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The general concept is known as https://en.wikipedia.org/wiki/Lie-to-children and I think you'd be hard pressed to teach/learn/apply anything of significance without this "well actually it's more complicated than that" approach and recognizing how far you need to go with it to aptly do some task.



There's no need to lie to children. Telling children "multiplication is a separate operation on numbers, but it works like repeated addition for the counting numbers you're familiar with" is not a lie.


The continuing series of qualifications "it's kinda like this, for what you're talking about" gets pretty rough there, even when explaining, say, Kubernetes to adults! It can be a confidence crusher.

There's also the flip side response which is always asking a lot of questions about "well then what are the other sorts of numbers" and eventually getting shut down "we're not talking about that now" which comes back to the "who decides what you're smart enough to hear about now" question in its own way. Or "oh the teacher doesn't actually know what the difference is, or why this isn't 'true' 100%."

Despite the cutesy name, I don't think omission of detail is the same as lying. It's often impossible to tell 100% the truth. You probably don't even know it yourself!


> It can be a confidence crusher.

If confidence gets priority over truth in explanations, then society will churn out people who are confidently wrong. This is a bad idea even if everybody does that and even if it is the traditional approach.

If people were honest that they don't know something then the world at large would be a lot nicer to live in.


I think this is backwards. The public at large are pretty honest that they don't know math. The world would be a much better place if they were able to do practical algebra, even if the higher truths of abstract mathematics never enter their minds.

I really don't see people being confidently wrong about abstract mathematics as an issue. I certainly don't know the rigorous definitions of an integral, but I can apply the concepts of calculus to everyday life perfectly fine. People who care about rigorous math can do rigorous math, and I'm glad if they teach me an intuitive understanding that lets me live a happy, productive life.

Personally, I find layers of abstraction necessary for learning. Maybe there are people who don't, I suspect they would have to be prodigies though. Tell me how to add fractions practically, then teach me the principles when I need to know them. Framing that as a lie seems wrong to me, I'd call it "bounded knowledge".


The confidence is in the ability to learn a topic, not confidence about the knowledge.


It seems to me that the way to build people's confidence in their ability to learn is to allow them to learn. That means not making oversimplified statements because you don't think they're "ready" for more details. It means giving them the details, and letting them decide when they've had enough for now. (Of course one's time, say in a classroom, will be limited, so at some point one has to say "we don't have time to go into this further in class now"--but that's still letting them know that there are more details, and they can dig into them further on their own.)


That doesn’t work for lots of people (including myself). If you’re spending a lot of time on details that don’t actually matter for the topic at hand, it takes away mental bandwidth that should be spent on the topic being covered.


Refusing to answer curious students questions isn't helpful. Giving them a hint and telling them you'll get back to it works fine. They're smart enough to understand they aren't having to wait because they're incapable of understanding, but because other things need teaching first. I know I did. The good teachers were encouraging of the curiosity while back-burnering something, others responded less patiently with things like "we're not there yet!", which made them seem like bad teachers to me, even back to elementary.


> The continuing series of qualifications "it's kinda like this, for what you're talking about" gets pretty rough there

The qualifications are there; that's just a fact. Being told about them, or at least about their existence if not every detail of them, up front seems better to me than finding out about them later on when your mental model is solidified around the simplified version that you then find out doesn't always work.

> I don't think omission of detail is the same as lying.

Saying "multiplication is repeated addition", without qualification and without any caveats, is not "omission of detail". It's a false, categorical statement, i.e., lying.

As for where the line is where you stop giving details, obviously that will depend on the circumstances. A teacher who says "we don't have time to talk about that during class today, but yes, there is much more detail here that you can look into on your own" is not lying and is not saying the child is "not smart enough" to take in all the detail now. (Bonus points if the teacher says "see me after class and I'll give you some pointers on where to go for more information".) A parent who says something similar because they have to get dinner ready and the child needs to do the rest of their homework before bed is also not lying and not saying the child is "not smart enough". Limitations of time are a fact of life, and children need to deal with it just like the rest of us.

A teacher who just says "we're not talking about that", or who doesn't even know about the qualifications, or who gets snippy when a child asks a natural question, is obviously not doing the child any good; but that is because of the teacher fixating on a simplified model and treating it as "the Truth", so doing more of that won't fix it.


If you don't lie to children you confuse and discourage them. I know because my own internal desire for precision often is to the detriment of my pedagogy.


Let's not take the word "lie" out of its context and then get hung up on it. We're not actually lying to children by simplifying the explanation down to what they can comprehend with the tools they have at that stage.


> Let's not take the word "lie" out of its context

I'm not the one that used that word. If people are going to reference a concept that's been published in a book and uses that word, they should own it and be prepared to justify it. If they can't do that, they should not use the word in the first place.

To be clear, I'm not saying you are one of those people. But the poster I was responding to is.


I'm not saying you shouldn't use the word. I'm saying you shouldn't ignore its very specific and specialized context. Taking things out of their context often leads to problems, just like in this case.


But you can define multiplication based on abstracting repeated addition. That how we did it my analysis class, although I forget some of the details. So if you say multiplication is repeated addition, it really isn't a lie.


But did your analysis class define addition on the naturals? Then that's an operator for the naturals. And then for integers, rationals, etc.


Yep and how to construct, the naturals from set theory, the integers from the naturals, the rationals from the integers and the reals from the rational. I've forgotten the details at this point, but I remember the conclusions.


They don't need this information when learning that 3 groups of 5 fruit are 15 fruits. It's not in the natural order of understanding principles.


> They don't need this information when learning that 3 groups of 5 fruit are 15 fruits.

They also don't need the "information" that multiplication is repeated addition, period, full stop. But that's what others in this discussion appear to be trying to argue for.


I'm really not sure how you could arrive at an understanding of multiplication without first going through the exercise of adding up X groups of Y to yield X * Y. We don't need to declare to children that the precise definition of multiplication is repeated addition. If that's what you're arguing, we agree. If it's that 3*5 shouldn't be explained as 5+5+5, I'm not sure how kids would be expected to learn the subject. We can't transactionally insert comprehensive math knowledge, so it's got to be incomplete along the way.


> I'm really not sure how you could arrive at an understanding of multiplication without first going through the exercise of adding up X groups of Y to yield X Y.*

Arriving at an understanding of one particular special case of multiplication might indeed be a necessary step towards arriving at an understanding of multiplication in general, but that doesn't mean the two are the same.


Well, that would be true if all children were as smart and analytically adept as you.


It looks like splitting hairs, but I also think it makes a difference to state upfront that it’s an oversimplification.

Kids actually understand the point, and they can decide if they care enough to ask more questions or if it’s good enough for them.

We faced that when teaching divisions. Saying upfront we’d explain falsehoods for the sake of simplicity helped set aside the more difficult questions (infinity, etc.) that came right after. We just say it’s the complicated parts and move on.

The best aspect is they are more receptive to have their mental model broken afterwards, instead of clinging to what you explained as fully true.


I think this viewpoint is pernicious. A child doesn't have to be "smart" in order to deserve being told the truth.

Or I could turn your remark around: what makes you, the adult, think you are so much smarter than the child that you can correctly judge what lies are OK to tell them? Are all adults really that smart? (Are any of us?)


An abstraction/simplification/shorthand is not a lie. People don't say "multiplication is repeated addition" because they are trying to hide the truth for some selfish reason. It's a pedagogical strategy to help people learn a new abstraction by analogy to an old one. These kind of crutches are a necessity, you can't introduce all the complexity of the world to someone all at once. This applies to every subject - science, history, writing. Simple notions and shorthands are introduced first, and complexity and nuance added on later.

Is it a "lie" to teach kids just learning chess that queens are worth more than any other piece and you should always protect your queen, even though there are advanced situations when it makes sense to sacrifice your queen for no immediate material gain?

In this specific case, introducing the ideas of "operations" and "counting numbers" into the picture muddies the waters, most kids who are just learning multiplication won't have any idea what you mean by those concepts.


> An abstraction/simplification/shorthand is not a lie.

"Multiplication is repeated addition" is not "an abstraction/simplification/shorthand". Doing that for multiplication would be saying something like "multiplication is a distinct primitive operation, but it works like repeated addition for whole numbers, so that's what we'll be learning how to do now." Is that really so hard?

> Is it a "lie" to teach kids just learning chess that queens are worth more than any other piece and you should always protect your queen, even though there are advanced situations when it makes sense to sacrifice your queen for no immediate material gain?

If you tell them everything you just said, no, you're not lying. But if you just tell them "always protect your queen", without explaining anything about why and without saying that there are some advanced situations where you might break this rule, yes, you're lying. It only takes a couple of sentences to add that extra information. Again, is that really so hard?

> In this specific case, introducing the ideas of "operations" and "counting numbers" into the picture muddies the waters, most kids who are just learning multiplication won't have any idea what you mean by those concepts.

Um, what? We're assuming they already know about addition of whole numbers. So it is simple to tell them "this addition thing that you learned, that's an example of an operation", and "those whole number thingies that you learned how to add, those are numbers". Once more, is that really so hard?


> but it works like repeated addition for whole numbers, so that's what we'll be learning how to do now

I think it's an arbitrary perspective, whether you treat the whole number case as primary or the generalization as primary.

People may prefer to consider the extended definition more "real", but I think the argument for going the other way is that usually the original limited form of something is more likely agreed upon by most people, whereas the generalization can be done in multiple ways which may owe something to history and culture, or context.

I feel like math is fundamentally different than physics, where the more advanced theory is objectively closer to correct. With math, it's more of an arbitrary aesthetic or social judgment. Nothing ever stops you from generalizing anything even more than anyone did yet, right?


> I think it's an arbitrary perspective, whether you treat the whole number case as primary or the generalization as primary.

Axiomatically, I think it can go either way. But one still has to recognize, as you do, that there are more cases than just the whole number case, and that what works for the whole number case might not work for other cases.

> the generalization can be done in multiple ways

There are certainly cases of this, but I don't think the case under discussion is one of them. There is only one generalization of the whole numbers under discussion here, the one from whole numbers to rationals to reals (and on to complex numbers if you want to take it that far, and still further on to matrices for some people in this discussion). There aren't multiple ways to do that: the rationals, reals, and complex numbers are all unique sets.


Along with what allturtles said, I don't think it's right to call it a lie, which, to me, implies moving someone's model away from the truth (on the basis of them trusting you to convey the correct one). An oversimplified, "wrong" model doesn't do that; it moves them from ignorance toward the correct model (i.e. increases their prediction accuracy).

And yes, even when I'm in the learner's shoes, I prefer that a teacher start with an approximate model, and then refine it as they go further. Starting with the full thing is barely comprehensible.


> I don't think it's right to call it a lie

It's not a lie to tell them "this is a simplified model that doesn't include everything, but you'll be able to add more complexities to it later". But that's not what "multiplication is repeated addition" says. You would say something like: "repeated addition is a simplified model of multiplication that works for whole numbers, but doesn't work well in more complicated cases that you'll learn about later".


Yeah, and that's still too much inferential distance to feed to an elementary schooler.


You appear to have a much more impoverished view of kids and their ability to learn than I do. My experience (not to mention my memory of how I was myself as a kid) is that kids grasp the fact that there can be more to a subject than adults are able to teach them at a particular time and place, so they're ok with adults honestly admitting that. But they do not like adults telling them categorical statements that later turn out to be wrong.


You’re view of children seems to be more based on your memory of high school. That’s a lot different than your behavior as a 6 year old when these simple primitives are being taught.

Little kids don’t care about nuance when they’re still having difficulties with carries in addition. Your ideal world where we first explain children that base10 isn’t the only way to represent numbers and whatever other caveats simply doesn’t exist.

They don’t have the knowledge required yet to even understand the scenarios when “exceptions to the rule” apply.


There's a difference between prefacing a course with "oh hey these are simplifications that you'll improve upon in higher grades" vs loading down literally every claim with that long chain of caveats.


> loading down literally every claim with that long chain of caveats.

I have never proposed doing the latter, so you are attacking a straw man. Once it's understood that you're teaching a simplified, approximate model, you don't have to repeat in every sentence that you're teaching a simplified, approximate model. You just have to not say it's "the Truth", without approximation and without qualification.


I'm relying on these examples you gave of how to do it:

>"multiplication is a separate operation on numbers, but it works like repeated addition for the counting numbers you're familiar with"

>"repeated addition is a simplified model of multiplication that works for whole numbers, but doesn't work well in more complicated cases that you'll learn about later"

If you disagree that that's "long" or would feel that way in having to do it in every sentence, we can have a great discussion about that, but it is not a strawman -- you seem to reject the idea of giving the one caveat at the beginning of the course, and instead want to make each sentence rigorous.

If you recognize that your complicated sentences are probably not ideal for teaching math to second graders, then I think we're in agreement.


> If you disagree that that's "long"

I do. Some of the words might be changed, depending on what words have been used to describe the operation of addition and the set of counting numbers. But, as I think I've pointed out elsewhere in this thread, the very fact that the children know about addition and the counting numbers means they know what an operation is ("a thingie like addition") and what a set of numbers is ("a thingie like the counting numbers").

> you seem to reject the idea of giving the one caveat at the beginning of the course

I don't know where you're getting that from. I have already said the contrary--once you've said it, you don't need to repeat in every sentence.


How would you teach physics without lying to children?


Um, by not lying to them?

Do you have a specific example of where you think you need to lie to teach physics?


> Do you have a specific example of where you think you need to lie to teach physics?

If we are defining "lie" to mean "simplifying the model to allow students to understand what's going on" (which is what we're talking about) then basically every field of physics required some simplifications in order to teach.

For instance, it would be "lying" to teach Newtonian dynamics and Newton's theory of gravity at all without explaining relativity -- Newton's theory of gravity is "wrong" after all. It would be "lying" to teach electromagnetism without first explaining quantum mechanics. However it would be impossible to teach anything to a high-school or undergraduate student if you first had to explain everything else in order to teach F=ma or Gauss's law.

I think there's also a limit to how many times you can say "this is simplified" to students before they feel like they're being pandered to or that they're being told they're "not smart enough to understand the full theory". Physics was developed over many thousands of years, it's not really reasonable to expect a student to be able to learn it in one shot. Physics courses are often structured so that you learn concepts in historical order so that you learn how concepts were developed and what motivated future discoveries -- that is also a very useful thing to learn in addition to the actual physics.

I believe the same applies to mathematics education.

Source: I majored in physics. Every year we had an electromagnetism course and we learned that the model we had learned last year was too simplified to work with. Same goes for thermodynamics.


> If we are defining "lie" to mean "simplifying the model to allow students to understand what's going on" (which is what we're talking about)

No, it isn't what we're talking about. We're talking about making categorical statements that are false. Telling students that you're teaching them a simplified model and there are complications that will be added back later is not lying. But telling them categorically that the simplified model is true and not even talking about the fact that it's a simplified model and there are complications being left out, is lying. And the latter is what the posters I've been responding to are attempting to defend.

> I think there's also a limit to how many times you can say "this is simplified" to students before they feel like they're being pandered to

I have never said that is necessary. Of course it's not. Once you've explained at the outset that you're teaching them a simplified model and there are complications being left out, obviously you're not going to repeat it with every single sentence. Any more than the people who are advocating telling students categorically "multiplication is repeated addition" with no mention of all the complexities lurking underneath are advocating repeating that with every single sentence.

> or that they're being told they're "not smart enough to understand the full theory"

I have never said they should be told that. Teaching the simplified model could be due to nothing more than limited teacher time and knowledge. There's nothing wrong with the teacher honestly telling the students that. Bonus points for encouraging them to investigate further on their own if they're interested.


> No, it isn't what we're talking about. We're talking about making categorical statements that are false.

That's not what we're talking about. Describing multiplication as repeated addition as a way of teaching a new concept to elementary school children is simply not lying.

Your issue is that the fact it is a simplified model is not being explicitly told to students, which is being called lying. While it would be false to say that a simplified model is the complete picture, teachers aren't standing up in class and saying "this is all there is to this subject, no need to learn any more!".

My main issue with your suggestion is that young students simply aren't going to remember a side comment at the beginning of their classes that this isn't the full picture -- so you will either have to repeat this regularly (which will be demoralising and confusing) or there really is no strong benefit to doing so.

You say that the "categorical statement" is not being repeated with each sentence -- but the thing is that when students use or discuss the tools they've learned, they're reinforcing their mental model of how the tool works. So in a way, the simplified model is being repeatedly reinforced in their mind. If you want to counteract it, saying once at the beginning of each class that introduces a new concept "this isn't the full picture" won't help most students overcome the issues they hit when they learn their old model doesn't work for more complicated problems.

> I have never said they should be told that.

You misunderstood what I said -- I said that constantly being told that what they're learning is "not the real theory" (or however you want to phrase) is demoralising in of itself -- it needlessly gives the impression to students that they're not smart enough to understand "the real theory". I never claimed that you said that teachers should say that explicitly.


We lie when when we teach calculus by relying on hand-wavy 'limit' proofs, without grounding students in the foundational aspects of point set topology.

It's much more productive pedagogically to get an intuition for slope and area than it is to get an intuition for compactness and the infinite intersection of open sets, but slope and area are A LIE.


Well, I'd be curious what your first ten sentences to a group of, say, 11th graders would be about Newtonian gravitation, and how those would compare to what you'd say about the same subject to 8th graders.

It seems elsewhere in the thread that you don't consider it lying if one gives a general disclaimer that models aren't perfect, but I wonder whether or not that general disclaimer wouldn't inoculate the idea that multiplication is repeated addition? It's an imperfect model that super useful for all the numbers available to students when they learn what multiplication is. And I wonder further whether there's not an implicit disclaimer that what you're learning isn't the final word inherent in the structure of the educational system?


Explaining the structure of an atom without having to explain atomic orbitals and standing waves. Explaining classical mechanics without including a bunch of caveats about relativistic speeds.


> Explaining the structure of an atom without having to explain atomic orbitals and standing waves.

My high school chemistry teacher had no problem explaining this to me, when teaching the periodic table of the elements, without telling any lies and without going into the details of the quantum mechanics involved. The Pauli exclusion principle and a general statement that the details of the quantum mechanics were out of scope for that class was enough.

> Explaining classical mechanics without including a bunch of caveats about relativistic speeds.

My high school physics teacher had no problem explaining classical mechanics including the caveats. The caveats took only a few minutes early in the semester. What's the problem?


I remember my High School chemistry lesson from the 90's clearly explained we were working with historical models, we talked about nature of the models developments and the experiments that led to them.

We started with the JJ Thomson "plumb pudding model"

Then we learnt about Rutherford and the gold foil experiment which invalidated Thomson's model.

Then we learnt about emission spectrum and the Bohr model which invalidated Rutherford's model.

The whole time it was clear that nothing was "settled" the models were useful at explaining the observed phenomena but were incomplete.

Same thing in physics. We started with debate about nature of light and examined things like lumniferous aether and Michaelson Morley experiment, double slit experiment etc. Then Maxwell and electromagnetism leading to Heinrich Hertz and the photoelectric effect, which led to Planck and Einstein.

I certainly never thought I was being lied to. We were treading along the same path as those who had came before.


> I certainly never thought I was being lied to.

That's because you weren't. You said:

> The whole time it was clear that nothing was "settled" the models were useful at explaining the observed phenomena but were incomplete.

Which is exactly what I think should be told to students when a simplified model is being taught. But the people I've been responding to are advocating for telling students the simplified model as if it were exactly correct and covered all cases. That is what I am saying is lying.


What about earlier than high school? I learned about both of those things much earlier.


Why would you explain classical mechanics at all? It's an inaccurate simplification.


It's much simpler to compute answers with classical mechanics, and the answers are accurate enough for many practical purposes. As the saying goes, all models are wrong but some are useful.


Classical mechanics covers the vast majority of the interactions in day to day life people will have. There is a reason it’s “classical mechanics”.


"When they performed [this experiment] at [experimental accuracy] they observed [that result] which makes them think [atomic orbitals and standing waves]."

Someone who thinks they understand physics without considering experimental accuracy doesn't understand physics.


The goal of primary education isn't to understand any particular thing, it's to provide the intellectual training to understand anything. Someone doesn't need to leave middle school or even high school "understanding physics", but with a base for future understanding. The Bohr model is more than sufficient to help understand chemical reactions.

People seem to be interpreting "lie-to-children" as meaning "[you must] lie[ ]to[ ]children". I don't think there's anyone who thinks that children should be actively deceived into not knowing about quantum mechanics, just that it's OK to use simplified explanations as one step in the process of learning.


It costs nothing to tell someone: "I'm going to teach you one way of thinking about this, but there are other ways you will learn later".




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