in Miscellaneous

Level 3 thinking in physics – or – how to reach a mature understanding of any physics topic

“You do not understand an argument, until you’ve found the major flaws in it. For any problem complex enough to be interesting, there is evidence pointing in multiple directions. ”

@tylercowen

While there are many models that try to encapsulate how learning and understanding works, I recently came across one particular model that I keep thinking about and find extremely useful.

The model is a simple 3-level model and was proposed by Nat Eliason here.

The model describes remarkably well how I reached maturity in my thinking about different physics topics and since Nat didn’t mention physics, I want to discuss some examples below.

But first, a short summary of the model.

 

Level 1

Level 1 is called “Blind Ideology“. Everyone starts at this stage for any given topic. This stage is

“characterized by the wholesale adoption of the beliefs, attitudes, and lifestyles that were thrust onto you by your upbringing and environment. [….] Level 1 thinkers have an ideology they’re fixed to, and their blindness to it makes them throw out contrary opinions as heresy.”

A great example is diet. Here, Level 1 means that you eat what your parents taught you to eat, which in most cases is the standard Western diet.

Level 2

Level 2 is called “Chosen Ideology“. At this stage, people realize that the first best thing they were taught isn’t the best thing that exists and they become obsessed with another ideology. As Nat describes it

“If you know someone who believes in something and is annoying about it, they’re most likely at Level 2.”

We reach Level 2 after a “Moment of Clarity“. During such moments we realize that we have been driving with blinders on.

For the diet example above, Level 2 means that you become obsessed with something like Low-carb, Paleo, Veganism etc. At this stage, you are convinced that, for example, Paleo is the only way to go and every other way to eat is stupid.

Level 3

Finally, there is Level 3, which is called “Ideology Transcendence“. At this stage, we are able to sample the best bits from pre-packaged belief systems. At Level 3 we realize that no pre-packaged ideology is a perfect fit for us and we start developing our own. We start studying all ideologies that are out there and pick from each one only those parts that are of use for us.

The step from Level 2 to Level 3 is only possible through lots of Moments of Clarity. Only when we are exposed to lots of contrarian points of view, we can recognize the flaws in every pre-packaged belief systems. To reach Level 3 we must read books and articles that make us uncomfortable.

Regarding the diet example, Level 3 means that you recognize that different people respond differently to different diets. Everyone has different genes and therefore everyone has to experiment to find a diet that is a good fit. However, no pre-packaged diet can be a perfect fit for everyone.

A good test if you’ve already reached Level 3 are “Brake Lights”:

“When you react emotionally to information, any information, that’s a sign of Level 1 or Level 2 thinking. If you truly had a well-rounded stance on a topic and cared about enhancing your understanding of it, you would not react emotionally to anyone else’s opinion.”

 

It’s important to note that at Level 3 there is a “Strange Loop“. After enough time you will build an ideology of your own by picking the best stuff from other ideologies and adding something of your own. However, as soon as this happens you are again back at Level 2 since you are again following an ideology. Then, you must again search for flaws in your thinking and get exposure to contrarian points of view. In other words, Level 3 starts again. Level 3 is a stage of constant deliberate uncertainty.

The notion “Strange Loop” was coined by Douglas Hofstadter in his book “Gödel, Escher, Bach“:

“The “Strange Loop” phenomenon occurs whenever, by moving upwards (or downwards) through levels of some hierarchical system, we unexpectedly find ourselves right back where we started.”

In some sense this a miniature version of the whole scientific process. We can never know anything in the real world with 100% certainty. The only thing we can talk about is the level of confidence we have in a given theory, model or idea. Ultimately, today’s paradigm-shifting theory will become tomorrows standard theory and will again be replaced by another paradigm-shifting theory.

Nat discusses several other examples and most importantly ways to actively “level up”. It’s much better than this short summary and I highly recommend reading it.

But now, let’s discuss what all this means for physics.

Physics beyond Ideologies

Quantum Mechanics

  • Level 1 is the standard “Shut up and Calculate” approach that everyone learns in the lectures and standard textbooks.
  •  Level 2 thinking is becoming obsessed with, for example, “Bohmian Mechanics” or the Everretian “Many-Worlds interpretation”.
  • Level 3 thinking is realizing that none of these approaches is entirely correct and starting to develop your own way of thinking about quantum mechanics.

Gauge Symmetry

  •  Level 1 thinking is that gauge symmetry is a neat trick to derive the Lagrangian of the Standard Model and otherwise only necessary to prove renormalizability.
  • Level 2 thinking is becoming obsessed with the geometrical interpretation of gauge symmetry in terms of fiber bundles or with the idea that gauge symmetries aren’t fundamentally important after all but merely redundancies in our description.
  •  Level 3 is when you realize that gauge symmetries are indeed only redundancies, but carry a lot of physical meaning that isn’t captured by fiber bundles or the “neat idea” narrative.

Quantum Field Theory

  •  Level 1 is again the standard “Shut up and Calculate” approach that everyone learns in the lectures and standard textbooks. For quantum field theory this meany learning how to calculate Feynman diagrams and path integrals without caring about their meaning.
  •  Level 2 thinking is becoming obsessed with, for example, Supersymmetric Quantum Field Theory or String Theory.
  •  Level 3 thinking is realizing that none of the existing “beyond QFT” frameworks is the final answer. Maybe there are no quantum fields after all, since every time we took the field idea seriously we ended up with horribly wrong predictions (Monopoles, Strong CP violation,  Domain Walls etc.).

General Relativity

  •  Level 1 is the conventional narrative that in General Relativity there is no longer a gravitational field, but instead, gravity is merely a result of the curvature of spacetime.
  • Level 2 is the realization that you can turn this whole idea around and argue that the essence of general relativity is that there is no spacetime at all but only interacting fields. The only thing that exists are points where spacetime trajectories of field excitations meet. Only this way spacetime emerges. Another possible Level 2 understanding is “GR is the unique theory with no absolute object”, as coined James L. Anderson in his book Principles of Relativity Physics. (I actually have a friend who is really obsessed with this idea.)
  •  Level 3 is… I have no idea. I find the level 2 idea outlines above extremely cool and I guess this means I am stuck at level 2 for now. But if you know any articles that could help me improve beyond Level 2, please send them my way.

Some thoughts on how to level up in physics

After reading Nat’s essay I started thinking about how I could actively improve my learning process by taking the various 3 levels into account.

I started by assessing at what level I current am for various topics. (It turned out I’m still at level 1 or 2 for many physics topics).

Then I started to think about how I can get from Level 1 to Level 2. The crucial step here is recognizing that there is more than what we learn in lectures and the standard textbooks.

Level 2 ideas usually can’t be found in textbooks. Instead, they must be actively discovered. Often it’s just a side remark in a paper, book, blog post or at StackExchange that initiates the moment of clarity. Afterward comes a period of “going down the rabbit hole” where I try to trace any reference and comment on the alternative approach.

Finally, after enough research, I slowly realize that the alternative approach I became obsessed with is not the final answer. Level 3 thinking requires that I recognize that there is more than one reasonable idea of how to go beyond what we learned in lectures and textbooks.

To stay at Level 3 I must be constantly exposed to ideas that challenge my current beliefs. If I become too certain of a given idea I fall back to Level 2. Level 3 is uncomfortable and lonely.

To summarize: To level up you must read broadly. If you only stick to the books that your professor recommends you will stay at Level 1. Read books and articles by experts, read blog posts, read comments at StackExchange or at the PhysicsForums, read stuff by weird unknown guys. It doesn’t matter as long as they do not all repeat the standard story over and over again. As soon as some alternative approach sparks your interest it is necessary to dig deep and understand it from all possible angles. While it is extremely helpful to become obsessed during this phase, this obsession should always end after some time. At some point, it is always necessary to recognize that there is no universal pre-packaged answer.

P.S. I wrote a textbook which is in some sense the book I wished had existed when I started my journey in physics. It's called "Physics from Symmetry" and you can buy it, for example, at Amazon. And I'm now on Twitter too if you'd like to get updates about what I'm recently up to.

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