I just received this in my mail:

He who doesn’t know he doesn’t know is stupid. 
          Avoid him.
He who doesn’t know he knows is asleep.
          Wake him.
He who knows he doesn’t know is untrained.
          Train him.
He who knows he knows is wise.
          Follow him.

 

Really? 
I prefer a different approach…

 

He who doesn’t know he doesn’t know is innocent.
          Leave him be.
He who doesn’t know what he knows is unsure.
          Comfort him.
He who knows he doesn’t know is wise.
          Help him and both of you will learn something.
He who is convinced he knows anything is conceited.
          He is the one you need to avoid.
          Widely.