It’s an epistemological fact—we don’t know what we don’t know. Or, as Donald Rumsfield put it:
“Reports that say that something hasn’t happened are always interesting to me, because 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. And if one looks throughout the history of our country and other free countries, it is the latter category that tend to be the difficult ones.”
Deconstructed, we have four categories of knowledge:
– Known knowns: “the things we know we know”.
– Known unknowns: the things we know we don’t know.
– Unknown unknowns: the things “we don’t know we don’t know”.
– Unknown knowns: the things we don’t know we know.
The most obvious application of this categorisation of knowledge is in the arena of risk management. For example, when mega structures are built large redundancies are engineered in to mitigate what’s contained in the “unknown unknowns” bucket. A bridge isn’t just capable of supporting the weight it’s expected to support on a day-to-day basis—it can hold way more. It is also designed to be resistant to static and dynamic forces whose probability of being borne are considered to be molecular. When a bridge is conceived average risks and tail risks are kept in mind.
Another example of the mindfulness of unknown unknowns is found in the gaming industry. Ever wonder why developers have public betas? It’s simple. Developers can’t predict what millions of people simultaneously playing their game will 1) collectively do to the infrastructure of their product and 2) individually do to the embedded mechanics. So they open up a beta and respond to the issues that come up. This is how they find out that the servers they thought could handle the player load can’t and how they discover software glitches and exploits that players accidentally or deliberately use to break the game.
However, a normal person doesn’t have to build big things that are vulnerable to human activity and the whims of the nature or release a product simultaneously to millions of demanding, inventive and mercurial fans. But a normal person does have to make decisions and think. So allow me to rephrase the axiom I opened with:
We don’t know what we can’t think.
If you are born completely deaf, there is no way you can understand what a piano sounds like. Because you can’t hear and have never heard, you have no reference points or similarities to use as ingredients for your imagination. Sounds are a blindspot. Put another way. The thoughts I can think are an infinitesimally small subset of all the thoughts I could possibly think. So isn’t it likely that, no matter how rigorous and inclusive I construct my decision making process to be, I’ll still overlook some very important factors?