The mystique and fear surrounding artificial intelligence (AI) tends to focus on the idea of sentient machines somehow challenging man's role on earth, conjuring up images of HAL, the softly spoken computer with malicious intent. Less talked about is the reverse idea of humans adopting some of the qualities of machines via embedded or implanted chips. As technology advances so the gap between human and machine closes, fuelling ever more feasible science fiction scenarios that inevitably provide us with new worries. To some, the idea of computer-assisted bodies fuels fears that we are all about to become automatons like the evil cyborg men made famous in Dr Who. In reality, the relationship between computers and us is far more contrived, giving machines powers that serve the most mundane purposes. While we worry about the idea of contaminating our bodies with technology thousands of our pets are unconcernedly roaming around with chips implanted in their necks. The use of chips in pets -- now a legal requirement for anyone wanting to ship a cat or dog abroad -- seems fairly harmless but suggestions that it be extended to their owners is greeted with less enthusiasm. But such implants are no longer the preserve of fiction. One US-based company, Applied Digital Solutions, has already developed a microchip -- dubbed Digital Angel -- which was originally marketed as a tracking device for humans. The makers dwelt on benevolent uses of the chip -- such as allowing doctors to monitor heart conditions. But despite its short lifespan (it was only launched in October) the company has decided to abandon its embedded chip idea in favour of wearable devices. "We are not pursuing any applications for embedded chips and we have moved away from that for a couple of reasons," says a spokesman for Applied Digital Solutions. While he insists that the main reason is an economic one -- a small end market and the amount of time such a technology would take to get FDA (Food and Drug Administration) approval are the reasons he states -- he also cites privacy worries and ethical issues. "We don't want the adverse publicity. There are a number of privacy concerns and religious implications -- fundamentalist Christian groups regard it [implanting computer chips] as the Devil's work," he says. It would seem that even those companies that had hoped to turn the notion of embedding chips into humans into a viable business opportunity are having second thoughts. Perhaps they are put off by the myriad civil liberty groups willing to fight tooth and nail to prevent such technologies being adopted. The biggest concern appears to be that once humans are fitted with computerised implants, all other Big Brother fears will look like a walk in the park. The theory goes that once such devices are put inside of us, it will be a quick and easy step for governments to centrally coordinate and monitor our movements. It would certainly make all the current RIP-based plans for Internet snooping appear costly and technically complicated way in comparison. Some privacy advocates claim governments already have the technology to spy using human implants and worry that in a society obsessed with surveillance such devices could be the last straw. Head of Privacy International Simon Davies believes implanted chips that could be employed as tracking devices could be as little as five years away. "The pattern for these things is they start as medical uses, then becomes used in the military or in prisons. Then become voluntary, then compulsory," he says. For the time being though, Davies is more concerned by the likelihood that devices like mobile phones and PDAs could be used to monitor our activities. In the future, he argues, nanotechnology, where atom-sized robots are used, could pose a very real threat to privacy. "Then technology will be as universal as the smallpox injection, which raises very grave privacy issues," he says. Even scientists, usually relatively blase about such issues are concerned about the possibility of a "chip network". Professor Brad Myers of the Computer Science department at Carnegie Mellon University in the US raises no objections to the idea of chip implants, but concedes he is worried about government use of such technology should it become the norm. "If the chips are wirelessly connected to networks, that opens up a whole new set of issues," he says. BT -- which has followed developments in the use of chip implants closely -- believes communications using smart chips will have "profound implications on how people communicate with networks". The company's chief futurologist, Ian Pearson, is not convinced however that implants will necessarily be the favoured method of use. "There is nothing you can do with embedded chips that you can't do with wearable ones, and I can't imagine there will be queues of people lining up to get chips embedded," he says. He predicts the idea of wearable identity chips could be implemented within five years. Pearson too is concerned about privacy using implanted chips: "They give an extra capacity for surveillance. We are already living with complete invasion of privacy and I would hate to live in a society that was policed to the extent embedded chips would allow," he says. Take me to Pt II/ Privacy versus benefits to human understanding. In the future your PDA will think for you. You will be its Personal Person Assistant. Find out how the future could be in ZDNet's Artificial Intelligence Special. Have your say instantly, and see what others have said. 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