Jordan Paige at 2012-06-28 13:10:46:
I think the theme is very clearly death, but the message the Coen brothers delivered was far less grim than most would expect. The theme seems to be more indifferent than it is anything else.
Take Moss's death for example. He's the seeming protagonist. Then, suddenly he's dead a little more than half way through. We don't get to see him go out, guns blazing. He isn't even killed by the antagonist. His death just... happens.
Chigurh is unexpectedly t-boned in his car. He gets out of the crash, severely hurt and walks away. Even a death dealer is prone to his master. Chigurh got lucky, but he could have easily met misfortune.
The coin toss is the perfect example of the Coen brothers' approach to their theme. If it's your time, it's your time. Chigurh could have just killed him, but it doesn't work like that. Death comes for you when Death wants you.
GAS ATTENDANT
I didn't put nothin up.
CHIGURH
Yes, you did. You've been putting it up your whole life you just didn't know it.
Oddly, the most violent of the characters may have the greatest appreciation for life. Chigurh seems to be the Sage of the characters and the embodiment of the theme. While the other characters (and probably audiences) conceive him as violent, malevolent, what have you, it's because he runs on a moral code of his own. A moral code that differs because he views life far differently than any of the other characters. We see his view on life articulated in the coin toss scene.
I think the Coen brothers (or Cormac McCarthy) were illustrating how all the other characters simply have flawed views. This is also pointed out:
ELLIS
Whatcha got ain't nothin new. This country's hard on people, you can't stop what's coming, it ain't all waiting on you. That's vanity.