The problem with the measurement problem

It is not really a topic I want to discuss. In fact, I don’t think it is worthy of including under my Demystifying Quantum Mechanics series. However, since even physicists don’t seem to get it, it is necessary to clarify a few things.

So the argument seems to go that even of one were to consider a completely mixed quantum states with equal probabilities for different outcomes then a measure would convert this mixed state into one with only one outcome and zero for all other outcomes. This transformation is then interpreted as a quantum collapse and the fact that this process is not understood is called the measurement problem.

The problem with this interpretation of the situation is just that: it is an interpretation. So it falls under the general topic of interpretations of quantum mechanics. Currently, there are no known experimental conditions that can distinguish between different interpretations of quantum mechanics. As such it is not physics, because it is not science. It falls under philosophy. As a result, it would not be possible to solve the so-called measurement problem.

Just in case you are wondering whether this measurement scenario can be interpreted in any other way that does not involve collapse, the answer is yes. The obvious alternative is the Many World interpretations. In terms of that interpretation the mixed quantum state describes the different probabilities for all the different world in which measurement are to be performed. If one would restrict the quantum state to any one of these worlds (or realities) then it would have 100% probability for a specific outcome even before the measurement is performed. Hence, not collapse and no measurement problem.

So, yes indeed, the measurement problem is a pseudo-problem. It is not one that can (or need to be) solved in physics.

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What is your aim?

The endless debate about where fundamental physics should be going, proceeds unabated. As can be expected, this soul searching exercise includes many discussions of a philosophical nature. The ideas of Popper and Kuhn are reassessed for the gazillionth time. Where is all this leading us?

The one thing I often identify in these discussions is the narrow-minded view people have of the diversity of humanity. Philosophers and physicists alike, come up with all sorts of ways to describe what science is supposed to be and what methodologies are supposed to be followed. However, they miss the fact that none of these “extremely good ideas” have any reasonable probability to be successful in the long run.

Why am I so pessimistic? Because humanity has the ability to corrupt almost anything that you can come up with. Those structures and systems that exist in our cultures that actual do work are not the result of some “bright individuals” that decided on some sunny day to suck some good ideas out of their thumbs. No, these structures have evolved into the forms that they have today over a long time. They work because they have been tested over generations by people trying to corrupt them with the devious ideas. (It reminds me that cultural anthropology is, according to me, one of the most underrated fields of study. The scientific knowledge of how cultures evolve would help many governments to make better decisions.)

The scientific method is one such cultural system that has evolved over many centuries. The remarkable scientific and technological knowledge that we posses today stand as clear evidence of the robustness of this method. There is not much, if anything, to be improved in this system.

However, we do need to understand that one cannot obtain all possible knowledge with the scientific method. It does have limitations, but these limitations are not failing of the method that can be improved on. These limitations lie in the nature of knowledge itself. The simple fact is that there are things that we cannot know with any scientific certainty.

What is your reward?

So, the current problem in fundamental science is not something that can be overcome by “improving” the scientific method. The problem lies elsewhere. According to my understanding, this problem has one of two possible reasons, which I have discussed previously. It is either because people have lost their true curiosity in favor of vanity. Or it is because our knowledge is running into a wall that cannot be penetrated by the scientific method.

While the latter has no solution, the former may be overcome if people realize that a return to curiosity instead of vanity as the driving force behind scientific research may help to adjust their focus to achieve progress. Short term extravagant research results do not always provide the path to more knowledge. It is mainly designed to increase some individual’s impact with the aim to obtain fame and glory. The road to true knowledge may sometimes lead through mundane avenues that seem boring to the general public. Only the truly passionate researcher with no interest in fame and glory would follow that avenue. However, it may perhaps be what is needed to make the breakthrough that would advance fundamental physics.

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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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Wisdom is the path to knowledge

As a physicist, I cherish the freedom that comes with the endeavor to uncover new knowledge about our physical world. However, it irks me when people include things in physics that do not qualify.

Physics is a science. As a science, it follows the scientific method. What this means is that, while one can use any conceivable method to come up with ideas for explaining the physical world, only those ideas that work survive to become scientific knowledge. How do we know that it works? We go and look! That means we make observations and perform experiments.

That is the scientific method. It has been like that for more than a few centuries. And it is still the way it is today. All this talk about compromising on the basics of the scientific method is annoying. If we start to compromise, then eventually we’ll end up compromising on our understanding of the physical world. The scientific method works the way it works because that is the only way we can know that our ideas work.

Some people want to go further and put restrictions on how one should come up with these ideas or what kind of ideas should be allowed to have any potential to become scientific knowledge even before it has been tested. There is the idea of falsifiability, as proposed by Karl Popper. It may be a useful idea, but sometimes it is difficult to say in advance whether an idea would be falsifiable. So, I don’t think one should be too exclusive. However, sometimes it is quite obvious that an idea can never be tested.

For example, the interior of a black hole cannot be observed in a way that will give us scientific knowledge about what is going on inside a black hole. Nobody that has entered a black hole can come back with the experimental or observational evidence to tell us that the theory works. So, any theory about the inside of a black hole can never constitute scientific knowledge.

Now there is this issue of the interpretations of quantum mechanics. In a broader sense, it is included under the current studies of the foundations of quantum mechanics. A particular problem that is much talked about within this field, is the so-called measurement problem. The question is: are these scientific topics? Will it ever be possible to test interpretations of quantum mechanics experimentally? Will we be able to study the foundations of quantum mechanics experimentally? Some aspects of it perhaps? What about the measurement problem? Are these topics to be included in physics, or is it perhaps better to just include them under philosophy?

Does philosophy ever lead to knowledge? No, probably not. However, it helps one to find the path to knowledge. If philosophy is considered to embody wisdom (it is the love of wisdom after all), then wisdom must be the path to knowledge. Part of this wisdom is also to know which paths do not lead to knowledge.

It then follows that one should probably not even include the studies of foundations of quantum mechanics under philosophy, because it is not about discovering which paths will lead to knowledge. It tries to achieve knowledge itself, even if it does not always follow the scientific method. Well, we argued that such an approach cannot lead to scientific knowledge. I guess a philosophical viewpoint would then tell us that this is not the path to knowledge after all.