October 23, 2011

On the Nature of Light

Light is at the core of physics. Light, its attributes and energy, define the very parameters of this amazing universe that we find ourselves in. The nature of light, also (less commonly) known by its scientific name – electromagnetic radiation (EMR) – is the most fascinating conundrum we have encountered in nature. Light is the two-faced Janus, connecting our past, present and future, and, for mysterious reasons, can behave as either a ‘wave’ or a ‘particle’. This is no ordinary matter. How light can behave at times like a “particle” – something that has “mass” and confined to “finite amount of space”, and on other occasions, as a “wave” – something that is formless and existing everywhere simultaneously – is one of the most captivating mysteries that science is yet to solve.

On the Nature of Light

Long before before great scientists like Aristotle, Galileo and Newton came along, humans had grasped the mystical importance of light, in a philosophical and religious sense.

Psalms 119:105  (Holy Bible, King James Version):  “Thy word is a lamp unto my feet, and a light unto my path”

“Seeing the light” came to be equated with wisdom and enlightenment, and with receiving the ultimate expression of God’s benevolence. A dark universe, devoid of light, was considered a universe devoid of itself – a universe that existed without form or purpose until – as the Holy Bible tells us – “God said, Let there be light”. The Holy Koran says, “Allah, (Praise be to his name) is the light of the heavens and the earth”. The Rig Vedantin prayed “Lead me from darkness to light, from the unreal to the real”. The ancient savants intuitively grasped the quixotic nature of light, a baton which science has only recently taken but carried resolutely over the last hundred years.The Eye Sees Only What the Mind is Prepared to Comprehend

The visual system in humans allows us to assimilate information from the environment. The act of seeing begins when the lens of the eye focuses an image onto a light-sensitive membrane in the back of the eye called the retina. The interesting thing about visual perception is that what we see is not simply a translation of retinal images.  A scientist by the name of Hermann von Helmholtz, credited with the study of visual perception, examined the human eye and concluded that it was, “optically rather poor”. The poor quality of information gathered by the eye seemed to make vision – as we experience it – impossible. He logically concluded that vision could only be the result of unconscious inferences – of making assumptions and conclusions from incomplete data, based on previous experiences – by the brain. This, in industry parlance, is called “top-down processing”. In other words, the eye sees only what the mind is prepared to comprehend. This insight forms the basis of cognitive neuroscience and techniques such as hypnotherapy – where the “top” (mind) is manipulated to make the “bottom” (subject) perceive an altered reality.

Goldfishes in a Bowl

Reality that we perceive, so it seems, is not quite real. For example, some of the stars which we so plainly see in the night sky with our own eyes are not really there. They may have moved or even died by the time we see them. This “unreality” is because it takes a long while for the light from the stars to reach us. Thanks to science, we know of this time lag. Even our own beloved sun is eight minutes older by the time we see it. This is not a problem in practicality, as we don’t really need to know what exactly is going on in the sun or anywhere else in the universe “right now”. But, those who seeking to find the nature of “reality” will have to adjust for distortions in the way it is perceived.

Our view of the world is constantly distorted by something or the other, starting with the genetic and cultural dispositions that we inherit. Take the example of a goldfish in a bowl (a lovely example illustrated in Stephen Hawking’s latest book “The Grand Design”).

Read A Divine Review – Laughing Gas take on “Grand Design” by Stephen Hawking

The goldfish views the world through the curved glass walls of the bowl. Although an object outside the bowl may be moving along a straight line, the goldfish will view it as moving along a curved line. Certainly, we cannot fault the goldfish for believing itself to be right or for its perception of reality.

 

If this were not perplexing enough, we have situations where we do not have the luxury of observing things directly “for ourselves’. Instead, we can only get to know of them by observing the effects they cause. Be it the air we breathe or a black hole in the universe or the “dark matter” that fills two thirds of the universe – we have not or cannot see any of these directly. We sense their presence subtly through experiment, inference and insight. It is a matter of fact that much of scientific discovery in the last hundred years has been in the realms of the intangible and the invisible. Science, while it has extricated itself from a dependency on visualization and the tangible, has begun to resemble philosophy and metaphysics. Today’s physics has morphed into essentially mathematics and complex modelling, and is filled with ideas like the “m-theory” which postulates that our universe is one of many universes that co-exist and  uses a eleven dimensional model to describe it. Yes, that’s right, eleven dimensions.

math is a religion

Is there a dividing line between optical illusion and truth? This is one of the oldest questions in philosophy – that age old debate between the nous (mind) or the ‘purusha’ and the phenomenon (sensory) or the ‘prakriti’ – which debates the distinction between knowledge and reality. Knowledge is our view of something. Reality is that which is “actually the case”. In other words, knowledge is an abstract internalization of an ‘ultimate reality’.

The point is that we are all goldfishes in our respective bowls watching the world through our individual lenses – and each of us has a perception of reality, which might hold in our reference frame. The nature of reality is relative, as famously explained by Einstein through his theory of relativity. We have two choices in dealing with this rather distressing state of affairs. We can accept the distortions as “yet another reality” and move on – which is what science does. We also have the option of assuming a “higher reality” – one whose nature we cannot fathom and can only conjecture in “blind faith”. Neither is particularly more right than the other.  It wouldn’t make sense to even begin to draw such comparisons. Importantly, they are not mutually exclusive, which is to say that these two assumptions or approaches can co-exist, and the presence of one does not predicate the other’s absence. Scientific and spiritual wonderment are not natural enemies – as they are sometimes made out to be. In fact, they might be closer than we think.

Traveling Light

The best we can do, under the circs, is to seek to reduce the distortions – by eliminating biases and preconceived notions of the world. That just may lead to an incredible lightness of the being – a state described by mystics as “sat-chit-ananda”.

Light, with its paradoxical nature, is possibly our best metaphor for understanding the spirit of the universe. It straddles that delicate line between being (matter) and non-being (subtle). Perceptibly real, and yet devoid of the qualities we attribute to the objects of our perceptible universe, light is the bridge that connects the mind grounded in a material world and the metaphysical abstractions it contemplates.

By contemplating the nature of light – perhaps the most ethereal and spiritual of all “things” — we can begin to understand that existence must not be defined only in terms of its own being, but as a means to illuminate a higher truth. Our grand universe, which simply exists and conducts its business without prejudice or judgement – teaches us this truth through its pure expression of light, which illumines without its own personality getting in the way. Indeed, light may be the closest we have come to seeing the One that some like to call God.

This Deepavali, as we light our lovely little lamps, perhaps we might want to think of that.

There is not enough darkness in this world to put out even the smallest of lamps.

Happy Deepavali!

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