Markkula Center of Applied Ethics

The Age of Spiritual Machines

By Ray Kurzweil
Viking Press (1999)
reviewed by Neil Quinn

You’ve had a rotten day. All you want is to go home and get a little sympathy, but your spouse just shrugs off your troubles and suggests how you might do things differently so that your woes won’t return. This is not the understanding you had in mind.

Cheer up. If Ray Kurzweil, author of The Age of Spiritual Machines, is right, in a few years you may be able to commiserate with the very person who understands you best: you (albeit in a silicon-based life form).

Extrapolating from the history of computing (very systematically presented in The Age of Spiritual Machines), Kurzweil predicts that silicon-based life forms with the thinking capacity of humans should start arriving on the scene around 2029. This estimate is based on Kurzweil’s theory of "time and chaos," which suggests that evolutionary time is accelerating.

It took evolution 4 billion years to create the first human being, but, Kurzweil writes, "humans will have vastly beaten evolution…, achieving in a matter of only thousands of years as much or more than evolution achieved in billions of years. So human intelligence, a product of evolution, is far more intelligent than its creator."

And machine intelligence, a product of human design, will be far more intelligent than its creator. The author demonstrates that humans have devised a computational technology that has roughly doubled in capability every three years for the past 100 years. This pattern is remarkably similar to Moore’s Law, named after Gordon Moore, the founder of Intel Corp. Moore’s Law states that the density of transistors on a silicon chip doubles every two years. If this trend continues, we can make some remarkable predictions:

Today’s desktop computer, which can be purchased for roughly $1,000, has the computing capacity of a small insect brain. In 10 years, Kurzweil writes, that same $1,000 should purchase a computer with the capacity of a mouse brain. Twenty years later, $1,000 will purchase a computer with the capacity of the human brain. Thirty years after that, $1,000 will purchase a computer with roughly the capacity of all the brains in the human race.

Eventually, Kurzweil predicts, the computer will be able to create "its own next generation without human intervention." Once this occurs, the pace of technological evolution will leave us humans in the dust.

Of course, this extrapolation says nothing about whether these computers will take on human characteristics. However, the author theorizes that the increase in computational capability will allow us to scan our human brain using MRI technology and download that information into a computer. This computer, Kurzweil claims, will have human intelligence and emotion.

Kurzweil’s MRI scenario suggests that eventually we may become an inseparable meld of human and machine. If that occurs, how will we define death? Will it be when our human bodies are no longer functioning, or will it be when the machine portion of us breaks down? Or will there be any such thing as death, in the sense that our minds can continue on in a silicon-based form?

Although these questions may seem far out in 2000, we need to begin considering them now so that we will be prepared to address the ethical ramifications when the time comes. One can certainly argue with Kurzweil’s timeline for machine evolution, but the day will arrive when a very inexpensive computer will have all of the intelligence and emotion that human beings exhibit.

And there’s the ethical rub. What will be our moral responsibility toward these machines? Will we be required to treat them as we do humans? Or will we simply unplug them when we tire of them?

Kurzweil’s answer is clear in the title of his book: The Age of Spiritual Machines.. "Just being—experiencing, being conscious—is spiritual and reflects the essence of spirituality," he writes.

Machines, derived from human thinking and surpassing humans in their capacity for experience, will claim to be conscious, and thus be spiritual. They will believe that they are conscious. They will believe that they have spiritual experiences. They will be convinced that these experiences are meaningful. And given the historical inclination of the human race to anthropomorphize the phenomena we encounter, and the persuasiveness of the machines, we’re likely to believe them when they tell us this.


Neil Quinn is the director of Technology and Ethics at the Markkula Center for Applied Ethics and works for the Center for Science, Technology, and Society. His review was inspired by discussions of The Age of Spiritual Machines among members of the Ethics Center’s technology reading group, which brings faculty and staff together to discuss the moral implications of technological advances.