Movies such as The Matrix have popularized the idea that we may be living in a virtual reality. In The Matrix, people think they are  living in a modern city, but they are really bodies stored in vats, wired to a central computer that immerses them in a world of illusion. Although the story is wildly fictional, it may contain a core of truth. Military simulators routinely place soldiers on a virtual battlefield for training. Over the last few decades, computers have increased greatly in power according to Moore's law, and we can envision computers that will vastly exceed the complexity of the human brain and sensory system. Could we already be living in a virtual reality? If so, what is the "real" reality? Are we bodies in vats, or something else entirely?

In this book I explore the idea of virtual reality as a metaphor for our situation as conscious beings. This metaphor is a convenient framework for raising many questions about consciousness.

I begin by asking the old question about whether or not machines might be able to think. This question was posed by the British computer pioneer Alan Turing after he defined the modern concept of a universal computer. According to Turing, we can imagine how practically any human behavior can be defined according to rules. For example, my behavior of writing these sentences follows rules of grammar, and the logic of the points I am making also follows rules. Turing argued that such behavior can be produced by a computer and that, in the ultimate issue, there is no discernible difference between human mental functioning and its simulation by a suitably programmed computer. Computers, in principle, can think.

This idea is supported by modern physics. According to physics, everything in nature follows computable rules given by equations. (Even random events can be dealt with by computing probabilities.) This must be true of the brain, which seems to be the physical source of all human thinking. Therefore, thinking follows the laws of physics.

Since a computer can, in principle, calculate anything that happens according to these laws, computers can think.
This reasoning seems persuasive, but questions remain. Although nature may follow physical laws, few think that calculations following these laws duplicate nature. They merely simulate nature. So does Tur-ing's proposed thinking computer actually think, or does it just simulate thinking? Philosophers from Leibnitz to John Searle have argued that the essence of consciousness is left out of any mechanical simulation of thought, no matter how accurate it might be. Consciousness seems to be a mysterious element that makes us aware of what we are thinking. Without it, thoughts might still unfold according to rules, but there would be no awareness of them.

But other philosophers, such as Daniel Dennett, point out that since everything we are aware of is rule based, there is no reason to postulate some mysterious missing element we cannot see or explain.

Rene Descartes had proposed a division between matter, which follows physical laws, and a hypothetical thinking substance, which is self-aware and endowed with free will. This division calls for an interaction between the nonphysical mind and matter. Material sense data is impressed on the mind, and mental will is impressed on matter. How-ever, the laws of physics say nothing about this mind-body interaction, and to many philosophers this decisively rules out Descartes' theory.

It is here that virtual reality comes into the picture. A virtual reality is a computer-generated world that a human observer can perceive and influence by willful action. Since visual perception is so important for humans, virtual realities began to take practical form with the develop-ment of realistic computer graphics, starting with computerized flight simulators for military pilots.

Computer graphics is based on simulations following the laws of physics. For example, consider a computer animation of water pouring out of a  glass and splashing on a table. To make this look realistic, it is necessary to simulate the behavior of water by solving the equations of fluid flow. Very realistic looking effects can be produced in this way, and it is clear that the way of the future in computer graphics is to make better and better physical simulations.

However, the simulations don't have to be perfect to be convincnig. In practice, one can program the computer so that a human being can direct action that is being physically simulated without seriously violating physical laws. Today's computer games do this crudely, but we can see that as computers become more powerful, the realism of interactive simulations will progressively increase. In the world of computer simulation, Descartes' idea turns out to be realizable. One can consciously control effects that look real, and there is no practical limit on how real this can be.

To enter into a virtual reality, there has to be an interface between the human participant and the computer-generated world. Ideally, the human should receive all his or her sense data from the computer, and willed actions should be intercepted by the computer and used to control a virtual body.     

This is where things get messy. Scientists postulate that consciousness dwells in the brain. So a live brain linked to a powerful computer can consciously experience life in a virtual world generated by the computer. We have arrived at the bodies in vats portrayed in The Matrix. We have a kind of reversed Cartesian dualism of matter and virtual matter. Matter in the wired brains experiences an illusory reality produced by virtual matter in the computer.

But what if we already live in a virtual reality? In that case, this world is an illusion created by "something else," and perhaps our consciousness also comes from something else. We don't know what that something else is, but we can simply call it Ground Reality. I will explore the hypothesis that the world is an illusory construct of a Ground Reality that includes our consciousness. Computer generated virtual reality provides a metaphor that helps us think about this hypothesis.

We must first ask how far one can really go in making a virtual reality both controllable and in agreement with the laws of physics. To answer this, I survey relevant topics in modern physics in Chapters 2, 3, and 4.

In Chapter 2,1 discuss the idea that determinism in physics rules out free will. Historically, this notion gave rise to the deistic idea that God is a clockmaker who built the universal clock, set it in motion, and left it alone from then on. But it turns out that the modern idea of deterministic chaos allows one to have both physical determinism and free will. Chaotic systems can be guided in desired directions by introducing immeasurably small deviations in the course of events.

Chaotic systems are quite common in nature. For example, they are found in weather and in the brains of living organisms. Control through guided chaos is possible in a virtual reality system that mimics the deterministic laws of physics. If we already live in a virtual reality, then it is possible that free will does play a role in our world, even in areas where deterministic physical causation seems to be the rule.

However, there are drawbacks to this scheme. First of all, the second law of thermodynamics seems to say that disorder in a physical system should increase. This appears to contradict the idea that chaos could be guided to introduce order. Indeed, if we look at the theoretical basis of the second law, we find that it deliberately blurs the fine detail of nature, making it "coarse grained." In effect, physicists are postulating small random changes that produce disorder. The solution is to make random changes on the whole, as required by the second law, but also make planned changes which introduce order as needed.

Time also poses a problem. In a man-made virtual reality, the brains of the human subjects follow their own biological time, and the simulated world has to follow this standard of "real time." However, it is not clear why consciousness itself should be limited by a particular standard of time, and we can postulate that time in our Ground Reality is determined not by consciousness but by the relative circumstances in which consciousness manifests. This, of course, is also the view of mystical traditions.

Curiously, we are forced to such an assumption by Einstein's theory of relativity. For example, in the twin paradox of relativity theory, one of a pair of twins returns from a space flight at nearly the speed of light. It turns out that he has experienced less time than his twin, who stayed home. This could not be simulated in a man-made virtual reality with two subjects, but it would be possible in a virtual reality based on timeless consciousness. This and other issues concerning time are discussed in Chapter 3.

Quantum mechanics is presently the fundamental theory for all subatomic, atomic, and molecular phenomena, and I discuss it in Chapter 4. Since its inception, quantum mechanics has appeared to have something to do with conscious observation, and one of its founding lathers, Werner Heisenberg, regarded it as a theory of knowledge rather than as a theory of matter, Thus he took an idealistic view, in which perception and knowledge are taken as the basis of reality.

One might think that this bodes well for models in which matter interacts with consciousness. Unfortunately, however, the structure of quantum mechanics in its standard Copenhagen formulation makes it difficult to introduce consciousness as an active agent in the material world. However, the so-called "many worlds" interpretation of quantum mechanics allows us to take advantage of deterministic chaos to guide the course of events, just as we did in the case of classical physics. In a simulation, we can also avoid the innumerable splitting "worlds" of the many worlds theory by calculating only the world-branches that are needed. This is also a feature of the "quantum potential" version of quantum mechanics devised by David Bohm.

Of course, all talk of simulating quantum mechanical systems must confront the fact that even the most powerful computers of today are incapable of accurately simulating the behavior of a single protein molecule floating in water. However, we are using virtual reality models solely for thought experiments. In Chapter 5,1 review some thought experiments in which physicists have imagined computers that could faithfully simulate an entire universe. If their ideas are right, then the suggestion that we are already living in a virtual reality might also be right.

Do we see any evidence that consciousness can affect natural phenomena? One line of evidence is provided by the so-called weak paranormal phenomena. These include conscious influences on quantum-mechanically-based random number generators, as reported by Helmut Schmidt and by Robert Jahn and his colleagues at Princeton University. They also include the reported ability of people to observe things at a great distance—an ability described in pioneering studies at SRI in California and also studied by Jahn and his team. Not surprisingly, this ability of so-called remote viewing has also been of interest to the CIA.

The experiments with random number generators indicate that human intentions can apparently exert a small but measurable influence on complicated machines that are driven by a subatomic or atomic random process. These experiments do more than simply show that consciousness can influence matter. They show that complicated processes can somehow follow the will of a (human) conscious agent, even though that agent does not know about or in any way understand these processes. One way to explain this is to propose that the world forks quantum mechanically into multiple paths, and consciousness can somehow select a path to follow after the point when the split becomes humanly perceptible. One can use the virtual reality model to explore how this might work.

The remote viewing experiments are in some ways even harder to explain than the random number experiments. The problem is that people seem capable of viewing remote events before they take place. This is an example of the widely reported phenomenon of precognition, which involves perceiving alternate futures in advance. This seems to violate basic physical principles, but I point out that in a simulated world, it is not possible to systematically guide events without making calculations of alternate futures.

Here is why this is true. In a simple virtual reality model, there is a fairly direct connection between the conscious participant and the virtual body. For example, a participant wearing a data glove may directly control the motion of a virtual hand. However, to consciously guide a simulation that is faithful to the laws of physics, extra calculations are also needed, and these include projections of alternate future possibilities. This allows for precognition if we simply suppose that people are sometimes able to become aware of some of these projections.

In Chapter 7,1 discuss visions and hallucinations. These phenomena also require additional software standing between the conscious participant and the virtual body. Although a hallucination may seem to be nothing more than a breakdown of the brain's sensory processing, matters are not so simple. Reports of collective hallucinations and extremely vivid hallucinations suggest that image processing may occur outside the physical brain. This is possible in a virtual reality model.

The idea that image processing may occur outside the brain is supported by the near death experiences (NDEs), in which a person may report seeing verifiable events during a period in which the brain (and especially the visual modules of the brain) should not be functioning In a pioneering study, the cardiologist Michael Sabom showed that heart attack patients have often been able to describe detailed visual aspects of (he procedures used to resuscitate them from cardiac arrest. Many other studies have shown similar effects, and a study by the psychologist Kenneth Ring showed that congenitally blind people have reported detailed visionlike perceptions during NDEs. In Chapter X, 1 discuss this and point out that this evidence adds to the case made in Chapter 7 for additional sensory processing outside the brain. I ndeed, it goes further, since NDEs seem to involve conscious thought and memory storage during a time when the brain should be essentially shut down.

The evidence for reincarnation also suggests that memories can exist independently of the physical brain. The work of Ian Stevenson indicates that young children sometimes appear to spontaneously remember past lives. In many cases, it has been possible for investigators to identify the family of the remembered "previous personality" and to argue that the child could not have learned of this family through ordinary means.

Stevenson argues that children reporting past lives often exhibit interests, talents, and phobias connected with the previous personality. They may also exhibit birthmarks corresponding to wounds (often fatal) suffered in the previous life. The latter phenomenon is particularly interesting, because it suggests that the mind can impress patterns on the physical body. Stevenson gives several examples showing that within one life, mental images can affect the body in very detailed and specific ways. For example, in one case a man manifested vivid, deeply impressed rope marks on his arms after reliving an incident from years before in which he was bound with ropes. If the mind is at least partly independent of the body, this effect of mind over matter could explain how mental images formed in one life could carry over to another.

Thus far I have discussed paranormal phenomena that could conceivably be simulated within a virtual reality without creating major violations in the laws of physics. These phenomena require elaborate extra-physical calculations involving perception, but they do not require extraordinary forms of action. Thus the impression of mental images on the brain or body could be explained in terms of minute but systematic influences introduced into living cells. In Chapter 9, however, I discuss forms of reported paranormal action that seem to strongly violate the known laws of physics. These include phenomena in which objects are seen to disappear in one place and appear in another.

One might argue that such phenomena should be dismissed out of hand because we know they are impossible. However, another viewpoint is that these phenomena do exist and therefore the laws of physics are incomplete. Since the laws of physics have always been subject to revision, I take the latter approach. It would be convenient, but in my view dishonest, to avoid confronting these phenomena.

Most of the phenomena discussed in Chapter 9 could be explained by supposing that there exists an additional continuum (or more than one) in parallel with space as we know it. Matter can be transferred from one continuum to another, and some poorly understood form of physical interaction governs the process of transfer. We can model such phenomena in a virtual reality, where we are free to assume as many continua of space as we like. The problem is to work out the details of the transfer mechanism.
In Chapter 10,1 turn to the topic of healing. Unusual forms of healing seem to involve nearly all of the paranormal phenomena discussed in previous chapters. These include extreme cases in which serious disorders, such as blindness, are abruptly cured for no known reason. These may involve structural changes in organs or tissues that require transformations of the kind discussed in Chapter 9.

In all forms of unusual healing there is a need for someone or something to intelligently apply information. For example, selectively eliminating cancer cells requires knowledge of how to recognize a cancer cell. A cure that involves mobilizing the body's own protective mechanisms requires knowledge of how to invoke those mechanisms. The difference between usual and unusual healing is that the latter occurs in cases where the body's own resources lack sufficient knowledge or the means of applying it. In a virtual reality, calculations and information resources outside the virtual world can be used to guide such unusual repair processes in virtual bodies.

It is perhaps significant that unusual healing is often associated with reports of a glowing being who emanates a sense of love and wisdom. Reported visions of such beings parallel similar reports of beings perceived during NDEs. From the standpoint of the virtual reality metaphor, such beings might be conscious entities with a different kind of virtual body, living, perhaps, in a different virtual space. One may hypothesize that they play some administrative role in guiding the affairs of the virtual world.
Given a universal virtual reality system (which I refer to as Ground Reality), it is natural to ask how it came into being. In a man-made virtual reality, this involves a process of creation starting with people. People create the computer, the software, and the interface equipment, and some of them then begin their virtual adventure. In contrast, the modern scientific view is that everything has evolved, without intelligent guidance, by the action of subatomic particles interacting according to the laws of physics.

Of course, matters are not that simple. Astrophysicists have noted that the universe is adjusted in many ways to allow for life as we know it. Rather than postulate some intelligent cause with a predilection for life, some scientists have proposed that there is a primordial, unintelligent universe maker that spews out vast numbers of universes with random properties. Out of all those universes there are bound to be some suitable for our form of life, and we live in one of those. One can ask which hypothesis is more plausible, this one or the hypothesis of an intelligent designer?     

Since the virtual reality model assumes an original source of consciousness, it is certainly weighted toward the hypothesis of the intelligent designer. Yet we still must take into account cosmic and biological evolution. The simplest way to do this is to add intelligent guidance to the evolutionary process. This would be particularly relevant at certain key stages in this process, such as (1) the early universe, (2) the origin of life, and (3) the origin of highly intelligent life. In addition, iterative calculations already assumed in the virtual reality model can be used to achieve the postulated effects of random universe generation in a controlled and economical way. This is discussed in Chapter 11.

In Chapter 12,1 inquire into the nature of consciousness, which has been lurking in the background throughout the discussion. I have already assumed that consciousness is timeless, that it is capable of carrying out vast simulations with their own local time systems, and that it can manifest individualized conscious entities who become dramatis personae of virtual worlds.

To obtain further insight into the nature of consciousness, I turn lo contemplative traditions that have collected empirical data on this topic. I look mainly at two traditions, Buddhism and the Vaishnava tradition of Hinduism.

In these and other traditions, it is generally agreed that consciousness is paradoxically both unified and divided into parts. As the One, consciousness is the source and sustenance of everything, and as the many it is the awareness manifest in individual beings. In one sense, consciousness is the residue left over after everything explainable has been explained. It must be paradoxical, because otherwise it could be further explained. In another sense, the One consciousness contains everything, both explainable and unexplainable.

In Indian tradition, the Sanskrit word maya refers to the power to run vast simulations of virtual worlds. This book can be seen as a preliminary exploration of the idea of maya, or virtual reality, as a scientific hypothesis. In this hypothesis, the laws of physics—already mathematical—are set in the context of universal computation controlled by and interfaced with consciousness. This provides a framework in which the relation between consciousness and physical reality can be systematically explored.