(Yet another one of those posts.)
The opening credit sequence in Fight Club is a nifty little reverse-literalization of a common directorial device for representing thought on screen. The technique typically works in the manner it does at the end of the film's first scene. Start with a medium close-up of a face:
Note that the narrator indicates that he's had a revelation. The camera supports his claim by zooming into a close-up:
Then into an extreme close-up:
By zooming in on his face, David Fincher indicates that the audience is about to enter his mind. It's as if the camera's going to continue through his eyes and into his memory, which is why—as is the case here—such zooms are so often followed by a flashback:
Call it an abuse of frontality—that feature of a frame that allows the audience to drink deeply of a character's eyes and acquire sympathy with or knowledge of what lies behind them—but it's really just an arbitrary convention. There's no logical reason zooming in on a face should signal the beginning of a flashback. But it frequently does. What's interesting about the opening title sequence of Fight Club is that it reverses the convention. Via CGI, the audience sees an idea—represented by an electric flash of blue light—form:
The idea then travels around the brain:
Until it punctures the skin on Edward Norton's forehead:
And travels down the barrel of the gun Brad Pitt's holding in Norton's mouth before stopping at the sights:
At which point Fincher racks the focus and provides the audience with an extreme close-up of Norton's face:
Instead of zooming into an extreme close-up to flash back to a memory, Fincher opens the film by following a thought from its origin to an extreme close-up. Meaning that the title sequence and first scene work in tandem—thought-goes-out-to-camera and thought-goes-in-from-camera—to bookend that opening scene.
Is this in any way significant or just Fincher being fancy to be fancy? Considering that the tandem of the opening sequence and the first scene structurely suggests that this is all in Edward Norton's head, I'm tempted to argue the former. That said, the signal that weaves through the opening credits is an untranslated thought: it can be any neuronal transmission relevant to Norton's current predicament. The audience can only infer its content from its timing, which means it could be, to name but two examples, Norton's decision to stick the gun in his mouth or the fear of what he'll do with it once there. In short, Fincher's credit sequence undermines the logic of the very convention he employs to transition from the first scene to the flashback.