The other night I glanced out the window and saw a large fire across the river as I passed. I took a step back and looked again.

There was no fire. What was there, across the river, was a small traffic jam at the end of a bridge. About a block away, thick steam was billowing from a building’s exhaust system.

Yet when I first glanced, for that split second, my brain saw what wasn’t there. My subconscious noticed the red-orange glow from the street and tail lights, and what could easily have been a cloud of smoke. And while they were neither, nor were they even together, my brain said “fire.”

It’s fascinating how we’ve evolved to see danger, even if it isn’t really there.