Neuro-technology has long been a favourite of science-fiction writers. In “Neuromancer”, a wildly inventive book by William Gibson written in 1984, people can use neural(神经的) implants to get into the sensory experiences of others. Iain M. Banks came up with the idea of a neural lace, a mesh (网格) that grows into the brain, in his “Culture” series of novels. “The Terminal Man” by Michael Crichton, published in 1972, imagines the effects of a brain implant on someone who is convinced that machines are taking over from humans.

Where the sci-fi led, philosophers are now starting to follow. In Howard Chizeck’s lab at the University of Washington, researchers are working on an implanted device to administer deep-brain stimulation (DBS) in order to treat a common movement disorder called essential tremor. Traditionally, DBS stimulation is always on, wasting energy and robbing the patient of a sense of control. The lab’s ethicist (伦理学家), Tim Brown, a doctoral student of philosophy, says that some DBS patients suffer a sense of isolation and complain of feeling like a robot.

To change that, the team at the University of Washington is using neuronal activity associated with intentional movements to turn the device on. But the researchers also want to enable patients to use a conscious thought process to override these settings. That is more useful than it might sound: stimulation currents for essential tremor can cause side-effects like distorted (失真的) speech, so someone about to give a presentation, say, might wish to shake rather than make his words unclear. Giving humans more options of this sort will be essential if some of the more advanced visions for brain-computer interfaces are to be realized. Hannah Maslen from the University of Oxford is another ethicist who works on a BCI project. One of her jobs is to think through the distinctions between inner speech and public speech: people need a dependable mechanism for separating what they want to say from what they think.

That is only one of many ethical questions that the sci-fi versions of brain-computer interfaces bring up. What protection will BCIs offer against neural hacking? Who owns neural data, including information that is gathered for research purposes now but may be understandable in detail at some point in the future? Where does accountability lie if a user does something wrong? And if brain implants are performed not for treatment but to improve people’s abilities, will that make the world an even more unequal place?

“Two centuries ago, Lewis and Clark left St. Louis to explore the new lands acquired in the Louisiana Purchase,” George W. Bush said, announcing his desire for a program to send men and women to Mars. They made that journey in the spirit of discovery. America has ventured forth into space for the same reasons.

Yet there are vital differences between Lewis and Clark’s expedition and a Mars mission. First, they were headed to a place where hundreds of thousands of people were already living. Second, they were certain to discover places and things of immediate value to the new nation. Third, their venture cost next to nothing by today’s standards. A Mars mission may be the single most expensive non-wartime undertaking in U.S. history.

Appealing as the thought of travel to Mars is, it does not mean the journey makes sense, even considering the human calling to explore. And Mars as a destination for people makes absolutely no sense with current technology.

Present systems for getting from Earth’s surface to low-Earth orbit are so fantastically expensive that merely launching the 1,000 tons or so of spacecraft and equipment a Mars mission would require could be accomplished only by cutting health-care benefits, education spending, or other important programs—or by raising taxes. Absent (缺乏)some remarkable discovery, astronauts, geologists, and biologists once on Mars could do little more than analyze rocks and feel awestruck (敬畏的) staring into the sky of another world. Yet rocks can be analyzed by automated probes without risk to human life, and at a tiny portion of the cost of sending people.

It is interesting to note that when President Bush unveiled (公开) his proposal, he listed these recent major achievements of space exploration: pictures of evidence of water on Mars, discovery of more than 100 planets outside our solar system, and study of the soil of Mars. All these accomplishments came from automated probes or automated space telescopes. Bush’s proposal, which calls for reprogramming some of NASA’s present budget into the Mars effort, might actually lead to a reduction in such unmanned science—the one aspect of space exploration that’s working really well.

Rather than spend hundreds of billions of dollars to hurl (投) tons toward Mars using current technology, why not take a decade or two or however much time is required researching new launch systems and advanced propulsion (推进力)? If new launch systems could put weight into orbit affordably, and advanced propulsion could speed up that long, slow transit (运输) to Mars, the dream of stepping onto the red planet might become reality. Mars will still be there when the technology is ready.

What if a rollercoaster ride looked like this: no rails, no trains, just a chair on a mechanical arm (机械手臂) and a pair of glasses—VR glasses meaning virtual reality? That’s how it is in Nanchang, China, where a new amusement park relies entirely on digital entertainment.

Compared with a traditional theme park, this VR theme park takes up smaller space and much less time to build, but it brings visitors similar playing experience. The park uses VR for a variety of attractions, including the roller coaster ride, a musical video game where you have to hit the right notes, and a shooter in a completely unreal environment. It really gives you the feeling of reality.

The park wants to invest in a future technology and hopes to keep people’s fascination with virtual reality of life. For the technology, it is still highly experimental. What we want to do with virtual reality is to experience things in and beyond reality, but in fact the VR we can experience right now has a lot of limits. For example, although on the visual front, we can say we’ve broken past reality in our visual experience, there’s still a lack of physical feedback, meaning we can see the virtual world around us but we can’t feel them. That limits the technology’s appeal from many applications.

For now, one of its main uses is in professional training. For example, for pilots in a Boeing VR simulator(模拟器), a real touchable interface is combined with a virtual world outside. Some significant development is still needed before we can virtually wander around in our houses, go for a walk without leaving the house or actually hold a product in our hands before buying it online. Nanchang hopes to become a significant VR player in the future not just with digital rollercoasters.