A paragraph from “Jonathan Strange and Mr. Norrell”, which I am still reading.
“But in the end,” added Dr John, “it is by the imposition of his will upon his patient that the doctor effects his cure. It is the forcefulness of the doctor’s own character which determines his success or failure. It was observed by many people that our father could subdue lunatics merely by fixing them with his eye.”
“Really?” said Strange, becoming interested in spite of himself. “I had never thought of it before, but something of the sort is certainly true of magic. There are all sorts of occasions when the success of a piece of magic depends upon the forcefulness of the magician’s character.”