That McGuffin thing has gone meanwhile completely out of control. It was not much more than a little joke played against critics who blamed Hitchcock's thrillers for not having enough substance. It was a kind of offensive defence by saying "look, you did not even understand what the films are about, you criticised them for the most unimportant things". Truffaut formulated this even better when he wrote: "Hitchcock has long been judged by the flowers he places in the vase, but it was in fact the modelling of the vase which got all his attention".The MacGuffin was nothing more than an absurd story to describe that the story motivating background of some of Hitchcock's spy thrillers was unimportant and interchangeable. The story needed this plot device, without it there wouldn't be a story, but for the film's protagonist and for the film's audience it is rather unimportant what it really is. Cause Hitchcock was interested to have Robert Donat being on the run in the Scottish highlands handcuffed to a beautiful woman or Cary Grant being mistaken for a dangerous spy.But for being a MacGuffin it is important that this story device does not appear in the film itself, does not really become a part oft he film. Like The Guns of Navarone without the guns or Treasure Island without ever reaching the island.But meanwhile everything which motivates a film in the background seems to be a MacGuffin. Rosebud in Citzen Kane, the falcon statuette in The Maltese Falcon, the money bag in No Country for Old Men are no MagGs, but the Rabbit's Foot in MI III is one. If e.g. the stolen money at the beginning of Psycho is a MacG, then every film about money, gold, jewels, treasures etc has a MacG, but when every film has one it is nothing special, and then the whole MacG thing has turned itself into some kind of MacGuffin.
Like the whole noir thing - are there any crime films that are not noirs?
After several story credits for ALFRED HITCHCOCK PRESENTS, the director brought Coppel back for VERTIGO, where he was one of at least three writers to take a crack at the tricky PIERRE BOILEAU and THOMAS NARCEJAC novel; whatever his approach, his script was discarded, and a new writer, SAMUEL A. TAYLOR, was brought in to start from scratch.
He [Thornhill] is a man who figuratively isn't there--until he's confused with George Kaplan, a man who literally isn't there, a fictional construct who is (in actual truth) an empty suit, moved around from vacant room to vacant room. And the curious thing is that, by being confused with Kaplan, Thornhill, who isn't really present for anyone or anything in his life, suddenly becomes real and of vital importance. He is pursued by villains, he pursues a lovely woman, he takes action. He is alive, and he has an identity at last--and only because his own identity was MISTAKEN for someone else's and his own life was taken over by a man who never lived.