I think Atom & Organism pretty much nailed it. It's as if there should be an 'a priori' question - Does anyone understand Richard Feynam? His genius was of a rare sort. His sense of words such as 'knowing', 'understanding', and one his classic phrases, "The pleasure of figuring things out", were not always applied in the conventional manner. For example, he wrote of a student who approached him after class with a question on some subject that Feynman believed he knew as well as he did the back of his hand. After several attempts, the student walked away still confused. Feynman reflected upon this and concluded that his failure indicated that he, himself, did not 'understand' it as well as he had thought. Again, as A & O indicated, I also believe that Feynman's use of 'understanding' was of a deep and profound nature indeed!