“What we know is not much. What we don't know is enormous.”
“What we know is not much. What we do not know is immense.”
“We don't know what we don't know.”
“The true test of character is not how much we know how to do, but how we behave when we don't know what to do.”
“What we know is a drop, what we don't know is an ocean.”
“It is not so much what we know that is important, as what we are and what we do.”