Artificial Intelligence: The edge of research and beyond
Published: 29 Mar 2006 18:40 BST
While the practical aspects of AI have fallen short of early promises, research continues into genuine mechanisms of consciousness.
One of the biggest problems is that consciousness itself has proved impossible to define. For a long time it was thought to be the exclusive property of humans, but while few these days would deny it to the higher primates and some other mammals, there is no agreement about where, if anywhere, in the animal kingdom it ceases to apply absolutely.
Some animals are so simple that their nervous systems can be modelled in their entirety — the sea hare in particular has attracted interest because it has very large, relatively few neurons. You can even run a virtual sea slug on your Windows PC. Such experiments, although full of fascinating philosophical conundrums, don't seem a big step forward to AI.
Considerably higher up the evolutionary chain, IBM and the Ecole Polytechnique Fédérale de Lausanne are collaborating on Blue Brain. This is a Blue Gene supercomputer project to model 10,000 complex neurons configured as a rat neocortical column (NCC). This is a basic building block, a unit some 0.5 by 2mm big that's repeated throughout the brain, and is very similar to the human column. The researchers have mapped out the NCC through ten years of dissection and study, and have also built a model of an individual neuron with which to populate the model.
Blue Brain
As it stands, the computer has 8096 processors, each of which can model between one and ten neurons, is capable of 22.8 trillion floating point instructions per second, and is cooled by water from Lake Geneva. The first run of the full 10,000 neuron NCC took place as expected at the end of 2005: the researchers are now on version two of an expected ten versions of the NCC, but aren't saying anything about the results so far.
Once an NCC model is running well, the researchers plan to replicate it to create a full neocortex with around 20 billion neurons. There are plenty of other bits of the brain to recreate too, such as the hippocampus, cerebellum, visual cortex and so on, adding up to around 100 billion neurons in total with 1000 times as many connections. A computer powerful enough to model the entire brain could be built in the next ten years, say the researchers, although well before that point they expect to find useful results about brain data processing, neurological diseases, and how memory and sensation work.
Fortunately, there is plenty of evidence that the brain evolved in a modular fashion. One of the leading contenders for a theory of consciousness is homuncular functionalism, which says that different modules in the brain, none of them capable of consciousness by themselves, cooperate in a parallel processing matrix to produce the end effect of thought. Some of these modules are very well understood — the visual cortex, for example, has been most amenable to study and we now know how a scene is broken down into its constituent parts by grids of neurons set to trigger on basic components.
Internet equals the human brain
It has been noted that since there are around a billion PCs connected to the Internet, each with around a billion transistors, there already exists enough hardware connected together to simulate a human brain. As Kevin Kelly, godfather of Wired magazine and techno-social futurologist says, some of the Internet's processes already approach the capacity and mechanisms of the processes of mind. The Net "processes one million emails each second, which essentially means network email runs at 1Mhz. The Machine's total external RAM is about 200 terabytes. In any one second, 10 terabits can be coursing through its backbone, and each year it generates nearly 20 exabytes of data...
"Both the brain and the Web have hundreds of billions of neurons (or Web pages). Each biological neuron sprouts synaptic links to thousands of other neurons, while each Web page branches into dozens of hyperlinks. That adds up to a...
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