Knowledge Is Power

Another Pratchett quote from A Hat Full of Sky:

"Well, couldn't you help him by magic?"
"I see to it that he's in no pain, yes," said Miss Level.
"But that's just herbs."
"It's still magic. Knowing things is magical, if other people don't know them."

And thus our rationale for why doctors and lawyers and such get paid more money than the rest of us, not so much for what they can do, but because of what they know.