"Contrariwise," continued Tweedledee, "if it was so, it might be; and if it were so, it would be; but as it isn't, it ain't. That's logic."

Over the past few years I have heard a reasonably famous quote from a controversial character being bandied around by people as an example of political nonsense. Without wanting to get drawn into the relative merit (or otherwise) of one Donald Rumsfeld, I cannot help but feel that he gets a raw deal on this score.

You see, I have never really understood why people think it is nonsense. I am not sure whether my brain is hardwired to think in a convoluted and ambiguous way (it could be true, I have been accused of this, and I have also spent time locked in rooms with French post-modern feminist thinkers), but from the moment that I heard it, I couldn't see the fuss made about the quote. it seemed to make perfect sense to me right off the bat.

Let's go over the quote again before I move on:

...there are known "knowns". There are things we know that we know. There are known unknowns. That is to say there are things that we now know we don't know. But there are also unknown unknowns. There are things we don't know we don't know. So when we do the best we can and we pull all this information together, and we then say well that's basically what we see as the situation, that is really only the known knowns and the known unknowns. And each year, we discover a few more of those unknown unknowns.

Press Conference at NATO Headquarters, Brussels, Belgium, June 6, 2002

There it is. Simple really. Straightforward when you think about it. Perhaps not as succinct as we could crunch it down to, but probably concise enough given the universality of the idea. To break it down, I am going to try and use the example of alcohol and public policy.

1. Known 'knowns'. This is the easiest part. For example, we know that a lot of people drink alcohol, and that some demographics drink more than others. We have collated plenty of hard data on this.
   
2. Known unknowns. Now, we know about quite a few of the factors that influence why certain people drink, and why people drink the way that they do or why people drink the quantity that they do. But we also know that there are other factors that appear to influence behaviour in one way or another that we do not really understand (for example, why do some girls binge more than others if, demographically, they are the same?). However, in a public policy sense, we at least know that we do not know. Thus, we can try and find out.
   
3. Unknown unknowns. Who knows? If we knew them, we'd know them. For example, in the last few years some researchers have explored the notion that people are genetically predisposed to consuming alcohol at risky levels. That was not really foreseen years ago. As Mr Rumsfeld says, there are always things that we are not aware that we don't know. The best that can be done about this is be aware of that fact ("we don't know everything"), and be prepared to react when we discover a few more of those unknown unknowns (that is, when we become aware of the blind spots in our thinking).
   

See, clear as mud!