It's basically like the missions in COD, when you complete several quests and you think your mission is over, then the game throws at you some new information and new quests are added.
Nice hint.
It goes for everything, magic related the wolf did a good job. I'll try to explain it slightly different though.
Laymen know three things about magic: It's up our sleeve, you must have palmed it, and we have very fast hands. Even if none of it is true...they know this much.
If they learn about the double lift they now know this much more. Then they learn about the pass. Then all of the variations of the pass. The more they know the further into the craft they dive, and they realize they know even less then they thought. The more I know, the more I realize I don't understand any of it.
People devote years to the pass, amateurs devote hours and think they have it. The more you know about the pass, the psychology, and the way it's supposed to work...the more you realize you don't understand it at all. Which leads you to doubt what you know about everything.
Good quote. Twain has quite a lot of good work, my favorite is the work he did on Shakespeare, rather, the work shakespeare allegedly did.