Why It's Hard to Explain Things: Inferential Distance

Some people wonder why it takes so long to explain a point. Why can’t I just explain utilitarianism in a couple of sentences, or just one essay? Why do they need to read so much? The answer is because of the problem of large inferential distance which I first encountered in Eliezer Yudkowsky’s essay “Expecting Short Inferential Distances”. I will now, ironically, explain the concept of inferential distance in just one essay.

To start explaining, I begin with an analogy: Imagine trying to explain to a young-earth creationist why evolution is viewed as so obviously true. I don’t do this to say that you’re the obviously wrong creationist and I’m the noble biologist out to explain science to you that you just don’t get because you’re stupid. That’s not an accurate description of where we stand (nor is it an accurate description of where creationists stand). It’s just a good example to explain my point – bear with me.

Anyways, imagine trying to explain to a young-earth creationist why evolution is viewed as so obviously true.

It isn’t so easy. No matter how true evolution is, and how friggin obvious it is to biologists, there just is no one single sentence that would make a young-earth creationist go “Ah ha! I get it! I see the error of my ways! How could I have been so wrong for so long?”. Not even a paragraph can do it, even if it is about something as monumental as how the genetic similarity of animals as confirmed by DNA sequencing clearly creates a neat tree of ancestry.

…Not even a long essay can do it. …Not even a few dozen long essays can do it. …Not even an entire website TalkOrigins.org, containing over one hundred such long essays in defense of evolution, natural selection, and common descent, including many that from my perspective completely skewer any hope of young-earth creationism being considered a serious position, is able to convince a young-earth creationist to change his or her mind.

We might wonder why this is?

How Do We Argue Evolution?

Many people would hypothesize that such young-earth creationists are “impervious to evidence”, “unwilling to see reason”, “too stubborn to understand”, “too stupid to understand”, or “not even care about what is true”. This is perhaps an accurate description of quite many creationists, but not all of them. And some of the other creationists are impervious/unwilling/stubborn/stupid/uncaring for a reason that they can probably be argued out of, even if only in principle.

In fact, I know an intelligent young earth creationist who is just simply mislead by what evolution is, what the evidence for evolution is, or how evolution functions. And I think that there is a path to him changing his views, with a lot of argumentation.

But it would take a lot of argumentation: first we would have to debate whether it is circular to believe in the Bible because the Bible says so, then debate why the Bible should not be considered good evidence about biological fact, then debate why we can accept evidence that contradicts the literal Bible, then debate how this evidence should be understood, then debate why we should go with the most likely hypothesis even if we can’t be absolutely certain, then debate the scientific method, then debate the age of the earth, then debate what evolution is and entails, then debate why biologists believe in evolution, then debate why each and every of many dozen alleged problems of evolution are fallacious or misleading, then clear up a few philosophical misconceptions, and then we might emerge on the other side with an agreement about evolution.

There’s no way to short-cut this. There’s no way that we could get to the bottom of this without perhaps months of discussion. This is why creationists and biologists don’t agree – it isn’t stupidity, it’s just so much prerequisite material needs to be cleared up before we can even begin to discuss the merits of evolution as an explanation for the evidence.

What is Inferential Distance?

Biologists talking to other biologists can easily justify evolution by saying “it’s the simplest explanation” and then providing a few paragraphs of research. But to the layperson, they have close to no idea what it means for an explanation to be simple, or what biologists look for in explanations, why we should care about whether our explanations are simple, or why being the simplest explanation is enough to conclusively justify a theory. They might just see “simplest explanation” as a word that is thrown around, like “magnetism” or “conduction”. They don’t see the massive amount of concepts bundled into the four word phrase.

On the other hand, it’s easy to explain to people why they need to buy a new pair of shoes: both people clearly share the same conception of “shoe” with no disagreement; both people understand clearly that broken shoes are not socially accepted and know what it means for a shoe to be “broken” and what it means to be “socially accepted”. It’s obvious to just point to someone “Dude, your shoes are broken, you should buy a new pair”. It’s not obvious to just point out to someone “Dude, evolution is the simplest explanation, you should no longer be a creationist”.

This is the idea of inferential distance: in many cases, people don’t share the same understanding of concepts or agree in previous lines of argument, and these previous steps need to be addressed before we can get to debate the current step. Often, there are many such steps, and we end up with the extended debate between the creationist and the biologist.

The size of the inferential distance is thus how many steps need to be discussed before we can get to the matter at hand – the size is very small between biologists discussing evolution, but quite large between the creationist and biologist.

And thus the problem of large inferential distance: I need to write many essays one-at-a-time and gain agreement on many concepts one at a time before I can even hope to, for example, convince someone why they should become a vegetarian. The idea of having a reason to be vegetarian sounds not just wrong but outright crazy to some people… that’s because, I would argue, the inferential distance.

My first theory of explanations was taken after Albert Einstein, who famously said “You do not really understand something unless you can explain it to your grandmother.” I thought that I would just study something so hard that I would truly grasp it, and then come up with a few paragraphs so clear and lucid that anyone who read it would just grasp it immediately.

But inferential distance is a real thing – there are some positions which are true, but will take months if not years of discussing material to come to understand, even if the process is as efficient and clear as possible. There’s no way out, no short-cut, no get-out-of-inferential-distance-free card. Those lazy “tl;dr” people just won’t learn, and will be left behind forever.

So I suppose Albert Einstein was right. You indeed don’t truly understand something until you can explain it to your grandmother. But this explanation might take months of discussion, so it probably isn’t a practical test of your skills as an explainer or understander.

But How Can the Distance Be So Large?

Now that we know about inferential distance, I’d like to end with a discussion of how it got to be so large. Why do we live in a world where things take years to explain? This answer is ironically simple and easy to explain: there’s been a long history of knowledge, and it’s all built upon itself.

It takes a lot to truly understand something, because we’ve had thousand of years to learn so much. Back in the times of the Middle Ages, it was easy to understand why the sky is sometimes bluish, because so little was understood about the sky. It would have been easy to become an expert, if only the sum of human knowledge was so easily communicated via the internet, all else being equal. But now to get a complete account, you have to learn about how eyes perceive color, how light works, how refraction works, the composure of the atmosphere, and Rayleigh scattering, each of which involve many subconcepts. Even if you could master one concept in a week, it would take a few months to get it all.

Now imagine it for a more complex topic, like morality, cosmology, or artificial intelligence. It will take years to fully explain it, and there just is no other way to go about it. The good news is that it can be explained, you can master it, if you try and dedicate your life to it. The sad truth is that it will take so much time. There is a sad truth of inferential distance.

We don’t just stand on the shoulder of giants, we stand on a long series of giants standing on giants, standing on giants, standing on giants, standing on giants, standing on giants.

And if you don’t know what the first giant demonstrated to be true, you will have to start learning all the way from the bottom until you can get to the current field.


Author’s Note: An earlier draft of this essay appeared on my old blog.