These days science and science fiction are hard to tell apart, and it could be argued that pure science has the edge when it comes to provocative visions. Thus Kevin Warwick, a British professor who became famous when he implanted a chip in his arm that connected him to a computer. Hooked up over the Internet, Warwick could make a remote mechanical arm move merely by flexing his own arm.

Warwick became, for a time, a "cyborg" -- a human being whose body uses electromechanical devices to supplement his or her normal physiology. The professor forsees the day when everyone will want to be a cyborg.

After all, we're talking about the ultimate mobile connection, one that would augment the brain with the vast resources of the Internet.

So when Warwick connected to the Net, did his body have its own Web address? Evidently so, for it's said he was careful not to let the details out for fear hackers might try to hijack his arm. The scientist told November's Digital Identity Forum in London that cyborgs had better watch out, for software viruses and biological viruses will one day merge, making humans the ultimate hacker target.

It would be easy to dismiss Warwick as yet another futurist with a grand vision, like Ray Kurzweil, who thinks that one day we'll all upload our personalities to computers to achieve immortality. And then along comes a company like Cyberkinetics (www.cyberkineticsinc.com/), with a practical demonstration of something less grandiose, but in the scheme of things far more beneficial to society.

The Cyberkinetics system is called BrainGate. The idea is to help people with movement problems, such as those with strokes, severe spinal injuries or amyotrophic lateral sclerosis. A BrainGate implant could one day allow such people to control a computer -- writing e-mail, controlling a TV, or answering a phone -- solely with their thoughts.

How do you make an interface between computer and brain? Quadriplegics in the company's trials will have chips implanted in their brains that are connected to computers through an opening in the skull. The device can then be "trained" to identify patterns in brain activity that are associated with physical movements. After a period of training, the patients should be able to manipulate a cursor merely by duplicating the thought pattern.

And in at least one case, it works. A test subject whose device was inserted in June can check e-mail, turn lights on and off and control his television by forming the right thoughts in his head. Recruits are now being sought for further studies on both safety and practicality.

Meanwhile, at Duke University, neurobiologists Dennis Turner and Miguel Nicolelis are extending thought control to include external devices. In widely reported work, Nicolelis has already been able to teach monkeys to control a robot arm using nothing more than brain signals. Now the idea is to create "neuro-prosthetic" tools so paralyzed people can interact in more natural ways with the world.

You can imagine what freedoms this work could eventually bring to the severely disabled. The team is working on an interface between the patient and a prosthetic device. But a robot arm moved by thought control is only the beginning: Using thoughts to control a wheelchair would provide new mobility, and neurally controlled keyboards could open new ways to communicate.

These are wonderful results for the disabled. How far they spread in society at large is another matter. Kevin Warwick thinks we'll all become cyborgs one day, with unaugmented humans relegated to the status of sub-species. I'll leave such visions to the futurists. What concerns me is today's reality: The cyborg solution holds remarkable promise for people desperately in need of a breakthrough.