What does Darl's eye symbolize in As I Lay Dying?

Darl's eye is a symbol of the light of truth. He sees people for who they truly are, and he understands their true motivations. This is why Tull says, ""He is looking at me. He don't say nothing; just looks at me with them queer eyes of hisn that makes folks talk. I always say it ain't never been what he done so much or said or anything so much as how he looks at you. It's like he had got into the inside of you, someway. Like somehow you was looking at yourself and your doings outen his eyes."