As Selfridge and Quaritch prepare to use lethal force against the Omaticaya and their forest, Grace Augustine protests, trying vividly to express what she believes she has learned of Eywa.
Grace has found evidence of “electrochemical communication” between the roots of Pandora’s trees, similar, she thinks, to the synaptic sparking between the neurons in a human brain. This is the basis of a natural neural network, like a human brain, but on a planetary scale: Eywa.
To the Na’vi, Eywa is their mother goddess—and, in a sense, their heaven. She takes them into herself when they die. We see this when the transfer of the essence of dying Grace to her avatar body is attempted in the Tree of Souls. This fails—but “all that [Grace] is” is taken into Eywa. Some essence of the dead Na’vi survive within Eywa, and the living can communicate with them by plugging a queue into a natural “portal” such as the Tree of Voices. This is why the amputation of Tsu’tey’s queue was so cruel; worse even than murder, it denies him immortality among his ancestors.
If Eywa were a human computer, all this is plausible if you believe in the much-anticipated technologies of “mind uploading”—mapping the brain and transferring its contents to a computer store—which we will look at in the next section when we investigate the avatar link process itself. But Eywa isn’t a Cray supercomputer. She has no silicon chips or optical links. She’s not even a human brain, a mesh of intricate biochemistry. As Parker Selfridge protests, “What the hell have you people been smoking out there? They’re just. Goddamn. Trees.”
Is it really plausible that a bunch of trees could be connected up into a network with anything like the “functionality” of a brain? And even if you believe a forest can become a brain, how smart can it possibly be?
Let’s start with Grace’s numbers.
Grace says that each tree on Pandora has “ten to the fourth” connections to the trees around it, and there are “ten to the twelfth” trees on the moon. This, she says, adds up to a global neural network with more connections than the human brain.
Can there really be “ten to the twelfth” trees on Pandora? Ten to the twelfth power means ten multiplied by itself twelve times, a number you’d write down as one followed by twelve zeros, with commas scattered according to taste: 1,000,000,000,000. That’s a million million—a trillion. By comparison, how many trees are there on Earth? In 2008 Nalini Nadkarni of Evergreen State College in Washington published an estimate, based on NASA orbital images of forest coverage. Her number was absurdly precise: 400,246,300,201—four hundred billion, or around sixty trees for every person on the planet. That’s about half of Grace’s estimate for Pandora. And given that much of Earth has been deforested by us humans in the last few thousand years, that’s close enough for me to accept Grace’s number as plausible, even though Pandora is smaller than Earth. Meanwhile the human brain is believed to contain around a hundred billion neurons—that’s ten to the power of eleven in Grace-speak. That’s a factor of ten less than Grace claims for Pandora’s tree number. As regards connections, on average a brain neuron has about a thousand connections to neighbouring neurons: that’s ten to the third, again a factor of ten less than Grace claims for the trees.
So your brain amounts to a total network of around a hundred trillion connections (a hundred billion times a thousand). And on that count, Grace is right that the network on Pandora is indeed bigger than the human brain, by a factor of about a hundred.
How does this compare to modern computers? Each neural connection in your brain can support about two hundred “calculations” per second. So that’s a total of twenty thousand trillion calculations per second, going on in your head, right now. (Granted it may not always feel like it.) That is, in the information technology terms I used in Chapter 19, the brain is capable of twenty petaflops. As we saw in Chapter 19, as of 2010 the most powerful non-distributed computer system in the world, the Chinese “Milky Way,” was capable of 2.5 petaflops—an eighth of the processing speed of the human brain, or about a thousandth the power of Eywa.
That sounds impressive, but you’ll recall from Moore’s Law (Chapter 19) that computing speeds and capacities are multiplying rapidly, doubling every fourteen months according to the TOP500 study. If this goes on, the fastest computer will pass the brain for sheer speed in just four more years—and it will pass the more powerful Eywa in a mere dozen years.
Or will it?
Grace’s estimate of Eywa’s complexity is based on a count just of the physical neural network of trees and their connections. This is quite reasonable from a scientist’s point of view, since it is all that Grace can “sample” and measure. But there is more to the complexity of any computer than a simple count of the links between its components.
One possibility is that the trees themselves are more than simple switches; perhaps they contain some internal processing too—which would up Eywa’s total processing power significantly. There is in fact a theory that the neurons in our brains are similarly more than simple on-off switches. Cambridge biologist Brian J. Ford is developing holistic theories about cells, which are complex organisms in their own right, and are capable of remarkably complex individual behaviours. Amoebas, for example, single-celled organisms, can build glassy shells by picking up sand grains from the mud. The cells of our bodies can perform similarly complex acts in support of body functions. Why, then, asks Ford, should we not expect that some kind of processing goes on within neurons, brain cells, themselves? Even the details of their output firings seem to include delays, nonlinear responses and other subtleties. “My hunch,” says Ford, “is that the brain’s power will turn out to derive from data processing within the neuron rather than activity between neurons.”
And what about connections beyond the intertwining of trees roots? The woodsprites are “the seeds of the sacred tree.” When they settle on avatar-Jake, during his first encounter with Neytiri, the Na’vi girl takes it as a sign from Eywa of great significance. But we see no physical connection between the trees and the woodsprites, no obvious neural links—and nor, indeed, have we any hint of how Eywa can predict Jake’s future. And later during the SecOps attack, the animals of Pandora, the viperwolves, banshees, hammerheads and thanators, join in the fightback. This is another expression of the will of Eywa, but again we see no evidence of a simple physical connection between trees and animals. In another odd incident, Mo’at, as tsahik, the shaman, presumably the closest of all the Na’vi to Eywa, tastes Jake’s blood on first encountering him. Is she sampling some kind of biochemical data to transfer to Eywa?
There’s clearly much to Eywa that isn’t obvious. But we do witness one remarkable expansion of Eywa’s apparent power beyond the limit of the core forest infrastructure.
In the Tree of Souls, when Grace and Jake are being taken into the Eye of Eywa to be transferred to their avatar bodies, the Na’vi of the Omaticaya clan all plug their queues into a glowing, dispersed root mass in the ground. The clan evidently becomes a kind of internet of the mind, with distributed computing going on in the “PCs” of the Na’vi brains in addition to the “mainframe” processor of the tree network.
Such networks can be extraordinarily powerful. According to an estimate published by Wired Magazine in June 2008, the billion PCs that are today connected by the Internet—along with smart phones, tablets and a host of other devices—amount to a single computer with a power equivalent to twelve thousand petaflops. That’s thousands of times the power of that top-end Chinese machine. A project called SETI@Home is an example of how this distributed power can be used. SETI searches of radioastronomy data for signals from extraterrestrial intelligences can be very hungry for computing power; there is a lot of sky to search and a lot of radio frequencies to listen on. Since the 1990s the task of sifting through the tremendous volumes of raw data has been parcelled out to a network of volunteers’ PCs, each of which contributes a fraction of its total power to the SETI quest. It’s an attractive project that offers you the chance of being the one to make first contact, at home…
To some extent a physical networking as in the Tree of Souls scenes is the ultimate expression of the Na’vi’s close sociability with each other—yet it’s much more than that. How must this linking feel? What would it be like, to be part of an internet of the mind?
A group mind might be a new layer of processing, superimposed on top of the central nervous systems of each of its members, passing information in a different, faster way. It would be a growth of consciousness, perhaps like the mind-expanding feeling you get when solving a puzzle, or finding the right strategy in a chess game—or when a scientist sees her hypothesis confirmed by a bit of new evidence, and the world makes a little more sense than it did before. Joined in Eywa, you would no longer be alone. You would share thoughts, feelings, memories. What would it matter if some of those memories were now stored outside your own skull?
And for the Na’vi, united in Eywa, this may have the strange consequence that to some extent the spirits of the ancestors are stored in the brains of their living descendants.
Eywa as a computing system is worthy of deeper study, for it shows signs of great sophistication in her processing and decision-making. The biochemical communication of the tree roots cannot be terribly fast, so planetary-scale Eywa may have a distributed decision-making system. When the woodsprites first detect there is something special about avatar-Jake, a holding decision seems to be made about him—Neytiri is instructed to keep him from harm—while, perhaps, the news is passed to higher levels of the hierarchy, and a deeper decision made. Later, Eywa clearly responds to the mass appeals of the combined clan, but she has options; there are clearly occasions when she feels it right to promote an individual. This is the Toruk Macto phenomenon, culminating in the selection of Jake himself.
But however smart she is, where did Eywa come from? How did she evolve?
Eywa is central to the Na’vi and their world. Jake learns that the Na’vi see the world as a network of energy, flowing through all living things; the energy is only borrowed, and you have to give it back. Eywa, the great mother, is at the centre of all this; she protects the “balance of life.” As such, perhaps she is a sister to our own Gaia.
As we saw in Chapter 2, according to theories developed first by James Lovelock, we believe that the Earth—its crust, the atmosphere, the water in the oceans and rivers and suspended in the air, and the biosphere, the world’s great cargo of living things—is a single, complex, highly interconnected system, constantly in flux under the pressure of powerful forces: the sun’s radiant energy which produces wind and rain and feeds life through photosynthesis, and Earth’s internal engine, principally the movement of the great tectonic plates and the outgassing of volcanoes. These forces drive tremendous cycles of mass and energy. And these unending cycles keep Earth habitable.
The main long-term challenge faced by life on Earth is what astrophysicists call the “Young Sun Paradox.” The sun, like all similar stars, is slowly brightening as it ages. In Earth’s early history the sun’s power output was only some seventy per cent of its current value. But despite this, as far back as we can see, temperatures on Earth’s surface have stayed about the same. Yes, there have been Ice Ages, but we have evidence from geology that on the whole liquid water has been able to exist on Earth’s surface for almost all of its history. Faced with a relentlessly brightening sun, some mechanism seems to have maintained the mean surface temperature of Earth in a range suitable for liquid water, and thus equable for life.
The key turns out to be carbon dioxide, the notorious “greenhouse gas” largely responsible for our current pulse of global warming. Carbon dioxide is injected (naturally) into the air by outgassing from volcanoes and other tectonic phenomena. It is removed by weathering, as the gas combines chemically with surface rocks, and by living processes; the bulk of the carbon in a tree trunk is drawn down from the air.
The outgassing is more or less constant, but the weathering rate and the productivity of life change with temperature. And because of that temperature dependence a global feedback mechanism has been operating, apparently for aeons. As the sun heats up, the carbon dioxide concentration is reduced, so that less heat is trapped, and overall the surface temperature stays constant.
This, and a number of other biochemical and geochemical feedback cycles, led Lovelock to formulate his Gaia hypothesis, that life has the ability actively to control its environment on a planetary scale, and thus to cope with changes such as the heating up of the sun. And all this emerged through self-organisation, as a natural outcome of the general increase of complexity on the planet. Lovelock’s ideas were greeted by a storm of scepticism, but the records of the evenness of temperatures in the past, and similar data, seem unarguable.
(This can’t go on for ever, though. When there is no more carbon dioxide left to draw down, the warming will at last be uncontrollable and the biosphere will gradually collapse. This will happen in less than a billion years. And remember that life on Earth is already some four billion years old. Gaia is old, not young, and Earth is closer to becoming a Mars-like desiccated world, like Burroughs’ Barsoom, than you might think.)
In the case of Gaia as we understand her, there seems no need for mind to be involved, no intention. “Gaia” is not alive. But what of Eywa?
Consider this. Alpha Centauri is an older star system than the sun, by some two hundred and fifty million years. That is a long time—four times as long as the gap between us and the dinosaurs—long even compared to the time there has been multicelled life on this planet, nearly half of that great span. So Pandora is most likely an older world than Earth, and its biosphere that much older too. And so Eywa must be older than Gaia.
Eywa, meanwhile, in preserving Pandora as a habitable world, has had significantly greater challenges to face than Gaia had. As a hazard, the slow heating-up of the sun has been relatively easy for Gaia to deal with; Gaia has had to become no smarter than a vast natural thermostat. Alpha Centauri A is heating up just as the sun is. But Pandora also suffers the tectonic agony of Polyphemus’ tides, and the tumultuous radiative and magnetic environment caused by its own magnetosphere and Polyphemus’. So Eywa has had to become a good deal more complex than Gaia—but has had the time to evolve ways to face its tougher challenges.
And, in the end, perhaps there was a sparking of consciousness, in a global network of ten to the twelfth trees.
All this is just my speculation. Perhaps the truth is entirely different. We have much to learn of Eywa, her true nature, her origin, and her ultimate destiny.
To paraphrase the British biologist J. B. S. Haldane, the universe is probably not just stranger than we imagine, but stranger than we can imagine.
That is surely true of Pandora. And this strange and remarkable world, Pandora, these remarkable people, the Na’vi, are what Jake Sully encounters when he enters the avatar link unit—and, astonishingly, looks out through the eyes of a body not his own.