OCTOBER 1949

SCIENTIFIC AMERICAN

VOL. 181, NO. 4

VISIT TO DUBLIN In which a noted theoretical physicist calls upon

the remarkable little group of eminent scientists

at Ireland's exotic Institute for Advanced Studies

By my watch, the plane landed at noon. A hostess with red hair and

green eyes, in a shamrock-green uniform, announced in a sweet Irish brogue: "You are in Shannon, Ireland. It is now 4:55 p.m. local time. All passengers are re­quested to leave."

My first contact with Europe after 13 years looked good to me. The immigra­tion officer at the airport asked why I had come to Ireland. I told him I had been invited to lecture at Dublin's Insti­tute for Advanced Studies. At once the officer became very friendly and began to talk about the Institute. I was in a country where the title of Professor is a badge of honor, not of failure.· Even the customs officers were lwlpful. I had been warned that they were terrors, that they minutely examine one piece of lug­gage after another, especially anxious to discover nylon stockings. I found them like all Irishmen: they love to philoso­phize and they are never in a hurry. It is a country where leisure as well as scholarship is appreciated.

Outside the splendid Shannon airport a rickety, almost disintegrating bus was waiting. It had a conductor, driver and two passengers. They all fell into a long discussion for my benefit about the rela­tive merits of the town's two hotels. Since they could not agree among them­selves, I decided for the nearest. It had a wonderful garden and the air smelled of spring and flowers. (I wish someone would explain why the smell of the Eu­ropean air is so different from the Ameri­can; I have never heard a hypothesis to account for this phenomenon of nature, but everyone who has visited both con­tinents agrees that it is a' fact.)

Next morning I was on my way to Dublin by a train that was a cross be-

by Leopold Infeld

tween a U. S. streamliner and my son's toy. At Dublin my friend, Professor John Lighton Synge, met me at the station. He once taught at the UniverSity of Toronto, where for years we disagreed about al­most every subject we discussed, and en­joyed it immensely. Last year he chose to return to his native Ireland from America, where he was rightly esteemed as a distinguished applied mathemati­cian, when he was offered a senior pro-

CLASSICAL ENTRANCE is inside the School of Cosmic Physics, housed in one of Institute's two bnildings.

fessorship at the Institute for Advanced Studies.

Dublin, upon which I was setting eyes for the first time, looked to me just as I had expected it to, only more so. I was starved for an old town, for aged scen­ery. I found Dublin enchanting. Its buildings are simple and austere; against this serious architectural background the Dubliners appear doubly gay and vivid. I experienced the long-missed pleasure of walking through streets charged with long and violent memories.

On opposite sides of Merrion Square stand the two buildings of the Institute, one the School of Theoretical Physics, the other the School of Cosmic Physics. Each School has three senior professors; those in the School of Theoretical Phys­sics, in order of seniority, are: Erwin Schrodinger, Walter Heitler and Synge. The Institute, which draws students from all parts of the earth, has put the name of Ireland on the world map of scientific achievement. Yet its influence upon its own country, upon Irish intel­lectlfal life and universities, is small. In its cloistered isolation the Institute is a

miniature of Ireland itself, whose prob­lems and fights as a nation are not those of the rest of the world.

I was tense because of my approach­ing lecture. I had not often spoken to such a distinguished audience as I was about to face. The subject I had chosen was a highly specialized one: some rc­cent work on the general theory of rela­tivity which I had done with Albert Einstein. It dealt with a problem that we had first tackled 12 years ago but had been solved only in the last few months.

The problem has to do with the mo­tions of double stars (see page 42).

II

© 1949 SCIENTIFIC AMERICAN, INC

PRINCIP AL OCCUPANTS of the Institute are shown in this group portrait. At the far right is author Infeld. At the far left is \Valter Heitler, best known for his work

in. applying thc quantum theory to chcmistry. Second from the left is John Lighton Synge, a notcd applicd mathematician. Third is Erwin Sclll"odingcr, originator

Imagine two stars of comparable mass moving around each other in space. We have no direct, precise observations to guide us as to the relative motions in such a system, for in our own solar sys­tem the masses of the revolving planets are small compared with that of the sun. The motions of double stars have been worked out theoretically on the basis of classical Newtonian mechanics. But what is the answer of relativity theory, which describes the phenomena of gravi­tation better, more deeply and with greater logical simplicity than does clas­sical theory? Paradoxically, the very fact that the general relativity theory is logi­cally simpler makes the problem of de­ducing the laws of motion much more difficult in relativity theory than in New­tonian theory. The reason is that in rt:;!ativity theory we assume much less than in classical mechanics; consequent­ly we must deduce much more. It is this task of deducing laws of motion from the laws of the gravitational field that has proved to be difficult.

We believe, however,' that we have now derived correctly the laws of mo­tion of a double star, and that we know

12

how the true motions differ from those predicted by the old Newtonian laws. And we believe, too, that the laws can­not be refined much beyond the form in which we have deduced them.

IT would be difficult to imagine any

place in the world where a better audience for such a lecture could be found than at the Dublin Institute. The often-heard saying that only 12 people understand relativity theory is utterly stupid. Every modern theoretical phys­icist understands it. But it is true that relativity theory is not today the center of interest among theoretical physicists; the focus of modern research is nuclear theory and quantum electrodynamics. Few physicists in recent years have done any creative work in relativity. But among those few are two of the three senior professors at Dublirt-Schrodinger and Synge. These men are justly recog­nized as two of the best specialists in this field.

When I presented myself at the simple but dignified offices of the Institute on the morning of the lecture, I learned that Eamon de Valera had just tele-

phoned that he intended to come to it. A few minutes before my lecture I met de Valera in Synge's office. His face looks even more ascetic than in his photo­graphs, and the impression of strength through asceticism was heightened by a dark suit and tie. (I was told that he always dresses in black.) In private con­versation he speaks softly. He did not appear at all out of place in the calm surroundings of the Institute; he could easily have been mistaken for one of the senior professors, except for the fact that he conducted himself in its halls with the subdued awe that most people re­serve for church. Indeed, he is verv proud of the Institute; it was his ide� and his creation. Now that he is only the leader of the opposition in Ireland, the Institute remains, along with the inde­pendence of his country, as one of the few deeds of his life that the government cannot change.

We went together to the small lecture room, and I found with great pleasure that the room was crowded. (Like most lecturers, I do not much care whether the audience is small or large, as long as the lecture room is filled.) It was espe-

© 1949 SCIENTIFIC AMERICAN, INC

of wave mechanics and author of the famous hook What Is Life? FOluth is L. Janossy, an outstanding inves­tigator of cosmic rays. Not shown is L. W. Pollak, a dis-

tingnished meteorologist and director of School of Cos­mic Physics. All thcse men with exception of Pollak and Janossy work in the School of Theoretical Physics.

cially pleasing to have a vivid one-hour discussion later, and an hour's discussion again the next day. My distinguished audience helped me in the understand­ing of my own lecture.

I was especially happy that my stay in Dublin gave me the opportunity to talk with Schrodinger and Heitler. Schrodinger, a Viennese brought up in the great tradition of the Austrian physicist Ludwig Boltzmann, is known as the originator of wave mechanics. His name is linked with those of Germany's Werner Heisenberg and Great Britain's P. A. M. Dirac; the trio were jointly awarded the Nobel prize in 1933 as the creators of quantum mechanics. Dirac and Heisenberg were younger than Schrodinger when they wrote their great papers. They are now in their late 40s, Schrodinger in his early 60s. Theoretical physics, more than most sciences, is a young man's game; the greatest achieve­ments in it usually come while the imagi­nation is still youthful and unfettered. Schrodinger has done much first-class work since 1928, but none of it of such a revolutionary character as that in the years 1925-28. The same thing can be

said, though perhaps to a lesser degree, about Heisenberg and Dirac.

SCHRODINGER is not only a great scientist; he is a most interesting and

charming man-intelligent, witty, eru­dite. He admires Spinoza and good litera­ture, and is himself an excellent writer. I saw him for the first time when he lec­tured, with spirit and artistry, in the Berlin of 1928. He was then at the peak of his fame; he occupied Max Planck's chair in theoretical physics, the greatest scientific honor in Germany. I saw him again in 1934 in Cambridge, England, when, on a Rockefeller Fellowship, I was working on the unitary field theory with Max Born, who had just left Nazi Germany. On Schrodinger's invitation, I went to visit him at Oxford and spent a delightful evening in his home. He was interested in the unitary field theory, and wrote an important, original paper on the subject. The distinctive mark of Schrodinger's genius has always been the originality of his thinking, his self-con­fidence and disregard for tradition. He showed a lack of political judgment, however, when he left Oxford to return

to Austria in 1936. He escaped, after Hitler entered Vienna, only by a dra­matic Hight to Switzerland. From there he went to Dublin on de Valera's invi­tation to become the first professor at the Institute for Advanced Studies.

The Dublin Institute arranges public lectures from time to time. In 1943, Schrodinger gave a series of colorful lectures which appeared five years later in book form under the title: What .ls Life? Startling titles must disappoint anyone who looks in books for an answer to'unanswerable questions. Schrodinger's book is not an exception to this rule. It deals vividly and intelligently, however, with questions that lie on the borderline between physics and biology-a field which many people believe will form the center of future research. Schrodin­ger says: " . . . living matter, while not eluding the 'laws of physics' as estab­lished up to date, is likely to involve 'other laws of physics' hitherto unknown, which, however, once they have been revealed, will form just as integral a part of this science as the former. . . . "

SclU'odinger points out that the archi­tecture of a gene, that is, the manner in

13

© 1949 SCIENTIFIC AMERICAN, INC

which atoms are put together to create the big molecules that form a living organism, is today unknown. It is, as the science writers love to say, a mys­tery-a word which curiously is most often used in the popularization of that most rational subject, physics. In con­trast to a crystal, which represents a design that repeats itself, the big mole­cules that form the living organism are like an artistically woven tapestry; it is the design of the entire tapestry that matters, not the mere repetition of a theme.

At the molecular level in phYSics dis­order and chaos reign. In the macroscopic world of our measm'ements-the world of pendula, steam engines, electric cur­rents-all is order. Gas obeys the laws that have been confirmed by our meas­urements because it is composed of a tre­mendous number of molecules, and the laws are based on averages. Order emerges' in our macrophysical world from the disorder in the microphysical world through the laws of statistics ap­plied to many disorderly individuals. But these laws collapse and become mean­ingless if there are only a few molecules in the gas container. Only when it be­comes colder and colder, when the tem­perature approaches absolute zero, only then does order reign among the mole­cules. It is the order of death; molecules that do not move cannot be disorderly.

Yet the living process somehow defies the rules; it organizes a group of mole­cules into a high degree of order. A big molecule, a single group of atoms, pro­duces orderly events. It multiplies itself, forming an organism that lives. Even in a complicated organism, the number of such molecules is amazingly small. One cubic inch of air contains a million times more molecules than a grown-up mam­mal. The mechanism that governs an organism which is composed of not too great a number of molecules is not the statistical probability mechanism of or­dinary physics. We shall understand the laws of living organisms only when we understand the transition order-from­order which seems to reign in biology, just as the transition order-from-disorder reigns in physics.

Schrodinger's book is not easy; it deals with difficult problems which will chal­lenge science for a long time to come. The fact that his lectures were attended by overflowing audiences speaks well for the Dubliners.

In Dublin everyone had time to talk; no one rushed. We could and did discuss everything and nothing. And indeed it was a great relief to be back in a part of the world that appreciates leisure. Eu­rope is a lazy man's world, which has its advantages. I learned in North America how not to be lazy-and received ulcers as a reward.'

On the last day of my stay in Dublin, I visited the Institute's School of Cosmic

14

Physics. Its director, L. W. Pollak, is a famous meteorologist. He is small, plumpish, bald and vivacious, and he talks with the ease of those who have sharpened their tongues in Continental cafes. He showed me a neatly furnished drawing room which he maintains as a shrine; from this room de Valera directed the 1916 revolt. Pollak was a professor at the German university in Prague in the 1930s, but had the foreSight to leave that city just before Hitler entered it. As early as 1926, he had had the idea of introducing a punched-card system into geophysics in general and climatology in particular. He organized a climatologi­cal network in Czechoslovakia. His punched cards were sorted and tabu­lated by machines in Prague's statistical office. This system has now been adopted all over the world. And his dream suggestion for the creation of a world weather office is now a reality. The U. S. Weather Bureau in vVashing­ton has more than 70 million punched cards of all meteorological elements from every place in the world where observa­tions are made. The Bureau's machines quickly digest experiences and store up information. Thus they help to predict the meteorological future by analysis of the past. A book by Pollak and V. Con­rad, giving an account of this wartime development, is to be published by the Harvard University Press this fall.

The Dublin Institute School of Cosmic Physics owes its existence to a short memorandum that Pollak submitted to de Valera on St. Patrick's Day, 1943. Like other professors of the Institute, Pollak speaks of deValera with great admiration. All of them feel that de Valera cared about science and scholar­ship in Ireland.

I TALKED with another senior pro­fessor at the School of Cosmic Physics

-the cosmic-ray investigator L. JfIl10SSY. A Hungarian, with untidy black hair and tense face, he is the youngest permanent member of the Institute. Recently his large volume on cosmic radiation ap­peared; he complained ruefully that it was already antiquated. So rapid is the advancement in this branch of science that a book cannot remain modern dur­ing the usual time-interval between writing and printing. Indeed, the field of cosmic rays is the most fluid field of physics, and every issue of the physics journals brings important contributions, new experimental results, new specula­tions about the origin of these rays. This is one of the subjects that has changed our picture of the elementary bricks of matter, and we are trying now to imi­tate the laboratory of our universe by building apparatus that will produce particles with energies of the same order as those observed in cosmic rays.

Janossy had come to Dublin from Manchester University, one of the very

best places for work on cosmic rays. When I later went to England and visited Manchester, the physicist P. M. S. Blackett showed me its equipment and talked about some of the problems being investigated in cosmic radiation. J {lI1ossy and his collaborators had investigated especially the so-called penetrating showers of mesons created by cosmic rays. The problem of the penetrating showers has also been treated theoreti­cally by Heitler and his group at the Institute. It is an interesting example of successful collaboration between theory and experiment.

How are these mesons produced? One can simplify the present picture as fol­lows: The father of the mesons is a heavy, fast-moving neutron or proton, winging toward the earth from outer space. The mother is the nucleus of an atom in the atmosphere with which the father collides. The mother itself con­sists of many protons and neutrons. Therefore the fast father suffers ( or rather enjoys) many independent colli­sions inside the nucleus. We may im­prove the comparison by saying that the fast particle is like a father running quickly through a harem. The mesons are the offspring of these activities. This general picture, I was told by Janossy, is strongly confirmed by photographs from Manchester and the UniverSity of Bristol.

After my talk with Janossy and Heitler, I came back to the Theoretical Physics Building. Professor Synge ar­ranged an additional hour of discussion on my lecture. I was pleased to see-it was Saturday morning-that many of my listeners had returned, and again I profited much from the spirited remarks of Schrodinger, Heitler and Synge. In­deed, the discussion became so en­grossing that I almost missed my plane to London.

As I left Ireland, I felt strongly how easily one can become attached to this small and beautiful country. I believe also I understood the reasons for it. Ire­land is untouched by war or fears of war. The rest of the world seems far awav from Dublin. It is this isolation, beSide's the beauty of the place and the charm of the Irish, that enchants a visitor. There is an inner desire in many sci­entists for such a refuge. Every scholar longs to be in a place like Oxford, Cam­bridge or Dublin which seems to be outside the world of trivial realities. In isolated Ireland, the Dublin Institute for Advanced Studies with its scholars, most of them fugitives from oppression, seems to be the most peaceful spot on e�1l'th. Can its isolation last for long?

•

Leopold Infeld is professor of. ap­plied mathematics at the University of Toronto and author, with Albert Einstein, of The Evolution of Physics.

© 1949 SCIENTIFIC AMERICAN, INC

DUNS INK OBSERVATORY, at Dunsink in Duhlin County, is thc astronomical section of the School of Cos-

SCHOOL OF THEORETICAL PHYSICS stands on Duhlin's Men-ion Square. Across the square is the huild-

mic Physics_ The dome at the right houses a refractor. Atop main huilding at left is a smaller telescope.

ing of the School of Cosmic Physics. From the lattcr huilding Eamon de Valera directed the revolt of 1916.

15

© 1949 SCIENTIFIC AMERICAN, INC