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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Transcending the impasse, part VI

A little bit of meta-physics

Anyone that has read some of my previous posts may know that I’m not a big fan of philosophy. However, I admit that philosophy can sometimes have some benefits. It occurs to me that, if we want to transcend the impasse in fundamental physics, we may need to take one step back; stand outside the realm of science and view our activities a bit more critically.

Yeah well flippiefanus, what do you think all the philosophers of science are doing? OK, maybe I’m not going to be jumping so deeply into the fray. Only a tiny little step, just enough to say something about the meta-physics of those aspects most pertinent to the problem.

So what is most pertinent to the problem? Someone said that we need to go back and make sure that we sort out the mistakes and misconceptions. That idea resonates with me. However, it is inevitable in the diverse nature of humans to do that anyway. The problem is that if somebody finds something that seems incorrect in our current understanding, then it is generally very difficult to convince people that it is something that needs to be corrected.

What I want to propose here is a slightly different approach. We need to get rid of the clutter.

Clutter in our theory space

There is such a large amount of clutter in our way of looking at the physical world. Much of this clutter is a kind of curtain that we use to hide our ignorance behind. I guess it is human to try hiding one’s ignorance and what better way to do that by dumping a lot of befuddling nonsense over it.

Take for instance quantum mechanics. One often hears about quantum weirdness or the statement that nobody can really understand quantum physics. This mystery that anything quantum represents is one such curtain that people draw over their ignorance. I don’t think that it is impossible to understand quantum mechanics. It is just that we don’t like what we learn.

So what I propose is a minimalist approach. The idea is to identify the core of our understand about a phenomenon and put everything else in the proper perspective without cluttering it with nonsense. The idea of minimalism resonates with the idea of Occam’s razor. It states that the simplest explanation is probably the correct one.

To support the idea of minimalism in physics, we can remind ourselves that scientific theories are constructs that we compile in our minds to help us make sense of the physical world. One should be wary of confusing the two. That opens up the possibility that there may always be multiple theoretical constructs that successfully describe the same physical phenomena. Minimalism tells us to look for the simplest one among them. Those that are more complicated may contain unnecessary clutter that will inevitably just confuse us later.

To give a concrete example of this situation, we can think of the current so-called measurement problem. Previous, I explained that one can avoid any issues related to the measurement problem and the enigma of quantum collapse by resorting to the many-worlds interpretation. This choice enforces the principle of minimalism by selecting the simplest interpretation. Thereby, we are getting rid of the unnecessary clutter of quantum collapse.

This example is somewhat beyond science, because the interpretations of quantum mechanics is not (currently?) a scientific topic. However, there are other examples where we can also apply the minimalist principle. Perhaps I’ll write about that some other day.

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Transcending the impasse, part I

The current impasse in fundamental physics stifles progress. The rate of advances in our understand has slowed down. Although several exotic predictions have been made in recent years, none of these seem to be correct. Have we reached the end of our ability to learn more about the universe we live in?

It has been suggested that the way forward is to go back and fix what is wrong. Is there then something wrong with what we’ve learned before? Apparently yes. We are biased by what we think we know. It misleads us to conjure up theories that cannot work.

How is this possible? Would such misconceptions not have been ruled out by experimental observation? That’s the problem. Much of what we think we know never got tested by experimental observations.

As an example, one is reminded of all the aspects of quantum physics that is not currently understood. Yes, we know enough about quantum mechanics (the mathematical formalism) to do calculations. The problem is that we then go and interpret what we see. That part cannot be tested by experiments.

For example, in certain interpretations of quantum mechanics it is believed that the wave function collapses to produce (or because of) the result we observed. Nobody really knows how this works. This is the measurement problem, which is currently a hot topic in quantum foundations.

But is this even science? How is this going to help us move forward? It occurs to me that these types of problems require us to step out of this struggle and get some distance from it. I said elsewhere that wisdom is the path to knowledge. Perhaps we need to get the metaphysics right before we will be able to get the physics right. We need to separate that which we can learn from a scientific approach from that which cannot be investigated scientifically.

Perhaps there is not such a clear cut distinction between those aspects of quantum physics that can and cannot be studied scientifically. However, it is not difficult to see where we are bound to waste much time with potentially limited or no advances.

In the following posts, I intend to address some specific aspects of the current impasse and how it impacts our current understanding. Although I’m not a fan of philosophy, some of these discussions may touch on some philosophical aspects of the topic – the metaphysics – in as far as it may show us the way.

Mopping up

The particle physics impasse prevails. That is my impression, judging from the battles raging on the blogs.

Among these, I recently saw an interesting comment by Terry Bollinger to a blog post by Sabine Hossenfelder. According to Terry, the particle physics research effort lost track (missed the right turnoff) already in the 70’s. This opinion is in agreement with the apparent slow down in progress since the 70’s. Apart from the fact that neutrino’s have mass, we did not learn much more about fundamental physics since the advent of the standard model in the 70’s.

However, some may argue that the problem already started earlier. Perhaps just after the Second World War. Because that was when the world woke up to the importance of fundamental physics. That was the point where vanity became more important than curiosity for the driving force to do research. The result was an increase in weird science – crazy predictions that are more interested in drawing attention than increasing understanding.

Be that as it may. (I’ve written about that in my book.) The question is, what to do about that? There are some concepts in fundamental physics that are taken for granted, yet have never been established as scientific fact through a proper scientific process. One such concept pointed out by Terry is the behaviour of spacetime at the Planck scale.

Today the Planck scale is referred to as if it is establish scientific fact, where in fact it is a hypothetical scale. The physical existence of the Planck scale has not and probably cannot be confirmed through scientific experiments, at least not with out current capability. Chances are it does not exist.

The existence of the Planck scale is based on some other concepts that are also not scientific facts. One is the notion of vacuum fluctuations, a concept that is often invoked to come up with exotic predictions. What about the vacuum is fluctuating? It follows from a very simple calculation that the particle number of the vacuum state is exactly zero with zero uncertainty. So it seems that the notion of vacuum fluctuations is not as well understood as is generally believed.

Does it mean that we are doomed to wander around in a state of confusion? No, we just need to return to the basic principles of the scientific method.

So I propose a mopping up exercise. We need to go back to what we understand according to the scientific method and then test those parts that we are not sure about using scientific experiments and observations. Those aspects that are not testable in a scientific manner needs to be treated on a different level.

For instance, the so-called measurement problem involves aspects that are in principle not testable. As such, they belong to the domain of philosophy and should not be incorporated into our scientific understanding. There are things we can never know in a scientific manner and it is pointless to make them prerequisites for progress in our understanding of the physical world.