Thinking about the future can help you shape it. Thinking too much about the future can make you spacey.

By the year 2019, thanks to information technology (IT), humans will have largely overcome the limits of our humanity. We will have found cures for the major diseases that kill 95 percent of us in the developed world. By 2029, we will become godlike—tiny computer chips embedded into our bodies will stop disease and reverse aging, ever expanding our lifespans.

Such are the prognostications of the current pied piper of the digital utopia crowd, Ray Kurzweil (http://www.kurzweilai.net). In a syndicated newspaper feature, he recently shared these and other rosy predictions about the power of IT. His main thesis is that IT doesn’t just lead to linear growth, as humanity has experienced in the past, but exponential growth, and not just with IT.

Kurzweil is the author of such books as The Singularity Is Near: When Humans Transcend Biology , Fantastic Voyage: Live Long Enough to Live Forever, and The Age of Spiritual Machines , and in them he has made other astonishing predictions. My favorite: Human and machine intelligence will merge and become indistinguishable, growing exponentially until we will be able to control how the universe evolves.

It’s easy to dismiss Kurzweil. His background is in speech recognition—a technology that, despite its years of promises, has never crossed into the desktop computing mainstream because of its inability to perform as well as pecking away at a keyboard and pushing around a mouse.

If you do dismiss him, though, you risk looking like a change-averse Luddite. The past is littered with failures of the imagination, even among those deeply involved with IT. Ken Olson, founder and chairman of Digital Equipment Corp., said in 1977, “There is no reason anyone would want a computer in their home.” Thomas Watson, president and CEO of IBM, in 1943 said, “I think there is a world market for maybe five computers.”

Talking about talkies, H. M. Warner, co-founder and president of Warner Brothers, said in 1927, “Who the hell wants to hear actors talk?” According to an 1876 internal Western Union memo, “This ‘telephone’ has too many shortcomings to be seriously considered as a means of communication. The device is inherently of no value to us.”

Kurzweil’s vision of the future is enticing, like a comic book, and he has his followers. Who wouldn’t want to become a Superman or Wonder Woman?

To be fair, computers are indeed amazing machines. PCs allow you to communicate with far more people than a phone or letter. They help you write far more efficiently than a typewriter or pen and paper. They make it possible to keep track of people and things far more easily than a roster or list. They let you budget, forecast, and plan far more effectively than a calculator or table. And they make education far more compelling than words and pictures on paper.

What’s more, unlike just about any other product on the market, personal computers over time decrease in price while they increase in power and ease of use.

Yet what our noggins do far better than today’s fastest supercomputers is “pattern recognition,” allowing us to know faces and appreciate a sunset.

Kurzweil thinks that, a quarter century from today, common computers will have these capabilities and others, including consciousness and the ability to have emotional and even spiritual experiences. I don’t think so.

As littered as the past is with failures of the imagination, it’s equally littered with products of over-excited imaginations. When has the last time you commuted to work in your flying car? What are you doing with all of the free time created by time-saving washing machines, microwave ovens, and other home appliances? How did you enjoy that vacation to the moon?

In his 2001 book, Technoromanticism: Digital Narrative, Holism, and theRomance of the Real , Richard Coyne discusses the romanticization of digital technology, contrasting it with rationalism and pragmatism.

Technorealism is the name that has been coined for thinking critically about the role that IT plays in society and history. At the Technorealism Web site (http://www.technorealism.org), you can read about its principles.

Sure, think about the future. Plan how to get where you want to go and what to do if the unexpected arises. But be careful about what you say about tomorrow. It’s a slippery place. As Lao Tzu said in the 6th century B.C., “Those who have knowledge, don’t predict. Those who predict, don’t have knowledge.”