"But how does not believing in them help me?"

In Wolf Hall, Hilary Mantel uses a startlingly successful description that I recall her using before: she writes that Cromwell's adopted son Richard is "rinsed with relief" on learning that he won't be marrying into the Boleyn family. She had used a variation on that phrase before, in her memoir, Giving Up the Ghost (2003), describing herself as "rinsed with nausea" on seeing a devil, or some force of pure evil, in her backyard as a girl.

I've never encountered that construction in any other writer's work, but it has now become a permanent part of my mental makeup, for it describes the sensation so perfectly--that inescapably liquid release of chemicals that accompanies, and helps us interpret, sudden, overwhelming changes in the world before us. We can feel their very movement as they course through our bodies, a cocktail of complicated feelings and sensations in their wake.

"Rinsed with fear" would seem a particularly suitable way to imagine an encounter with a ghost: it is as if at the very moment when the sight before us should be calling into question all our assumptions about the inextricable link between the corporeal and the incorporeal self, the body--with its flood of adrenaline, its horripilations, its shivers, the whole mess of reactions that Dickens located in "an agreeable creeping up our back"--is forcing us to acknowledge that for now, at least, we are here in a physical body, and its processes are the movements of our minds and emotions, whatever contrary evidence that thing in the doorway may be offering.

Which is, ultimately, what's so scary about the idea of seeing a ghost: not what it may do, but merely that it is, and the challenge that offers to our daily rationality. Which brings me to Kafka, and a passage from his story "Unhappiness" that I found in D. J. Enright's Oxford Book of the Supernatural (1994):

"What can I do?" I said. "I've just had a ghost in my room."

"You say that with the same sort of distaste as if you'd found a hair in your soup."

"You jest. Mark my words, though: a ghost is a ghost."

"Very true. But what if one doesn't believe in ghosts in the first place?"

"You don't think I believe in ghosts, do you? But how does not believing in them help me?"

"Very simple. You no longer need be frightened when a ghost actually appears."

"Yes, but that's only the incidental fear. The actual fear is fear of what causes the phenomenon. And that fear there's no getting rid of."

And now to crawl under the covers and not emerge for any sound that's not clearly made by a cat. A living, familiar cat, that is.