BIG successes of Lisp (was ...)

[mike420]

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.

[Stephen Horne]

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 deterministical ly
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

[Michele Simionato]

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 "theoretica l 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 interdisciplina ry 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 ;)

[John J. Lee]

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

[Michele Simionato]

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

[Michele Simionato]

Robin Becker <ro***@jessikat .fsnet.co.uk> wrote in message news:<t8******* *******@jessika t.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

[Michele Simionato]

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

[Anton Vredegoor]

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

[Michele Simionato]

Stephen Horne <st***@ninereed s.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

[Stephen Horne]

On Tue, 28 Oct 2003 15:49:04 +0100, an***@vredegoor .doge.nl (Anton
Vredegoor) wrote:

mi**@pitt.ed u (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
correspondin g 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 (indistinguisha ble 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

[Stephen Horne]

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