“Erudition - dust shaken out of a book into an empty skull”

“It is the contention of Mr Norrell of Hanover-square that everything belonging to John Uskglass must be shaken out of modern magic, as one would shake moths and dust out of an old coat. What does he imagine he will have left? If you get rid of John Uskglass you will be left holding the empty air.”

“An empty skull is the vanitas symbol of modern education.”

“His shelf. Good. Noodle dust. Decaying brain collecting dust. Must insert it back in skull—what was I thinking?”

“Who is to decide which is the grimmer sight: withered hearts, or empty skulls?”

“There is more empty space in the book you're holding, than book. The electrons in the atoms of the book are moving so fast, they give the illusion of solid ink on solid paper. It's not. It's just an illusion. If all the electrons would stop moving for even an instant, the book would not just crumble into dust, it would disappear. Poof”