Einstein (33 page)

This became generally known and the session was awaited as if it were a sensational and decisive meeting of a parliament. Max Planck presided. This great scientist and distinguished man detested any kind of sensation. He endeavored to arrange the session in such a way so as to keep the debate on the level on which scientists usually discuss matters and to prevent nonscientific points of view from being brought into it. He arranged it so that the greatest part of the available time was filled with papers that were purely mathematical and technical. Not much time remained for Lenard’s attack and the debate that would ensue. The entire arrangement was made to prevent any dramatic effects.

Questions of principle were not touched upon in the long reports, which were full of mathematical formulæ. Then Lenard took the floor for a short talk in which he attacked Einstein’s
theory, but without introducing any emotional coloring. His argument was neither that the theory was inconsistent with experimental results, nor that it contained logical contradictions, but actually only that it was incompatible with the manner in which ordinary “common sense” conceived things. Fundamentally it was only a criticism of a language that was not that of mechanistic physics.

Einstein replied very briefly and then two others spoke still more briefly for and against Einstein. With this the session came to an end. Planck was able to heave a sigh of relief that the meeting had passed without any major conflict. The armed policemen who had watched the building were withdrawn. Planck was in such good humor that he ended the session with one of the trivial jokes that have been current among non-physicists: “Since the relativity theory unfortunately has not yet made it possible to extend the absolute time interval that is available for the meeting, our session must be adjourned.”

To a certain degree the lack of understanding of the philosophical significance of Einstein’s theory among most professional physicists stood in the way of a real debate in which it would have been possible to explain the true content of the theory to its well-meaning opponents. As a result, however, the impression was created that while the Einstein theory might have a meaning for mathematicians, yet for a more philosophically thinking mind it contained various absurdities.

Thus Lenard himself received the impression that not enough attention was paid to his arguments, and the mass of physicists and mathematicians had no opportunity to take part in a truly fundamental discussion on a grand scale. For the moment the physicists probably felt relieved that nothing worse had happened; nevertheless, the opportunity had been permitted to pass without organizing a real explanation for the great mass of scientists and educated persons.

The opposition of Lenard and his supporters to Einstein’s theory was checked by one fact. Even though the foundations of the theory could be characterized as “absurd” and “muddled,” yet it was undeniable that inferences could be drawn from this “absurd” theory that every scientist had to admit were usable and important. Even the most vigorous opponent, if he was a physicist or chemist, had to reckon with the formula that represented the relation between mass and energy. If the energy
E
is given off, this is equivalent to a loss of mass
E/c
²
, where
c
is the velocity of light (see
Chapter III
). Even the most zealous
adherent of the “revolution from the Right” had to use this formula
E
=
mc
²
if he wanted to penetrate the nucleus of the atom. Consequently Lenard and his group endeavored to separate this law from its connection with Einstein’s theory and to prove that it had already been known before Einstein, having been advanced by a physicist of whose racial origin and sentiments they approved.

In the writings of those who want to avoid the name of Einstein at any price, the law of the transformation of mass into energy is often to be found as the “principle of Hasenöhrl.” It is interesting, perhaps, for an understanding of the entire milieu in which Einstein worked to describe how this deliberate removal of Einstein’s name occurred.

It had long been known that light falling on a surface exerts a pressure on it as if particles were being hurled against the surface. In 1904 the Austrian physicist Hasenöhrl had concluded from this knowledge: if light radiation is enclosed in a vessel, it will exert a pressure on the walls. Even if the vessel itself does not have any material mass, yet because of the pressure of the enclosed radiation it would under the impact of a force behave like a body with material mass. And this “apparent” mass is proportional to the enclosed energy. When the vessel radiates energy
E
the “apparent” mass
m
will decrease, according to
E
=
mc
²
.

This principle is obviously a special case of Einstein’s law. If radiation is already contained in a body, its mass will decrease when the radiation is given off. Einstein’s law, however, is much more general. He says that the mass of a body, no matter what its nature, decreases if the body loses energy in any manner whatsoever.

Lenard and his group, however, were seeking a substitute for the name Einstein. There were several external factors that favored the choice of Hasenöhrl’s name. During the World War he had fought in the Austrian army — that is, on Germany’s side — and was killed in battle at the age of forty. He thus appeared to be an ideal figure in the view of Einstein’s enemies, a hero and model for German youth who was the very antithesis of the abstract speculator and international pacifist Einstein. Actually, Hasenöhrl was a honest and competent scientist and a sincere admirer of Einstein.

The legend originated with Lenard’s book
Great Men of Science
. The author presented a series of biographies of great men, such as Galileo, Kepler, Newton, Faraday, and others,
and he concluded with one of Hasenöhrl. In order to link him with the preceding heroes Lenard said of him: “He loved music and his violin as Galileo his lute: he was very fond of his family and as extremely modest as Kepler.” Further on he says about Hasenöhrl’s conclusions: “The applications of this idea have already progressed very far today, although almost entirely in the names of other people.” “Other people” apparently means Einstein.

The vicious attacks on Einstein resulted in arousing interest in his theories among all classes of people in every country. Theories that were of no great significance to the masses and at that almost incomprehensible to them became the center of political controversies. At a time when political ideals had been shattered by the war and new philosophies and political systems were being sought, the public was puzzled and mysteriously attracted by the connection between Einstein’s scientific work and politics. The public interest was further increased by the appearance of articles by philosophers published in daily newspapers stating that Einstein’s theories might perhaps be of some importance in physics, but were certainly untrue philosophically.

The public wondered what sort of man was this Einstein, and they wanted to see and hear this famous scientist in person. From every country Einstein began to receive invitations to come and give lectures. He was amazed, but happy to comply with the people’s wishes. He enjoyed leaving the narrow circle of his professional colleagues and coming into contact with new people. It was also refreshing for him to leave Berlin and Germany, to go away from this tormented and harrowing atmosphere, and to see new countries.

These journeys and public appearances, however, added another cause for attacks on Einstein. Even some German scientists became annoyed, and one of them, a hard-working observer in the laboratory, wrote a brochure entitled
The Mass Suggestion of the Relativity Theory
. In it he gave an interpretation of Einstein’s travels from his own point of view. He wrote: “As soon as the erroneous character of the relativity theory became evident in scientific circles, Einstein turned more and more to
the masses and exhibited himself and his theory as publicly as possible.”

The first instance of this “unscientific” publicity was Einstein’s lecture at the ancient and honorable University of Leiden in Holland. There he lectured before fourteen hundred students of this famous center of physical science on “Ether and the Relativity Theory.” This lecture led to many misinterpretations. Einstein, who had previously suggested that the term “ether” be dropped so as to prevent the rise of any idea that one is dealing with a material medium, discussed another proposal: namely, the word “ether” be used for “curved space,” or what amounts to the same thing, for the gravitational field present in space.

Einstein’s new proposal irritated some physicists and made others happy. Quite a few were unable to differentiate between a proposal to use a word in a certain sense and an assertion of a physical fact. They said: “For a long time efforts were made to convince us of the sensational fact that the ether had been got rid of, and now Einstein himself reintroduces it; this man is not to be taken seriously, he contradicts himself constantly.”

Einstein, however, was happy to be in the quiet, pleasant city of Leiden, among good friends and remote from the controversies of Berlin. He loved to carry on discussions with a physicist of this city, Paul Ehrenfest, a Viennese by birth who was married to a Russian physicist. Husband and wife were indefatigably ready to discuss with Einstein the most subtle questions regarding the logical relations of physical propositions.

Einstein was also appointed professor at Leiden, but he was required to lecture there only a few weeks throughout the year. It was a pleasant thought to look forward to this period of rest every year. And in Berlin there were constant speculations as to whether Einstein would move permanently to Holland. His opponents tried everything possible to make it unpleasant for him to remain in Berlin. Many Germans thought that they must be thankful to Einstein because by means of his great popularity abroad he was acting to increase Germany’s prestige after the lost war. His enemies, however, began a campaign against him, asserting that he was making propaganda abroad only for his own reputation, not for Germany.

Hänisch, the Prussian Minister of Education and a member of the Social Democratic Party, wrote an anxious letter to Einstein entreating him not to let himself be disturbed by these attacks and to remain in Germany. The government of the German
Republic was very well aware how valuable he was for German culture and for its prestige throughout the world. The German government was even sorry that the great new theory of a German scientist had been studied and confirmed by English astronomers so that a large part of the ensuing fame had been lost to the Germans. The Minister requested Einstein to make use of the assistance of German observers and promised him governmental assistance.

Einstein, who appreciated greatly the significance of Berlin as a center of science and research, also understood very well that it was now important for all progressively minded elements to do everything possible to increase the prestige of the German Republic. He wrote a letter to the Minister in which he said: “Berlin is the place to which I am bound by the closest human and scientific ties.” He promised if possible to remain in Berlin and even applied for German citizenship, something that he had not wanted to accept from the Imperial government. He thus became a German citizen, a circumstance that later entailed only troubles for him.

In Prague, which was now the capital of the new Czechoslovak Republic, a Urania society had been organized to arrange lectures for the German-speaking population, and in particular to acquaint them with the great personalities of the new republican Germany. The president of Urania, Dr. O. Frankel, also endeavored to induce Einstein to lecture in Prague. Einstein, who was fond of recalling the quiet times he had enjoyed when he was working in Prague, seized the opportunity to revisit his old university and friends. He was also interested in becoming acquainted with the new democratic state that had arisen under the leadership of President Masaryk on the ruins of the Habsburg monarchy. The psychological status of the German minority in Prague and in Czechoslovakia in general was approximately like that of the population of the defeated German Reich within Europe. Einstein’s visit increased the self-esteem of the Germans in Czechoslovakia, who were later called “Sudeten Germans,” and played a fateful role in the crisis that led to the second World War. When Einstein’s visit was announced, one of the papers of this minority wrote: “The
whole world will now see that a race that has produced a man like Einstein, the Sudeten German race, will never be suppressed.” This was characteristic of the nationalistic thinking. On the one hand every effort was made to keep the race free of all foreign admixtures; on the other hand, when someone was needed, even one who had not spent two years among this race was counted as a member of the group.

Early in 1921 Einstein returned to Prague, where I was then teaching as his successor. I had not seen him for years. I remembered only the great physicist, the man with an artistic and often jesting outlook on the world, who at that time had already enjoyed a great reputation among scientists. But during the years that had passed since then, he had become an international celebrity, a man whom everyone recognized from his photographs in the newspapers, whose opinions on politics and art were sought by every reporter, and whose autograph was wanted by every collector; in short, a man whose life no longer belonged entirely to himself. As so often happens in such cases, he had ceased to be an individual person in many respects; he had now become a symbol or banner upon which the gaze of masses of people was directed.

I was therefore very curious to meet him again, and was somewhat worried about how I could make it possible for him to live a halfway quiet life in Prague and prevent him from being overburdened by his obligations as a famous man. When I met him at the station, he had changed very little and still looked like an itinerant violin virtuoso, with the combination of childlikeness and self-assurance that attracted people to him, but that sometimes also offended them. I had been married only a short time then, and during this period shortly after the war it was so difficult to find an apartment that I lived with my wife in my office at the Physics Laboratory. It was the same room, with the many large windows looking out on the garden of the mental hospital, that had formerly been Einstein’s office. Since Einstein would have been exposed to curiosity-seekers in a hotel, I suggested that he spend the night in this room on a sofa. This was probably not good enough for such a famous man, but it suited his liking for simple living habits and situations that contravened social conventions. We told no one about this arrangement, and no journalist or anyone else knew where Einstein spent the night. My wife and I spent the night in another room. In the morning I came to Einstein and asked him how he had
slept. He replied: “I felt as if I were in a church. It is a remarkable feeling to awake in such a peaceful room.”