How we cite our quotes: All quotations are from North by Northwest.
Quote #4
VANDAMM: When you return to New York, do say goodbye to my sister for me, and thank her for her superb performance as Mrs. Townsend.
Notice that Vandamm uses the same language to praise his sister that Thornhill had used to condemn "Mrs. Townsend" as a liar. These two guys really can't agree on anything in the film except this woman's performance. And it's telling that this is the thing they'd agree on, since both men rely on performance as the film unfolds.
Quote #5
VANDAMM (to Thornhill): Has anyone ever told you that you overplay your various roles rather severely, Mr. Kaplan?
The irony here is that Thornhill isn't yet acting; he's telling the truth, that he's Thornhill, not Kaplan. But in the world of North by Northwest, truth and lies are hard to tell apart. In the spy biz, everyone's lying and assumes the other guy is too. Eventually, Thornhill will have to play Kaplan—and "play dead" as Vandamm predicts—in order to rescue Eve.
Quote #6
THE PROFESSOR: We created George Kaplan.
The Prof points to the fact that fictions can acquire lives of their own. It's as if spy agents were artists: the fictional Kaplan becomes the real Thornhill, who becomes Kaplan, in order to become fully himself (i.e., his own man, no longer his mother's son, and so on). It's a beautiful narrative system that doesn't get completely sorted out until the last impostor—Eve—is revealed to be working for the feds. Whew!