Einstein

by Philipp Frank

  Up to this time Einstein had solved his problems with the simplest mathematical aids and had looked upon every exaggeration in the use of “higher mathematics” with the suspicion that it was not due to any desire for clarity, but rather to dumbfound the reader. Now a new trend appeared in his work. It has been mentioned that while in Prague Einstein had already felt that the development of a still more general theory required more complicated mathematical methods than those he had at his command. He had discussed this matter with his colleague Pick, who had called his attention to the new mathematical theories of the Italians Ricci and Levi-Civita. In Zurich Einstein found among his colleagues his old friend Marcel Grossmann, and with him he now studied these new mathematical methods. In collaboration with him Einstein succeeded in preparing a preliminary sketch of a general theory of gravitation in which every case of the action of the force of gravity was contained. This work, published in 1913, still contained many defects, however, and they were not removed until the complete theory was finally published during the World War. We shall discuss it in detail later.

  2. Trip to Vienna

  In the fall of 1913, at the Congress of German Scientists and Physicians in Vienna, Einstein was invited to present a summary of his new ideas on the theory of gravitation. Even then he was regarded as an unusual phenomenon among the physicists, and it was rumored that he had “thought up” a general theory of relativity which was “even more incomprehensible” than his special theory of 1905 and even further removed from the physics of the laboratory. In consequence a large audience crowded the room where he was to speak. Einstein, however, took the most obvious and easily understood ideas as his points of departure and tried step by step to awaken in his listeners a feeling that radical changes were necessary if only one tried to see clearly the defects and gaps in the previous theories.

  His explanation was approximately as follows: At first, investigations of the nature of electricity were concerned only with electrical charges. The forces involved in the mutual attraction and repulsion of these charges were known, and it was also known that, like the Newtonian gravitational forces, they decreased with the square of the distance between the charges. Later, electric currents were discovered, and it was found that they could be generated by moving magnets, as well as by moving electric charges. This led to the industrial application of electricity. Finally, electromagnetic waves were discovered and utilized in wireless telegraphy and radio. No one had imagined that all this would develop from the simple attraction of electrical charges. In the theory of gravitation we are still in this first period where we are acquainted only with the law of attraction between material bodies. We must create a theory of gravitation that will be as far removed from the simple Newtonian theory of attractions as the theory of radio waves is from the views of Benjamin Franklin.

  In his lecture Einstein also mentioned that previous to his work a young Viennese physicist had already developed some of the mathematical ideas that he had used in his theory. He asked whether this man was in the audience, as he did not know him personally. And in fact a young man rose and Einstein asked him to remain standing so that the entire audience could see him. This man was Friedrich Kottler, later employed by the Eastman Kodak Company at Rochester, New York.

  Einstein took this opportunity of his stay in Vienna to become personally acquainted with the physicist and philosopher Ernst Mach, who had had such a profound influence on the development of Einstein’s ideas. (Ch. II) At the University of Vienna Mach had lectured on the history and theory of the “inductive” sciences — that is, sciences such as physics and chemistry that advance from individual observations to general laws. For more than twelve years, however, Mach had suffered from a severe paralysis and had retired from his position. He lived in his apartment in a suburb of Vienna, and occupied himself only with his studies and receiving occasional visitors. On entering his room one saw a man with a gray, unkempt beard and a partly good-natured, partly cunning expression on his face, who looked like a Slavic peasant and said: “Please speak loudly to me. In addition to my other unpleasant characteristics I am also almost stone-deaf.” Mach was very much interested in meeting the originator of the new theory of relativity.

  Even though Einstein greatly admired Mach’s ideas on the logical structure of physics, there were many things he could not accept. According to Einstein’s judgment Mach did not give enough credit to the creative mind of the scientist who imagines general laws beyond a mere economic description of facts. Mach’s opinion, that the general laws of science are only a means by which individual facts can be remembered more easily, did not appear satisfactory to Einstein. To him the phrase “remembered more easily” could in this connection apparently mean only “remembered with less effort.” Mach’s economy seemed to be economy in a psychological sense.

  Hence, after conversing awhile with Mach, Einstein raised the following question: “Let us suppose that by assuming the existence of atoms in a gas we were able to predict an observable property of this gas that could not be predicted on the basis of a non-atomistic theory. Would you then accept such a hypothesis even if the calculations of its consequence required very complicated computations, comprehensible only with great difficulty? I mean, of course, that from this hypothesis one could infer the interrelation of several observable properties that without it would remain unrelated. It is then ‘economical’ to assume the existence of atoms?”

  Mach answered: “If with the help of the atomic hypothesis one could actually establish a connection between several observable properties which without it would remain isolated, then I should say that this hypothesis was an ‘economical’ one; because with its aid relations between various observations could be derived from a single assumption. Nor should I have any objection even if the requisite computations were complicated and difficult.”

  Einstein was exceedingly satisfied with this statement and replied: “By ‘simple’ and ‘economical’ you mean, then, not a ‘psychological economy’ but rather a ‘logical economy.’ The observable properties should be derived from as few assumptions as possible, even though these assumptions appear ‘arbitrary’ and the computation of the results might be difficult.”

  With economy interpreted in this logical sense, there was no longer any conflict between Mach’s standpoint and Einstein’s as to the criteria to be filled by a physical theory. Although Mach made the concession in conversation, yet Einstein saw in his writing only a demand for “psychological economy.” Thus for the moment Einstein was satisfied, but he retained a certain aversion to the “Machist philosophy.”

  3. Invitation to Berlin

  Einstein’s fame had grown so great by now that many centers of scientific research desired to secure him as an associate. For several years efforts had been exerted to develop Berlin not only as a center of political and economic power but also as a center of artistic and scientific activity. Emperor Wilhelm II, who liked to associate with Americans, had learned from them that in the United States there were, in addition to the universities, institutions devoted solely to research, to which rich business men such as Rockefeller, Carnegie, and Guggenheim donated large sums of money. The Kaiser was aware that military and economic power required as a basis an organization of scientific research, and he wanted to use his influence to found similar research institutions in Germany. For his purpose this was particularly important in the fields of physics, chemistry, and their applications.

  To further these aims Wilhelm II founded the Kaiser Wilhelm Gesellschaft, within which rich industrialists, merchants, and bankers united to help build research institutes. The members received the pompous title of “senator” and the right to wear a handsome gown, and they were sometimes invited to breakfast with the Emperor — an invitation that cost them each time a great deal of money. During the course of the conversation at these breakfasts, the Emperor would mention that money was requested for a particularly important field of research.

  The erection of these i
nstitutes had the additional advantage that scientists whom the government did not want to appoint as professors in the universities, because of pedagogical, political, or other reasons, could still be employed in a way beneficial to the German Reich. Men of outstanding eminence were sought for these institutes, and the appointments could be made solely on the basis of scientific achievement.

  Owing to the fact that the Kaiser was interested not only in physics and chemistry but also in modern Biblical research, the first president of the Kaiser Wilhelm Gesellschaft was the liberal Protestant theologian Adolf Harnack. He was persuaded by Max Planck and Walter Nernst to invite Albert Einstein, the rising star in physics, to Berlin.

  Planck and Nernst, the leaders in German physics at this time, were to play important roles in Einstein’s life. They represented two very different types of German scientist. Max Planck was a member of a Prussian family of military officers and government officials. He was tall, slim, an enthusiastic mountain-climber, and a lover of classical music. Basically, he accepted the philosophy of his social class; he believed in the mission of the Kaiser to make the world happy with his conception of German culture, and in the right of his class to provide the leaders for Germany and to exclude people of other origins from such functions. On the other hand, he was an ardent adherent of Kantian philosophy in the diluted form in which it had become the common religion of the German academic and governmental circles. He believed with Kant in the duty of doing everything that is “qualified to become a general rule of human conduct.” He also believed in the international mission of science and in non-German co-operation with Germans in scientific research. But since his immediate emotional reaction was to respond in terms of the philosophy of the Prussian bureaucracy, an appeal to his reason was necessary to make him recognize the rights of aliens. As he was conscientious and an idealist, such an appeal was usually successful.

  On the other hand, Walter Nernst, although a great scientist and scholar, exhibited the mentality characteristic of a member of the merchant class. He had no national or class prejudice and was imbued with a type of liberalism that is often peculiar to business men. He was short, active, witty, and quick of apprehension. He occasionally utilized his craftiness in professional life, and his students jokingly referred to him as the “Kommerzienrat,” a title conferred in Germany on successful business men. There was a story about him that he was the only physicist who had ever signed a contract with an industrial firm in which the advantage was not on the side of the firm. This contract concerned his invention of an electric light bulb, widely known for a time as the Nernst lamp. He earned a good deal of money from it, but the lamp soon fell into disuse.

  Planck and Nernst went to Zurich personally to influence Einstein in favor of their plan. This was the following: There was as yet no separate research institute for physics and no hope that any such institute could be built in the near future. Nevertheless, Einstein was to become the director of the institute that was being planned, and in the meantime to assist in a consultative capacity in the physical research being carried on in other institutes. In addition he was to become a member of the Royal Prussian Academy of Science. To be a member of this body was considered a great honor; and many outstanding professors at the University of Berlin never succeeded in achieving it. Although membership in the Academy was only an honorary position for most of the incumbents, a few were endowed by foundations which paid a sufficiently large salary. Such a position was offered to Einstein. Both in the Academy and in the Kaiser Wilhelm Institute his main occupation was to be the organization of research. He was to have the title of professor at the University of Berlin, but unencumbered by any obligations or rights, except that of lecturing as much or as little as he desired. He was to have nothing to do with the administration of the university or with examinations, or in the appointment of new professors.

  There were great advantages offered by this invitation. Besides the academic honors that the Prussian Academy bestowed on him, it meant that he would receive a much larger salary than he did at Zurich. He would also be in a position to devote himself entirely to research and would have as much of an opportunity as he desired to come into contact with the many leading physicists, chemists, and mathematicians who were in Berlin. Despite his unusual talents he could still expect to be stimulated by new ideas, since it is always fruitful to receive the criticism of so many scientists capable of independent thinking, working in many different fields. In addition it meant that Einstein would not be obliged to give regular lectures, which he considered very burdensome.

  On the other hand, it was difficult for him to decide to return to the center of that Germany from which he had fled as a student. It seemed to him even a kind of betrayal of his convictions to become a member of a group with which he did not harmonize in so many respects, simply because it was connected with a pleasant position for himself. It was for him a struggle between his personality as a scientific investigator who could benefit by moving to Berlin, and his feeling as a member of a certain social group.

  In addition there were also personal factors that entered into the decision. Einstein had an uncle in Berlin a fairly successful businessman, whose daughter, Elsa, was now a widow. Einstein remembered that his cousin Elsa as a young girl had often been in Munich and had impressed him as a friendly, happy person. The prospects of being able to enjoy the pleasant company of this cousin in Berlin enabled him to think of the Prussian capital somewhat more favorably. And so Einstein finally decided to accept the offer, and at the end of 1913 he left Zurich.

  4. Einstein’s Position in the Academic Life of Berlin

  Soon after his arrival in Berlin Einstein separated from his wife, Mileva, with whom in many respects he was no longer in accord, and he now led a bachelor life. When he became a member of the Academy he was just thirty-four years old. He was a young man among men who were in general much older, men with proud pasts and great authority, and many of them of great achievements also. The feeling of strangeness that he felt there from the beginning, however, arose only in a very small part from the difference in age. Most of these men were, so to speak, “veterans of university life.” Everything that happened in these circles seemed to them extraordinarily important, and election to the Academy appeared to be the culmination of their aspirations. All this could not make any great impression on Einstein, who was already on his way to world fame before he was a great man in narrower academic circles.

  While Einstein was still in Zurich and a long time before the invitation from Berlin, someone happened to remark in his presence: “It is really a pity that no one ever enters the Academy while still a young man, at a time when it would still make him happy.” “If that is the case,” Einstein rejoined, “I could be elected to the Academy immediately, since it would not make me happy even now.”

  In an academy there is always much that is comical. Einstein appreciated this as much as he had the comedy in the faculty meetings at the University of Prague. Moreover, the comical aspects of such bodies are hardly to be avoided. This is due to the circumstance that even the greatest scientists of the country must deal with questions that are often of but slight significance, but that must be discussed with the same thoroughness and earnestness as if they were scientific questions of prime importance. For instance, whether a work to be published by the Academy is to be done in two or three volumes, whether A should receive one hundred marks for his work and B one hundred and twenty or vice versa, and many similar questions were discussed with considerable acumen and temperament. Also, in accordance with an old tradition, the papers that were to be printed in the transactions of the Academy had to be presented, even if only in summary form when the Academy met. Since as a rule these papers dealt with very special subjects, they were completely incomprehensible and uninteresting to most of the members. One described a rare moss found in a certain part of Finland, another discussed the solution of a complicated mathematical equation, and still another the deciphering of a Babylonia
n inscription that could be read only with difficulty. In order to be polite, one had to show a certain interest; actually the members often had to make an effort not to fall asleep during the sessions. This was all very natural, but the contrast between earnestness and triviality could not but appear comical. Einstein was well able to appreciate this, and his sense of humor made it easier for him to endure much that was unpleasant.

  Professor Ladenburg, a German physicist who lived and worked for a long time with Einstein in Berlin and who is now at Princeton University, once said to me: “There were two kinds of physicists in Berlin: on the one hand was Einstein, and on the other all the rest.” This is a very good characterization of Einstein’s position. To all outward appearances he was a member of a professional group, but he never belonged to its rank and file. His aloofness was always noticeable, and his status may be described aptly by the slang expression: “He was in a class by himself.”

  Einstein’s contradictory attitude toward co-operation with others and his aloofness we have so often noted manifested itself also very definitely in his attitude to his occupation as professor. He frequently expressed the opinion that a scientist should earn his living from a “cobbler’s job.” If he is paid to discover new theories he must constantly be thinking: “Discoveries cannot be made on order and if I don’t discover anything, I shall disappoint my employers and receive my pay for nothing.” But if he is active as a technician or a teacher, he is always doing something useful and hence has a clear conscience. On his own ideas he should work for pleasure only.