Knowledge would be specific facts or procedures – hard reliable data. Understanding would be the ability to assemble knowledge into a cohesive interworking structure. What’s interesting is that you might think that understanding can only be developed upon a base of knowledge, but in reality they tend to float freely. You can’t get understanding without first working closely with a lot of base facts, but a generalized understanding can be transferred over to a new knowledge base and anticipate information you haven’t acquired yet, and so pick it up faster. It also scales upward: understanding at one level can be evaluated as a kind of knowledge in order to achieve a higher level of understanding. So knowledge is more foundational, but understanding is more desirable.
ON THE OTHER HAND, nothing can be more frustrating than a conversation in which knowledge and understanding don’t match up. Understanding that ain’t so is much harder to fix than when what you know ain’t so. So when a person with superior understanding (or supposed superior understanding) comes into contact with someone who has a more shallow understanding and a hard grip on the facts…! Let’s just say nobody is going home happy.
… I see him there
Bringing a stone grasped firmly by the top
In each hand, like an old-stone savage armed.
He moves in darkness as it seems to me-
Not of woods only and the shade of trees.
He will not go behind his father’s saying,…