Max Planck, one of the most important physicists of the 20th century, is widely known as the originator of the quantum theory. He received the Nobel Prize in Physics in 1918 for the quantum theory of radiation, which revolutionized the understanding of the subatomic world. He also made significant contributions to various fields of science such as optics, physical chemistry, thermodynamics and statistical mechanics.
Planck was born on April 23, 1858, in Kiel, Germany, as the son of Johann Julius Wilhelm and Emma von Planck. His father was a professor of law. Planck began his elementary schooling in Kiel. When he was nine the family moved to Munich, where he attended the renowned Maximilian Gymnasium. Although he had a great love for music, his intense hankering was to know about what was absolute and fundamental; thus he devoted himself to science. He writes in his scientific autobiography, “that the outside world is something independent from man, something absolute, and the quest for the laws which apply to this absolute appeared to me as the most sublime scientific pursuit in life.” The first instance of an absolute in nature that deeply impressed Planck was the law of the conservation of energy, taught in a very amusing way by his mathematics teacher, Hermann Müller.
After graduating from the gymnasium, Planck studied at the Universities of Munich and Berlin – where his teachers included Kirchhoff and Helmholtz – and received his doctorate of philosophy at Munich in 1879. In 1885, the University of Kiel appointed him as an associate professor of theoretical physics, were he continued to pursue work on heat theory and on Rudolph Clausius’ ideas about entropy and their applications in physical chemistry. In 1889, he was appointed at the University of Berlin where he remained until his retirement in 1926. Later he became President of the Kaiser Wilhelm Society for the Promotion of Science, a post he held until 1937.
Although his doctoral thesis on thermodynamics was not particularly well received, he was firmly determined to continue his studies of entropy, the most important property of physical systems. His research eventually led to his quantum theory formulations, now known as Planck’s radiation law and Planck’s constant (symbolized by h), thus opening up a new era in natural science.
He was revered by his colleagues not only for the importance of his discoveries but for his great personal qualities. He was a devoted family man, a skilled lecturer, a talented musician, a tireless mountaineer, a formidable administrator, and an inspiration for all. As expressed by Max Born, “to be near Planck is a joy.” According to Einstein, Planck’s intellectual strength and integrity grew from an “emotional condition . . . more like that of a deeply religious man or a man in love.” He had been raised an observant Lutheran and also won numerous prizes at the gymnasium in religion and deportment. His religious convictions guided him throughout his life, as he faced moments of triumph as well as tragedy. Just before his 80th birthday, Planck became an itinerant preacher. In his general lectures, he often presented the reconcilability of science with religion. In his major book Where Is Science Going? (1932) Planck pointed out: “There can never be any real opposition between religion and science; for the one is the complement of the other. Every serious and reflective person realizes, I think, that the religious element in his nature must be recognized and cultivated if all the powers of the human soul are to act together in perfect balance and harmony. And indeed it was not by accident that the greatest thinkers of all ages were deeply religious souls.” In the scientific world, his writings encouraged the synthesis of rationality and belief. Like many other great thinkers, Planck was convinced that science alone cannot take us to the fundamental or absolute reality. He remarked, “May its (exact science) results be ever so deep and far-reaching, it can never succeed in taking the last step which would take it into the realm of metaphysics. … The real world of metaphysics is not the starting point, but the goal of all scientific endeavor, a beacon winking and showing the way from an inaccessibly remote distance.”