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.