Understanding vs. Communication

Thursday, March 08, 2018

Photo by Tra Nguyen on Unsplash
Jason Kottke asserts in the title of a blog post the following: "If you can't explain something in simple terms, you don't understand it." With one reservation, I am inclined to agree with the sentiment, given the ample evidence provided from the teaching of Richard Feynman and the methods Apple uses to evaluate its own engineers. For example, Kottke quotes the following from Feynman's Lost Lecture:
Feynman was a truly great teacher. He prided himself on being able to devise ways to explain even the most profound ideas to beginning students. Once, I said to him, "Dick, explain to me, so that I can understand it, why spin one-half particles obey Fermi-Dirac statistics." Sizing up his audience perfectly, Feynman said, "I'll prepare a freshman lecture on it." But he came back a few days later to say, "I couldn't do it. I couldn't reduce it to the freshman level. That means we don't really understand it."
Well, if someone like Richard Feynman is saying this, and one of the world's most successful businessmen concurs, what else is there to say?

This: Feynman has gauged his audience. He has come up with a reasonable estimate of what his audience will regard as "simple." This is no mean feat, and, through my scientific training, I am acquainted with more than a handful of people, including myself, who have had difficulty doing this and, consequently, had to learn how to communicate their knowledge more effectively. Entire books have been written on the subject of effective communication because what Feynman makes look so easy is hardly a trivial matter. (Judging audience context is hardly the only skill, either, but it is most relevant to crafting a simple explanation: e.g., What can I take for granted that they know? How motivated are they about this subject?)

This is not to say that this isn't a good rule-of-thumb for judging a person's understanding of a subject: It's just that the applicability of the rule to an individual has to account for how well that individual understands (a) judging an audience and (b) expressing himself.

The title is excellent -- for those who know that the person whose knowledge they are evaluating has good communication skills. But it has to be held in context: A poor explanation might simply show that someone needs work on communication skills, particularly if that person is young or is a novice in his field. I have been guilty of thinking someone else doesn't know what they're talking about, when the problem was really ignorance of another sort: of communication skills.

-- CAV


Steve D said...

'Well, if someone like Richard Feynman is saying this, and one of the world's most successful businessmen concurs, what else is there to say?'

Isn't that making an assumption about reality; that it must be simple? What if it isn't?

And at what point does a simple explanation become not so simple. That may depend on the intelligence of the person receiving the explanation.

I think reality is logical and consistent; that fundamental laws exist (although we may not know what they are yet). I don't know if there is any fundamental principle demanding simplicity. Although to be honest, Occam's razor appears to work at least most of the time and the most of greatest discoveries to date have been surprisingly....simple.

Gus Van Horn said...


That's a good question, but I think the answer depends on what "simple" means.

Man's great advantage over the beasts is his ability to conceptualize, to omit nonessential details at any given level of abstraction.

Cancer, for example, is a very complex topic, but (to quote the sage Wikipedia), we can accurately describe it as, "a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body." From there, depending on the level of sophistication of the audience, we can explain in more detail, mentioning genetic mutations, the role of genes in encoding proteins, the roles of proteins in the cell, failures in the cancerous cells to communicate with normal cells, and so on. And each of these topics is itself complicated.

At the level of needing to know what cancer is, as opposed to a broken bone or a cold, the short description is enough for most people. It is correct, but lacks the detail needed to study or treat cancer. But those needing such details will have (or need to acquire) the more detailed information.

Perhaps a better example is color. What is blue? We can point to that one and have an explanation adequate for most purposes, but many scientists study various aspects of sensory perception, including the nervous system, optics, the nature of light, and how light interacts with various types of matter.

Perhaps a way of re-phrasing Feynman might be, "If I can't explain it in a way appropriate to any audience, I haven't adequately conceptualized it."


jacobeking said...


Great article and comment.

Building off the connection between "simple" and "adequately conceptualized" and using Objectivist epistemology, I do think "simple" means well-defined, which means distilled to essentials.

For example, from my academic and flight training, I could go on for an exasperating length about how complicated air flow is around a helicopter's main rotor. I could describe it from multiple perspectives, or models, each of which is useful, but none of which would mean anything to someone untrained in rotary aerodynamics. If my nine-year old asked me how helicopters work, I would say, "the main rotor holds the helicopter in the air against its weight by making the air pressure below the rotor higher than the air pressure above the rotor." With time I might be able to concoct an even simpler description.

When asked why helicopters require less power to hover near the ground than when higher, the only simple answer is "nobody really knows." We have a name for it (ground effect), but the phenomenon is not well-enough understood to reduce it to essentials.

To me, the skill is in simplifying without falsifying. Reducing an object or process to its essentials without creating misunderstanding.


Gus Van Horn said...


Thanks for the additional example.


Dinwar said...

My main problem with this sort of thing is that it places the burden on the speaker. In our society, I don't think the speakers are the problem. The audience is. At some point the audience has to attempt to understand the material; if they don't, you will never get them to understand it, no matter how simple you make your explanation.

Gus Van Horn said...


You'll always have this problem, given a big-enough audience. There will also always be people for whom what you say that is correct and good will be obvious. For the purposes of crafting a lecture or written communication, one has to ignore both groups.