I sat down and watched this movie again with an eye towards reading this movie as an attempt to demystify the "buddy cop" movie, because as I watched I was struck at how unlike so many cooperative detective films it is.
In the same way that Unforgiven effectively destroys the ideal Westerns of the past, Se7en (although an inferior film to Eastwood's classic) may be a nail in the coffin of the Lethal Weapons of the world. Let me be clear: David Fincher did not sit down and aim his film at a genre that his movie could not even be coded as. The intent of Se7en and Lethal Weapon or 48 Hrs. could not be more different, but this movie makes those other "buddy cop" movies seems piddling and trifling.
Brad Pitt's David Mills comes off to me as something of a meathead. The term is rather pejorative but it conveys exactly what I mean. He wants justice. He transfers into the Queens district homicide unit because he wants to catch bad people doing bad things. His character's focus on work and rightness can be encapsulated by his decision to move to a tougher more raw district- the move worsened his home life and wife's disposition substantially.
Morgan Freeman's Somerset is the streetwise, seen-it-all, world weary cop. He's a week from retirement. When they discover the first body he recognizes the work of a serial killer and wants no part of it. He is almost done with his tour of duty in the black depths of civilization, and would just as soon get out.
In investigating the first murder the dynamic between the two partners is clear: Somerset knows what is up, and Mills is a young hothead. Mills makes all sorts of typical Law and Order style wisecracks when they discover the obese corpse of John Doe's first victim. Somerset's glares of derision say it all- wiseacre dark humor doesn't have any part of this business.
That Mills is out of his element is made clear very quickly in the movie. He does not know how to proceed when a second body turns up and Somerset is off the case. He requires the help of Somerset to move to great works of literature to help to understand the relationship of the seven deadly sins to the killer and the crime.
The movie is slow for long stretches. This is because witing is integral to detectivework, according to Somerset. Mills hates the waiting. He wants to go do something. The brash, hotheaded youngster wants to go "kick some ass". When he finally gets a chance to hotdog it, his life is spared through only the (well its not mercy) choice of the killer. Not only is he not a great detective, he's not the most accomplished in a physically demanding footchase. If only the young hothead was played by Mel Gibson, THEN he would've gotten the killer.
The narrative of the film gives almost all the skill and talent to the experienced Somerset. The only exception is when Somerset refuses to go into Doe's house without a warrant- Mills resolves that problem quickly (but in a corrupt way, and police corruption comes full circle in the end of the film). The upshot, though, is that the young Mills gets more than his comeuppance for his wisecracks and hot headed behavior.
What a great film. Watch often.