What Is Consciousness?
In conscious thinking, you experience your thoughts. Often they are accompanied by emotions or by imagined or remembered images or other sensations. A machine with a conscious (simulated) mind can feel wonderful on the first fine day of spring and grow depressed as winter sets in. A machine that is capable only of unconscious intelligence “reads” its thoughts as if they were on cue cards. One card might say, “There’s a beautiful rose in front of you; it smells sweet.” If someone then asks this machine, “Seen any good roses lately?” it can answer, “Yes, there’s a fine specimen right in front of me.” But it has no sensation of beauty or color or fragrance. It has no experiences to back up the currency of its words. It has no inner mental life and therefore no “I,” no sense of self.
But if an artificial mind can perform intellectually just like a human, does consciousness matter? Is there any practical, perceptible advantage to simulating a conscious mind?
An unconscious entity feels nothing, by definition. Suppose we ask such an entity some questions, and its software returns correct answers.
“Ever felt friendship?” The machine says, “No.”
“Love?” “No.” “Hatred?” “No.” “Bliss?” “No.”
“Ever felt hungry or thirsty?” “Itchy, sweaty, tickled, excited, conscience stricken?”
“Ever mourned?” “Ever rejoiced?”
No, no, no, no.
In theory, a conscious software mind might answer “yes” to all these questions; it would be conscious in the same sense you are (although its access to experience might be very different, and strictly limited).
So what’s the difference between a conscious and an unconscious software intelligence? The potential human presence that might exist in the simulated conscious mind but could never exist in the unconscious one.
You could never communicate with an unconscious intelligence as you do with a human–or trust or rely on it. You would have no grounds for treating it as a being toward which you have moral duties rather than as a tool to be used as you like.
But would a simulated human presence have practical value? Try asking lonely people–and all the young, old, sick, hurt, and unhappy people who get far less attention than they need. A made-to-order human presence, even though artificial, might be a godsend.
AI (I believe) won’t ever produce one. But it can still lead the way to great advances in computing. An unconscious intelligence might be powerful. Alan Turing, the great English mathematician who founded AI, seemed to believe (sometimes) that consciousness was not central to thought, simulated or otherwise.
He discussed consciousness in the celebrated 1950 paper in which he proposed what is now called the “Turing test.” The test is meant to determine whether a computer is “intelligent,” or “can think”–terms Turing used interchangeably. If a human “interrogator” types questions, on any topic whatever, that are sent to a computer in a back room, and the computer sends back answers that are indistinguishable from a human being’s, then we have achieved AI, and our computer is “intelligent”: it “can think.”
Does artificial intelligence require (or imply the existence of) artificial consciousness? Turing was cagey on these questions. But he did write,
I do not wish to give the impression that I think there is no mystery about consciousness. There is, for instance, something of a paradox connected with any attempt to localise it. But I do not think these mysteries necessarily need to be solved before we can answer the question with which we are concerned in this paper.
That is, can we build intelligent (or thinking) computers, and how can we tell if we have succeeded? Turing seemed to assert that we can leave consciousness aside for the moment while we attack simulated thought.
But AI has grown more ambitious since then. Today, a substantial number of researchers believe one day we will build conscious software minds. This group includes such prominent thinkers as the inventor and computer scientist Ray Kurzweil. In the fall of 2006, Kurzweil and I argued the point at MIT, in a debate sponsored by the John Templeton Foundation. This piece builds, in part, on the case I made there.