The central problem of quantum physics is not wave-particle duality but the nature of reality.

N.S. Rajaram


The central problem of quantum physics is not wave-particle duality but the nature of reality.

N.S. Rajaram

Veda and Vedanta: primary and derived knowledge

            The Indic (Hindu) knowledge system does not draw a clear line separating the natural sciences and the humanities. It does, however, make a clear distinction between knowledge that is paurusheya (human created) and apaurusheya (of primary, non-human source). Apaurusheya knowledge is called shruti or sensed while the paurusheya knowledge is often referred to as smriti or recalled. Smriti is derivative while shruti is primary.

            Veda is apaurusheya, which means that only primary knowledge (or shruti) has the right to be called Veda. Vedanta refers to the body of knowledge derived by human thinkers and other workers based on the Veda. In the present article and in much of my work relating to science and Vedanta I find it convenient to use this as the working definition. I feel there are advantages to taking such a clear cut position in today’s world. (It is best not to engage in endless hairsplitting over the etymology of Veda and Vedanta both of which can be derived from the root vid.)

Patanjali in his Yogasutra observes: pratyaksha (direct), anumana (inferred or derived), agama (compiled) and others not germane here. His commentator Badarayana Vyasa makes the pregnant observation that anyone accepting derived knowledge implicitly assumes that someone has direct knowledge (pratyaksha) from which it has been derived.

It is important to note here that Vedanta, which is what our work involves, makes no demand on our religious belief or even belief in any god; this is not to say you have to be an atheist, only that much of Vedanta and Vedanga are non-theistic— they don’t make any religious demands. Like science and mathematics Vedanta is a philosophical cum metaphysical system (or systems) that address the great questions of the world. It leaves religious belief to the individual. This is one of the main reasons why Hinduism has never clashed with science.

Metaphysics, not theology

It is important to emphasize this point: Vedanta is a philosophic system and not a collection of religious texts. Confounding Vedanta and ‘religious’ Hinduism has done disservice to both. Indian philosophy is metaphysical and not theological. It is concerned with issues of existence (ontology), perception and reality (epistemology) more than justifying the existence of God and devotion to him (or her). In particular, the question of reality occupies a central place in Vedanta as it does in quantum physics.

As I hope will become clear from the rest of the article, Vedanta is a powerful metaphysical system that can and has shed light on some of the fundamental problems of modern science. (Erwin Schrödinger claimed he derived his fundamental idea of the ‘wave function’ in quantum physics from Vedanta.)  No problem in physics today is more important than the problem of reality. The rest of the article is devoted to the problem of reality and what physics and Vedanta have to say about it. What follows is a summary.

Reality in modern physics

            Until about a century ago scientists didn’t worry much about the reality of the physical world they were trying to understand. They implicitly assumed that things they were observing and measuring were real. When doubts arose about the reality of some ideas used in their theories, like light waves in the eighteenth century, they assumed that the question would be resolved by some clever experiment. This did happen in 1801 when Thomas Young in a famous experiment demonstrated the wave nature of light.

But the situation began to change when scientists started introducing into their theories things like atoms that could not directly be observed. Even in the twentieth century there were scientists who refused to believe that atoms were real. What convinced scientists was not any experiment but Einstein’s explanation of the irregular movement of particles suspended in a liquid, a phenomenon known as Brownian motion. Jean Perrin’s 1909 experiment verified one of Einstein’s predictions based on the atomic theory of Brownian motion without actually observing atoms. This was the beginning of atomic physics that soon became entangled with quantum theory and all that came with it. (This is an oversimplification, but will do here.)

No one today doubts the reality of the quantum any more than the reality of the atom, but Max Planck in 1900 had introduced it as a purely mathematical device in a desperate attempt to resolve some anomalies observed in heat radiation; he never believed that the quantum had a physical existence. Five years later, Einstein extended the quantum idea to light to explain the photoelectric effect which the wave theory could not. As he saw it, light flowed not in a continuous stream like water but in discrete lumps like ice cubes out of a vending machine.

Unlike Planck, Einstein had no doubt that his light quanta, now called photons were real. He also realized that he had brought about a fundamental change in physics. Writing to a friend in 1905, the ‘miracle year’ in which he created the special theory of relativity, explained Brownian motion and introduced the light quantum, he described only the last as being ‘truly revolutionary’. At a conference in Salzburg in 1909 Einstein proclaimed: “The next phase of the development of theoretical physics will bring us a theory of light that can be interpreted as a kind of fusion of the wave and particle theories.”

Neither Einstein nor anyone else in 1909 could know where this wave-particle duality of light would take physics. At first, things seemed natural enough with the Bohr-Sommerfeld model of the atom explaining light emission and spectral lines, though Niels Bohr, soon to be recognized as the second seminal figure of twentieth century physics (after Einstein) professed that he didn’t care for Einstein’s light quantum idea.

In his relativity theory Einstein had already shown that matter and energy are one and the same; now he was saying that light, which is a form of energy, is both waves and particles. Louis de Broglie connected the two and proposed that matter also had waves. This too received experimental support. Next, if matter can be a wave, there must be a wave equation describing it. This was supplied by Erwin Schrödinger (a self-confessed student of Vedanta) top, though no one at first seemed to understand what it was wave of.

Then Max Born offered the explanation that it was not really a wave like a water wave or a sound wave, but an abstract mathematical function that allowed one to calculate the probability of where a particle like electron would be found. This is coming a full circle since Plank had introduced the quantum as a mathematical entity in the first place.

Limit on knowledge

            The reality question arises because in the quantum world, the observer cannot be removed from the phenomenon. Whether light is a wave or a particle depends on the experiment being performed. Unlike Newton’s Laws of Motion which are independent of the observer, as is the velocity of light, quantum phenomena depend on the observer. They have no independent existence. Even this is limited in the following way.

Bohr, Heisenberg and Pauli

Werner Heisenberg threw a bombshell into this conundrum with what is now called the uncertainty principle. He claimed that it is impossible to know both the position and the momentum (or velocity) of a particle exactly. Just as Einstein’s relativity theory placed a limit on velocity, Heisenberg’s uncertainty principle placed a limit on knowledge. All one can calculate is the probability of a particle like the electron going from one place to another, say from the earth to the moon, and not the path by which it gets there. Worse, the electron doesn’t even exist until we observe it on the moon. So it is the observer that defines its existence.

So here was the new reality: a wave equation without a wave that is needed to find a particle that becomes real only when we observe it. As Heisenberg saw it, “Reality has evaporated into mathematics.” His colleague Pascual Jordan, who might have won a Nobel Prize but for his unsavory politics (he became a Nazi storm trooper) said, “There is no reality; we ourselves create things with our experiments.” Bohr, the high priest of this new physics proclaimed: “Physics is not about reality but about our knowledge of reality.”

This gives new meanings to the concept of reality: reality of the physical world and reality of the world described by our physical theories. Acharya Madhva had anticipated it over five centuries ago, as we shall see in due course. This gives an altogether different meaning to the term duality, not only physical but also of existence (or ontological).

Einstein was unhappy with the turn of events in the revolution that he had done so much to launch. To him the physical world was reality, not something that evaporated into its mathematical dual created by physicists. “Do you really believe that the moon exists only when I am looking at it?” He once asked.

The curious thing is that this metaphysical muddle grew out of experiments, not just philosophical speculation. Theologians like Saint Augustine and Saint Bonaventure were always interested in reality, even if only as a preliminary to their theology. But they took its existence for granted, as the work of God. Even Newton believed God’s intervention might be necessary to maintain the stability of the solar system. His successor Pierre Simon de Laplace, the founder of both celestial mechanics and probability theory saw no such need. When Napoleon berated him for not mentioning the Creator in his masterwork on celestial mechanics, Laplace retorted: “Sire, I have no need of that hypothesis.”

Vedanta sheds light on the reality question

To make sense of this mass of contradictions, some of the pioneers like Schrödinger, Heisenberg, Robert Oppenheimer and David Bohm turned to eastern philosophy. There they found that problems lying at the center of new physics like reality, and existence had received the attention of Hindu philosophers of the school known as Vedanta (of which Yoga is probably the best known).

Madhva’s orders of reality

The medieval philosopher Madhva (1238 – 1317, left) had explicitly observed: “There are two orders of Reality─ independent and the dependent.” And in what may be seen as an anticipation of physicist Hugh Everett’s many worlds interpretation of quantum physics, Madhva asserted: “The knowledge of the many through knowledge of the One, is to be understood in terms of the preeminence of the One.”

His predecessor Shankara (788 – 821) saw the world as conceived in latent form in pure consciousness like the tree in a seed. “The relation between the world of multiplicity and the Absolute is an inconceivable one,” he wrote. Shankara, some of whose ideas are close to those of Immanuel Kant. Shankara, unlike Laplace didn’t have to contend with Napoleon, but he did have to deal with Hindu and Buddhist critics who held up scripture as authority. Anticipating Laplace by a thousand years Shankara retorted:

“Scripture is not any word of God, but consists entirely of perceived truths. This perception can be from karma (actions or empirical observations) and jnana (gnosis or thought) through reflection or deduction.” And most significantly for our purposes, he claimed: “Any attempt to connect the Absolute with its manifestations in the shape of the world must end in failure, for no relation can be imagined beyond the sphere of duality.”

How did they see the problem of reality, centuries before it arose in physics? Where does all this leave us? Reality and our conception of it, can the twain never meet?

Vedanta and Reality

I see the question of Reality as the meeting ground between Vedanata and modern physics, especially quantum mechanics. Reality is the Holy Grail of quantum physics; it is an area in which Vedanta can make a contribution and thereby come to occupy the center stage in modern metaphysics.

At the same time, we should refrain from making excessive claims. Vedanta is not a mathematical or quantitative system. Any comparison can only be at the metaphysical level, without mathematics. Quantum physics is mathematics, too much so according to some critics like Lee Smolin (Trouble with physics), with the tail of mathematical physics often wagging the dog. Some mathematical models like String Theory have no physical counterpart.

As just noted, the same question was asked, and partly answered by Vedantic thinkers like Shankara and Madhva centuries ago, and is being asked again beginning with Albert Einstein nearly a hundred years ago and now by many others, notably John Stuart Bell of Bell’s theorem fame. A point I would like to emphasize is: raising questions about Reality in the Vedantic context should not be seen as advocating other-worldliness. (In any event otherworldliness is less a Hindu idea than Buddhist and Jain notion.)

As I observed earlier, the Reality question lies at the heart of quantum physics and we should welcome any efforts to bring Vedanta into the picture.  It is a tribute to our ancestors that they had addressed the same question centuries ago. The real question is the relationship between their thought and that of modern physics. Here are a few examples from some of the greatest scientific thinkers of the 20th century.

No objective reality?

The concept of objective Reality… evaporated into mathematics that no longer represents the behavior of elementary particles but rather our knowledge of it.

Werner Heisenberg

Through the creation of quantum mechanics, the concept of consciousness came to the fore again; it was not possible to formulate the laws of quantum mechanics in a fully consistent way without reference to the consciousness.

…it is this entering of an impression into our consciousness which alters the wave function.

Eugene Wigner

… there is no [reality]. We ourselves produce the results of the measurement.

Pascual Jordan

Quantum mechanics says that nature is unintelligible except as a calculus, that all you can do is to compute with the equations and operate your apparatus and compare the result.[with the predicted values].

David Bohm

Do you really believe that the moon only exists when I am looking at it?

Albert Einstein

This means that the notion of reality is an illusion (or maya). It is interesting to compare these with what Indian Vedantic thinkers had to say. Madhva, an early Indian philosopher schooled in Vedantic metaphysics wrote: “There are two orders of Reality─ independent and the dependent.” (I would rephrase the original Sanskrit svatantra and paratantra as ‘coherent’ and ‘incoherent’— with the coherent referring to the observable world and the incoherent to the unobservable quantum world.

In this the goal of Madhva’s metaphysics was “not merely to realize the distinction between appearance and Reality, but to understand and appreciate the still more fundamental difference between Independent Reality and dependent realities.” This according to Einstein should be the goal of quantum physics also.

This sense of duality lies at the heart of Madhva’s philosophy as it does in quantum mechanics also for which reason it is known as the dvaita (dual) school. Madhva then goes deeper into the subject; invoking ancient Vedantic texts known as the Upanishads he goes on to observe: “The knowledge of the many through knowledge of the One, taught so prominently in the Upanishads, is to be understood in terms of the preeminence of the One; or by virtue of some similarity (of natures) between them; or on account of the One being the cause of the many…”

Nor is this an isolated case, but the culmination of a centuries-long quest for the nature of Reality. Madhva’s predecessor Shankara took the radical view that scripture is not any word of God, but consists entirely of perceived truths. This perception can be from karma (actions or empirical) and jnana (gnosis or thought) i.e., through reflection or deduction. Shankara’s eminent modern commentator S. Radhakrishnan explains the situation as follows:

“The relation between the world of multiplicity and the Absolute is an inconceivable one and this inconceivability is denoted by the word Maya.” Thus Maya is not illusion as often mistranslated, but inconceivable. He further comments: “Any attempt to connect the Absolute with its manifestations in the shape of the world must end in failure, for no relation can be imagined beyond the sphere of duality.”

From this we may see that some of the central problems of modern physics like Duality, Reality, Consciousness and observables had engaged the great philosophical minds of Classical India. I feel that this metaphysical convergence of science and Vedanta is of fundamental importance to both. This does not rule out other approaches, but has the potential to attract talented youngsters as I found during my lectures in the U.S., U.K. as well as in India. It is important for aspiring young minds to see Vedanta as a powerful metaphysical tool that can shed light on fundamental problems. It is no more a mere antiquarian tool than the zero and the place value system, thousands of years old.

Based in part on lectures given at the University of Manchester, U.K and MIT, Cambridge, MA. I am grateful to the late Professor K.T. Pandurangi for enlightening me on certain aspects of Vedanta, especially relating to the much neglected Dvaita (dual) school of Madhvacharya.



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