Rodney Allen Brooks - Fields of Color: The Theory That Escaped Einstein

People like you and me, though mortal, of course, like everyone else, do not grow old no matter how long we live. What I mean is that we never cease to stand like curious children before the great Mystery into which we are born. Albert Einstein (, p. 82)

When I was 14, I read Arthur Eddingtons The Nature of the Physical World . I remember how excited I was to learn that a desk is not a solid piece of furniture. If you could look closely enough, said Eddington, beyond the power of any microscope, you would see that it is made of atoms so tiny that we can hardly grasp their tinyness. These atoms are made of even tinier nuclei, and these in turn are made of particles called neutrons and protons, while little electrons whiz around them in orbits like miniature solar systems. So that is what the world is made of, I thought, and this was the first step in my eventual decision to make physics my career. Of course it didnt occur to me then to wonder what electrons, protons and neutrons are made of.

Some time later, as a graduate student, I attended a three-year lecture series at Harvard University by Julian Schwinger. The timing was perfect. Schwingers development of Quantum Field Theory (QFT) had matured and he was about to publish a monumental work, A theory of the fundamental interactions. I sat mesmerized, as did others.

Attending one of [Schwingers] formal lectures was comparable to hearing a new major concert by a very great composer, flawlessly performed by the composer himself The delivery was magisterial, even, carefully worded, irresistible like a mighty river Crowds of students and more senior people from both Harvard and MIT attended I felt privileged and not a little daunted to witness physics being made by one of its greatest masters. Walter Kohn, Nobel laureate (, p. 593-4)

As Schwinger stood at the blackboard, writing ambidextrously and speaking mellifluously in well-formed sentences, it was as if God Himself was handing down the Ten Commandments. The equations were so elegant that it seemed the world couldnt be built any other way. From the barest of principles, he derived the equations of QFT, even including the gravitational field. Not only was the mathematics elegant, but the philosophic concept of a world made of properties of space seemed to me much more satisfying than Eddingtons mysterious particles. I was amazed and delighted to see how the paradoxes of relativity theory and quantum mechanics that I had found so baffling disappeared or were resolved.

Later on, I must admit, things got more complicated as the number and variety of fundamental fields grew, and quarks entered the scene. But to my knowledge, QFT remains as the true fabric of which the world is made. Whats more, I believe it is the only fabric of which the world could be made.

Unfortunately, Schwinger, once called the heir-apparent to Einsteins mantle by J. Robert Oppenheimer, never had the impact he should have had on the world of physics or on the public at large. Instead, the more colorful and outgoing Richard Feynman came to the fore. It is his image, not Schwingers, that is enshrined on a postage stamp. It is possible that Schwingers very elegance was his undoing.

Julian Schwinger was one of the most important and influential scientists of the twentieth century Yet even among physicists, recognition of his fundamental contributions remains limited, in part because his dense formal style ultimately proved less accessible than Feynmans more intuitive approach. However, the structure of modern theoretical physics would be inconceivable without Schwingers manifold insights. His work underlies much of modern physics, the source of which is often unknown even to the practitioners. His legacy lives on not only through his work, but also through his many students, who include leaders in physics and other fields. J. Mehra and K.A. Milton (, p. v)

In the 50 years that passed since my student days, I have seen very little mention of QFT in its true fields-only sense. Instead I have seen a bombardment of books and articles that keep repeating the paradoxes that people are expected to accept. Physical intuition has disappeared or, worse yet, is sneered at. Far from bringing to the public an understanding of nature, these popular books and articles have brought confusion and chaos. This hit me hard one day as I was reading Joseph Hellers memoir, Now and Then . Heller is the author of Catch 22 , one of my all-time favorites, and when I read that he tried to understand quantum mechanics and had to give it up (see quote in ), I knew that something was badly wrong. And so I decided to write a book.

My mission soon turned into a labor of love, with emphasis on labor. I had not anticipated the breadth and depth of the subject, or the drama as our greatest minds waged what I think is our greatest battle: to understand the world we find ourselves in (a far more worthy battle than the wars we are so good at waging against each other). By drama, I mean not only the philosophic struggle to wrest natures secrets from their most hidden recesses with only the flimsiest of evidence. I also mean the human side of the story stories that are sometimes tragic, sometimes nettlesome, but always fascinating.

This book is my attempt to bring to the public the same satisfaction and understanding that I felt in Schwingers courses, and to dispel the paradoxes of physics that prevent so many people from understanding the natural world. The book is aimed at two audiences. The primary audience consists of those who, like Heller, have made some attempt to understand modern physics and found it to be incomprehensible. The other audience is those people who have not read much about physics, but who would like to learn about it in a way they can understand. I hope that my efforts will bear fruit and that the reader will come away from the book feeling that nature is not mysterious or paradoxical, but is understandable and indeed makes perfect sense.