The utilization of flashback in film noir is one of the genre's most crucial devices. Given the main action has already taken place and shape. It is too late to change anything, forget that eleventh hour. Fate has now taken its course and often the films like the quintessentially titled Out Of the Past, a pastoral masterpiece directed by Jacques Tourneur in 1947, traces their own histories like a curse that works itself out.
In 1944's Double Indemnity for example, Fred MacMurray is in quite the pickle - bleeding to death and starts to talk about what has happened right before he perishes. There is no question that anything will be changing. The trap was sprang before the film had even commenced. The device of the flashback or the so-called 'confessional' narration involves extensive ironies : the facts of the narration and the more objective images of the flashback scenes, let us say, they don't always add up to : kosher. When we listen to Fred MacMurray intimating to us, his fateful encounter with Barbara Stanwyck, he appears to be exacting much of the moral blame onto her, but the images we are offered in the flashback scene are far more ambiguous, the guilt is not easily attributable to one person.