Faulkner uses dramatic irony and perspective shifts as a motif in the novel, often circling back to the same event from multiple characters' perspectives. For example, in Chapter 13, the boy who drove Christmas away from Joanna's burning house recounts his own version of events:
The boy believed that he was about to be robbed and even killed, and he told how he was about to trick the man into permitting him to drive right up into his own front yard, where he intended to stop the car and spring out and shout for help, but that the man suspected something and forced him to stop the car and let him out.
The reader has already heard this story from Christmas's perspective. Christmas waved down the passing car and asked for a ride. The boy and girl in the front seat started acting strange and refusing to stop the car, so Christmas bailed out. Only afterwards did he realize he had been brandishing a gun. He did not mean to threaten the young couple at all; he only wanted a ride and was too distraught to realize how he came off.
The boy truly seems to believe that his life was in danger. It is hard to blame him for this fear, given that Christmas had a gun and was clearly agitated. The boy is not lying in the slightest. Still, the sheriff and townspeople absorb his subjective version of the truth as the objective truth. The reader, who knows another subjective truth, can see that objective events are being accidentally distorted.
As a modernist writer, Faulkner was interested in how he could experiment with storytelling to best represent life in rural Mississippi. The retelling of the same moments from different perspectives helps him offer his readers a more complete sense of all his characters' reality than is possible with a single telling. At the same time, there is a chasm between what he can offer his readers and what the characters are able to experience. One of the tragedies of the novel is that while the reader can see how and why events play out the way they do, most of the characters are caught in their own distorted versions of the truth. They are thus doomed to misunderstand one another and descend into unnecessary conflict.
In Chapter 15, a group of men in Mottstown brings Mr. Hines home after he recognizes Joe Christmas and calls for him to be lynched. The scene ends on a note of dramatic irony and foreshadowing when Mrs. Hines asks her husband about "Milly's baby":
Eupheus. You listen to me. You got to listen to me. I aint worried you before. In thirty years I aint worried you. But now I am going to. I am going to know and you got to tell me. What did you do with Milly’s baby?
True to the Gothic genre, Light in August features an orphan, Joe Christmas. Questions have swirled around Christmas's racial heritage his entire life. On the one hand, whether or not he is Black changes nothing about the actual events of the novel. On the other hand, much of Christmas's behavior is driven by the belief, by him and others, that he is Black and that his Blackness makes him violent. When Mrs. Hines asks Mr. Hines, "What did you do with Milly's baby?" the reader finally gets a partial clue as to who Christmas's parents are. Mrs. Hines is clearly also learning information she has been missing for 30 years, since Christmas was a baby.
Faulkner immediately cuts to a different scene, refusing to reveal everything right at this moment. The cliffhanger of a question not only amplifies the dramatic irony and suspense, but it also foreshadows the revelatory scene that usually takes place near the end of a Gothic novel. Soon, several of the characters will confess to one another all the information they have secretly been holding onto for years. By playing with the conventions of the literary genre he is using, Faulkner further highlights the fact that all of his characters are caught in a fictional story. They are all subject to tropes and patterns that were established long before they came along. Far from trivializing the novel as a representation of Southern culture, Faulkner's emphasis on its literariness helps the reader see how cultural stories direct the course of people's lives. Christmas's actual identity is in some senses less important than his and others' assumptions about who he is and what that means.