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

http://kottke.org/17/06/if-you-cant-explain-something-in-simple-terms-you-dont-understand-it

by daschaefer • 9 years ago

517 226 9 years ago

blakesterz• 9 years ago

Kottke's one of the very few blogs I've been reading for what seems like forever. He's still doing good work. Recently he's been trying membership, which I've not seen on a site like his anywhere else.

zerr• 9 years ago

No. The teaching ability is a completely different dimension, orthogonal to other skills/knowledge you have.

scandox2• 9 years ago

In job interviews I always zone in on the most complicated thing someone has worked on and then ask them to explain it to me. Often a thesis or a project or a large system or something low level to do with OS features etc...

It is amazing how rarely people can get it across to me in basic terms. In fact even the idea of breaking it down into non technical concepts seems to be surprising and alien to many people.

I really admire those who can.

lcnmrn• 9 years ago

I fail all interviews when I explain complex things in simple terms. Must be some correlation here.

shas32• 9 years ago

This has happened to me several times (not always in interviews). Especially when someone asks about machine learning and I start the explanation with regression, they get pissed. Nothing shows that you are trying to jump on a bandwagon than expecting needless complexity in explanations.

scandox2• 9 years ago

It's only one way to approach things. Many good people are not great explainers. However, I do find a willingness to try and get down to first principles a good sign. I only take it badly when people seem unable to think outside their expertise, or seem unaware of the layers above and beneath the particular strata they work within.

ivanbakel3• 9 years ago

The problem I find with this outlook is that it takes technical terms being jargon at face value. If you can't fall back on progress in language which allows you to express more complex ideas, you're not going to reach the same depth of understanding in simpler words without it taking a lot longer anyways - with most of your time spent reestablishing what you just threw out the window.

If you rehash it in smaller words, just by information density alone, aren't you guaranteed to be losing some detail?

godzillabrennus• 9 years ago

Explaining a concept doesn't need to be done with complex technical terms. Analogies are sufficient.

Executing on a concept using complex technology requires complex technical terms.

adrianratnapala• 9 years ago

It depends on the concept.

ivanbakel is not making some blanket claim that things always require complex technical terms. He is just saying that language -- including field-specific jargon -- evolves so that people steeped in the language can explain things to each other.

The clearest example of that how hard it is to decypher popular articles about quantum mechanics. Here, even when explaining concepts at a skin deep level, stories they tell are utterly inadequate if not misleading.

That's because even the basic concepts of QM are ones from linear algebra. And is shy Feynman was a sometimes devotee of the "shut up and calculate" school of interpretation.

jlg234• 9 years ago

If you rehash it in smaller words, just by information density alone, aren't you guaranteed to be losing some detail?

Of course, but when explaining something to another person, one should strive to optimize for being understood, not for the highest information density.

ivanbakel3• 9 years ago

But then what does it mean to be understood?

If you skip out the part of the analogy where you actually return to the complex terminology you're simplifying, you haven't produced understanding - you've only made a just-so story which is a reflection of the reality, not a justification for it.

BurningFrog• 9 years ago

This discussion really needs a concrete example.

jmileham• 9 years ago

But explaining something in simple terms is a necessary step to teaching the concept. Only once the concept is understood can you put a name to it and keep climbing the ladder of abstraction. This article doesn't devalue proper terminology, it values fluency with abstractions.

samuell• 9 years ago

This. I tend to think a key to really understanding something, is the ability to put that "something" in to contexts at a wide variety of abstraction levels.

That's what I hated the most with uni: Some professors could write 10 blackboards full of formulae, but could hardly put together a few words to explain what we were actually doing. Unsurprisingly, I don't remember much from these lectures. Fortunately that is not all professors, but it worries me how large a percent of them were like this.

usuallybaffled• 9 years ago

Maybe a refinement of this approach is to FIRST explain in simple terms to establish basic understanding and SECOND going deeper with technical jargon.

scott_s• 9 years ago

"Education is a series of small lies." Spoken by my intro to computer engineering professor, upon telling us that most real processors actually have some ternary logic.

The notion here is that educating beginners about a subject is different from communication between experts. Yes, experts use jargon because it is more efficient. But, the notion here is that if you truly understand something, you should be able to find a way to explain it to a non-expert, building up from words and concepts they already understand. And, further, if you can't do that, then perhaps your understanding is not as deep as you thought it was.

Cyph0n3• 9 years ago

most real processors actually have some ternary logic

Was he referring to the Z state? If so, it's not really ternary logic but rather a "no result" state for cases where there is a control signal involved (e.g., in a tri-state buffer).

ythn• 9 years ago

If something is too complex to be explained to a college freshman, it might be time for a paradigm shift to simplify (I.e. Ptolemaic astronomy vs heliocentric)

Algebra and calculus were one bleeding edge research that only the elite understood, now kids are learning it in middle school.

cle• 9 years ago

If you rehash it in smaller words, just by information density alone, aren't you guaranteed to be losing some detail?

Yes, but knowing which information you can lose is why it is said that you don't understand it until you can explain it. Explaining it in simple terms forces you to over-simplify, and then you have to pick which information is important and which isn't...and doing that requires a deep understanding of the subject (and your audience).

ikeyany• 9 years ago

You have a knack for explaining "explaining something in simple terms" in simple terms. Kudos.

cortesoft• 9 years ago

If you can't re-write it in assembly, you don't know how it works!

WhoBeI• 9 years ago

Well, yeah, but the technical detail doesn't have to remain low. When you first explain something to someone you keep it simple so that they get the broad picture, you use analogies and what not. As they learn you can start introducing more and more detail.

It's about explaining in a way the recipient can understand so "simple terms" becomes "terms your recipient can understand".

SilasX• 9 years ago

It's not a fail if you use jargon. It's a fail if you can't explain the jargon.

startupdiscuss• 9 years ago

This is generally true but I will add one wrinkle.

And there are three kinds of explanation:

1. visual

2. mathematical

3. linguistic

So sometimes, you understand something visually, or mathematically, but you are forced to put it into verbal terms (say, over a text only channel, or voice), and then you may seem not to be able to explain it even though you understand it.

darkerside• 9 years ago

I love this distinction. I've heard the headline stated before, and even if not directed at me, I find the very idea irritating and even a bit offensive. It's not necessarily that I don't understand it, it's that I can't prove to you that I understand it.

Next time I see this concept in action, maybe I'll suggest alternate methods of "explaining".

specialist3• 9 years ago

I first learned about The Big Triangle from Scott McCloud's "Understanding Comics".

http://scottmccloud.com/4-inventions/triangle/index.html

http://homes.chass.utoronto.ca/~mfram/Media/0505-UC-triangle...

Filed under "I believe, but cannot prove": The three-way tension is a recurring pattern.

When trying to understand new things, I often try to reframe things as a triangle. When pondering intractable problems, I favor three-way solutions. Some quick examples from memory...

Project management: time, money, scope.

aka Quality: Fast, good, cheap.

US Govt balance of power: Executive, Congress, Judiciary

Language design: imparative, declarative, functional

Pop music: harmony, melody, lyrics

thanatropism• 9 years ago

(A name for the three-way tension you will find a lot: trilemma.)

If you have to budget something, it becomes a soft trilemma: I have 24 hours for work + leisure + sleep, so any given combination will be a point inside a triangle whose vertices are (0, work), (0,leisure), (0, sleep). This structure is called a (2-)simplex.

BTW: a regular dilemma (should I spend or save) is a 1-simplex, and is a simple linear combination asave + (1-a)spend.

Now, this is fun for two reasons:

- You can have (n)-lemmas (i.e. n-fold tradeoff structures) that are modeled as (n-1)-simplices. Actually useful: you can do statistical inference on simplices using the Dirichlet distribution.

- A simplicial complex (basically, a set of simplices) can be used to build topological spaces part by part. This kind of maths (algebraic topology) is a whole "south part of the mountain" climb towards abstract mathematics that bypasses a lot of Cantorian handwringing on the ultra-local structure of topology. Instead, you're computing stuff from the get go -- and indeed one of the emerging machine learning techniques goes precisely from building a simplicial-like complex from data and computing characteristics of its topology.

octref• 9 years ago

Or to quote PG's Write Like You Talk[0]:

And in my experience, the harder the subject, the more informally experts speak. Partly, I think, because they have less to prove, and partly because the harder the ideas you're talking about, the less you can afford to let language get in the way.

Informal language is the athletic clothing of ideas.

[0] http://www.paulgraham.com/talk.html

simplicio• 9 years ago

Eh, I suspect part of the reason is that once a topic crosses a certain level of difficulty, trying to convey an exact explanation for it in a reasonable amount of time becomes impossible and experts just fall back on analogies and hand-waving.

I'm a physicist, and if you asked me to explain Newton's laws or classical thermodynamics to someone, I could probably give them a reasonably complete overview in a few hours. And in doing so I'd probably introduce and explain some jargon (entropy, derivatives, etc) along the way to make it easier.

On the otherhand, if you asked me to explain Quantum Field Theory or General Relativity in the same time, I'd basically just give up and throw out some friendly but inexact analogies about stretched rubber sheets and the like, and hope the walked away with some vague sense of the outlines of the subject.

vacri• 9 years ago

Meh, that's a cop-out. "You don't need complex sentences to express complex ideas." and "They don't use more complex sentences, just different words"? It's pretending that the complexity in the language lives only in the grammar, and not the jargon. Think of it this way: if spoken language gets more informal in terms of sentence structure the harder the topic, that means that the easier the topic, the more complex the sentences.

I think PG has confused the informality people have when they have a common understanding with something else. Do you really think that a pair of experienced mechanics in an auto shop discussing a basic repair are going to be using more formal language? Turn one of the mechanics into an apprentice and consider the same discussion.

freddref2• 9 years ago

Feynman also said:

"Hell, if I could explain it to the average person, it wouldn't have been worth the Nobel prize." [1]

Showing a limitation of the maxim or Feynman's hubris?

[1] https://en.wikiquote.org/wiki/Richard_Feynman

moomin2• 9 years ago

Listening to Feynman talk about magnetism fails to answer that question definitively one way or the other.

But seriously, if you can't explain what a complex-valued "probability" is to a layman, apparently you don't understand quantum mechanics?

freddref2• 9 years ago

It might have been hubris at the time he got the prize, but later he felt different about it:

https://www.youtube.com/watch?v=AEUcmKDaklY

fnordfnordfnord2• 9 years ago

I assume this is the bit of video you're referring to?: https://www.youtube.com/watch?v=wMFPe-DwULM

azag0• 9 years ago

Some parts of physics might stretch the ELI5 to its limits. I like to explain science to my non-science friends, but I'm always hitting the issue that parts of the specialized knowledge become intuitive, and then it's difficult to go back. Say, my understanding of how electrons behave in matter is a category on its own (let's call it quantum), and it's difficult to translate to common terms.

bdamm• 9 years ago

The more I try to learn physics, the more I need to see the mathematics to understand the ideas. Without the math, I don't believe it is possible to break beyond the surface 'armchair' level of understanding.

squeaky-clean2• 9 years ago

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

coldtea3• 9 years ago

That's because those things are inherently tied. It's not about taking your time and making the layman an expert to understand some hard topic. It's about being able to relate it to them in simple terms.

Obviously, if you use the "hairy" physics etc terms, then the layman wont understand your explanation, because he is not familiar with them.

sh8710• 9 years ago

Unfortunately, that is what is expected more commonly these days where the audience being presented to a.k.a layman aren't users or domain experts or people who know whats going on. They're management "experts" tasked with getting "resources" to "get things done".

I've seen people from my domain making ridiculous, inaccurate analogies and oversimplify to hide the inherent challenges that a task usually involves. And they get away with that because they aren't the ones actually building the product. They just have to sell it. And the one's they are selling to aren't/won't be using the product either, they will tell someone else to use it.

Jach2• 9 years ago

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 program. "What I can't program, I don't understand."

When people ask for a simple explanation, they usually expect it to be easy for them too, because we all want simple and easy at the same time, even though only one of those is objective. If your reply to "how do magnets work?" is to start by writing down Maxwell's equations, you're gonna get crap for it, but someone who uses the fake rubber band analogy will be well received. But who really understands magnetism better?

coldtea3• 9 years ago

It's not just some hard physics that have trouble with the ELI5 / "should be able to explain it" concept.

This is also true for literature, poetry, non-analytical philosophy etc. And there the challenges are not about the complexity of the subject, but about its subtlety, and how one needs historical context and/or certain life experiences (or even proclivities) to be able to grasp a particular piece of work.

rocqua• 9 years ago

It's not so much life experiences, but prior knowledge and familiarity.

Taking mathematics as the operative example. A lot of deep theorems are trivial when you fully understand all relevant definitions. These proves cannot be stated 'in simple terms' because it took a stack of non-simple definitions to even formulate such a theorem.

Explaining the entirety of the stack gets hard when the stack gets deep. For example, a lot of math gets really hard to explain when the concept of the real numbers being 'uncountably infinite' whilst the rationals are 'countably infinite' isn't obvious.

cxromos• 9 years ago

Neither if he was speaking about Quantum Mechanic. Feynman probably paraphrasing Bohr: "If you think you understand quantum mechanics, you don't understand quantum mechanics."

lymitshn• 9 years ago

In one of his books he told this story as follows, a cab driver watched him on TV and said to him "I cant believe you actually tried to explain what did you found." Then Feynman said "Well, what would you say?" Cab driver "If i could explain it in 2 min. then it would not be worthy." Afterwards Feynman used that line. I might be wrong though, but pretty sure he told a story like this.

Animats2• 9 years ago

Not hubris. Feynman won the Nobel Prize in physics in 1965. Here's his Nobel Prize lecture.[1] This gives some insight into how he thought.

[1] http://www.nobelprize.org/nobel_prizes/physics/laureates/196...

stcredzero• 9 years ago

I run into this all of the time when explaining what I'm doing at work as a programmer. It's not that I couldn't explain why my merging workload increased due to the increased code collisions from my coworkers working in the same files, and how dividing my current assignment in two so I could check in code would reduce this. It's doing that in a normal conversation under time and attention constraints which is the problem.

dtashima5• 9 years ago

In the workplace, there is also the problem of coworkers' (managers in particular) desire to listen to you explain it.

dtashima5• 9 years ago

Well he made that statement in 1965, and then wrote QED, which is a layman's explanation of his Nobel Prize work, in 1985. So perhaps he set out to prove himself wrong.

QED does explain quantum electrodynamics without any calculus or other math (for example, he uses imaginary clocks as a way to explain wave interference), but I think if the average person read it they wouldn't walk away with even a partial understanding of it.

cestith2• 9 years ago

I don't see this as evidence the other statement is false. If it was something he understood well enough at the time he was earning the prize, it wouldn't have been groundbreaking work worthy of the prize. Gaining that understanding or paving the way for that understanding is what's prize-worthy.

dragonwriter• 9 years ago

If one assumes that things at the edge of human understanding and thus most worthy of such a prize are understood only incompletely by those who understand them best, it is both consistent with Feynman's maxim and not at all a sign of hubris.

eksemplar• 9 years ago

They are both right. Something's can't be dumbed down enough to explain to everyone, but you can always explain the concepts. An example could be comparing an interface to a chocolate cookie recipe, when explaining it to your grandmother.

She'll still have no idea what an interface actually is, but she'll have a good grasp of the concept.

wddps• 9 years ago

Why is this true? Can someone explain it to me?

simlevesque• 9 years ago

In french we have a saying which translates to: whatever is well conceived is clearly said... and the words to say it flow with ease

ComputerGuru• 9 years ago

Ce qui est bien pensé se dit clairement ?

Edit: nevermind. I was way off.

Ce qui se conçoit bien s'énonce clairement, et les mots pour le dire arrivent aisément.

bryanrasmussen• 9 years ago

Or maybe you are just a really bad communicator.

sh8710• 9 years ago

Everyone was born a bad communicator. Some evolve into good ones some don't. Its an acquired skill.

arto• 9 years ago

Counterpoint from Feynman himself:

https://www.youtube.com/watch?v=MO0r930Sn_8

sh8710• 9 years ago

This is an interesting logic fallacy here. Consider this example.

Monkey eat => Monkey live.

Monkey live => Monkey eat.

Monkey not eat => Monkey not live.

Monkey not live => Monkey not eat.

Here "=>" is used as in "implies"/"because". The last statement is weird. There are more ways for monkey to "not live" than to "not eat".

Not being able to explain does not imply not being able to understand. Not understanding surely implies not being able to explain.

Correlation, Causation, get it ?

tgb2• 9 years ago

"implies" and "because" are not equivalent. For example, "x is positive implies x^2 is positive" is true but "x is positive because x^2 is positive" is false.

sh8710• 9 years ago

exactly what I was trying to point out. It came out wrong I guess.

A statement like "if not a, then not b" is not applicable unless a "implies" b and a "is because of" b.

Correct me if I got it all wrong somehow.

mikebenfield• 9 years ago

I think this idea is basically nonsense. Some things are complicated. To "explain" them in simple terms you necessarily leave out a lot of information. If all that information isn't crucial to the core idea, maybe that's worthwhile. But sometimes that information is crucial.

Some people look at advanced mathematics or physics and wonder why it has to be so complicated and so full of jargon. It's complicated because it is. The jargon, believe it or not, is mostly an attempt to make it easier to communicate. It would be very, very difficult to wade through these ideas without introducing new words with precise definitions.

Then again, John von Neumann said, "In mathematics you don't understand things. You just get used to them." So maybe the title is true for trivial reasons after all.

irrational• 9 years ago

Remember that repetition is the heart of learning. If you want someone to understand Relativity to the same degree Einstein understood it, you don't start with the math. You start with an analogy (which obviously doesn't match reality). Once they understand that you can add more analogies (maybe about just parts of Relativity). Eventually you build up from parts to the whole and from broad analogies to specific details. Over the years this is happening you will be gradually introducing shortcuts and jargon. But, only a master of the subject can explain a complex topic in simple terms. I can't tell you how many times my children have asked me a question about something I thought I knew, but once I started trying to explain it in terms they would understand I realized that I really didn't understand what I thought I understood. But if I spent a little bit of time reading up on the subject again then I found that I could explain it to them in such a way that they could correctly explain it back to me.

outworlder2• 9 years ago

It's not nonsense. You are forgetting a very important detail: "explaining".

He was not talking about writing a research paper on the simplest possible terms. Rather, about "explaining" a subject. When we are explaining, we always have to deliberately omit details to get the basic idea across, so that the other person can form the initial mental image. Sometimes we also have to resort to metaphors and comparisons from entirely different fields, or relate them to real world concepts.

Once that is done, then the lengthily process can begin on improving the fit of that mental image to the subject. This will require more explanations, more focused, in a different level of detail.

Case in point: dimensions higher than three. Most people cannot conceive what the heck a tesseract is, or why it is usually drawn the way it is. But then you can tell them to watch Feymann's Flatland scenario, and they will be able to understand the basic concept.

Are they mathematicians now? Hardly. But now they have some understanding on the subject which they did not have before, even if it is on a very high level. And can try to absorb more details, if so inclined.

Sacho• 9 years ago

Er, they may be left with a warm and fuzzy feeling that they have some "understanding", but let get them to do some multidimensional analysis and see how they do. The meaning of "explaining" seems just as elusive as the "simple explanations" themselves - once you've heard such a "simple explanation" and have a feeling that you now understand more than you do, what is the objective difference between you-before and you-now? It's my experience, and several professors have confided the same, that the "simple explanations" give students a nice feeling that they "get it", up to the point where they actually try to apply the knowledge and fail miserably. Maybe the explanation then wasn't really "simple", but now we're just shifting the goalposts further into epistemology.

I would tentatively agree that there is a skill which allows you to break down complex subjects into digestible chunks, but that usually depends a lot on the student as well as the teacher(e.g. some people are good at following metaphors, others learn very well from repeated examples, etc), but the outright statement in the topic suggests that there is no such thing as irreducible complexity, which seems ludicrous.

yiyus2• 9 years ago

I see it as an analogy with how, in maths, to fully understand a complicated concept you must be able to explain it using more and more basic definitions, but that does not mean you have to express everything in basis to fundamental axioms, just that you could.

Maybe explaining a complex concept in simple terms would take you 2 hours, 12 hours or 3 days, but you can do it if you really understand it.

marknadal• 9 years ago

Ah, I love Feynman. I see some other people in this thread arguing against even bothering to do this, which is sad.

We've started doing Explorable Explanations / Animated Explainers, here are some we've done and some that others have done:

- Explaining how GIT works: http://gun.js.org/explainers/school/class.html

- How neurons work: http://ncase.me/neurons/

- How end-to-end cryptography works: http://gun.js.org/explainers/data/security.html

- How gerrymandering works: http://polytrope.com/district/ (by a friend of mine!)

- How sorting on partial data / data streams works: http://gun.js.org/explainers/basketball/basketball.html

And more! It is possible, it can be done. But it is hard. That is no excuse for not trying though. Big shout out to Bret Victor's work for starting a lot of this, and thanks to Feynman for encouraging and practicing what he teaches.

flavio81• 9 years ago

In science and engineering, there are some things that can't just be explained in a small amount of simple words to laymen.

Sadly it's 2017 and the popularity of TEDTalks make the laymen think otherwise.

mabbo3• 9 years ago

Edit: apparently, I have been misinformed for a very long time. These are still excellent lectures to watch though!

The Feynman Lectures are now on Youtube[0], and I like to watch them (all of them) every few years. I highly recommend that if you've never seen them, you take some time and watch them- really watch them. Close the other windows, turn your phone to do not disturb, and really watch these masterpieces of education.

[0] https://www.youtube.com/watch?v=j3mhkYbznBk

shas32• 9 years ago

These lectures are different from his famous Lectures on Physics. The lectures you linked to were compiled in "Character of Physical Law" and are not related to his Caltech undergraduate courses where he presented his "Lectures on Physics" content.

You link to: https://en.wikipedia.org/wiki/The_Character_of_Physical_Law

"Feynman Lectures on Physics" are: https://en.wikipedia.org/wiki/The_Feynman_Lectures_on_Physic...

s_ngularity2• 9 years ago

Ah, you beat me to it

mabbo3• 9 years ago

....

Are you serious?!?!

Oh shit, that's... I've been grossly misformed for a very long time.

s_ngularity2• 9 years ago

To be more clear, the lecture series you are talking about is called "The Character of Physical Law" and is not the same content that one would get from reading "The Feynman Lectures on Physics", which is a rigorous course in most of undergraduate physics. But I highly recommend the "Character" series. Just wanted to avoid having people think they're the same thing.

mabbo3• 9 years ago

Yeah, I'm an idiot. Now I need to go find the actual lectures.

peterwwillis2• 9 years ago

I can simplify how a car engine works, but that doesn't mean I understand how the air to fuel ratio is obtained.

Opposite example: Simplify how walking works, and make sure to include the critical systems such as major muscle groups, stabilizers, vision, inner ear, thigh/knee/pelvis/hip construction, the curved spine and its connection to the head, and blood pressure flow/regulation.

sh8710• 9 years ago

Everything should be made as simple as possible, but no simpler -Albert Einstein.

zobzu2• 9 years ago

As often, AE's killing it. That's exactly right.

outworlder2• 9 years ago

Still, you understand how it works. Is it enough to build one? Of course not.

You'd be missing a lot of experimental data that has been collected for decades. You'd be missing the metallurgy, etc.

The basic principle is very simple. Maybe you could even build a low powered version, given materials and time.

If you insist that understand how to obtain the proper air to fuel ratio is required to understand how an internal combustion engine operates, then I'd say we don't really understand anything at all. Can you mine and refine the ore to create the allows it is made of? Can you program the ignition (or alternatively, build a carburator)?

We all need to stop at some point.

peterwwillis2• 9 years ago

The funny thing is, I actually can mine ore, smelt it into iron and forge it. That doesn't mean I can explain how that works (monoxides in a fuel binding to oxides in iron ore to separate iron from slag, aligning grain and changing durability by heat treating, etc). Maybe that doesn't matter if all you want to do is produce pig iron, but if your specific engine design requires a specific grade of alloy, now you need to fully understand metallurgy.

Take it a step further and the engine is built, but you need to make a modification (forced induction, race fuel, etc). If you don't want your engine to blow up, now you need to understand air/fuel mixture. Sure, I can do something with a simplified understanding. But the lack of a complete understanding will leave me with a blown-up engine.

Does it follow that if I understand metallurgy and internal combustion engines, but can't simplify it, that I don't understand it? Of course not; the entire premise was that I already understood it. Simplification does not show you understand something. It can only provide a shallow, incomplete understanding.

So you don't need to be able to simplify to understand. You need to understand to understand. You need to simplify to provide a simplistic, shallow view.

NumberSix• 9 years ago

This is Feynman from the introduction to his Feynman Lectures on Physics:

The question, of course, is how well this experiment has succeeded. My own point of view — which, however, does not seem to be shared by most of the people who worked with the students — is pessimistic. I don’t think I did very well by the students. When I look at the way the majority of the students handled the problems on the examinations, I think the system is a failure. Of course, my friends point out to me that there were one or two dozen students who — very surprisingly — understood almost everything in all of the lectures, and who were quite active in working with the material and worrying about the many points in an excited and interested way. These people have now, I believe, a first rate background in physics — and they are, after all, the ones I was trying to get at. But then, “The power of instruction is seldom of much efficacy except in those happy dispositions where it is almost superfluous. ” (Gibbon)

Richard P. Feynman, 1963

http://feynmanlectures.caltech.edu/I_91.html

Note that by his own account, most of his students did not do well. James Gleick's biography of Feynman, Genius, has a longer discussion of the disappointing results of his lectures to undergraduates at Caltech, many of whom reportedly stopped attending the lectures as they were not getting anything useful out of them.

That Feynman in fact had difficulty explaining freshman physics to the highly qualified students at Caltech surely does not indicate he did not understand freshman physics.

Some topics are simply very complex. It is not clear that they can always be conveyed in simple terms. In some cases, a "big picture" explanation may be possible but the details remain complicated. In some cases, a hand-waving analogy to some everyday phenomenon may create the illusion of understanding but be misleading or wrong.

To give a specific modern example, a state of the art video codec such as H.264 is extremely complex, built of many complicated components and sub-algorithms. While it may be possible to explain the big picture in relatively simple terms, the detailed implementation and operation is not simple. The inability of someone who creates or implements a video codec to explain it in simple terms to a layman is not an indication that they do not understand it.

JackFr• 9 years ago

The best math professor I ever had, was in a 400-level Real Analysis class. His particular skill was that he basically had mastered the catalog of incorrect mental models students developed.

He would be proving something in class, someone would stop to ask a question, and from their question he would know not to try to answer it as asked, but rather he knew they were asking the wrong question, because the question was predicated on a misunderstanding of something three or four steps back.

Now these were proofs that a working mathematician could probably do in their sleep, but they were a level up in terms of abstraction for most of the students and to be able to drag us along with him was a rare talent.

dtashima5• 9 years ago

I always felt that the Feynman Lectures were really, "an incredibly deep understanding of freshman level physics, targeted towards physics graduate students." (As opposed to freshman level physics targeted towards pre-med students.)

Even after I got my undergrad degree in physics I would reread the Lectures and would see things on a whole new level than I ever understood them the first time.

Edit: even "Surely you're Joking" had jokes that only someone that had graduate level general relativity would get (talking about "gee-mue-nue, gee-mue-nue")

Radim• 9 years ago

Another example, even more bare-bones, is AI.

We now have programs that "understand" certain domains better than humans. And yet there are no "simple terms" to explain their understanding, reduce it to a neat closed-form formula.

Isn't it a mistake to assume a nice, elegant explanation, a cute human "narrative", must always exist?

"But Radim, the computers don't really understand the domain!". Sorry, a cop out, No True Scotsman fallacy. In what way do they not?

This is crystal clear with Go: the little stories humans have built to deepen their understanding of the game over 2,000 years are irrelevant to a game's outcome. The details and variations are all that matters, and there is no way to reach the computer's level of understanding of the game without understanding the details.

nroach• 9 years ago

I like the sentiment behind this article, but simplification (like lossy compression) omits information for the cause of simplicity, leading to an incomplete understanding.

Take for example legal concepts like securities law or environmental regulation. Yes, you can "simplify" an explanation of the Securities Act or the Paris Accord enough to fit them into a tweet, but you lose information necessary to formulating a full understanding.

If you're trying to have an informed debate about policy adoption, the details matter.

pwaivers• 9 years ago

Being able to explain something in simple terms is actually REALLY difficult to do. It is a skill in itself. Someone can intuitively understand math very well, but lack the skill to explain it to someone else at all.

specialist3• 9 years ago

I love organizing, simplifying things. Geeks are addicted to complexity. I think it's some kinda machismo thing.

This incompatability has caused me problems my entire career. I've more or less stopped trying. I just do what I'm told and save my creative energy for my personal projects.

nebulous1• 9 years ago

I think some people (even lots of people) are pretty bad at explaining things, even things they understand.

wolco• 9 years ago

If you can explain something in simple terms you may not understand the complex details.

If you hold a complex idea in your head translating that into English can be difficult because part of the process is removing/altering information to fit into existing notions. That is why buzzwords are popular they can take an idea and put it in a relatable concepts for the masses.

jknoepfler2• 9 years ago

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-something who thought they could learn any subject in a few hours, cushioned thoroughly by the illusion of understanding.

"Oh yeah, I understand the mechanisms of human vision. It's just rods and cones."

"I understand the causes of the American revolution. It was just people protecting their property."

"I understand Joyce's Ulysses. It's just follows three people from Dublin over a single day. I read the Cliffs notes."

"I understand why coffee makes me alert. It's just blocking some brain things that make you sleepy."

Now, I will agree that if you don't know how to break interactions down into teachable parts, you will probably have trouble as an engineer or scientist both advancing your own knowledge and introducing people to the field. But to suggest that your understanding of a subject hinges on being able to deliver an explanation in simple terms is just silly.

api2• 9 years ago

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.

rrdharan• 9 years ago

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.

sh8710• 9 years ago

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.

wellpast• 9 years ago

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).

sh8710• 9 years ago

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.

jshelly2• 9 years ago

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

JumpCrisscross• 9 years ago

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.

jknoepfler2• 9 years ago

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.

justbaker• 9 years ago

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

I do agree it is arrogance.

itsdevlin• 9 years ago

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.

0xdeadbeefbabe• 9 years ago

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

erickhill• 9 years ago

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.

jfoutz• 9 years ago

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

keithnz2• 9 years ago

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.

specialist3• 9 years ago

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.

meanperson2017• 9 years ago

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

orthoganol• 9 years ago

? 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.

jansho• 9 years ago

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

jokoon2• 9 years ago

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.

SomeStupidPoint2• 9 years ago

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.

ac0kg• 9 years ago

"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.

tnzn• 9 years ago

That's why there's peer review.

mtdewcmu• 9 years ago

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.

Retra2• 9 years ago

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.

clay_to_n• 9 years ago

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.

dec0dedab0de• 9 years ago

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.

frahs• 9 years ago

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...

ReidZB• 9 years ago

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...

munificent• 9 years ago

    > 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.)

rdlecler1• 9 years ago

Nassim Taleb makes a convincing argument that you first understand something implicitly and then later it becomes formalized. I'm not sure I buy into the idea that people with great communication skills have privileged understanding. The underlying assumption here is that understanding is verbal. I reject that hypothesis.

naikrovek• 9 years ago

This is so untrue. If true, beings that can't speak or write can never understand anything.

I understood very early in life that if I cried I would be hit. I couldn't talk, write, or communicate my understanding in any way, but I understood clearly.

dredmorbius3• 9 years ago

Such beings have no social knowledge.

taurath• 9 years ago

My favorite corollary (attribution unknown) -

"But if you can ONLY explain something in simple terms, you still don't understand it"

Animats2• 9 years ago

That works for physics, which seems to be parsimonious with its base concepts. The equations which define most of physics fit on one sheet of paper.

It doesn't work for biology, which is complicated at the bottom. Evolution doesn't have the parsimony of physics. Nor does it have to be understandable by humans.

Whether it works for software is a design issue. It's certainly possible to create software which cannot be explained simply.

dredmorbius3• 9 years ago

The essence of biology: https://www.reddit.com/r/dredmorbius/comments/6fupwz/the_ess...

(I'm actually really hoping for someone to show up and say, "Um, gosh, I don't know how to say this, but that's just so wrong..." And then how.)

cestith2• 9 years ago

"There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." - C.A.R. Hoare

aeturnum• 9 years ago

I think this is broadly true, but not in the way a lot of other commentators mean.

Explaining something in simple terms does not mean you _fully_ explain it. You explain the essence (or what you see as the essence) of the thing. Google search is: you type a question into a box and Google shows you the best answer. Google search is a lot more than that, of course, but if you can't "boil it down" you don't understand it.

This is the top line of a git commit v.s. the comments you leave in the source code. You can spend months working on thousands of lines of code, bur if you can't describe it in a single sentence (while leaving a lot out!) it's a bad sign.

makecheck• 9 years ago

It's not realistic to expect this. If everything could be simplified to this degree, you would never need experts.

It is also dangerous to assume this, because that is exactly how we reached the "my uninformed opinion is as valid as your years of experience" aspect of the current political climate. NO, things are NOT as simple as you think they are just because you saw it in the space of a tweet!

On the other hand, it is important to recognize expertise over bullshit. The easiest defense is having several experts, since at a certain point they would need to do an awful lot of collusion to just make things up between them (i.e. if enough of them agree then what they say is apparently correct).

mjevans• 9 years ago

The best we can say is that if there is a strong consensus among experts that it is, to the best of our current knowledge, correct.

It's at least more correct than someone with zero training in that field. Dissenting opinions among experts should also be considered, by such experts, and the points at which they disagree with the logic or knowledge carefully examined by all.

pimmen3• 9 years ago

Nobody's saying that "explaining" is the same as "teaching". Nobody's saying that "basic understanding" is the same as "mastery".

This is just to get people started, it's not a substitute for years of hard work and study. Feynman never claimed this and I think this is missing the point entirely. Unless you have a complete model of how the system works you can't come up with suitable analogies to gently ease in new people to get started.

SiVal• 9 years ago

Understanding something is having a good working model stored the way brains store models, which is quite a complex network. Explaining it requires finding a way to serialize it that makes it as easy as possible for a listener to reconstruct the model in his own mind.

I think the effort involved in trying to come up with a serialization causes us to more carefully examine our models, which usually improves them.

But I don't think the lack of a good serialization implies the lack of a good model.

tshadley• 9 years ago

You serialized that very well.

tutufan• 9 years ago

Linear time suffix tree construction. You have 90 seconds. Go!

:-P

chrisallick2• 9 years ago

This is what I'm saying. There is complex and there is complicated.

vlasev• 9 years ago

Here [1] is not 1, but 3 different levels of complexity. Not 90 seconds though :)

[1] https://stackoverflow.com/questions/9452701/ukkonens-suffix-...

chrisallick2• 9 years ago

Someone explain cryptocurrency!

dredmorbius3• 9 years ago

https://davidgerard.co.uk/blockchain/

std_throwaway• 9 years ago

Keep it as simple as possible but don't try to make it more simple than it actually is.

throw2016• 9 years ago

This is eternal. The expert paves the way to understanding. Its only because of their expertise that they can simplify and explain it in a way that others can understand. They have a firm grasp of the concept. Understanding is not equal to expertise, just the first step.

I think there are too many times when people affect a tone of authority and expertise and hide their lack of understanding in verbiage and complexity while making excuses for their inability to explain it to the layman.

keithnz2• 9 years ago

I think you can't explain something in simple terms if you don't understand it, is true, but the other way around isn't entirely true, or at least it's a bit more fuzzy.

Often, it takes a lot of awareness of what are the common mental models / mental blocks other people have when learning the concept you are trying to communicate. You have to structure things as a series of strategic progressions before tackling the most complicated form of something, all of that is more the art of teaching ( which of course requires good understanding )

Of course, if someone can do that, it's a brilliant proof they do understand something.

If they can't do it, then it can leave you with doubt what someone else understands. Which in Apples case may be considered entirely unacceptable.

cryptozeus• 9 years ago

"What I cannot create, I do not understand"

littlestymaar• 9 years ago

IMHO, this statement never hold for Maths : since all math reasoning is just the construction of a logical and symbolic proof based on a set of existing theorems and the underlying axioms, it requires the student to :

1. be familiar to the logical reasoning : what «implies» or even «for any x» means. 2. know the relevant set of theorem and axioms used in the demonstration.

You could probably illustrate what a mathematical result implies in some real-life example, but you won't be «explaining» it.

Quantum physics is a really good example of this, because it's not that difficult to understand if you look at it with the mathematical PoV : it's basically linear algebra in infinite dimension, you have vectors (in the space of «functions of |R³») and linear applications on these vectors (with all properties of such applications, like eigenvalues and eigenvectors), etc. But if you try to «explain» it in simple terms, you're going to distort the reality to fit in the macroscopic-scaled human representation of the world and you'll probably say things that won't be true.

moarrgan• 9 years ago

I feel like a lot of the commenters here are making a false assumption, arguing "just because you can explain something in simple terms doesn't mean you understand it - look how much nuance and complexity gets lost!" That statement makes the assumption that you must explain the subject to another individual to the point where they understand that subject as well as you do. Well, obviously you are going to lose complexity, just on the basis of explaining something in simple terms. The point is that if you cannot distill something to its core ideas to the point where someone else will gain a basic understanding of that concept, then you do not understand what its core ideas are, and therefore do not understand the concept itself. No one is arguing that what took you 10 years and a PhD to understand is something you can explain "simply" to someone and they will emerge with the same level of understanding as you have. No, they will emerge with a basic understanding of that concept if you have explained it well.

juandazapata• 9 years ago

What is a monad?

Retra2• 9 years ago

It's a pattern of taking a series nested items and treating them as sequential by implicitly passing the nesting context from one item to the next.

At least, that's the programmer's interpretation. Mathematically, they are algebraic structures that can behave analogously to this in a number of fashions.

barce• 9 years ago

Another way of putting this is: If you can't use lego blocks to build something, then you don't understand it. But why would anyone want to recreate Shakespeare using lego blocks, or recreate a motorcycle using lego blocks? I'm sure a 5 year old would love it to pieces. I would rather make a reproduction of a motorcycle with real metal.

zobzu2• 9 years ago

"or you just don't have good communication skills" It's a classic fallacy. While it has some truth to it it's not the only single reason to decide if you understand the subject or not.

In fact, "if you make this fallacy, you're a terrible human being" (which is sarcasm here since this very statement includes the exact same fallacy)

CatMtKing• 9 years ago

I practice taijiquan, a martial art. My teacher often describes concepts that I can relate to basic mechanics. When I do, it feels like I understand, but as my teacher says -- until you can actually express it with your body, you don't really understand.

For example, a lever seems conceptually simple, but to create a lever in the body is extraordinarily hard. The joints have to be solidly connected and free to open or close. The direction must be precise and rotation must not wobble. There are so many things that can err and lots of places for force to leak out.

leepowers• 9 years ago

Feynman is an outlier, a very rare talent that could handle very complex maths and also communicate these concepts in an approachable, charming, and laid-back style. This is an in-born talent and also a skill that can be taught. But communicating complex systems is a separate proficiency from understanding those systems.

The main issue when explaining concepts (especially maths concepts) is switching from one formal context to another, deciding what details to omit, and determining what rules in both contexts should be treated as analogous.

Think of a translator. He/she/it needs proficiency in two languages to do a proper translation. Lacking a second language precludes translation. But it doesn't affect mastery of your native tongue.

ChuckMcM2• 9 years ago

"What I cannot create, I do not understand."

This actually came up for me at the office. I was asking a bunch of questions about the Z transform and the Fast Fourier Transform. The person I was talking to said, "Hey, just call the function in MATLAB, it doesn't matter how it works, just that you understand what it is saying."

All of my life I have rebelled at this notion. My earliest recollection of running into it was when I was in grade school and took apart three wind up alarm clocks, each more carefully than the one previously. My Mom was curious what I was looking for and I told her, "How does a clock know how long one second is?" She didn't know, and I didn't know, and while I had mastered using a clock and accepting that it would go off when I set it to go off, I didn't really "know" how a clock worked until I had taken apart and identified, (and modified to validate the identification :), the escapement.

jgamman2• 9 years ago

surely there's some tension between these two extremes. for someone learning how to _use_ FFT's, treating them as a black box for a while is useful so they can build some intuition etc and then, if it floats their boat, go back and dive deeper. as a chemist, I didn't give a rat's how the thing worked, I had spectra to analyse...

Conversely, if you had to deep dive everything, you would not get _anything_ done since there's always a deeper level.

Maybe it's just an experience thing where you start to appreciate that for most things (probably all bar one or two) you are just the privileged user of other people's expertise.

ChuckMcM2• 9 years ago

I don't think I was clear in my comment, I personally find great joy in learning things (which makes me something of an autodidact) its just one of those things.

My desire to understand things though has never been a hindrance to using them. Long before I understood how compilers worked I was using them daily, long before I understood how PN junctions did what they did I was soldering diodes into boards.

It only generates tension when I want some tool to do something that it cannot do, and reasoning about whether the constraint is due to the tool or the implementation of the tool can only happen if I really understand what the tool is actually doing.

draw_down• 9 years ago

I think I've about gotten my fill of this piece of, uh, wisdom. It strikes me as one of those things that sounds good but is less relevant than we'd like to think.

jpmattia• 9 years ago

If curious: This Feynman quote was more specifically about the spin-statistics theorem.

https://en.wikipedia.org/wiki/Spin%E2%80%93statistics_theore...

And to be fair, it's pretty rough sledding even when you understand the operators involved.

williamle8300• 9 years ago

Person A: Trump is colluding with Russia...

Person B: How?

Person A: You're a dummy! There's mountains of evidence!

Person B: Like...

Person A: You're killing the vibe brah.

jjguy• 9 years ago

Einstein said it first:

If you can't explain it to a six year old, you don't understand it yourself.

https://www.goodreads.com/quotes/19421-if-you-can-t-explain-...

elnygren• 9 years ago

"had I more time, I would've written a shorter letter".

Remember that "in simple terms" does not mean easy or over simplifying something. To me it means making a to-the-point and jargon-free explanation.

CalChris• 9 years ago

I interviewed a woman once who'd graduated from Caltech. She was massively overqualified and a fine fit. So about 10 minutes into the interview I started just having a nice conversation.

She'd gone to Caltech. That was on her resume. So I asked her if she'd ever taken a class from Feynmann. That was actually unlikely but she had sat in on a seminar with Feynmann once. She said he could explain the most difficult material and that you would understand it. You would understand it walking away and this would last about 15 minutes during which time you confuse yourself.

lngnmn• 9 years ago

This is how to distinguish a cosplay of intelligence from true intelligence, among other things.

The Buddha and the Upanishadic seers were exceptionally good with explaining complex phenomena in simple terms.

Apparent sophistication is a sign of a confusion. Clarity is an evidence [of deep understanding].

Nature is vastly complex but not complicated (a few fundamental laws at work). Only simple things work.

olegkikin• 9 years ago

That's just not true, it's confusing explanation and oversimplification. Many complex things require years of study just to understand that thing even in the most simple terms. Try and explain string theory to someone who has no idea of particle physics, colliders, quantum theory. At best you can make up some abstraction which doesn't explain anything.

matthberg• 9 years ago

I think this is part of the beauty of simple.wikipedia.org. It is not only a way for laymen to understand complicated things, yet proof of the research being an actual understanding of the concept.

In the words of the xkcd on the subject, (check the title text):

"Actually, I think if all higher math professors had to write for the Simple English Wikipedia for a year, we'd be in much better shape academically." https://xkcd.com/547/

Tomminn• 9 years ago

Corollary: All ideas worth understanding are simple.

timoth3y• 9 years ago

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.

known• 9 years ago

“If you can't explain it to a six year old, you don't understand it yourself” ―Albert Einstein

Scea91• 9 years ago

Why is this quote used so often even when it is so ridiculously false? Actually, did Einstein ever say that or is it just one of the fake quotes that are attributed to him?

imjustsaying• 9 years ago

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.

DrJokepu• 9 years ago

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.

jancsika• 9 years ago

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

killjoywashere• 9 years ago

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.

mncharity• 9 years ago

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

And an underappreciated corollary is...

If you want something explained well in simple terms, you have to find someone who understands it deeply.

In the sciences, that means someone who has it as their research focus. Because as you move away from that focus, understanding rapidly becomes ramshackle. Leave someone's subfield, and you might as well be talking with a random graduate student (in that field). And that's hopeless.

Thus many research talks have videos and stories which would nice to have in a K-12 classroom. And most all K-12 education content is incoherent wretchedness.

An old essay of mine: "Scientific expertise is not broadly distributed - an underappreciated obstacle to creating better content" http://www.clarifyscience.info/part/MHjx6 In which a 5-year old with finger paints wants to paint the Sun, but encounters astronomy graduate students.

"I am sorry for the length of my letter, but I had not the time to write a short one." - Blaise Pascal 1657

There's a sad little genre of low-quality science education research that goes: "I tried to teach topic T to students of age A. I taught it <really really badly>. Surprisingly, that didn't work! I've reach the obvious conclusion: students of age A are developmentally unready to learn topic T."

But understanding, while necessary, is not sufficient. At PhD poster session practice, it's often remarkably hard to help candidates develop an "elevator pitch". To clearly understand the core of what they've spent the last n years working on. I'm still amazed by how often one gets something like "wow, now I can explain it to my parents".

cryptica• 9 years ago

The term "simple terms" is subjective and depends on who the audience is.

A popular question to qualify for engineering job interviews is "describe in simple terms what happens when a user accesses a website on the Internet" - The question doesn't give any info on who the target audience is so you never know what level of detail you're supposed to go into. Because this is an engineering question, I tend to go into more detail but after a certain level, you can't really keep it simple because the reader has to understand what things like cache are... Else you will spend 20 pages just writing definitions.

stretchwithme• 9 years ago

People know a lot of things they don't necessarily know how to explain. A lot of people don't know how to teach.

blackkettle• 9 years ago

If you don't understand something and/or cannot explain or describe it, should you believe it? I think this is a very difficult question.

Ngunyan• 9 years ago

Really? In simple terms, explain how this works concisely.

NicoJuicy• 9 years ago

Simple trick, you don't have to explain everything and use similar things ( when possible) in layman context. Explaining only cause and affect without the method used can greatly simplify things when talking to non-programmers / non-technical people

Eg. IP = A address like your home address. So the internet knows where to search. We use zipcodes, the web uses numbers.

Then: I need to adjust a dns-record with our IP. Becomes, I will point the website to our address.

If it's not obvious, then all my previous clients are lying ( just mentioning it, cause it's possible)

hiq• 9 years ago

A related maxim by Nicolas Boileau (1636 - 1711):

Whatever is well conceived is clearly said, And the words to say it flow with ease.

Ce que l'on conçoit bien s'énonce clairement, Et les mots pour le dire arrivent aisément.

onikolas• 9 years ago

Explaining something is compressing information and then transmitting it. As we know, there are limits to how much we can losslessly compress information.

So, no, you cannot explain everything in simple terms. But you can find sweet spots when trading brevity for accuracy.

danmaz74• 9 years ago

Ok, so nobody understands quantum physics...

bo1024• 9 years ago

I'm in academia and get to listen to and interact with extremely smart people who are experts in their subject. This quote really hits home for me.

I'm not saying I'll take it as literally true in every situation. But what I love about the quote is that it sets the bar for "understanding" very high.

People sell themselves short on understanding - they reach a certain level and are satisfied that they understand something, when there is actually much deeper understanding to be had. For example, being able to write a proof of a theorem can be very far from understanding why it's true, but even mathematicians sometimes pretend it's the same.

So I like that this quote challenges us to understand things more deeply. And more often than not, I find it rings true.

(A basic example coming to mind is the determinant of a matrix. Can be explained in simple terms to children (at least the key idea), or in confusing terms to freshman linear algebra students....)

twelvedogs• 9 years ago

lol, apparently i don't understand anything

combatentropy• 9 years ago

I think this statement is a tautology. To understand something is to know it in simple terms. To understand something is to have mentally broken down a complex subject into its simpler pieces. For example, to understand a car engine is to take it apart in your head and know each part, how it moves, and what it does.

Many think they understand something, when really they only know how to use it. For example, I understand how to use a computer, but that doesn't mean I understand how a processor works at the level of registers and assembly language. So if I were to try to teach someone a computer, then I could say things like "Click that, and this will happen," or "Type such and such, and then this other thing you want will happen." But if anyone asked me about how that actually works, to follow all the way how a physical mouse-click gets transformed into a change in the window on the screen, then I couldn't. Or, even if I could, it might take me half an hour to explain it, depending on how much they want to know.

So maybe it's that we undestand things, but at different levels. Few people understand something at its deepest level. In fact, physicists would say no one does.

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

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