The Structure of Physics pptx

The Structure of Physics

Fundamental Theories of Physics

An International Book Series on The Fundamental Theories of Physics:

Their Clarification, Development and Application

Editor:

ALWYN VAN DER MERWE, University of Denver, U.S.A.

Editorial Advisory Board:

GIANCARLO GHIRARDI, University of Trieste, Italy

LAWRENCE P. HORWITZ, Tel-Aviv University, Israel

BRIAN D. JOSEPHSON, University of Cambridge, U.K.

CLIVE KILMISTER, University of London, U.K.

PEKKA J. LAHTI, University of Turku, Finland

FRANCO SELLERI, Università di Bara, Italy

TONY SUDBERY, University of York, U.K.

HANS-JÜRGEN TREDER, Zentralinstitut für Astrophysik der Akademie der

Wissenschaften, Germany

Volume 154

The Structure of Physics

by

Carl Friedrich von Weizsäcker

edited, revised and enlarged by

Thomas Görnitz

University of Frankfurt, Germany

Holger Lyre

University of Bonn, Germany

and

A C.I.P. Catalogue record for this book is available from the Library of Congress.

ISBN-10 1-4020-5234-0 (HB)

ISBN-13 978-1-4020-5234-7 (HB)

ISBN-10 1-4020-5235-9 (e-book)

ISBN-13 978-1-4020-5235-4 (e-book)

Published by Springer,

P.O. Box 17, 3300 AA Dordrecht, The Netherlands.

www.springer.com

Printed on acid-free paper

All Rights Reserved

© 2006 Springer

No part of this work may be reproduced, stored in a retrieval system, or transmitted

in any form or by any means, electronic, mechanical, photocopying, microfilming, recording

or otherwise, without written permission from the Publisher, with the exception

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Printed in the Netherlands.

Figures 6.7, 6.8, 6.9 and 6.10 (pp. 165 166) from Tonry, J.L. et al., Astrophysical Journal

Astrophysical Journal.

Original version: Aufbau der Physik, Hanser Verlag, Munich, 1985.

Translated into English by Helmut Biritz, Georgia Institute of Technology, School of Physics,

Atlanta, USA.

–

594 (2003), 1-24, have been used with the kind permission of Dr. B. Leibundgut and the

Albert Einstein

Niels Bohr

Werner Heisenberg

Contents

1 Introduction ............................................... 1

1.1 The question. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Part I The unity of physics

2 The system of theories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2.1 Preliminary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2.2 Classical point mechanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2.3 Mathematical forms of the laws of nature . . . . . . . . . . . . . . . . . . . 28

2.4 Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.5 Thermodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2.6 Field theories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.7 Non-Euclidean geometry and semantic consistency . . . . . . . . . . . 35

2.8 The relativity problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.9 Special theory of relativity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

2.10 General theory of relativity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

2.11 Quantum theory, historical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

2.12 Quantum theory, plan of reconstruction . . . . . . . . . . . . . . . . . . . . 54

Editors’ Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

Preface (1985) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii

On Weizs¨acker’s philosophy of physics (by H. Lyre) . . . . . . . . . . . . xix

vii

Contents

3 Probability and abstract quantum theory . . . . . . . . . . . . . . . . . . 59

3.1 Probability and experience. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

3.2 The classical concept of probability . . . . . . . . . . . . . . . . . . . . . . . . 62

3.3 Empirical determination of probabilities . . . . . . . . . . . . . . . . . . . . 66

3.4 Second quantization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

3.5 Methodological: Reconstruction of abstract quantum theory . . 71

3.6 Reconstruction via probabilities and the lattice of propositions 73

4 Quantum theory and spacetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

4.1 Concrete quantum theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

4.2 Reconstruction of quantum theory via variable alternatives . . . 85

4.3 Space and time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

5 Models of particles and interaction . . . . . . . . . . . . . . . . . . . . . . . . 105

5.1 Open questions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

5.2 Representations in tensor space . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

5.3 Quasiparticles in rigid coordinate spaces . . . . . . . . . . . . . . . . . . . . 117

5.4 Model of quantum electrodynamics . . . . . . . . . . . . . . . . . . . . . . . . 123

5.5 Elementary particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

5.6 General theory of relativity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

6 Cosmology and particle physics (by Th. G¨ornitz) . . . . . . . . . . 149

6.1 Quantum theory of abstract binary alternatives and cosmology 149

6.2 Ur-theoretic vacuum and particle states . . . . . . . . . . . . . . . . . . . . 169

6.3 Relativistic particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

6.4 Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

Part II Time and information

7 Irreversibility and entropy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

7.1 Irreversibility as problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

7.2 A model of irreversible processes . . . . . . . . . . . . . . . . . . . . . . . . . . 187

7.3 Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

7.4 Cosmology and the theory of relativity . . . . . . . . . . . . . . . . . . . . . 201

8 Information and evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

8.1 The systematic place of the chapter . . . . . . . . . . . . . . . . . . . . . . . . 211

8.2 What is information? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

8.3 What is evolution? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

8.4 Information and probability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

8.5 Evolution as growth of potential information . . . . . . . . . . . . . . . . 218

8.6 Pragmatic information: Novelty and confirmation . . . . . . . . . . . . 229

8.7 Biological preliminaries to logic . . . . . . . . . . . . . . . . . . . . . . . . . . . 234

viii

Contents

Part III On the interpretation of physics

9 The problem of the interpretation of quantum theory. . . . . . 243

9.1 About the history of the interpretation . . . . . . . . . . . . . . . . . . . . . 243

9.2 The semantic consistency of quantum theory . . . . . . . . . . . . . . . . 260

9.3 Paradoxes and alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

10 The stream of information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

10.1 The quest for substance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

10.2 The stream of information in quantum theory . . . . . . . . . . . . . . . 300

10.3 Mind and form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306

11 Beyond quantum theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311

11.1 Crossing the frontier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311

11.2 Facticity of the future . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316

11.3 Possibility of the past . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321

11.4 Comprehensive present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 327

11.5 Beyond physics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330

12 In the language of philosophers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

12.1 Exposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

12.2 Philosophy of science . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 334

12.3 Physics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337

12.4 Metaphysics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353

ix

Carl Friedrich von Weizs¨acker is certainly one of the most distinguished Ger￾man physicists and philosophers of the 20th century—equally renowned for his

early contributions to nuclear physics and his life-long research on the founda￾tions of quantum theory. At the same time, Weizs¨acker is highly esteemed by

a much broader audience for his sociocultural, political, and religious thought.

His writings comprise more than 20 books, many of which have been trans￾lated into several languages.

But throughout his life, Weizs¨acker’s main concern was an understanding

of the unity of physics. For decades he and his collaborators have been pursu￾ing the idea of a quantum theory of binary alternatives (so-called ur theory),

a unified quantum theoretical framework in which spinorial symmetry groups

are considered to give rise to the structure of space and time. Aufbau der

Physik, first published exactly 20 years ago, in 1985, and followed by numerous

reprints, was primarily intended to give an overview and update of this enter￾prise. But the book was only published in German, and thus could scarcely

have contained the subsequent insights and results of ur-theoretic research of

the late 1980s and the 1990s, due mainly to the work of Thomas G¨ornitz.

These circumstances were the main incentive for producing the present edi￾tion, which is a newly arranged and revised version of the Aufbau, translated

into English, in which some original chapters and sections have been skipped,

and a new chapter on ur theory and a general introduction to Weizs¨acker’s

philosophy of physics have been added. A comparison of the present book’s

structure to that of the original book can be found on page XIV, footnote 2).

The Structure of Physics should be of value to anybody with interests

in physics, its history, or its philosophy, since it contains far more than the

particular focus on ur theory in the central Chaps. 4, 5, and 6 of the first

part. As a prominent eyewitness to the historical development of quantum

mechanics, Weizs¨acker’s presentation of the system of physical theories in the

second chapter and his way of presenting the general interpretive issues of

quantum mechanics in Chap. 9 are both of special importance. Furthermore,

Weizs¨acker’s discussion of time and information in the second part, along with

xi

Editors’ Preface

his analyses in the last three chapters of the third part, reveal him to be an

original and outstanding philosophical thinker.

We are very grateful to the many people and institutions without whom

the present edition would have been impossible: the Kluwer and Springer

publishing houses for adopting the project; the Carl Friedrich von Weizs¨acker￾Stiftung—in particular Bruno Redeker—for administrative support; and the

Udo Keller Stiftung Forum Humanum for a generous donation.

The Udo Keller Stiftung Forum Humanum is located in Neversdorf

(Schleswig-Holstein, Germany). In reconsidering religion and spiritual￾ity, it is dedicated to the crucial questions of human life. In doing so,

the foundation is not committed to a particular doctrine or world view.

Rather, it strives for deepers insight into the limits, contradictions, and

possibilities of human knowledge. Its goal is a sensible dialog among the

humanities, natural sciences, and the world religions.

In this way the Udo Keller Stiftung Forum Humanum supports a multi￾tude of projects, and collaborates in particular with the Weltethos Foun￾dation directed by Prof. Hans K¨ung, the Carl Friedrich von Weizs¨acker

Foundation, and the Carl Friedrich von Weizs¨acker Society.

Special thanks are due to Helmut Biritz, who provided a careful translation

of the Aufbau and who was both a pleasant and patient collaborator. It is our

hope that this edition will help to make Weizs¨acker’s unique ideas in the

philosophy of physics more accessible to the English-speaking world.

Pentecost 2005 Thomas G¨ornitz

Holger Lyre

xii Editors’ Preface

Preface (1985)

The book reports on an attempt to understand the unity of physics. This unity

began to manifest itself in rather unexpected form in this century. The most

important step in that direction was the development of quantum theory; the

emphasis of this book is therefore on the endeavor to understand quantum

theory. Here, understand refers not merely to practical application of the

theory—in that sense it has been understood for a long time. It means being

able to say what one does when applying the theory. This endeavor has led

me, on the one hand, to reflect upon the foundations of probability theory

and the logic of temporal propositions, and on the other to progress to what

appears to me a promising attempt to generalize the theory in such a way that

relativity and the basic ideas of elementary particle theory could be derived

from it. If this attempt were successful, we would come one step closer to

the actual unity of physics as an understood theory. The understanding of

the unity of physics is on the other hand no doubt a prerequisite for insight

into its philosophical meaning and its role in our endeavor to perceive the

oneness of reality. This might finally be necessary if we wish to comprehend

the significance of natural science in the cultural development of our times,

as a key to deep, effective, and perilous insights.

I have placed the three names Albert Einstein, Niels Bohr, Werner Heisen￾berg at the head of the book. Einstein was the genius of the century. The

theory of relativity is his work, and it was on his account that quantum the￾ory got under way. All younger workers remain under the spell cast by his

insights. Bohr was the inquiring master of atomic theory. He pressed onward

into realms from which Einstein shut himself off; the completion of quantum

theory was the handiwork of his followers. Heisenberg, with matrix mechanics,

took the first steps on solid ground. Among the generation of the creators of

quantum theory he was primus inter pares. As his equals one might perhaps

mention Dirac, Pauli, and Fermi. The creation of the new physics was a collec￾tive undertaking. Indispensable work was carried out by Planck, who opened

the door to quantum theory; by Rutherford, who in the experimental inves￾tigation of atoms was the master and teacher that his student Bohr became

xiii

Preface (1985)

in theory; by Sommerfeld, de Broglie, and Schr¨odinger; by Born and Jordan;

and by a great many more experimentalists.

For me, the mention of these three names also carries the personal signif￾icance of admiring and affectionate remembrance. I unfortunately never met

Einstein, but his name was familiar to me by the time I was a schoolboy, and

from decade to decade I learned to better understand his greatness. When

I was nineteen years old, Bohr revealed to me the philosophical dimension

of physics. He gave me what I had been looking for in physics. From him I

learned to understand the influence that Socrates must have exerted over his

followers. I had the good fortune to meet Heisenberg when I was fifteen. He

brought me into physics, taught me its craft and its beauty, and became a

lifelong friend.1

One might perhaps mention here an amusing play on round numbers:

without being pre-planned as such, the present book will be published, almost

to the day, on Bohr’s one-hundredth birthday, October 7, 1985. Sixty years ago

(Pentecost 1925) Heisenberg, while in Helgoland, discovered the foundations

of quantum mechanics. Fifty years ago (1935) Einstein published his quantum

mechanics thought experiment with co-authors Podolsky and Rosen.

As for the genesis of this book, when the investigations reported here

began, the work of the pioneers had long since come to a close. Heisenberg

told me as early as April 1927, two months after we first met, about his

yet-unpublished uncertainty relations. From that time onward I wanted to

study physics to understand quantum theory. But the longer I was a physicist

the clearer it became to me that I still did not understand the theory. In

1954 I came to the conclusion that the classical horizon of thought must be

transcended even in the realm of logic; about 1963 I realized that this had to

do with the logic of time. Both steps were prepared. The central role of time

became clear to me in a study of the second law of thermodynamics (1939),

described in this book in Chap. 4.2

1 I might very well mention here more elaborate accounts of the three: Ein￾stein (1979), Bohr und Heisenberg: Eine Erinnerung aus dem Jahr 1932 (1982),

Werner Heisenberg (1977, 1985). References can be found in the bibliography. 2 Editors’ note: Weizs¨acker refers to the original Aufbau, the present book has the

following, different arrangement:

Chapter 1: Aufbau 1.1, 1.3,

Chapter 2: Aufbau 6

Chapter 3: Aufbau 3.1–3.3, 7.4, 8.1–8.2,

Chapter 4: Aufbau 9,

Chapter 5: Aufbau 10.1–10.2, 10.4–10.7,

Chapter 6: new (by Th. G¨ornitz),

Chapter 7: Aufbau 4,

Chapter 8: Aufbau 5.1–5.5, 5.7–5.8,

Chapter 9: Aufbau 11,

Chapter 10: Aufbau 12,

xiv

Preface (1985)

I have written philosophical essays on quantum theory since 1931, with

the more tenable ones being published in the book Zum Weltbild der Physik

(1943, finished 1957, 7th edition). The path to the logical interpretation is

now described in 7.7. Only after I had found this interpretation could I—that

was my feeling—make firm progress. But the road was very long. In 1971 I

published an interim report in the book Die Einheit der Natur, still only a

collection of essays. Since then I have continued working steadily.

The length of the path was due in part to the difficulty of the subject

matter, and in part to the limitations of my mathematical ability. Had more

colleagues been interested in this research the mathematical problems could

have been solved much sooner, but I could not arouse their curiosity. The

path of this reflection lay beyond the successful line of approach of the topical

research in physics. Even Heisenberg, who always wanted to stay informed on

the progress and problems of my work, told me: “You are on a good track,

but I cannot help you. I cannot think so abstractly.” Success alone rouses

the productive curiosity of scientists, and I needed the help of that curiosity

before success could follow. On the other hand, the apparent distractions in

my life due to politics and philosophy only slightly slowed the pace of this

work. Philosophy was indispensable for a philosophically oriented analysis of

physics; attempting to understand Plato, Aristotle, Descartes, Kant, Frege

or Heidegger was no distraction at all from the main topic, and hence en￾tailed no loss of time. Politics was a different matter. But for me it would

have been morally impossible to do physics while ignoring political, proba￾bly catastrophic consequences of physical research. Politics cost me perhaps a

total of ten working years, perhaps more. Yet alongside politics the work con￾tinued steadily; subconscious contemplation does not stop when other matters

temporarily occupy the conscious mind. Worse, though, was the inevitability

of political failure, given the prevailing denial of inherent risks.

The work is not finished. I am writing this account with the feeling that

there is probably not much time left to me, partly on account of my age, and

partly in view of the uncertain times. In contrast to Einheit der Natur, this

book is designed as a single continuous train of thought. One shortcoming

is its bulk. Apparently I had needed to portray many details and to follow

many and varied alternative paths to attain a clear view of the entire subject,

which might ultimately have enabled me to say everything in a fraction of the

present scope. But, with novel thoughts, a more elaborate presentation might

help the reader’s comprehension. At any rate, I have never striven for that

hermetical terseness so prevalent in mathematics.

The amount of material has led this report being divided into two books.

The present book, appearing first, portrays in one direct progression the re￾construction of physics that I aspire to. I have also chosen Aufbau der Physik

as its title. Einheit der Physik (The Unity of Physics) would have been factu￾Chapter 11: Aufbau 13,

Chapter 12: Aufbau 14.

xv

Preface (1985)

ally more accurate, but I avoided that title solely to preclude confusion with

Einheit der Natur (The Unity of Nature). A second book, under the title Zeit

und Wissen (Time and Knowledge), will contain philosophical reflections. At

present I am undecided as to whether that latter book will also be subdivided.

This book is a research report and not a textbook. It therefore requires

of the reader certain prior knowledge of the topics under consideration. But I

have taken pains to develop the physical and philosophical ideas broadly, and

to avoid mathematical details as much as possible. An expert will be able to fill

in mathematical details; they would remain incomprehensible to the layman.

I do not deny, however, that in the verbal presentation, the only one I was

capable of, there might be hidden unresolved mathematical problems that I

myself have not sufficiently recognized. Chapters 1 to 6, 12, and 14 should be

immediately readable by a natural scientist or philosopher reasonably familiar

with physics. Chapters 7–11 and 13 assume a knowledge of quantum theory.

Material spanning about twenty years was available for this book. I have

not attempted to write everything anew but used some of those materials

verbatim. Hence there remains a certain unevenness, and repetitions of the

same ideas in different contexts. Some of the texts are more pedagogically

formulated, others are more like technical reports or programmatic. The reader

will more easily orient himself by being able to keep them apart. For this I

have identified each of the old texts according to their date of origin and first

usage. In brief: Chaps. 2 and 4 are from a first draft of the book written in

1965, in the form of a lecture. In Chap. 3 the older formulation has been

replaced by texts from around 1970. A few texts from the 1970s or reports of

such are contained in Chaps. 5–7 and 12. Chapters 1, 8–10, 13, and 14 have

been written anew. The texts are now incorporated into a continuous train of

thought, with the exception of Chaps. 2–4, which were already coherent.

The investigations described here would not have been possible without

decades of collaboration. The first more elaborate publication, in 1958, was

coauthored by E. Scheibe and G. S¨ußmann. R. Ebert participated in the daily

discussions at that time. The thesis of H. Kunsem¨uller contributed to the un￾derstanding of quantum logic. K. M. Meyer-Abich clarified the genesis and

meaning of the basic concepts of N. Bohr. From 1965 through 1978 M. Dri￾eschner carried out a significant part of the work on probability, irreversibility,

and the axiomatic foundations of quantum theory. F. J. Zucker, during his stay

in Germany, contributed substantially—along with philosophical ideas—to an

understanding of the concept of information,, as did E. and C. v. Weizs¨acker

in the Heidelberg “Offene Systeme” discussion group. In America F. J. Zucker

then established contacts, in part through an exemplary translation of Einheit

der Natur. L. Castell provided an essential stimulus in 1968 and for all further

investigations by introducing group-theoretical ways of thinking. From 1970

through 1984 he led the Starnberg group; essential parts of Chaps. 9–10 are

reports on his work and that of his students. Among external contacts, discus￾sions with H.-P. D¨urr spanning decades were essential. In 1971 I encountered

in D. Finkelstein the only physicist who, independently of us, had developed

xvi