Quantum: Einstein, Bohr and the Great Debate About the Nature of Reality

by Manjit Kumar

  They soon discovered the second part of their son’s plan. He wanted to renounce his German nationality and thereby remove the possibility of ever being called up for military service by the Reich. Too young to do it himself, Einstein needed his father’s consent. Hermann duly gave it and formally applied to the authorities for his son’s release. It was January 1896 before they received official notification that Albert, at the cost of three marks, was no longer a German citizen. For the next five years he was legally stateless until he became a Swiss citizen. A renowned pacifist later in life, once he was granted his new nationality Einstein turned up for his Swiss army medical, on 13 March 1901, the day before his 22nd birthday. Fortunately, he was found unfit for military service because of sweaty flat feet and varicose veins.18 As a teenager back in Munich, it was not the thought of serving in the army that bothered him, but the prospect of donning a grey uniform on behalf of the militarism of the German Reich which he hated.

  ‘The happy months of my sojourn in Italy are my most beautiful memories’ was how Einstein, even after 50 years, recalled his new carefree existence.19 He helped his father and uncle with their electrical business and travelled here and there visiting friends and family. In the spring of 1895 the family moved to Pavia, just south of Milan, where the brothers opened a new factory that lasted little more than a year before it too closed. Although amid the upheaval he worked hard to prepare, Einstein failed the Poly entrance exams. Yet his mathematics and physics results were so impressive that the professor of physics invited him to attend his lectures. It was a tantalising offer, but for once Einstein took some sound advice. He had done so badly in languages, literature and history that the director of the Poly urged him to go back to school for another year and recommended one in Switzerland.

  By the end of October Einstein was in Aarau, a town 30 miles west of Zurich. With its liberal ethos, the Aargau canton school provided a stimulating environment that enabled Einstein to thrive. The experience of boarding with the classics teacher and his family was to leave an indelible mark. Jost Winteler and his wife Pauline encouraged freethinking among their three daughters and four sons, and dinner each evening was always a lively and noisy affair. Before long the Wintelers became surrogate parents and he even referred to them as ‘Papa Winteler’ and ‘Mama Winteler’. Whatever the old Einstein said later about being a lone traveller, the young Einstein needed people who cared about him and he for them. Soon it was September 1896 and exam time. Einstein passed easily and headed to Zurich and the Federal Polytechnikum.20

  ‘A happy man is too satisfied with the present to dwell too much upon the future’, Einstein had written at the start of a short essay called ‘My Future Plans’, during his two-hour French exam. But an inclination for abstract thinking and the lack of practical sense had led him to decide on a future as a teacher of mathematics and physics.21 So it was that Einstein found himself, in October 1896, the youngest of eleven new students entering the Poly’s School for Specialised Teachers in the Mathematical and Science Subjects. He was one of the five seeking to qualify to teach maths and physics. The only woman among them was to be his future wife.

  None of Albert’s friends could understand why he was attracted to Mileva Maric. A Hungarian Serb, she was four years older and a bout of childhood tuberculosis had left her with a slight limp. During the first year they sat through the five compulsory maths courses and mechanics – the single physics course offered. Although he had devoured his little sacred book of geometry in Munich, Einstein was no longer interested in mathematics for its own sake. Hermann Minkowski, his maths professor at the Poly, recalled that Einstein had been a ‘lazy dog’. It was not apathy but a failure to grasp, as Einstein later confessed, ‘that the approach to a more profound knowledge of the basic principles of physics is tied up with the most intricate mathematical methods’.22 It was something he learnt the hard way in the years of research that followed. He regretted not having tried harder to get ‘a sound mathematical education’.23

  Fortunately, Marcel Grossmann, one of the other three besides Einstein and Mileva enrolled on the course, was a better mathematician and more studious than either of them. It would be to Grossmann that Einstein later turned for help as he struggled with the mathematics needed to formulate the general theory of relativity. The two quickly became friends as they talked ‘about anything that might interest young people whose eyes were open’.24 Only a year older, Grossmann must have been an astute judge of character, for he was so impressed by his classmate that he took him home to meet his parents. ‘This Einstein,’ he told them, ‘will one day be a very great man.’25

  It was only by using Grossmann’s excellent set of notes that he passed the intermediate exams in October 1898. In old age, Einstein could barely bring himself to contemplate what might have happened without Grossmann’s help after he began skipping lectures. It had all been so different at the beginning of Heinrich Weber’s physics course, when Einstein looked ‘forward from one of his lectures to the next’.26 Weber, who was in his mid-fifties, could make physics come alive for his students, and Einstein conceded that he lectured on thermodynamics with ‘great mastery’. But he became disenchanted because Weber did not teach Maxwell’s theory of electromagnetism or any of the latest developments. Soon Einstein’s independent streak and contemptuous manner began to alienate his professors. ‘You’re a smart boy’, Weber told him. ‘But you have one great fault: you do not let yourself be told anything.’27

  When the final exams took place in July 1900 he came fourth out of five. Einstein felt coerced by the exams, and they had such a deterring effect upon him that afterwards he found ‘the consideration of any scientific problems distasteful to me for an entire year’.28 Mileva was last, and the only one to fail. It was a bitter blow for the couple who were now affectionately calling each other ‘Johonzel’ (Johnny) and ‘Doxerl’ (Dollie). Another soon followed.

  A future as a schoolteacher no longer appealed to Einstein. Four years in Zurich had given rise to a new ambition. He wanted to be a physicist. The chances of getting a full-time job at a university were slim even for the best students. The first step was an assistant’s position with one of the professors at the Poly. None wanted him and Einstein began searching further afield. ‘Soon I will have honoured all physicists from the North Sea to the Southern tip of Italy with my offer!’ he wrote to Mileva in April 1901 while visiting his parents.29

  One of those honoured was Wilhelm Ostwald, a chemist at the Leipzig University. Einstein wrote to him twice; both letters went unanswered. It must have been distressing for his father to watch his son’s growing despair. Hermann, unknown to Albert then or later, took it upon himself to intervene. ‘Please forgive a father who is so bold as to turn to you, esteemed Herr professor, in the interest of his son’, he wrote to Ostwald.30 ‘All those in position to give a judgement in the matter, praise his talents; in any case, I can assure you that he is extraordinarily studious and diligent and clings with great love to his science.’31 The heartfelt plea went unanswered. Later Ostwald would be the first to nominate Einstein for the Nobel Prize.

  Although anti-Semitism may have played a part, Einstein was convinced that it was Weber’s poor references that were behind his failure to secure an assistantship. As he grew increasingly despondent, a letter from Grossmann held out the possibility of a decent, well-paying job. Grossmann senior had learnt of Einstein’s desperate situation and wanted to help the young man whom his son held in such high regard. He strongly recommended Einstein for the next vacancy that arose to his friend Friedrich Haller, the director of the Swiss Patent Office in Bern. ‘When I found your letter yesterday,’ Einstein wrote to Marcel, ‘I was deeply moved by your devotion and compassion which did not let you forget your old luckless friend.’32 After five years of being stateless, Einstein had recently acquired Swiss citizenship and was certain it would help when applying for the job.

  Maybe his luck had changed at last. He was offered and accepted a temporary
teaching job at the school in Winterthur, a small town less than twenty miles from Zurich. The five or six classes Einstein taught each morning left him free to pursue physics in the afternoon. ‘I cannot tell you how happy I would feel in such a job’, he wrote to Papa Winteler shortly before his time in Winterthur ended. ‘I have completely given up my ambition to get a position at a university, since I see that even as it is, I have enough strength and desire left for scientific endeavour.’33 Soon that strength was put to the test when Mileva announced she was pregnant.

  After failing the Poly exams a second time, Mileva returned to her parents in Hungary to await the arrival of the baby. Einstein took the news of the pregnancy in his stride. He had already entertained thoughts of becoming an insurance clerk and now vowed to find any job, no matter how humble, so that they could marry. When their daughter was born, Einstein was in Bern. He never saw Lieserl. What happened to her, whether she was given up for adoption or died in infancy, remains a mystery.

  In December 1901, Friedrich Haller wrote to Einstein asking him to apply for a vacancy at the Patent Office that was about to be advertised.34 The long search for a permanent job seemed at an end as Einstein sent off his application before Christmas. ‘All the time I rejoice in the fine prospects which are in store for us in the near future’, he wrote to Mileva. ‘Have I already told you how rich we will be in Bern?’35 Convinced that everything would be settled quickly, Einstein quit a year-long tutoring job at a private boarding school in Schaffhausen after only a few months.

  Bern was home to some 60,000 people when Einstein arrived during the first week of February 1902. The medieval elegance of the Old Town quarter had changed little in the 500 years since it had been rebuilt following a fire that destroyed half the city. It was here that Einstein found a room on Gerechtigkeitgasse, not far from the city’s famous bear pit.36 Costing 23 francs a month, it was anything but the ‘large, beautiful room’ he described to Mileva.37 Not long after he unpacked his bags, Einstein went down to the local newspaper to place an advert offering his services as a private tutor of mathematics and physics. It appeared on Wednesday, 5 February and offered a free trial lesson. Within days it paid off. One of the students described his new tutor as ‘about five foot ten, broad-shouldered, slightly stooped, a pale brown skin, a sensuous mouth, black moustache, nose slightly aquiline, radiant brown eyes, a pleasant voice, speaking French correctly but with a slight accent’.38

  A young Romanian Jew, Maurice Solovine, also came across the advert as he read his newspaper walking down the street. A philosophy student at Bern University, Solovine was also interested in physics. Frustrated that a lack of mathematics was preventing him from gaining a deeper understanding of physics, he immediately made his way to the address given in the newspaper. When Solovine rang the bell, Einstein had found a kindred spirit. The student and tutor talked for two hours. They shared many of the same interests and after spending another half hour chatting in the street, they agreed to meet the following day. When they did, all thoughts of a structured lesson were forgotten amid a shared enthusiasm for exploring ideas. ‘As a matter of fact, you don’t have to be tutored in physics’, Einstein told him on the third day.39 What Solovine liked about Einstein, as the two quickly became friends, was the care with which he outlined a topic or problem as lucidly as possible.

  Before long, Solovine suggested that they read a particular book and then discuss it. Having done the same with Max Talmud in Munich as a schoolboy, Einstein thought it an excellent idea. Soon Conrad Habicht joined them. A friend from Einstein’s aborted stint teaching at the boarding school in Schaffhausen, Habicht had moved to Bern to complete a mathematics thesis at the university. United by their enthusiasm for studying and clarifying the problems of physics and philosophy for their own satisfaction, the three men started calling themselves the ‘Akademie Olympia’.

  Even though Einstein came highly recommended by a friend, Haller had to make sure he was capable of doing the job. The ever-growing number of patent applications for all manner of electrical devices had made the hiring of a competent physicist to work alongside his engineers a necessity rather than a favour for a friend. Einstein impressed Haller sufficiently to be provisionally appointed a ‘Technical Expert, Third Class’ with a salary of 3,500 Swiss francs. At eight o’clock in the morning on 23 June 1902, Einstein reported for his first day as a ‘respectable Federal ink pisser’.40

  ‘As a physicist,’ Haller told Einstein, ‘you haven’t a clue about blueprints.’41 Until he could read and assess technical drawings, there would be no permanent contract. Haller took it upon himself to teach Einstein what he needed to know, including the art of expressing himself clearly, concisely, and correctly. Although he had never taken kindly to being instructed as a schoolboy or student, he knew that he needed to learn all he could from Haller, ‘a splendid character and a clever mind’.42 ‘One soon gets used to his rough manner’, Einstein wrote. ‘I hold him in very high regard.’43 As he proved his worth, Haller likewise came to respect his young protégé as a prized member of staff.

  In October 1902, aged only 55, his father fell seriously ill. Einstein travelled to Italy to see him one last time. It was then, as he lay dying, that Hermann gave Albert his permission to marry Mileva – a prospect that he and Pauline had long opposed. With only Solovine and Habicht as witnesses, Einstein and Mileva married the following January in a civil ceremony at the Bern registrar’s office. ‘Marriage is,’ Einstein said later, ‘the unsuccessful attempt to make something lasting out of an incident.’44 But in 1903 he was just happy to have a wife that cooked, cleaned, and simply looked after him.45 Mileva had hoped for more.

  The Patent Office took up 48 hours a week. From Monday to Saturday Einstein started at eight o’clock and worked until noon. Then it was lunch either at home or with a friend at a nearby café. He was back in the office from two until six. It left ‘eight hours for fooling around’ each day, and ‘then there’s also Sunday’, he told Habicht.46 It was September 1904 before Einstein’s ‘provisional’ position was made permanent with a pay rise of 400 francs. By the spring of 1906 Haller was so impressed with Einstein’s ability to ‘tackle technically very difficult patent applications’ that he rated him as ‘one of the valued experts at the office’.47 He was promoted to technical expert, second class.

  ‘I will be grateful to Haller for as long as I live’, Einstein had written to Mileva soon after moving to Bern in the expectation that a job at the Patent Office would sooner or later be his.48 And he was. But it was only much later that he recognised the extent of the influence that Haller and the Patent Office exerted on him: ‘I might not have died, but I would have been intellectually stunted.’49 Haller demanded that every patent application be evaluated rigorously enough to withstand any legal challenge. ‘When you pick up an application, think that anything the inventor says is wrong,’ he advised Einstein, or else ‘you will follow the inventor’s way of thinking, and that will prejudice you. You have to remain critically vigilant.’50 Accidentally, Einstein had found a job that suited his temperament and honed his abilities. The critical vigilance he exercised in assessing an inventor’s hopes and dreams, often on the basis of unreliable drawings and inadequate technical specifications, Einstein brought to bear on the physics that occupied him. The ‘many-sided thinking’ his job entailed he described as a ‘veritable blessing’.51

  ‘He had the gift of seeing a meaning behind inconspicuous, well-known facts which had escaped everyone else’, recalled Einstein’s friend and fellow theoretical physicist Max Born. ‘It was this uncanny insight into the working of nature which distinguished him from all of us, not his mathematical skill.’52 Einstein knew that his mathematical intuition was not strong enough to differentiate what was really basic ‘from the rest of the more or less dispensable erudition’.53 But when it came to physics, his nose was second to none. Einstein said he ‘learned to scent out that which was able to lead to fundamentals and to turn aside from everything else, fr
om the multitude of things which clutter up the mind and divert it from the essential’.54

  His years at the Patent Office only heightened his sense of smell. As with the patents that inventors submitted, Einstein looked for subtle flaws and inconsistencies in the blueprints of the workings of nature put forward by physicists. When he found such a contradiction in a theory, Einstein probed it ceaselessly until it yielded a new insight resulting in its elimination or an alternative where none had existed before. His ‘heuristic’ principle that light behaved in certain instances as if it was made up of a stream of particles, light-quanta, was Einstein’s solution to a contradiction at the very heart of physics.

  Einstein had long accepted that everything was composed of atoms and that these discrete, discontinuous bits of matter possessed energy. The energy of a gas, for example, was the sum total of the energies of the individual atoms of which it was made up. The situation was entirely different when it came to light. According to Maxwell’s theory of electromagnetism, or any wave theory, the energy of a light ray continuously spreads out over an ever-increasing volume like the waves radiating outwards from the point where a stone hits the surface of a pond. Einstein called it a ‘profound formal difference’ and it made him uneasy while stimulating his ‘many-sided thinking’.55 He realised that the dichotomy between the discontinuity of matter and the continuity of electromagnetic waves would dissolve if light was also discontinuous, made up of quanta.56