ERIK DREYER/GETTY
and autoscopic hallucinations (seeing one’s body in extrapersonal space). Damage to the frontal lobes could disturb the sense of agency, with limbs developing a recalcitrant will of their own. The extended self, too, was neurologically fragile. It could be gradually dismantled by dementia, or shattered by a sudden viral attack, the story of the self dissolved with the dissolution of memory. In contrast, a deep-brain stroke or injury to the frontal lobes could leave memory unaffected but recalibrate the machineries of emotion and temperament. The story continued, but the central character had changed beyond recognition. Sometimes the brain’s storytelling mechanism itself broke down, resulting in the confabulation of fictional, often fantastical, autobiographical distortions. As science writer John McCrone put it, we are all just a stumble or burst blood vessel away from being someone else. Selfhood is malleable. That was the message. The neurological diseases that were then still prevalent tended to carve human nature at its joints in such ways, and one occasionally saw what appeared to be clear dissociations of the two “selves”. I remember an epileptic patient telling me of her intermittent loss of identity, a condition known as transient epileptic amnesia. Her surroundings would suddenly feel unfamiliar, and then she would begin to feel unfamiliar to herself. Soon she had no idea who she was, where she was or what she was doing. She was stripped to the minimal self: a floating point of subjective awareness untethered by identity. In other, rare, cases I saw the opposite: the minimal self dissolving, leaving only the story of the extended self. One patient had a strong
CHRIS MCKAY
RODNEY BROOKS
A “second genesis” of life! In the next 50 years we may find evidence of alien life frozen in the ancient Martian permafrost, perhaps dead but biochemically preserved. We may find it on the surface of Europa. We may find it spewing out of the geysers on Enceladus. The most bizarre thing would be to find life on Titan, growing in liquid methane. There is even a chance we will find alien life forms here on Earth – what some have called a shadow biosphere. How different might alien life be? It might be as different as English is to Chinese.
Show a two-year-old child a key, a shoe, a cup, a book or any of hundreds of other objects, and they can reliably name its class – even when they have never before seen something that looks exactly like that particular key, shoe, cup or book. Our computers and robots still cannot do this task with any reliability. We have been working on this problem for a while. Forty years ago the Artificial Intelligence Laboratory at the Massachusetts Institute of Technology appointed an undergraduate to solve it over the summer. He failed, and I failed on the same problem in my 1981 PhD. In the next 50 years we can solve the generic object recognition problem. We are no longer limited by lack of computer power, but we are limited by a natural risk aversion to a problem on which many people have foundered in the past few decades. If enough people spend enough time working on it, taking ideas that we are getting from psychophysics and brain imaging, I am confident we will come up with at least partial solutions. When we do, the possibilities for robots working with people will open up immensely.
Chris McKay is a planetary scientist at NASA Ames Research Center in Moffett Field, California
Rodney Brooks is Panasonic Professor of Robotics and director of the Computer Science and Artificial Intelligence Lab at the Massachusetts Institute of Technology
60 | NewScientist | 18 November 2006
061118_F_5_Consciousness.indd 60
www.newscientist.com
7/11/06 5:31:42 pm