While reading Wizard and Glass, the fourth volume in Stephen King's Dark Tower epic, I came across this epiphany. What is the difference between The Riddler and The Joker? Roland and his team, in which he calls his ka-tet, are aboard Blaine the Train. They are tasked with a riddling contest.
Blaine is a locomotive with an artificial intelligence, that may be a little damaged at this point. Or as they see it, Blaine's a little crazy. From the city of Lud, set in the post-apocalyptic dimension of Mid-World, the train takes them to Topeka. Though, it might not be the Topeka the reader is expecting. Or is it? It seems to resemble a Kansas from another of King's books: The Stand. Blaine tells them he's going to commit suicide, crashing his self once he gets to Topeka. Obviously, with Roland and his ka-tet on board, he's killing them with him.
Roland offers Blaine an ultimatum. Since the train's A.I. is fond of riddles, if he, or any member of his ka-tet, stumps him before they get to Topeka, then he will let them go. But if they don't, then he continues on his suicide course.
By the end, they realize one thing. That one thing is what brings me to my epiphany. Roland asks thousands of riddles from his boyhood. Growing up, training as a gunslinger in Gilead of Mid-World, there was a riddling contest each year on Fair Day. Even though he remembered every riddle, he never took home the prize goose. It was said because he lacked imagination. Eddie, on the other hand, another member of the ka-tet, grew up on the streets of New York. There wouldn't be a paragraph of Eddie's dialog gone by without a cheesy joke. On page 50 of Wizard and Glass, Eddie tells Roland:
"....jokes were riddles designed to help you build up that overlooked talent....."
While Blaine answered every riddle of Roland's without hesitation, it was Eddie's jokes that eventually broke him down. One theme throughout The Dark Tower is that there are "twins" that live in another dimensions - doppelgangers, if you will. If you look at Roland and Eddie's roles, and personify them, you could see who their twins are in the DC Universe.
The epiphany is this: While the Riddler sharpened Batman's mind, the Joker made him lose his mind. One breaks down easier through anger and then insanity, than with a keen mind. That's why the Joker is Batman's greatest arch-nemesis, rather than the Riddler. Since Batman has been ongoing since the 30s, we don't really see the endgame. But since Blaine is only one adversary in The Dark Tower, and not the endgame of their tale, we get to see who really defeats this opponent.
Thanks for playing along.