'Please, sir, could I have less?'

Bill McKibben argues that our thirst for technological progress threatens the nature of humanity

These are the days of miracle and wonder." The world has been transformed in the years since 1986 when Paul Simon borrowed those words from the New Testament. And it promises to change even more as new technologies are released into the eager hands of a world addicted to progress. While many dream of a future filled with enhanced human beings and technology so advanced that it will be indistinguishable from magic, a small but growing movement questions whether some avenues are better left unexplored.

These aren't the Luddites you might expect. Sun Microsystems chief scientist Bill Joy registered his concerns about out-of-control progress in Wired magazine several years ago. Francis Fukuyama's "Our Posthuman Future" warned of a time where society as we knew it would no longer exist thanks to genetic engineering.

But unfortunately, not enough scientists are questioning the ethics of their research, leaving that role to such people as Bill McKibben. Best known for "The End of Nature" (1989), McKibben has now turned his attention to several new technologies that he believes could spell the end of what it means to be human. "Enough" is a reflective essay that surveys advanced technologies, what the leading minds feel about them, and the profound effects they'll likely have on society.

Genetic engineering, nanotechnology, robotics, and other related technologies may, he writes, "alter our relationship not with the rest of nature but with ourselves." McKibben argues that this debate is too important to be left to scientists. "Must we forever grow in reach and power?" he asks. "Or can we, should we, ever say, 'Enough'?"

The most troubling technology that McKibben explores, at least on an ethical level, is genetic engineering. While medical applications to cure or alleviate suffering raise few objections, McKibben is worried about germ-line genetic engineering, the technology that has parents dreaming of 6'2", blond haired, blue-eyed physical marvels with IQs of 200. It's a technology that McKibben argues could destroy the notion of individualism.

Cheerleaders of genetic engineering tend to dismiss that sort of thinking as fear mongering, but McKibben raises a host of troubling questions that proponents tend to avoid.

He suggests, not without some foundation, that a child created in a laboratory with the physical and mental traits that parents prescribe could become a kind of automaton. If you're a lover of music, for instance, you might be tempted to have that programmed into your child. That child and all his progeny might then have an affinity for music, but they wouldn't have that preference by choice.

And what happens when parents spend millions to create the child of their dreams, but the result is a "disappointingly" normal child. Will they go to court and declare their child defective to recover damages? As genetic technology progresses and parents contract for multiple offspring, will they view their earlier children as obsolete versions, still to be loved but clearly not as capable as their younger siblings? Will those enhanced look upon us and decide we might not be worth keeping around?

While McKibben raises profound concerns about genetic engineering, he's less successful when dealing with nanotechnology, robotics, and increasingly powerful computers. He paints a not particularly convincing picture of a future in which machines eventually surpass the power of the human brain and supplant humanity - assuming we're not wiped out by a man-made virus run amok.

These are technologies that he admits could one day eliminate want and augment our abilities in ways we can scarcely imagine, but, he writes, their potential for danger is simply too high. To avoid these future terrors, McKibben urges us to repeat a single word: enough.

"We need to decide that we live, most of us in the West, long enough. We need to declare, that, in the West, where few of us work ourselves to the bone, we have ease enough. In societies where most of us need storage lockers more than we need nanotech miracle boxes, we need to declare that we have enough stuff. Enough intelligence. Enough capability. Enough."

McKibben is right, of course, that the future of humanity is too important simply to be left to scientists, and the issues involved aren't so complex that laypeople can't participate. Whether or not you believe that certain technologies need to be left unexplored, assuming that's even possible, the ethical issues that surround them are ones that need to be addressed by society.

But McKibben's call for "enough" probably isn't realistic, given humanity's continuing thirst for knowledge. He admits that only authoritarian governments are remotely successful in denying progress.

The persuasiveness of McKibben's case probably depends on the assumptions you hold going in. Few, if any, libertarians will buy his argument that adopting the Amish's reflective views on technology is the key to humanity's survival or appreciate his occasional asides against the free market.

Regardless, McKibben has performed a public service with "Enough" by prodding us to ask crucial questions about the future of humanity that will be taking shape in just a few short years.

• Steven Martinovich is a freelance writer in Sudbury, Ontario.