Not knowing what you don't know

This is a very valuable distinction to know:

The difference between knowing what you don't know and not knowing what you don't know.

Examples:

Knowing what you don't know: I don't know about calculus. BUT I *know* I don't know about calculus. I know calculus is a type of mathematics, and I know I don't know anything about it. The same with car engines. I don't know anything about car engines, but I know I don't know anything about car engines.

Now...

Not knowing what you don't know. Or, the saying, you don't know what you don't know: an example would be things in the Work, like Self-Remembering. Before we learn of self-remembering we're walking around in waking sleep, and we don't know it. We don't know what we don't know. 

I always found the saying interesting, but I never pondered it. You don't know what you don't know.