[From Dag Forssell (960706 23:55)]
Introducing Bruce Gregory.
I first became aware of Bruce when I received an order for my
book and the Rubber Band video in February. I called to follow
up, and Bruce ordered everything else I have as well. Bruce
mentioned his book and warned that it has recently gone out of
print. I failed to locate a copy, so Bruce gave me one. I think
it was his last spare.
Bruce has set a new record for understanding, acceptance and
support of PCT as far as I can tell. Now that I have read Bruce's
book, I think I can see why. Bruce comes to PCT with a meta-
science point of view, and is more than ready to appreciate that
a new approach may be incompatible with the old.
I find it useful change my approach to promoting PCT in light of
Bruce's discussion. Some of us feel that behaviorism is WRONG and
PCT right. I now recognize that these are merely different
languages. Behaviorism as a language is purely descriptive and
largely useless, but it is one language. PCT is, in my opinion, a
language that is more effective and useful -- by several orders
of magnitude -- but it is still just another language.
I have scanned enough of the book to convey Bruce's idea. Below,
you will find the Table of Contents, Preface, each Chapter
Heading with Quotation, Chapters 14 and 15 in their entirety and
finally the Epilogue.
I have had to retype most of the quotations, and have run spell
check on all of it, but have not read the scan against the text,
which has rather small print. It is possible that some word or
quotation mark came out wrong or is missing (if it is short).
Sorry, but I have not taken the time to indicate all the italics.
I hope PCTers will find this thought provoking.
Following this lengthy excerpt, I will enclose a few personal
notes from Bruce.
···
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INVENTING REALITY
PHYSICS AS LANGUAGE
BRUCE GREGORY
[from the back cover]
Physicists do not discover the physical world. Rather, they
invent a physical world ' a story that closely fits the facts
they create In experimental apparatus. From the time of Aristotle
to the present, Inventing Reality explores science's attempts to
understand the world by inventing new vocabularies and new ways
to describe nature.
Drawing on the work of such modern physicists as Bohr,
Einstein, and Feynman, Inventing Reality explores the
relationship between language and the world. Using ingenious
metaphors, concrete examples from everyday life, and engaging,
nontechnical language, Gegory colorfully illustrates how the
language of physics works, and demonstrates the notion that, in
the words of Einstein, "physical concepts are free creations of
the human mind."
BRUCE GREGORY is Associate Director of the
Harvard-Smithsonian Center for Astrophysics. For over twenty
years he has made science intelligible to audiences ranging from
junior high school students to Members of Congress.
JOHN WILEY & SONS ISBN 0-471-52452-4
Professional and Trade Division
CONTENTS
Preface v
Prologue 1
1 In the Beginning Was the Word 5
2 The Invaluable Concept of Force 19
3 The Indispensable Idea of Fields 35
4 The Ingenious Notion of Atoms 49
5 The Unimaginable Unity of Spacetime 59
6 The Imponderable Nature of Matter 71
7 The Intransigent Presence of Paradox 89
8 The Inexhaustible Fecundity of Space 101
9 The Improbable Prevalence of Symmetry 119
10 W. Z Fields 135
11 The Ineffable Color of Quarks 143
12 The Unquestionable Imagination of Physicists 157
13 The Inscrutable Essence of Mathematics 169
14 The Unspeakable Power of Language 179
15 The Last Word 193
Epilogue 201
Appendix A: Is There a Fact in the Matter? 203
Appendix B: Schroedinger's Cat, the Problem of
Measurement, and Language Domains 209
Notes 213
Bibliography 221
Index 225
PREFACE
Physics has been so immensely successful that it is difficult
to avoid the conviction that what physicists have done over the
past 300 years is to slowly draw back the veil that stands
between us and the world as it really is ' that physics, and
every science, is the discovery of a ready-made world. As
powerful as this metaphor is, it is useful to keep in mind that
it _is_ a metaphor, and that there are other ways of looking at
physics and at science in general. Ways that may prove even more
illuminating than the 'obvious" view.
This book tells the story of how physicists invented a
language in order to talk about the world. In this sense, the
book is not 'about' physics. Although I hope the reader will
discover something about Physics, my purpose is not to try to
explain the discipline, but to explore the relationship between
language and the world. Physicists use a very precise language,
and this precision gives us an opportunity to see more clearly
than is otherwise possible just how much of what we find in the
world is the result of the way we talk about the world.
The physics discussed in this book is sometimes called
fundamental physics, but this understandably offends physicists
who feel what they are doing is every bit as fundamental. Much of
fundamental physics is also called high energy physics or
particle physics. Other branches of physics have had a much
greater effect on our lives. For example, solid-state physics has
had an immense impact as a result of the development of
transistors and integrated circuits. The physics whose history I
trace is concerned with understanding the ultimate constituents
of matter and the nature of the forces through which these
constituents interact. It attempts to answer the question, What
is the world made of, and how does it work? These are clearly
fundamental questions, if not the only fundamental questions. I
chose to focus on this branch because I think it has something
particularly valuable to tell us about the general quest to
understand the 'furniture of the universe' ' the stuff we think
of as real ' and the role that language plays in creating and
supporting this conviction.
I use the word language throughout the book, and it is
helpful to know what I mean by it. I call any symbolic system for
dealing with the world a language. The language of physics is
mathematics, and I refer to particular domains of mathematics as
the language of classical physics or the language of quantum
mechanics. I also refer to the vocabulary of Newtonian physics,
where I mean the Newtonian approach to dealing with physical
situations in terms of forces and changing position with time. I
take this approach to make it clear that physics Is a language, a
way of talking about the world. As to what else we can say about
physics, this is something the book sets out to explore.
The story I tell resembles physics itself in that it
ruthlessly pares away the sort of detail historians rightly
consider essential in understanding a place and time. The
obligatory details and caveats of a truly historical exploration
would obscure the story I want to tell. I have tried to be
historically accurate, but I have only touched on the high
points, and the reader who wishes to savor the richness of the
history is referred to works recommended in the bibliography at
the end of the book. I have also pared away a great deal of
physics in the effort to make what is central to my discussion
more intelligible; more detailed discussions of the science are
recommended in the bibliography.
The reader is also entitled to know where the demarcation
lies between what is broadly accepted by the community of
physicists and the views that may be mine alone. By and large,
the story as it is developed here is not controversial. For
example, the interpretation of quantum mechanics given here
follows the lines laid down by the orthodox or "Copenhagen'
interpretation accepted by the great majority of physicists.
There are other ways of understanding quantum mechanics, but m
each case they are held by an extremely small, and in some cases
dwindling, minority. They are fun to think about, but I believe
the reader without a strong background in physics more likely
would be confused than enlightened by a discussion of these
esoteric interpretations. Again the bibliography points to works
that develop these ideas in greater detail.
I owe my recognition of the way language commits us to what
is real to the writings of W.V.O. Quine. My appreciation of the
implications of pragmatism was greatly enriched and deepened by
the writings of Richard Rorty.
It is a pleasure to acknowledge the people who made this book
possible. I benefited enormously from many conversations
throughout the years with Bob and Holly Doyle that shaped and
sharpened my understanding of the issues raised in the book.
Barbara Clark, Steve and Susan Gross, Linda Houck, James Jones
and Gail Hughes, Ken and Linda Schatz, and Susan Thomas provided
continuing support and encouragement. In addition, the Schatzes
introduced me to my agent, Michael Snell, who besides placing the
book gave me trenchant advice on how to write clearly and
effectively.
Myron Lecar read an early version of the manuscript, and
Holly Doyle, Don Lautman, Lynn Margulis, Matthew Schneps, Edward
Tripp, and Angela von der Lippe read later versions; they
provided helpful suggestions and badly needed encouragement. Owen
Gingerich, Lawrence Krauss, and Alan Lightman read parts of later
versions, pointing out ambiguities and mistakes and providing
helpful guidance. I also benefited greatly from the remarks of
several anonymous readers. Suggestions and queries from my editor
David Sobel resulted in a much more intelligible book than I
would have otherwise written. The book would have been much less
accurate and far more obscure were it not for several careful
readings of the manuscript by Irwin Shapiro. Any incoherencies or
muddles that remain do so despite his admonitions. I deeply
appreciate the time he gave to the project despite his
unreasonably busy schedule. I am grateful to Marian Shapiro for
providing the impetus to seek a publisher for the book.
My wife, the poet Gray Jacobik, provided constant support,
encouragement, and unfailingly perspicacious editorial advice.
Her keen understanding of the ways in which language works was
indispensable to developing the approach I take in this book. I
owe more to her than I can possibly express. I owe my
appreciation of the immense power of the myth of "is" to Werner
Erhard's relentless commitment to making a difference in my life.
Absent his unremitting efforts to uncover the role of speaking in
shaping experience, this book never would have been written.
To him who is a discoverer in this field, the products
of his imagination appear so necessary and natural that
he regards them, and would like to have them regarded
by others, not as crayons of thought but as given
realities.
ALBERT EINSTEIN
PROLOGUE
It is not nature that is economical, but science.
MAX BORN
Stand at the foot of a tall building, point a camera upward,
and take a picture. The picture will look badly distorted ' it
could hardly be called accurate. Yet there is nothing wrong with
the camera, and cameras normally do not lie. We have a convention
about how photographs of buildings 'ought' to look, and this
photograph violates that convention. The apparent distortion in
the photograph tells something about what we 'really" see. The
visual world is not a faithful reflection of the images on the
retinas of our eyes but a world somehow constructed out of such
images.
The American psychologist Adelbert Ames constructed a room
that appears to be normal when viewed from one perspective but
which, in face, is far from normal. For example, when people walk
from one side of a distant wan to another, they also move farther
from the viewer. Since they are moving away, the image on the
retina of the viewer's eyes grows smaller. Normally, without any
awareness on our part, we interpret this decrease in size in such
a way that we see the people as normal-sized but far away. This
room, however, is constructed so that the clues we ordinarily use
to assess size and distance are misleading. By a trick of
perspective, the distant wall seems to be perpendicular to the
line of sight. Accepting this perspective, we see the people, not
as farther away, but as smaller; they appear to shrink as they
move from one side of the room to the other and to grow larger as
they move back again. The illusion is almost as powerful in a
photograph. Even though we know that the changing size of people
in the Ames room is an illusion, there is nothing we can do about
it ' we continue to see the same bizarre world. How much of what
we see is similarly an "optical illusion" an interpretation
fabricated from our interaction with the world?
For a dog or a cat, no world at all seems to be revealed by
photograph albums and television sets ' our pets scarcely pay any
attention to these images. The worlds portrayed by photographs,
television, and movies are created by our interpretations ' in
this case, interpretations where language seems to have an
important role to play ' 'The picnic with my sister and her
family last Fourth of July.' It is not difficult to see that the
world revealed by television and newspapers is largely shaped by
language. To see the world in terms of Muslim fundamentalists,
Marxist guerrillas, or capitalist imperialists is certainly to
see a world shaped by language.
We also know that Ho we say things is important. Women are
different from girls, and homes can be different from houses. We
can even create things by saying certain words. When the umpire
says, "Safe!' he creates a score. When the foreman of the jury
says, "Guilty as charged,' she creates a felon. When two people
standing before a cleric say, "I will,' they create a marriage.
It may be harder to see the role that language plays in
shaping our motives and emotions, but it seems true that most of
what we call our feelings are interpretations we place on the
bodily sensations we have learned to identify with anger or
boredom or love. In this sense, the dog down the street may be
ferocious, but it seems unlikely that it is angry in the way
someone might be angry as a result of the way the IRS handled her
tax case. To the extent that our behavior is shaped by our
motives, feelings, and emotions, it seems fair to say that we
live in a world structured, at least to some degree, by language.
When we consider the physical world, we have a much harder
time seeing the role language plays. It seems obvious that there
is a physical world quite independent of what we say or do about
it. No matter how firmly someone believes he can fly simply by
flapping his arms, it is unwise to for him to step off the roof
of a tall building.
No matter how convinced a Buddhist is that the world is an
illusion, she invariably leaves a room by walking through the
doorway rather than through a wall. How does this physical world,
which seems so impervious to wishes and desires, relate to the
worlds shaped by language? One way to pursue this question is to
look at the history of how we came to know the things we know
about the physical world.
We normally think of science as the discovery of the facts
about the natural world and the laws that govern its behavior,
that is, we view science as the uncovering of an already-made
world. In this book, we will follow another course. We will trace
the history of physics as the evolution of a language ' as the
invention of new vocabularies and new ways of talking about the
world. Concentrating on the language physicists use to talk about
the world will establish a perspective, vitally important for
understanding the development of physics in the twentieth
century. But even more important, tracing the development of
physics will provide a powerful way of looking at the much
broader question of how language hooks up with the world.
Although it may be surprising at first, we will find that
physics is really not about making accurate pictures of the
world. If you go to an art gallery and ask yourself which of the
paintings are realistic and which are abstract, and why, you will
discover that realism in painting is largely a convention. A
physicist is no more engaged in painting a "realistic' picture of
the world than a "realistic' painter is. For a physicist, a
realistic picture is far too complex to be useful as a tool, and
physics is about fashioning tools.
In many ways, physics resembles abstract painting more than
it does photography. The world of physics is a world of hard
edges and abstraction ' a mathematical world as austere and as
beautiful as a painting by Mondrian. A world in which the
creativity and imagination of human beings is every bit as
important as they are in music or painting. We will follow the
story of men and women as they invent a language to empower
themselves in one dimension of the endless human project of
learning to deal with the world ' a project that can be traced
from the caves of Lascaux to the tunnels of Fermilab.
Chapter 1
IN THE BEGINNING
WAS THE
WORD . . .
It seems that the human mind has first to construct
forms independently before we can find them in things.
Kepler's marvelous achievement is a particularly fine
example of the truth that knowledge cannot spring from
experience alone, but only from the comparison of the
inventions of the mind with observed fact.
ALBERT EINSTEIN
Chapter 2
THE INVALUABLE
CONCEPT OF FORCE
Odd as it may seem, most people's views about motion
are part of a system of physics that was proposed more
than 2,000 years ago and was experimentally shown to be
inadequate at least 1,400 years ago
I. BERNARD COHEN
Chapter 3
THE INDISPENSABLE
IDEA OF FIELDS
A courageous scientific imagination was needed to
realize that not the behavior of bodies, but the
behavior of something between them, that is, the field,
may be essential for ordering and understanding events.
ALBERT EINSTEIN
Chapter 4
THE INGENIOUS
NOTION OF ATOMS
If in some cataclysm, all of scientific knowledge were
to be destroyed, and only one sentence passed on to the
next generation of creatures, what statement would
contain the most information with the fewest words?
RICHARD FEYNMAN
Chapter 5
THE UNIMAGINABLE
UNITY OF SPACETIME
No one must think that Newton's great creation can be
overthrown in any real sense by this or any other
theory. His clear and wide ideas will forever retain
their significance as the foundation on which our
modern conceptions of physics have been built.
ALBERT EINSTEIN
Chapter 6
THE IMPONDERABLE
NATURE OF MATTER
A new scientific truth does not triumph by convincing
its opponents and making them see light, but rather
because its opponents eventually die, and a new
generation grows up that is familiar with it.
MAX PLANCK
Chapter 7
THE INTRANSIGENT
PRESENCE OF PARADOX
Quality is reduced to quantity: The number of electrons
and the quantum numbers of a given state fully
determine all properties of the atom in that state. . .
the 'harmonies of the spheres' reappear in the world of
atoms. . .
VICTOR WEISSKOPF
Chapter 8
THE INEXHAUSTIBLE
FECUNDITY OF SPACE
Dick Feynman told me about his 'sum over histories'
version of quantum mechanics. 'The electron does
anything it likes," he said. 'It goes in any direction
at any speed, forward or backward in time, however it
likes, and then you add up the amplitudes and it gives
you the wave function.' I said to him, 'You're crazy.'
But he wasn't.
FREEMAN DYSON
Chapter 9
THE IMPROBABLE
PREVALENCE OF
SYMMETRY
Part of the art and skill of the engineer and of the
experimental physics is to create conditions in which
certain events are sure to occur.
EUGENE WIGNER
Chapter 10
W, Z Fields
Nature does not appear very simple or unified. . .
[but] we can at least make out the shape of symmetries,
which though broken, are exact principles governing all
phenomena, expressions of the beauty of the world . . .
STEVEN WEINBERG
Chapter 11
THE INEFFABLE COLOR
OF QUARKS
Science is the attempt to make the chaotic diversity of
our sense-experiences correspond to a logically uniform
system of thought.
ALBERT EINSTEIN
Chapter 12
THE UNQUESTIONABLE
IMAGINATION OF
PHYSICISTS
Our existing theories work well, which is certainly a
reason to be happy; but we should also be sad because
the fact that they work so well is now revealed as very
little assurance that any future theory will look at
all like them.
STEVEN VVEINBERG
Chapter 13
THE INSCRUTABLE
ESSENCE OF
MATHEMATICS
The miracle of the appropriateness of the language of
mathematics for the formulation of the laws of physics
is a wonderful gift which we neither understand nor
deserve.
EUGENE WIGNER
As far as the propositions of mathematics refer to
reality, they are not certain; and as far as they are
certain, they do not refer to reality.
ALBERT EINSTEIN
Chapter 14
THE UNSPEAKABLE
POWER OF LANGUAGE
The sense experiences are the given subject matter. But
the theory that shall interpret them is man-made. It is
the result of an extremely laborious process of
adaptation: hypothetical, never completely final,
always subject to question and doubt.
ALBERT EINSTEIN
End of part one