The Science of Avatar

by Stephen Baxter

  But even if Jake’s brain is read and written to non-invasively by scanners in the link unit, how is the avatar’s brain accessed? This is the other end of the link, after all, and data must be uploaded and downloaded to it at the same rate as to and from Jake’s brain. In this case the interfacing technology is contained inside the avatar’s brain. As the avatar body is being grown in its tank, the brain is grown with a reception node embedded in its cortex. We haven’t got this far in reality, but there have been experiments with “partially invasive BCIs,” where you lay a thin plastic pad full of sensors within the skull, but outside the brain.

  Brain hacking is clearly a tremendous challenge, on which we’ve made barely a start. In the movie, the use of the word “psionic” in the description of the link technology is telling. “Psionics” is generally taken to mean the study of paranormal powers of the mind, such as telepathy, telekinesis, precognition and so forth. It seems to have been coined by science fiction editor John W. Campbell as a fusion of “psi” from psyche, and “onics” from words like electronics, to imply a more scientific framing of the subject. Perhaps we can infer from the use of that word that the science of the twenty-second century has advanced far beyond what is known now; perhaps there are principles at work in the link units of which we have no knowledge.

  We can however assume that the link process will be mediated by a computer system vastly more powerful than either Jake’s brain or the avatar’s. The enormous artificial intelligences of the future, as predicted by Moore’s Law, will not be baffled by the computational size of the brain, nor, I would guess, by the challenge of decoding the brain’s many signals. It will be like managing the problem of interfacing an Apple Mac to a Microsoft PC by connecting them both up to that monster Chinese “Milky Way” supercomputer.

  And if brain hacking does become possible many remarkable applications open up, beyond the driving of avatars. Fully immersive virtual reality, where we started this discussion, would become trivially easy. Roaming around inside the tremendous computer memories of the future, you could have any experience you want, real or fantastic, as richly detailed as the real world, and you could run them at any speed (compared to real life) as you liked: a twelve-year trip to Pandora and back crammed into a morning coffee-break. If you suffer from “Avatar withdrawal” after watching a mere movie, you might never want to come out of a simulation like that at all.

  And VR might become so good that you couldn’t tell what is real and what is virtual, like the characters in the movie The Matrix. I’ve suggested myself that one resolution of the Fermi Paradox (see Chapter 26) is that we’re stuck inside a virtual reality suite run by the aliens, to hide the real universe. Oxford-based philosopher Nick Bostrom says that not only is it possible that we’re living in a virtual reality generated by some advanced culture, it is probable that we are—there are always going to be more copies than the original reality, so it’s more likely you’ll find yourself inside a copy than the original…

  We’ve come a long way with this speculation, but we haven’t yet got to the bottom of the mystery of Jake’s mind-linking. For he is interfacing with a body quite unlike his own. And that presents yet more fascinating challenges.

  33

  WHAT IS IT LIKE TO BE A NA’VI?

  There are lots of subtleties in the way Jake Sully’s mind would have to be mapped into the avatar’s brain, beyond the issues of coding, data transfer rates and all the other information-technology stuff we touched on in the last chapter.

  An avatar body is more like a Na’vi’s than a human’s. So to run his avatar, Jake, a human being, has to learn how to be a Na’vi.

  I find it a lot easier to imagine that I could drive a fully human avatar than that I could drive an avatar of a Na’vi. Or indeed, an avatar of my own little dog.

  For one thing, I’m well aware that my dog doesn’t see the world as I do. This is evident when we watch TV, at least on an old analogue set. Such sets present a series of still images quickly enough to fool the human eye into thinking it’s seeing continuous motion. But my dog’s eyes were evolved for a subtly different purpose than mine, and their “flicker-fusion rate” is faster than mine. He can see the individual frames, and indeed the blanks between them, and so to him the TV screen is like a dance floor under a strobe light. That’s why an analogue TV never captures his interest (but digital sets remove the flicker-fusion problem, and the dog is fascinated, at least by programmes featuring other dogs).

  If this is a challenge for my little dog and me, who as mammals are pretty close relatives in the grander scheme of Earth’s family of life, it’s going to be ten times more difficult for Jake and his avatar. After all, Jake and the Na’vi are from different worlds altogether.

  The sensory functions of Jake and his avatar overlap, but not completely. For example a Na’vi’s sight goes beyond the human range, into the near infrared, to allow night vision. This provides input which has no analogue in the human sensorium. You could imagine transforming the input images somehow so that they map over the human range; it might be like wearing a soldier’s infrared vision enhancer in a combat zone, and having its images superimposed over the visuals in a heads-up display. But enhancements like that would provide an entirely artificial picture, and would be nothing like what the Na’vi actually sees. Jake has to learn to see like a Na’vi, not like a human with enhancing goggles.

  What about hearing? Perhaps those mobile Na’vi ears give their hearing a three-dimensional quality like nothing in the human sensorium. There would be no mechanism in Jake’s head to process such information—no analogy in Jake’s sensory world to map onto.

  With motor functions it’s a similar picture. It’s easy to imagine Jake’s brain running a fully human avatar. The region of Jake’s brain that “runs” his right hand can be made, through the link, to “run” the avatar’s right hand; there could be a one-to-one mapping between the driver’s brain and the avatar’s body functions.

  But there are areas where a Na’vi’s body function doesn’t map perfectly onto a human brain. The most obvious is that prehensile tail. Jake has no subroutines in his head to work a tail (or if he does they are vestigial, relics of very ancient days when human forebears did have tails). More than that, he doesn’t know how it feels to work a tail. Another entirely nonhuman aspect of the Na’vi experience is the neural link to other animals through the queue. No human has ever experienced such a link; we have no neural subroutines in our brains to process the data coming into the avatar’s head from the direhorse or the banshee.

  In 1974 an American philosopher called Thomas Nagel published a paper that has become a classic in its field, called “What Is It Like to Be a Bat?” Exploring issues of consciousness and the “mind-body problem”—how mind arises from the machinery of the body—Nagel was attacking what he called a “wave of reductionist euphoria.” Reductionism is the breaking-down of concepts into smaller pieces for the purpose of measurement and understanding. Nagel argued that consciousness must be tied to “the subjective character of experience,” and so, perhaps, can’t be broken down into little bits.

  Nagel’s use of a bat as an example is instructive. A bat is a mammal, like me and my little dog, so pretty closely related to us both, but a bat experiences the world entirely differently from us, primarily through its sonar echolocation system. Its brain processes sound inputs into location and distance information. Inside its head, a bat must “see” the world as a kind of shadowy three-dimensional theatre, painted in auditory data.

  Nagel argued that it’s impossible for us to imagine how it must be to be a bat. Even imagining a transition from one form to another—to lose your sight, to have leathery wings strapped to your body, to be hooked up to a sonar system—is an artificial exercise. And (though Nagel didn’t take his argument in this direction) the “reductionist” idea that you could brain-scan a bat and download it into a computer store, without it losing its sense of self as a bat, begins to look a bit silly. Maybe we are
n’t just abstract information flows. Maybe everything about our cognition is shaped by the way that we’re embedded in our bodies, because that’s the way we apprehend the universe.

  To restate Nagel’s question: what is it like to be a Na’vi? The mapping of Jake’s brain to a Na’vi’s body must require a lot of interfacing, beyond the basic spark-by-spark level of neural inputs and outputs, even beyond the higher-level mapping of Na’vi experience to a human mind. Somehow, the governing software must render the sensations of being a Na’vi into forms capable of being comprehended by Jake, at both sensual and inner levels.

  However it works, evidently the psionic link does function in giving the driver a fully immersive experience, as we see from the scenes of Jake’s very first linking—his delight in his new body, and in the world he apprehends. And as the movie goes on we see Jake being drawn steadily into the new world at the expense of the old, almost like an addiction to a computer game, until, as he says, the dream of Pandora seems more real than his own humanity.

  And ultimately, following the logic of his personal quest, Jake makes the final step: to leave his humanity behind altogether.

  34

  THE TRANSMIGRATION OF JAKE SULLY

  In the final scenes of the movie Avatar, Jake Sully’s human body lies side by side with his avatar in the Tree of Souls.

  This is the conclusion of the long journey Jake began when he left Earth on Venture Star. Like Grace Augustine before him, Jake is attempting to complete a full crossing from his broken human body into the avatar. He must pass through the “Eye of Eywa” to do this. The process failed for Grace, though she was preserved in the “buffer” of Eywa’s neural-net memory.

  But, when his avatar’s eyes snap open, we see that Jake succeeds.

  Once again these scenes in Avatar are reflections of very old myths, of the transference of souls from the body. The ancient Greeks believed in the transmigration of the soul: after death your shade drinks from the River Lethe, loses all memories of past lives, and moves into another human form and is reborn. Hinduism similarly contains a belief in transmigration.

  Today we are still grappling with the implications of such ideas. Jake submits to Eywa, hoping she will choose to “save all that [he] is” in the avatar body. “All that he is”: a concise way to sum up the deepest mystery of human existence. The key questions are: is the copy of Grace inside Eywa really “Grace?” And is Jake in the avatar body really “Jake?”

  Before the final transfer, it is evident from shots of Jake in the link tank as he drives the avatar body that there is something of him left behind in his human carcass. His closed eyes flicker, as if he is in “REM sleep” (rapid eye motion). Maybe avatar-driving is like an exceptionally vivid dream. Indeed, a good bit of what makes up Jake must remain in the human body, rather than be downloaded into the avatar’s head: his memories of Earth, for example. And memories from his avatar experiences are stored back in his own brain, for he remembers the experiences after the link is broken. (Transferring memories presents another technical issue for the link mechanism, incidentally. Your memory of the last sentence you read isn’t stored in one place in your head like a little photograph, but is held as a distributed pattern of neuron sparkings.) For Jake to complete the crossing into the avatar, all these memories must be ported over, along with everything else that is a part of his personality.

  But even if the entire contents of Jake’s brain are read and downloaded successfully into the avatar, does “Jake” come with it too? What is “Jake?” That is, what is his consciousness, and how is it related to his brain and body?

  We are now venturing into waters so deep they make quantum mechanics look like a Sudoku puzzle. Philosophical musings on the nature of the self date back to Plato. In the seventeenth century, Descartes, with his famous declaration “I think therefore I am,” was an early modern western thinker about what has come to be called the “mind-body problem,” the question of how something as ineffable as the human mind can be connected to the lump of meat that is the human body. But other cultures have considered the problem too. The Buddhists, it seems, believe that consciousness is the primary reality.

  The position of many modern neuroscientists, as well as visionary futurologists like Ray Kurzweil, is that “Jake,” his mind, everything important about his essence—“all that he is”—derives from the patterns of activity in his brain. Consciousness is an “emergent” quality, and it arises the way a higher-order property like the temperature of a mass of gas “emerges” from the motion of the collection of individual molecules that make up the gas. And if you copy that brain pattern with perfect fidelity, and then if you download that pattern into another substrate, biological or artificial, then yes, that copy still “is” Jake in any meaningful sense.

  But not everybody agrees. Philosopher Daniel Dennett has argued the whole Cartesian question of how the mind arises from the body, as if there is a conscious being riding around inside an unconscious carcass, is the wrong question to ask. The mind-body problem would melt away if we could see the workings of the brain closely enough, Dennett says. Consciousness must arise from a flow of information processing between different centres in the brain, so there is no single central consciousness. Consciousness is more like something you do than a thing you are. And if that’s so, is it meaningful to talk of transferring it from the brain at all?

  I think it’s true to say that consciousness is still largely a mystery, about which the philosophers and neuroscientists find it difficult even to agree to definitions of terms. Maybe we’re going to have to learn a lot more about how the brain itself works first before we can produce a compelling theory. But new directions in consciousness studies are being followed, including the opening in April 2010 of the new Sackler Centre for Consciousness Science at the University of Sussex in England, which will bring together such disciplines as psychology, neuroscience, medial sciences, computer science and AI studies.

  Perhaps in our analysis of mind uploading we have been too reductionist—too eager to break the notions of self down into little pieces. Maybe reality is more subtle. We have seen evidence that there is more to Eywa than the neural network that the great reductionist Grace Augustine was able to sample. Perhaps there is more to “Jake,” to the self, to “all that he is,” than a mere side-effect of neural networks. Maybe, somehow, Eywa really does welcome something like the souls of Grace and Jake into her care, and into the avatar.

  And ultimately what Eywa offers Jake and Grace is immortality. If you can upload yourself to a computer store, just as Grace is uploaded to Eywa, then you need never die. Your logical essence has been detached from your physical body, and “you” need no longer be doomed by your body’s ageing process. As future generations of computer technology emerge, you could simply continue to upload yourself to the latest upgraded hardware. Some futurologists like to speak of the coming “singularity,” when thanks to the advance of technology we will merge with the artificial super-brains of the future, and intelligence will advance exponentially.

  Perhaps Avatar’s Eywa is a “green” singularity, a merging that is the ultimate destination for all life.

  In following the final step of Jake’s journey, from human to the non-human, Avatar has made us confront the deepest questions of our existence. But we have reached the limit of scientific speculation, and can see no further.

  EPILOGUE

  In this book we’ve followed Jake Sully’s journey from a ruined Earth to a new world, from a broken body to health and vigour, from human to the alien—from despair and cynicism, to redemption and even love. And in working through the science that might underpin Jake’s journey we’ve glimpsed a dark but realistic future for Earth, exotic but feasible technologies for crossing the gulfs between the stars, and a marvellous but not impossible living world and its people. As in all the best science fiction Avatar confronts us with the limits of the possible, and makes us consider what those limits tell us of our humanity.

  B
ut Jake gets to stay on Pandora. We have to come home now, just as Jake’s fictional predecessor John Carter was reluctantly brought back from Barsoom: “For ten years I have waited and prayed to be taken back to the world of my lost love. I would rather lie dead beside her there than live on Earth all those millions of terrible miles from her” (from Burroughs’ A Princess of Mars).

  But if you still find yourself suffering from “Pandora withdrawal,” you might reflect on what Joe Letteri said in his acceptance speech for Avatar’s visual effects Oscar win: “Just remember the world we live in is just as amazing as the one we created for you.”

  He’s right. As we’ve seen, there is a “Pandora” in our own solar system: a world orbiting a gas giant, with low gravity and a thick atmosphere, with lakes and mountains, and rain that falls in huge, slow-motion droplets… In the stars even further away than Alpha Centauri, we are discovering worlds without number… And we are learning how minds might be enhanced, joined, and maybe even projected into “avatars,” real and virtual.

  And then there’s Earth.

  When avatar-Jake first encounters the nature of Pandora, you can feel the wonder of a traumatised young man as he connects for the first time with a living world, and, maybe, discovering something inside himself he didn’t know was missing. Charles Darwin, arguably the first human being ever to really understand how life on Earth works, felt this wonder too: “It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us… There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved” (from Origin of Species (1859)). It’s almost as if Darwin’s Beagle took him to Pandora.