What do you think is Brinker's motivation for imagining himself, as Gene puts it, "Justice incarnate"?

Brinker's extended joke about Gene's guilt was a bit odd, and his obsession with Finny's accident and condition is unexplainable. Brinker has absolutely no reason to suspect any foul play, since he wasn't at school when it happened, and none of the boys present said anything of the sort to anyone. It seems like a form of ESP for Brinker to just waltz in on he first day and automatically know what happened outside of his presence; and why he would be completely obsessed with events which had nothing to do with him, and for which he was not present, is even more mysterious. Brinker is obviously meant to be a kind of conscience figure, intended to dredge the ugly truth up in front of Gene and Finny; but isn't this purpose rather redundant, since both Gene and Finny know the truth without Brinker's unwanted interference?

To state it plainly, Brinker has no stake in the matter, and no motive in his actions that is discernible from the text. He has no way of knowing what went on, and no sources to draw on in order to create his "theories." The patchy motivations and the indistinct characterization of Brinker make him seem like another symbolic figure. It is as if he were a creation of both Gene and Finny's inner conscience, reluctantly spawned by both of them as a way of forcing themselves to confront the realities of the accident, and their state afterward. Brinker is another character who is anything but realistic, and operates on a more allegorical and less realistic plane than a character like Gene. The novel itself seems to be attempting some sort of realism, with its carefully drawn main characters, its painstakingly constructed settings, and its extensive treatment of themes relating to ordinary human nature. But, in places like this one, the story loses its realistic thread and tries to vault itself to the level of a parable. The novel is uneven because of this divide between two different genres and kinds of writing; it is an incomplete work of realism colored with self-examination, combined with an incomplete parable.

The inquiry itself is rather odd, since neither Gene nor Finny consent to it or want to take place in the proceedings. Brinker resides as the chief of the proceedings, hell-bent on getting the "facts" into the open for everyone's own good; how ironic, since it is the disclosure of the facts which causes Finny's second accident, and puts a great traumatic strain on him and Gene. As Gene says in his apt metaphor, Brinker is "imagining himself Justice incarnate"; but even Gene knows that Brinker is going at this from the wrong angle, since "Justice incarnate is also blindfolded," while Brinker is trying to get his desired outcome out of the whole affair (161).