Friday, November 25, 2011

Roads to Reality: The Clouds of Uncertainty

Physicists are an arrogant lot. And if Sheldon Cooper is any proof, they are usually quite happy being unapologetic about it. In an alternate universe, we probably pay our homage at the Cathedral of Science, with theoretical physicists presiding over as high priests. However, in our own version of the cosmos, I am willing to give them the benefit of a fertile imagination, given their knack of coming up with the weirdest explanations for everyday phenomenon. Therefore, it is a feast for the intellect when some of the brightest minds of a generation squabble over, quite literally, a dice.

Our classical sense of intuition tells us that in order to produce a change in a system (read ‘object’ if you are less scientifically minded) on the order side of a football field we will have to somehow negotiate the intervening space. That is what space does. We can shout, send a laser beam, or mail a postcard and wait for the cows to come home. Physicists and philosophers have a word for such a world view – local realism. Local realism posits that an objective reality exists even when it is not being observed and that an object can be influenced only by its immediate surroundings. It’s like what Winston Smith of 1984 would have us believe – “Sanity is not statistical”. Until the first two decades of the 20th century, no scientific development had challenged the locality of our universe. But all this was about to change.

The science of Quantum Mechanics (QM in all future references), developed primarily during the period between 1900 and 1930, breaks away completely with the tradition of a local, deterministic universe. It claims that one can not even know with certainty the position or velocity of a single particle, leave alone the evolution of the entire cosmos. Not only that, QM stipulates that prior to the act of measurement or observation, there is no point in even talking about such physical quantities. An electron could be here, in Andromeda Galaxy, or everywhere. Its behaviour can only be described by a fuzzy haze of probabilities, with no outcome being absolutely certain. Period. While relativity is counter-intuitive at best, QM is downright bizarre and malicious. It shatters our personal, individual conception of reality. God, it would seem, does like to play dice with the universe. And he rolls them blindfolded.

In order to interpret the physical properties of the micro-cosmos, QM uses a construct known as the ‘probability wave’. For example, if we are trying to study the position of an electron, the size of a wave at a given point in space is proportional to the probability that the electron is located at that point. But before the experiment is carried out and once its over, there is no way to determine for sure where it’ll be found. Identical experiments, performed under identical conditions, yield different results which agree with the probability profile of the electron’s probability wave. But is this wave thingamajig something real or just a convenient mathematical model that embodies all that we know and observe about the fundamental particles? Does quantum uncertainty tell us at that any moment particles simply do not possess a definite position?

This deconstruction of reality does not stop here. QM predicts the existence of ‘entangled’ particles that exist in a nebulous haze of uncertainty until one of them is forced to snap out of it when appropriately measured or interacted with. The outcome attained by any one of them is mirrored by each of the other entangled particles instantaneously, irrespective of the amount of space that separates them. If one decides to sport a pair of Ray Ban sunglasses, all the other entangled particles will choose to do so. They could be in two different corners of a room or at opposite ends of a galaxy – it doesn’t matter. This is dark magic or voodoo at its very best!
Naturally, this attack on the fundamental nature of reality did not sit well with Einstein. Over the course of many years, he mounted a series of ever more sophisticated challenges aimed at exposing the lacunae in quantum theory. He once reportedly said, “Do you really believe that the moon is not unless we are looking at it?” The stalwarts of QM were obviously not amused. So Einstein sought to provide a physical argument for this philosophical conundrum. In 1935, he published a paper with two of associates at Princeton – Podolsky and Rosen – which provided a theoretical basis for what has come to be known as the EPR Paradox. Using Heisenberg’s Uncertainty Principle, the authors argued that QM could not be a complete description of the physical reality and that a more fundamental theory is needed to understand it. For instance, it was argued ‘entangled’ particles displayed correlated properties simply because they had ‘hidden variables’ that programmed them to do so. Somewhat similar to two machines coming up with the same results even though they might be separated by a vast distance.

For several years the issue of who was right was left unresolved. Then in the 1960s, the Irish physicist John Bell showed that the debate could be settled experimentally. First in late 1980s and then later on through a series of progressively refined experiments, it has been proven conclusively that ‘spooky’ connections do exist between particles that defy our conventional notion of existence. What happens in Vegas doesn’t just stay there. Something like this should take your breath away! It affirms that a local universe may exist in our mind, but not in reality. What if our universe was nothing but a mirror image of an infinite number of entangled universes? As it is so poetically depicted in the movie Another Earth, is there the possibility that duplicate copies of our ‘selves’ exist? Would our choices mirror theirs?

The world according to the quantum is a strange place indeed. It forces us to abandon the idea of a local universe. It also throws out the window the notion of an objective reality – one that has always existed. The act of observation, hence, becomes closely intertwined with the process of creating the very reality that is being observed. In effect, this theory is incredibly efficient: it explains what you observe with mind boggling accuracy but prevents you from seeing the explanation. And therein lays the problem of reconciling our day to day experience of life with the weird microscopic reality revealed to us by quantum mechanics. Wasn’t life complicated enough to begin with?

Our society is structured according to the way we understand reality. Our definitions of truth, free will, justice are intricately tied to this understanding. To undermine its importance in the context of our own lives is to be deliberately short-sighted. And to ignore its implication, a fool’s paradise. So is that it? Is our reality merely a game of chance? Is Schrödinger’s cat really alive and dead at the same time? In my next article, I will try to dwell upon the different interpretations of quantum mechanics and what promises they hold for our understanding of that most elusive of phantoms – reality.

The first article in this series is available here:

PS: If you are interested in the details of the arguments presented in the EPR Paradox, I suggest you read the original paper. It is not very long and Einstein's grouse with quantum theory has been expressed very succinctly. Here is the link to it - Just ignore all the mathematics and concentrate on the parts mentioned on Page 1 and Page 4.

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Monday, November 21, 2011

Roads to Reality: Einstein and Faith

PS — Somebody read this post and emailed me saying that this - - might be a fun addition to all the serious stuff here! I am inclined to agree : )

“There is but one truly philosophical problem, and that is suicide.” Thus begins Albert Camus’s seminal work in existential philosophy – The Myth of Sisyphus. The premise of the book is an ancient legend in which the Greek hero, Sisyphus, is eternally condemned to the task of pushing a rock up a mountain, knowing very well that it will roll back down. The million dollar question here – How does Sisyphus commit himself to a life without purpose, even bordering on the absurd? If his perception of reality were to change, would he see a silver lining? Camus acknowledges the significance of understanding the nature of the universe, but rejects the likelihood that such an understanding would effect our assessment of life’s worth. I beg to disagree.

It is true that reality is revealed to us through our experiences. But its arena is not just the world we inhabit. The overarching lesson from the past two centuries of scientific discovery is that our senses are often a misleading guide to the true nature of reality. In his book, The Fabric of the Cosmos, physicist Brian Greene aptly surmises this experience as – “gazing at a van Gogh through an empty Coke bottle”. Lying just beneath the surface of our perception is a world that will take our breath away. Through the tireless efforts of eccentric geniuses, mad scientists, and indefatigable innovators, we have been able to peel away layer after layer of this beautiful reality and come one step closer to understanding it. I feel that any assessment of existence that fails to incorporate the insights provided by modern science is not only incomplete but also juvenile.

Few scientists or their discoveries have achieved such ubiquity as Albert Einstein and his Theory of Relativity – with perhaps the notable exception of Sir Isaac Newton. A downside of such fame was that his statements and remarks were often blown out of proportion. So when Einstein claimed that he was religious, religious leaders latched onto his words and sought to use them in order to sanction their brand of God Almighty. But there is a quote that is frequently attributed to the great physicist – “Make everything as simple as possible, but not simpler”. Wary of being quoted out of context, he sought to express himself clearly on the subject, both for himself and for the sake of those who wanted a simple answer from him. So in the summer of 1930 he composed a credo – ‘What I Believe’ – that he released to a human rights group and later on published.

Throughout his life, Einstein maintained that underneath all the discernible laws of physics, there is a mysterious force, subtle and intangible, that is responsible for the harmony that we see around us. Veneration for this enigmatic power constituted his religion. He wrote, “To sense that behind anything that can be experienced there is something that our minds cannot grasp, whose beauty and sublimity reaches us only indirectly: this is religiousness. In this sense, and in this sense only, I am a devoutly religious man.” The mandate of science, according to him, was to hack away at this mystery and reveal to us those fundamental laws of nature that governed the ‘music of the spheres’. He gave no weight to the idea of a personal God who could meddle at whim in the affairs or mortal men.

A natural conclusion from this world view was Einstein’s belief in causal determinism. The world obeyed laws and we are just as bound to them as the planets that revolve around the stars. Were the immutable rules of nature revealed to us, it would be possible to predict with certainty if it will rain tomorrow at 4.15 in the afternoon and whether Mr. Sharma, a government clerk working in Jhumri Tilaiya, will choose to vaccinate his third child. Obviously, this was incompatible with the notion of free will, the very basis of moral behaviour and ethical freedom, and outraged several of his fellow physicists, including Max Born, who looked upon a deterministic world as downright ‘abhorrent’.

But that did little to dissuade Einstein. He famously quoted Schopenhauer in his credo – “A man can do as he wills, but not will as he wills”. Free will, in his view, was nothing more than a convenient construct that allowed civilised society to exist. Something that allowed people to rise above the ‘merely personal’ and live in a way that benefited humanity. “I know that philosophically a murderer is not responsible for his crime,” he said, “but I prefer not to take tea with him.”

In light of the groundbreaking success that his theories have had over the last 100 years, I found it a bit difficult to digest the notion that someone like Einstein could be religious. In fact, he was more critical of the fanatical atheists who “lacked utter humility toward the unattainable secrets of the harmony of the cosmos”. But that is when his words came to the rescue. Einstein believed that only a person thoroughly imbued with an aspiration for truth and understanding can do science. The source for that inspiration, however, lies in the sphere of religion. In other words (or more precisely, in his words), “science without religion is lame, religion without science is blind”.

But there was one religious concept that he could not accept. The bone of contention between religion and science, Einstein argued, lay in the concept of a personal God – someone who could randomly alter the course of events once they have been set into motion. A scientist on the quest for discovering the laws of reality must reject the notion that divine will, or for that matter human will, can influence this cosmic causality.

But even during the course of his life, a new sun was looming on the horizon of modern science. Few discoveries have so drastically affected our understanding of the machinations of the universe in recent times. Quantum Mechanics and the uncertainty woven into its fabric was about to deliver a knockout punch to the idea of a deterministic world. Deeply troubled by this assault on the very nature of reality, Einstein mounted a series of attacks against this emerging field in his later years. Physicists, he would emphasise, are not bookies and physics is not in the business of determining odds. Did he succeed in his mission or has our understanding been subjected to yet another upheaval? What implications does Quantum Mechanics have for our grasp over reality? More importantly, is this the only reality that exists? I will try to elaborate on some of these questions in the next article in this series.