Me and my shadow: quantum mechanics challenges the concept of personality

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

Why are you you? How do you know that you are a person with a unique character and way of thinking? Quantum mechanics advises us not to be so overconfident. It is possible that we are not all as different as we imagine.

Martin Guerr and the stolen identity

Did you know about Martin Guerre? This is a French peasant who once found himself in a strange and unpleasant situation. Martin lived in a small village. When the boy was 24 years old, his own parents accused him of stealing. Herr was forced to leave his home, leave his wife and son. Eight years later, the man returned to his native village, reunited with his family. Three years later, the family had three children.

Everything seemed to go on as usual. But a foreign soldier appeared in the village, who declared that he had fought with Martin Gerr in the Spanish army and that he had lost his leg in battle. Martin's family began to doubt whether their relative had returned home three years ago. After a long trial, it turned out that the identity of Guerra was "kidnapped" by the adventurer Arnault du Tilh. The real Martin did indeed undergo a leg amputation and was appointed to a sinecure at a monastery in Spain. However, the trial of the "identity thief" was so famous that the real Herr returned to his native village. The fate of the adventurer Arnaud du Thiel was sealed by a short death sentence. And Martin himself accused his wife of aiding the deceiver, not believing that a woman might not recognize her beloved husband.

This story excited the minds of writers and directors. Based on her motives, a film was shot, a musical was staged and even a TV series was shot. Moreover, one of the series "The Simpsons" is dedicated to this occasion. Such popularity is understandable: such an incident excites us, because it hurts to the quick - our ideas about identity and personality.

How can we be sure who a person really is, even the most dear one? What does identity mean in a world where nothing is permanent?

The first philosophers tried to answer this question. They assumed that we are different from each other in soul, and our bodies are just puppets. Sounds good, but science has rejected this solution to the problem and suggested looking for the root of identity in the physical body. Scientists dreamed of finding something at the microscopic level that would distinguish one person from another.

It's good that science is accurate. Therefore, when we say “something at the microscopic level,” we, of course, mean the smallest building blocks of our body - molecules and atoms.

However, this path is more slippery than it might seem at first glance. Imagine Martin Guerr, for example. Approach him mentally. Face, skin, pores … let's move on. Let's get as close as possible, as if we have the most powerful equipment in our arsenal. What will we find? Electron.

Elementary particle in a box

Herr was made of molecules, molecules are made of atoms, atoms are made of elementary particles. The latter are made "out of nothing"; they are the basic building blocks of the material world.

An electron is a point that literally doesn't take up any space at all. Each electron is determined solely by mass, spin (angular momentum) and charge. This is all you need to know to describe the "personality" of an electron.

What does it mean? For example, the fact that each electron looks exactly like any other, without the slightest difference. They are absolutely identical. Unlike Martin Guerr and his twin, electrons are so similar that they are completely interchangeable.

This fact has some rather interesting implications. Let's imagine that we have an elementary particle A, which differs from elementary particle B. In addition, we got hold of two boxes - the first and the second.

We also know that each particle must be in one of the boxes at any given time. Since we remember that particles A and B differ from each other, it turns out that there are only four options for the development of events:

• A lies in box 1, B lies in box 2;
• A and B lie together in box 1;
• A and B lie together in box 2;
• A lies in box 2, B lies in box 1.

It turns out that the probability of finding two particles at once in one box is 1: 4. Great, sorted it out.

But what if particles A and B are no different? What is the probability of finding two particles in the same box in this case? Surprisingly, our thinking unmistakably determines: if two particles are identical, then there are only three options for the development of events. After all, there is no difference between the case when A lies in box 1, B lies in box 2, and the case when B lies in box 1, A lies in box 2. So the probability is 1: 3.

Experimental science confirms that the microcosm obeys a probability of 1: 3. That is, if you replaced electron A with any other, the Universe would not notice the difference. And you too.

Sly electrons

Frank Wilczek, a theoretical physicist at the Massachusetts Institute of Technology and a Nobel laureate, has come to the same conclusion as we just did. The scientist considers this result not only interesting. Wilczek stated that the fact that two electrons are completely indistinguishable is the deepest and most important conclusion from quantum field theory.

A control shot is an interference phenomenon that "betrays" an electron and shows us its secret life. You see, if you sit and stare at an electron, it behaves like a particle. As soon as you turn away, it shows the properties of a wave. When two such waves overlap, they amplify or weaken each other. Just keep in mind that we mean not the physical, but the mathematical concept of a wave. They transfer not energy, but probability - they affect the statistical results of the experiment. In our case - to the conclusion from the experiment with two boxes, in which we got a probability of 1: 3.

Interestingly, the phenomenon of interference occurs only when the particles are truly identical. Experiments have shown that electrons are exactly the same: interference occurs, which means that these particles are indistinguishable.

What is all this for? Wilczek says that the identity of electrons is exactly what makes our world possible. Without this, there would be no chemistry. Matter could not be reproduced.

If there were any difference between the electrons, everything would turn into chaos at once. Their precise and unambiguous nature is the only basis for this world full of uncertainties and errors to exist.

Good. Let's say one electron cannot be distinguished from another. But we can put one in the first box, the other in the second and say: "This electron lies here, and that one is over there"?

“No, we cannot,” says Professor Wilczek.

As soon as you put the electrons in the boxes and look away, they cease to be particles and begin to exhibit wave properties. This means that they will become infinitely extended. As strange as it may sound, there is a possibility of finding an electron everywhere. Not in the sense that it is located at all points at once, but in the fact that you have a small chance of finding it anywhere if you suddenly decide to turn back and start looking for it.

It is clear that it is rather difficult to imagine this. But an even more interesting question arises.

Are electrons so tricky or the space they are in? And then what happens to everything that is around us when we turn away?

Hardest paragraph

It turns out that you can still find two electrons. The only problem is that you cannot say: here is the wave of the first, here is the wave of the second electron, and we are all in three-dimensional space. It doesn't work in quantum mechanics.

You have to say that there is a separate wave in three-dimensional space for the first electron and there is a second wave in three-dimensional space for the second. In the end, it turns out - be strong! is a six-dimensional wave that binds two electrons together. It sounds awful, but we understand that these two electrons are no longer dangling, no one knows where. Their positions are clearly defined, or rather, linked by this six-dimensional wave.

In general, if earlier we thought that there is space and things in it, then, taking into account the quantum theory, we will have to slightly change our representation. Space here is just a way to describe the interconnections between objects, such as electrons. Therefore, we cannot describe the structure of the world as the properties of all the particles taken together that make up it. Everything is a little more complicated: we have to study the connections between elementary particles.

As you can see, due to the fact that electrons (and other elementary particles) are absolutely identical to each other, the very concept of identity crumbles to dust. It turns out that dividing the world into its components is wrong.

Wilczek says that all electrons are identical. They are a manifestation of one field that permeates all space and time. Physicist John Archibald Wheeler thinks differently. He believes that initially there was one electron, and all the others are just traces of it, permeating time and space. “What nonsense! - you can exclaim in this place. "Scientists are fixing electrons!"

But there is one but.

What if it's all an illusion? The electron exists everywhere and nowhere. He has no material form. What to do? And what then is a person who consists of elementary particles?

Not a drop of hope

We want to believe that each thing is more than the sum of its constituent particles. What if we removed the electron's charge, its mass and spin and got something in the remainder, its identity, its "personality". We want to believe that there is something that makes an electron an electron.

Even if statistics or experiment cannot reveal the essence of a particle, we want to believe in it. After all, then there is something that makes each person unique.

Suppose there would be no difference between Martin Gerr and his double, but one of them would smile quietly, knowing that he was the real one.

I'd like to believe in it very much. But quantum mechanics is absolutely heartless and will not let us think about all sorts of nonsense.

Don't be fooled: if the electron had its own individual essence, the world would turn into chaos.

OK. Since electrons and other elementary particles do not really exist, why do we exist?

Theory one: we are snowflakes

One of the ideas is that there are a lot of elementary particles in us. They form a complex system in each of us. It seems that the fact that we are all different is a consequence of how our body is built from these elementary particles.

The theory is strange, but beautiful. None of the elementary particles has its own individuality. But together they form a unique structure - a person. If you like, we are like snowflakes. It is clear that they are all water, but the pattern of each is unique.

Your essence is how the particles are organized in you, not what exactly you are made of. The cells in our body are constantly changing, which means that the only thing that matters is structure.

Theory two: we are models

There is another way to answer the question. American philosopher Daniel Dennett suggested replacing the concept of "thing" with the term "real model". According to Dennett and his followers, something is real if its theoretical description can be duplicated more succinctly - in a nutshell, using a simple description. To explain how this works, let's take a cat as an example.

So, we have a cat. Technically, we can recreate it on paper (or virtually) by describing the position of each particle of which it is composed, and thus draw up a diagram of the cat. On the other hand, we can do differently: just say "cat". In the first case, we need huge computing power to not only create an image of a cat, but also, say, make it move, if we are talking about a computer model. In the second, we just need to take a deep breath and say: "The cat walked around the room." The cat is a real model.

Let's take another example. Imagine a composition that includes the left earlobe, the largest elephant in Namibia, and the music of Miles Davis. It will take a lot of time to create this object computationally. But the verbal description of this fantastic monster will also take you the same amount. It will not work to shorten, to say in two words, too, because such a composition is unreal, which means it does not exist. This is not a real model.

It turns out that we are just a momentary structure that appears under the gaze of the beholder. Physicists add fuel to the fire and say that perhaps in the final it will turn out that the world is made of nothing at all. For now, it remains for us to point at each other and the world around us, describing everything in words and distributing names. The more complex the model, the more we have to compress its description, making it real. Take, for example, the human brain, one of the most complex systems in the universe. Try to describe it in a nutshell.

Try to describe it in one word. What happens?