A potential publisher, cordially refusing a novel synopsis of mine in the 1990s, told me, "Readers don't like unsolved mysteries. They prefer things to be wrapped up." I really don't agree.
Mysteries always seem to want to be solved, it's true. And in literature's case, traditionally, they are. But what of the mysteries that remain unresolved? Writers don't always choose to offer an explanation. We still don't know, for example, what happened to the picnic party of Australian schoolgirls that dis-appeared at Hanging Rock, as hauntingly in Joan Lindsay's 1967 novel as in Peter Weir's oneiric film of 1975. The enigma is left to hang like the Rock itself.
The mystery at the centre of A Pass-age to India (1924), meanwhile, may be unsolved for a different reason. By the end of the novel, we're none the wiser as to what did or didn't happen to Adela Quested in the Marabar Caves. Her claim that she was the victim of an attempted sexual assault generates a trial scene replete with inter-racial antagonism between the novel's Indian and British colonial characters.
But the trial collapses when Quested changes her story. From then on, she maintains that she doesn't know what happened in the dark of the cave. But in a footnote to his 2005 introduction to the Penguin Classics edition, Pankaj Mishra suggests that "what many people saw as the annoyingly unsolved central mystery… was neither central nor much of a mystery to Forster". It doesn't matter because it isn't the point. The novel is about the troubled social relations that obtained between a subject people and their imperial administrators, and the gathering political consciousness in the former that the trial helps to focus. A verdict either way would appear to settle a little local difficulty, and distract our attention from the larger historical forces at work.
The mother of all unsolved mysteries must be what Iago's motive is for the destruction of Othello and Desdemona. To Coleridge, famously, it's a piece of pure "motiveless malignity", and yet theoretical motives abound: envy at Oth-ello's social standing; sexual jealousy; racism; all of the above. The ingenuity of Shakespeare's only entirely domestic tragedy lies in the way the plotting allows its audience to entertain these theories, while at the same time being transfixed by the insidious psychological mechanisms of raging jealous breakdown.
A mystery is an effective narrative device. It maintains its hold on readers, whatever subplots grow twisting around it, all the way through to the closing stages, where we expect all to be revealed. When handled well, a lack of resolution, precisely by denying us the tidy ending of the story, has the advantage of leaving the reader continuing to think about it.