There is a kind of explanation that I think ought to be a cornerstone of good pedagogy, and I don't have a good word for it. My first impulse is to call it a historical explanation, after the original, investigative sense of the term "history." But in the interests of avoiding nomenclature collision, I'm inclined to call it "zetetic explanation," after the Greek word for seeking, an explanation that embeds in itself an inquiry into the thing.

Often in "explaining" a thing, we simply tell people what words they ought to say about it, or how they ought to interface with it right now, or give them technical language for it without any connection to the ordinary means by which they navigate their lives. We can call these sorts of explanations nominal, functional, and formal.

In my high school chemistry courses, for instance, there was lots of "add X to Y and get Z" plus some formulas, and I learned how to manipulate the symbols in the formulas, but this bore no relation whatsoever to the sorts of skills used in time-travel or Robinson Crusoe stories. Overall I got the sense that chemicals were a sort of magical thing produced by a mysterious Scientific-Industrial priesthood in special temples called laboratories or factories, not things one might find outdoors.

It's only in the last year that I properly learned how one might get something as simple as copper or iron, reading David W. Anthony's The Horse, the Wheel, and Language and Vaclav Smil's Still the Iron Age, both of which contain clear and concrete summaries of the process. Richard Feynman's explanation of triboluminescence is a short example of a zetetic explanation in chemistry, and Paul Lockhart's A Mathematician's Lament bears strong similarities in the field of pure mathematics.

I'm going to work through a different example here, and then discuss this class of explanation more generally.

What is yeast? A worked example

Recently my mother noted that when, in science class, her teacher had explained how bread was made, it had been a revelation to her. I pointed out that while this explanation removed bread from the category of a pure product, to be purchased and consumed, it still placed it in the category of an industrial product requiring specialized, standardized inputs such as yeast. My mother observed that she didn't really know what yeast was, and I found myself explaining.

Seeds, energy storage, and coevolution

Many plants store energy in chemicals such as proteins and carbohydrates around their seeds, to help them start growing once they're in wet ground. Some animals seek out the seeds with the most extra energy, and poop the occasional seed elsewhere. Sometimes this helps the plant reproduce more than it otherwise would have; in such cases, the plant may coevolve with the animals that eat it, often investing much larger amounts of energy in or around the seed, since the most calorific seeds get eaten most eagerly.

Humans coevolved with a sort of grass. If you've seen wild grass, you may have observed stalks with seed pods on them, that look sort of like tiny heads of wheat. Grain is basically massively a grass that coevolved with us to produce plump, overnourished seeds.

Energy extraction

Of course, there's only so much we can do to select for digestibility. Often even plants that store a lot of surplus energy need further treatment before they're easy to digest. Some species evolved to specialize in digesting a certain sort of plant matter efficiently; for instance, ruminants such as cattle and sheep have multiple stomachs to break down the free energy in plant matter. Humans, with unspecialized omnivorous guts, learned other ways to extract energy from plants.

One such way is cooking. If you heat up the starches inside a kernel of wheat, they'll often transform into something easier to digest. But bread made this way can still be difficult to digest, as many eaters of matzah or hardtack have learned. Soaking or sprouting seeds also helps. And a third way to make grains more digestible is fermentation.

Cultured food

Where there's dense storage of energy, there's often leakage. Sometimes a seed gets split open for some reason, and there's a bit of digestible carbohydrate exposed on the surface. Where there's free energy like this, microbes evolve to eat it.

Some of these microbes, especially fungal ones, produce byproducts that are toxic to us. But others, such as some bacteria and yeasts, break down hard-to-digest parts of wheat into substances that are easier for us to digest. Presumably at some point, people noticed that if they wet some flour and left it out for a day or two before cooking it, the resulting porridge or cracker was both tastier and more digestible. (Other fermented products such as sauerkraut may have been discovered in a similar way.)

Of course, while grain-eating microbes will often tend to be found on grain, allowing for such accidental discoveries, there is no guarantee that they'll be the kind we like. Since they mostly just eat accidental discharges of energy, there also just aren't very many of them, compared to the amount of energy available to them once the flour is ground up and mixed with water. It takes a while for them to eat and reproduce enough to process the whole batch.

Eventually, people realized that if they took part of a good batch of dough or porridge and didn't cook it, but instead added it to the next batch, this would yield an edible product both more reliably (because the microbes in the starter would have a head start relative to any potentially harmful microbes) and more quickly (again, because they'd be starting with more microbes relative to the amount of grain they needed to process). This is what we call a sourdough "culture" or "starter".

(You can make a sourdough starter at home by mixing some flour, preferably wholemeal, with water, covering it, and adding some more flour and water each day until it gets bubbly. Supposedly, a regularly fed starter can stay active for generations.)

Breads are particularly convenient foods for a few reasons. First, grains have a very high maximum caloric yield per acre, allowing for high population density. Second, dry grains or flour can be stored for a long time without going bad; as a result, stockpiles can tide people over in lean seasons or years, and be traded over large distances. Third, a loaf of bread itself has some amount of more local portability and durability, relative to a porridge.

Yeast-specific products

One of the microbes found in a sourdough culture, yeast, has a particularly simple metabolism with two main byproducts. It pisses alcohol, and farts carbon dioxide. Carbon dioxide is a gas that can leaven or puff up dough, which makes it nicer to eat. Alcohol is a psychoactive drug, and some people likes how it makes them feel. Many food cultures ended up paying special attention to grain products that used one or the other of these traits: beer and leavened bread.

In the 19th century CE, people figured out how to isolate the yeast from the rest of the sourdough culture, which allowed for industrial, standardized production of beer and bread. If you know exactly how much yeast you're adding to the dough, you can standardize dough rising times and temperatures, allowing for mass production on a schedule, reducing potentially costly surprises.

The price of this innovation is twofold. First, when using standardized yeast to bake bread, we forgo the digestive and taste benefits of the other microbes you would find in a sourdough starter. Second, we become alienated from a crucial part of the production of bread, to the point where many people only relate to it as a recipe composed of products you can buy at a store, rather than something made of components you might find out in the wild or grow self-sufficiently.

Additional thoughts on explanation

I'm having some difficulty articulating exactly what seems distinct about this sort of explanation, but here's a preliminary attempt.

Zetetic explanations will tend to be interdisciplinary, as they will often cover a mixture of social and natural factors leading up to the isolation of the thing being explained. This naturally makes it harder to be an expert in everything one is talking about, and requires some minimal amount of courage on the part of the explainer, who may have to risk being wrong. But they're not merely interdisciplinary. You could separately talk about the use of yeast as a literary motif, the chemistry of the yeast cell, and the industrial use in bread, and still come nowhere close to giving people any real sense of why yeast came into the world or how we found it.

Zetetic explanations are empowering. First, the integration of concrete and model-based thinking is checkable on multiple levels - you can look up confirming or disconfirming facts, and you can also validate it against your personal experience or sense of plausibility, and validate the coherence and simplicity of the models used. Second, they affirm the basic competence of humans to explore our world. By centering the process of discovery rather than a finished product, such explanations invite the audience to participate in this process, and perhaps to surprise us with new discoveries.

Of course, it can be hard to know where to stop in such explanations, and it can also be hard to know where to start. This post could easily have been twice as long. Ideally, an explainer would attend to the reactions of their audience, and try to touch base with points of shared understanding. Such explanations also require patience on both sides. Another difficulty this approach raises is that plain-language explanations rooted in everyday concepts may not match the way things are referred to in technical or scientific literature, although this problem should not be hard to solve.

In some cases, one might want to forwards-chain from an interesting puzzle or other thing to play with, rather than backwards-chaining from a product. Lockhart seems to favor exploration over explanation for mathematics, and of course there's no particular reason why one can't use both. In particular, the explanation paradigm seems useful for deciding which explorations to propose.

Related: The Steampunk Aesthetic, Truly Part Of You


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Two posts that feel relevant to this, including briefly for now:

Outside the Laboratory

The Steampunk Aesthetic

6Benquo2yThanks for pointing these out. I feel like the class of explanation I'm trying to point to is the narrative complement to some of what you were trying to point to in The Steampunk Aesthetic. I'll add a link to it.

Promoted to curated: I think the question of "what makes a good explanation, and how do humans come to really understand things?" is one of the core questions of rationality. I think this post is a well-written and clear attempt at introducing some important considerations on what makes a good explanation, and I expect most readers to walk away with a slightly improved ability to give better explanations than they were before.

Importantly, in the broader idea-pipeline of LessWrong, I think the concept outlined in this post is still in a relatively early poetry phase, and I would be somewhat hesitant for it to be adopted widely. I think as we develop and analyze the ideas in the post further, I expect we will eventually get something more similar to Eliezer's "A technical explanation of a technical explanation", where we can be more precise and robust in specifying what makes a good explanation, instead of having to rely on vaguer metaphors and individual examples.

(I don't mean to say that this post says the same thing as Eliezer's technical explanation post. I think it primarily talks about different aspects, that are also important. I am only trying to say that Eliezer's technical explanation seems like a good target standard for rigor and robustness)

I agree on the limits of this post - I hope it's a beginning, not an end.

Stories were probably the first information format

Imagine a time before language. The information you get from your environment comes as series of events happening over time. That's the kind of information you're good at integrating into your active knowledge. Now, our blind idiot creator bestows us with language, what kind of information structure is going to allow us to convey information to our conspecifics in a way that they'll be able to digest and internalize? Just the same, a description of a series of events spoken over time, which they may now experience as if those events were happening again in front of them.

And this kind of information is very easy for us to produce. We don't need to be able to assemble any complex argument structures, we just need to dump words relating to the nouns and verbs we saw, in the order that they occurred. Stir in an instinct to dump episodic memories in front of people who weren't present in those memories, and there, they will listen, and they'll get a lot out of it, and now we have the first spoken sentences.

With this in light, if it turns out storytelling was not the first kind of extended speech, I will be s... (read more)

Programmers are often advised to write comments in the code about the intent, what they wanted the code to do, rather than about what the code does.

When you think about it, it makes sense. The code already does what it does, no need to write about that. However, what is the code supposed to do is often unclear, especially when the code is buggy.

This is kind of similar to the yeast example above. The rule is to explain why not how.

To give another example, I am trying to learn statistical mechanics. Not to memorize it but to actually grok it. And it turns out that staring at the equations doesn't help much. I am planning to look into its history to understand what kinds of problems were fathers of thermodynamics trying to solve (something to do with steam engines, I guess) to understand why that specific kind of thinking about the topic is useful.

[P]rograms must be written for people to read, and only incidentally for machines to execute.

— Harold Abelson and Gerald Jay Sussman, Structure and Interpretation of Computer Programs

This quote is correct for many reasons, one of which is that all a computer has to do with a program is execute it; whereas it often falls to humans to modify it, because to us, humans, there exists the concept of “what this program should, ideally, do”. The reason (or, if you like, a reason—though the major one, I would say) why code ought to be clear and readable is in order that humans may be able to (a) evaluate it on the basis of how far the actual program is from what we’d like it to be, and (b) modify the program in order to bring it more into line with the ideal.

This, in turn, gives us a way to respond to the occasional claim that it is not, in fact, necessary that code be human-readable. Clearly, code should be human-readable if there will ever be a case when either (a) humans need to examine it by hand (as opposed to examining it with some automated tools), or (b) humans need to modify it. If this is simply not going to happen (e.g., Java bytecode), then readability is irrelevant.

And n

... (read more)

This post helped me notice a difference I've felt between satisfying and unsatisfying explanations; why Feynman explaining something feels different from Wikipedia explaining something. I love it.

There were two details that you left out that bothered me. At first I felt like I was nitpicking, but then they two coalesced and I felt better describing them.

You say that animals have coevolved with plants, but you I think you should have spelled this out more. You say that the plant puts more energy around the seed, but you don't say that this is a fruit. The point of a fruit is not to be higher energy to than a seed, just so that it is more likely to be eaten (Are there any examples of this, outside of agriculture?). The point of a fruit is to sep... (read more)

7Benquo2yThe second point seems like an important omission if true. Not having known that originally, I notice that based on the model in this post, it seems like the sort of thing that could likely be true. I don't think I explicitly mentioned the neighbor method either, though I think it's another reasonable inference from what I did say. On your second point, it seems like while fruits often store food packages outside the seeds, grains grow a bunch of similar modules with uncertainty about whether they'll be used as the reproductive payload or the calorie surplus that persuades the symbiote to spread the reproductive payload. My guess would be that before explicit agriculture, some grasses did well around humans because there would be the occasional undigested or otherwise scattered seed by accident. Overall it seems like you're pointing at something important on the object level here, and I appreciate the engagement with the *kind* of explanation I was trying to give.
3vedrfolnir2yI'm not a biologist, but I think it would be pretty difficult to tell whether fruits are intended to encourage animals to eat them or to protect the inner seed. But the energy in an avocado is primarily stored as fats, and it's generally thought that they were eaten by now-extinct Central American megafauna. (And it's common to stick avocado seeds with toothpicks to get them to sprout...) There's also the chili pepper, but I don't know if anyone's studied digestion of pepper seeds in birds (which aren't sensitive to capsaicin) vs. mammals (which are). It may be that chili peppers evolved to deter mammalian but not avian consumption because the mammalian digestive tract is more likely to digest the seeds, rather than (as the common explanation has it) because birds disperse the seeds more widely.
3Douglas_Knight2yFor chili peppers, I, too, prefer the second explanation. I think that is the more popular one, eg, appearing in wikipedia []. More specific than digestion, is the theory that it is to avoid the grinding teeth of mammals. I don't know if the specific case has been studied, but the general topic of how much various fruit-eaters digest seeds has been studied. Presumably there is study of how to select cooperative fruit-eaters over defective fruit-eaters. I am confused by your first sentence. What are the alternative hypotheses? Protect the seed from what? Fruit are certainly lousy at protecting the seed from yeast. I claim that they protect the seed from specialized seed-eaters by encouraging consumption by specialized fruit-eaters. Yes, the avocado is a pretty weird fruit, but it's still a soft, wet, easily digestible outer coating around a hard, difficult to digest seed. What light does it shine on the question? Your use of the word "but" suggests that it addresses the first question, but I don't see it, perhaps because I don't know what the first question is.
3ryan_b2yI find the adding fruit method interesting, as I had not heard of it before. I had understood the exposure-to-air method to be both the earliest and the most common, which matches my expectation as all the environments people are in have naturally occurring yeast, but not all of them have fruit to add. For example, traditional sourdough explicitly has just water, flour, and salt. I'm pretty sure the methods of bread making at least in Morocco and Iraq don't involve adding fruit, which I sort of mentally extend across the Arab-speaking world. Because of its similarity I assume the same of naan. Interestingly Iraq (at least the Baghdad area where I have been) is an easy-access fruit environment courtesy of citrus trees. On the flip side, I have seen recipes for different sourdoughs that involve adding grapefruit juice to accelerate the process, but in the context I saw it was just for speeding things up. There is also the habit of adding various leftovers, including fruits, nuts, and vegetables to bread, which would probably have a similar effect.

Thanks for the great reading, I wonder if someone would be interested in writing a zetetic description of a very complex subject, as an exercise of course, to see if such a thing is even possible for very complex subjects or how effective it is. I'm new to the site so sorry if such a request is off topic.

4Benquo2yYou could try.

So the big question here is, why are zetetic explanations good? Why do we need or want them when civilization will happily supply us with finished bread, or industrial yeast, or rote instructions for how to make sourdough from scratch? The paragraph beginning "Zetetic explanations are empowering" starts to answer, but a little bit vaguely for my tastes. Here's my list of possible answers:

1) Subjective reasons. They're fun or aesthetically pleasing. This feels like a throwaway reason, and doesn't get listed explicitly in the OP unle... (read more)

8Raemon2yI think your list is roughly correct. But, put another way that feels oriented better to me: It might or might not be that zetetic explanations are good. But what are the problems that Benquo is trying to solve here and how can we tell if they got solved? * People often learn bits of knowledge as isolated facts that that don't fit together into a cohesive world-model. This is a problem when: * people are confronted with problems that they have the knowledge to solve, but aren't aware that they dopeople are confronted with situations they don't even realize are problems, or worth considering as problems, because they were so disconnected from how their world fits together that they didn't see it as gears.a stronger claim may be that there exists a longterm, high level payoff for having a highly developed ability to integrate knowledge. (Partly because you have a whole lot of accumulated knowledge that fits together usefully, but moreover, because you have the ability to reflexively form theories and test them and use them effectively, which is built out of several subskills. (See Sunset at Noon [] middle sections for my take on that) So the hypothesis here is that: * Most people's pedagogy has room for improvement, in the domain of helping people to connect facts into an integrated world-model, and to build the skill of doing so. * Explanations that include cross domains, historical content, and connecting a concept to anchors that a person can clearly see and understand are a good way to improve pedagogy in this way * I'd perhaps add that that style of pedagogy may be good for the teacher as well as the student.

I'm reading the largely lucid explanation of yeast, but here's the main bits where I got stuck:

Where there's dense storage of energy, there's often leakage. Sometimes a seed gets split open for some reason, and there's a bit of digestible carbohydrate exposed on the surface. Where there's free energy like this, microbes evolve to eat it.
Some of these microbes, especially fungal ones, produce byproducts that are toxic to us. But others, such as some bacteria and yeasts, break down hard-to-digest parts of wheat into substances t
... (read more)
4Benquo2yThe only explanation I have to offer here is a selection effect. Mostly when something is food to us, other creatures compete with us for the food and we want to ward them off. Occasionally we find something that transforms nonfood to food, and encourage it to grow. Crops are one example. Ruminants are another. The microbes that grow on grain are another. It's the breaking up of the wheat kernel in grinding flour that makes more of the energy available (vs the occasional leakage you might expect to happen without human intervention), by opening up the capsules it's in. But water is also needed for metabolism, so until you wet the flour the naturally occurring grain-eating microbes can't take much advantage of this.

So basically, historical explanations. These are frequently a good idea for exactly the reason you say -- a lot of things are just a lot more confusing without their historical context; they developed as the answer to a series of questions and answers and things make more sense once you know that series.

However it's worth noting that there are times where you do want to skip over a bunch of the history, because the modern way of thinking about things is so much cleaner, and you can develop a different, better series of questions and answers than the one that actually happened historically.

Here's why I think the distinction you're drawing can be misleading:

Some "historical" explanations lay out a path to discovering a thing that clarifies the evidence we have about it and what other ways that evidence should constrain our expectations. Other "historical" explanations recite the successive chronology of opinions about the thing, often with a progress narrative.

Some modernized explanations go through a better-than-chronological series of questions and answers that lead you more efficiently to understanding the thing. Others teach you how to describe the thing in contemporary technical jargon.

For both the chronological and modernized approach, the first version is zetetic, the second version isn't.

2Sniffnoy2yThanks, that's a good way of putting it.