I don't see how understanding the brain can be achieved in any complete way. Usually x understands something simpler than x, and simpler by orders of magnitude at that (furthermore, something which is possible to be formed as a concept by x and translated to that system). Usually when people speak of "understanding" such objects, they mean it in a very limited and specific, isolated or fragmented and supposedly self-contained context, a bit like claiming that one understands movement because (in some context) specific formulae can be used. But movement itself isn't inherently split from anything else in the material world, which world is not limited to what is picked up by an observer.