I usually just vomit up the incompletely digested writings of superior minds on my blog. I'm far too cowardly to tackle a foe without some fancier person in my corner.
Today though, I'll try all on my lonesome (though I'm really defending Richard Feynman, who coped fairly well without me).
Feynman once wrote something like, "If you really understand something in physics you can prepare a lecture for first year students on it." I remember being pretty influenced by this and apparently Eliezer Yudkowsky was too cos he says "I believed him. I was shocked to discover it wasn't true (his emphasis)."
Now I know as well as anyone that reading high quality popular science does not, in fact, enable you to understand physics (heaven forbid!), but that isn't what Feynman means! He claims that you should be able to explain the subject to a novice, not that the novice will then understand the explanation, he's only ever mentions his own understanding. In other words, he means that some other expert will think the explanation is impressively deep, because she'll know what Feynman is really getting at with this or that analogy, "It's like a spinning top! Genius!"
This is a pretty common observation. I've heard people saying that they only really understood something after they were required to teach it. I guess the substance behind Yudkowsky's gripe stands because what's going on here isn't really an explanation at all, but he misunderstood what Feynman was getting at.