Monday, August 27, 2012

Quantum mechanics and a revision of epistemological belief

I have signed up for a course on Quantum mechanics and quantum computation at – a very interesting site for a wealth of short courses from 18 of the world’s best universities. As I went through the course, I came across a very intriguing characteristic of quantum mechanics namely the nearly untrue mathematical abstractness of it all.

To be fair, the greatest minds in quantum mechanics had always maintained that there is nothing intuitive about quantum mechanics. Consider this quote of Niels Bohr for example,

“If anybody says he can think about quantum physics without getting giddy, that only shows he has not understood the first thing about them.”

As I went through some of the basic principles, I realized how true this was. Coming to the more direct impact on my thinking though, I have been forced to revise my near-religious faith in the “trueness” of the theories of physics. From a rational point of view I have always believed (after the first year at IITB, post the course in introduction to philosophy) that no knowledge is certain, no theory is “right” (but many are wrong!) and there is no finality to any of our understanding of the world. Everything is tentative and subject to refinement – not only in calculation and observation but also in the very model of reality we have constructed on the basis of it.

However, emotionally I was always a believer in our current model of the universe – however incomplete it might be. The belief was that it was in the generally correct line – and needed refinement. As I think more objectively, it is qualitatively no better than the worldview few centuries ago (and I might even go a step further and say many thousands of years ago as well).

Why is that? Well, for one, quantum mechanics is a reaction to the various paradoxes observed at the atomic level (e.g. the wave-particle duality of photons). It does not seem to answer why nature is organized a certain way, it only aspires to describe its working in a manner consistent with observation. That in itself is an ambitious goal no doubt. The abstractions required to achieve “explanability” in quantum mechanics sometimes robs one of any intuitive feel for it.

That is an absurd criterion for something being right, I understand. Intuition is a faculty evolved in human beings for purposes entirely different from understanding the nature of reality. Hence intuition does fail very often while considering phenomenon far removed from day to day life in terms of size, complexity and duration. That does not make these phenomena non-existent or inexplicable. The description of such phenomena will hence remain a story legible to our rational minds but not to our intuition.

So far so good! But that also means I have no way of knowing if the theory is any closer to truth than the earlier one. It fits experimental observations better – but that is a very indirect and circumstantial evidence. One may point out that that is pretty much all on offer in the current organization of our present universe. However, that is tantamount to saying – this is life, live with it. It does not make the theories more accurate. Hence the abovementioned revision in my faith in physics.

What is the revised thought then? It goes as follows. Physics and allied sciences are human endeavours to understand the way nature works. They are supported by human faculties of analysis and imagination as also apparatus for making measurements to an appropriately desired level of accuracy. The models of reality produced by these endeavours are working prototypes of the way we see the world. Like any other models the following basic truth applies to them – “all models are wrong; some are useful!”