In five years, every atom in your body will have been replaced with a different one. Are you, therefore, still the same person? How is it that you can change a person's brainal matter completely and have them be the same person? The information, life experiences and memories have been gradually transferred onto new atoms, molecules and cells. The actual medium on which "you" sit is not important: if you preserve your thought-patterns and cognitive maps, then the "you" is kept intact.
Nature can achieve this transfer because our bodies are designed for it. The precise way in which atoms and molecules are moved around is controlled, and our consciousness has evolved to sit on top of the storm. Can we reproduce this process artificially? Dr Hans Moravec imagined a particular way in which this might be achieved:
“You lie on a stretcher, next to a robot lacking a brain. Next, a robotic surgeon extracts a few neurons from your brain, and then duplicates these neurons with some transistors located in the robot. Wires connect your brain to the transistors in the robot´s empty head. The neurons are then thrown away and replaced by the transistor circuit. Since your brain remains connected to these transistors via wires, it functions normally and you are fully conscious during this process. Then the super surgeon removes more and more neurons from your brain, each time duplicating these neurons with transistors in the robot. Midway through the operation, half of your brain is empty; the other half is connected by wires to a large collection of transistors inside the robot's head. Eventually all the neurons in your brain have been removed, leaving a robot brain that is an exact duplicate of your original brain.”
Sounds simple? When public scientist Michio Kaku commented that the mechanical, surgical and technological difficulties are "truly formidable"2 it seems to be an understatement. This isn't because there are between 8 and 10 billion neurones in the brain3 and that this would take an impossible immense effort to duplicate, but also because each neurone can have 1,000 to 10,000 synaptic connections to other neurones. Each connection would have to be duplicated too. Sounds impossible? It is only the beginning of the problem! Because synaptic connections aren't just connected electronically - they also perform logical functions. They only fire when the correct pattern of inputs is received, in the right frequency, at the right times. And the connections learn new behaviour. If the new medium is going to contain a working copy of someone's consciousness, all of these tiny details need to be mapped and re-instated in every single synaptic connection. And they've got to be able to learn and behave in the same way, otherwise, our consciousness could be radically undermined. All it takes is a change in the learning pattern of neurones, and a range of problems could surface which were impossible to predict in advance. The worst part is that there are surely mechanisms of data transfer between neurones that we simply don't understand, and, that we don't even suspect. It is likely that there will never be a point where we know enough and can do enough to duplicate a conscious brain.
There have been many science fiction stories in which human consciousness is transferred onto a new medium. In the film Lawnmower Man (1992) a subject of a science experiment exhibits radically increase intelligence via virtual reality setups, and eventually completely uploads himself to a computer system in order to attempt to spread to all of the world's computers. In the film Tron (1982), a scanner obliterates a human body and recreates it inside a virtual world with no apparent loss of conscious fidelity. This opens up the final and most fantastical possibility: the abandonment of the human body, with its frailties and biological limitations, in favour of a purely virtual and Internet-based existence.
"The Singularity" is the idea that technological development will at some point reach a point whereby human consciousness and existence is massively transformed and in modern times, the dominant idea is that this involves the uploading of an entire persona onto computer servers which maintain and support consciousness in place of the brain. This concept engenders a lot of criticism. Massimo Pigliucci, professor of philosophy at the Graduate Center of the City University of New York and a fellow of the American Association for the Advancement of Science, writes in The Skeptical Inquirer that the whole concept is pseudoscience5. He humorously states we should think of it, with its effect of overcoming death, "as the Rapture for nerds". His real concern is that the underlying electronics simply isn't up to the job of sustaining sentience.
“The whole idea of being able to upload one's consciousness assumes a strong - and not at all validated - version of the computational theory of mind. [...] Human psychology evolved alongside a body capable of sensations, emotions, and so on - not just pure thought. [...] Sounds like a recipe for disaster to me.”
Massimo Pigliucci (2012)5
Some of the problems stem from the very way that our brain is wired, and the way in maintains consciousness in tandem with biological and bodily feedback. These systems do not behave like anything that we can currently virtualize on any kind of computer. Our brains all but require squidgy, irrational and constant input. All experiments where the brain is divorced from normal inputs result, relatively quickly, in serious cognitive dysfunctions. Without such ordinary inputs, we experience extreme discomfort, hallucinations and continued confusion, very quickly losing the ability for constructive and coherent thought after just a few days6,7.
“Without the stimulus and guidance of emotion, rational thought slows and disintegrates. The rational mind does not float above the irrational; it cannot free itself to engage in pure reason. [...] In the brain-in-a-vat fantasy of neurobiological theory and science fiction, the organ in its nutrient bath has been detached from the impediments of body and liberated to explore the inner universe of the mind. But that is not what would ensue in reality. All the evidence from the brain sciences points in the opposite direction, to a waiting coffin-bound hell of the wakened dead, where the remembered and imagined world decays until chaos mercifully grants oblivion.”
In conclusion, the problems of sustaining human consciousness apart from the brain are far more than merely procedural. The advances required are in surgical precision, electron scanning and brain-mapping, circuitry and virtualisation, inputs and outputs systems are all still beyond the pale, with no concrete solutions in sight. The writing on this topic, under the guise of transhumanism, will continue because the possibilities are enticing, combining a sense of (digital) adventure with science fiction fascination and a yearning for enduring longevity without biological malaise.