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Have you ever 'taught' anyone anything? When you do, you'll probably get what Feynman was trying to say. Complexity is intrinsic. Just that as a teacher/guide/explainer, you have to gently guide the novices around enough to invoke a sense of curiosity that will drive the pupil to explore on their own. The task at hand here is to make things less overwhelming, not removing or ignoring complexity.

For every complex system, there is usually an underlying simpler, though not accurate, model that makes grasping the broader concepts easier.

> For every complex system, there is usually an underlying simpler, though not accurate, model that makes grasping the broader concepts easier

One doesn't stop at that model. (Feynman didn't.)

It's used as scaffolding, later torn down, to organize thoughts. By continuously proceeding downwards, in a fractal nature, filling in gaps, tearing and replacing where needed, the larger structure always stands ready to contextualise.

This helps hold the audience's interest. It also lets the mind, by itself, fill in gaps, promoting retention as well as pedagogical efficiency.

I have, and do. Physics 101, or in my case computer science 101 are not the world. Humans are gifted teachers (probably unique among animals in our instinct to simplify while teaching). I love distilling things down into teachable parts. It's hard, interesting work.

But I also do research, and I absolutely do not expect deeply technical topics like advances in aerospace engineering or gene regulation or cosmology to have "simple explanations" that I can understand. I accept that I won't understand them without years of effort, and I won't denigrate experts in those fields because of my limitations.

I tell people to come up with elevator pitches for complex work all the time, but I don't evaluate the quality of a thinker by the quality of their elevator pitch.

> "But I also do research, and I absolutely do not expect deeply technical topics like advances in aerospace engineering or gene regulation or cosmology to have "simple explanations" that I can understand."

There's a difference between explaining the entire topic and just giving you a very broad strokes approach to get you started learning the subject on your own. Nobody's having any delusions about summarizing a complex subject to a few sentences to substitute learning it the hard way, but if you can't give a very gentle explanation that can ease people in to the subject so they can get started by themselves, I would say that you don't fully understand the subject.

Also, I would add that this explanation is not universal at all. You have to be able to gauge your audience and adapt to what's most suitable.

My comment came across snarky. I apologize.

I agree cs 101 is not the world. I also agree some concepts cannot be simplified and it shouldn't.

My point was what you hinted towards when you say "distilling things down". My gripe is that most people that have taught or guided me have had no inclination to do that. I would have had a much smoother learning curve for it.

I also feel if there is a concept that can be taught by one person to another, it can be slowly be presented in increasing order of complexity than be presented all at once. That feeling of slowly building or adding complexity is underestimated and hard.

I think Feynman's statement is a wee bit over the top, and I will say that being able to teach complex things to novices is definitely an art and certainly one which I do not possess

I think it's partly motivational. There is definitely a level of understanding where it feels like you understand a concept, and then when you try to teach it to someone else, you realize when they ask basic questions that you don't understand it as deeply as you thought you did.

So, if you think you understand something, it's worth trying to explain it simply, so you can push your own understanding of the subject.

I think this is closest to what Feynman (I think) wanted to convey.

I like this idea

    > To tell someone who has devoted their career to
    > understanding a complex topic that they don't
    > understand their subject because they can't express
    > it in layman's terms without doing terrible
    > violence to the underlying phenomenon is ludicrous.

The article doesn't say you should be able to explain it to a layperson, but to a beginning student. This is a distinction that matters. A beginning student in your field should have enough preparation that what you need to explain is only the parts that relate to your particular area of expertise.

No one should devote their career to simply understanding a topic. If all you do is load someone else's work into your head, what value you are adding? A career is a mixture of learning as well as exploring and discovering new things. Explaining just the parts that are known is a much smaller order than transmitting the effort of your entire career into words.

Note also that Feynman isn't claiming you should be doing this all the time, but that you should be able to. I've been programming for about two decades and I've learned a ton (and yet still have even more left to learn). I'd like to believe that, yes, I could explain almost all of it to a beginning CS student or even a lay person.

They might not have the patience for me to build up all of the necessary structure from one simple piece at a time, but I think I could. After, that's how it got into my head in the first place. The parts that I couldn't do a good job decomposing and walking through are exactly the parts that I probably don't have a good handle on. (For me, networking and operating systems come to mind. I know some of the jargon, but I don't really know how it all works.)

I strongly disagree.

Complexity is real, but understanding means being able to conceptualize a system at such a high level that it becomes possible to convey the most important key ideas simply. This may involve some amount of over-simplification (which should be indicated if present) and will undoubtedly leave out a tremendous amount of detail, but the conceptual essence should be there.

The inability to do this is IMHO a sign of either lack of true and deep understanding or communication ability.

There are fields where nobody can really do this. These are fields that nobody truly understands yet.

Edit:

Let me give you an example. I had a bad (but typical) math prof in my very first calculus class who covered the board with examples and took us through how to differentiate a function. I was completely confused and stuck. Then I called my father on the phone and asked him and he told me "a derivative is a rate of change." Then I got the rest of calculus.

The prof had talked about slope but that wasn't conceptual enough. I needed "rate of change." That is the essence of calculus. It's the most important concept. Calculus deals with rates of change and the inverse (integrals). Once this concept was communicated the rest of calculus became possible to understand.

If you can't do that for a given area, you don't understand it or (as was the case with this math prof) are a poor communicator.

I strongly concur.

I suspect a so-called expert's ability to solve problems within a domain (i.e., how "expert" they are at that domain) would be a function of their ability to manipulate terms in that domain which to me is akin to their ability to those terms clearly.

I can't imagine someone easily solving problems within a domain wherein the terms they use are giant spaghetti balls of complexity. Anything can always be broken down into further levels of abstractions (or prove me wrong on that).

> This may involve some amount of over-simplification (which should be indicated if present) and will undoubtedly leave out a tremendous amount of detail, but the conceptual essence should be there.

I think the disagreement hinges on whether you believe the snippets from the GP post e.g. the "rods and cones" or caffeine examples are fundamentally valuable or not.

> There are fields where nobody can really do this. These are fields that nobody truly understands yet.

Curious what you would consider an example of such a field?

FWIW my anecdotal example of what I think the GP is complaining about... I read "The Elegant Universe": https://en.wikipedia.org/wiki/The_Elegant_Universe

It's a good book, and I enjoyed reading it. But over subsequent years I've had growing doubts over the true value of the "understanding" that it provided.

> Curious what you would consider an example of such a field?

The frontiers of physics always strike me this way. The names and explanations are incredibly strained and bizarre. This is probably the canonical example and is perhaps why The Elegant Universe doesn't quite achieve what it sets out to achieve.

Another one from my own academic past is "complexity theory" where hand-wavey concepts like "emergency" or "higher order causation" get thrown around with a lot of confusion. We can clearly see there's some "there" here, but I don't think we really understand what it all means yet. Put stuff together, interesting higher-order stuff happens, and so now let's create a combinatorial explosion of jargon around it. Publish or perish.

Finally "consciousness studies" or anything else semi-fringe probably counts. Again there's certainly some "there" there, but we don't even know the right questions to ask. Something is happening to matter that makes it wonder what's happening to it.

For me the "derivative is a rate of change" moment was when I was told that a limited integral is the area under the graph. It just never made sense till then.

? There's a difference between explaining something complex to a layman and explaining something complex in simple terms. You can always do the latter, and if you can't you don't understand the topic; this is a different exercise than trying to fit a topic into someone else's horizon of understanding, which may be thousands of simple building blocks behind.

As an arrogant 20-something year old, I disagree :P.

An important distinction to make here is whether you're teaching someone to intuitively reason about something or to logically calculate it precisely.

I think as long as someone grasps the basics of high school math and has a decent working memory, they should be able to learn how to calculate anything precisely given that you break it down into simple steps. If you don't know how to do that, you have no clue what you're doing.

Then there's intuitive reasoning. I think for most things, if you're familiar with a topic, you should be able to teach it in a way that makes sense. Of course there's exceptions -- some people are incredibly brilliant, but lack social awareness. I think that's the exception rather than the average case.

But not all topics are so easily reduced. There's probably some exceptions. The strongest that comes to mind is quantum computing. As many times as you can explain things like superdense coding, there's still a sense of "magic". Where the results of the math seem unnatural. And you go back through each step and try to figure out where things went weird. But each step is a logical progression from the beginning.

On that note, Michael Nielson's "Quantum Computing for the Determined" is one of the most well-taught courses I've found, and does a very good job of stepping the viewer through a very complicated topic. Michael Nielson clearly knows what he's doing :)

http://michaelnielsen.org/blog/quantum-computing-for-the-det...

> I think as long as someone grasps the basics of high school math and has a decent working memory, they should be able to learn how to calculate anything precisely given that you break it down into simple steps. If you don't know how to do that, you have no clue what you're doing.

Well, yes, if the only goal is computation. It doesn't take many instructions at all to be Turing-complete, and then you can compute everything a Turing machine can, which is lots of things.

That said, being able to calculate something can be very meaningless. You can try to do AES[1] by hand, if you'd like; it would be frustrating and very time-consuming, and then at the end of it you'll have gained effectively no understanding of its design or structure.

Using AES as a case study as well, one could explain the basic idea of encryption to a layman without too many troubles, but I can't imagine trying to explain anything about its operation or design to a layperson in a way that would make any sense at all.

[1] https://en.wikipedia.org/wiki/Advanced_Encryption_Standard#D...

I dunno. I learned more about light from [1] than anything else i'd ever read or saw. Am i an expert? hell no. I do have a far, far better handle on how lenses and mirrors work though. I think you'd be hard pressed to claim that either qed isn't that complicated, or, this lecture does a bad job of describing it.

Although, i would agree that some experts do a bad job of explaining things. They're still experts. I think you'd agree that non-experts don't really have a chance at explaining things.

[1]https://www.youtube.com/watch?v=eLQ2atfqk2c

that's arguing for the reverse of the rule, you can't explain something simply if you don't understand it. But that doesn't imply the reverse case.

I think it's meant at a higher level. This is one of the basic tenets of philosopher Ludwig Wittgenstein's ideas:

"The limits of one's language are the limits of one's world." It's controversial, but the concept being if you can't speak about it, you really can't know it fully. This gets very fuzzy when experiencing art or emotions, but there is a cold logic to it that I appreciate, too.

Nothing I do is intrinsically complex. It's just data processing. Copy a string from here, paste it over there.

Maybe, maybe, some times I'll do something clever.

Some times someone will have an insight, intuition. Like a market analysis. Or frame some useful questions for our recommenders.

Otherwise, all of the complexity that I encounter day-to-day is because of people's cognitive limitations. We make it hard. Misunderstanding, miscommunication, separation anxiety, dogma, arrogance, cya, whatever.

Being able to convey information in simple terms and pass along the depths of your understanding are two independent topics.

As an example, when we teach people how to fly a wingsuit, we essentially teach wingsuiting (which is a massively complex pursuit) as a set of nested arrays of increasing complexity.

For example, for a first jump course, the goals are as follows: - Exit safely - Demonstrate ability to navigate in-flight - Deploy

These are the most foundational aspects of flying a nylon dress out of an airplane.

After a few jumps, we'll add complexity to each of those, so to shift one point, it starts looking like:

- Exit in an unstable manner and gain stability in less than three seconds

In order to do that, you'll need to understand what causes a wingsuit to be stable, why it gets unstable, what happens when it gets unstable, and how to correct it. Additionally, you'll understand why I want you to do it in less than three seconds. However, at first, you just need to get out of the fucking plane. If I try to tell you all this extra shit you won't remember the foundational thing I need you to remember. You'll probably get unstable, you'll probably figure it out kinda, and you'll probably at some point deploy a parachute.

Teaching's hard.

I think your examples prove the opposite, that if you can explain something in simple terms than you do not necessarily understand it.

I do agree that poor communication skills are not a lack of understanding, however, not being able to explain something I thought I understood is a personal redflag.

from the zen of python:

If the implementation is hard to explain, it's a bad idea.

If the implementation is easy to explain, it may be a good idea.

I think you misunderstand what the author means by simple terms.

Everything can be talked about on different levels of abstraction, including ones which use metaphors or contain inaccuracies in order to create a jumping-off point for further learning.

If you understand something very well, you're able to use various levels of precision + abstraction in order to best communicate it to your audience. You can "play" with it, without getting confused or off-track. If you don't understand it well, this gets very hard.

I think this is true for teaching and mastery in general, and not just for teaching about science or complexity.

Understanding the fine details is one thing, but unless you can really communicate a synthesis or an analogy, it's impossible to really prove you understand something.

Nobody cares about a genius who understands something until he can really interact about the subject.

Humans work with communication. When you learn about something, you read about it and you process it. To see if you understand it, you must communicate it back. It's not really possible to guess how you brain just learned about something unless you ask that brain to reformulate it.

I care that the people at CERN can make a working LHC, not that they can communicate it to me succinctly (eg, in under 2 hours).

It's fine that it takes 150-300 hours of back-and-forth communication to transfer the ideas behind how it actually works. That seems like a reasonable amount of time to communicate a complex idea to a novice.

There's also layers of understanding:

The LHC bangs two rocks together hard to see what happens when they break.

The LHC use magnets to accelerate protons fast enough they break apart because it recreates conditions similar to the early universe.

etc.

"The LHC use magnets to accelerate protons" - That statement would really confuse someone with a basic knowledge of physics because static magnetic fields can't do work and hence can't accelerate particles.

The acceleration is actually done by electric fields produced in RF cavities.

But how do you really know if the LHC works? You need people to communicate with each other.

And do you really expect politics to raise funds for such a project if nobody can explain to them what they are doing?

I don't believe you'll get a better than "smash rocks, see what happens" understanding of what the LHC does without significant time invested in understanding.

That's okay: politicians don't actually need to know how it works, they need to know why they should build it -- which is a) something they have domain expertise in and b) a much easier question.

"To see if you understand it, you must communicate it back"

That's one option. You could also apply the knowledge and see if what you think you understand has resulted in a mental model from which you can make testable predictions that correspond to the real-world behavior of the modeled thing.

That's why there's peer review.

His point seemed to be that experts who don't know how to converse with non-experts aren't really expert enough to hold the title. If you don't know what concepts you had to use to learn the material, then how can you trust your conclusions?

It's sort of like saying that a mathematician who doesn't know how to prove their results to one who only knows the axioms doesn't fully understand their results.

I think it's meant to apply to a single, atomic concept that the audience is suitably prepared to understand. It couldn't be something like "how to build a car starting from a lump of steel" -- that would not be a single, atomic idea. "How anti-lock brakes work" might be a better idea to explain in simple terms.

Since you bring up James Joyce, I'd like to add that poets don't explain things in layman's terms.

May I propose, in contrast, that explaining is the art of simplifying the complex for others?

Coffee makes me more alert because it triggers a release of ATP.

I do agree it is arrogance.

A kid just told me "I know Python, I did the games." Facepalm.