[Editor's Note] The movie "Oppenheimer" was released recently and sparked heated discussions. The famous physicist Mr. Yang Zhenning has direct contact with almost all the scientists who appear in the film - Yang Zhenning's doctoral supervisor is Edward Taylor, the "father of the hydrogen bomb". In an interview, Yang Zhenning directly mentioned the changes in political attitudes and views of scientists such as Oppenheimer, Taylor, Fermi, and Wigner at that time, providing us with valuable information. The author of this article, Hou Yude, is a professor and doctoral supervisor at the Institute of History of Science and Technology at Shanxi University. The original title of this article is "Chen-Ning Yang Talks about Scientists and Politics and Science and Philosophy - An Interview with Chen-Ning Yang on May 6, 2016", which first appeared in the 9th issue of "Physics" in 2021. ThePaper Technology was authorized to reprint by the Journal Network of the Chinese Physical Society.

In December 2015, the author was invited by Mr. Yang Zhenning and had the honor to give a lecture at the Institute for Advanced Study of Tsinghua University. During this period, I had two long conversations with Mr. Yang. After communicating via email, both parties felt the need to have in-depth exchanges on some issues again. On the morning of May 6, 2016, the author visited Mr. Yang again and asked him for advice and confirmation on some issues. The recording of this part of the conversation is relatively clear, but the text has not been published since it was compiled. As Mr. Yang celebrates his 100th birthday today, I would like to dedicate this article to readers, which will help to fully and deeply understand the inner world of Mr. Yang Chenning.

Taken at Mr. Yang Zhenning’s home on May 6, 2016

Hou Yude: Hello, Mr. Yang! Nice to see you again! Your complexion feels much better than it did in December last year.

Yang Zhenning: Older people are naturally afraid of the cold. In summer, when the weather warms up, the body will feel much more comfortable than in winter.

Hou Yude: Then let me get straight to the point. The first topic I want to ask you about today is related to when I came to see you in December last year. That time, under your arrangement, I gave a lecture at the Institute for Advanced Study, Tsinghua University. At that time, you were unable to come in person due to business reasons. After the report, one of the issues we (Academician Zhu Bangfen, Professor Qin Kecheng, Professor Ge Weikun, Professor Lou Yuqing, etc.) discussed together was the topic of scientists and politics. Scientists can be roughly divided into two categories, such as Max Born, Enrico Fermi, etc. They are more willing to do scientific research and teaching, rather than directly engaging in social management related to politics; Some people, on the contrary, are more good at or even enthusiastic about this kind of affairs, such as Oppenheimer (Robert Oppenheimer), and Taylor (Edward Teller) and Lindemann (Fredrick Lindemann (Churchill's adviser) and so on). This topic involves a person named von Neumann, who was your colleague at Princeton, right?

Chen Ning Yang: Yes, von Neumann was my colleague at Princeton. He was more than ten years older than me.

Hou Yude: In a biography of von Neumann, the biographer said that von Neumann had an extreme viewpoint. He not only participated in social and political affairs, but also actively suggested that the United States should engage in nuclear deterrence during the Cold War, calling for Engage in preemptive strikes. In my opinion this is an extreme idea bordering on madness. The book states that the philosopher and mathematician Bertrand Russell was the main promoter of pre-emptive warfare, while von Neumann was tougher and keen on surprise pre-emptive strikes with nuclear weapons1). Is the von Neumann you saw really so extreme and tyrannical?

Yang Zhenning: Some of what you said is true, but I think your explanation may not be correct. For example, von Neumann and Taylor's political views were not always like this from the beginning, but gradually evolved into this. This evolution is closely related to the development and changes of the entire world situation. Your explanation divides people into two categories. In reality, people are not divided into two categories. Between the two extremes, the distribution of people is continuous. In addition, a person's position in politics is changing all the time. I think so, some people do their own research exclusively and don't care about other things; some people care about other things besides their own research. These two different human natures are very obvious, and this phenomenon has existed in ancient and modern times, both in China and abroad. Oppenheimer was a very smart physicist when he was young, but he was also very interested in what happened in the world, so he joined many leftist organizations in the United States in the 1930s. But this does not mean that he wants to devote himself to politics at this time, he just thinks this is what a modern person should do. As for Fermi, it's not that he has no interest in these things, but he doesn't join this organization or that organization. Looking back, the Chinese are the same, some Chinese physicists like to express their opinions on politics, and some don't. When the entire world situation changes, it also affects everyone's development direction. For example, Oppenheimer had a close relationship with many left-leaning organizations in the 1930s. Later, the US government selected him as an important person in charge of the atomic bomb. So you can also say that this pushed his life's destiny from the original direction of mainly doing physics to another direction. After this change happened, his personal strengths were brought into play, but in the end it also brought him a blow. So what I want to say is that you cannot predetermine whether this person belongs to this faction or that person belongs to that faction. They change with time and the situation. Another example is Taylor, he is my mentor. When he was my teacher, he mainly did physics research, but for special reasons, Oppenheimer asked him to research and manufacture hydrogen bombs, which changed the trajectory of his life. It was more accidental that Oppenheimer asked Taylor to study the hydrogen bomb. Oppenheimer's real purpose was not because he felt that hydrogen bomb research was really necessary at the time, the fact was the opposite. Teller was one of many physicists Oppenheimer called to study the atomic bomb. They were about the same age and their relationship was good at that time. There is a theoretical group in the Manhattan Project, and the two very important people in it are Hans Bethe and Taylor, and Bethe is the team leader (thick: he later won the Nobel Prize). Yes, Bate is famous, he wrote 3 long articles2) in the 1930s, published in Reviews of Modern Physics. Later, when I was a graduate student, these articles became classic must-read works in nuclear physics, so Oppenheimer asked Bate to be the leader of the theory group. As a result, after a few days of research, Bate came to Oppenheimer and said that Taylor was playing a negative role in our group. What reason? Bate said: Because Taylor has a lot of new insights, he would talk about two or three new insights every morning, and the attention of the young people in the group was attracted by his new insights. Taylor was in the theory group, It has seriously distracted everyone, especially young people, from concentrating on the work of developing the atomic bomb. This problem must be solved. Oppenheimer said: What can we do? Taylor wouldn't be happy if you moved him out. As a result, Oppenheimer came up with a clever solution. Because Taylor is an unrestrained person who likes to think about new things. After thinking about it, Oppenheimer said: Well, get Taylor. Then he said to Taylor, you should be the leader of a team specializing in hydrogen bombs. Oppenheimer's original intention was to get Taylor out of Bate's theoretical group, so Taylor was very happy. Taylor found a few people to form a group, he was the head, specializing in how to make hydrogen bombs. For this reason, in 1942 he began to study the hydrogen bomb, which determined the fate of Taylor's later life. So you can see that there are also some accidental factors here. Oppenheimer thought: first, the hydrogen bomb is illusory and cannot be produced for a while; second, anyway, if he is asked to do this, it will solve Bate's problem. This event not only determined Taylor's life, but also had a certain impact on the development of the entire world political structure. 3)

Yang Zhenning and Oppenheimer at the Fifth International Conference on High Energy Physics in 1955丨Image source: AIP Digital Collections

Hou Yude: You used Taylor's involvement in the study of hydrogen bombs as an example to illustrate that scientists' choices of some jobs and even life paths have a certain degree of contingency. And this is often related to the development of external events. This understanding makes sense. Scientists are just like everyone else. Their ideas, ambitions, etc. cannot be completely isolated from society. Related to this, you said earlier that Oppenheimer had connections with various leftist organizations in the United States at that time, and later there were hearings about him, and these actions of his have become relevant evidence, right?

Chen Ning Yang: The incident you are talking about happened in 1954. In the 1950s, from now on, Oppenheimer had a great influence in the whole of the United States, especially in Washington, because he presided over the atomic bomb. After the atomic bomb exploded, the whole world paid great attention to it. His status, especially in the U.S. Congress, has a huge influence. But then, in 1949, Harry Truman issued an order, saying that the United States would go all out to develop the hydrogen bomb. The reason was that the United States discovered that the Soviet Union had also produced an atomic bomb, and Truman made the decision to study the hydrogen bomb. After making the decision, Taylor was very proud, because this was what he wanted to do, so he asked someone to come and invite these young people to work with him to study how to make a hydrogen bomb. He felt that due to Oppenheimer's influence, some young people were unwilling to go, so from 1949, their relationship became very bad. (Hou: It turns out that the relationship between the two of them had become tense since 1949.) The quarrel was not in front of their faces, but behind their backs. Taylor later said: I went to this person, and this person was not interested in developing a hydrogen bomb; I went to that person, and that person was not interested in developing a hydrogen bomb either. These people were all influenced by Oppenheimer. This is not an open fight, but a secret fight. This later spread to the political circles. Because Taylor wanted to develop hydrogen bombs, he had close relations with the US military, especially the Department of the Air Force, the Department of the Navy, and the Department of the Army. The Air Force was the most active in developing hydrogen bombs because Taylor He has a very close relationship with the U.S. Air Force and the Secretary of the Air Force. The U.S. military wants to develop a hydrogen bomb. From their standpoint, the military will become stronger when the hydrogen bomb is developed. On the other hand, developing a hydrogen bomb country requires a lot of money, which is also mixed with the private interests of some people in the military. In any case, Taylor got together with the military, especially the Air Force. But in the process of promoting this matter, he found that there was huge resistance from Oppenheimer. He realized that only by canceling Oppenheimer's power and influence could they develop the hydrogen bomb smoothly. This is the background of the hearing in 1954, and they went to Dwight Eisenhower, and at the direction of Eisenhower, his people wrote a letter to Oppenheimer, saying that we are going to stop you from participating in the U.S. For national defense work, we give you a choice. The first choice is that you automatically quit, which is the best choice. Second, if you disagree and choose to investigate why the government no longer allows you to participate in national defense work, then we will hold a hearing. It turned out that Oppenheimer didn't opt out, so there was a hearing later. The hearing was one of the major events in the world at that time, so you can see that it was not possible to say in advance whether this person belongs to this faction or that person belongs to that faction; the formation of this situation is very important to the development of the entire international situation Relationship.

On December 15, 1957, Princeton, USA, Robert Oppenheimer, the creator of the atomic bomb. Visual China Data Map

Hou Yude: From this point of view, the appearance of the hearing in 1954 was facilitated step by step, and it can be said that it has a direct relationship with Taylor. The core problem is that he believes that Oppenheimer is a stumbling block preventing him from developing the hydrogen bomb.

Yang Zhenning: Of course it has a lot to do with Taylor, but there are many reasons for the hearing, and Taylor is only one of them. One of the most famous and interesting things in the hearing was: the organizer of the hearing invited Taylor to sit in the town. Taylor could agree or disagree. Many of his friends did not agree to his participation. I have nothing to do with this matter. I am his student, and another student of my contemporary Taylor is called Rosenbluth. He told Taylor not to go to the hearing, but to participate in the public speaking, which caused a lot of controversy. In the end, he still went. Why did everyone advise him not to go? Because this matter is very complicated, why do you need to be entangled in it? He must go. He later said that before he went, he walked up and down in the hotel room until midnight, thinking about how he should answer people's questions, and he came up with a passage. After the hearing, someone asked him: Dr. Taylor, do you think Dr. Oppenheimer is loyal to the United States? So Taylor moved out a passage he prepared in the hotel, which later became very famous: "I don't think Dr. Oppenheimer is unpatriotic, but I don't understand some of his words and deeds, so if the security cause of the United States does not I feel safer in the hands of Oppenheimer." 4) You see, he didn't say that Oppenheimer was not patriotic, but because he didn't understand his words and deeds, the national defense was in the hands of Oppenheimer. worried. This sentence was later generally interpreted as: He wants to drive away Oppenheimer, which will have a great impact on the rest of Taylor's life in the future, because Taylor's character makes him need friends, but in this way, 99% of physics Everyone ignored him.

Hou Yude: At that time, Oppenheimer was very prestigious in the industry and showed excellent leadership skills.

Yang Zhenning: For the vast majority of scientists, this is the case.

Hou Yude: Taylor's words offended Oppenheimer and left a very bad impression on most physicists.

Yang Zhenning: Yes. Speaking of which, the conflict between Taylor and Oppenheimer may have something to do with another matter. In the 20th century, there were three important figures in the American scientific community, one was Taylor, the other was von Neumann, and the other was Eugene Wigner, who later won the Nobel Prize. I know all three of them very well. They were both Hungarians, both Jews who had grown up in Budapest, and both were important physicists and mathematicians. They were firmly anti-communist, so their opposition to Oppenheimer was more or less closely related to their background, because they believed that Oppenheimer was pro-leftist. Therefore, there are very complicated reasons for what a person becomes in the end. It is too simple to say that some people like to have a relationship with politics, and some people do not like to have a relationship with politics. Some people's final life results cannot be determined by themselves, and the role of external others cannot be ignored sometimes.

Hou Yude: I didn't know that Wigner was also firmly anti-communist.

Chen Ning Yang: He is too, he is very anti-communist, and he is more than just anti-communist. I knew Wigner very well, he was twenty years older than me5). During the three years of natural disasters in China in the early 1960s, I heard that many people in China starved to death. One day I went to Wigner's office to discuss some issue. The discussion came up again and again, and China came up. He said he was in favor of bombing Beijing with atomic bombs. I can't remember how I got to this point. I think we must have talked about this issue unknowingly when we were discussing physics. I said that China is miserable now, and the United States should help China, but his attitude towards China is very unfriendly, not only does not approve of aid, but also supports the United States to bomb Beijing. As a result, after returning home, I wrote him a letter, further showing that I had a completely different attitude from him.

Hou Yude: Can you still find it after writing this letter?

Yang Zhenning: If I find this letter, I can show it to you. Wigner is a person who likes to think very much. He is a very good physicist. From the perspective of research, I like him. He proposed parity very early, and he was also the first to apply group theory and symmetry to physics. I also engaged in this, but later than him, so I admire him very much. I also admire many aspects of his personal life. But we have fundamental differences when it comes to politics or our views on society. There is another story related to Wigner. In the 1930s, he went from Europe to the United States6), and he was in Princeton when he first went, but he didn't get a permanent position, so he went to other places in the middle. 7) This may have been 1938 or 1939. At that time, I couldn’t remember whether it was Zhou Peiyuan or someone else, so I wanted to invite him to China. If you go to Tsinghua University and Peking University to check the archives, you should be able to find relevant historical materials. Later this matter did not work out 8). In the middle, Wigner went to work at the University of Wisconsin for two years, and then returned to Princeton9). I don't know why he left? Came back after two years. But I know that he seemed to be dissatisfied with the treatment given to him by Princeton, so he left. I mention this just to say that the three of them are firmly anti-communist. But their attitudes on whether to participate in politics are completely different. The three people are good friends, but they are completely different in terms of attitude and demeanor. 10)

Hou Yude: Zhou Peiyuan was one of the well-known professors who had a good relationship with the Western physics community at that time. I read Born's biography and found that after 1933, Born wrote to Mr. Zhou, expecting him to help arrange work for his students and assistants. In 1936, Mr. Zhou Peiyuan also wrote back to Born, saying that Tsinghua hoped to get a scholar, but the plan at that time was to implement it after the normalization of relations with Japan. In fact, Japan's aggression became more rampant in the future, and this matter could only be abandoned 11). After you wrote to Wigner, did the letter affect your personal relationship?

Yang Zhenning: It has no impact. He did not answer my letter. In fact, he could not answer me. My purpose was to express my attitude. Later, we continued to interact. I invited him to my house for dinner, and he invited me to his house for dinner, and he never mentioned it again.

Hou Yude: You mentioned in your previous writings that the two of you had a lot of contacts. In the article you gave me last year 12) mentioned the paper he collaborated with Jordan. His name was written in the front, but he said that actually When the contribution is greater.

Yang Zhenning: Yes, this is also one of his personality, honesty in doing things. This story made a deep impression on me, so I wrote it down. He was indeed a very honest man again. 13)

Hou Yude: Wigner is a generation older than you. Do all theoretical physicists of that generation think highly of him? These only rely on books are very limited.

Yang Zhenning: This involves another relationship. Many people, including me, speak highly of him, but many others think he is not good. Theoretical physicists have a lot of different opinions about how much math to know, like Werner Heisenberg, I guess he felt that Wigner was not a very good physicist all his life, he thought Wigner was too mathematical melted. (H: He also has the same attitude towards Born) Yes, he is like this to Born, and it is even more like this to Wigner, because Wigner is a very good mathematician, and his attitude and knowledge of mathematics are far superior to Born's. Well, so Heisenberg looked down on such physicists when he was young. In his later years, after winning the Nobel Prize, Wigner said: When I was young, none of my work was valued by others. Today, no matter whether my work is right or not, it is valued by others. Niels Bohr and Heisenberg belittled physical work related to mathematics. But Heisenberg also changed in his later years. He realized that he could do nothing without mathematics.

Hou Yude: Indeed, I can find enough evidence for this. When Born was in Göttingen, there were several young people around him who were tired of Born's excessive use of mathematics, possibly even Fermi when he was in Göttingen. I think it is understandable that some young people studying physics have this idea. But Fermi's later mathematics was strong.

Yang Zhenning: Yes. Fermi was very unhappy when he was in Göttingen. I think the main thing is that Heisenberg and Pauli (Wolfgang Pauli) looked down on him at that time, which had a great impact on his self-confidence. At that time Pauli and Heisen Bodu is very famous. Later, Fermi went to Leiden University in the Netherlands and stayed with Paul Ehrenfest for half a year. He later said that during these six months he regained his self-confidence.

Hou Yude: According to Born's memories, Fermi showed a very smart and capable side when he was in Göttingen.

Yang Zhenning: If you can write an article about what Fermi did in Göttingen, and then discuss his relationship with Heisenberg, Pauli and Born at that time, I think it will be very important work.

Hou Yude: The key is as you said. He has a bit of a tense relationship with the people you mentioned or other people, but there is nothing between him and Born. From the biography written by Mrs. Fermi for Fermi, it can be seen that Born is still friendly to Fermi. But it didn't say that others treated Fermi badly.

Chen Ning Yang: I have read the biography of Mrs. Fermi, but I didn’t notice it 14).

Hou Yude: There is currently no direct evidence in the literature that others are unfriendly to Fermi. It is generally believed that it is because Born is introverted, and any student who takes the initiative to approach him will have more exchanges with him. But Fermi himself was also introverted, so they gradually drifted apart or always maintained a distance. These are understandable but difficult to demonstrate.

Chen Ning Yang: Some information may be revealed in the letters between Heisenberg and Pauli. You can find evidence of this in these letters and articles from the time, which are important historical documents.

Hou Yude: What you said makes sense and is worth paying attention to when conditions permit. Fermi was a remarkable experimental and theoretical physicist, a master of both. Apart from that, I think he is a very rational person. Oppenheimer established the Atomic Energy Commission, which included Leo Szilard and others, but Fermi withdrew voluntarily. He said: I can not quit, but I can't guarantee that I can make the right conclusion. As a physicist, he can judge whether his work is right or wrong, but when it comes to matters of such human complexity, he feels unsure, not knowing whether his vote is right or wrong, and once he has this feeling , he felt that he should quit. This also fully demonstrates his honesty and pragmatism as a scientist.

Yang Zhenning: I have also heard about this incident. Oppenheimer was impressed by Fermi's answer, so he told me.

Hou Yude: Is this what Oppenheimer told you directly?

Yang Zhenning: He told me personally. Because he knew that I was Fermi's proud student, he went to talk to Fermi but failed and he came back. Oppenheimer obviously noticed this and admired it, so he told me about Fermi's resignation from the Atomic Energy Commission. There is also a story related to Fermi15) about Hanchun (Joan Hinton, 1921-2010). She worked as an assistant to Fermi in his laboratory at Los Alamos, where she did the important work of developing the atomic bomb. After the war, Fermi went to Chicago, and Hanchun became a graduate student at the University of Chicago, and hadn't started writing a thesis yet. We have known each other since 1947, and she asked me to teach her Chinese. She didn’t explain why she was learning Chinese at the time, but the next year she suddenly said that she was going to China, and I didn’t know the purpose of her learning Chinese. I still remember very clearly that she was going to take the train from Chicago to San Francisco, and then take the boat to Shanghai. In March 1948, I borrowed a car and took her to the Chicago train station, and then she started her journey to China. After she arrived in China, we passed several postcards, but unfortunately lost them all. When I returned to China for the first time in 1971, someone arranged for me to visit Dazhai. Unexpectedly, I happened to meet her in Dazhai, and we talked for a long night. Some people later said that it must have been deliberately arranged by the government, but I don't think so. Why did I go to Dazhai then? Because the government wants me to know the achievements of learning from Dazhai in agriculture. Why did she go, because her brother (Han Ding) was a member of the Communist Party, he returned to the United States a few years ago, and returned to China for the first time in 197116), she led her brother around the agricultural areas of China. So chance is very large, not intentional arrangement. During the conversation that night, she told me such a story. When she wanted to come to China in 1948, she said, "I think I must tell Fermi about this matter." Because the atomic bomb research she and Fermi did is a sensitive matter, she said, after thinking about it for a long time, she finally told Fermi. M She is going to China. She was very afraid at the time, fearing that Fermi would tell Washington her plan, which would prevent her from coming to China. As a result, Fermi didn't tell Washington, so no one stopped her. She said: "Because of this incident, I will forever thank him." I think her words are very important, so when I returned to the United States, I immediately called Mrs. Fermi and said that I met Han Chun in China and told the story. In particular, tell her Hanchun's gratitude to Fermi.

Hou Yude: Then can I imagine what would happen if Ms. Hanchun’s mentor was not Fermi? Likely to end her trip to China.

Yang Zhenning: She knew Fermi very well when she was a graduate student, but Fermi was not her advisor. This incident can well show Fermi's character.

Hou Yude: In the 1960s and 1970s, documentary films about Dazhai were often played in rural areas. I learned about Dazhai through movies. How did you feel when you visited Dazhai?

Yang Zhenning: They did a good job of publicity. Chen Yonggui entertained me. Those who went to visit all stayed in the hostel, and Hanchun also lived there, so we met. Chen Yonggui took us to see the fields that Dazhai people cultivated by themselves.

Hou Yude: Combining these things, I have a deeper understanding of Fermi. Born said that some scientists have forgotten their own work, and it is too much to fully devote themselves to political activities, and believes that this is related to human personality. I think there is some truth to what he said. Some people are active and committed, while others are withdrawn and timid.

Yang Zhenning: This is a very complicated issue. For fame, power and money, everyone in different industries around the world has their own judgments. The living environment and personality are different. A slightly different judgment may result in the final result of life. There is a big difference, so the final result is closely related to the environment in which people grow up and the social turmoil at that time. In this regard, there is also a difference between the traditional Chinese Confucian way of life and the West. Traditional Confucian concepts such as self-cultivation and etiquette are relatively conservative. The West does not object to this, but they do not pay enough attention to it, so they are more outward-looking, while Confucianism is more inward-looking. There is a difference in this point. The impact of this cultural difference on people cannot be ignored. This kind of cultural distinction of who is good and who is bad is not a question that can be answered easily. In different situations and in different times, there will be different ideas.

Oppenheimer learned from Einstein. Visual China Data Map

Hou Yude: Since we mentioned Oppenheimer, Fermi and the atomic bomb, this reminds me of Einstein. At that time, Einstein, Szilard and others jointly wrote a letter to the President of the United States, suggesting the development of an atomic bomb. Did you find this letter useful?

Chen Ning Yang: I think this letter worked, but it didn’t play a big role. Unfortunately, some people in China's academic circles are ill-informed and express their opinions indiscriminately. After Einstein's letter was sent, it was initially ignored by the U.S. government. This is not surprising, since the government is so big that it usually doesn't care about academia. Einstein is very famous, but many people think he is an old gentleman, outdated now, and a person who has little connection with the world, so it is not surprising that people in the US government are not interested in this letter. But then I didn’t know what happened in it. As a result, the U.S. government became interested in this letter again, so when the U.S. started to build an atomic bomb, it was related to this letter. So I said that this letter did not have a big impact, and the impact was not immediate, but it did have an impact in the end. I think this is the most accurate evaluation. I told you about Peng Yue last time. He studied the history of the atomic bomb and read more than ten thick books before he wrote a good article. Some scholars in China do not study hard and are therefore ill-informed. The opinions expressed in this way will inevitably lead to errors.

Hou Yude: You are right. In fact, as far as I know, there are some scholars in China who are very rigorous in their research work. But as long as there is a human population, there tends to be an approximate normal distribution. China's market economy was rife with counterfeiting in the early days. Later, businessmen discovered that they could not sustainably make money through deception. Therefore, economically developed regions consciously became more standardized and the quality of their products became better and better. I hope China’s academic community will do the same. When I was talking about the atomic bomb just now, I suddenly had an idea: When your mentor Taylor was working on the hydrogen bomb, you had the opportunity to intervene. Why didn't you intervene?

In 1949, Yang Zhenning (27 years old) was photographed in front of the physics building of the University of Chicago. Visual China Data Map

Chen Ning Yang: I left Chicago in 1949, and I have been at Princeton for the next 17 years. I can occasionally see Taylor, because he sometimes comes to Princeton for meetings, and I can also see him at meetings of the American Physical Society, but in general, rare. Most of the time when we meet, we just talk about hello and how are you. After I left Chicago, I had several long conversations with him, none of which had anything to do with hydrogen bomb research. The first time I had a relatively long communication with him, which lasted only half an hour or less than an hour, was when I visited Berkeley in the summer of 1955. He asked me to have a talk, and the talk had nothing to do with nuclear weapons. I remember two things we talked about. One was that he asked questions about gauge fields, because at that time my article with Mills had been published. He was probably mildly interested, and he asked me a few questions, but nothing in depth. Another thing is that he told me (pause to think)... I don’t remember whether it was me who proposed it or him. It may have been me who proposed it, but we talked about the following matter. At that time, the whole world knew about his conflict with Oppenheimer. I remember I told him that I thought it would be best for him to do something to make up for it. How to make up for it? Because he has just received the Enrique Fermi Award from the President of the United States17). Fermi died in 1954. When he was very ill before his death, the United States Congress passed a decree to establish an Enrique Fermi Award. There were a lot of bonuses at that time, and the first one was given to Fermi18), this award has always existed, and there are still 19). So I said to Tyler, you just won the Fermi Award, why don't you nominate Oppenheimer once? Taylor was later nominated for Oppenheimer, who won the Fermi Award the following year. But I guess this cannot be attributed to me. I think he thought of it himself, and I believe others will remind him that this is a good way to make up for it. But at least I remember talking to him about it. I remember that I may have written him a letter about this matter later.

Hou Yude: You mentioned the letter, so I will trouble you again. If you find the letter you gave Wigner, please show me it.

Yang Zhenning: All right. I go on to think about Taylor. Taylor and I never discussed the issue of the hydrogen bomb. Later, we had such a contact. I went to Beijing in 1971. The incident attracted great attention and was published in American newspapers at the time. He paid attention to it, because first, I was his student, and second, he had a great influence in Washington at that time. He has a nephew who is a professor, and I know him very well. I think he is almost 80 now, and he said that his uncle is coming to see him, and he wants to talk to me about China. So that day he only invited Taylor and me to his house for dinner. After the meal, Taylor took me to a room, and his nephew led his wife away. Taylor and I talked alone. Obviously Taylor wants to know information about China, and I am willing to tell him. We talked for several hours. Speaking of his impression of China, he does not like the Communist Party, but he is not as fierce as Wigner, who once said that he would bomb Beijing.

Hou Yude: Speaking of this, I think I need to confirm, is Wigner talking about bombing in the general sense, or bombing with nuclear weapons? Can this be discerned in the context of the time?

Yang Zhenning: This conversation was relatively early, not to say that they really made a plan to bomb Beijing. I feel that Wigner said this mainly to express his opposition to the Chinese Communist Party. But if the U.S. government did discuss the matter, Wigner would support the bombing opinion. What we talked about that night was that Taylor wanted to know what was going on in China, and he wanted to know what my opinion was on China. Is it possible that he wants to test whether I want to return to China? I can't tell. He knew that I had nothing to do with atomic weapons. He would guess that China very much wanted me to go back, not just to do scientific work. He guessed that if I returned to China, China would let me do work on the atomic bomb. I thought he might test my opinion. Taylor is very familiar with the US military. The military may ask him to test me. Is this possible? This is a very complex issue. Because I am a well-known physicist in the United States, ordinary people outside the scientific community, such as those in the U.S. military, think that physicists and atomic bombs are very close, but in fact they are not. For another example, when I went to Hong Kong at the end of 1964, my father, mother, brothers and sisters came to Hong Kong from Shanghai. We met and stayed together for two weeks. Later, when I returned to Princeton, there was a professor named George Kennan, who was an important figure in American diplomacy and one of the important figures in diplomatic theory. In the 1940s, the United States and the Soviet Union became two camps. How should the United States handle its relationship with the Soviet Union at that time? At that time, there was an article that invented a concept called containment policy, which is to surround and prevent people from coming out. This is the most important thing in diplomatic theory after the Second World War. The author died four or five years ago. , he is a few years older than me. He later became a professor at Princeton. In 1964, I separated from my parents and returned to the United States from Hong Kong. He invited me to dinner and asked me a lot about the news about China that I had received from my parents. I later guessed that he might also want to test whether I wanted to return to China after contacting my parents. I guess this was probably the U.S. Department of Foreign Affairs asking him to test it out. In other words, there are people in the US government who are very concerned about whether Yang Zhenning returns to China. Before returning to China in 1971, I wrote a letter to the Science Advisor to the President of the United States. Why did I write a letter to him? If I suddenly show up in China without telling him, there may be disputes. I think it would be better if I tell him in advance. I wrote him a letter, and he replied that he was happy for me to come back to China for a visit, but he could not give me a visa. In fact, I did not need his help at that time. Not long after this incident, a classmate I had not seen for many years at the University of Chicago suddenly came to see me. I think I had not heard from him for at least ten years at that time. He stayed at my house for a day, and I later guessed that he might have come here under the instruction of some department in the United States to test things out. Why do I think so? After studying at the University of Chicago, he worked as a journalist and was stationed in Hong Kong. He did one thing in Hong Kong, which was the most important thing in his life. He visited Zhang Guotao in Hong Kong and wrote a biography of Zhang Guotao, which established his career in journalism. status among journalists because Zhang Guotao is an important historical figure. So I guessed that he had some relationship with the US government, but I didn't ask him about it later. So when these people, including Taylor, came to visit, I more or less felt that they were trying to test whether Yang Chenning wanted to return to China.

Hou Yude: Thank you for talking so much about the first topic. Part of it is something I have known before, and part of it is the first time I heard about it. That's a lot of information and I think we can end the first question here. The second question I look forward to asking you today is about the relationship between physics and philosophy. Few people who do experimental physics seem to care about this issue. Some theoretical physicists are concerned about it. For example, Bohr especially likes to discuss philosophy. Born sometimes said that philosophy is important and requires students to have an understanding of philosophy. However, he also warned students not to completely surrender to any philosophical school, but to Maintain a questioning and critical spirit. There are also some theoretical physicists such as Fermi and Feynman who have an unfriendly or even dismissive attitude towards philosophy. I noticed that your previous view on this was that you believed that philosophy had a positive significance for physics earlier in history, but with the development of physics, the influence of philosophy on physics has become increasingly weakened. . How do you see the relationship between the two now?

Chen Ning Yang: Regarding the relationship between philosophy and physics, yes, the views of the physics community are different in different eras. In other words, this relationship is constantly changing with the changes of the times and the evolution of physics. In the 19th century, following the tradition that science was called natural philosophy, science and philosophy were still believed to be closely related. By the end of the 19th century, many scientists still believed that physics was almost born out of philosophy, and Mach's influence was particularly great. But if you look at today, even when I was doing research at the frontiers of physics in the 20th century, none of the physicists who were actually doing research paid attention to philosophy. This represents a great change in physicists' views on philosophers' philosophy 20) between the 19th and 20th centuries. This change appears in different people. Of course, among physicists of the same era, some like to talk philosophy and some don’t. You are right. For example, Bohr liked to talk about philosophy, while Fermi did not like to talk about philosophy. This kind of difference is inevitable. This may be because different people have different hobbies. The key to the question is whether philosophy really guides the research of physics, and whether physicists cannot leave philosophy. At least judging from the physicists of our generation, I don’t think so.

Hou Yude: In fact, a reversal has taken place today. As you once said, it is not philosophy that influences or guides physics research, but physics that influences the development of philosophy.

Yang Zhenning: Yes, to be more specific, I think the development of quantum mechanics is a good example. Quantum mechanics does not come from philosophy. Although some people think so, I don’t think so; it is obvious that quantum mechanics comes from philosophy. It was established based on the study of atomic spectroscopy. After the development of quantum mechanics, it in turn had a great influence on the philosophical world, and this process is still continuing.

Hou Yude: The microscopic world that quantum mechanics focuses on is fundamentally different from the macroscopic world. In the first 30 years of the 20th century, this field was not only unfamiliar and new to physicists, but also the research results were completely new to philosophers. Therefore, he must absorb, learn, and understand this new thing, and this process will inevitably occur. Your personal opinion is that there is absolutely no need for a physicist to study philosophical works first, and then use them to form his own way of thinking, thereby affecting the research work of physics.

Yang Zhenning: We must respect the objective facts of the scientific research process. I have never studied philosophy, and none of the theoretical physicists I have met treat philosophy as if they must learn and use mathematics. Sakata Shoichi believes that theoretical physics research needs philosophical guidance, I said 21), I disagree with him saying that his research originated from philosophy, he can’t draw conclusions in physics from philosophy, I think the less he involves philosophy , the greater the physical achievements.

Hou Yude: In this way, your basic views on the relationship between physics and philosophy are highly consistent with those 30 years ago. Thank you for your clear answer to my question.

Note:

1) Written by William Poundstone, translated by Wu Heling. The Prisoner's Dilemma. Beijing: Beijing Institute of Technology Press, 2005, 5 pages.

2) In his biography, Wigner also mentioned these articles published by Bate from 1936 to 1937, calling them "wonderful papers". For details, see Chapter 10, page 149, of "Scholar in Troubled Times——Wigner's Autobiography" published by Shanghai Science and Technology Education Press in 2001.

3) The Manhattan Project involved a large number of top-notch physicists with personalities, and their interpersonal relationships were complicated. From the perspective of different people, there are many different stories. Mr. Yang Zhenning's story about Oppenheimer's proper arrangement of Taylor has a certain echo in Taylor's biography, for example, it says: "After arriving in Chicago, he (referring to Taylor) was not assigned any specific work. In addition to melancholy, he kept My mind turned back to the theoretical discussion of the hydrogen bomb.” For details, see: Stanley Bloomberg and Gwen Owens, translated by Hua Junduo and Zhao Shuyun. Taylor, the father of the American hydrogen bomb. Beijing: Atomic Energy Press, 1991, 118 pages.

4) The Taylor biographer, from Taylor's perspective, argues: "In the postwar years, Edward Teller found Oppenheimer's political views not only disturbing but sometimes elusive." This was especially true in 1953. For details, see: Stanley Bloomberg and Gwen Owens, translated by Hua Junduo and Zhao Shuyun. Taylor, the father of the American hydrogen bomb. Beijing: Atomic Energy Press, 1991, p. 299. So it seems that Taylor's famous quote is not only his carefully wise and lethal phrasing, but perhaps at least partly his true inner thoughts.

5) Mr. Yang Zhenning remembered very accurately that Wigner was born in 1902 and Mr. Yang was born in 1922.

6) Wigner himself said in his biography that in October 1930, he received a one-semester lecturer seat from Princeton University in Berlin, and he came to the United States. Out of satisfaction with the work of Wigner and von Neumann, who arrived almost at the same time as him, Princeton University proposed that in the next five years, the two of them can work at Princeton University for half a year, and go where they want for half a year. European jobs. In 1935-1936 Princeton offered Wigner a full-time visiting professorship. For details, see pages 147-148 of chapters 9 and 10 of "A Scholar in Troubled Times——Wigner's Autobiography" published by Shanghai Science and Technology Education Press in 2001.

7) Wigner says in his biography that Princeton fired him in 1936. He was then offered an acting professorship at the University of Wisconsin-Madison. For details, see pages 153 and 157 of Chapter 10 of "A Scholar in Troubled Times--Wigner's Autobiography" published by Shanghai Science and Technology Education Press in 2001.

8) Combined with Wigner's own recollection, Princeton University had once again provided Wigner with a teaching position in 1938, so it can be inferred that Zhou Peiyuan's plan to introduce Wigner may have been earlier than 1938-1939.

9) On June 13, 1938, Princeton University once again provided Wigner with the post of professor of mathematical physics. For details, see Chapter 10, page 161, of "Scholar in Troubled Times——Wigner's Autobiography" published by Shanghai Science and Technology Education Press in 2001.

10) Yang Zhenning once said that American scientists such as Oppenheimer and Taylor showed their sharpness and flaunted themselves. For details, see: Yang Zhenning. Heart Road in Sixty-eight Years: 1945—2012. Beijing: Life·Reading·New Knowledge Sanlian Bookstore, 2014 edition, p.233. But Yang Zhenning said: "Wigner is sincere and unsmiling, which is completely different from the arrogant attitude of American scientists." For details, see: Yang Zhenning, compiled by Weng Fan. Dawn Collection. Beijing: Life·Reading·New Knowledge Sanlian Bookstore, 2008 Annual edition, page 53.

11) For details, see page 187 of Hou Yude's article "Interpretation of a letter written by Born to Peng Huanwu" published in the 3rd issue of "Physics" in 2015.

12) See: YANG C N. Fermi's β-decay theory. International Journal of Modern Physics A, 2012(3&4), 27:1-7.

13) Chen Ning Yang used this to point out that Chinese scholars and some Chinese people he saw were not honest in their actions and speeches, and he was critical and worried about this.

14) In Fermi's biography, Mrs. Fermi wrote: "Born himself was kind and hospitable." For details, see page 33 of "The Biography of Fermi" published by The Commercial Press in 1998.

15) In Yang Zhenning's "Dawn Collection" published by Life, Reading and New Knowledge Sanlian Bookstore in 2008 (Han Chun was still alive at that time), Yang Zhenning once told the general outline of this story. For details, see pages 314-315 of the book.

16) The accurate fact is: Hinton went to China with the United Nations Relief Administration in 1947 and came to the liberated areas to resume production and train agricultural machinery personnel. He did not return to the United States until 1953. In 1971, he returned to China at the invitation of Premier Zhou after many years of absence.

17) The information shows that Taylor won the Fermi Award in 1962, so Mr. Yang said that they talked about nominating Oppenheimer in 1955, and the time memory may be inaccurate.

18) Current information shows that the first winner of the Fermi Award was von Neumann, who was mentioned many times before. Maybe Mr. Yang’s memory is wrong.

19) Chen Ning Yang won the Fermi Award in 1979.

20) Yang Zhenning once pointed out that philosophy has two meanings. One is the philosophy of philosophers; the other is the long and medium distance (or even short distance) views on physical problems. This view is extremely closely related to a person's style and preferences. For details, see pages 513-514 of "Collected Works of Yang Zhenning" published by East China Normal University Press in 1998.

21) Yang Zhenning made this statement in his report at the Graduate School of the University of Science and Technology of China (Beijing) in 1986. For details, see page 514 of "Collected Works of Yang Zhenning" published by East China Normal University Press in 1998.