The Phantom Tollbooth
"It will take years to collect all those sounds again," she [the Soundkeeper] sobbed, "and even longer to put them back in proper order. But it's all my fault. For you can't improve sound by having only silence. The problem is to use each at the proper time." (13.17)
"But maybe he doesn't understand numbers," said Milo, who found [the Mathemagician's letter] a little difficult to read himself.
"NONSENSE!" bellowed the Mathemagician. "Everyone understands numbers. No matter what language you speak, they always mean the same thing. A seven is a seven anywhere in the world." (16.43-44)
"That's why," said Azaz, "there was one very important thing about your quest that we couldn't discuss until you returned."
"I remember," said Milo eagerly. "Tell me now."
"It was impossible," said the king, looking at the Mathemagician.
"Completely impossible," said the Mathemagician, looking at the king.
"Do you mean – " stammered the bug, who suddenly felt a bit faint.
"Yes, indeed," they repeated together; "but if we'd told you then, you might not have gone – and, as you've discovered, so many things are possible just as long as you don't know they're impossible." (19.51-56)