June 20, 2018

Unknown knowns1 and the Gell-Mann Amnesia effect

When I read the news, I accept everything as it’s written as fact. I soak up geopolitics and stock analysis, questioning nothing until I encounter an article about Net Neutrality. And then I shake my head, because the article is egregiously wrong. The article will lack nuance or, worse, will completely mix up the motivations of the subjects involved.

But then, after being exposed for the consensus-driven drivel it is, I’ll turn the page and go right back to taking every sentence I read at face value.

Michael Crichton called this the Gell-Mann Amnesia. Often, the article is so wrong it actually presents the story backward—reversing cause and effect. I call these the wet streets cause rain” stories. Paper’s full of them. In any case, you read with exasperation or amusement the multiple errors in a story, and then turn the page to national or international affairs, and read as if the rest of the newspaper was somehow more accurate about Palestine than the baloney you just read.” 2

I think Crichton is right, but I don’t think it’s because we have short-term amnesia.

I think it’s because we don’t know what we know.

We all seem to have the tendency to think that whoever we’re talking to knows what we know. The reason we assume other people know what we know is because assuming the opposite - that other people don’t know what we know - is hard work.

For example, it’s hard for a computer scientist to describe a database to a kindergartner. It’s not that a database is a complicated concept, but instead it’s because we don’t know what a kindergartner’s reference point is. Do they know what a garage is? How about a warehouse? Can I mention arrays?”

With kindergartners, it’s obvious they don’t know everything we know. But for people our age, and certainly for people who are paid to write Big And Fancy Articles, we assume they know at least what we know. If we didn’t assume that other people share our knowledge, then communicating would be an order of magnitude more difficult. We’d spend our whole day trying to explain databases to kindergartners.

Pop culture has termed this phenomenon You don’t know what you know.”

There are at least two negative consequences of ignoring our unknown knowns.

The first is that we share our ideas less. If I read something, and have an insight, my first reaction is usually, Everybody else has already thought of that.” The reality is few people come to the same conclusions as any of us do. Yet I struggle to write posts or mention ideas because I assume everybody else has already considered them.

The second negative consequence is intellectual envy. I get envious of people when they post interesting insights. When somebody Tweets something thought-provoking, I am in awe of the concept. I begin to feel intellectually inferior because I assume that 1) the author knows everything that I know, and 2) they’ve added a new and original thought on top of everything I already know.

We are so quick to discredit ourselves. We are quick to forget what we know. And because we don’t know what we know, then we assume everybody knows everything we know.3

It’s a small subtlety, but it inhibits us.


  1. There are known knowns. There are known unknowns. There are unknown knowns. And there are unknown unknowns.” Donald Rumsfeld

  2. Briefly stated, the Gell-Mann Amnesia effect is as follows. You open the newspaper to an article on some subject you know well. In Murray’s case, physics. In mine, show business. You read the article and see the journalist has absolutely no understanding of either the facts or the issues. Often, the article is so wrong it actually presents the story backward—reversing cause and effect. I call these the wet streets cause rain” stories. Paper’s full of them. In any case, you read with exasperation or amusement the multiple errors in a story, and then turn the page to national or international affairs, and read as if the rest of the newspaper was somehow more accurate about Palestine than the baloney you just read. You turn the page, and forget what you know.” -Michael Crichton

  3. Even people on completely different ends of the intellectual spectrum forget this about each other. It would be helpful in these contexts to remember that we all have different life experiences. I learned something new about my brother’s childhood last week. I’m sure he assumed I knew that tidbit all along.


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