Demystifying quantum mechanics I

Feynman’s statement

In one of his books, The Character of Physical Law (MIT Press: Cambridge, Massachusetts, 1995), Richard Feynman stated: “I think I can safely say that nobody understands quantum mechanics.”¬†Apparently, he also said “If you think you understand quantum mechanics, you don’t understand quantum mechanics”¬†in a talk with the same title as the book.

Richard Feynman

So it is quite clear that Feynman strongly believed that quantum mechanics is fundamentally incomprehensible. Who can argue with Feynman? He was a genius. If he said nobody can understand it, then nobody can understand it, right?

Genius or not, Feynman was just a human being. One should not elevate any person to such a level that their statements are considered to be cast in stone.

I don’t think that quantum mechanics is fundamentally incomprehensible. It is just that we don’t like what we learn. The way nature behaves at the fundamental level seems to contradict our intuition because it is so different from what we experience in our daily lives.

To be sure, there are things about the micro world that we simply cannot know. We know that atoms radiate photons, and that the atoms change their states when this happens. But we don’t know the exact mechanism by which such a photon is created.

The amazing thing about quantum mechanics is that it allows us to make reliable calculations without knowing these details. It is a way to encapsulate our ignorance and renders it innocuous, allowing us to use the little that we can know to make useful predictions.

Quantum mechanics is not the only scientific approach that allows one to make useful calculations amidst ignorance. Statistical analysis does the same. It also ignores the ignorance about the details and allows useful calculations exploiting the little that we do know.

What makes quantum mechanics more mysterious is that the part that we can know includes aspects that are strange to say the least. This strangeness has many manifestations, variously referred to as “the wave-particle duality,” “quantum uncertainty,” “quantum tunneling,” “quantum entanglement,” and many others.

A thorough understanding of these various aspects of quantum mechanics removes some of the strangeness. One can often identify the mechanisms with similar mechanisms in non-quantum scenarios without any strangeness.

However, within this understanding there usually remains an aspect that does not have any equivalent aspect in non-quantum scenarios. Distilling out this one aspect that makes things seem weird, one can refer to it as the notion of multiple realities.

People don’t like this idea of multiple realities. So they invented the idea of quantum collapse. However, there is no observable confirmation of quantum collapse. One can even argue that it is in principle impossible to observe quantum collapse, because it would have to be intrinsically involved in the process of observations. So this led to the so-called “measurement problem.”

The very fact the there are people that try to solve the measurement problem shows that they don’t buy into Feynman’s statement. They invest a significant amount of time and effort to understand something that Feynman believed could not be understood.

I don’t think the idea of multiple realities needs more understanding. It is the way it is, even if we don’t like it. I intend to say a bit more about it later.

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