“Hold it there, Samuel! What’s the matter with your eyes?” he snaps without turning around. He carefully sticks down the last corner of the poster. His lower arms are powerful, and his fingers never shake.

“I . . . I have an allergy, sir.”

“Oh yeah? Well, so do I, Samuel: I’m allergic to liars.”

“I might have gotten some sand in them,” I answer tentatively, adding a reverent “sir,” just in case.

God turns to face me. He has one blue eye and one green. His right eye, the blue one, is cold, whereas the green one is warm—two different men staring out at me from the Viking face framed by strawberry-blond sideburns.

“Some sand, eh? You look as if you slept facedown on the beach. Trying to blind yourself? No? Ever heard of neuronavigation?”

“N-no, sir,” I stammer.

“Then come with me,” he purrs, and leads me up to the next floor and into the magnetic resonance imaging demonstration room.

“Allow me to present . . . the monster,” Dr. Saul says. “This is a functional MRI scanner. It measures brain activity. Bloody thing cost two million pounds and is regarded as England’s first mind reader. It’s so smart that we hardly understand how it works.” He points to a chair and says, “Sit down, tilt your head back, and open your eyes wide!” He trickles a few drops onto my eyeballs. This immediately relieves the stinging.

All at once it strikes me that God is very often very alone. Dr. Saul switches off the lights and turns on the projectors. The whole wall is suddenly plastered with images of slices of brain. My eyes feel better in the dark.

He runs his fingers slowly, almost lovingly, over the projections on the wall. “Here’s a splendid aneurysm. We plug it by entering through the upper thigh and working our way along the veins. Ooh, how about this one! A wonderful example of a hemangioblastoma, as snug as a pea in a pod.” His voice changes from black to light green to pink as he traces the outlines of different brains. God loves brains.

“Have you ever peered into someone’s soul, Samuel?” he says, beaming a microscopic view of the brain onto the wall. “These are the two halves of the brain, as seen from the spinal cord at the bottom of the neck. It’s as if you were climbing up a tunnel from the neck, striding down a long corridor to the end of the brain stem, and then stepping from the cerebellum into the center of the brain. The secret chamber, the seat of our humanity.”

He enlarges the picture until it takes up the entire wall. It looks like a cathedral, with veins for buttresses and cells like high vaulted ceilings. It’s magnificent—magnificent and very weird.

“A church built of thoughts,” I whisper.