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Rumsfeld’s Known Unknowns

Rumsfeld’s Known Unknowns is a concept made popular by former Secretary of Defense Donald Rumsfeld.

It is part of a broader theory about the influence knowledge has on strategic thinking.

It first came to the public’s attention when Donald Rumsfeld used it during a Department of Defense news briefing on February 12, 2002, to answer a reporter’s question about the administration’s failure to uncover weapons of mass destruction in Iraq.

Here is the answer how it was given by Donald Rumsfeld himself:

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.

Years later, in Errol Morris’ documentary The Unknown Known, and on The Late Show with Stephen Colbert, Rumsfeld went on to explain that the third category, the unknown unknowns…

…are the ones that get you.

For the sake of simplicity, I am renaming what Wikipedia calls “There are known knowns” into Rumsfeld’s Known Unknowns Theory.

The aim of this article is to expand the theory and to present a different conclusion.

Let’s first revisit the elements of Rumsfeld’s Known Unknowns theory.

The elements are as follows:

Known Knowns

Known knowns are things we know that we know.

A person familiar with basic arithmetic knows that 2 + 2 equals 4.

The second element is:

Known Unknowns

Known unknowns are things we know that we do not know.

When asked for the square root of infinity, a person can reasonably assume this is something they don’t know.

The third element is:

Unknown Unknowns

Unknown unknowns are things we don’t know that we don’t know.

This third category is where things get tricky.

Unknown unknowns can only be categorized as such for as long as the person is unaware what it is he or she is supposed to know but does not know. The moment the what is revealed to the person, it would inevitably fall under one of the two categories above.

This category is better described simply as Unknowns.

Unknowns are relevant only if they impact the outcome of a decision adversely. Taking our first example, if someone hands you a piece of paper with 2 + 2 written on it and asks you for the answer you would answer 4. But what if they tell you your answer is incorrect and that they forgot to hand you the rest of the piece of paper which completes the operation to read 2 + 2 x 3 = ?

You did not know x 3 was part of the problem. You gave the wrong answer only because you were asked the wrong question.

But what if you were asked the right question and still gave the wrong answer? More on that later.

Strictly from a logic stand point, this category does not reflect adversely on the person giving the answer.

This is where I find it necessary to expand the theory unto a fourth and most critical category.

The fourth new category is:

Unknown Knowns

Unknown knowns are those things we think we know but we actually don’t know.

This is the most dangerous category!

The information is still unknown but the person thinks he or she knows it.

This one is a bit harder to handle because the responsibility for an erroneous outcome falls on the person who made the decision.

When you are certain 2 + 2 is 5 and base your calculations on that you will get an erroneous outcome.


In strategic thinking:

Known Knowns yield correct outcomes.

Known Unknowns should not yield any outcome.

Unknown Unknowns cannot yield any outcome.

Unknown Knowns always yield incorrect outcome.