- The Dilemmas of an Upright Man: Max Planck as Spokesman for German Science by J.L. Heilbron
California, 250 pp, £14.50, July 1986, ISBN 0 520 05710 4
The dilemmas referred to in the title of this book were those faced by a leading German scientist who believed in his country right or wrong even when that country became the embodiment of evil. Max Planck is famous to this day for his introduction of the quantum theory. He was born in 1858 in Kiel, which was then part of Denmark. One of his formative memories was the triumphant entry in 1864 of Bismarck’s Prussian troops, which recovered the province of Schleswig-Holstein and united it with Prussia. His elder brother’s death in the Franco-Prussian War of 1870/71 ‘made him feel at one with the heroes who sealed their true love for the fatherland with their own blood’. They were noble sentiments in those days. At school in Munich – his father was a professor of law at the University – he nearly always earned the annual prize for religion and good behaviour. His teachers described him as conscientious, open, cheerful, gifted in all subjects, especially mathematics, yet modest and popular with his classmates. He was also intensely musical and had absolute pitch. He wondered whether to study Classics, music or physics and finally opted for the latter, even though a leading physicist advised him that there was nothing significant left to be discovered in that subject. Planck found nothing to rebel against until he was over forty when the dogged pursuit of a vital physical problem led him, almost against his will, to make a revolutionary discovery.
Until then he wrote treatises on the physics of heat, first as a Privatdozent (unpaid) in Munich, later as professor in Kiel and finally in Berlin. They aroused little interest. His appointment at Kiel was given in the confidence ‘that he would remain faithful in unbreakable loyalty to His Majesty the Emperor and to the Imperial Family’. To Planck that read, not as an empty phrase, but as a sacred duty to which he still felt bound 33 years later, after the collapse of the German Armies in October 1918. He then wrote to Einstein: ‘it would be a great stroke of fortune for us, indeed a saving grace, if the bearer of the crown would voluntarily renounce his rights. But the word “voluntary” makes it impossible for me to come forward in the matter; for first I think of my sworn oath, and second, I feel something that you will never understand at all ... namely, piety and an unbreakable attachment to the state to which I belong and which is embodied in the person of the monarch.’ Two days afterwards the Reichstag declared a parliamentary republic and Germany was thrown into chaos.
Planck’s epoch-making discovery, made in 1900, was concerned with the interaction between radiation and matter. The question that exercised German physicists concerned the colour and intensity of radiation emitted by a hot black body. The experimentalists had developed sensitive methods for measuring the radiation, and a theoretician, Wilhelm Wien, had derived an apparently well-founded mathematical theory to account for their observations. However, as techniques were refined and temperatures raised, deviations from Wien’s formula became apparent and Planck modified the formula in a way that fitted the observations exactly. A lesser man would have been content with that, but Planck had already been struggling unsuccessfully for six years with the formulation of a fundamental law for the interaction between radiation and matter: he now felt that ‘his formula had only limited value’ since even if it proved accurate, it was only ‘happily guessed’. ‘From the day of its formulation,’ he wrote, ‘I was occupied with the problem of obtaining for it a true physical meaning. Then, after several weeks of the most strenuous work of my life, the darkness lifted, and a new unexpected perspective began to dawn on me.’