Physics of the Impossible

by Michio Kaku

  PSYCHOKINESIS AND THE BRAIN

  If psychokinesis does not easily conform to the known forces of the universe, then how might it be harnessed in the future? One clue to this was revealed in the Star Trek episode entitled “Who Mourns for Adonais?” in which the crew of the Enterprise encounters a race of beings resembling Greek gods, with the ability to perform fantastic feats by simply thinking of them. At first it appears as if the crew has indeed met the gods from Olympus. Eventually, however, the crew realizes that these are not gods at all, but ordinary beings who can mentally control a central power station, which then carries out their wishes and performs these miraculous feats. By destroying their central power source, the crew of the Enterprise manages to break free of their power.

  Similarly, it is well within the laws of physics for a person in the future to be trained to mentally manipulate an electronic sensing device that would give him godlike powers. Radio-enhanced or computer-enhanced psychokinesis is a real possibility. For example, the EEG could be used as a primitive psychokinesis device. When people look at their own EEG brain patterns on a screen, eventually they learn how to crudely but consciously control the brain patterns that they see, by a process called “biofeedback.”

  Since there is no detailed blueprint of the brain to tell us which neuron controls which muscle, the patient would need to actively participate in learning how to control these new patterns via the computer.

  Eventually, individuals could, on demand, produce certain types of wave patterns on the screen. The image from the screen could be sent to a computer programmed to recognize these specific wave patterns, and then execute a precise command, such as turning on a power switch or activating a motor. In other words, a person could, by simply thinking, create a specific brain pattern on the EEG screen and trigger a computer or motor.

  In this way, for example, a totally paralyzed person could control his or her wheelchair simply by the force of his or her thoughts. Or, if a person could produce twenty-six recognizable patterns on the screen, he might be able to type by simply thinking. Of course, this would still be a crude method of transmitting one’s thoughts. It takes a considerable amount of time to train people to manipulate their own brain waves via biofeedback.

  “Typing by thinking” has come closer to reality with the work of Niels Birbaumer of the University of Tübingen in Germany. He has used biofeedback to help people who have been partially paralyzed due to nerve damage. By training them to vary their brain waves, he has been able to teach them to type simple sentences on a computer screen.

  Monkeys have had electrodes implanted into their brains and have been taught, by biofeedback, to control some of their thoughts. These monkeys were then able to control a robot arm via the Internet by pure thought alone.

  A more precise set of experiments was performed at Emory University in Atlanta, where a glass bead was embedded directly into the brain of a stroke victim who was paralyzed. The glass bead was connected to a wire that in turn was connected to a PC. By thinking certain thoughts, the stroke victim was able to send signals down the wire and move the cursor on a PC screen. With practice, using biofeedback, the stroke victim was able to consciously control the movement of the cursor. In principle, the cursor on the screen could be used to write down thoughts, activate machines, drive virtual cars, play video games, and so on.

  John Donoghue, a neuroscientist at Brown University, has made perhaps the most significant breakthroughs in the mind-machine interface. He has devised an apparatus called BrainGate that enables a paralyzed person to perform a remarkable series of physical activities using only the power of his mind. Donoghue has tested the device on four patients. Two of them suffered from spinal cord injury, a third had a stroke, and a fourth was paralyzed with ALS (amyotrophic lateral sclerosis, or Lou Gehrig’s disease, the same disease that afflicts cosmologist Stephen Hawking).

  One of Donoghue’s patients, twenty-five-year-old Mathew Nagle, a quadriplegic permanently paralyzed from the neck down, took only a day to learn entirely new computerized skills. He can now change the channels on his TV, adjust the volume, open and close a prosthetic hand, draw a crude circle, move a computer cursor, play a video game, and even read e-mail. He created quite a media sensation in the scientific community when he appeared on the cover of Nature magazine in the summer of 2006.

  The heart of Donoghue’s BrainGate is a tiny silicon chip, just 4 millimeters wide, that contains one hundred tiny electrodes. The chip is placed directly on top of the part of the brain where motor activity is coordinated. The chip penetrates halfway into the brain’s cortex, which is about 2 millimeters thick. Gold wires carry the signals from the silicon chip to an amplifier about the size of a cigar box. The signals are then sent into a computer about the size of a dishwasher. Signals are processed by special computer software, which can recognize some of the patterns created by the brain and translate them into mechanical motions.

  In the previous experiments with patients reading their own EEG waves, the process of using biofeedback was slow and tedious. But with a computer assisting a patient to identify specific thought patterns, the training process is cut down considerably. In his first training session Nagle was told to visualize moving his arm and hand to the right and to the left, flexing his wrist, and then opening and closing his fist. Donoghue was elated when he could actually see different neurons firing when Nagle imagined moving his arms and fingers. “To me, it was just incredible because you could see brain cells changing their activity. Then I knew that everything could go forward, that the technology would actually work,” he recalled.

  (Donoghue has a personal reason for his passion for this exotic form of mind-machine interface. As a child, he was confined to a wheelchair because of a painful degenerative disease, so he felt firsthand the helplessness of losing his mobility.)

  Donoghue has ambitious plans to make BrainGate an essential tool for the medical profession. With advances in computer technology, his apparatus, now the size of a dishwasher, may eventually become portable, perhaps even wearable on one’s clothes. And the clumsy wires may be dispensed with if the chip can be made wireless, so the implant can seamlessly communicate to the outside world.

  It is only a matter of time before other parts of the brain can be activated in this way. Scientists have already mapped out the surface of the top of the brain. (If one graphically draws illustrations of our hands, legs, head, and back onto the top of our head, representing where these neurons are connected in general, we find something called the “homunculus,” or little man. The image of our body parts, written over our brain, resembles a distorted man, with elongated fingers, face, and tongue, and shrunken trunk and back.)

  It should be possible to place silicon chips at different parts of the surface of the brain so that different organs and appendages can be activated by the power of pure thought. In this fashion, any physical activity that can be performed by the human body can be duplicated via this method. In the future one could imagine a paralyzed person living in a special psychokinetically designed home, able to control the air-conditioning, TV, and all the electrical appliances by the power of sheer thought.

  In time one could envision a person’s body encased in a special “exoskeleton,” allowing a paralyzed person total freedom of mobility. Such an exoskeleton could, in principle, even give someone powers beyond those of a normal person, making him into a bionic being who can control the enormous mechanical power of his superlimbs by thought alone.

  So the problem of controlling a computer via one’s mind is no longer impossible. But does that mean that we might one day be able to move objects, to levitate them and manipulate them in midair by pure thought?

  One possibility would be to coat our walls with a room-temperature superconductor, assuming that such a device could be created one day. Then if we were to place tiny electromagnets inside of our household objects, we could make them levitate off the floor via the Meissner effect, as we saw in Chapter 1. If these electromagn
ets were controlled by a computer, and this computer were wired to our brain, then we could make objects float at will. By thinking certain thoughts, we could activate the computer, which would then switch on the various electromagnets, causing them to levitate. To an outside observer, it would appear to be magic—the ability to move and levitate objects at will.

  NANOBOTS

  What about the power not just to move objects, but to transform them, to turn one object into another, as if by magic? Magicians accomplish this by clever sleight of hand. But is such power consistent with the laws of physics?

  One of the goals of nanotechnology, as we mentioned earlier, is to be able to use atoms to build tiny machines that can function as levers, gears, ball bearings, and pulleys. With these nanomachines, the dream of many physicists is to be able to rearrange the molecules within an object, atom for atom, until one object turns into another. This is the basis of the “replicator” found in science fiction that allows one to fabricate any object one wants, simply by asking for it. In principle, a replicator might be able to eliminate poverty and change the nature of society itself. If one can fabricate any object simply by asking for it, then the whole concept of scarcity, value, and hierarchy within human society is turned upside down.

  (One of my favorite episodes of Star Trek: The Next Generation involves a replicator. An ancient space capsule from the twentieth century is found drifting in outer space, and it contains the frozen bodies of people who suffered from fatal illnesses. These bodies are quickly thawed out and cured with advanced medicine. One businessman realizes that his investments must be huge after so many centuries. He immediately asks the crew of the Enterprise about his investments and his money. The crew members are puzzled. Money? Investments? In the future, there is no money, they point out. If you want something, you just ask.)

  As astounding as a replicator might be, nature has already created one. The “proof of principle” already exists. Nature can take raw materials, such as meat and vegetables, and fabricate a human being in nine months. The miracle of life is nothing but a large nanofactory capable, at the atomic level, of converting one form of matter (e.g., food) into living tissue (a baby).

  In order to create a nanofactory, one needs three ingredients: building materials, tools that can cut and join these materials, and a blueprint to guide the use of the tools and materials. In nature the building materials are thousands of amino acids and proteins out of which flesh and blood are created. The cutting and joining tools—like hammers and saws—that are necessary to shape these proteins into new forms of life are the ribosomes. They are designed to cut and rejoin proteins at specific points in order to create new types of proteins. And the blueprint is given by the DNA molecule, which encodes the secret of life in a precise sequence of nucleic acids. These three ingredients, in turn, are combined into a cell, which has the remarkable ability to create copies of itself, that is, self-replication. This feat is accomplished because the DNA molecule is shaped like a double helix. When it is time to reproduce, the DNA molecule unwinds into two separate helixes. Each separate strand then creates copies of itself by grabbing onto organic molecules to re-create the missing helix.

  So far physicists have had only modest success in their efforts to mimic these features found in nature. But the key to success, scientists believe, is to create hordes of self-replicating “nanobots,” which are programmable atomic machines designed to rearrange the atoms within an object.

  In principle, if one had trillions of nanobots they could converge on an object and cut and paste its atoms until they transformed one object into another. Because they would be self-replicating, only a small handful of them would be necessary to start the process. They would also have to be programmable, so that they could follow a given blueprint.

  Formidable hurdles must be overcome before one could construct a fleet of nanobots. First, self-replicating robots are extremely difficult to build, even on a macroscopic level. (Even creating simple atomic tools, such as atomic ball bearings and gears, is beyond today’s technology.) If one is given a PC and a tableful of spare electronic parts, it would be quite difficult to build a machine that would have the capability of making a copy of itself. So if a self-replicating machine is difficult to build on a tabletop, building one on the atomic scale would be even more difficult.

  Second, it’s not clear how one would program such an army of nanobots from the outside. Some have suggested sending in radio signals to activate each nanobot. Perhaps laser beams containing instructions could be fired at the nanobots. But this would mean a separate set of instructions for each nanobot, of which there could be trillions.

  Third, it’s not clear how the nanobot would be able to cut, rearrange, and paste atoms into the proper order. Remember that it has taken nature three and a half billion years to solve this problem, and solving it in a few decades would be quite difficult.

  One physicist who takes the idea of a replicator or “personal fabricator” seriously is Neil Gershenfeld of MIT. He even teaches a class at MIT called “How to Make (Almost) Anything,” one of the most popular classes at the university. Gershenfeld directs the MIT Center for Bits and Atoms and has given serious thought to the physics behind a personal fabricator, which he considers to be the “next big thing.” He has even written a book, FAB: The Coming Revolution on Your Desktop—From Personal Computers to Personal Fabrication, detailing his thoughts on personal fabrication. The goal, he believes, is to “make one machine that can make any machine.” To spread his ideas he has already set up a network of laboratories around the world, mainly in third world countries where personal fabrication would have the maximum impact.

  Initially, he envisions an all-purpose fabricator, small enough to place on your desk, which would use the latest developments in lasers and microminiaturization with the ability to cut, weld, and shape any object that can be visualized on a PC. The poor in a third world country, for example, could ask for certain tools and machines they need on their farms. This information would be fed into a PC, which would access a vast library of blueprints and technical information from the Internet. Computer software would then match existing blueprints with the needs of the individuals, process the information, and then e-mail it back to them. Then their personal fabricator would use its lasers and miniature cutting tools to make the object they desire on a tabletop.

  This all-purpose personal factory is just the first step. Eventually, Gershenfeld wants to take his idea to the molecular level, so a person might be able to literally fabricate any object that can be visualized by the human mind. Progress in this direction, however, is slow because of the difficulty in manipulating individual atoms.

  One pioneer working in this direction is Aristides Requicha of the University of Southern California. His specialty is “molecular robotics” and his goal is nothing less than creating a fleet of nanorobots that can manipulate atoms at will. He writes that there are two approaches. The first is the “top-down” approach, in which engineers would use the etching technology of the semiconductor industry to create tiny circuits that could serve as the brains of the nanorobots. With this technology, one could create tiny robots whose components would be 30 nm in size using “nanolithography,” which is a fast-moving field.

  But there is also the “bottom-up” approach, in which engineers would try to create tiny robots one atom at a time. The main tool for this would be the scanning probe microscope (SPM), which uses the same technology as the scanning tunneling microscope, to identify and move individual atoms around. For example, scientists have become quite skilled at moving xenon atoms on platinum or nickel surfaces. But, he admits, “it still takes the best groups in the world some 10 hours to assemble a structure with almost 50 atoms.” Moving single atoms around by hand is slow, tedious work. What is needed, he asserts, is a new type of machine that can perform higher-level functions, one that can automatically move hundreds of atoms at a time in a desired fashion. Unfortunately, such a machine does not yet exist. N
ot surprisingly, the bottom-up approach is still in its infancy.

  So psychokinesis, although impossible by today’s standards, may become possible in the future as we come to understand more about accessing the thoughts of our brain via EEG, MRI, and other methods. Within this century it might be possible to use a thought-driven apparatus to manipulate room-temperature superconductors and perform feats that would be indistinguishable from magic. And by the next century it might be possible to rearrange the molecules in a macroscopic object. This makes psychokinesis a Class I impossibility.

  The key to this technology, some scientists claim, is to create nanobots with artificial intelligence. But before we can create tiny molecular-sized robots, there is a more elementary question: can robots exist at all?

  7: ROBOTS

  Someday in the next thirty years, very quietly one day we will cease to be the brightest things on Earth.

  —JAMES MCALEAR

  In I, Robot, the movie based on the tales of Isaac Asimov, the most advanced robotic system ever built is activated in the year 2035. It’s called VIKI (Virtual Interactive Kinetic Intelligence), and it has been designed to flawlessly run the operations of a large metropolis. Everything from the subway system and the electricity grid to thousands of household robots is controlled by VIKI. Its central command is ironclad: to serve humanity.