Why Mystery Stories Appeal

Harold...realized that he'd never before had to put into words his reasons for loving the Holmes stories.

"I think I love the idea that problems have solutions. I think that's the appeal of mystery stories, whether their Holmes of someone else. In those storiezs we live in a understandable world. We live in a place where every problem has a solution, and if we were only smart enough, we could figure them out..."
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"As opposed to...?"

"As opposed to a world that's random. Where violence and death are happenstance--unpreventable and unstoppable. Of all the conventions of mystery stories, the one that impossible to break is the solution at the end. Conan Doyle has writings in his journals about it. And plenty of novelists since have tried.

"Can you write a mystery story that ends with uncertainty? Where you never know who really did it? You can, but it's unsatisfying. It's unpleasant for the reader.
There needs to be something at the end. It's not that the killer even needs to be caught or locked up. It's that the reader needs to know.

"Not knowing is the worst outcome for any mystery story, because we need to believe
that everything in the world is knowable. Justice is optional, but answers, at least, are mandatory. And that's what I love about Holmes. That the answers are so elegant and the world he lives in is so ordered and rational. It's beautiful."

From Chapter 34, pages 255-6, in The Sherlockian by Graham Moore (2010)