Heisenberg’s Uncertainty Principle

You ask me if an ordinary person could ever get to be able to imagine these things like I imagine them. Of course! I was an ordinary person who studied hard. There are no miracle people. It happens they get interested in this thing and they learn all this stuff, but they’re just people. There’s no talent, no special ability to understand quantum mechanics, or to imagine electromagnetic fields, that comes without practice and reading and learning and study. I was not born understanding quantum mechanics – I still don’t understand quantum mechanics! I was born not knowing things were made out of atoms, and not being able to visualize, therefore, when I saw the bottle of milk that I was sucking, that it was a dynamic bunch of balls bouncing around. I had to learn that just like anybody else. So if you take an ordinary person who is willing to devote a great deal of time and work and thinking and mathematics, then he’s become a scientist! —Richard Feynman

 

The Heisenberg’s Uncertainty Principle was formulated in 1927 by Werner Heisenberg. It states that you cannot determine the location as well as the impulse (the energy of the movement) of an entity with infinite precision. An interpretation of this principle is that there cannot be objective measurements insofar as measurements always influence the entity that one is measuring. This is especially an issue for smaller particles like electrons.

 

To understand this principle, it is important to understand how we perceive the world. A measurement is nothing but a form of perception or observation. In contrast to the ancient view that our eyes send out “seeing rays,” we do not perceive our environment directly but rely on light reflected from objects. In order for an object to reflect light, light has to be beamed at the object. When examining very small particles, we encounter the problem that the smaller the particle, the smaller the wavelength of light has to be in order to be reflected at all. But the smaller the wavelength of light, the more energy is required and the more the beam of light influences the particle.

 

We can determine the position of a particle with precision limited only by the technology currently available to us. But this determination could cause the particle to be slowed down or redirected in its course, destroying the information about the impulse of the particle. Likewise, one could measure the impulse of a particle by simply having it hit a screen; however, this destroys the information about the position of the particle (replacing it with the known position of the screen).

 

A good example is sound waves—the directed vibration of air molecules caused by a sound source. There is no way to determine the frequency or other properties of a sound wave by a single “snapshot picture” of the air. Even if one knew all the positions of the air molecules at a certain point in time, you would know nothing about how they vibrate. If you instead used a microphone and let the air molecules hit a membrane, you could get information about the whole soundwave and its frequency.

 

Revisiting Objective Perception

 

With this new knowledge about the inner workings of the physical work, it is time to reflect on our existing concepts. This reflection is not a violation of our philosophic principles established in the first place, quite the opposite: we refine our epistemology and ontology constantly in order to get a better view on reality.

 

So, what follows from our inability to measure location and impulse of entities with arbitrary precision? For the creation of concepts, this does not bother us because we omit the measurement anyways. We have to take a step back, though, from the idea that by simply building better measurement tools we could measure anything. The underlying problem simply is that we are part of the universe, so any action we take—including observing it by measurements—influences the universe. The consequence is that we cannot be omniscience. But as we have established in the first book, omniscience is not required in order to have an objective perception on reality (and vice versa, objective perception does not mean potential omniscience).

 

Something seems wrong, though. Can we really say that we know the properties of a particle if we cannot determine their position and impulse at the same time? Are entities like electrons or atoms really entities in the classical sense, similar to tiny pellets? Taking a look at atoms, we really cannot make a “photo” of an atom with its electrons, yet a very popular depiction is the core being surrounded by electrons:

(from https://de.wikipedia.org/wiki/Datei:Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg)

 

But this depiction does not reflect reality. Classical physics, with an entity-based philosophy, with a single particle (a negatively charged electron) orbiting the atom core (neutrons and positively charged protons), provides no explanation why the electron does not fall into the core. In quantum mechanics, there are no distinct electron particles but electron clouds around the nucleus based on the probability of where the electron could be. Ultimately, the point is that particles do not have a momentum or position. Heisenberg’s principle correctly identifies that position and momentum cannot be measured together. But it falsely implies that the principle merely addresses an issue of measuring hidden absolute quantities.

 

This leads to a problem with our definitions: concept creation involves making observations of reality, and omitting measurements in order to focus on the actual properties of an entity. But if we cannot make those measurements in the first place, they cannot be omitted either! Logically, it would follow that we cannot create concepts of particles in the (small) quantum world. But if we cannot create a concept based on entities for those small particles, what would that mean for our ontology?

 

In summary:

  1. Concept creation: Make observations and omit measurements.
  2. Small particles: Objective measurements cannot be taken.
  3. If no measurements can be taken, they cannot be omitted.
  4. From (1) and (3) follows that we cannot create a concept for these small particles.

 

Conclusion

 

In the Middle Ages, people discovered that our eyes do not send out “seeing rays” into the world and had to therefore go back to their original premises about human perception. With the discovery of quantum mechanics, we likewise need to go back and check our epistemological premises. Our journey through philosophy continues to the very edge of entity-based thinking, Western philosophy, and classical physics: can we build a bridge to process-based thinking, Eastern philosophy, and quantum mechanics? This will be the story of the following articles.

2017-09-23T21:16:52+00:00

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