Rabindranath Tagore (actual Bengali name: Rabindranath Thakur) (1861–1941), the great Indian philosopher, a Bengali poet and a polymath, who received Nobel Prize for Literature in 1913, lived during a transition period of Indian history in general and the Bengali culture in particular, when physics also went through revolutionary changes. Albert Einstein (1879–1955), the most prominent physicist of the 20th century, was the pioneer of modern physics, who produced theories which advanced physics to unprecedented levels. Although Einstein produced the ‘the principle of photoelectric effect’ for which he received the Nobel Prize for physics in 1921 and which was pivotal to the advent of quantum mechanics, he could not fully reconcile with the multifarious implications of quantum mechanics. The two stalwarts of the first half of the 20th century met a number of times from 1926 onwards. When Tagore visited continental Europe and then America in 1930, they met at least four times in Berlin and New York. The meeting at Einstein’s summer villa outside Berlin was of particular interest when they exchanged views and philosophical ideas extensively. During that meeting – poignantly described by Dmitri Marianoff, a journalist in the New York Times, as being between ‘Tagore, the poet with the head of a thinker, and Einstein, the thinker with the head of a poet’ – the two exchanged views on the reality of nature.
Einstein held the view that the world and, for that matter, the whole universe, is there independent of humanity. Tagore held the view that the world is a human world and hence without humanity, the world is irrelevant and non-existent. Einstein persisted and queried that aren’t beauty and truth absolute and independent of man? Tagore disagreed and said that truth is realised through man and without man it does not exist. The whole conversation between these two giants was absolutely fascinating – it brought out the mindset of a scientist seeking out nature as it exists and that of a poet observing nature through the eyes and minds of human beings.
Einstein’s commitment to the reality of nature was absolute, and that absolutism brought him into conflict with the quantum reality proposed by Niels Bohr, Werner Heisenberg and others. Einstein believed in the existence of causal, observer-independent reality; whereas quantum mechanics considers reality dependent on the act of observation. Bohr/Heisenberg proposed that an atomic particle like an electron is there only when it is observed. If it is not observed, it is not there; it could be anywhere only to be described by quantum functional description. But Einstein would not accept that. He retorted by saying that the moon is there in the sky whether you observe it or not. Quantum mechanics states that an entity having unobserved presence cannot be claimed to be present with absolute certainty (with the probability of 1). Quantum mechanics tell us that the observer and the observed are entwined. The reality is not pre-ordained; reality is what is observed.
In 1928, Tagore received Arnold Sommerfeld, professor of theoretical physics at the university of Munich and a pioneer of atomic spectra, at Shantiniketan, West Bengal. Sommerfeld stated, “Tagore is to India what Goethe (pronounced as Görta) is to Germany”. Sommerfeld’s student Werner Heisenberg visited India the following year.
Heisenberg was one of the principal architects of quantum mechanics and his ‘uncertainty principle’ is the cornerstone of quantum mechanics. During the 1920s, he, along with Niels Bohr and others, produced what is now known as the ‘Copenhagen Interpretation of quantum mechanics’, where multiple existence of an atomic particle at different locations with superposition of quantum states was considered to be the reality of nature.
Although quantum mechanics had enormous success and explained various physical phenomena, which classical physics was incapable of explaining, the conflict with Einstein on quantum mechanical fundamental assumptions of probabilistic description was deep rooted. Einstein considered quantum mechanics as an incomplete description of nature.
In 1929, when Heisenberg undertook a lecture tour around the world, he came to India. On 4 October 1929, he visited the University of Calcutta and in the afternoon, he visited Tagore. In fact, he was taken to Tagore’s house at Jorasanko by the scientist Debendra Mohan Bose, a nephew of Jagadish Chandra Bose, and they had a number of conversations over the next few days. Heisenberg was very much impressed by Tagore’s philosophical views. Fritjof Capra in his book Uncommon Wisdom wrote,:
“In 1929 Heisenberg spent some time in India as the guest of the celebrated Indian poet Rabindranath Tagore, with whom he had long conversations about science and Indian philosophy. The introduction to Indian thought brought Heisenberg great comfort. He began to see that the recognition of relativity, interconnectedness and impermanence as fundamental aspects of physical reality, which had been so difficult for himself and his fellow physicists, was the very basis of the Indian spiritual traditions.”
Heisenberg said, “After these conversations, some of the ideas that had seemed so crazy suddenly made much more sense. That was great help for me.”
Heisenberg’s comfort was to be seen in the context of a great intellectual battle that had been raging at that time between Einstein and Bohr/Heisenberg on the reality of nature. Indian mysticism or more accurately, Tagore’s interpretation of Oriental (Brahma) philosophy, giving a support to modern physics and quantum theory, was undoubtedly a great comfort to Heisenberg. No wonder, Heisenberg even said after their conversations that Tagore reminded him of a prophet of the old days!
Tagore’s philosophy of viewing the world with human eyes may seem to conflict with Einstein’s observer-independent reality, but these are two perspectives of the reality. Tagore’s view of reality resonates very well with the quantum philosophy of observer-dependent reality.
Dr A Rahman is an author and a columnist