“Computers will never be people because they’re not indeterminate,” you said at last. “A computer uses switches that are either on or off. But the neurons in a brain, they excite, they light up in all kinds of different ways because they’re constantly getting information from other cells through synaptic contacts.” You smiled at the cashier and handed her a five-dollar bill and said, “Keep the change,” like a high roller.

As we walked back to the car you continued, “As long as we keep thinking of the brain as a computer we’ll never replicate consciousness. People like Markram can increase data transfer rates till they’re blue in the face, but that’s not consciousness. Brains don’t store and retrieve memories like computers. Brains don’t operate like binary systems, ones and zeros. But unfortunately computer metaphors for the brain are so entrenched that even neuroscientists find it hard not to use them. I’m serious, talk to a neuroscientist about the brain, I deal with them all the time at the university and they’re incapable of not using computer metaphors like encode and process when really these are describing computational functions.” You were starting to get a bit worked up. The car blinked at us as you pressed the remote key — even though I was driving you had insisted on carrying the key in your purse while we were in the store. “We apply whatever technological metaphor is most current,” you continued, opening the passenger-side door. “For thousands of years people believed the body worked like hydraulics, and science and medicine didn’t progress for millennia.” You climbed into your seat and then handed me the key. “A computer is like a really sophisticated filing system and it can sort numbers and images and videos and sound files at almost infinite speed, but I suspect it will never be able to truly understand what an image is, in a lived sense. The photograph of a loved one, say. What is that? Or understand that that sound file is a Chopin nocturne and be moved by it.”

You latched your seat belt. I turned the key in the ignition and began navigating my way out of the parking lot.

“There’s no…” you continued distractedly, pulling down the sun visor to check your eyes in the mirror for sleep. “What’s missing is the very complex biochemical dialogue between the mind and body that we really have no idea how to replicate.”

“But say if one day, like theoretically, we could reproduce that dialogue.”