FRITJOF CAPRA

The Tao of Physics

An exploration of the parallels between modern physics and Eastern mysticism

I dedicate this book to

Ali Akbar Khan

Carlos Castaneda

Geoffrey Chew

John Coltrane

Werner Heisenberg

Krishnamurti

Liu Hsiu Ch’i

Phiroz Mehta

Jerry Shesko

Bobby Smith

Maria Teuffenbach

Alan Watts

for helping me to find my path

and to Jacqueline

who has travelled with me

on this path

most of the time.

Contents

Preface

Preface to the Second Edition

I The Way of Physics

Chapter 1 Modern Physics—A Path with a Heart?

Chapter 2 Knowing and Seeing

Chapter 3 Beyond Language

Chapter 4 The New Physics

II The Way of Eastern Mysticism

Chapter 5 Hinduism

Chapter 6 Buddhism

Chapter 7 Chinese Thought

Chapter 8 Taosim

Chapter 9 Zen

III The Parallels

Chapter 10 The Unity of All Things

Chapter 11 Beyond the World of Opposites

Chapter 12 Space-time

Chapter 13 The Dynamic Universe

Chapter 14 Emptiness and Form

Chapter 15 The Cosmic Dance

Chapter 16 Quark Symmetries—A New Koan?

Chapter 17 Patterns of Change

Chapter 18 Interpenetration

Epilogue

The New Physics Revisited Afterword to the Second Edition

The Future of the New Physics Afterword to the Third Edition

Notes

Bibliography

Index

Acknowledgments

About the Author

Also by Fritjof Capra

Copyright

About the Publisher

It is probably true quite generally that in the history of human thinking the most fruitful developments frequently take place at those points where two different lines of thought meet. These lines may have their roots in quite different parts of human culture, in different times or different cultural environments or different religious traditions: hence if they actually meet, that is, if they are at least so much related to each other that a real interaction can take place, then one may hope that new and interesting developments may follow.

Werner Heisenberg

Preface

Five years ago, I had a beautiful experience which set me on a road that has led to the writing of this book. I was sitting by the ocean one late summer afternoon, watching the waves rolling in and feeling the rhythm of my breathing when I suddenly became aware of my whole environment as being engaged in a gigantic cosmic dance. Being a physicist, I knew that the sand, rocks, water and air around me were made of vibrating molecules and atoms, and that these consisted of particles which interacted with one another by creating and destroying other particles. I knew also that the Earth’s atmosphere was continually bombarded by showers of ‘cosmic rays’, particles of high energy undergoing multiple collisions as they penetrated the air. All this was familiar to me from my research in high-energy physics, but until that moment I had only experienced it through graphs, diagrams and mathematical theories. As I sat on that beach my former experiences came to life; I ‘saw’ cascades of energy coming down from outer space, in which particles were created and destroyed in rhythmic pulses; I ‘saw’ the atoms of the elements and those of my body participating in this cosmic dance of energy; I felt its rhythm and I ‘heard’ its sound, and at that moment I knew that this was the Dance of Shiva, the Lord of Dancers worshipped by the Hindus.

I had gone through a long training in theoretical physics and had done several years of research. At the same time, I had become very interested in Eastern mysticism and had begun to see the parallels to modern physics. I was particularly attracted to the puzzling aspects of Zen which reminded me of the puzzles in quantum theory. At first, however, relating the two was a purely intellectual exercise. To overcome the gap between rational, analytical thinking and the meditative experience of mystical truth, was, and still is, very difficult for me.

In the beginning I was helped on my way by ‘power plants’ which showed me how the mind can flow freely; how spiritual insights come on their own, without any effort, emerging from the depth of consciousness. I remember the first such experience. Coming, as it did, after years of detailed analytical thinking it was so overwhelming that I burst into tears, at the same time, not unlike Castaneda, pouring out my impressions on to a piece of paper.

Later came the experience of the Dance of Shiva which I have tried to capture in the photomontage shown in Plate 7. It was followed by many similar experiences which helped me gradually to realize that a consistent view of the world is beginning to emerge from modern physics which is harmonious with ancient Eastern wisdom. I took many notes over the years, and wrote a few articles about the parallels I kept discovering, until I finally summarized my experiences in the present book.

This book is intended for the general reader with an interest in Eastern mysticism who need not necessarily know anything about physics. I have tried to present the main concepts and theories of modern physics without any mathematics and in non-technical language, although a few paragraphs may still appear difficult to the layperson at first reading. The technical terms I had to introduce are all defined where they appear for the first time and are listed in the index at the end of the book.

I also hope to find among my readers many physicists with an interest in the philosophical aspects of physics, who have as yet not come in contact with the religious philosophies of the East. They will find that Eastern mysticism provides a consistent and beautiful philosophical framework which can accommodate our most advanced theories of the physical world.

As far as the contents of the book are concerned, the reader may feel a certain lack of balance between the presentation of scientific and mystical thought. Throughout the book, his or her understanding of physics should progress steadily, but a comparable progression in the understanding of Eastern mysticism may not occur. This seems unavoidable, as mysticism is, above all, an experience that cannot be learned from books. A deeper understanding of any mystical tradition can only be felt when one decides to become actively involved in it. All I can hope to do is to generate the feeling that such an involvement would be highly rewarding.

During the writing of this book, my own understanding of Eastern thought has deepened considerably. For this I am indebted to two men who come from the East. I am profoundly grateful to Phiroz Mehta for opening my eyes to many aspects of Indian mysticism, and to my T’ai Chi master Liu Hsiu Ch’i for introducing me to living Taoism.

It is impossible to mention the names of everyone—scientists, artists, students, and friends—who have helped me formulate my ideas in stimulating discussions. I feel, however, that I owe special thanks to Graham Alexander, Jonathan Ashmore, Stratford Caldecott, Lyn Gambles, Sonia Newby, Ray Rivers, Joël Scherk, George Sudarshan, and—last but not least—Ryan Thomas.

Finally, I am indebted to Mrs Pauly Bauer-Ynnhof of Vienna for her generous financial support at a time when it was needed most.

London, December 1974 Fritjof Capra

Preface to the Second Edition

This book was first published seven years ago, and it originated in an experience, as described in the preceding preface, that now lies more than ten years in the past. It seems thus appropriate that I should say a few words to the readers of this new edition about the many things that have happened in those years—to the book, to physics, and to myself.

When I discovered the parallels between the world views of physicists and mystics, which had been hinted at before but never thoroughly explored, I had the strong feeling that I was merely uncovering something that was quite obvious and would be common knowledge in the future; and sometimes, while writing The Tao of Physics, I even felt that it was being written through me, rather than by me. The subsequent events have confirmed these feelings. The book has been received enthusiastically in the United Kingdom and the United States. Though it had only minimal promotion or advertising, it spread rapidly by word of mouth and is now available, or being published, in a dozen editions around the world.

The reaction of the scientific community, predictably, has been more cautious; but there, too, the interest in the broader implications of twentieth-century physics is increasing. The reluctance of modern scientists to accept the profound similarities between their concepts and those of mystics is not surprising, since mysticism—at least in the West—has traditionally been associated, quite erroneously, with things vague, mysterious, and highly unscientific. Fortunately, this attitude is now changing. As Eastern thought has begun to interest a significant number of people and meditation is no longer viewed with ridicule or suspicion, mysticism is being taken seriously even within the scientific community.

The success of The Tao of Physics has had a strong impact on my life. During the past years, I have travelled extensively, lecturing to professional and lay audiences and discussing the implications of the ‘new physics’ with men and women from all walks of life. These discussions have helped me tremendously in understanding the broader cultural context of the strong interest in Eastern mysticism that arose in the West during the last twenty years. I now see this interest as part of a much larger trend which attempts to counteract a profound imbalance in our culture—in our thoughts and feelings, our values and attitudes, and our social and political structures. I have found the Chinese terminology of yin and yang very useful to describe this cultural imbalance. Our culture has consistently favoured yang, or masculine, values and attitudes, and has neglected their complementary yin, or feminine, counterparts. We have favoured self-assertion over integration, analysis over synthesis, rational knowledge over intuitive wisdom, science over religion, competition over cooperation, expansion over conservation, and so on. This one-sided development has now reached a highly alarming stage; a crisis of social, ecological, moral and spiritual dimensions.

However, we are witnessing, at the same time, the beginning of a tremendous evolutionary movement that seems to illustrate the ancient Chinese saying that ‘the yang, having reached its climax, retreats in favour of the yin.’ The 1960s and 1970s have generated a whole series of social movements which all seem to go in the same direction. The rising concern with ecology, the strong interest in mysticism, the growing feminist awareness, and the rediscovery of holistic approaches to health and healing are all manifestations of the same evolutionary trend. They all counteract the overemphasis of rational, masculine attitudes and values, and attempt to regain a balance between the masculine and feminine sides of human nature. Thus, the awareness of the profound harmony between the world view of modern physics and the views of Eastern mysticism now appears as an integral part of a much larger cultural transformation, leading to the emergence of a new vision of reality that will require a fundamental change in our thoughts, perceptions and values. In my second book, The Turning Point, I have explored the various aspects and implications of this cultural transformation.

The fact that the current changes in our value system will affect many of our sciences may seem surprising to those who believe in an objective, value-free science. It is, however, one of the important implications of the new physics. Heisenberg’s contributions to quantum theory, which I discuss in great detail in this book, imply clearly that the classical ideal of scientific objectivity can no longer be maintained, and thus modern physics is also challenging the myth of a value-free science. The patterns scientists observe in nature are intimately connected with the patterns of their minds; with their concepts, thoughts and values. Hence, the scientific results they obtain and the technological applications they investigate will be conditioned by their frame of mind. Although much of their detailed research will not depend explicitly on their value system, the larger framework within which this research is pursued will never be value free. Scientists, therefore, are responsible for their research not only intellectually but also morally.

From this point of view, the connection between physics and mysticism is not only very interesting but also extremely important. It shows that the results of modern physics have opened up two very different paths for scientists to pursue. They may lead us—to put it in extreme terms—to the Buddha or to the Bomb, and it is up to each scientist to decide which path to take. It seems to me that at a time when close to half of our scientists and engineers work for the military, wasting an enormous potential of human ingenuity and creativity by developing ever more sophisticated means of total destruction, the path of the Buddha, the ‘path with a heart’, cannot be overemphasized.

The present edition of this book has been updated by including results from the most recent research in subatomic physics. I have done this by slightly changing certain passages in the text to make them more consistent with the new research, and by adding a new section at the end of the book, entitled The New Physics Revisited’, in which the most important new developments in subatomic physics are described in some detail. It has been very gratifying for me that none of these recent developments has invalidated anything I wrote seven years ago. In fact, most of them were anticipated in the original edition. This has confirmed the strong belief that motivated me to write the book—that the basic themes which I use in my comparison between physics and mysticism will be enforced, rather than invalidated, by future research.

Moreover, I now feel on much firmer ground with my thesis because the parallels to Eastern mysticism are appearing not only in physics but also in biology, psychology and other sciences. In studying the relationships between physics and those sciences, I have found that a natural extension of the concepts of modern physics to other fields is provided by the framework of systems theory. The exploration of systems concepts in biology, medicine, psychology, and in the social sciences, which I have undertaken in The Turning Point, has shown me that the systems approach strongly enforces the parallels between modern physics and Eastern mysticism. In addition, the new systems biology and psychology point to other similarities with mystical thought that lie outside the subject matter of physics. Those discussed in my second book include certain ideas about free will, death and birth, and the nature of life, mind, consciousness and evolution. The profound harmony between these concepts, as expressed in systems language, and the corresponding ideas in Eastern mysticism, is impressive evidence for my claim that the philosophy of mystical traditions, also known as the ‘perennial philosophy’, provides the most consistent philosophical background to our modern scientific theories.

Berkeley, June 1982 Fritjof Capra

I The Way of Physics

Chapter 1 Modern Physics – A Path with a Heart?

Any path is only a path, and there is no affront, to oneself or to others, in dropping it if that is what your heart tells you … Look at every path closely and deliberately. Try it as many times as you think necessary. Then ask yourself, and yourself alone, one question … Does this path have a heart? If it does, the path is good; if it doesn’t it is of no use.

Carlos Castaneda, The Teachings of Don Juan

Modern physics has had a profound influence on almost all aspects of human society. It has become the basis of natural science, and the combination of natural and technical science has fundamentally changed the conditions of life on our earth, both in beneficial and detrimental ways. Today, there is hardly an industry that does not make use of the results of atomic physics, and the influence these have had on the political structure of the world through their application to atomic weaponry is well known. However, the influence of modern physics goes beyond technology. It extends to the realm of thought and culture where it has led to a deep revision in our conception of the universe and of our relation to it. The exploration of the atomic and subatomic world in the twentieth century has revealed an unsuspected limitation of classical ideas, and has necessitated a radical revision of many of our basic concepts. The concept of matter in subatomic physics, for example, is totally different from the traditional idea of a material substance in classical physics. The same is true for concepts like space, time, or cause and effect. These concepts, however, are fundamental to our outlook on the world around us and with their radical transformation our whole world view has begun to change.

These changes, brought about by modern physics, have been widely discussed by physicists and by philosphers over the past decades, but very seldom has it been realized that they all seem to lead in the same direction, towards a view of the world which is very similar to the views held in Eastern mysticism. The concepts of modern physics often show surprising parallels to the ideas expressed in the religious philosophies of the Far East. Although these parallels have not, as yet, been discussed extensively, they have been noticed by some of the great physicists of our century when they came in contact with Far Eastern culture during their lecture tours to India, China and Japan. The following three quotations serve as examples:

The general notions about human understanding … which are illustrated by discoveries in atomic physics are not in the nature of things wholly unfamiliar, wholly unheard of, or new. Even in our own culture they have a history, and in Buddhist and Hindu thought a more considerable and central place. What we shall find is an exemplification, an encouragement, and a refinement of old wisdom.¹

Julius Robert Oppenheimer

For a parallel to the lesson of atomic theory … [we must turn] to those kinds of epistemological problems with which already thinkers like the Buddha and Lao Tzu have been confronted, when trying to harmonize our position as spectators and actors in the great drama of existence.²

Niels Bohr

The great scientific contribution in theoretical physics that has come from Japan since the last war may be an indication of a certain relationship between philosophical ideas in the tradition of the Far East and the philosophical substance of quantum theory.³

Werner Heisenberg

The purpose of this book is to explore this relationship between the concepts of modern physics and the basic ideas in the philosophical and religious traditions of the Far East. We shall see how the two foundations of twentieth-century physics—quantum theory and relativity theory—both force us to see the world very much in the way a Hindu, Buddhist or Taoist sees it, and how this similarity strengthens when we look at the recent attempts to combine these two theories in order to describe the phenomena of the submicroscopic world: the properties and interactions of the subatomic particles of which all matter is made. Here the parallels between modern physics and Eastern mysticism are most striking and we shall often encounter statements where it is almost impossible to say whether they have been made by physicists or by Eastern mystics.

When I refer to ‘Eastern mysticism’, I mean the religious philosophies of Hinduism, Buddhism and Taoism. Although these comprise a vast number of subtly interwoven spiritual disciplines and philosophical systems, the basic features of their world view are the same. This view is not limited to the East, but can be found to some degree in all mystically oriented philosophies. The argument of this book could therefore be phrased more generally, by saying that modern physics leads us to a view of the world which is very similar to the views held by mystics of all ages and traditions. Mystical traditions are present in all religions, and mystical elements can be found in many schools of Western philosophy. The parallels to modern physics appear not only in the Vedas of Hinduism, in the I Ching, or in the Buddhist sutras, but also in the fragments of Heraclitus, in the Sufism of Ibn Arabi, or in the teachings of the Yaqui sorcerer Don Juan. The difference between Eastern and Western mysticism is that mystical schools have always played a marginal role in the West, whereas they constitute the mainstream of Eastern philosophical and religious thought. I shall therefore, for the sake of simplicity, talk about the ‘Eastern world view’ and shall only occasionally mention other sources of mystical thought.

If physics leads us today to a world view which is essentially mystical, it returns, in a way, to its beginning 2,500 years ago. It is interesting to follow the evolution of Western science along its spiral path, starting from the mystical philosophies of the early Creeks, rising and unfolding in an impressive development of intellectual thought that increasingly turned away from its mystical origins to develop a world view which is in sharp contrast to that of the Far East. In its most recent stages, Western science is finally overcoming this view and coming back to those of the early Creek and the Eastern philosophies. This time, however, it is not only based on intuition, but also on experiments of great precision and sophistication, and on a rigorous and consistent mathematical formalism.

The roots of physics, as of all Western science, are to be found in the first period of Creek philosophy in the sixth century B.C., in a culture where science, philosophy and religion were not separated. The sages of the Milesian school in Ionia were not concerned with such distinctions. Their aim was to discover the essential nature, or real constitution, of things which they called ‘physis’. The term ‘physics’ is derived from this Greek word and meant therefore, originally, the endeavour of seeing the essential nature of all things.

This, of course, is also the central aim of all mystics, and the philosophy of the Milesian school did indeed have a strong mystical flavour. The Milesians were called ‘hylozoists’, or ‘those who think matter is alive’, by the later Greeks, because they saw no distinction between animate and inanimate, spirit and matter. In fact, they did not even have a word for matter, since they saw all forms of existence as manifestations of the ‘physis’, endowed with life and spirituality. Thus Thales declared all things to be full of gods and Anaximander saw the universe as a kind of organism which was supported by ‘pneuma’, the cosmic breath, in the same way as the human body is supported by air.

The monistic and organic view of the Milesians was very close to that of ancient fndian and Chinese philosophy, and the parallels to Eastern thought are even stronger in the philosophy of Heraclitus of Ephesus. Heraclitus believed in a world of perpetual change, of eternal ‘Becoming’. For him, all static Being was based on deception and his universal principle was fire, a symbol for the continuous flow and change of all things. Heraclitus taught that all changes in the world arise from the dynamic and cyclic interplay of opposites and he saw any pair of opposites as a unity. This unity, which contains and transcends all opposing forces, he called the Logos.

The split of this unity began with the Eleatic school, which assumed a Divine Principle standing above all gods and men. This principle was first identified with the unity of the universe, but was later seen as an intelligent and personal God who stands above the world and directs it. Thus began a trend of thought which led, ultimately, to the separation of spirit and matter and to a dualism which became characteristic of Western philosophy.

A drastic step in this direction was taken by Parmenides of Elea who was in strong opposition to Heraclitus. He called his basic principle the Being and held that it was unique and invariable. He considered change to be impossible and regarded the changes we seem to perceive, in the world as mere illusions of the senses. The concept of an indestructible substance as the subject of varying properties grew out of this philosophy and became one of the fundamental concepts of Western thought.

In the fifth century B.C., the Greek philosophers tried to overcome the sharp contrast between the views of Parmenides and Heraclitus. In order to reconcile the idea of unchangeable Being (of Parmenides) with that of eternal Becoming (of Heraclitus), they assumed that the Being is manifest in certain invariable substances, the mixture and separation of which gives rise to the changes in the world. This led to the concept of the atom, the smallest indivisible unit of matter, which found its clearest expression in the philosophy of Leucippus and Democritus. The Greek atomists drew a clear line between spirit and matter, picturing matter as being made of several ‘basic building blocks’. These were purely passive and intrinsically dead particles moving in the void. The cause of their motion was not explained, but was often associated with external forces which were assumed to be of spiritual origin and fundamentally different from matter. In subsequent centuries, this image became an essential element of Western thought, of the dualism between mind and matter, between body and soul.

As the idea of a division between spirit and matter took hold, the philosophers turned their attention to the spiritual world, rather than the material, to the human soul and the problems of ethics. These questions were to occupy Western thought for more than two thousand years after the culmination of Creek science and culture in the fifth and fourth centuries B.C. The scientific knowledge of antiquity was systematized and organized by Aristotle, who created the scheme which was to be the basis of the Western view of the universe for two thousand years. But Aristotle himself believed that questions concerning the human soul and the contemplation of God’s perfection were much more valuable than investigations of the material world. The reason the Aristotelian model of the universe remained unchallenged for so long was precisely this lack of interest in the material world, and the strong hold of the Christian Church which supported Aristotle’s doctrines throughout the Middle Ages.

Further development of Western science had to wait until the Renaissance, when men began to free themselves from the influence of Aristotle and the Church and showed a new interest in nature. In the late fifteenth century, the study of nature was approached, for the first time, in a truly scientific spirit and experiments were undertaken to test speculative ideas. As this development was paralleled by a growing interest in mathematics, it finally led to the formulation of proper scientific theories, based on experiment and expressed in mathematical language. Galileo was the first to combine empirical knowledge with mathematics and is therefore seen as the father of modern science.

The birth of modern science was preceded and accompanied by a development of philosophical thought which led to an extreme formulation of the spirit/matter dualism. This formulation appeared in the seventeenth century in the philosophy of René Descartes who based his view of nature on a fundamental division into two separate and independent realms; that of mind (res cogitans), and that of matter (res extensa). The ‘Cartesian’ division allowed scientists to treat matter as dead and completely separate from themselves, and to see the material world as a multitude of different objects assembled into a huge machine. Such a mechanistic world view was held by Isaac Newton who constructed his mechanics on its basis and made it the foundation of classical physics. From the second half of the seventeenth to the end of the nineteenth century, the mechanistic Newtonian model of the universe dominated all scientific thought. It was paralleled by the image of a monarchical God who ruled the world from above by imposing his divine law on it. The fundamental laws of nature searched for by the scientists were thus seen as the laws of God, invariable and eternal, to which the world was subjected.

The philosophy of Descartes was not only important for the development of classical physics, but also had a tremendous influence on the general Western way of thinking up to the present day. Descartes’ famous sentence ‘Cogito ergo sum’—‘I think, therefore I exist’—has led Westerners to equate their identity with their mind, instead of with their whole organism. As a consequence of the Cartesian division, most individuals are aware of themselves as isolated egos existing ‘inside’ their bodies. The mind has been separated from the body and given the futile task of controlling it, thus causing an apparent conflict between the conscious will and the involuntary instincts. Each individual has been split up further into a large number of separate compartments, according to his or her activities, talents, feelings, beliefs, etc., which are engaged in endless conflicts generating continuous metaphysical confusion and frustration.

This inner fragmentation mirrors our view of the world ‘outside’ which is seen as a multitude of separate objects and events. The natural environment is treated as if it consisted of separate parts to be exploited by different interest groups. The fragmented view is further extended to society which is split into different nations, races, religious and political groups. The belief that all these fragments—in ourselves, in our environment and in our society—are really separate can be seen as the essential reason for the present series of social, ecological and cultural crises. It has alienated us from nature and from our fellow human beings. It has brought a grossly unjust distribution of natural resources creating economic and political disorder; an ever rising wave of violence, both spontaneous and institutionalized, and an ugly, polluted environment in which life has often become physically and mentally unhealthy.

The Cartesian division and the mechanistic world view have thus been beneficial and detrimental at the same time. They were extremely successful in the development of classical physics and technology, but had many adverse consequences for our civilization. It is fascinating to see that twentieth-century science, which originated in the Cartesian split and in the mechanistic world view, and which indeed only became possible because of such a view, now overcomes this fragmentation and leads back to the idea of unity expressed in the early Greek and Eastern philosophies.

In contrast to the mechanistic Western view, the Eastern view of the world is ‘organic’. For the Eastern mystic, all things and events perceived by the senses are interrelated, connected, and are but different aspects or manifestations of the same ultimate reality. Our tendency to divide the perceived world into individual and separate things and to experience ourselves as isolated egos in this world is seen as an illusion which comes from our measuring and categorizing mentality. It is called avidya, or ignorance, in Buddhist philosophy and is seen as the state of a disturbed mind which has to be overcome:

When the mind is disturbed, the multiplicity of things is produced, but when the mind is quieted, the multiplicity of things disappears.⁴

Although the various schools of Eastern mysticism differ in many details, they all emphasize the basic unity of the universe which is the central feature of their teachings. The highest aim for their followers—whether they are Hindus, Buddhists or Taoists—is to become aware of the unity and mutual interrelation of all things, to transcend the notion of an isolated individual self and to identify themselves with the ultimate reality. The emergence of this awareness—known as ‘enlightenment’—is not only an intellectual act but is an experience which involves the whole person and is religious in its ultimate nature. For this reason, most Eastern philosophies are essentially religious philosophies.

In the Eastern view, then, the division of nature into separate objects is not fundamental and any such objects have a fluid and ever-changing character. The Eastern world view is therefore intrinsically dynamic and contains time and change as essential features. The cosmos is seen as one inseparable reality—for ever in motion, alive, organic; spiritual and material at the same time.

Since motion and change are essential properties of things, the forces causing the motion are not outside the objects, as in the classical Creek view, but are an intrinsic property of matter. Correspondingly, the Eastern image of the Divine is not that of a ruler who directs the world from above, but of a principle that controls everything from within:

He who, dwelling in all things,

Yet is other than all things,

Whom all things do not know,

Whose body all things are,

Who controls all things from within—

He is your Soul, the Inner Controller,

The Immortal.⁵

The following chapters will show that the basic elements of the Eastern world view are also those of the world view emerging from modern physics. They are intended to suggest that Eastern thought and, more generally, mystical thought provide a consistent and relevant philosophical background to the theories of contemporary science; a conception of the world in which scientific discoveries can be in perfect harmony with spiritual aims and religious beliefs. The two basic themes of this conception are the unity and interrelation of all phenomena and the intrinsically dynamic nature of the universe. The further we penetrate into the submicroscopic world, the more we shall realize how the modern physicist, like the Eastern mystic, has come to see the world as a system of inseparable, interacting and ever-moving components with the observer being an integral part of this system.

The organic, ‘ecological’ world view of the Eastern philosophies is no doubt one of the main reasons for the immense popularity they have recently gained in the West, especially among young people. In our Western culture, which is still dominated by the mechanistic, fragmented view of the world, an increasing number of people have seen this as the underlying reason for the widespread dissatisfaction in our society, and many have turned to Eastern ways of liberation. It is interesting, and perhaps not too surprising, that those who are attracted by Eastern mysticism, who consult the I Ching and practise Yoga or other forms of meditation, in general have a marked anti-scientific attitude. They tend to see science, and physics in particular, as an unimaginative, narrow-minded discipline which is responsible for all the evils of modern technology.

This book aims at improving the image of science by showing that there is an essential harmony between the spirit of Eastern wisdom and Western science. It attempts to suggest that modern physics goes far beyond technology, that the way—or Tao—of physics can be a path with a heart, a way to spiritual knowledge and self-realization.

Chapter 2 Knowing and Seeing

From the unreal lead me to the real!

From darkness lead me to light!

From death lead me to immortality!

Brihad-aranyaka Upanishad

Before studying the parallels between modern physics and Eastern mysticism, we have to deal with the question of how we can make any comparison at all between an exact science, expressed in the highly sophisticated language of modern mathematics, and spiritual disciplines which are mainly based on meditation and insist on the fact that their insights cannot be communicated verbally.

What we want to compare are the statements made by scientists and Eastern mystics about their knowledge of the world. To establish the proper framework for this comparison, we must firstly ask ourselves what kind of ‘knowledge’ we are talking about; does the Buddhist monk from Angkor Wat or Kyoto mean the same thing by ‘knowledge’ as the physicist from Oxford or Berkeley? Secondly, what kind of statements are we going to compare? What are we going to select from the experimental data, equations and theories on the one side, and from the religious scriptures, ancient myths, or philosophical treatises on the other? This chapter is intended to clarify these two points: the nature of the knowledge involved and the language in which this knowledge is expressed.

Throughout history, it has been recognized that the human mind is capable of two kinds of knowledge, or two modes of consciousness, which have often been termed the rational and the intuitive, and have traditionally been associated with science and religion, respectively. In the West, the intuitive, religious type of knowledge is often devalued in favour of rational, scientific knowledge, whereas the traditional Eastern attitude is in general just the opposite. The following statements about knowledge by two great minds of the West and the East typify the two positions. Socrates in Greece made the famous statement ‘I know that I know nothing’, and Lao Tzu in China said, ‘Not knowing that one knows is best’ In the East, the values attributed to the two kinds of knowledge are often already apparent from the names given to them. The Upanishads, for example, speak about a higher and a lower knowledge and associate the lower knowledge with various sciences, the higher with religious awareness. Buddhists talk about ‘relative’ and ‘absolute’ knowledge, or about ‘conditional truth’ and ‘transcendental truth’. Chinese philosophy, on the other hand, has always emphasized the complementary nature of the intuitive and the rational and has represented them by the archetypal pair yin and yang which form the basis of Chinese thought. Accordingly, two complementary philosophical traditions—Taoism and Confucianism—have developed in ancient China to deal with the two kinds of knowledge.

Rational knowledge is derived from the experience we have with objects and events in our everyday environment. It belongs to the realm of the intellect whose function it is to discriminate, divide, compare, measure and categorize. In this way, a world of intellectual distinctions is created; of opposites which can only exist in relation to each other, which is why Buddhists call this type of knowledge ‘relative’.

Abstraction is a crucial feature of this knowledge, because in order to compare and to classify the immense variety of shapes, structures and phenomena around us we cannot take all their features into account, but have to select a few significant ones. Thus we construct an intellectual map of reality in which things are reduced to their general outlines. Rational knowledge is thus a system of abstract concepts and symbols, characterized by the linear, sequential structure which is typical of our thinking and speaking. In most languages this linear structure is made explicit by the use of alphabets which serve to communicate experience and thought in long lines of letters.

The natural world, on the other hand, is one of infinite varieties and complexities, a multidimensional world which contains no straight lines or completely regular shapes, where things do not happen in sequences, but all together; a world where—as modern physics tells us—even empty space is curved. It is clear that our abstract system of conceptual thinking can never describe or understand this reality completely. In thinking about the world we are faced with the same kind of problem as the cartographer who tries to cover the curved face of the Earth with a sequence of plane maps. We can only expect an approximate representation of reality from such a procedure, and all rational knowledge is therefore necessarily limited.

The realm of rational knowledge is, of course, the realm of science which measures and quantifies, classifies and analyses. The limitations of any knowledge obtained by these methods have become increasingly apparent in modern science, and in particular in modern physics which has taught us, in the words of Werner Heisenberg, ‘that every word or concept, clear as it may seem to be, has only a limited range of applicability.’¹

For most of us it is very difficult to be constantly aware of the limitations and of the relativity of conceptual knowledge. Because our representation of reality is so much easier to grasp than reality itself, we tend to confuse the two and to take our concepts and symbols for reality. It is one of the main aims of Eastern mysticism to rid us of this confusion. Zen Buddhists say that a finger is needed to point at the moon, but that we should not trouble ourselves with the finger once the moon is recognized; the Taoist sage Chuang Tzu wrote:

Fishing baskets are employed to catch fish; but when the fish are got, the men forget the baskets; snares are employed to catch hares; but when the hares are got, men forget the snares. Words are employed to convey ideas; but when the ideas are grasped, men forget the words.²

In the West, the semanticist Alfred Korzybski made exactly the same point with his powerful slogan, The map is not the territory.’

What the Eastern mystics are concerned with is a direct experience of reality which transcends not only intellectual thinking but also sensory perception. In the words of the Upanishads,

What is soundless, touchless, formless, imperishable,

Likewise tasteless, constant, odourless,

Without beginning, without end, higher than the great, stable—

By discerning That, one is liberated from the mouth of death.³

Knowledge which comes from such an experience is called ‘absolute knowledge’ by Buddhists because it does not rely on the discriminations, abstractions and classifications of the intellect which, as we have seen, are always relative and approximate. It is, so we are told by Buddhists, the direct experience of undifferentiated, undivided, indeterminate ‘suchness’. Complete apprehension of this suchness is not only the core of Eastern mysticism, but is the central characteristic of all mystical experience.

The Eastern mystics repeatedly insist on the fact that the ultimate reality can never be an object of reasoning or of demonstrable knowledge. It can never be adequately described by words, because it lies beyond the realms of the senses and of the intellect from which our words and concepts are derived. The Upanishads say about it:

There the eye goes not,

Speech goes not, nor the mind.

We know not, we understand not

How one would teach it.⁴

Lao Tzu, who calls this reality the Tao, states the same fact in the opening line of the Tao Te Ching: The Tao that can be expressed is not the eternal Tao.’ The fact—obvious from any reading of the newspapers—that humanity has not become much wiser over the past two thousand years, in spite of a prodigious increase in rational knowledge, is ample evidence of the impossibility of communicating absolute knowledge by words. As Chuang Tzu said, ‘If it could be talked about, everybody would have told their brother.’⁵

Absolute knowledge is thus an entirely non-intellectual experience of reality, an experience arising in a non-ordinary state of consciousness which may be called a ‘meditative’ or mystical state. That such a state exists has not only been testified by numerous mystics in the East and West but is also indicated by psychological research. In the words of William James:

Our normal waking consciousness, rational consciousness as we call it, is but one special type of consciousness, whilst all about it, parted from it by the filmiest of screens, there lie potential forms of consciousness entirely different.⁶

Although physicists are mainly concerned with rational knowledge and mystics with intuitive knowledge, both types of knowledge occur in both fields. This becomes apparent when we examine how knowledge is obtained and how it is expressed, both in physics and Eastern mysticism.

In physics, knowledge is acquired through the process of scientific research which can be seen to proceed in three stages. The first stage consists in gathering experimental evidence about the phenomena to be explained. In the second stage, the experimental facts are correlated with mathematical symbols and a mathematical scheme is worked out which interconnects these symbols in a precise and consistent way. Such a scheme is usually called a mathematical model or, if it is more comprehensive, a theory. This theory is then used to predict the results of further experiments which are undertaken to check all its implications. At this stage, physicists may be satisfied when they have found a mathematical scheme and know how to use it to predict experiments. But eventually, they will want to talk about their results to non-physicists and will therefore have to express them in plain language. This means they will have to formulate a model in ordinary language which interprets their mathematical scheme. Even for the physicists themselves, the formulation of such a verbal model, which constitutes the third stage of research, will be a criterion of the understanding they have reached.

In practice, of course, the three stages are not neatly separated and do not always occur in the same order. For example, a physicist may be led to a particular model by some philosophical belief he (or she) holds, which he may continue to believe in, even when contrary experimental evidence arises. He will then—and this happens in fact very often—try to modify his model so that it can account for the new experiments. But if experimental evidence continues to contradict the model he will eventually be forced to drop it.

This way of basing all theories firmly on experiment is known as the scientific method and we shall see that it has its counterpart in Eastern philosophy. Creek philosophy, on the other hand, was fundamentally different in that respect. Although Creek philosophers had extremely ingenious ideas about nature which often come very close to modern scientific models, the enormous difference between the two is the empirical attitude of modern science which was by and large foreign to the Creek mind. The Greeks obtained their models deductively from some fundamental axiom or principle and not inductively from what had been observed. On the other hand, of course, the Creek art of deductive reasoning and logic is an essential ingredient in the second stage of scientific research, the formulation of a consistent mathematical model, and thus an essential part of science.

Rational knowledge and rational activities certainly constitute the major part of scientific research, but are not all there is to it. The rational part of research would, in fact, be useless if it were not complemented by the intuition that gives scientists new insights and makes them creative. These insights tend to come suddenly and, characteristically, not when sitting at a desk working out the equations, but when relaxing, in the bath, during a walk in the woods, on the beach, etc. During these periods of relaxation after concentrated intellectual activity, the intuitive mind seems to take over and can produce the sudden clarifying insights which give so much joy and delight to scientific research.

Intuitive insights, however, are of no use to physics unless they can be formulated in a consistent mathematical framework, supplemented by an interpretation in plain language. Abstraction is a crucial feature of this framework. It consists, as mentioned before, of a system of concepts and symbols which constitute a map of reality. This map represents only some features of reality; we do not know exactly which these are, since we started compiling our map gradually and without critical analysis in our childhood. The words of our language are thus not clearly defined. They have several meanings, many of which pass only vaguely through our mind and remain largely in our subconscious when we hear a word.

The inaccuracy and ambiguity of our language is essential for poets who work largely with its subconscious layers and associations. Science, on the other hand, aims for clear definitions and unambiguous connections, and therefore it abstracts language further by limiting the meaning of its words and by standardizing its structure, in accordance with the rules of logic. The ultimate abstraction takes place in mathematics where words are replaced by symbols and where the operations of connecting the symbols are rigorously defined. In this way, scientists can condense information into one equation, i.e. into one single line of symbols, for which they would need several pages of ordinary writing.

The view that mathematics is nothing but an extremely abstracted and compressed language does not go unchallenged. Many mathematicians, in fact, believe that mathematics is not just a language to describe nature, but is inherent in nature itself. The originator of this belief was Pythagoras who made the famous statement ‘All things are numbers’ and developed a very special kind of mathematical mysticism. Pythagorean philosophy thus introduced logical reasoning into the domain of religion, a development which, according to Bertrand Russell, was decisive for Western religious philosophy:

The combination of mathematics and theology, which began with Pythagoras, characterized religious philosophy in Greece, in the Middle Ages, and in modern times down to Kant … In Plato, St Augustine, Thomas Aquinas, Descartes, Spinoza and Leibniz there is an intimate blending of religion and reasoning, of moral aspiration with logical admiration of what is timeless, which comes from Pythagoras, and distinguishes the intellectualized theology of Europe from the more straightforward mysticism of Asia.⁷

The ‘more straightforward mysticism of Asia’ would, of course, not adopt the Pythagorean view of mathematics. In the Eastern view, mathematics, with its highly differentiated and well defined structure, must be seen as part of our conceptual map and not as a feature of reality itself. Reality, as experienced by the mystic, is completely indeterminate and undifferentiated.

The scientific method of abstraction is very efficient and powerful, but we have to pay a price for it. As we define our system of concepts more precisely, as we streamline it and make the connections more and more rigorous, it becomes increasingly detached from the real world. Using again Korzybski’s analogy of the map and the territory, we could say that ordinary language is a map which, due to its intrinsic inaccuracy, has a certain flexibility so that it can follow the curved shape of the territory to some degree. As we make it more rigorous, this flexibility gradually disappears, and with the language of mathematics we have reached a point where the links with reality are so tenuous that the relation of the symbols to our sensory experience is no longer evident. This is why we have to supplement our mathematical models and theories with verbal interpretations, again using concepts which can be understood intuitively, but which are slightly ambiguous and inaccurate.

It is important to realize the difference between the mathematical models and their verbal counterparts. The former are rigorous and consistent as far as their internal structure is concerned, but their symbols are not directly related to our experience. The verbal models, on the other hand, use concepts which can be understood intuitively, but are always inaccurate and ambiguous. They are in this respect not different from philosophical models of reality and thus the two can very well be compared.

If there is an intuitive element in science, there is also a rational element in Eastern mysticism. The degree to which reason and logic are emphasized, however, varies enormously from one school to the other. The Hindu Vedanta, or the Buddhist Madhyamika, for example, are highly intellectual schools, whereas Taoists have always had a deep mistrust of reason and logic. Zen, which grew out of Buddhism but was strongly influenced by Taoism, prides itself on being ‘without words, without explanations, without instructions, without knowledge’. It concentrates almost entirely on the experience of enlightenment and is only marginally interested in interpreting this experience. A well known Zen phrase says The instant you speak about a thing you miss the mark.’

Although other schools of Eastern mysticism are less extreme, the direct mystical experience is at the core of all of them. Even those mystics who are engaged in the most sophisticated argumentation never see the intellect as their source of knowledge but use it merely to analyse and interpret their personal mystical experience. All knowledge is firmly based on this experience, thus giving the Eastern traditions a strong empirical character that is always emphasized by its proponents. D. T. Suzuki, for example, writes of Buddhism:

Personal experience is … the foundation of Buddhist philosophy. In this sense Buddhism is radical empiricism or experientialism, whatever dialectic later developed to probe the meaning of enlightenment-experience.⁸

Joseph Needham repeatedly brings the empirical attitude of Taoists into prominence in his work Science and Civilisation in China and finds that this attitude has made Taoism the basis of Chinese science and technology. The early Taoist philosophers, in Needham’s words, ‘withdrew into the wilderness, the forests and mountains, there to meditate upon the Order of Nature, and to observe its innumerable manifestations’.⁹ The same spirit is reflected in the Zen verses,

He who would understand the meaning of Buddha-nature Must watch for the season and the causal relations.¹⁰

The firm basis of knowledge on experience in Eastern mysticism suggests a parallel to the firm basis of scientific knowledge on experiment. This parallel is further enforced by the nature of the mystical experience. It is described in the Eastern traditions as a direct insight which lies outside the realm of the intellect and is obtained by watching rather than thinking; by looking inside oneself; by observation.

In Taoism, this notion of observation is embodied in the name for Taoist temples, kuan, which originally meant ‘to look’. Taoists thus regarded their temples as places of observation. In Ch’an Buddhism, the Chinese version of Zen, enlightenment is often referred to as ‘the vision of the Tao’, and seeing is regarded as the basis of knowing in all Buddhist schools. The first item of the Eightfold Path, the Buddha’s prescription for self-realization, is right seeing followed by right knowing. D. T. Suzuki writes on this point:

The seeing plays the most important role in Buddhist epistemology, for seeing is at the basis of knowing. Knowing is impossible without seeing; all knowledge has its origin in seeing. Knowing and seeing are thus found generally united in Buddha’s teaching. Buddhist philosophy therefore ultimately points to seeing reality as it is. Seeing is experiencing enlightenment.¹¹

This passage is also reminiscent of the Yaqui mystic Don Juan who says, ‘My predilection is to see … because only by seeing can a man of knowledge know.’¹²

A word of caution should perhaps be added here. The emphasis on seeing in mystical traditions should not be taken too literally, but has to be understood in a metaphorical sense, since the mystical experience of reality is an essentially non-sensory experience. When the Eastern mystics talk about ‘seeing’, they refer to a mode of perception which may include visual perception, but which always and essentially transcends it to become a nonsensory experience of reality. What they do emphasize, however, when they talk about seeing, looking or observing is the empirical character of their knowledge. This empirical approach of Eastern philosophy is strongly reminiscent of the emphasis on observation in science and thus suggests a framework for our comparison. The experimental stage in scientific research seems to correspond to the direct insight of the Eastern mystic, and the scientific models and theories correspond to the various ways in which this insight is interpreted.

The parallel between scientific experiments and mystical experiences may seem surprising in view of the very different nature of these acts of observation. Physicists perform experiments involving an elaborate teamwork and a highly sophisticated technology, whereas mystics obtain their knowledge purely through introspection, without any machinery, in the privacy of meditation. Scientific experiments, furthermore, seem to be repeatable any time and by anybody, whereas mystical experiences seem to be reserved for a few individuals at special occasions. A closer examination shows, however, that the differences between the two kinds of observation lie only in their approach and not in their reliability or complexity.

Anybody who wants to repeat an experiment in modern subatomic physics has to undergo many years of training. Only then will he or she be able to ask nature a specific question through the experiment and to understand the answer. Similarly, a deep mystical experience requires, generally, many years of training under an experienced master and, as in the scientific training, the dedicated time does not alone guarantee success. If the student is successful, however, he or she will be able to ‘repeat the experiment’. The repeatability of the experience is, in fact, essential to every mystical training and is the very aim of the mystics’ spiritual instruction.

A mystical experience, therefore, is not any more unique than a modern experiment in physics. On the other hand, it is not less sophisticated either, although its sophistication is of a very different kind. The complexity and efficiency of the physicist’s technical apparatus is matched, if not surpassed, by that of the mystic’s consciousness—both physical and spiritual—in deep meditation. The scientists and the mystics, then, have developed highly sophisticated methods of observing nature which are inaccessible to the layperson. A page from a journal of modern experimental physics will be as mysterious to the uninitiated as a Tibetan mandala. Both are records of enquiries into the nature of the universe.

Although deep mystical experiences do not, in general, occur without long preparation, direct intuitive insights are experienced by all of us in our everyday lives. We are all familiar with the situation where we have forgotten the name of a person or place, or some other word, and cannot produce it in spite of the utmost concentration. We have it ‘on the tip of our tongue’ but it just will not come out, until we give up and shift our attention to something else when suddenly, in a flash, we remember the forgotten name. No thinking is involved in this process. It is a sudden, immediate insight. This example of suddenly remembering something is particularly relevant to Buddhism which holds that our original nature is that of the enlightened Buddha and that we have just forgotten it. Students of Zen Buddhism are asked to discover their ‘original face’ and the sudden ‘remembering’ of this face is their enlightenment.

Another well known example of spontaneous intuitive insights are jokes. In the split second where you understand a joke you experience a moment of ‘enlightenment’. It is well known that this moment must come spontaneously, that it cannot be achieved by ‘explaining’ the joke, i.e. by intellectual analysis. Only with a sudden intuitive insight into the nature of the joke do we experience the liberating laughter the joke is meant to produce. The similarity between a spiritual insight and the understanding of a joke must be well known to enlightened men and women, since they almost invariably show a great sense of humour. Zen, especially, is full of funny stories and anecdotes, and in the Tao Te Ching we read, ‘If it were not laughed at, it would not be sufficient to be Tao.’¹³

In our everyday life, direct intuitive insights into the nature of things are normally limited to extremely brief moments. Not so in Eastern mysticism where they are extended to long periods and, ultimately, become a constant awareness. The preparation of the mind for this awareness—for the immediate, nonconceptual awareness of reality—is the main purpose of all schools of Eastern mysticism, and of many aspects of the Eastern way of life. During the long cultural history of India, China and Japan, an enormous variety of techniques, rituals and art forms have been developed to achieve this purpose, all of which may be called meditation in the widest sense of the word.

The basic aim of these techniques seems to be to silence the thinking mind and to shift the awareness from the rational to the intuitive mode of consciousness. In many forms of meditation, this silencing of the rational mind is achieved by concentrating one’s attention on a single item, like one’s breathing, the sound of a mantra, or the visual image of a mandala. Other schools focus the attention on body movements which have to be performed spontaneously without the interference of any thought. This is the way of the Hindu Yoga and of the Taoist Tai Chi Ch’uan. The rhythmical movements of these schools can lead to the same feeling of peace and serenity which is characteristic of the more static forms of meditation; a feeling which, incidentally, may be evoked also by some sports. In my experience, for example, skiing has been a highly rewarding form of meditation.

Eastern art forms, too, are forms of meditation. They are not so much means for expressing the artist’s ideas as ways of self-realization through the development of the intuitive mode of consciousness. Indian music is not learned by reading notes, but by listening to the play of the teacher and thus developing a feeling for the music, just as the T’ai Chi movements are not learned by verbal instructions but by doing them over and over again in unison with the teacher. Japanese tea ceremonies are full of slow, ritualistic movements. Chinese calligraphy requires the uninhibited, spontaneous movement of the hand. All these skills are used in the East to develop the meditative mode of consciousness.

For most people, and especially for intellectuals, this mode of consciousness is a completely new experience. Scientists are familiar with direct intuitive insights from their research, because every new discovery originates in such a sudden non-verbal flash. But these are extremely short moments which arise when the mind is filled with information, with concepts and thought patterns. In meditation, on the other hand, the mind is emptied of all thoughts and concepts and thus prepared to function for long periods through its intuitive mode. Lao Tzu speaks about this contrast between research and meditation when he says:

He who pursues learning will increase every day;

He who pursues Tao will decrease every day.¹⁴

When the rational mind is silenced, the intuitive mode produces an extraordinary awareness; the environment is experienced in a direct way without the filter of conceptual thinking. In the words of Chuang Tzu, The still mind of the sage is a mirror of heaven and earth—the glass of all things.’¹⁵ The experience of oneness with the surrounding environment is the main characteristic of this meditative state. It is a state of consciousness where every form of fragmentation has ceased, fading away into undifferentiated unity.

In deep meditation, the mind is completely alert. In addition to the nonsensory apprehension of reality it also takes in all the sounds, sights, and other impressions of the surrounding environment, but it does not hold the sensory images to be analysed or interpreted. They are not allowed to distract the attention. Such a state of awareness is not unlike the state of mind of a warrior who expects an attack in extreme alertness, registering everything that goes on around him without being distracted by it for an instant. The Zen master Yasutani Roshi uses this image in his description of shikan-taza, the practice of Zen meditation:

Shikan-taza is a heightened state of concentrated awareness wherein one is neither tense nor hurried, and certainly never slack. It is the mind of somebody facing death. Let us imagine that you are engaged in a duel of swordsmanship of the kind that used to take place in ancient Japan. As you face your opponent you are unceasingly watchful, set, ready. Were you to relax your vigilance even momentarily, you would be cut down instantly. A crowd gathers to see the fight. Since you are not blind you see them from the corner of your eye, and since you are not deaf you hear them. But not for an instant is your mind captured by these sense impressions.¹⁶

Because of the similarity between the meditative state and the frame of mind of a warrior, the image of the warrior plays an important role in the spiritual and cultural life of the East. The stage for India’s favourite religious text, the Bhagavad Gita, is a battlefield and martial arts constitute an important part in the traditional cultures of China and Japan. In Japan, the strong influence of Zen on the tradition of the samurai gave rise to what is known as bushido, ‘the way of the warrior’, an art of swordsmanship where the spiritual insight of the swordsman reaches its highest perfection. The Taoist Tai Chi Ch’uan, which was considered to be the supreme martial art in China, combines slow and rhythmical ‘yogic’ movements with the total alertness of the warrior’s mind in a unique way.

Eastern mysticism is based on direct insights into the nature of reality, and physics is based on the observation of natural phenomena in scientific experiments. In both fields, the observations are then interpreted and the interpretation is very often communicated by words. Since words are always an abstract, approximate map of reality, the verbal interpretations of a scientific experiment or of a mystical insight are necessarily inaccurate and incomplete. Modern physicists and Eastern mystics alike are well aware of this fact.

In physics, the interpretations of experiments are called models or theories and the realization that all models and theories are approximate is basic to modern scientific research. Thus the aphorism of Einstein, ‘As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.’ Physicists know that their methods of analysis and logical reasoning can never explain the whole realm of natural phenomena at once and so they single out a certain group of phenomena and try to build a model to describe this group. In doing so, they neglect other phenomena and the model will therefore not give a complete description of the real situation. The phenomena which are not taken into account may either have such a small effect that their inclusion would not alter the theory significantly, or they may be left out simply because they are not known at the time when the theory is built.

To illustrate these points, let us look at one of the best known models in physics, Newton’s ‘classical’ mechanics. The effects of air resistance or friction, for example, are generally not taken into account in this model, because they are usually very small. But apart from such omissions, Newtonian mechanics was for a long time considered to be the final theory for the description of all natural phenomena, until electric and magnetic phenomena, which had no place in Newton’s theory, were discovered. The discovery of these phenomena showed that the model was incomplete, that it could be applied only to a limited group of phenomena, essentially the motion of solid bodies.

Studying a limited group of phenomena can also mean studying their physical properties only over a limited range, which may be another reason for the theory to be approximate. This aspect of the approximation is quite subtle because we never know beforehand where the limitations of a theory lie. Only experience can tell. Thus the image of classical mechanics was further eroded when twentieth-century physics showed its essential limitations. Today we know that the Newtonian model is valid only for objects consisting of large numbers of atoms, and only for velocities which are small compared to the speed of light. When the first condition is not given, classical mechanics has to be replaced by quantum theory; when the second condition is not satisfied, relativity theory has to be applied. This does not mean that Newton’s model is ‘wrong’, or that quantum theory and relativity theory are ‘right’. All these models are approximations which are valid for a certain range of phenomena. Beyond this range, they no longer give a satisfactory description of nature and new models have to be found to replace the old ones—or, better, to extend them by improving the approximation.

To specify the limitations of a given model is often one of the most difficult, and yet one of the most important tasks in its construction. According to Geoffrey Chew, whose ‘bootstrap theory’ will be discussed at great length later on, it is essential that one should always ask, as soon as a certain model or theory is found to work: why does it work? what are the model’s limits? in what way, exactly, is it an approximation? These questions are seen by Chew as the first step towards further progress.

The Eastern mystics, too, are well aware of the fact that all verbal descriptions of reality are inaccurate and incomplete. The direct experience of reality transcends the realm of thought and language, and, since all mysticism is based on such a direct experience, everything that is said about it can only be partly true. In physics, the approximate nature of all statements is quantified and progress is made by improving the approximations in many successive steps. How, then, do the Eastern traditions deal with the problem of verbal communication?

First of all, mystics are mainly interested in the experience of reality and not in the description of this experience. They are therefore generally not interested in the analysis of such a description, and the concept of a well-defined approximation has thus never arisen in Eastern thought. If, on the other hand, Eastern mystics want to communicate their experience, they are confronted with the limitations of language. Several different ways have been developed in the East to deal with this problem.

Indian mysticism, and Hinduism in particular, clothes its statements in the form of myths, using metaphors and symbols, poetic images, similes and allegories. Mythical language is much less restricted by logic and common sense. It is full of magic and of paradoxical situations, rich in suggestive images and never precise, and can thus convey the way in which mystics experience reality much better than factual language. According to Ananda Coomaraswamy, ‘myth embodies the nearest approach to absolute truth that can be stated in words.’¹⁷

The rich Indian imagination has created a vast number of gods and goddesses whose incarnations and exploits are the subjects of fantastic tales, collected in epics of huge dimensions. The Hindu with deep insight knows that all these gods are creations of the mind, mythical images representing the many faces of reality. On the other hand, he or she also knows that they were not merely created to make the stories more attractive, but are essential vehicles to convey the doctrines of a philosophy rooted in mystical experience.

Chinese and Japanese mystics have found a different way of dealing with the language problem. Instead of making the paradoxical nature of reality palatable through the symbols and images of myth, they prefer very often to accentuate it by using factual language. Thus Taoists made frequent use of paradoxes in order to expose the inconsistencies arising from verbal communication and to show its limits. They have passed this technique on to Chinese and Japanese Buddhists who have developed it further. It has reached its extreme in Zen Buddhism with the so-called koans, those nonsensical riddles which are used by many Zen masters to transmit the teachings. These koans establish an important parallel to modern physics which will be taken up in the next chapter.

In Japan, there exists yet another mode of expressing philosophical views which should be mentioned. It is a special form of extremely concise poetry which is often used by Zen masters to point directly at the ‘suchness’ of reality. When a monk asked Fuketsu Ensho, When speech and silence are both inadmissible, how can one pass without error?’ the master replied:

I always remember Kiangsu in March—

The cry of the partridge,

The mass of fragrant flowers.¹⁸

This form of spiritual poetry has reached its perfection in the haiku, a classical Japanese verse of just seventeen syllables, which was deeply influenced by Zen. The insight into the very nature of Life reached by these haiku poets comes across even in the English translation:

Leaves falling

Lie on one another;

The rain beats the rain.¹⁹

Whenever the Eastern mystics express their knowledge in words—be it with the help of myths, symbols, poetic images or paradoxical statements—they are well aware of the limitations imposed by language and ‘linear’ thinking. Modern physics has come to take exactly the same attitude with regard to its verbal models and theories. They, too, are only approximate and necessarily inaccurate. They are the counterparts of the Eastern myths, symbols and poetic images, and it is at this level that I shall draw the parallels. The same idea about matter is conveyed, for example, to the Hindu by the cosmic dance of the god Shiva as to the physicist by certain aspects of quantum field theory. Both the dancing god and the physical theory are creations of the mind: models to describe their authors’ intuition of reality.

Chapter 3 Beyond Language

The contradiction so puzzling to the ordinary way of thinking comes from the fact that we have to use language to communicate our inner experience which in its very nature transcends linguistics.

D. T. Suzuki

The problems of language here are really serious. We wish to speak in some way about the structure of the atoms … But we cannot speak about atoms in ordinary language.

W. Heisenberg

The notion that all scientific models and theories are approximate and that their verbal interpretations always suffer from the inaccuracy of our language was already commonly accepted by scientists at the beginning of this century, when a new and completely unexpected development took place. The study of the world of atoms forced physicists to realize that our common language is not only inaccurate, but totally inadequate to describe the atomic and subatomic reality. Quantum theory and relativity theory, the two bases of modern physics, have made it clear that this reality transcends classical logic and that we cannot talk about it in ordinary language. Thus Heisenberg writes:

The most difficult problem … concerning the use of the language arises in quantum theory. Here we have at first no simple guide for correlating the mathematical symbols with concepts of ordinary language; and the only thing we know from the start is the fact that our common concepts cannot be applied to the structure of the atoms.¹

From a philosophical point of view, this has certainly been the most interesting development in modern physics, and here lies one of the roots of its relation to Eastern philosophy. In the schools of Western philosophy, logic and reasoning have always been the main tools used to formulate philosophical ideas and this is true, according to Bertrand Russell, even of religious philosophies. In Eastern mysticism, on the other hand, it has always been realized that reality transcends ordinary language, and the sages of the East were not afraid to go beyond logic and common concepts. This is the main reason, I think, why their models of reality constitute a more appropriate philosophical background to modern physics than the models of Western philosophy.

The problem of language encountered by the Eastern mystic is exactly the same as the problem the modern physicist faces. In the two passages quoted at the beginning of this chapter, D. T. Suzuki speaks about Buddhism² and Werner Heisenberg speaks about atomic physics,³ and yet the two passages are almost identical. Both the physicist and the mystic want to communicate their knowledge, and when they do so with words their statements are paradoxical and full of logical contradictions. These paradoxes are characteristic of all mysticism, from Heraclitus to Don Juan, and since the beginning of this century they are also characteristic of physics.

In atomic physics, many of the paradoxical situations are connected with the dual nature of light or—more generally—of electromagnetic radiation. On the one hand, it is clear that this radiation must consist of waves because it produces the well-known interference phenomena associated with waves: when there are two sources of light, the intensity of the light to be found at some other place will not necessarily be just the sum of that which comes from the two sources, but may be more or less. This can easily be explained by the interference of the waves emanating from the two sources: in those places where two crests coincide we shall have more light than the sum of the two; where a crest and a trough coincide we shall have less. The precise amount of interference can easily be calculated. Interference phenomena of this kind can be observed whenever one deals with electromagnetic radiation, and force us to conclude that this radiation consists of waves.

On the other hand, electromagnetic radiation also produces the so-called photoelectric effect: when ultraviolet light is shone on the surface of some metals it can ‘kick out’ electrons from the surface of the metal, and therefore it must consist of moving particles. A similar situation occurs in the ‘scattering’ experiments of X-rays. These experiments can only be interpreted correctly if they are described as collisions of ‘light particles’ with electrons. And yet, they show the interference patterns characteristic of waves. The question which puzzled physicists so much in the early stages of atomic theory was how electromagnetic radiation could simultaneously consist of particles (i.e. of entities confined to a very small volume) and of waves, which are spread out over a large area of space. Neither language nor imagination could deal with this kind of reality very well.

Eastern mysticism has developed several different ways of dealing with the paradoxical aspects of reality. Whereas they are bypassed in Hinduism through the use of mythical language, Buddhism and Taoism tend to emphasize the paradoxes rather than conceal them. The main Taoist scripture, Lao Tzu’s Tao Te Ching, is written in an extremely puzzling, seemingly illogical style. It is full of intriguing contradictions and its compact, powerful, and extremely poetic language is meant to arrest the reader’s mind and throw it off its familiar tracks of logical reasoning.

Chinese and Japanese Buddhists have adopted this Taoist technique of communicating the mystical experience by simply exposing its paradoxical character. When the Zen master Daito saw the Emperor Godaigo, who was a student of Zen, the master said:

We were parted many thousands of kalpas ago, yet we have not been separated even for a moment. We are facing each other all day long, yet we have never met.⁴

Zen Buddhists have a particular knack for making a virtue out of the inconsistencies arising from verbal communication, and with the koan system they have developed a unique way of transmitting their teachings completely non-verbally. Koans are carefully devised nonsensical riddles which are meant to make the student of Zen realize the limitations of logic and reasoning in the most dramatic way. The irrational wording and paradoxical content of these riddles makes it impossible to solve them by thinking. They are designed precisely to stop the thought process and thus to make the student ready for the non-verbal experience of reality. The contemporary Zen master Yasutani introduced a Western student to one of the most famous koans with the following words:

One of the best koans, because the simplest, is Mu. This is its background: A monk came to Joshu, a renowned Zen master in China hundreds of years ago, and asked: ‘Has a dog Buddha-nature or not?’ Joshu retorted, ‘Mu!’ Literally, the expression means ‘no’ or ‘not’, but the significance of Joshu’s answer does not lie in this. Mo is the expression of the living, functioning, dynamic Buddha-nature. What you must do is discover the spirit or essence of this Mu, not through intellectual analysis but by search into your innermost being. Then you must demonstrate before me, concretely and vividly, that you understand Mu as living truth, without recourse to conceptions, theories, or abstract explanations. Remember, you can’t understand Mu through ordinary cognition, you must grasp it directly with your whole being.⁵

To a beginner, the Zen master will normally present either this Mu-koan or one of the following two:

‘What was your original face—the one you had before your parents gave birth to you?’

‘You can make the sound of two hands clapping. Now what is the sound of one hand?’

All these koans have more or less unique solutions which a competent master recognizes immediately. Once the solution is found, the koan ceases to be paradoxical and becomes a profoundly meaningful statement made from the state of consciousness which it has helped to awaken.

In the Rinzai school, the student has to solve a long series of koans, each of them dealing with a particular aspect of Zen. This is the only way this school transmits its teachings. It does not use any positive statements, but leaves it entirely to the student to grasp the truth through the koans.

Here we find a striking parallel to the paradoxical situations which confronted physicists at the beginning of atomic physics. As in Zen, the truth was hidden in paradoxes that could not be solved by logical reasoning, but had to be understood in the terms of a new awareness; the awareness of the atomic reality. The teacher here was, of course, nature, who, like the Zen masters, does not provide any statements. She just provides the riddles.

The solving of a koan demands a supreme effort of concentration and involvement from the student. In books about Zen we read that the koan grips the student’s heart and mind and creates a true mental impasse, a state of sustained tension in which the whole world becomes an enormous mass of doubt and questioning. The founders of quantum theory experienced exactly the same situation, described here most vividly by Heisenberg:

I remember discussions with Bohr which went through many hours till very late at night and ended almost in despair; and when at the end of the discussion I went alone for a walk in the neighbouring park I repeated to myself again and again the question: Can nature possibly be so absurd as it seemed to us in these atomic experiments?⁶

Whenever the essential nature of things is analysed by the intellect, it must seem absurd or paradoxical. This has always been recognized by the mystics, but has become a problem in science only very recently. For centuries, scientists were searching for the ‘fundamental laws of nature’ underlying the great variety of natural phenomena. These phenomena belonged to the scientists’ macroscopic environment and thus to the realm of their sensory experience. Since the images and intellectual concepts of their language were abstracted from this very experience, they were sufficient and adequate to describe the natural phenomena.

Questions about the essential nature of things were answered in classical physics by the Newtonian mechanistic model of the universe which, much in the same way as the Democritean model in ancient Greece, reduced all phenomena to the motions and interactions of hard indestructible atoms. The properties of these atoms were abstracted from the macroscopic notion of billiard balls, and thus from sensory experience. Whether this notion could actually be applied to the world of atoms was not questioned. Indeed, it could not be investigated experimentally.

In the twentieth century, however, physicists were able to tackle the question about the ultimate nature of matter experimentally. With the help of a most sophisticated technology they were able to probe deeper and deeper into nature, uncovering one layer of matter after the other in search for its ultimate ‘building blocks’. Thus the existence of atoms was verified, then their constituents were discovered—the nuclei and electrons—and finally the components of the nucleus—the protons and neutrons—and many other subatomic particles.

The delicate and complicated instruments of modern experimental physics penetrate deep into the submicroscopic world, into realms of nature far removed from our macroscopic environment, and make this world accessible to our senses. However, they can do so only through a chain of processes ending, for example, in the audible click of a Geiger counter, or in a dark spot on a photographic plate. What we see, or hear, are never the investigated phenomena themselves but always their consequences. The atomic and subatomic world itself lies beyond our sensory perception.

It is, then, with the help of modern instrumentation that we are able to ‘observe’ the properties of atoms and their constituents in an indirect way, and thus to ‘experience’ the subatomic world to some extent. This experience, however, is not an ordinary one, comparable to that of our daily environment. The knowledge about matter at this level is no longer derived from direct sensory experience, and therefore our ordinary language, which takes its images from the world of the senses, is no longer adequate to describe the observed phenomena. As we penetrate deeper and deeper into nature, we have to abandon more and more of the images and concepts of ordinary language.

On this journey to the world of the infinitely small, the most important step, from a philosophical point of view, was the first one: the step into the world of atoms. Probing inside the atom and investigating its structure, science transcended the limits of our sensory imagination. From this point on, it could no longer rely with absolute certainty on logic and common sense. Atomic physics provided the scientists with the first glimpses of the essential nature of things. Like the mystics, physicists were now dealing with a nonsensory experience of reality and, like the mystics, they had to face the paradoxical aspects of this experience. From then on therefore, the models and images of modern physics became akin to those of Eastern philosophy.

Chapter 4 The New Physics

According to the Eastern mystics, the direct mystical experience of reality is a momentous event which shakes the very foundations of one’s world view. D. T. Suzuki has called it ‘the most startling event that could ever happen in the realm of human consciousness … upsetting every form of standardised experience’,¹ and he has illustrated the shocking character of this experience with the words of a Zen master who described it as ‘the bottom of a pail breaking through’.

Physicists, at the beginning of this century, felt much the same way when the foundations of their world view were shaken by the new experience of the atomic reality, and they described this experience in terms which were often very similar to those used by Suzuki’s Zen master. Thus Heisenberg wrote:

The violent reaction on the recent development of modern physics can only be understood when one realises that here the foundations of physics have started moving; and that this motion has caused the feeling that the ground would be cut from science.²

Einstein experienced the same shock when he first came in contact with the new reality of atomic physics. He wrote in his autobiography:

All my attempts to adapt the theoretical foundation of physics to this (new type of) knowledge failed completely. It was as if the ground had been pulled out from under one, with no firm foundation to be seen anywhere, upon which one could have built.³

The discoveries of modern physics necessitated profound changes of concepts like space, time, matter, object, cause and effect, etc., and since these concepts are so basic to our way of experiencing the world it is not surprising that the physicists who were forced to change them felt something of a shock. Out of these changes emerged a new and radically different world view, still in the process of formation by current scientific research.

It seems, then, that Eastern mystics and Western physicists went through similar revolutionary experiences which led them to completely new ways of seeing the world. In the following two passages, the European physicist Niels Bohr and the Indian mystic Sri Aurobindo both express the depth and the radical character of this experience.

The great extension of our experience in recent years has brought to light the insufficiency of our simple mechanical conceptions and, as a consequence, has shaken the foundation on which the customary interpretation of observation was based.⁴

Niels Bohr

All things in fact begin to change their nature and appearance; one’s whole experience of the world is radically different … There is a new vast and deep way of experiencing seeing knowing contacting things.⁵

Sri Aurobindo

This chapter will serve to sketch a preliminary picture of this new conception of the world against the contrasting background of classical physics;* showing how the classical mechanistic world view had to be abandoned at the beginning of this century when quantum theory and relativity theory—the two basic theories of modern physics—forced us to adopt a much more subtle, holistic and ‘organic’ view of nature.

CLASSICAL PHYSICS

The world view which was changed by the discoveries of modern physics had been based on Newton’s mechanical model of the universe. This model constituted the solid framework of classical physics. It was indeed a most formidable foundation supporting, like a mighty rock, all of science and providing a firm basis for natural philosophy for almost three centuries.

The stage of the Newtonian universe, on which all physical phenomena took place, was the three-dimensional space of classical Euclidean geometry. It was an absolute space, always at rest and unchangeable. In Newton’s own words, ‘Absolute space, in its own nature, without regard to anything external, remains always similar and immovable.’⁶ All changes in the physical world were described in terms of a separate dimension, called time, which again was absolute, having no connection with the material world and flowing smoothly from the past through the present to the future. ‘Absolute, true, and mathematical time,’ said Newton, ‘of itself and by its own nature, flows uniformly, without regard to anything external.’⁷

The elements of the Newtonian world which moved in this absolute space and absolute time were material particles. In the mathematical equations they were treated as ‘mass points’ and Newton saw them as small, solid, and indestructible objects out of which all matter was made. This model was quite similar to that of the Greek atomists. Both were based on the distinction between the full and the void, between matter and space, and in both models the particles remained always identical in their mass and shape. Matter was therefore always conserved and essentially passive. The important difference between the Democritean and Newtonian atomism is that the latter includes a precise description of the force acting between the material particles. This force is very simple, depending only on the masses and the mutual distances of the particles. It is the force of gravity, and it was seen by Newton as rigidly connected with the bodies it acted upon, and as acting instantaneously over a distance. Although this was a strange hypothesis, it was not investigated further. The particles and the forces between them were seen as created by God and thus were not subject to further analysis. In his Opticks, Newton gives us a clear picture of how he imagined God’s creation of the material world:

It seems probable to me that God in the beginning formed matter in solid, massy, hard, impenetrable, movable particles, of such sizes and figures, and with such other properties, and in such proportion to space, as most conduced to the end for which he formed them; and that these primitive particles being solids, are incomparably harder than any porous bodies compounded of them; even so very hard, as never to wear or break in pieces; no ordinary power being able to divide what God himself made one in the first creation.⁸

All physical events are reduced, in Newtonian mechanics, to the motion of material points in space, caused by their mutual attraction, i.e. by the force of gravity. In order to put the effect of this force on a mass point into a precise mathematical form, Newton had to invent completely new concepts and mathematical techniques, those of differential calculus. This was a tremendous intellectual achievement and has been praised by Einstein as ‘perhaps the greatest advance in thought that a single individual was ever privileged to make’.

Newton’s equations of motion are the basis of classical mechanics. They were considered to be fixed laws according to which material points move, and were thus thought to account for all changes observed in the physical world. In the Newtonian view, God had created, in the beginning, the material particles, the forces between them, and the fundamental laws of motion. In this way, the whole universe was set in motion and it has continued to run ever since, like a machine, governed by immutable laws.

The mechanistic view of nature is thus closely related to a rigorous determinism. The giant cosmic machine was seen as being completely causal and determinate. All that happened had a definite cause and gave rise to a definite effect, and the future of any part of the system could—in principle—be predicted with absolute certainty if its state at any time was known in all details. This belief found its clearest expression in the famous words of the French mathematician Pierre Simon Laplace:

An intellect which at a given instant knew all the forces acting in nature, and the position of all things of which the world consists—supposing the said intellect were vast enough to subject these data to analysis—would embrace in the same formula the motions of the greatest bodies in the universe and those of the slightest atoms; nothing would be uncertain for it, and the future, like the past, would be present to its eyes.⁹

The philosophical basis of this rigorous determinism was the fundamental division between the I and the world introduced by Descartes. As a consequence of this division, it was believed that the world could be described objectively, i.e. without ever mentioning the human observer, and such an objective description of nature became the ideal of all science.

The eighteenth and nineteenth centuries witnessed a tremendous success of Newtonian mechanics. Newton himself applied his theory to the movement of the planets and was able to explain the basic features of the solar system. His planetary model was greatly simplified, however, neglecting, for example, the gravitational influence of the planets on each other, and thus he found that there were certain irregularities which he could not explain. He resolved this problem by assuming that God was always present in the universe to correct these irregularities.

Laplace, the great mathematician, set himself the ambitious task of refining and perfecting Newton’s calculations in a book which should ‘offer a complete solution of the great mechanical problem presented by the solar system, and bring theory to coincide so closely with observation that empirical equations would no longer find a place in astronomical tables’.¹⁰ The result was a large work in five volumes, called Mécanique Céleste in which Laplace succeeded in explaining the motions of the planets, moons and comets down to the smallest details, as well as the flow of the tides and other phenomena related to gravity. He showed that the Newtonian laws of motion assured the stability of the solar system and treated the universe as a perfectly self-regulating machine. When Laplace presented the first edition of his work to Napoleon—so the story goes—Napoleon remarked, ‘Monsieur Laplace, they tell me you have written this large book on the system of the universe, and have never even mentioned its Creator.’ To this Laplace replied bluntly, ‘I had no need for that hypothesis.’

Encouraged by the brilliant success of Newtonian mechanics in astronomy, physicists extended it to the continuous motion of fluids and to the vibrations of elastic bodies, and again it worked. Finally, even the theory of heat could be reduced to mechanics when it was realized that heat was the energy created by a complicated ‘jiggling’ motion of the molecules. When the temperature of, say, water is increased the motion of the water molecules increases until they overcome the forces holding them together and fly apart. In this way, water turns into steam. On the other hand, when the thermal motion is slowed down by cooling the water, the molecules finally lock into a new, more rigid pattern which is ice. In a similar way, many other thermal phenomena can be understood quite well from a purely mechanistic point of view.

The enormous success of the mechanistic model made physicists of the early nineteenth century believe that the universe was indeed a huge mechanical system running according to the Newtonian laws of motion. These laws were seen as the basic laws of nature and Newton’s mechanics was considered to be the ultimate theory of natural phenomena. And yet, it was less than a hundred years later that a new physical reality was discovered which made the limitations of the Newtonian model apparent and showed that none of its features had absolute validity.

This realization did not come abruptly, but was initiated by developments that had already started in the nineteenth century and prepared the way for the scientific revolutions of our time. The first of these developments was the discovery and investigation of electric and magnetic phenomena which could not be described appropriately by the mechanistic model and involved a new type of force. The important step was made by Michael Faraday and Clerk Maxwell—the first, one of the greatest experimenters in the history of science, the second, a brilliant theorist. When Faraday produced an electric current in a coil of copper by moving a magnet near it, and thus converted the mechanical work of moving the magnet into electric energy, he brought science and technology to a turning point. His fundamental experiment gave birth, on the one hand, to the vast technology of electrical engineering; on the other hand, it formed the basis of his and Maxwell’s theoretical speculations which, eventually, resulted in a complete theory of electromagnetism. Faraday and Maxwell did not only study the effects of the electric and magnetic forces, but made the forces themselves the primary object of their investigation. They replaced the concept of a force by that of a force field, and in doing so they were the first to go beyond Newtonian physics.

Instead of interpreting the interaction between a positive and a negative charge simply by saying that the two charges attract each other like two masses in Newtonian mechanics, Faraday and Maxwell found it more appropriate to say that each charge creates a ‘disturbance’, or a ‘condition’, in the space around it so that the other charge, when it is present, feels a force. This condition in space which has the potential of producing a force is called a field. It is created by a single charge and it exists whether or not another charge is brought in to feel its effect.

This was a most profound change in our conception of physical reality. In the Newtonian view, the forces were rigidly connected with the bodies they act upon. Now the force concept was replaced by the much subtler concept, of a field which had its own reality and could be studied without any reference to material bodies. The culmination of this theory, called electrodynamics, was the realization that light is nothing but a rapidly alternating electromagnetic field travelling through space in the form of waves. Today we know that radio waves, light waves or X-rays, are all electromagnetic waves, oscillating electric and magnetic fields differing only in the frequency of their oscillation, and that visible light is only a tiny fraction of the electromagnetic spectrum.

In spite of these far-reaching changes, Newtonian mechanics at first held its position as the basis of all physics. Maxwell himself tried to explain his results in mechanical terms, interpreting the fields as states of mechanical stress in a very light space-filling medium, called ether, and the electromagnetic waves as elastic waves of this ether. This was only natural as waves are usually experienced as vibrations of something; water waves as vibrations of water, sound waves as vibrations of air. Maxwell, however, used several mechanical interpretations of his theory at the same time and apparently took none of them really seriously. He must have realized intuitively, even if he did not say so explicitly, that the fundamental entities in his theory were the fields and not the mechanical models. It was Einstein who clearly recognized this fact fifty years later when he declared that no ether existed and that the electromagnetic fields were physical entities in their own right which could travel through empty space and could not be explained mechanically.

At the beginning of the twentieth century, then, physicists had two successful theories which applied to different phenomena: Newton’s mechanics and Maxwell’s electrodynamics. Thus the Newtonian model had ceased to be the basis of all physics.

MODERN PHYSICS

The first three decades of our century changed the whole situation in physics radically. Two separate developments—that of relativity theory and of atomic physics—shattered all the principal concepts of the Newtonian world view: the notion of absolute space and time, the elementary solid particles, the strictly causal nature of physical phenomena, and the ideal of an objective description of nature. None of these concepts could be extended to the new domains into which physics was now penetrating.

At the beginning of modern physics stands the extraordinary intellectual feat of one man: Albert Einstein. In two articles, both published in 1905, Einstein initiated two revolutionary trends of thought. One was his special theory of relativity, the other was a new way of looking at electromagnetic radiation which was to become characteristic of quantum theory, the theory of atomic phenomena. The complete quantum theory was worked out twenty years later by a whole team of physicists. Relativity theory, however, was constructed in its complete form almost entirely by Einstein himself. Einstein’s scientific papers stand at the beginning of the twentieth century as imposing intellectual monuments—the pyramids of modern civilization.

Einstein strongly believed in nature’s inherent harmony and his deepest concern throughout his scientific life was to find a unified foundation of physics. He began to move towards this goal by constructing a common framework for electrodynamics and mechanics, the two separate theories of classical physics. This framework is known as the special theory of relativity. It unified and completed the structure of classical physics, but at the same time it involved drastic changes in the traditional concepts of space and time and undermined one of the foundations of the Newtonian world view.

According to relativity theory, space is not three-dimensional and time is not a separate entity. Both are intimately connected and form a four-dimensional continuum, ‘space-time’. In relativity theory, therefore, we can never talk about space without talking about time and vice versa. Furthermore, there is no universal flow of time as in the Newtonian model. Different observers will order events differently in time if they move with different velocities relative to the observed events. In such a case, two events which are seen as occurring simultaneously by one observer may occur in different temporal sequences for other observers. All measurements involving space and time thus lose their absolute significance. In relativity theory, the Newtonian concept of an absolute space as the stage of physical phenomena is abandoned and so is the concept of an absolute time. Both space and time become merely elements of the language a particular observer uses for describing the observed phenomena.

The concepts of space and time are so basic for the description of natural phenomena that their modification entails a modification of the whole framework that we use to describe nature. The most important consequence of this modification is the realization that mass is nothing but a form of energy. Even an object at rest has energy stored in its mass, and the relation between the two is given by the famous equation E= mc², c being the speed of light.

This constant c, the speed of light, is of fundamental importance for the theory of relativity. Whenever we describe physical phenomena involving velocities which approach the speed of light, our description has to take relativity theory into account. This applies in particular to electromagnetic phenomena, of which light is just one example and which led Einstein to the formulation of his theory.

In 1915, Einstein proposed his general theory of relativity in which the framework of the special theory is extended to include gravity, i.e. the mutual attraction of all massive bodies. Whereas the special theory has been confirmed by innumerable experiments, the general theory has not yet been confirmed conclusively. However, it is so far the most accepted, consistent and elegant theory of gravity and is widely used in astrophysics and cosmology for the description of the universe at large.

The force of gravity, according to Einstein’s theory, has the effect of ‘curving’ space and time. This means that ordinary Euclidean geometry is no longer valid in such a curved space, just as the two-dimensional geometry of a plane cannot be applied on the surface of a sphere. On a plane, we can draw, for example, a square by marking off one metre on a straight line, making a right angle and marking off another metre, then making another right angle and marking off another metre, and finally making a third right angle and marking off one metre again, after which we are back at the starting point and the square is completed. On a sphere, however, this procedure does not work because the rules of Euclidean geometry do not hold on curved surfaces. In the same way, we can define a three-dimensional curved space to be one in which Euclidean geometry is no longer valid. Einstein’s theory, now, says that three-dimensional space is actually curved, and that the curvature is caused by the gravitational field of massive bodies.

Wherever there is a massive object, e.g. a star or a planet, the space around it is curved and the degree of curvature depends on the mass of the object. And as space can never be separated from time in relativity theory, time as well is affected by the presence of matter, flowing at different rates in different parts of the universe. Einstein’s general theory of relativity thus completely abolishes the concepts of absolute space and time. Not only are all measurements involving space and time relative; the whole structure of space-time depends on the distribution of matter in the universe, and the concept of ‘empty space’ loses its meaning.

The mechanistic world view of classical physics was based on the notion of solid bodies moving in empty space. This notion is still valid in the region that has been called the ‘zone of middle dimensions’, that is, in the realm of our daily experience where classical physics continues to be a useful theory. Both concepts—that of empty space and that of solid material bodies—are deeply ingrained in our habits of thought, so it is extremely difficult for us to imagine a physical reality where they do not apply. And yet, this is precisely what modern physics forces us to do when we go beyond the middle dimensions. ‘Empty space’ has lost its meaning in astrophysics and cosmology, the sciences of the universe at large, and the concept of solid objects was shattered by atomic physics, the science of the infinitely small.

At the turn of the century, several phenomena connected with the structure of atoms and inexplicable in terms of classical physics were discovered. The first indication that atoms had some structure came from the discovery of X-rays; a new radiation which rapidly found its now Well known application in medicine. X-rays, however, are not the only radiation emitted by atoms. Soon after their discovery, other kinds of radiation were discovered which are emitted by the atoms of so-called radioactive substances. The phenomenon of radioactivity gave definite proof of the composite nature of atoms, showing that the atoms of radioactive substances not only emit various types of radiation, but also transform themselves into atoms of completely different substances.

Besides being objects of intense study, these phenomena were also used, in most ingenious ways, as new tools to probe deeper into matter than had ever been possible before. Thus Max von Laue used X-rays to study the arrangements of atoms in crystals, and Ernest Rutherford realized that the so-called alpha particles emanating from radioactive substances were high-speed projectiles of subatomic size which could be used to explore the interior of the atom. They could be fired at atoms, and from the way they were deflected one could draw conclusions about the atoms’ structure.

When Rutherford bombarded atoms with these alpha particles, he obtained sensational and totally unexpected results. Far from being the hard and solid particles they were believed to be since antiquity, the atoms turned out to consist of vast regions of space in which extremely small particles—the electrons—moved around the nucleus, bound to it by electric forces. It is not easy to get a feeling for the order of magnitude of atoms, so far is it removed from our macroscopic scale. The diameter of an atom is about one hundred millionth of a centimetre. In order to visualize this diminutive size, imagine an orange blown up to the size of the Earth. The atoms of the orange will then have the size of cherries. Myriads of cherries, tightly packed into a globe of the size of the Earth—that’s a magnified picture of the atoms in an orange.

An atom, therefore, is extremely small compared to macroscopic objects, but it is huge compared to the nucleus in its centre. In our picture of cherry-sized atoms, the nucleus of an atom will be so small that we will not be able to see it. If we blew up the atom to the size of a football, or even to room size, the nucleus would still be too small to be seen by the naked eye. To see the nucleus, we would have to blow up the atom to the size of the biggest dome in the world, the dome of St Peter’s Cathedral in Rome. In an atom of that size, the nucleus would have the size of a grain of salt! A grain of salt in the middle of the dome of St Peter’s, and specks of dust whirling around it in the vast space of the dome—this is how we can picture the nucleus and electrons of an atom.

Soon after the emergence of this ‘planetary’ model of the atom, it was discovered that the number of electrons in the atoms of an element determine the element’s chemical properties, and today we know that the whole periodic table of elements can be built up by successively adding protons and neutrons to the nucleus of the lightest atom—hydrogen*—and the corresponding number of electrons to its atomic ‘shell’. The interactions between the atoms give rise to the various chemical processes, so that all of chemistry can now in principle be understood on the basis of the laws of atomic physics.

These laws, however, were not easy to recognize. They were discovered in the 1920s by an international group of physicists including Niels Bohr from Denmark, Louis De Broglie from France, Erwin Schrödinger and Wolfgang Pauli from Austria, Werner Heisenberg from Germany, and Paul Dirac from England. These men joined their forces across all national borders and shaped one of the most exciting periods in modern science, which brought them, for the first time, into contact with the strange and unexpected reality of the subatomic world. Every time the physicists asked nature a question in an atomic experiment, nature answered with a paradox, and the more they tried to clarify the situation, the sharper the paradoxes became. It took them a long time to accept the fact that these paradoxes belong to the intrinsic structure of atomic physics, and to realize that they arise whenever one attempts to describe atomic events in the traditional terms of physics. Once this was perceived, the physicists began to learn to ask the right questions and to avoid contradictions. In the words of Heisenberg, ‘they somehow got into the spirit of the quantum theory’, and finally they found the precise and consistent mathematical formulation of this theory.

The concepts of quantum theory were not easy to accept even after their mathematical formulation had been completed. Their effect on the physicists’ imagination was truly shattering. Rutherford’s experiments had shown that atoms, instead of being hard and indestructible, consisted of vast regions of space in which extremely small particles moved, and now quantum theory made it clear that even these particles were nothing like the solid objects of classical physics. The subatomic units of matter are very abstract entities which have a dual aspect. Depending on how we look at them, they appear sometimes as particles, sometimes as waves; and this dual nature is also exhibited by light which can take the form of electromagnetic waves or of particles.

This property of matter and of light is very strange. It seems impossible to accept that something can be, at the same time, a particle—i.e. an entity confined to a very small volume—and a wave, which is spread out over a large region of space. This contradiction gave rise to most of the koan-like paradoxes which finally led to the formulation of quantum theory. The whole development started when Max Planck discovered that the energy of heat radiation is not emitted continuously, but appears in the form of ‘energy packets’. Einstein called these energy packets ‘quanta’ and recognized them as a fundamental aspect of nature. He was bold enough to postulate that light and every other form of electromagnetic radiation can appear not only as electromagnetic waves, but also in the form of these quanta. The light quanta, which gave quantum theory its name, have since been accepted as bona fide particles and are now called photons. They are particles of a special kind, however, massless and always travelling with the speed of light.

The apparent contradiction between the particle and the wave picture was solved in a completely unexpected way which called in question the very foundation of the mechanistic world view—the concept of the reality of matter. At the subatomic level, matter does not exist with certainty at definite places, but rather shows ‘tendencies to exist, and atomic events do not occur with certainty at definite times and in definite ways, but rather show ‘tendencies to occur. In the formalism of quantum theory, these tendencies are expressed as probabilities and are associated with mathematical quantities which take the form of waves. This is why particles can be waves at the same time. They are not ‘real’ three-dimensional waves like sound or water waves. They are ‘probability waves’, abstract mathematical quantities with all the characteristic properties of waves which are related to the probabilities of finding the particles at particular points in space and at particular times. All the laws of atomic physics are expressed in terms of these probabilities. We can never predict an atomic event with certainty; we can only say how likely it is to happen.

Quantum theory has thus demolished the classical concepts of solid objects and of strictly deterministic laws of nature. At the subatomic level, the solid material objects of classical physics dissolve into wave-like patterns of probabilities, and these patterns, ultimately, do not represent probabilities of things, but rather probabilities of interconnections. A careful analysis of the process of observation in atomic physics has shown that the subatomic particles have no meaning as isolated entities, but can only be understood as interconnections between the preparation of an experiment and the subsequent measurement. Quantum theory thus reveals a basic oneness of the universe. It shows that we cannot decompose the world into independently existing smallest units. As we penetrate into matter, nature does not show us any isolated ‘basic building blocks’, but rather appears as a complicated web of relations between the various parts of the whole. These relations always include the observer in an essential way. The human observer constitutes the final link in the chain of observational processes, and the properties of any atomic object can only be understood in terms of the object’s interaction with the observer. This means that the classical ideal of an objective description of nature is no longer valid. The Cartesian partition between the I and the world, between the observer and the observed, cannot be made when dealing with atomic matter. In atomic physics, we can never speak about nature without, at the same time, speaking about ourselves.

The new atomic theory could immediately solve several puzzles which had arisen in connection with the structure of atoms and could not be explained by Rutherford’s planetary model. First of all, Rutherford’s experiments had shown that the atoms making up solid matter consist almost entirely of empty space, as far as the distribution of mass is concerned. But if all the objects around us, and we ourselves, consist mostly of empty space, why can’t we walk through closed doors? In other words, what is it that gives matter its solid aspect?

A second puzzle was the extraordinary mechanical stability of atoms. In the air, for example, atoms collide millions of times every second and yet go back to their original form after each collision. No planetary system following the laws of classical mechanics would ever come out of these collisions unaltered. But an oxygen atom will always retain its characteristic configuration of electrons, no matter how often it collides with other atoms. This configuration, furthermore, is exactly the same in all atoms of a given kind. Two iron atoms, and consequently two pieces of pure iron, are completely identical, no matter where they come from or how they have been treated in the past.

Quantum theory has shown that all these astonishing properties of atoms arise from the wave nature of their electrons. To begin with, the solid aspect of matter is the consequence of a typical ‘quantum effect’ connected with the dual wave/particle aspect of matter, a feature of the subatomic world which has no macroscopic analogue. Whenever a particle is confined to a small region of space it reacts to this confinement by moving around, and the smaller the region of confinement is, the faster the particle moves around in it. In the atom, now, there are two competing forces. On the one hand, the electrons are bound to the nucleus by electric forces which try to keep them as close as possible. On the other hand, they respond to their confinement by whirling around, and the tighter they are bound to the nucleus, the higher their velocity will be; in fact, the confinement of electrons in an atom results in enormous velocities of about 600 miles per second! These high velocities make the atom appear as a rigid sphere, just as a fast rotating propeller appears as a disc. It is very difficult to compress atoms any further and thus they give matter its familiar solid aspect.

In the atom, then, the electrons settle in orbits in such a way that there is an optimal balance between the attraction of the nucleus and their reluctance to be confined. The atomic orbits, however, are very different from those of the planets in the solar system, the difference arising from the wave nature of the electrons. An atom cannot be pictured as a small planetary system. Rather than particles circling around the nucleus, we have to imagine probability waves arranged in different orbits. Whenever we make a measurement, we will find the electrons somewhere in these orbits, but we cannot say that they are ‘going around the nucleus’ in the sense of classical mechanics.

In the orbits, the electron waves have to be arranged in such a way that ‘their ends meet’, i.e. that they form patterns known as ‘standing waves’. These patterns appear whenever waves are confined to a finite region, like the waves in a vibrating guitar string, or in the air inside a flute (see diagram opposite). It is well known from these examples that standing waves can assume only a limited number of well-defined shapes. In the case of the electron waves inside an atom, this means that they can exist only in certain atomic orbits with definite diameters. The electron of a hydrogen atom, for example, can only exist in a certain first, second or third orbit, etc., and nowhere in between. Under normal conditions, it will always be in its lowest orbit, called the ‘ground state’ of the atom. From there, the electron can jump to higher orbits if it receives the necessary amount of energy, and then the atom is said to be in an ‘excited state’ from which it will go back to its ground state after a while, the electron giving off the surplus energy in the form of a quantum of electromagnetic radiation, or photon. The states of an atom, i.e. the shapes and mutual distances of its electron orbits, are exactly the same for all atoms with the same number of electrons. This is why any two oxygen atoms, for example, will be completely identical. They may be in different excited states, perhaps due to collisions with other atoms in the air, but after a while they will invariably return to exactly the same ground state. The wave nature of the electrons accounts thus for the identity of atoms and for their great mechanical stability.

A further characteristic feature of atomic states is the fact that they can be completely specified by a set of integral numbers, called ‘quantum numbers’, which indicate the location and shape of the electron orbits. The first quantum number is the number of the orbit and determines the energy an electron must have to be in that orbit; two more numbers specify the detailed shape of the electron wave in the orbit and are related to the speed and orientation of the electron’s rotation.* The fact that these details are expressed by integral numbers means that the electron cannot change its rotation continuously, but can only jump from one value to another, just as it can only jump from one orbit to another. Again the higher values represent excited states of the atom, the ground state being the one where all the electrons are in the lowest possible orbits and have the smallest possible amounts of rotation.

Tendencies to exist, particles reacting to confinement with motion, atoms switching suddenly from one ‘quantum state’ to another, and an essential interconnectedness of all phenomena—these are some of the unusual features of the atomic world. The basic force, on the other hand, which gives rise to all atomic phenomena is familiar and can be experienced in the macroscopic world. It is the force of electric attraction between the positively charged atomic nucleus and the negatively charged electrons. The interplay of this force with the electron waves gives rise to the tremendous variety of structures and phenomena in our environment. It is responsible for all chemical reactions, and for the formation of molecules, that is, of aggregates of several atoms bound to each other by mutual attraction. The interaction between electrons and atomic nuclei is thus the basis of all solids, liquids and gases, and also of all living organisms and of the biological processes associated with them.

In this immensely rich world of atomic phenomena, the nuclei play the role of extremely small, stable centres which constitute the source of the electric force and form the skeletons of the great variety of molecular structures. To understand these structures, and most of the natural phenomena around us, it is not necessary to know more about the nuclei than their charge and their mass. In order to understand the nature of matter, however, to know what matter is ultimately made of, one has to study the atomic nuclei which contain practically all of its mass. In the 1930s, after quantum theory had unravelled the world of atoms, it was therefore the main task of physicists to understand the structure of nuclei, their constituents and the forces which hold them together so tightly.

The first important step towards an understanding of nuclear structure was the discovery of the neutron as the second constituent of the nucleus, a particle which has roughly the same mass as the proton (the first nuclear constituent)—about two thousand times the mass of the electron—but does not carry an electric charge. This discovery not only explained how the nuclei of all chemical elements were built up from protons and neutrons, but also revealed that the nuclear force, which kept these particles so tightly bound within the nucleus, was a completely new phenomenon. It could not be of electromagnetic origin since the neutrons were electrically neutral. Physicists soon realized that they were here confronted with a new force of nature which does not manifest itself anywhere outside the nucleus.

An atomic nucleus is about one hundred thousand times smaller than the whole atom and yet it contains almost all of the atom’s mass. This means that matter inside the nucleus must be extremely dense compared to the forms of matter we are used to. Indeed, if the whole human body were compressed to nuclear density it would not take up more space than a pinhead. This high density, however, is not the only unusual property of nuclear matter. Being of the same quantum nature as electrons, the ‘nucleons’—as the protons and neutrons are often called—respond to their confinement with high velocities, and since they are squeezed into a much smaller volume their reaction is all the more violent. They race about in the nucleus with velocities of about 40,000 miles per second! Nuclear matter is thus a form of matter entirely different from anything we experience ‘up here’ in our macroscopic environment. We can, perhaps, picture it best as tiny drops of an extremely dense liquid which is boiling and bubbling most fiercely.

The essential new aspect of nuclear matter which accounts for all its unusual properties is the strong nuclear force, and the feature that makes this force so unique is its extremely short range. It acts only when the nucleons come very near to each other, that is, when their distance is about two to three times their diameter. At such a distance, the nuclear force is strongly attractive, but when the distance becomes less the force becomes strongly repulsive so that the nucleons cannot approach each other any closer. In this way, the nuclear force keeps the nucleus in an extremely stable, though extremely dynamic equilibrium.

The picture of matter which emerges from the study of atoms and nuclei shows that most of it is concentrated in tiny drops separated by huge distances. In the vast space between the massive and fiercely boiling nuclear drops move the electrons. These constitute only a tiny fraction of the total mass, but give matter its solid aspect and provide the links necessary to build up the molecular structures. They are also involved in the chemical reactions and are responsible for the chemical properties of matter. Nuclear reactions, on the other hand, generally do not occur naturally in this form of matter because the available energies are not high enough to disturb the nuclear equilibrium.

This form of matter, however, with its multitude of shapes and textures and its complicated molecular architecture, can exist only under very special conditions, when the temperature is not too high, so that the molecules do not jiggle too much. When the thermal energy increases about a hundredfold, as it does in most stars, all atomic and molecular structures are destroyed. Most of the matter in the universe exists, in fact, in a state which is very different from the one just described. In the centre of the stars exist large accumulations of nuclear matter, and nuclear processes which occur only very rarely on earth predominate there. They are essential for the great variety of stellar phenomena observed in astronomy, most of which arise from a combination of nuclear and gravitational effects. For our planet, the nuclear processes in the centre of the Sun are of particular importance because they furnish the energy which sustains our terrestrial environment. It has been one of the great triumphs of modern physics to discover that the constant energy flow from the Sun, our vital link with the world of the very large, is a result of nuclear reactions, of phenomena in the world of the infinitely small.

In the history of penetrating into this submicroscopic world, a stage was reached in the early 1930s when scientists thought they had now finally discovered the ‘basic building blocks’ of matter. It was known that all matter consisted of atoms and that all atoms consisted of protons, neutrons and electrons. These so-called ‘elementary particles’ were seen as the ultimate indestructible units of matter: atoms in the Demo-critean sense. Although quantum theory implies, as mentioned previously, that we cannot decompose the world into independently existing smallest units, this was not generally perceived at that time. The classical habits of thought were still so persistent that most physicists tried to understand matter in terms of its ‘basic building blocks’, and this trend of thought is, in fact, quite strong even today.

Two further developments in modern physics have shown, however, that the notion of elementary particles as the primary units of matter has to be abandoned. One of these developments was experimental, the other theoretical, and both began in the 1930s. On the experimental side, new particles were discovered as physicists refined their experimental techniques and developed ingenious new devices for particle detection. Thus the number of particles increased from three to six by 1935, then to eighteen by 1955, and today we know over two hundred elementary’ particles. The two tables opposite, taken from a recent publication,¹¹ show most of the particles known today. They illustrate convincingly that the adjective ‘elementary’ is no longer very attractive in such a situation. As more and more particles were discovered over the years, it became clear that not all of them could be called ‘elementary’, and today there is a widespread belief among physicists that none of them deserves this name.

This belief is enforced by the theoretical developments which paralleled the discovery of an ever-increasing number of particles. Soon after the formulation of quantum theory, it became clear that a complete theory of nuclear phenomena must not only be a quantum theory, but must also incorporate relativity theory. This is because the particles confined to dimensions of the size of nuclei often move so fast that their speed comes close to the speed of light. This fact is crucial for the description of their behaviour, because every description of natural phenomena involving velocities close to the speed of light has to take relativity theory into account. It has to be, as we say, a ‘relativistic’ description. What we need, therefore, for a full understanding of the nuclear world is a theory which incorporates both quantum theory and relativity theory. Such a theory has not yet been found, and therefore we have as yet been unable to formulate a complete theory of the nucleus. Although we know quite a lot about nuclear structure and about the interactions between nuclear particles, we do not yet understand the nature and complicated form of the nuclear force on a fundamental level. There is no complete theory of the nuclear particle world comparable to quantum theory for the atomic world. We do have several ‘quantum-relativistic’ models which describe some aspects of the world of particles very well, but the fusion of quantum and relativity theory into a complete theory of the particle world is still the central problem and great challenge of modern fundamental physics.

Relativity theory has had a profound influence on our picture of matter by forcing us to modify our concept of a particle in an essential way. In classical physics, the mass of an object had always been associated with an indestructible material substance, with some ‘stuff’ of which all things were thought to be made. Relativity theory showed that mass has nothing to do with any substance, but is a form of energy. Energy, however, is a dynamic quantity associated with activity, or with processes. The fact that the mass of a particle is equivalent to a certain amount of energy means that the particle can no longer be seen as a static object, but has to be conceived as a dynamic pattern, a process involving the energy which manifests itself as the particle’s mass.

This new view of particles was initiated by Dirac when he formulated a relativistic equation describing the behaviour of electrons. Dirac’s theory was not only extremely successful in accounting for the fine details of atomic structure, but also revealed a fundamental symmetry between matter and antimatter. It predicted the existence of an anti-electron with the same mass as the electron but with an opposite charge. This positively charged particle, now called the positron was indeed discovered two years after Dirac had predicted it. The symmetry between matter and antimatter implies that for every particle there exists an antiparticle with equal mass and opposite charge. Pairs of particles and antiparticles can be created if enough energy is available and can be made to turn into pure energy in the reverse process of annihilation. These processes of particle creation and annihilation had been predicted from Dirac’s theory before they were actually discovered in nature, and since then they have been observed millions of times.

The creation of material particles from pure energy is certainly the most spectacular effect of relativity theory, and it can only be understood in terms of the view of particles outlined above. Before relativistic particle physics, the constituents of matter had always been considered as being either elementary units which were indestructible and unchangeable, or as composite objects which could be broken up into their constituent parts; and the basic question was whether one could divide matter again and again, or whether one would finally arrive at some smallest indivisible units. After Dirac’s discovery, the whole question of the division of matter appeared in a new light. When two particles collide with high energies, they generally break into pieces, but these pieces are not smaller than the original particles. They are again particles of the same kind and are created out of the energy of motion (‘kinetic energy’) involved in the collision process. The whole problem of dividing matter is thus resolved in an unexpected sense. The only way to divide subatomic particles further is to bang them together in collision processes involving high energies. This way, we can divide matter again and again, but we never obtain smaller pieces because we just create particles out of the energy involved in the process. The subatomic particles are thus destructible and indestructible at the same time.

This state of affairs is bound to remain paradoxical as long as we adopt the static view of composite ‘objects’ consisting of basic building blocks’. Only when the dynamic, relativistic view is adopted does the paradox disappear. The particles are then seen as dynamic patterns, or processes, which involve a certain amount of energy appearing to us as their mass. In a collision process, the energy of the two colliding particles is redistributed to form a new pattern, and if it has been increased by a sufficient amount of kinetic energy, this new pattern may involve additional particles.

High-energy collisions of subatomic particles are the principal method used by physicists to study the properties of these particles, and particle physics is therefore also called ‘high-energy physics’. The kinetic energies required for the collision experiments are achieved by means of huge particle accelerators, enormous circular machines with circumferences of several miles in which protons are accelerated to velocities near the speed of light and are then made to collide with other protons or with neutrons. It is impressive that machines of that size are needed to study the world of the infinitely small. They are the supermicroscopes of our time.

Most of the particles created in these collisions live for only an extremely short time—much less than a millionth of a second—after which they disintegrate again into protons, neutrons and electrons. In spite of their exceedingly short lifetime, these particles can not only be detected and their properties measured but are actually made to leave tracks which can be photographed! These particle tracks are produced in so-called bubble chambers in a manner similar to the way a jet plane makes a trail in the sky. The actual particles are many orders of magnitude smaller than the bubbles making up the tracks, but from the thickness and curvature of a track physicists can identify the particle that caused it. The picture opposite shows such bubble chamber tracks. The points from which several tracks emanate are points of particle collisions, and the curves are caused by magnetic fields which the experimenters use to identify the particles. The collisions of particles are our main experimental method to study their properties and interactions, and the beautiful lines, spirals and curves traced by the particles in bubble chambers are thus of paramount importance for modern physics.

The high-energy scattering experiments of the past decades have shown us the dynamic and ever-changing nature of the particle world in the most striking way. Matter has appeared in these experiments as completely mutable. All particles can be transmuted into other particles; they can be created from energy and can vanish into energy. In this world, classical concepts like ‘elementary particle’, ‘material substance’ or ‘isolated object’, have lost their meaning; the whole universe appears as a dynamic web of inseparable energy patterns. So far, we have not yet found a complete theory to describe this world of subatomic particles, but we do have several theoretical models which describe certain aspects of it very well. None of these models is free from mathematical difficulties, and they all contradict each other in certain ways, but all of them reflect the basic unity and the intrinsically dynamic character of matter. They show that the properties of a particle can only be understood in terms of its activity—of its interaction with the surrounding environment—and that the particle, therefore, cannot be seen as an isolated entity, but has to be understood as an integrated part of the whole.

Relativity theory has not only affected our conception of particles in a drastic way, but also our picture of the forces between these particles. In a relativistic description of particle interactions, the forces between the particles—that is their mutual attraction or repulsion—are pictured as the exchange of other particles. This concept is very difficult to visualize. It is a consequence of the four dimensional space-time character of the subatomic world and neither our intuition nor our language can deal with this image very well. Yet it is crucial for an understanding of subatomic phenomena. It links the forces between constituents of matter to the properties of other constituents of matter, and thus unifies the two concepts, force and matter, which had seemed to be so fundamentally different ever since the Greek atomists. Both force and matter are now seen to have their common origin in the dynamic patterns which we call particles.

The fact that particles interact through forces which manifest themselves as the exchange of other particles is yet another reason why the subatomic world cannot be decomposed into constituent parts. From the macroscopic level down to the nuclear level, the forces which hold things together are relatively weak and it is a good approximation to say that things consist of constituent parts. Thus a grain of salt can be said to consist of salt molecules, the salt molecules of two kinds of atoms, those atoms to consist of nuclei and electrons, and the nuclei of protons and neutrons. At the particle level, however, it is no longer possible to see things that way.

In recent years, there has been an increasing amount of evidence that the protons and neutrons, too, are composite objects; but the forces holding them together are so strong or—what amounts to the same—the velocities acquired by the components are so high, that the relativistic picture has to be applied, where the forces are also particles. Thus the distinction between the constituent particles and the particles making up the binding forces becomes blurred and the approximation of an object consisting of constituent parts breaks down. The particle world cannot be decomposed into elementary components.

In modern physics, the universe is thus experienced as a dynamic, inseparable whole which always includes the observer in an essential way. In this experience, the traditional concepts of space and time, of isolated objects, and of cause and effect, lose their meaning. Such an experience, however, is very similar to that of the Eastern mystics. The similarity becomes apparent in quantum and relativity theory, and becomes even stronger in the ‘quantum-relativistic’ models of subatomic physics where both these theories combine to produce the most striking parallels to Eastern mysticism.

Before spelling out these parallels in detail, I shall give a brief account of the schools of Eastern philosophy which are relevant to the comparison for the reader who is not familiar with them. They are the various schools in the religious philosophies of Hinduism, Buddhism and Taoism. In the following five chapters, the historical background, characteristic features and philosophical concepts of these spiritual traditions will be described, the emphasis being on those aspects and concepts which will be important for the subsequent comparison with physics.

* The reader who finds this preliminary presentation of modern physics too compressed and difficult to understand should not be unduly worried. All of the concepts mentioned in this chapter will be discussed in greater detail later on.

* The hydrogen atom consists of just one proton and one electron.

* The ‘rotation’ of an electron in its orbit must not be understood in the classical sense; it is determined by the shape of the electron wave in terms of the probabilities for the particle’s existence in certain parts of the orbit.

II The Way of Eastern Mysticism

Chapter 5 Hinduism

For an understanding of any of the philosophies to be described, it is important to realize that they are religious in essence. Their main aim is the direct mystical experience of reality, and since this experience is religious by nature, they are inseparable from religion. More than for any other Eastern tradition this is true for Hinduism, where the connection between philosophy and religion is particularly strong. It has been said that almost all thought in India is in a sense religious thought and Hinduism has not only influenced, throughout many centuries, India’s intellectual life, but almost completely determined her social and cultural life as well.

Hinduism cannot be called a philosophy, nor is it a well defined religion. It is, rather, a large and complex socio-religious organism consisting of innumerable sects, cults and philosophical systems and involving various rituals, ceremonies and spiritual disciplines, as well as the worship of countless gods and goddesses. The many facets of this complex and yet persistent and powerful spiritual tradition mirror the geographical, racial, linguistic and cultural complexities of India’s vast subcontinent. The manifestations of Hinduism range from highly intellectual philosophies involving conceptions of fabulous range and depth to the naïve and childlike ritual practices of the masses. If the majority of the Hindus are simple villagers who keep the popular religion alive in their daily worship, Hinduism has, on the other hand, brought forth a large number of outstanding spiritual teachers to transmit its profound insights.

The spiritual source of Hinduism lies in the Vedas, a collection of ancient scriptures written by anonymous sages, the so-called Vedic ‘seers’. There are four Vedas, the oldest of them being the Rig Veda. Written in ancient Sanskrit, the sacred language of India, the Vedas have remained the highest religious authority for most sections of Hinduism. In India, any philosophical system that does not accept the authority of the Vedas is considered to be unorthodox.

Each of these Vedas consists of several parts which were composed at different periods, probably between 1500 and 500 B.C. The oldest parts are sacred hymns and prayers. Subsequent parts deal with sacrificial rituals connected with the Vedic hymns, and the last, called the Upanishads, elaborate their philosophical and practical content. The Upanishads contain the essence of Hinduism’s spiritual message. They have guided and inspired India’s greatest minds for the last twenty-five centuries, in accordance with the advice given in their verses:

Taking as a bow the great weapon of the Upanishad, One should put upon it an arrow sharpened by meditation. Stretching it with a thought directed to the essence of That, Penetrate that Imperishable as the mark, my friend.¹

The masses of the Indian people, however, have received the teachings of Hinduism not through the Upanishads, but through a large number of popular tales, collected in huge epics, which are the basis of the vast and colourful Indian mythology. One of those epics, the Mahabharata, contains India’s favourite religious text, the beautiful spiritual poem of the Bhagavad Gita. The Gita, as it is commonly called, is a dialogue between the god Krishna and the warrior Arjuna who is in great despair, being forced to combat his own kinsmen in the great family war which forms the main story of the Mahabharata. Krishna, disguised as Arjuna’s charioteer, drives the chariot right between the two armies and in this dramatic setting of the battlefield he starts to reveal to Arjuna the most profound truths of Hinduism. As the god speaks, the realistic background of the war between the two families soon fades away and it becomes clear that the battle of Arjuna is the spiritual battle of human nature, the battle of the warrior in search of enlightenment. Krishna himself advises Arjuna:

Kill therefore with the sword of wisdom the doubt born of ignorance that lies in thy heart. Be one in self-harmony, in Yoga, and arise, great warrior, arise.²

The basis of Krishna’s spiritual instruction, as of all Hinduism, is the idea that the multitude of things and events around us are but different manifestations of the same ultimate reality. This reality, called Brahman, is the unifying concept which gives Hinduism its essentially monistic character in spite of the worship of numerous gods and goddesses.

Brahman, the ultimate reality, is understood as the ‘soul’, or inner essence, of all things. It is infinite and beyond all concepts; it cannot be comprehended by the intellect, nor can it be adequately described in words: ‘Brahman, beginning-less, supreme: beyond what is and beyond what is not.’³

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