What subject are you most ignorant of?

It's an big world out there, there is always something to learn...it is the challenge of our lives I think to be continually learning.  I was talking with Dr. John Ross one time, if you don't know who he is, he was chosen at one time the ambassador of the Native American Sioux..for the United Nations..well, anyway, I had told him that I read that the human mind is able to accept the knowlege of an three story library, upon which after absorbing so much information, one readily  evolves into an embodiment of "light" soul...and I asked him if he thought that was possible. He said that he felt one reason many learned people do indeed seem to beable to do things beyond just physical means in the world, such as out-of-body communications for example, but he'd never met anyone that had went completely over as of yet permanently...but he thought it "perhaps" an possiblity. Interesting concept though as to knowledge in general I thought.