If you can’t explain something in simple terms, you don’t understand it • Hacker News Board

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

#111

Post by keithnz » Thu, Jun 15, 2017, 10:24 PM UTC

jfoutz wrote: post #104

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…

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 thin…

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.

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

#112

Post by peterwwillis » Thu, Jun 15, 2017, 10:25 PM UTC

outworlder wrote: post #66

peterwwillis wrote: post #34

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.

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 inter…

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.

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

#113

Post by orthoganol » Thu, Jun 15, 2017, 10:27 PM UTC

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…

? 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.

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

#114

Post by yiyus » Thu, Jun 15, 2017, 10:27 PM UTC

mikebenfield wrote: post #27

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 i…

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.

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

#115

Post by jshelly » Thu, Jun 15, 2017, 10:30 PM UTC

sh87 wrote: post #86

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…

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 sys…

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

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

#116

Post by cryptozeus » Thu, Jun 15, 2017, 10:30 PM UTC

"What I cannot create, I do not understand"

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

#117

Post by littlestymaar » Thu, Jun 15, 2017, 10:30 PM UTC

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.

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

#118

Post by JumpCrisscross » Thu, Jun 15, 2017, 10:30 PM UTC

sh87 wrote: post #86

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…

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 sys…

> 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.

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

#119

Post by dredmorbius » Thu, Jun 15, 2017, 10:30 PM UTC

Animats wrote: post #75

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…

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.)

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

#120

Post by jknoepfler » Thu, Jun 15, 2017, 10:31 PM UTC

sh87 wrote: post #86

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…

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 sys…

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.