Quantum_ Einstein, Bohr and the Great Debate About the Nature of Reality - Manjit Kumar [70]
Einstein continued to be troubled by the fact that his theory could not predict either the time or the direction in which the light-quantum emitted as an electron jumps from one energy level to a lower one. 'Nevertheless,' he had written in 1916, 'I fully trust in the reliability of the road taken.'64 He believed it was a road that would eventually lead to a restoration of causality. In his lecture, Bohr argued that no exact determination of time and direction was ever possible. The two men found themselves on opposite sides. In the days that followed, each tried to convert the other to his point of view as they walked the streets of Berlin together or dined at Einstein's home.
'Seldom in my life has a person given me such pleasure by his mere presence as you have', Einstein wrote to Bohr soon after he returned to Copenhagen. 'I am now studying your great publications and – unless I happen to get stuck somewhere – have the pleasure of seeing before me your cheerful boyish face, smiling and explaining.'65 The Dane had made a deep and lasting impression. 'Bohr was here, and I am just as enamoured of him as you are', Einstein told Paul Ehrenfest a few days later. 'He is like a sensitive child and walks about this world in a kind of hypnosis.'66 Bohr was equally intent in trying to convey, in his less than polished German, what it meant to him to have met Einstein: 'It was to me one of my greatest experiences to have met you and to talk to you. You cannot imagine what a great inspiration it was for me to hear your views from you in person.'67 Bohr did so again quite soon, as Einstein made a fleeting visit as he stopped off in Copenhagen in August on his way back from a trip to Norway.
'He is a highly gifted and excellent man', Einstein wrote to Lorentz after seeing Bohr.68 'It is a good omen for physics that prominent physicists are mostly also splendid people.' Einstein had become the target of two men who were not. Philipp Lenard, whose experimental work on the photoelectric effect Einstein had used in 1905 in support of his light-quanta, and Johannes Stark, the discoverer of the splitting of spectral lines by an electric field, had become rabid anti-Semites. The two Nobel laureates were behind an organisation calling itself the Working Group of German Scientists for the Preservation of Pure Science, whose prime aim was to denounce Einstein and relativity.69 On 24 August 1920 the group held a meeting at Berlin's Philharmonic Hall and attacked relativity as 'Jewish physics' and its creator as both a plagiarist and a charlatan. Not to be intimidated, Einstein went along with Walther Nernst and watched the proceedings from a private box as he was vilified. Refusing to rise to the bait, he said nothing.
Nernst, Heinrich Rubens and Max von Laue wrote to the newspapers defending Einstein against the outrageous charges levelled at him. Many of his friends and colleagues were therefore dismayed when Einstein wrote an article for the Berliner Tageblatt entitled 'My Reply'. He pointed out that had he not been Jewish and an internationalist he would not have been denounced, nor his work attacked. Einstein immediately regretted having been riled into writing the article. 'Everyone has to sacrifice at the altar of stupidity from time to time, to please the Deity and the human race', he wrote to the physicist Max Born and his wife.70 He was well aware that his celebrity status meant that 'like a man in the fairy tale who turned everything into gold – so with me everything turns into a fuss in the newspapers'.71 Soon there were rumours that Einstein might leave the country, but he chose to stay in Berlin, 'the place to which I am most closely tied by human and scientific connections'.72
In the two years after their meetings in Berlin and Copenhagen, Einstein and Bohr continued