Quantum Mechanics And Many Worlds: A Glimpse Of ‘Something Deeply Hidden’ That Humbles Us

Something Deeply Hidden. Sean Caroll. Dutton. 368 Pages. $20.00 (Hardcover).

The advertisement for a motorbike highlights the ‘quantum technology’ used in the bike. The friendly neighborhood spiritual conman appearing on television speaks about ‘quantum entanglement’ of the Guru.

It seems these days everyone has gone ‘quantum’. But do we understand what it is?

Sean Carroll --- a fine theoretical physicist and a very good science writer --- has taken it upon himself to introduce us ordinary people to the challenges physicists face in tackling the weird world of quantum mechanics and the exciting world views that emerge from their attempts.

This, almost Bhagirath-ic task, he takes up in his latest book, Something Deeply Hidden.

Carroll points out at the outset:

The paradoxes that arise out of marrying quantum mechanics to Einstein’s General Theory of Relativity forms the springboard from which we take the plunge into this weird world of spooky actions and entanglements.

Carroll is the great messenger who is bringing three clear-cut messages to his readers.

The first is that quantum mechanics is understandable --- “even if we are not yet there”. The second message he wants to convey is that “we are getting there”.

And the third message is that it is lovely and that it all matters --- not just for science but for our own understanding of “the nature of spacetime itself, and the origin and ultimate fate of the entire universe”.

The book is a lucid journey into the heart of matter in more than one sense.

Carroll favours the ‘Many-Worlds’ formulation. This was first proposed in 1957 by American physicist Hugh Everett.

Bruce DeWitt, a fellow physicist and editor of the journal where Everett first published his formulation, criticised the Many-Worlds theory, complaining that he could not feel such a splitting himself.

Everett countered that with another famous reply that came from another revolution in the annals of history --- the Copernican:

DeWitt was finally won over by the ‘Many-Worlds’ formulation.

The book is lucid for a non-physicist reader and yet there is no compromise on rigour in bringing the concepts to the reader either.

An almost Upanishadic father-daughter dialogue, 'Does This Ontological Commitment Make Me Look Fat?' that forms the eighth chapter is a delight to read.

The daughter is Alice, a PhD in physics who teaches philosophy at a University and is considered quite an expert in the Many-Worlds interpretation. Her father has a passion for experimental physics.

The conversation starts nicely with Occam’s razor --- the idea that the explanation that requires the least amount of assumptions is usually correct.

So, there is the father firing the first salvo: is not 'postulating an infinite number of unseen worlds' directly 'the opposite of the simplest possible explanation?'

Alice counters the opposition by pointing out that it is not an assumption of a large number of worlds but an assumption that is only a wave function, which, in turn, evolves automatically into many worlds.

The assumption for Many-Worlds consists of the basic minimum components of any quantum mechanics version. It is to get rid of these many worlds that one has to make multiple assumptions. So actually, the Many-Worlds theory fits the celebrated Occam's razor better than other alternatives.

Then, the father brings in Karl Popper’s falsifiability criterion:‘”If you can’t even imagine an experiment that might prove your theory wrong, it’s not really science. That’s exactly the situation with all these other worlds, isn’t it?”

Here, through the daughter’s character, Sean Carroll marks an important aspect of the philosophy of science. When Popper made falsifiability the criterion he had in mind dialectical materialism, Freudian psychoanalysis, not to mention astrology.

So the essence of his falsifiability criterion is that to be a good scientific theory it should be definite and empirical. "And Many-Worlds embodies both,” Alice informs her father.

One important aspect of quantum mechanics in the context of Western philosophy is that it stopped the onward march of materialism in the context of the Cartesian divide.

Moving from Cartesian dualism to non-dualism, a materialist monism is favoured in all science domains except in quantum mechanics because of the observer’s role, points out Carroll.

But not anymore if ‘Many-Worlds’ is the solution. He says:

Validating either idealism or materialism through quantum mechanics is, in a way, the ghost of Descartes.

In Indian Darshana traditions such a distinction does not exist. Consciousness and Matter, if at all they should be considered two separate entities, are still so organically intertwined that it is hard to say where one starts and where one ends.

Even as that is as it is, the supposed exorcism of consciousness through ‘Many-Worlds interpretation’ still does not take away the deep mystery that abides in all existence.

Drawing a parallel between increasing entropy and an increasing number of worlds that get formed every moment, Carroll tells the readers, “In both cases (entropy and Many-Worlds) we are poor finite creatures with dramatically incomplete information, and invoking these higher-level concepts is extremely useful.”

This humbling feeling is integral to the spirit of science. And when we think of the infinite number of worlds branching out at every moment, we cannot but say with a sense of surrender before the mystery of existence: Unmesha Nimsihotpanna Vipanna Bhuvanavali.