Feynman wisdom is that you don’t truly understand something until you can explain it to a newcomer.

This gets confused with two seemingly similar claims, however, both of which are (IMO) wrong.

In particular, it doesn’t mean that if you can explain X to a newcomer, that X is true! (Even if the explanation is convincing.)

Nor does it mean that someone who explains something to you understands it.

Knowing, understanding, and explaining are all linked—but in complex ways (the subject of our currently-pinned cog sci paper).

Feynman is focused, in particular, on explaining theoretical physics—a major post-war experience for him being the Feynman Lectures on Physics.

Physicists (at least before the 1990s) got very comfortable with the idea that truth was mathematical consistency (+ mild matches to data). The main barrier after that was simply understanding; a good test of the latter was explanation.

The era of popular physics was a virtuous cycle. Physicists got it right, and made amazing strides by understanding their mathematics; this enabled them to explain revolutionary ideas to the public, who (rightly) celebrated them. We take great pleasure in explanations.

Call this the First “I fucking love science” Era (IFLSE1). The pattern transferred over to evolutionary biology, in Dawkins’ 1970s Selfish Gene, a masterpiece that was blurbed as “the kind of writing that makes the reader feel like a genius”.

IFLSE1 was a good time. But (Goodhart’s Law), we began to optimize for a proxy for truth (the feeling of having something explained), rather than truth itself.

This led to a degeneration: the IFLSE2. We began to confuse people who could explain things with people who understood them; and being able to understand something with knowing it was true.

The best example of IFLSE2 is the pseudo-evolutionary psych world, which will, for some people, never get old.

If you confuse understanding, explanation, and truth you will often come a cropper. Traders know this, and it’s a reason why @nntaleb was such a revelation (for some). Fat Tony doesn’t care about the quality of your explanation.

But in many things—indeed, in my opinion, the most important things—we aren’t kicked in the ass by reality enough. People believe ridiculous things simply because they are part of things that (look like) good explanations, and that give a feeling of understanding.

A million times yes! https://twitter.com/justinowings/status/1316939414157824000?s=20

Another problem comes from the TED talk era, which has infected university teaching. Students are given the task of evaluating professors, and use the explanation heuristic.

Narratives are often very explainy. A satisfying story includes an explanation. Comedians play with this (Dan Dennett’s _Inside Jokes_ is one version of this thesis). A joke is a story with (inter alia) a surprising explanation.

This is why a student feels like he’s learning more from Joe Rogan than his mumbly stats TA. Even worse, he comes to believe that Rogan knows more than his stats TA.

Joe is IFLSE3. Bad science journalism is dying, because people can’t read another airport summary of social psych—it’s not worth it, when you have a comedian who can provide the same feeling with more charisma.

I remember the first time I was with a truly great explainer of quantum field theory (I won’t embarrass this person by naming names). It’s utterly amazing, moving experience. BUT!

I’m sure I had encountered many great explainers of QFT before that point. I had a year in front of Sidney Coleman! But I didn’t understand it yet, and so it washed over me. Physics itself is a great teaser apart...

We all knew the guy (usually a guy) who could explain why the answer on the problem set was the right one—often in a super-satisfying way. But he was rarely the one who got it first (found the key to unlock it).

This is a big danger, both intellectually and morally, because it is tempting to judge truth or understanding on the basis of how good the person is at explaining.

Socrates (paging @Plato4Now!) teases these things apart very well and in different ways over the course of the dialogues. He is often in the business of puncturing explanations—things that everyone around him considers satisfying.

Dialectic replaces explanation with (at different points) aporia, recollection, and insight. The IFLSE3 rejects the first as weakness (or even, in coded form, effeminate), the second as unscientific, the third as undemocratic.

I imagine pre-Socratic Greece as an explanation-saturated world; a time before both dialectics and empiricism. Socrates doesn’t come to *explain* things to Athens, but to put explanation in its proper place, to have it guided by yet deeper matters.

In the end, perhaps the skill Socrates urges on us is a sensitivity to the differences between the feeling of understanding something, of having it explained, and of knowing it to be true.