Tabibito (The Traveler)

The following sections are included:

• Contents

• Foreword

• Chronological Table

When Hideki Yukawa graduated from Kyoto University in 1929 and began research on nuclear theory, the knowledge of nuclear physics accumulated since the start of the century had led to a crisis. It was believed that electrons and protons must be the constituents of the nucleus, for they were observed, in special circumstances, leaving the nucleus, and because they were the only known elementary material particles — yet this picture contradicted quantum mechanics…

Many people think that Kyoto is my hometown. It is actually the place where I received most of my education. After graduating from the University in Kyoto, I lived for a time in the vicinity of Osaka, but then I returned. When I came back from America in 1957, I did not feel that I was “home” until the train approached Kyoto through the Tōyama tunnel…

I was in Japan for a short time in the summer of 1949, between trips to the United States, and in that particular summer there was a reunion of my former elementary school class attended by about twenty of us. That so many were present after thirty years was surprising, as there were fewer than one hundred in my class. That may also have to do with the city of Kyoto, where many people tend to carry on family trades, even today. Most Kyoto women marry in or near the city; and, of course, Kyoto was not damaged in the war…

Very old and very new things co-existed in my house during my childhood.

My maternal grandfather, Komakitsu, was a samurai who spent all his days at Wakayama Castle, before the Meiji Restoration (1868). His learning in Chinese classics was enormous, but he studied European culture after Meiji and habitually read The London Times…

Meiji — the name reminds me of water in a flask over an alcohol flame, gradually heating up and boiling over. My early years were spent toward the end of that period, but I cannot recall how the Japanese people mourned the passing era; I was only a little more than five years old. My older brothers probably knew many stories of Emperor Meiji; te only thing in my memory is a book that my mother gave me. It was a fold-out picture of a long funeral procession of people in full court regalia. I looked at it every day without comprehending its meaning; I did not know that The Meiji Era had ended and the Taisho Era had begun…

The formula for the sum of an arithmetic progression is known to everyone who has learned algebra in middle school, but I devised it by myself. The equation itself was unknown to me, but I was doing the same operation as it expressed. In later years, when my brothers gathered at the house at Tonodan, they talked with my mother about my boyhood days, and this story about the arithmetic progression came up. My older brother wanted to interpret the discovery as a flash of creativity onmy part, but I never thought of it that way; I had almost forgotten that it had occurred. It just happened that mathematics, or arithmetic in elementary school, was my best subject…

Did my temperament finally make me reject the understanding of those around me? My father, Takuji, said that I was the kind of person who always made his own decisions, and he added: “I cannot even guess what Hideki is thinking about.” My brothers were probably more open than I was. Tamaki, who was my junior, had a straightforward personality and was the most trusted in the family. I was the middle one of the five brothers; I was the valley in which no light could enter; and what cold wind blew, or what rivers ran in that valley, even my father could not guess. The saying: “No one knows the child better than his father,” my oldest brother, Yoshiki, once said, “does not apply to Hideki and our father.” Perhaps that was so…

If you had just walked across a meadow and then were told that it contained a pitfall, a deep one with no way out, you would shudder. Moreover, that pitfall was covered with grass and would be unnoticeable even if you walked right up to it! My rather ordinary life seems to have contained such a danger, but I learned about its existence some thirty years later. Thus, it had little impact upon me, and still seems not quite believable. My mother told the story to an acquaintance, so I cannot simply say it is untrue. In a way, this episode may even add some depth to my life's story…

If one considers its earliest foundation in Osaka (after which it changed its name many times), the Third High School is just as old as the First Middle School. The school moved to Kyoto in the eighteenth year of Meiji, and it took the name Third High School in the twenty-seventh year of Meiji (1894). The high school was just to the north of the First Middle School, and long before that school, it had the motto, “Freedom.” So both literally and psychologically, to enter this school was merely a matter of moving next door. The entrance examination was not a problem; I had no worry about it as I did very well in the mathematics questions…

Can a human being grow, at the same time maintaining a perfect harmony? Is it not the case that any period of growth, viewed in retrospect, shows great imbalance? After the Second World War, when the Japanese economy was in its darkest days, many who were very young had to endure the buffeting of the rough waves of society. It was natural for them to develop an interest in the nature of society. By comparison, the time of my boyhood was, at least for me, quite peaceful. My parents provided for my education, and there was no necessity for part time work by students as there is today. Of course, there were some prototypes of the behavior of modern high school teenagers. The parents of conservative families called them delinquent. One often heard descriptions like “delinquent youths,” but it did not really sound too serious. There was that sort of “delinquent“ even in the Third High School…

On a recent day when the weather turned summery, I walked over to the main building of Kyoto University, which I had not seen for some time. I usually spend my days in the Research Institute for Fundamental Physics, on the North Campus, not far from the main building located just across Imadegawa Street. However, because I was busy, and also lazy about going out for a walk, I generally do not step out of the Institute during the day unless I absolutely must…

In March of the fourth year of Showa, a little before my graduation from Kyoto University, I began to have misgivings. If I were to continue doing physics, it might come to nothing. I was so pessimistic that I even thought of becoming a priest. My distaste for society, present since middle school days, lifted its head at that time. A dislike for society resides within me even today, although it is more a desire to avoid contact than an active dislike. I want my interactions with other people cut down to about one-tenth, and I want to live quietly. If no one paid any attention to me, that would probably mean a lonely life; but to endure the loneliness would not be so bad, either. That sort of wish, a quite unrealistic kind of wishful dream, gives me comfort…

I had lived in Kyoto ever since I was aware of my surroundings, but I knew next to nothing about the city of Osaka. I became a resident of Osaka because of my marriage. The train station at Umeda was small and cluttered, but it had an attraction quite different from the station at Kyoto. In it I felt the liveliness that fills all of Osaka. Large old houses lined the streets of Uchiawaji. The Yokobori River flowed steadily to the west, people continuously crossing its numerous bridges. Everyone moved briskly; in contrast to Kyoto's natural beauty, there were lively human beings here. One reason why I decided to live in Osaka was that I wanted to let myself be changed by this new environment…

The following sections are included:

• Epilogue

• On the Interaction of Elementary Particles. I.

• Appendix