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From: Taner Edis <[e-mail]>
Subject:      Re: Necessity of interpreting QM
Message-ID: <[e-mail]>
Date:         Sat, 10 Oct 1992 16:13:03 EDT

>         The sorts of 'alternative' interpretations of QM that Taner is
> talking about are often called 'philosophical', but I think this is a
> bit unfair to philosophers. In a sense they are philosophical, but
> very few philosophers put forward the sort of interpretations that
> Taner talks about (at least in Australia they don't; perhaps it's
> different in California if you're studying Applied Narcotics at the
> University of Please Yourself).  It's mostly rogue physicists, science
> journalists and paranormalists who do so.

        I was explicitly discussing what "respectable" philosophy
departments regularly deal with.  Johns Hopkins, where I'm at, has a
philosophy department that regularly offers a course on
interpretations of QM -- not the loony "paraphysics" stuff (actually,
I'd prefer that they'd do something useful and examine the lunatic
fringe, rather than indulge in exploring questions with *absolutely
no* physical consequence -- a fact conceded by the interpreters
themselves).

>         I don't agree that interpretations are irrelevant. Irrelevant
> to the physics, maybe, but not irrelevant. (Actually, I suspect that
> these extra interpretation, especially the consciousness theory, may
> have some experimental implications and could be proved wrong). If you
> just wish to do the physics, fine. But there still remains the
> question of what does all of this mean? And every physicist, when
> pressed, has an opinion on this.

        If there is to be any relevance to physically inconsequential
verbiage, it will have to be in a quasi-mythological sense.  I will
agree that most people exhibit a need for such impositions of
"meaning," but this should not obscure the fact that these are
completely arbitrary and unconstrained by any possible empirical
information.  My opinion, when pressed, is that I resent being
bothered by garbage.  I'm better off if the comment space in my QM
software is not cluttered by nonsensical metaphysics.
        The "consciousness" theory, by the way, is also lacking in any
experimental consequence -- provided that what is meant is not some
paraphysics (which I actually have more respect for, they're merely
unsupported, not irrelevant).  If some of the Wheeler-inspired stuff
is taken up, it's quickly noted that (i) they propose absolutely no
difference in any formal computation, and (ii) they might come up with
a vacuous statement analogous to "of course no experiment can make a
distinction, you need consciousness to be able to perform an
experiment in the first place!"

>         I suspect that many physicists would give a straightforward
> realist answer: we're simply dealing with the stuff that's out there
> in the physical world.

        Correct, and I might say much the same if I wanted to get rid
of the pesky questioner.  However, if inquiry is pursued further, and
what is meant by "the real world" is delved into, it will be
discovered that a coherent answer is hard to come by.
        Many physicists, and others who for cultural reasons are
deluded into holding philosophy in high esteem, think of "Realism" or
it's-all-in-the-mind type "Idealism" and various cousins as points of
view with real, distinguishable consequences.  Superficially, it seems
like Realism would hold that it would not be possible to affect the
"external world" by pure thought, since propositions are to take truth
values independently.  But would it be possible to refute Realism by
any possible success in demonstrating psychokinesis, for example?  No,
not any more than reaching out with ones hand by conscious decision
invalidates any Realist precept.  Similarly, the Idealist may seem
closer to a point of view where "you create your own reality," but the
fact that no one has been able to vanish an onrushing train by wishing
it gone need not faze such a character -- there is, after all, no
postulation of any availability of control.
        If all this Realism etc. was innocent nonsense, I wouldn't
begrudge the philosophers their fun, though I'd be curious as to how
they'd justify their salaries.  Furthermore, even if factually
irrelevant, such metaphysical language may be functional in the manner
any other mythological discourse is; far be it from me to argue that
ethical arguments should be ignored, for example.  But I have a
suspicion that pure speculation is often harmful, and for the reason
of the superficial similarities of the kind described in the previous
paragraph.  Metaphysics is not just innocent verbosity, but because of
features of the language, it induces a false proximity between certain
*factually relevant* theories.  Thus the nonsensical dispute about
what QM has to say about Realism (absolutely nothing) also fuels an
impression that there must be something to paraphysical theories that
exhibit a superficial similarity to some non-Realist points of view.
Realizing that nonfactual language can be of functional importance
(thus not irrelevant in a general sense) should not prevent us from
recognizing that its effects can also be pernicious.  In the case of
QM "interpretations," I would argue that this is not merely a waste of
intellectual resources, but a way of actively encouraging the
paraphysicists.  It is no coincidence that "interpretations" figure
prominently in arguments favoring Quantum Mysticism.

> Many physicists, however, say that QM couldn't possibly be true of the
> physical world, because of the contradictions in it if interpreted
> realistically, and so they take an instrumentalist position: QM is a
> tool for prediction they say, not literally true at all.
> [... about Many-Worlds] the sort of paradoxes that confront QM.

        This is exactly the sort of nonsense that bothers me --
arguing against a perfectly fine *mathematically consistent* theory
because some fool philosophical point looks weird to the eye of a
certain beholder.  This dispute is about as fruitful as 4th century
controversies about the nature of the Trinity.
        Let me unequivocally declare that the "paradoxes" of QM are
about as problematic as Zeno's paradox of motion, i.e. possibly
intriguing, but not leading to any inconsistencies or even any
substantive questions to be resolved.  This includes EPR, variations
on double-slit gedanken experiments, the works.

> and you'll find that virtually all the big names who were responsible
> for QM had such philosophical views, and many of them wrote on the
> subject.

        I can assure you that this is no news to me, considering that
I've been complaining about these indulgences in philosophizing for
years now; more often than not, they are but mystifying barriers to
learn about a physical framework that is plenty difficult to start out
with.  Perhaps a manifestation of a desire for beautiful theorizing
that for once doesn't have to be put to risk by some lowly
experimentalist.  Though a theorist, I am thoroughly disgusted by some
features of the internal culture of theoretical physics.  No wonder
we're accused of being a priesthood, in that in some aspects the
charge is entirely correct.

> extreme instrumentalist like W.T. Stace, who held that all
> interpretations of the mathematics in physics are meaningless. [...]
> The maths has meaning, but only as maths, not as anything else.

        My objection runs deeper -- I would go so far as to say that
philosophers still don't know what they're talking about when they use
the word "meaning" itself.  Stace's problem seems to be related to
those of some of the earlier positivists, trying to construct an
account of "meaning" based solely on properties of statements that are
to be evaluated for such, and ignoring the all-important issue of
communication.

>         The maths, nevertheless, happens to be a good tool for
> prediction.  How come? Well, when you answer this question you're
> committed to an interpretation of the maths.

        Incorrect, barring some verbal sleight of definition that
removes the distinction between interpretation and non-interpretation
(like declaring the unbeliever to have religion too, just that of
unbelief).  Inference, in general, is a way to obtain "subjective"
probabilities, that can also be applied to prediction.  If it works,
that itself is a factual question, and to be addressed in an
inferential fashion, not by some philosophical handwaving about
correspondence to some mystical Reality.
        To make this clearer, it should be noted that the
interpretations that pure speculative philosophy provides are, without
exception, pseudoexplanations that have psychological value at most.
They are in the same class as explaining rain by "a rain god that is
totally transcendent to our experience wanted it so."  This holds as
true for self-declared Realists as much as for those that love to
blather endlessly about the Absolute, or Being, or anything.

        To sum up: "interpretations" are *physically* completely
irrelevant.  And even in general, I'll assert that they are a
distraction at best, and an inadvertent support for paranormalist
distortion more often.

        Taner Edis




From: Jim Kutz <[e-mail]>
Subject:      Can quantum terms be flakeproofed?
Message-ID: <[e-mail]>
Date:         Sun, 11 Oct 1992 10:59:26 -0400

One  reads all  kinds of  horse manure  these days  from magazine
writers  about how  a quantum  event doesn't  really exist  until
observed by  a *conscious* entity.  They invariably cite  quantum
physics as an 'authority' on this. Then they go off on some flaky
'mind over  matter' tangent about  how supposedly one  can choose
which  reality  to  recognize,or  even  just  shut  your eyes and
'refuse  delivery'  on  whichever  aspects  of  reality you don't
happen  to like,  supposedly forcing  reality to  conform to your
expectations.

Yet  none  of  the  quantum  physics  experiments I've read about
require a *sentient* observer.  Apparently the observation can be
'captured' equally well by any sort of recording instrument, such
as a photographic plate or event counter.

I'm  thinking  in  particular  about  the  classic  particle-wave
experiment where a beam of photons  is split into two beams using
a half-silvered mirror, and the two  beams are then recombined on
a screen  to create  an interference  pattern, thus demonstrating
the 'wavelike'  nature  of photons (or other kinds of particles).
The  interference pattern  disappears whenever  observers try  to
determine which of  the two paths a given  photon took. The catch
is that  the interference pattern *also*  disappears whenever the
observers set up instruments which *could* make that observation,
even when nobody  is actually at the eyepiece  observing. As soon
as the  'split' photons are  rendered distinguishable by  the way
the apparatus is set up, the wave function 'collapses'.

Secondly, I've  yet to read  about *any* experiment  in which the
mindset  of  the  researchers  had  any  effect whatsoever on the
outcome of the experiment. In  every case the researchers had the
option  to observe  or not  to observe,  but they  still couldn't
make a  random quantum event come  out a certain way  by means of
'filtered' observation. Nor were observers able to 'sneak a peek'
and then alter the outcome by observing or not observing. The act
of  'sneaking a  peek' always  randomnized the  outcome. Even the
*intent* to  observe has no  effect on quantum  events, which are
affected only by the *possibility* of an observation - regardless
of whether or not an observation actually occurred.

I'm trying  to keep this general,  but I'm thinking again  of the
'split beam'  of photons forming an  interference pattern. If the
two beams go through twin maser cavities, that doesn't change the
interference pattern. OK. But if the maser cavities are gimmicked
with some kind of sensor beams (or anything else that could carry
away   information  about   which  path   a  photon   took),  the
interference pattern disappears.

What  bothers me  about this  is that  the same  phenomenon would
probably happen in nature if a  stream of photons were were split
up  and  recombined  by  some  natural  occurrence  (  such  as a
naturally   occurring  geometry,   analogous  to   a  double-slit
experiment,  with some  oddity capable  of rendering  the photons
distinguishable ).

Obviously,  when a  photon is  traveling along,  minding its own
business, and it encounters  some shiny transparent surface where
it has a choice of paths, the photon doesn't get paranoid and say
to itself:

    "Hmmm,  now  is  this  geometry  a  'setup'  by  some  sneaky
    physicist  trying to  *observe*? Or  is this  a natural event
    whose  outcome  will  never  be  observed  by  anyone looking
    closely enough to catch a photon in the act of being *both* a
    wave and a particle at the same instant. Hmm, I'd better stay
    away from that patch of  lichens, because they *could* record
    an interference pattern which  just *might* become fossilized
    and be dug up 50,000 when  those apes over there descend from
    the trees and  evolve into physicists. A photon  can never be
    too careful."

I favor  the  notion  that  the  photon  could  care less whether
primitive humans  are doing a fertility  dance or performing some
other ritual called 'observation'.

Of course the 'orthodox' quantum mechanical answer to that puzzle
is that the  photon doesn't *have* to make  a decision until it's
'observed'.  The  'official'  quantum  mechanical example usually
given   to   make   quantum   events   more  'understandable'  is
Schroedinger's  'half-alive'  cat.  If   quantum  states  can  be
indeterminate, then  why not a  cat? In this  thought experiment,
the cat is placed in a box with an automated machine. The machine
detects a quantum event which  has two equally probable outcomes.
If the  event comes out  one way, the  machine releases a  lethal
substance and kills  the cat. If the quantum  event comes out the
other way, the machine does nothing. Supposedly the quantum event
remains  indeterminate (and  so does  the condition  of the  cat)
until   the  box   is  opened,   'collapsing'  the  indeterminate
probability waves into  a dead cat or a live  cat. (Of course the
wave  function  collapses  early  if  Schroedinger  hears the cat
scratching  around  in  the  box  before  it's  opened.  Even  if
Schroedinger  doesn't hear  the vibration,  the mere  fact of the
smallest interaction  with the outside  world would be  enough to
collapse the wave function.

Well  then what  determines when  the outcome  of a quantum event
*could*  be  observed,  for   purposes  of  collapsing  the  wave
function?  That's  already  been  answered,  by  experiments that
attempt  to 'sneak  up' on  a  split  beam of  photons. The  wave
behavior collapses whenever the two  halves of the split beam are
coupled (  in any fashion  ) to any  chain of events  which would
have a different outcome depending on which path the photon took.

So why not just *say* that, and leave the 'observer' out of it?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Note that the term "coupled  in any fashion" would include 'idler
beams'  and other  sneaky  methods  of siphoning  off information
about the split beams of photons.

Admittedly,  these effects  hinder  any  attempt to  observe. But
what's actually changing the outcome  is not the observer per se,
but  rather  the  set  of   interactions  which  the  split  beam
encounters.

Admittedly there's something *very* strange going on when a split
beam of  photons is further  divided into two  'signal beams' and
two 'idler beams' by 'frequency divider' crystals. What's strange
is  that messing  with the  'idler' beams  can affect the 'signal
beams  and mess  up their  interference pattern,  even though the
two sets of beams had already parted company.

OK,  so  that's  weird.  But  it's  not  necessarily  a  'quantum
conspiracy' aimed at frustrating observers  per se. Maybe it just
*happens* that observers are the  ones getting frustrated by that
particular quirk of nature -  and attempting to state natural law
relative to their own viewpoint as observers.

The supposition  that "a wave  function collapses only  when it's
observed" is not subject to experimental test. That's like saying
"If  a tree  falls in  the forest  and there's  no-one around  to
record the event, does it make  a noise?" Well if "there's no-one
around  to  record  it",  then  it  can  never  be observed under
scientific conditions, and hence can  never be a scientific fact.
Ditto for  quantum wave functions  that supposedly only  collapse
when 'observed'. Most probably those waves would collapse anyway,
if they encountered a similar  situation *not* placed there by an
'observer'.

I think  this point  needs to  be cleared  up, because flakes are
having a field day with  the mistaken notion that quantum reality
'deliberately'  acts  in  such  a  way  as  to foil the objective
observer. This  of course then becomes  the flake explanation for
why paranormal  events never happen  around scientists -  because
reality supposedly becomes 'evasive'  when looked at too closely.
Therefore  a  lot  of  flakes  believe  that  the  key  to making
paranormal events happen is to *not*  try and pin them down. This
in turn invites charlatans to take advantage of flakes, raking in
enough money to file harassment suits in defense of irrationality.

Therefore I  think that closing  this loophole with  more precise
language  would help  restore confidence  in 'objective' reality,
and  avoid  feeding  into  galloping  irrationality.  After  all,
quantum reality *is* objective to the  extent that all of the key
phenomena are reproduceable and consistent.  A guy with a pyramid
on his  head sees exactly the  same thing as a  physicist when he
looks into an interferometer.


          - Jim Kutz ([e-mail])

--

A Fair Witness is one who, if asked:
"Is that house over there white?",
answers: "Well it's white on this side."





From: Taner Edis <[e-mail]>
Subject:      Re: Edis, physics & the 'real' world
Message-ID: <[e-mail]>
Date:         Mon, 12 Oct 1992 18:41:38 EDT

> Firstly, he seems to be taking it as read that any non-empirical
> statement is not a factual statement.

        No.  A formally factual statement can still be physically and
inferentially inconsequential -- QM interpretations being prime
examples.  I presume it is granted that the interpretations I'm
discussing, such as "Many Worlds," do not involve any possible
experimentally distinguishing characteristic.  If not, I suggest that
an examination will quickly show that this is indeed the case.

> [on "physical object realism"]
>         None of these theories need differ on any 'physical
> consequence'.  According to Taner's reasoning, they must therefore be
> all 'metaphysical wastes-of-intellectual-brain-space'. Is Taner really
> maintaining this?.

        Yes.  I also maintain that when a physicist talks about
"physical objects," he is functionally communicating something,
independent of extra interpretations that may be associated with it.

>         What grounds are there for physical object realism? One
> obvious ground is that physics talks about physical objects having
> such-and-such properties,

        Again, it would be mistaken to directly connect this use of
language to the interminable philosophical debate about "Reality."  In
any mechanics (quantum as well as classical), for example,
experimental information is translated into a probability distribution
over a "state space."  This is basically an information-preserving
transformation to a description that is convenient, and, more
importantly, is not unique.  The language of "electron at (x,p) in
phase space" can be functionally equivalent to another form of
physical description, perhaps one that is not so close to our familiar
imagery of a projectile moving through the air.  The question of which
formalism is used and why is at least partially a factual one,
answered by historical explanations (physics has no lack of archaic
formalisms that can impede understanding), and convenience.

>         What is often considered the best argument for physical object
> realism is Occam's razor, the principle of simplicity. Suppose we then
> say that physical objects are the simplest explanation of what we
> observe. Fair enough. But Occam's razor is not an empirical statement
> with 'physical consequences'. You can't go out and test Occam's razor.
> Is this also a piece of metaphysical nonsense?

        "Physical objects," in the metaphysical sense, would be hard
pressed to explain anything.  At best, it is a redundancy that can be
tacked onto any function description, like the Many Worlds
interpretation (which can, by the way, be added to classical physics
without any problem, it's just more boring in that context).
        If Occam's razor is to be taken as a methodological criterion
to be used in inference, i.e. in obtaining some sort of probability
distribution over a function space given partial information, this is
a different matter.  QM interpretations are not formal statements
about mathematical properties of inference, but formally factual (and
redundant) theory-components.
        "Simplicity" in this case is a difficult concept: in general,
it applies to *function descriptions* rather than functions
(computational complexity is a generalized cost minimum among
descriptions).  Consequently, reliance on simplicity concepts alone in
defining a proper inferential procedure invariably encounters severe
problems of arbitrariness (essentially general forms of Goodman's
paradox).  A useful simplicity concept will have to be derived from a
generally reparametrization-invariant (or description independent)
account of inference, which is not fully available as yet.

> You have no justification for believing in physical objects, any sort
> of external world, the past, the existence of other people and so on.
> Nothing but your own experience. The most extreme sort of solipsistic
> skepticism.

        In an absolutist, metaphysical sense, no, I have no such
justification.  This does not preclude me from understanding "the
past" or "other people" as elements of theoretical explanations, which
are extremely useful and successful inferentially.  A distaste for
speculation and descriptive redundancy does not imply a functional
solipsism in the least.

> Your argument here is that philosophy is harmful because some of it
> sounds enough like paraphysical theories to encourage the
> paranormally-minded.

        I'll concede that I made an overgeneral statement against
philosophy as a whole.  On the other hand, I occasionally suggest,
half-jokingly, that philosophy departments should be dismantled, and
distributed among other places, such as literary criticism and
theoretical computer science.  I have a suspicion that it is a
historical accident that keeps the "useful" philosophers (analytic and
interdisciplinary scientific crowd) together with the rest.
        However, I still see a significant speculative tradition in
philosophy that *is* instrumental in supporting pseudoscience, if
often through the "philosophical" indulgences of prominent scientists
themselves.

> Whether or not there are contradictions in QM, the fact is that it's
> presented as involving them, and you can hardly blame people for being
> suspicious about it all.

        Presumably, with a theory that has by now been around quite a
while, some people could figure out whether there are mathematical
deficiencies in it or not.  It happens not to be the case,
particularly as far as the familiar "paradoxes" are concerned, a
claim we can make without severe overstatement.

> I can't also believe that you've dismissed Zeno's paradox of motion so
> easily.

        That some interesting questions relating to Zeno's paradox can
still be raised is irrelevant to the point I was trying to make -- in
fact, right off the bat I can think of some problems relating to the
continuum hypothesis.  But in the context of classical mechanics, with
a continuum already in place, there is no mathematical problem
associated with the summation of the infinite series that arises.
*That* is the analogy.  QM interpretations do not generate a "close"
but distinguishable theories, they are functionally *identical*.

> This seems to be half the problem with many scientists: they don't
> really know what philosophy is, or how to reason outside of their
> field.

        I'll work on keeping scientists out of unconstrained
speculation, if Campbell tries to restrain those in his field that
enjoy empirically nonreferent theorizing from butting into science.

>         Taner talks here as though he's shown that interpretations of
> 'pure, speculative philosophy' are 'pseudoexplanations'. I just want
> to re-iterate my claim that he's shown no such thing, though I have a
> fair bit of sympathy with his suspicions about speculative
> metaphysics.

        I consider physically inconsequential and inferentially
redundant theory-components as being pseudoexplanations.  Speculative
philosophy has a good deal of this going on, from QM interpretations
to some quasi-theological statements.  It is difficult to say more,
especially as exploring some relevant concepts in computational theory
is difficult without resorting to extensive display of equations.
When I look back, half the words I use can be easily misinterpreted,
but I can't keep this posting within reasonable bounds without such
vagueness.  Frustrating.

> And just what does he mean by 'physically irrelevant'? That any
> possible experience or 'physical' happening is consistent with the
> assumption of their truth?

        Close enough, though considerations of "information" will have
to come up if a tighter definition is desired.  I'll just hope that
the general idea is understandable to a degree.  Otherwise, the
discussion is going to explode into book length.

        Taner Edis

"If you explain so clearly that nobody can misunderstand, somebody
will."          -- from my systems `fortune' program





From: Taner Edis <[e-mail]>
Subject:      Re: Physics & Philosophy
Message-ID: <[e-mail]>
Date:         Tue, 13 Oct 1992 11:20:33 EDT

>         I still don't agree with a lot of what Taner Edis says, and I
> think he faces problems with his extreme modern positivist-type views,
> his talk of 'functional roles' and his unclear explanations in terms
> of information,

        Part of the problem may be that I don't use the usual
philosophical language, at least not very well -- being in statistical
and condensed matter physics, my jargon and my concerns are heavily
influenced by this.  I've had occasion to study some more technical
aspects of the philosophy of science, for example, but I still have
the impression that this area of philosophy can learn much from
computer science, statistical physics and information theory (which
are pretty closely connected, nowadays).  Which is not to say that I
didn't and can't still learn from (the more analytic brand of)
philosophers.
        As for the extremism: I certainly have no claim to be
representing the mainstream of current philosophy, and I'm not exactly
bothered by being called "extreme" -- as long as it's not a device to
excuse ignoring what I try to say.

> Then think of all those undergraduates doing Arts, or Liberal Arts, or
> Humanities or whatever it's called over there. Many of them don't care
> for science or the scientific way of looking at the world. Many of
> them can't think properly. And many of them are ready to embrace
> pseudo-science and/or mysticism.

        Actually, the premeds among my students bothered me the
most...  It may be correct to say that philosophy departments can play
a constructive role in connecting the intellectual subcultures of the
technical fields and the literary/interpretive ones.  Is this being
done to any adequate extent? (not a rhetorical question, I just don't
know)
        I would also like it if my original not-fully-serious comment
about closing down the halls of philosophy was taken more in that
spirit.  I'm not about to lead a band of math-crazed physicists to
picket our philosophy department any time soon.

> I also hold that many important philosophical areas (especially
> philosophy of mind) are really a form of theoretical science of a very
> general kind, and cannot be pursued without an understanding the
> relevant empirical facts, and philosophers not prepared to aquaint
> themselves with the empirical data have no active place in the field.

        Here I agree strongly -- Dennett, for example, which was
brought up in connection with the AI debate, happens to be a person
whose work I also admire.  Work of this nature, which at its best is a
very valuable interdisciplinary synthesis, is crucial, and with the
fragmented specialization of science, perhaps it is only the
philosophers that can engage in this, for practical reasons.  I still,
however, think of Dennett as more akin to a general theoretical
scientist than a speculative philosopher (the crowd that comes up with
those awful "Chinese Room" variants of the zombie pseudoproblem and
then procede to take it seriously...).

>         One thing about media-star scientists that's really been
> pissing me off lately is the way this talk about 'God' is getting out
> of hand. It was bad enough when Paul Davies wrote 'God and the New
> Physics'. I could find little fault with Davies at this point, and his
> metaphorical use of 'God', but many people jumped on his use of 'God',
> and thought he was presenting some sort of support for religious
> views.

        Interesting -- this is also one of my pet peeves.
Unfortunately, I can get really worked up about this, so I won't get
into my complaints about this form of physics-abuse.  But I'd welcome
it if Campbell initiates a debate on this issue.  I'll even promise
not to call philosophy "worthless scum" or anything.  At least not too
often...

        Taner Edis