Dennett, or Yorick, during a wakeful interval during the long time when Dennett, or Yorick, slumbered on without any thoroughgoing communication, direct or remote, with a living human body, mainlined a little Brahms. The rectified output from the stereo stylus was fed directly into the auditory nerves. A certain sort of scientist or philosopher would ask, “If we can bypass the middle and inner ear and feed directly into the auditory nerve, why can’t we bypass that as well and feed directly into whatever the auditory nerve feeds? Indeed, why not bypass that as well and feed directly into the subpersonal information-processing system another step farther in? Or into the next step beyond that?” Some theorists, but presumably not Dennett, would wonder when this process of replacing natural with artificial information-processing devices would reach the ultimate possessor of auditory experience, the real core person, the true seat of the soul. Others would see it rather as a layer-by-layer transformation, from the outside in, of an organic subject of consciousness to an artificial intelligence. The scientist shooting the Brahms piano trio straight into Yorick’s auditory nerves, however, actually asked himself a different kind of question. He wondered why they had bothered to disconnect Dennett’s ears from his auditory nerves. There would have been advantages, he thought, if we could have used earphones on the ears connected in the normal way to the brain in the vat and had microphones instead of organic ears on the body that ventured deep below Tulsa. The belief that the radiation could damage only brain tissue had been utterly mistaken. Indeed, the organic ears on Hamlet had been the first to go, and the rest of Hamlet was killed off shortly thereafter. With microphones instead of ears on Hamlet, and earphones on the ears connected normally to Yorick, Dennett could get a more realistic stereo rendition of a musical performance than could be obtained merely by mainlining the output from a stereo cartridge tracking a normal stereo recording. If Hamlet sat in the concert hall during a live performance, then every turn of the head would result in slightly different outputs from the earphones back in Houston. This set up would preserve the slight differences in volume and the slight time delay between the two signals that, although not consciously discernible, are so important in fixing the location of a sound source.
A description of this marginal improvement on earphones serves as an analogy in the explanation of some more radical advances made by the NASA technicians. Human eyes, they discovered from the Dennett caper, could not long withstand the fierce radiation from the buried warhead. It would have been better to leave Dennett’s eyes attached to his brain as well and mount little television cameras in Hamlet’s empty eye sockets. By the time I had entered into the secret mission to retrieve the warhead, the technicians had perfected eyevideos. Eyevideos are to seeing what earphones are to hearing. They not only project an image on the retina, they monitor every movement of the eyeball. For every rapid eye movement, there is a corresponding rapid camera movement; for every twist of the head, there is a corresponding shift in the cameras; and so on. Seeing by means of eyevideos is in most circumstances indistinguishable from seeing without them. When trying to read really fine print, I noticed a slight loss of acuity; and, until the system was finely tuned, my night vision was rather better with eyevideos than without.
The most amazing simulation devices were for tactile perception. But before I describe skintact, which is to cutaneous and subcutaneous feeling what earphones are to hearing, I should like to describe some experiments that can be performed with eyevideos. The classic experiment with inverting lenses can be repeated simply by mounting the cameras upside down. New experiments of the same general sort can be performed by mounting the cameras in other positions that diverge from the normal. Here are a few: the so-called rabbit mount, with the cameras facing in opposite directions instead of side by side; the rabbit mount with extreme wide angle lenses, so the field of vision is 360 degrees; and the so-called bank or supermarket mount, with the two cameras mounted on opposite walls of the room that the subject occupies. This one takes some getting used to. It is possible, by the way, with this setup to see all the sides of an opaque cube at the same time.
But you want to hear more about skintact. It is a light, porous material worn right next to the skin, and it extends one’s tactile range as radio and television extend one’s auditory and visual range. When an artificial hand equipped with skintact transmitters strokes a damp puppy, the nerves in the skin of a real hand enclosed in receptor skintact are stimulated in just the way they would be if the real hand that contains them were stroking a damp puppy. When the skintact transmitter touches something warm, the corresponding skin covered with the receptor skintact does not actually warm up, but the appropriate sensory nerves are stimulated as they would be if warmth were actually present.
In order to retrieve the buried warhead, a robot was sent underground. This robot contained no living cells. It had the same proportions as my body; it was covered with skintact transmitter; its head had microphones and cameras mounted in it that could transmit to earphones and eyevideos. It was jointed just as my body is jointed and could move in most of the ways my body moves. It did not have a mouth or jaws or any mechanism for inhaling and exhaling air or for ingesting food. In place of a mouth, it had a loudspeaker that put forth all the sounds picked up by the microphone in front of my mouth.
There was another marvelous intercommunication system between me and the robot, the Motion and Resistance System, or MARS for short. The MARS membrane is worn over the skintact layer covering the human subject and under the skintact layer worn by the robot. I don’t understand all the details of how MARS works, but it isn’t difficult to say what it does. It enables most of the bodily motions of the human to be duplicated exactly and simultaneously by the robot while the various pressures and resistances encountered by the limbs of the robot are duplicated for the corresponding human limbs.
The NASA scientists, instead of splitting me up, as they had split up Dennett, would leave me entire. I would stay back in Houston, all of me, and without suffering any effects from radiation would control a robot on its underground mission. The scientists assumed that, unlike Dennett, I would not be distracted from the primary purpose of the mission by abstruse philosophical questions about my location. Little did they know.
Dennett mentions laboratory workers who handle dangerous materials by operating feedback-controlled mechanical arms and hands. I was to be like them, only I would be operating a feedback-controlled entire body with prosthetic hearing, seeing, and feeling. Although it might be as if I were deep in the tunnel under Tulsa, I would know perfectly well where I really was, safe in the laboratory wearing earphones and eyevideos and skintact and MARS membrane, and speaking into a microphone.
It turned out, however, that once I was all rigged up, I could not resist the inclination to locate myself in the location of the robot. Just as Dennett wanted to see his brain, I wanted to see myself swathed in my electronic garments. And just as Dennett had difficulty identifying himself with his brain, I had difficulty identifying myself as the body that moved its head every time the robot moved its head and moved its legs in a walking motion as the robot walked around the laboratory.
Following Dennett’s example, I began naming things. I used “Sanford” as Dennett used “Dennett” so that the questions “Where was I?” and “Where was Sanford?” should receive the same answer. My first name, “David,” served as a name for the mostly saltwater and carbon compound body being cared for in Houston. My middle name, “Hawley,” served for a while as the name of the robot.