What Do We Know?
   What is it we don't know?

Sometimes it seems we know,
   Other times it seems we don't know.

There are times it seems we know what we know,
   At other time it seems we don't know what we know.

Then times when we think we know,
   But, we don't really know if we know.

It is when we don't know what we don't know,
   That delivers the crowning blow.