The Rumsfeld filter

Apr 12, 2020

It is well over a year since the first post on this blog.  I had intended it to be monthly or maybe happen once every two months.  Ah well, most of the time that I wasn't spending writing blogs I was sciencing, so I'll let myself off the hook.  However, for various reasons, this seems like a good time to relaunch the effort and  to try to stick to something more like the schedule I had in mind at the outset.

In that first post, one of the points I wanted to make was that too much disciplinary border security in the landscape of science leads to our collective effort, overall, not being able to address complex, multi-dimensional real-world problems; from food production, to environmental stewardship to biosecurity.  I still believe that's true in general, but the SARS-coronavirus-2 pandemic, and the discourse about the virus and the disease it causes, have forced me to acknowledge that there are times when one wants the reassurance that the person talking is a true subject-matter expert.

The coronavirus pandemic has put epidemiology in the headlines.  One of the groups of  tools we have at our disposal to limit the spread of the virus are collective action changes in behaviour (distancing and wearing masks) that have complex social and economic side-effects.  You would think that as an epidemiologist who has spent a lot of time thinking about how the social sciences can be used to better inform how we manage disease, I'd be only too happy to jump in and start offering expert opinion; especially since, in the ordinary way of things, I don't think we should be too intimidated by disciplinary boundaries. Appropriating useful tools from whichever scientific tribe has been bright enough to invent them and putting them to use in new fields, is a good way to make progress. But there is nothing ordinary about the way things are at the moment, and the potential for ill-informed comment to do serious harm has perhaps never been greater. So, even though I study disease dynamics and I spend a lot of time trying to understand human behviour in relation to disease outbreaks, none of that experience is with diseases anything like COVID-19, and I lack the basic knowledge about the biology of this type of virus to think that I'm qualified to talk publicly as "an expert" about what is likely to happen; so I don't.

Unfortunately, a second epidemic, of misinformation and poor information, has grown up around the coronavirus outbreak, at least in part because people who don't know enough about the biology of this type of pathogen, (or epidemiology in general, it seems) apparently feel no qualms about publishing opinion pieces and misleading reworkings of the available data.  Lesson learned; interdisciplinarity needs sensible constraints or we run the risk of succumbing to something like a professional Dunning-Kruger effect.

So, I've got a conflict to resolve.  On the one hand, I want to extol the benefits of fearless interdisciplinarity, but I also want to guard against the risks of non-experts talking with apparent authority on subjects about which they lack sufficient knowledge.  Help might be available from an unlikely source.

Ex Secretary of Defense Donald Rumsfeld made a statement about knowledge during a briefing that has passed into modern folklore.  The impish crew at took Sec Rumsfeld's words and arranged them into the form of a poem:

The Unknown
As we know,
There are known knowns.
There are things we know we know.
We also know
There are known unknowns.
That is to say
We know there are some things
We do not know.
But there are also unknown unknowns,
The ones we don't know
We don't know.

Apart from the almost Zen-like (who knew?) quality that the poem reveals in the words, seeing them in this form makes it obvious that Sec Rumsfeld was making a valuable point about epistemic states.  To make this even clearer, I'll employ a much-loved tool of the social sciences - the two-by-two table:

  Knowns Unknowns
We know Known knowns Known Unknowns
We don't know Unknown knowns Unknown unknowns

The world is divided into two classes of things - Knowns and Unknowns - that form the columns of the table.  Our state of knowledge about each of those classes is represented by the rows, so the table filters the world into four possible states of affairs.  There's an irony in the fact that Sec Rumsfeld apparently only knew about three of the four possibilities (the ones in brown). The irony deepens when we realize that the class he didn't mention were the unknown knows - the things we know, but don't know that we know.  Since he knew the other three, the fourth was available by elimination; in a sense he knew it, but didn't know he did (apparently).  Anyway, so far so self-referential, but how does this help with resolving the conflict between interdisciplinary exploration and unqualified commentary?

When launching into a new interdisciplinary adventure, we can ask ourselves what the balance of our knowledge is among the four outcomes of the Rumsfeld filter.  With luck, there's some stuff we already know and we know that we know it, so we can build out from that safe ground in the upper left cell.  The other cell in the first row, represents stuff we have heard about but not yet learned. Chances are we can make headway here, by reading and through interaction with subject matter experts.  In other words, this is the stuff we know we need to learn.

If there are things in the lower left cell they can sometimes lead to happy moments in interdisciplinary work.  Supply/demand relationships?  Hey! Turns out that they're regulated feedback loops. Cells have those by the bucket-full.  Look at that we knew some economics without knowing we knew it.

It you suspect that the bottom right cell is richly populated then you need to proceed with caution and ask a lot of questions of people who know about the thing you're interested in.  If you suspect that the subject that you've been invited to talk about is largely in the bottom right cell of your world, then it might be a good idea to pass the invitation to someone else, even if one day everything that is in that cell today, ends up in the top left cell.

Heading out of the long narrow swale of your own discipline to visit another valley in the scientific landscape?  Remember to pack your Rumsfeld filter.

By Neil McRoberts
Author - Professor