Fire and Ice

When we don't know but pretend to know we get in trouble.  Richard Fernandez at Belmont Club discusses the pretend knowledge the led to the suspension of air travel in Europe after the volcano erupted.  He quotes comments by Donald Rumsfeld that I consider some of the smartest ever made (but for which he was ridiculed in the press)

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.

It's when you don't know what you don't know that you get into real trouble.