Let's start with one of my favorite episodes from one of my favorite novels. Huck wanders ashore and witnesses the cold-blooded daylight murder of a drunk named Boggs. A lynching party gathers to get the murderer, Colonel Sherburn. Well, Sherburn faces down that mob, calls them cowards, calls all of mankind cowards, and off the mob goes, to their various houses, tails between their legs. And that's not all. In the next scene, Huck goes off and sees a CIRCUS! A circus, I mean, what the hey? After the chilling mordant scene with Sherburn, Twain can't think of anything better to do than to take us to a circus! Strange thing is, it works, but the even stranger thing is, neither one of these episodes, neither the one with Sherburn or the visit to the circus, has ANYTHING TO DO WITH THE STORY!
Jim's not in either one of them. You could take both sections out, without marring the story in the least. Now of course, part of this has to do with the fact that Huck Finn is a picaresque, so a lot of the episodes are kind of random anyway, but then what about that other great novel, Moby Dick. Take all of the inner chapters - the digressions if you will - the chapters on whiteness, on why it's impossible to draw a whale, about whether whales have faces, or how whales can see - take all of that out of Moby Dick, and what's left would be as short as, well, Huck Finn.
Again, none of that stuff directly affects the story, or even indirectly as far as I can tell.
I think every novelist has at least one (I have three) "learning novel" in a bottom drawer or an old flashdrive somewhere, a botched attempt at a novel, begun with all the enthusiasm and hope of youth and inspiration, and somewhere along the way becoming abortive, and finally being abandonned as the mishapen lump it is. I would venture to say that 99% of the time, what leads to the death of a learning novel is too damn many digressions. The novel forgets what it's about and starts chasing interesting butterflies, and next thing you know, you end up with a muddle that isn't one thing or another.
So how come Twain and Melville get away with digressions? More importantly, how can the rest of us? I've thought about this very carefully and here is my answer.
I don't know.
I think, however, it has something to do with how well the digression serves the overall structure, sometimes overtly and sometimes occultly, of the novel. Put more simply, a good digression seems to be a digression, seems to be leading away from the point of the novel, but actually is leading us into it. The crude master of this is Charlie Dickens. Stuff will appear in his novels that seems utterly out of place - a grave robbing scene? What's that doing there? Amusing, of course, but it hardly belongs in Tale of Two Cities, does it? Then twelve chapters, later, lo and behold, it does have to do with the plot, because it just so happens...
Dickens can't get along without his "just so happens" moments; I swear he should title at least one chapter in each of his novels, "It Just So Happens..."
Melville's and Twain's digressions don't pay off in the Dickensian sense - there's no revelation later of the significance of a seemingly irrelevant side-plot. But when Huck resolves to "light out for the territory" because he's had enough of being "sivilized" part of what's behind it is the chilling speech he heard from Sherburn. And when Ishmael is hanging onto Quequeg's coffin, awaiting rescue from the Rachel, we know we've have been on an odessy with him - not around the world, but around the whale - Moby Dick's subtitle is, remember, The Whale - and that's what it is - the novel itself is a whale, and like the levianthan can not be seen from all sides in one go, and so Melville needs his digressions just to give us the sense of scale.
Or something like that.
Anyway, what was my point? Oh, yes. A good digression isn't beside the point. It is the point.