Originally published 14 November 1994
I had been reading Roger Penrose’s new book on the science of human consciousness and wanted to discuss it with my wife.
“Not now,” she said, “I’m watching television.”
So I stretched out on the couch and tried to join in. The last thing I remember before drifting off to sleep was a commercial for a Black & Decker coffee maker: “The coffee maker that’s capable of intelligent thought at 7 a.m.”
I awoke at seven, still eager to discuss Penrose’s book. My wife was asleep upstairs. I made my way to the kitchen and engaged our coffee maker in conversation.
“What do you think of Roger Penrose’s contention that computers will never become conscious?” I asked.
“Who is Roger Penrose?” the coffee maker queried, with computerly attention.
“He is a professor of mathematics at Oxford University, a physicist who has worked with Stephen Hawking on the structure of the universe, a computer whiz, and about as close to an all-round genius as one could hope to find.”
“Is he the guy who wrote the popular book The Emperor’s New Mind a few years back?”
“Yeah, that’s him. The book spent some time on the New York Times bestseller list. Not bad for a rather technical work on computers, brains, and physics.”
“It seems there’s a lot of interest in the problem of consciousness,” said the coffee maker, “and especially in the question of whether computers might someday achieve human levels of self-awareness.”
“Indeed, there is,” I responded. “Almost every few months another book comes out by a famous scientist working on the problem of consciousness. For example, earlier this year Francis Crick, co- discoverer of the structure of DNA, published a book on the subject, called The Astonishing Hypothesis.
“What is his ‘astonishing hypothesis’?”
“That consciousness and self-awareness will someday be understood purely in neurobiological terms, without reference to mind-body dualism or quantum physics. In other words, the brain is a computer, with neurons firing away like silicon chips.”
“And Penrose, what does he think?”
“Precisely the opposite. That consciousness and self-awareness will forever elude computers. There is something about the way our minds work that is non-programmable.”
“Then does Penrose believe that science will never explain the mind?”
“No. Only that today’s physics is insufficient to explain consciousness. He looks forward to an explanation that evokes the mysteries of quantum physics…”
“Mysteries?”
“Well, not mysteries exactly. With computers, a data bit is either yes or no. In the quantum world, a single electron or photon can be yes and no, at the same time. Two places at once, in a manner of speaking.”
“Sounds like a violation of common sense.”
“You’re right. That’s why Penrose looks to quantum physics to explain those aspects of consciousness that would appear to violate purely computational sense. Intuition, for example. Or our sense of free will.”
“How does he get consciousness out of the quantum behavior of individual electrons or photons?”
“That’s the problem. Somehow these almost magical quantum effects would have to cohere across large areas of the brain. But large- scale quantum coherence, as we presently understand it, only occurs at extremely low temperatures, near absolute zero. The brain would seem to be too warm for this to happen.”
“You’re losing me. Remember it’s only seven in the morning.”
“Penrose thinks nature may have evolved a way to achieve what technologists have not yet accomplished and physicists have not yet explained.”
“You mean the brain is a quantum device that escapes the rigorously programmable restrictions of computers? Makes quantum leaps, so to speak? Insights? Flashes of genius?”
“Yeah, something like that.”
“But we don’t yet know enough physics to explain how it happens?”
“Right. According to Penrose, what’s missing is a theory connecting the quantum world of individual particles to the classical world of large-scale activity. Crick has a similar difficulty he calls the ‘binding problem,’ explaining how the firing of individual neurons can coalesce to form coherent thoughts and perceptions.”
“So, who is right, Penrose or Crick? Can computers become self- aware or not?”
“At this stage, these guys are whistling in the dark. We just don’t know enough about the physical basis of consciousness to say who is right. But this kind of speculation certainly suggests fruitful lines of inquiry, and helps inspire public interest that will support research.”
“Sounds like the next decade might be an exciting time for brain research. How about a cuppa coffee?”
“Good idea. I think I hear my wife stirring upstairs. It’s been fun talking.”
