff" whose state can eventually be shown to have 1:1 relationship
with the state of a particular individual's conscious experience, this would seem to
imply that senses and brains etc. are effectively transducers between reality and our
experiencing-stuff. Does the "experiencing-stuff" itself have matter-nature or field-nature?

From the fact that my consciousness goes out like a light almost every night, I speculate that
that what persists day to day (brains, synaptic connections, proteins, etc) is not the _essential_
basis of my experience, but rather, those persistent things somehow _shape_ the medium through
whose state-changes my conscious experience arises.

What are the limitations on the states of the experience-medium? It seems that e.g., damaged brains
create changes in the possible range of experiences, both creating new possibilities and removing
others, but this would not seem to be a limitiation of the experience-medium itself, but rather
of the reality-transducer. Besides physical brain changes, drugs can also apparently change how
the reality-transducer works or does not work (e.g., psychedelics or anaesthetics). But what of
the (hypothetical at this point) medium itself? Could it be capable of other states if it were
conditioned by another transducer? (How would the experiencer know that was happening, BTW?)
E.g., are the limitations on temperature and electrical gradients etc. of the brain effectively
limitiations on the range of possible conscious experience, that might not limit experience
conditioned through another "transducer?"

Now consider the experience of being "convinced" that a theory "is true." What does that mean?

Does our experience-medium get shaped repeatedly through layers and layers of abstraction and
re-representation to where some bit of memory is sensed to have a comfortable stability w.r.t.
sensations derived from a series of experiemnts, and we are satisfied by some pleasure-connect
with this state of brain? Is it pain and pleasure at bottom, tied to subtle internal state
sensations? Do we form theories like patterns of sand form on a vibrating membrane at quiescent
spots for a given mode of vibration? Do internal cognitive dissonances drive the "sand" away
from untenable positions in patterns of theory? Is our conscious experience-medium passive in
being shaped by the transducer, or does it have its own properties? E.g., is our sense of
connected-ness of a broken line in our visual conscious experience due to shaping of a field?
I.e., due to our very experience medium having field-nature and naturally taking some form
across gaps between features due to its own properties?
I think that mind is a an arrangement of matter, too; nevertheless,
I strongly doubt that we will ever be able to understand it. Incidentally, I think we will find out a lot yet. Beautiful, subtle stuff ;-) Too bad we are
wasting so much on ugly, dumb stuff ;-/
I am also quite skeptical about IA claims. Yes, but AI doesn't have to be all that "I" to have a huge economic and social impact.
The trend is towards private concentrated control and ownership of super-productive capital
equipment (temporarily simulated as necessary by Asian cheap labor), and AI IMO will play an
evolving role. The question is how the increasingly large fraction of people who will not be needed
for producing anything will be able to play the role of customer, unless we figure out some new
social machinery to go along with the other kind. ... Maybe a UN-member-funded humanitarian
consortium should buy Google before it becomes conscious as someone's private genie ;-)

Well, as you say,
[...]That's life, but it is more interesting this way ;)


Yes, and we could be working on global renaissance if we could globally
figure out how to spend $500bn/year (>15kUSD/second!) on good stuff
instead of miserable conflict. I would like to see leaders elected who re-affirm
at every news/media event the goal of eliminating this global stupidity,
and see the ability to kill fellow humans (at least) as aberrant instead
of just another notch on the scale of dirty-play competition that they are
willing to engage in themselves -- unable to recognize their own aberration through
the thinnest delusory veils of justification (never mind through the filters
of a raging polarized mindset).

Sorry, I get a little upset with the waste and consequent unnecessary suffering ;-/

Regards,
Bengt Richter
Jul 18 '05 #298
On 2 Nov 2003 10:16:20 -0800, mi**@pitt.edu (Michele Simionato) wrote:
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:<b1********************************@4ax.com>. ..
OK - but if you are describing superfluidity as a single macroscopic
effect then you must describe it within a macroscopic framework. At
which point it has nothing to do with quantum effects because it isn't
within a quantum framework - it is just that the macroscopic
phenomenon called electricity (distinct from electrons moving en
masse) is not subject to the macroscopic phenomenon called resistance
(distinct from energy loss through the electomagnetic interactions
between electrons and atoms en masse) when the macroscopic phenomenon
called temperature (distinct from the kinetic energy of atoms en
masse) is sufficiently low.

There is nothing wrong with this per se - it is the limit of most
peoples (mine included) understanding of superconductivity - but it
has nothing to do with the framework of quantum mechanics.


I am sure I am misreading you again, but the equation is not
microscopic=quantum, macroscopic=classical. It can be very
well quantum=macroscopic. For instance, there is no classical
theory able to describe superfluidity, it must be quantum.
If I am misreading you again, let's say that I am doing this
remark for the other readers here ;)

Michele


But within a framework you don't explain the effects described in that
framework - at best you quantify them. e.g. Newton did not give an
explanation for how gravity works - he just quantified it. If you want
to explain the classical concept of gravity, you need to look at some
other model that predicts it - e.g. gravity is created by gravitons
(an old quantum theory which IIRC has been abandoned) or gravity is
space-time curvature (a relativistic theory).

If you are describing superconductivity as a single effect (rather
than explaining it in terms of quantum effects working en masse) then
it is certainly a macroscopic effect (you can look at it), but
basically in that framework you are saying 'this is how it is, get
used to it'.

This is the same as giving a formula for electrical resistance rather
than explaining it in terms of the many interactions of electrons and
atoms within the wire. The formula belongs in the macroscopic
framework. I'm not saying a single quantum effect cannot be
macroscopic, but superconductivity is explained by the way that
electrons interact with atoms at low temperature - it is only a single
effect in itself in a macroscopic framework where you say "here is how
it is, get used to it".

If you are explaining how superconductivity arises, then it arises out
of microscopic quantum effects acting en masse.

However, now that I think harder, I just countered myself in a way.
There isn't just one QM framework exactly - there are layers within
that too (e.g. quarks relative to protons) so a macroscopic quantum
effect can be explained in terms of a microscopic quantum effect and
so on. It really depends on whether you call superconductivity a
quantum effect even though you aren't looking at simple interactions
between quanta.

Maybe my definition of 'quantum' is odd, in other words, taking a
principle too strictly and ignoring normal conventions.
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #299
On 3 Nov 2003 00:13:58 GMT, bo**@oz.net (Bengt Richter) wrote:
On 1 Nov 2003 22:19:11 -0800, mi**@pitt.edu (Michele Simionato) wrote:
Stephen Horne <st***@ninereeds.fsnet.co.uk> wrote in message news:<uh********************************@4ax.com>. ..[...]
The evidence suggests that conscious minds exist
within the universe as an arrangement of matter subject to the same
laws as any other arrangement of matter.
If there is some "stuff" whose state can eventually be shown to have 1:1 relationship
with the state of a particular individual's conscious experience
No-one has ever shown that. Actually, exactly the opposite. Our
consciousness is a very poor substitute for reality. You may see you
conscious awareness as detailed, but that is only because as soon as
you shift you focus on some detail it naturally enters the
consciousness (indeed it often gets backdated, so that you think it
was in your consciousness at a time that it simply wasn't there at
all).

What would be a particularly valued aspect of consciousness? How about
'agency' - the sense of owning and controlling our own actions - the
sense of free will?

Well, if electrodes are placed on your brain in the right place, they
can directly move your arm. So what? Well, you will be completely
unaware of the remote control - unless you are told about it, you will
claim that you chose to move your arm of your own free will. You will
even have an excuse for why you moved your arm which you believe
implicitly.

In fact you don't even need electrodes on the brain - the same effect
can be seen with people whose left and right brains are separated
(corpus callosum cut). Hold up a card saying 'get a drink' so that it
is visible only to one eye and they will go to get a drink. Hold up a
card saying 'why did you get a drink?' to the other eye and they will
show no awareness of the first card, insisting they just felt thirsty
or whatever.

Quite simply, consciousness is nothing special. It is a product of
information processing in the brain. Sometimes that information
processing goes wrong for some reason or another, and consciousness
gets distorted as a result.

The 'transducers' are our senses, providing information about reality
(imperfectly) to our brains.
From the fact that my consciousness goes out like a light almost every night, I speculate that
that what persists day to day (brains, synaptic connections, proteins, etc) is not the _essential_
basis of my experience, but rather, those persistent things somehow _shape_ the medium through
whose state-changes my conscious experience arises.
What if the thing that woke up the next day was a perfect copy of you,
complete with the same memories, rather like Arnie in the Sixth Day?

No - not a clone. A clone is at best an identical twin with a
different age as well as different memories, and identical twins do
not have identical brains even at birth - there isn't enough
information in our DNA to give an exact blueprint for the initial
connections between the neurons in our brains.

But assume a perfect copy of a person, complete with memories, could
be made. How would it know that it wasn't the same self that it
remembered from yesterday?

Now consider this...

The brain really does change during sleep. In a way, you literally are
not the same person when you wake up as when you went to sleep.

More worryingly, the continuity of consciousness even when awake is
itself an illusion. Think of the fridge light that turns off when the
fridge is shut - if you didn't know about fridge lights, and could
only see it when the door is open, you would assume the light was
always on. Similarly, whenever you try to observe your state of
consciousness it is inherently on so it apears to be always on and
continuous, but science strongly suggests that this appearance is
simply wrong.

So do we have any more claim to our conscious sense of self than this
hypothetical copy would have?

The fact is that no-one has shown me anything to make me believe that
we have 'experience' separate from the information processing capacity
of the brain. So far as I can see, the copy would have as much claim
to the conscious sense of self, 'continuing on' from prior memory, as
the original.
Now consider the experience of being "convinced" that a theory "is true." What does that mean?
Science suggests that all subjective meaning is linked to either
direct senses or action potentials in the brain. If you think of the
concept 'democracy', for instance, you may actually generate the
action potentials for raising your hand to vote (depending on your
particular subjective understanding of that abstract term) - though
those potentials get instantly suppressed.

In fact a key language area (Brocas area IIRC) is also strongly linked
to gesture - hence sign language, I suppose.

This makes good sense. Evolution always works by modifying and
extending what it already has. The mental 'vocabulary' has always been
in terms of the bodily inputs and outputs, so as the capacity for more
abstract thought evolved it would of course build upon the existing
body-based 'vocabulary' foundations.

I can easily suggest possible associations for the term 'convinced' by
referring to a thesaurus - 'unshakeable', for instance, is a clear
body/motion related metaphor.

Or maybe it relates to the body language action potentials associated
with the appearance of being convinced?

At which point I'm suddenly having an a-ha moment - maybe the verbal
and nonverbal communication deficits in Asperger syndrome and autism
are strongly linked. Maybe a person who is unable to associate an idea
to its body language, for instance, loses a lot of the intuitive sense
of that idea. Thus the idea must be learned verbally and the verbal
definition inherently gets taken too literally.

Basically, if a person has to give the concept a new, abstract,
internal symbol instead of using the normal body-language associated
internal symbol, then any innate intuitions relating to that concept
will be lost. The neurological implementation of the intuitions may
exist but never get invoked - and therefore it will tend to atrophy,
even if its normal development doesn't depend on somatosensory
feedback in the first place.

That could explain some odd 'coincidences'.

Hmmmm.

I think I might post this idea somewhere where it is actually on topic
;-)
Is it pain and pleasure at bottom
Nope - the innate circuitry of our brain brings a lot more than that.
'Pain' and 'pleasure' are actually quite high level concepts, things
which we experience as 'good' or 'bad' only because we have the
information processing machinery that makes those associations.
I think we will find out a lot yet. Beautiful, subtle stuff ;-) Too bad we are
wasting so much on ugly, dumb stuff ;-/


'Ugly' and 'dumb' are themselves only subjective perceptions. If you
really want to know the truth, you must accept that it will not always
be what you want to hear.
I am also quite skeptical about IA claims.

Yes, but AI doesn't have to be all that "I" to have a huge economic and social impact.


I thought IA != AI, though I have to admit I'm not sure what IA stands
for. Instrumentalist something-or-other?

As for AI, I'd say I agree. Having a human-style consciousness is not
necessarily a practical asset for an intelligent machine.
--
Steve Horne

steve at ninereeds dot fsnet dot co dot uk
Jul 18 '05 #300

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