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If you can’t explain something in simple terms, you don’t understand it

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Re: If you can’t explain something in simple terms, you don’t understand it

#191

Post by Retric »

xg15 wrote: post #180
Jach wrote: post #106

Earlier quoted context omitted.

A math formula is one of the objectively simplest ways of expressing something. But it's not easily understood unless you know the math well, thus violating Gruber's rule. Feynman was honest about this, because magnetism can be explained very simply, but not in any familiar way to things most people already know about. At least as good as math (and capturing the objective complexity better I think) is a working progr…

But I think that's the deeper point of the "if you can't explain it, you don't understand it": Sure, you can write down the equations, but then what exactly have you done? You wrote down some string of characters and showed that it can be derived from some other strings of characters by applying a series of arbitrary-looking rules. By itself, that doesn't tell anything. It's only when you manage the connect formula t…

QM for example has zero relationship with well known phenomena.

Re: If you can’t explain something in simple terms, you don’t understand it

#192

Post by pharrington »

Retric wrote: post #191
xg15 wrote: post #180

Earlier quoted context omitted.

But I think that's the deeper point of the "if you can't explain it, you don't understand it": Sure, you can write down the equations, but then what exactly have you done? You wrote down some string of characters and showed that it can be derived from some other strings of characters by applying a series of arbitrary-looking rules. By itself, that doesn't tell anything. It's only when you manage the connect formula t…

QM for example has zero relationship with well known phenomena.

Now I want to invent a hominid that intuits probability.

Re: If you can’t explain something in simple terms, you don’t understand it

#193

Post by ReidZB »

frahs wrote: post #155
jknoepfler wrote: post #68

This strikes me as raw arrogance. Complexity is intrinsic to many systems that are subject of expert study. 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. This is the sort of thing you'd believe if you were an arrogant 20-som…

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 yo…

> 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...

Re: If you can’t explain something in simple terms, you don’t understand it

#194

Post by timoth3y »

There is no reason to believe this statement is true, and the article doesn’t even try to make a case for it. It “feels” like it should be true, but the discussion is really just asserting the statement.

Skeptic: “I understand X. I’ve spent years working on it, and I’m recognized as an expert in the field. but I can’t explain X in simple terms.”

Believer: “Well, then you obviously don’t really understand it. Can you prove to me that you do"

Being able to explain things in simple terms is a skill in and of itself. Many people do not possess this particular skill, but that does not mean they are unable to understand any subject.

Re: If you can’t explain something in simple terms, you don’t understand it

#197

Post by DrJokepu »

imjustsaying wrote: post #196

So people who can't teach their own language to foreigners in simple terms don't understand their own language? I've witnessed dozen of people try and spectacularly fail at teaching their own language.

Yes. Being able to speak a language intuitively is not the same as understanding the mechanics of the grammar. For example, I don't believe that many native English people have any idea how "accusative and infitive" works, yet they use it every day.

Re: If you can’t explain something in simple terms, you don’t understand it

#198

Post by hahajk »

Jach wrote: post #106
squeaky-clean wrote: post #40

Earlier quoted context omitted.

A lot of people seem to be conflating the idea of explaining something to a layman, and explaining something using simple terms.

A math formula is one of the objectively simplest ways of expressing something. But it's not easily understood unless you know the math well, thus violating Gruber's rule. Feynman was honest about this, because magnetism can be explained very simply, but not in any familiar way to things most people already know about. At least as good as math (and capturing the objective complexity better I think) is a working progr…

Well an equation is certainly the more precise way of describing something, but not really the simplest. My most vivid memory of this is my Automata class; the instructor led with the equations before describing in plain language. Take push down automata as an example [1]. The equations are found in the formal definition, but the informal definition is much clearer.

[1] https://en.m.wikipedia.org/wiki/Pushdown_automaton

Re: If you can’t explain something in simple terms, you don’t understand it

#199

Post by jancsika »

This Feynman quote from the article is put in the wrong context:

> I really can’t do a good job, any job, of explaining magnetic force in terms of something else you’re more familiar with, because I don’t understand it in terms of anything else you’re more familiar with.

The article implies this is a case of the scientist expressing that he didn't understand a thing. But watching the video in full[1], one realizes he is saying something different:

"It's a force which is present all the time and very common and is a basic force.

[...]

I can't explain that attraction in terms of anything else that's familiar to you. For example if we say that magnets attract like as if they are connected by rubber bands I would be cheating you because they're not connected by rubber bands-- I should be in trouble if you soon ask me about the nature of the band. And secondly, if you were curious enough you would ask me why rubber bands tend to pull back together again, and I would end up explaining that in terms of electrical forces which are the very things that I'm trying to use the rubber bands to explain. So I have cheated very badly, you see."

In other words, for some phenomena the only simple examples are themselves instances of that same phenomena. So the only possible analogies are themselves merely tautologies.

I've noticed something less sweeping though similarly absurd with the internet. As more and more of people's daily lives depend on internet technologies, it becomes more difficult to find modern, simple examples for analogies that don't rely on similar internet technologies. So someone who wants to explain the wonders of packet switching compares it to long-distance telephone calls, but they then spend the bulk of that time explaining long-distance phone calls to people who have never used a wired phone.

1: https://www.youtube.com/watch?v=wMFPe-DwULM

Re: If you can’t explain something in simple terms, you don’t understand it

#200

Post by killjoywashere »

The author is not a student of physics and didn't go through Feynman's lectures. Some of the stuff Feynman said may sound like the droll wisdom of an ancient wizard to laymen, but if you've studied physics, it sounds more like a fun introductory confection. The layman hears genius, a journeyman hears the chef's description of this evening's specials.
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