Dear Pat,                                               March 26, 1997

It is encouraging  that my previous letter has clarified my 
thinking for you enormously. But your tendency not to pay close 
attention to *my actual words*, but substitute your own with substantially 
different meanings, has caused you to miss some essential points. 
(<....> my highlight)

Your first question was how classical physics can tie its PAF equations
to its macroscopic #predictions#.

There is a major misunderstanding there. In elaborating on your point 
you said: 

"Of course it requires very little biological theory to make such an
observation. My point was different: that it requires rather a lot of such
theory to tie this observation to the PAF language of classical physics.

"There is a subtle point here. The 'classical conception' claims that its
equations are in principle complete, so that it <predicts> the outcome of
every physical experiment. But it can actually MAKE such a <prediction> only
if it is provided with a sufficiently detailed description of the
experimental conditions. The outcome of the experiment may in some sense be
foregone, but to actually make the connection between the PAF account and
the refined-ordinary-language observations (of color or of pointer
positions), <such a detailed description must be available>. THIS is where
the 'connecting theory' or 'meanings-for-free' play an essential role."

"<This entailment only holds if the totality of little pieces which make up
the leaf (the description of the leaf in PAF language) is somehow made
explicit>. The classical picture may assert that such a decomposition must
exist: but that is not enough to <predict>, only to express confidence that 
one  could <predict> if one knew enough of the details. Other sciences, or
'meanings', or SOMETHING, must provide these details."

You have not paid close attention to my words. When speaking of entailment
from classical physics I always specified that the entailment was from the 
<complete classical physical description> plus the Bohrian theory of 
experiment. I have repeatedly emphasized that this `complete 
classical physical description' is <the complete history of all the PAFs
from the beginning of time to the end of time>. Thus no <prediction> is 
needed for entailment from this base. You yourself explicitly admit,
above, that entailment does follow from this complete base. The point is that
the classical conception asserts that this `complete classical physical
description' does exist. The equations merely place conditions on this 
reality: they play no role in my argument. It is only the assertion
of the existence of this definite classical description that I use
or need. I am not trying here to DO or to USE science to solve a
practical problem: the issues are logical and conceptual. And the
only entailment I need in this context is from this broad base.

So in the situation involving the green leaf the premise is that there 
exists, as classical physics avers, a  complete classical physical
description of the world (a physical-world history), and that in this real
world a boy gardener engages in an activity which he describes to himself 
and others as plucking a `leaf' from a `rose bush', putting it into a certain
device, and reporting that he "sees a spot lying between `8' and `9'". 
Of course, there can be mistakes in scienfific observation, and these 
have to be weeded out by a tedious process, but if we discount the 
possibility of a mistake in this simple case we can say, given the precepts 
of classical physics, including the Bohrian account of "experiments", 
that the actual world history is in fact one in which some physical structure
that has a shape that the boy gardener `sees as leaf shaped',
(and which, in this world history, was plucked from a structure of PAFs
that appeared to the boy gardener to be `shaped like a rose bush'),
seemed to the boy to be placed by him in a device, whereupon a certain
spot of light was then seen by the boy to appear on the dial at a location
"lying between `8' and `9'".
 
In this specific situation the world history in terms of PAFs entails 
a certain fact about a  `leaf', where this `leaf' is characterized 
preciesely by what this boy recognizes and reports as a `leaf'. 
This datum may eventually become integrated into a more comprehensive 
biological theory involving cell biology. But at this stage it is a 
putative biological datum that was entailed by the complete classical 
physical description of reality plus the Bohrian account of experiment, 
which in this case specifies the meaning of `leaf' to be what the boy 
recognized as a `leaf' (by virtue of his training as a gardener), 
and reported as a `leaf'.  

*Entailment* from the complete classical physical description plus the 
Bohrian theory of experiment into the world of human experience means 
the process of injecting articulated facts into the realm of human
discourse by means of the capacities of human observers to experience 
macroscopic properties that: (1), are carried by the PAFs,
and (2), they have learned to recognize and report about.

You say:
"Of course it requires very little biological theory to make such an
observation. My point was different: that it requires rather a lot of such
theory to tie this observation to the PAF language of classical physics."

You have not explained why more biological theory is needed to account 
for this entailment, from this huge base, of the fact in question.

`Seeing a cell wall disintergating' is exactly analogous, in the case 
that I described, where the observer was a boy who was taught nothing about
"cells" and "cell walls" but how the recognize them under the microscope,
and report what he saw.

You say:
"Second, you have now made clear that you want to make a
very sharp distinction between two classes of observations, allowing only
one kind into classical physics; but I can see no reason to make this
distinction, which seems based on a very simplistic notion of 'direct'
perception."

My distinction was based upon the fact that classical physical theory
is built on the notion of forms in spacetime, and that these notions
are generalizations extracted from the character of "certain" of our
experiences, #primarily# our visual experiences, although we do also
have some experience of the spacetime location of the source of a sound,
and also the location of something we touch. But we only <see> the stars 
in the heavens, and astronomy was important in the creation of classical 
physics. Also, our idea of spacetime points probably arises mainly, 
for most of us, as a generalization of aspects of our visual experiences.

You say:
"This 'proposed 'tie-in' is unacceptable, for several reasons. First,  the
PAF description is in terms of spacetime forms, but that doesnt mean that
it specifies *all* spacetime forms."

I have repeatedly emphasized that I am not trying to encompass *all* of
everything, merely all of what can reasonably be  called classical
physical science. But the complete classical physical description does, 
according to classical physics, specify *all physically existing* 
spacetime forms. 

You continue:
" In our example, even if it completely
accounts for all the particle trajectories of the the pieces of a leaf,
that alone doesnt tell us where the leaf is until one has also identified
that part of the total plenum as *being* the leaf, and classical physics
makes no claims to be able make *that* identification."

As regards the identification of the `leaf', the central point of 
my account, repeatedly stressed, is that it is the *trained observers* 
who singles out some part of the total plenum as the `leaf' upon which
he is going to perform a certain experiment.

You then say:
"Second, as Aaron has
emphasised, most of ordinary language (even refined ordinary language used
by trained observers) does not refer simply to properties that are
expressible in terms of spacetime forms: this picture of language and how
it operates is just plain wrong. So how is the rest of observational
language to be tied to PAF?"

My repeatedly emphasized point is that I am *not* trying to encompass all
of language: I am trying to separate off classical physical science, which,  
because of the interconnectedness of language, is not an easy task.

You say:
"Let me ask you directly, as you often seem to wriggle on this point. Does
it include any part of (1) psychology, (2) linguistics or (3) medicine? Or
is all this (and any other science which sets out to empirically
investigate human thought or experience) to be regarded as 'mere opinion'?"

I do not exclude them by definition, and some parts of these disciplines
could satisfy my criteria for belonging to the classical physical sciences. 
A lot of medicine certainly does. Of course, most of human thinking is not 
about the physical sciences, and I anticipate that much of psychology will
not fulfill the criteria I have set for being part of what I define to 
be `classical physical science'.
 

You ask:
"What singles out 'matching of spacetime forms' as the crucial kind of
observation? Is this supposed to be an empirical claim about the way that
experiments are conducted? It seems entirly ad-hoc and arbitrary, since the
complete physical description predicts many other observable aspects of the
world."

The basic premise of the discussion is that the classical conception of 
the physical world is correct. But this classical conception is based on 
the conception or notion of *forms existing in spacetime*. This notion, 
or idea, is a generalization of "certain" aspects of our sense experiences.

By "certain" I mean to stress that when one `hears a sound' the experience
may have a quality of "coming from some location". But it also has a 
quality of "pitch" that can be separated off from "location":
we can experience that two sounds coming from different locations have,
nevertheless, a certain aspect that can be recognized as being the "same",
namely the "pitch", or the "timbre". The classical conception of physical
reality says that the complete classical physical description
of some physical object, like a horn, can be specified without associating
with the horn itself a quality that is like the pitch we experience,
perhaps refined. But the theory does associated with the horn something like
the location that we experience the horn to be at. This experience
of an object's  "being at some location at some time" is much more vivid
when we are "seeing it" than when we are merely hearing it. But in any case, 
this experiencing of an object's being at a certain location can be 
conceptually disjoined from the experiencing of the qualities of
pitch, timbre, and color. The classical conception of the physical world 
says that the complete classical physical description is in terms of 
locations, and quantitative properies located at spacetime points: 
the physical description of the physical object is asserted by classical
physics to be complete without including in the description properties 
like what we feel when we experience "pitch" , "timbre", or "color".
The <equations> that restrict the allowable possible forms that a 
possible physical world can have, and that renders each such possible world
dynamically complete, deals exclusively with these spacetime 
forms.

By virtue of this fact---that classical physical theory conceives the 
physical world to be built out of spacetime forms that are, by nature,
generalizations  of our experiencings of spacetime forms---we can correlate 
structures existing in  physical world to our experiences of the world 
by experiencing <matches> between the spacetime forms specified by
<the complete classical physical description of nature> and spacetime forms
occurring in our <empirical experiencings of the world>.

The thing that makes this kind of mapping special, within the context
of classical physics, is that this is THE ONLY WAY of correlating the
complete classical physical description of nature to our empirical 
experiences without introducing bridging principles that relate the 
structures that the physical world is asserted to be built out
of---namely spacetime structures---to other kinds of empirical
experiences. For example, one cannot *deduce* from the complete
classical physical description of nature which `color' will be experienced
when some observer looks at the leaf; for the complete classical physical 
description is, by assumption, built exclusively out of properties like 
the properies we experience when we experience spacetime forms,
not including properties like the properties we experience when we experience
colors. 

You say:
"Its so easy to think of counterexamples (Newtons light refraction
experiments, Fermi's first nuclear-critical event (detected by
loudspeakers), etc.) that I wonder what makes you claim it is true."

In these experiments one cannot *deduce* just from the complete
classical physical description of nature that Newton experienced
a band of red here and a band of blue there. The connection between
the frequencies of the light vibrations and the experienced colors
is not entailed by that putative complete physical description
of nature, which contains no specifications about experienced colors.
On the other hand, the fact that in this description 
of nature a `leaf-shaped' object was plucked from a `rose-bush-shaped' 
object is a fact that IS represented in this description, and this fact
can be directly experienced by the boy who is doing the plucking
because the theoretical and empirical experiences are <of the same kind>,
and he has been trained to recognized and give names to various experiences 
of this kind. He may also be trained to recognize and give a name 
"GREEN leaf" to a leaf that he sees as a leaf that is colored green.
But in that case there is no possibility of a matching of his actual
empirical experience against the facts specified by the `complete 
classical physical description of nature' because that description 
does not contain anything of the some kind as his actual experience
of greeness, although it does contain information about certain 
vibrational frequencies near the leaf.

You say:
"Im afraid I just disagree with you...When I say that a leaf is green, 
I am not referring to anything in my head, but to the COLOR OF THE LEAF.
...
but the claim made by this report (1B) is about the world, not my 
experience. That claim would be expressed by your (2B). Color is a surface 
reflectance property... That they ARE green, however, is a
fact about them, not about experience."

What is under discussion here is a  comparison between two things. 
When you say the leaf is green <you mean> something about the world. That 
is fine. But there is also something else here that is relevant to this 
discussion about the connection between physical and phenomenal facts. There
is a fact about experience that you say is represented by a different
sentence, 2B. If by `something about the world' you mean something about the
world as that world is conceived to be represented in classical mechanics
than that property of the world would be about the frequency of some 
vibrations.  The corresponding phenomenal fact, the actual `experience
of greenness' experienced by the boy gardener, and referred to by sentence 2B, 
does not have within it a specification of vibration frequency:
in the case of greenness the phenomenal and physical facts do not have 
the quality of sameness-in-kind that the phenomenal and phyical facts about
spacetime form can have: one cannot experience the same sort of felt 
congruence that one can experience between one's empirical experience of 
a certain spacetime form and one's theoretical picture of a spacetime 
form specified by the complete classical physical description of nature.

You say some things about failure of observations to be veridical, under
certain conditions. But that is not the point here: let us focus on simple
ideal cases where the problems of illusions and delusions and mistakes
have somehow been weeded out. These are the most pertinent cases.
But precisely in these cases there is a big DIFFERENCE IN PRINCIPLE between
spacetime forms and a quality such as greenness: the *nature of the 
connections* between corresponding physical and phenomenal facts
is completely different. And the origin of this PRINCIPLED DIFFERENCE
is a matter of principle, within the context of an assumed-to-be-correct
classical physics: that physical theory builds its picture of the physical
world precisely on structures in spacetime, and it exclude from this
image of the physical world properties that can be identiable as the same 
properties (perhaps idealized) that we immediately experience when we 
experience the greenness of a leaf. Phenomenally experienced greenness 
and phenomenally experienced spacetime form are DIFFERENT IN PRINCIPLE
in the context of their connections to the concepts used by classical
physicists to build their theoretical model of the physical world.

You say:
"In any case, if I read you properly here, your 'principled' difference
simply amounts to the fact that science has singled out one kind of
observation as being more, well, *scientific*, than other kinds. Even if
your account were correct, this difference would be a matter for historians
to ponder, not a 'principled distinction'."

Yes and No! I certainly agree that historians will be amazed 
that scientists tried for so long to cling to an already-proved-false 
conception of nature that was so obviously ill-suited  when they
had at hand one that was so well suited to the problem. It is that
`science' has singled out this ill-suited philosophy. Science has moved past
that primitive and false conception to one beautifully suited one to the
problem.  The `principled difference' exists only in the context of the 
outmoded and manifestly incorrect classical philosophy, which gives no
adequate status to almost all of our experience.

You say:
"All this is wrong. We don't 'directly perceive' anything about the world,"

Your words do not match or mean the same as the words of mine that you
are reacting to. I did not say "We directly perceive". That terminology
raises the ghost-on-the-machine spectre. 
I said:" although in both cases the empirical experience is
>(presumeably) an aspect of brain activity," 

You continue:
"and our experiences are not 'likenesses' of the world. (Think: what would
the point be of maintaining an internal likeness of what you see? All you
could do with it would be to look at it, and you are doing that already.)"

I am not suggesting that there is some "me" who is looking at my experience.
"The experienced "I" is an aspect of a certain cohesive realm of experience."
 Nor am I suggesting that our experiences of the world are `likenesses'
of the world: just the opposite! Certain aspects of our experiences 
of the world---namely those pertaining to spacetime form---are `like'
(not the actual physical world itself, but rather) aspects of the (clearly 
false) classical image of the world, precisely because classical physics
created this (basically false) classical image of the physical world out of 
certain generalizations of those particular (i.e., spacetime) aspects 
of `our experiences of the world', and essentially ignored all 
other kinds of experiences.

You say:
"You may fail to appreciate how much internal work is needed 
....with our sense of the stable physical world. Our
spatiotemporal experience is not nearly as 'directly' attached to nature as
we feel it to be. (Many aspects of the design of instruments (mirrors
behind pointers, vernier gauges) are devoted to overcoming these errors.)
Our experience of position and shape is no more 'transparent' in its access
to the world than our experience of color (or indeed of touch, scent or
taste.)"

True! So is it not foolish to tie our physical science to a conception of the 
physical world so biasedly based on this one aspect of our experience of the
world, as if it is somehow sacred?

You say:
"If this really is the classical conception (which I doubt), then I agree
that the classical conception is wrong. However, there is no need to turn
to quantum mechanics, only to have a slightly more sophisticated notion of
what constitutes an observation (one that is more in accord with the
realities of science, and which I suspect Bohr might have endorsed.)"

I do not think one can rationally deny the fact that the classical 
physics conception of physical reality is based on structures in space 
and time, and that this structure does not include among its  properties
any property that is identifiable with the *phenomenal* experience of, 
say, greenness. So the issue is not what counts as an observation
(certainly experiencing green and experiencing location are similar
in terms of phenomena, but the classical conception of nature does not treat
these phenomena symmetrically), but which kinds of observations can be
be regarded as experiencings of features of nature that, according to the
*assumed* physical theory, are features of the physical reality.

You say:
"On the matter of 'seeing though' our experience to the outside, there is an
important point (which goes well beyond our little quarrel!). Even if one
concedes this distinction as being important, notice that it obviously must
be modified if the 'forms' predicted by physics are in fact INSIDE the
observer's own head, which is the case for subjective experience-reports.
In this case the 'outside world' has become part of the observing system
itself. This is not to endorse the idea that we can "see" into our own
heads, of course; but it is the case that physical events there produce
experiences which we can describe to others, just as external positions and
forms reflect light which, hitting our eyes, produces experiences of the
world which allow us to make reports. The cases seem quite parallel to me,
and I see no reason to suppose (and every reason to deny) that the complete
physical story determines my experiences in one case but not the other."

Yes indeed! This is THE problem with the classical conception! The lopsided
treatment that essentially ignores most experience.

You say:(first quoting me)
">Although science can evolve in many ways, it remains physical, at least in my
>definition, only insofar as the interface between theory and experiment
>remains
>Bohrian, with the `physical' in `technical physical interpretation'
>meaning that the PRINCIPLED DISTINCTION between physical
>and phenomenal described above be retained

If you make this a matter of DEFINITION, as you here seem to, then this
entire discussion is a complete waste of time, all your claims are vacuous
tautologies, and none of your substantive conclusions have any content. I
hope you don't really mean to make this claim."

I want to separate from all of human knowledge a particular small part 
that I would like to call `classical physical science'. It should, at
least in principle, be about
those aspects of nature that can be conceived to be built up out of
the PAFs of the complete classical physical description of nature, and
to have no properties that are not at least in principle entailed by 
this complete classical physical description of nature taken together with
the linkage into human experience provided by the precept that--- because
the conceptualization of the physical world provided by classical
physics is erected on our notions of spacetime form extracted from certain
sense experiences---we can empirically experience spacetime forms that
can be taken to be identifiable with spacetime aspects of the 
complete classical physical description: moreover these spacetime forms 
can, because of this identification and the precepts of the theory, be 
considered to belong to both the physical and phenomenal worlds. They
can be linked into our other thoughts and theories, and in fact
become associated with words and other symbols, so that something like a 
`leaf' can come to be defined through interactions of the community
of communicating observers with the classically described world of which 
the observers and a plenum of spacetime forms are parts. Certain facts
about the plenum of spacetime forms that constitute the physical world,
in this classical conception, can by means of this interplay,  be become 
known, articulated facts in the minds of the community of communicating 
observers.

Classical physical science builds itself, according to this definition,
always by this interplay between the world of physical and 
phenomenal facts through the mediation of these facts that can
be conceived to belong to both. People  can spin theories about
aspects of the physical world that can be conceived to be defined in terms of
the properties of the PAFs, and can test those theories by comparing how the
spacetime forms entailed by the complete classical physical description
matches against the spacetime forms empirically experienced. The 
linkage down to the level of PAFs needn't be explained in detail, but
the higher-level properties should at least in principle be entailed
by the PAF-level description. 

The bottom line is that because the classical model world is built 
exclusively upon idealizations and generalization of our sense experiences 
about spacetime structures it is only these special kinds of empirical 
experiences that can be conceived to be experiencings of the putative 
physical world itself. That constitutes a PRINCIPLED DIFFERENCE  between 
these kinds of experiences and, for example, a phenomenal experience 
of greenness. This difference biases  the whole picture in the way
I have outlined above, and it prevents these latter sorts of empirical
experiences from being entailed by the classical physical model in the 
way that empirical experiences of spacetime forms can.

I hope this message will finally succeed.

Best regards,

Henry         <hpstapp@lbl.gov>