Kinds of Things We Don't Know

I have been listening to an interesting Charlie Rose show on the U.S. Intelligence system. It got me thinking about kinds of ignorance. Here are some types:

• Things we can't know. For example, we can't know whether there are intelligent beings in other galaxies. The distances are so great that even if we somehow got a message from another galaxy that implied an intelligent source, that species might no longer still exist.
• There are secrets -- things that are being kept from us.
• There are mysteries.

Al Qaada is keeping secrets from the government of the United States, but the evolution is radical Islamic movements is perhaps more a mystery than a secret. We might be able to work it out, but there is probably no one who really knows what it will be who is keeping that knowledge secret.

• There are things we know, but don't know that we know.

I am getting old enough that there are often things that I know, but can't retrieve at the moment. There are also things that we can figure out without further information, but have never formalized as knowledge. But the key word is "we". There is information embodied in structure and process of groups or organizations that is not explicitly known to any member. There is also information in such groups or organizations that is somewhere such that it can not be brought to bear when and where it is needed.

• There are things we choose not to know.
• There are things we simply have not yet found out.

And of course, there are things we know that are not true.

We don't know what we don't know, and we don't know what we think we know that is not true.

There is also the difference between accuracy (validity of information) and precision (the exactitude of information)