Computers inch ever closer to behaving like intelligent human beings—witness the ability of IBM’s Watson to beat the all-time champs of the television quiz show Jeopardy. So far, though, most people would doubt that computers truly “see” a visual scene full of shapes and colors in front of their cameras, that they truly “hear” a question through their microphones, that they feel anything—experience consciousness—the way humans do, despite computers’ remarkable ability to crunch data at superhuman speed.
How would we know if a machine had taken on this seemingly ineffable quality of conscious awareness? Our strategy relies on the knowledge that only a conscious machine can demonstrate a subjective understanding of whether a scene depicted in some ordinary photograph is “right” or “wrong.” This ability to assemble a set of facts into a picture of reality that makes eminent sense—or know, say, that an elephant should not be perched on top of the Eiffel Tower—defines an essential property of the conscious mind. A roomful of IBM supercomputers, in contrast, still cannot fathom what makes sense in a scene.