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Bohr, Niels

Category: Genius

Niels Henrik David Bohr (1885 –1962) was a Danish physicist who made major contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. He predicted the existence of a new zirconium-like element, which was named hafnium and was also a promoter of scientific research. He founded the Institute of Theoretical Physics at the University of Copenhagen, now known as the Niels Bohr Institute, which opened in 1920.

Perhaps his most well known contribution to physics is the model he conceived for the Atom. Today his model still dominates the thinking of many physicists, but it is widely misunderstood. It was a model and was not intended to be a physical representation. If you look at the observations for him, you will see that he conceived of the model in a dream, and then tried to interpret the dream.

His theories were described in three papers, which later became famous as "the Trilogy", published in Philosophical Magazine in July, September and November 1913.

Initially his interpretation of the dream tried to use Rutherford's nuclear structure and Max Planck's quantum theory. His first model of the atom was based on electrons travelling in orbits around the atom's nucleus, with the chemical properties of each element being largely determined by the number of electrons in the outer orbits of its atoms. But whilst the Bohr model worked for hydrogen, it could not explain more complex elements, and by 1919, Bohr was moving away from the idea that electrons orbited the nucleus and his model became far less physical and far more functional.

The great extension of our experience in recent years has brought light to the insufficiency of our simple mechanical conceptions and, as a consequence, has shaken the foundation on which the customary interpretation of observation was based. - "Atomic Physics and the Description of Nature" (1934)

Allied to this move away from the physical to the functional was his principle of 'complementarity': Ultimately what any thing was at any one time was determined by its behaviour – its functions and which functions were active and which were not. Any object could thus at one time functionally appear, for example, as a wave and at another time as a particle. The notion of complementarity dominated his thinking on both science and philosophy.

He became hugely frustrated in later life trying to explain this in such a way that he would be understood. How do you explain a software based theory to people whose only concept of the world is hardware based? – it is impossible without the sort of analogy I have used and "Shortly before his death [Bohr] complained that no professional philosopher had ever understood his doctrine of complementarity."

Why did Bohr and in fact how did Bohr end up in an area that is clearly spiritual, when his early training was scientific?  The key is his interest in philosophy. Bohr read the 19th century Danish philosopher, Søren Kierkegaard, for example. About Stages on Life's Way Bohr wrote, " I do not believe that it would be very easy to find anything better ... I even think it is one of the most delightful things I have ever read."

Bohr also completely rejected his Lutheran father's faith, but may have been influenced by his Jewish mother's beliefs. Bohr resigned his membership in the Lutheran Church on 16 April 1912.

He also appears to have embraced a considerable number of ideas from eastern sources. When King Frederick IX announced that he was conferring the Order of the Elephant on Bohr, for example Bohr designed his own coat of arms which featured a taijitu (symbol of yin and yang) and the motto in Latin: contraria sunt complementa: "opposites are complementary". We also have the following very key quote from him

For a parallel to the lesson of atomic theory regarding the limited applicability of such customary idealizations, we must in fact turn to quite other branches of science, such as psychology, or even to that kind of epistemological problems with which already thinkers like Buddha and Lao Tzu have been confronted, when trying to harmonize our position as spectators and actors in the great drama of existence. [Speech on quantum theory at Celebrazione del Secondo Centenario della Nascita di Luigi Galvani, Bologna, Italy (October 1937)]

So ultimately he sought a solution within the spiritual world.

Where did this inspiration come from? Firstly I think inherited genes played their part. And, far more controversial, looking at him and the shape of his face and head I think he was a victim of a difficult birth.

Like many of his day he had his share of love and grief. He and his future wife Margrethe were married in a civil ceremony at the town hall in Slagelse. They had six sons. The oldest, Christian, died in a boating accident in 1934, and another, Harald, died from childhood meningitis. So here we have the grief. But he also had reason for great joy. The other four children went on to lead successful lives. Aage Bohr became a successful physicist and in 1975, like his father, was awarded the Nobel Prize in physics. His other sons were Hans Henrik, a physician; Erik, a chemical engineer; and Ernest, a lawyer.

But I think that one very specific mechanism was far more influential in his early inspiration. His philosophical researches had taught him to [like Nietzsche] clear your mind of all beliefs in order to receive inspiration.

The first thing Bohr said to me was that it would only then be profitable to work with him if I understood that he was a dilettante. The only way I knew to react to this unexpected statement was with a polite smile of disbelief. But evidently Bohr was serious. He explained how he had to approach every new question from a starting point of total ignorance. It is perhaps better to say that Bohr's strength lay in his formidable intuition and insight rather than erudition” [Abraham Pais, Niels Bohr : His Life and Work as Seen by His Friends and Colleagues (1967) ]

His approach was to believe nothing, but question everything and he also advised others to do the same.

Every sentence I utter must be understood not as an affirmation, but as a question.

His later life was not as productive as his early life, he was involved in the nuclear programmes and became head of a number of worthy institutes, but he was coasting comparatively speaking. He died of heart failure at his home in Carlsberg on 18 November 1962. 

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