The Age of Spiritual Machines: When Computers Exceed Human Intelligence is a non-fiction book by inventor and futurist Ray Kurzweil about artificial intelligence and the future course of humanity. First published in hardcover on January 1, 1999, by Viking, it has received attention from The New York Times, The New York Review of Books and The Atlantic. In the book Kurzweil outlines his vision for how technology will progress during the 21st century.
Kurzweil believes evolution provides evidence that humans will one day create machines more intelligent than they are. He presents his law of accelerating returns to explain why "key events" happen more frequently as time marches on. It also explains why the computational capacity of computers is increasing exponentially. Kurzweil writes that this increase is one ingredient in the creation of artificial intelligence; the others are automatic knowledge acquisition and algorithms like recursion, neural networks, and genetic algorithms.
Kurzweil predicts machines with human-level intelligence will be available from affordable computing devices within a couple of decades, revolutionizing most aspects of life. He says nanotechnology will augment our bodies and cure cancer even as humans connect to computers via direct neural interfaces or live full-time in virtual reality. Kurzweil predicts the machines "will appear to have their own free will" and even "spiritual experiences". He says humans will essentially live forever as humanity and its machinery become one and the same. He predicts that intelligence will expand outward from Earth until it grows powerful enough to influence the fate of the universe.
Reviewers appreciated Kurzweil's track record with predictions, his ability to extrapolate technology trends, and his clear explanations. However, there was disagreement on whether computers will one day be conscious. Philosophers John Searle and Colin McGinn insist that computation alone cannot possibly create a conscious machine. Searle deploys a variant of his well-known Chinese room argument, this time tailored to computers playing chess, a topic Kurzweil covers. Searle writes that computers can only manipulate symbols which are meaningless to them, an assertion which if true subverts much of the vision of the book.
Background
Ray Kurzweil is an inventor and serial entrepreneur. When The Age of Spiritual Machines was published he had already started four companies: Kurzweil Computer Products, Inc. which created optical character recognition and image scanning technology to assist the blind, Kurzweil Music Systems, which developed music synthesizers with high quality emulation of real instruments, Kurzweil Applied Intelligence, which created speech recognition technology, and Kurzweil Educational Systems, which made print-to-speech reading technology. Critics say predictions from his previous book The Age of Intelligent Machines "have largely come true" and "anticipated with uncanny accuracy most of the key computer developments" of the 1990s. After this book was published he went on to expand upon its ideas in a follow-on book The Singularity is Near. Today Ray Kurzweil works at Google where he is attempting to "create a truly useful AI [artificial intelligence] that will make all of us smarter".
Content
Law of accelerating returns Kurzweil opens by explaining that the frequency of universe-wide events has been slowing down since the Big Bang while evolution has been reaching important milestones at an ever-increasing pace. This is not a paradox, he writes, entropy (disorder) is increasing overall, but local pockets of increasing order are flourishing. Kurzweil explains how biological evolution leads to technology which leads to computation which leads to Moore's law.
Kurzweil unveils several laws of his own related to this progression, leading up to his law of accelerating returns which says time speeds up as order increases. He believes Moore's law will end "by the year 2020" but that the law of accelerating returns mandates progress will continue to accelerate, therefore some replacement technology will be discovered or perfected to carry on the exponential growth.
As in The Age of Intelligent Machines Kurzweil argues here that evolution has an intelligence quotient just slightly greater than zero. He says it is not higher than that because evolution operates so slowly, and intelligence is a function of time. Kurzweil explains that humans are far more intelligent than evolution, based on what we have created in the last few thousand years, and that in turn our creations will soon be more intelligent than us. The law of accelerating returns predicts this will happen within decades, Kurzweil reveals.
Philosophy of mind
Kurzweil introduces several thought experiments related to brain implants and brain scanning; he concludes we are not a collection of atoms, instead we are a pattern which can manifest itself in different mediums at different times. He tackles the mystery of how self-awareness and consciousness can arise from mere matter, but without resolution. Based partly on his Unitarian religious education Kurzweil feels "all of these views are correct when viewed together, but insufficient when viewed one at a time" while at the same time admitting this is "contradictory and makes little sense".
Kurzweil defines the spiritual experience as "a feeling of transcending one's everyday physical and mortal bounds to sense a deeper reality". He elaborates that "just being—experiencing, being conscious—is spiritual, and reflects the essence of spirituality". In the future, Kurzweil believes, computers will "claim to be conscious, and thus to be spiritual" and concludes "twenty-first-century machines" will go to church, meditate, and pray to connect with this spirituality.
Artificial intelligence
Kurzweil says Alan Turing's 1950 paper Computing Machinery and Intelligence launched the field of artificial intelligence. He admits that early progress in the field led to wild predictions of future successes which did not materialize. Kurzweil feels intelligence is the "ability to use optimally limited resources" to achieve goals. He contrasts recursive solutions with neural nets, he likes both but specifically mentions how valuable neural nets are since they destroy information during processing, which if done selectively is essential to making sense of real-world data. A neuron either fires or not "reducing the babble of its inputs to a single bit". He also greatly admires genetic algorithms which mimic biological evolution to great effect.
Recursion, neural nets and genetic algorithms are all components of intelligent machines, Kurzweil explains. Beyond algorithms Kurzweil says the machines will also need knowledge. The emergent techniques, neural nets and genetic algorithms, require significant training effort above and beyond creating the initial machinery. While hand-coded knowledge is tedious and brittle acquiring knowledge through language is extremely complex.
Building new brains
To build an artificial brain requires formulas, knowledge and sufficient computational power, explains Kurzweil. He says "by around the year 2020" a $1,000 personal computer will have enough speed and memory to match the human brain, based on the law of accelerating returns and his own estimates of the computational speed and memory capacity of the brain. Kurzweil predicts Moore's law will last until 2020 so current integrated circuits should come close to human brain levels of computation, but he says three dimensional chips will be the next big technology, followed potentially by optical computing, DNA computing, nanotubes, or quantum computing.
Kurzweil feels the best model for an artificial brain is a real human brain, and suggests slicing up and digitizing preserved human brains or examining them non-invasively as technology permits. Kurzweil differentiates between scanning the brain to understand it, in a generic fashion, and scanning a particular person's brain in order to preserve it in exact detail, for "uploading" into a computer for example. The latter is much harder to do, he notes, because it requires capturing much more detail, but it will eventually happen as well. When it does "we will be software, not hardware" and our mortality will become a function of our ability to "make frequent backups".
Building new bodies
Kurzweil notes that many thoughts people have are related to their bodies, and reassures that he does not believe in creating a disembodied brain. He reviews all the various body implants that existed when the book was published, explaining that our bodies are already becoming more synthetic over time. Kurzweil says this trend will continue and that the technology will advance from macroscopic implants, to cellular sized insertions, and finally to nanotechnology.
Nanotechnology has the potential to reshape the entire world, Kurzweil exclaims. Assembling materials molecule by molecule could solve energy problems, cure cancer and other diseases, strengthen our bodies, and produce self-assembling food, clothing, and buildings. Kurzweil admits that nanotechnology carries a big risk; a self-replicating substance, without the constraints of a living organism, might grow out of control and consume everything. However he points out that today there are already technologies which pose grave risks, for example nuclear power or weapons, and we have managed to keep them relatively safe, so he feels we can probably do the same with nanotechnology.
Finally Kurzweil says there is the prospect of virtual bodies, where direct neural implants would give us the sensation of having bodies and a way to exert control, without any physical manifestation at all. Although he quickly brings things back to nanotechnology by pointing out that sufficiently advanced nanotechnology will be like having a virtual world, since "utility fog" will appear to be entirely absent and then instantly morph into functional physical shapes. Kurzweil broaches the topic of sex in futuristic times, reminding us that every new technology "adopts sexual themes". Kurzweil envisions virtual sex, sexbots, and as well as more chaste activities like strolling along a "virtual Cancún beach".
State of the art
Kurzweil explains that in 1999 computers are essential to most facets of life, yet he predicts no major disruption related to the then-pending Y2K problem. He says computers are narrow-minded and brittle so far, but suggests in specific domains they are showing signs of intelligence. As examples Kurzweil cites computer-generated or assisted music, and tools for the automatic or semi-automatic production of literature or poetry. He shows examples of paintings by AARON as programmed by Harold Cohen which can be automatically created. Kurzweil reviews some of his predictions from The Age of Intelligent Machines and various past presentations, and is very pleased with his record. Finally he predicts a new Luddite movement as intelligent machines take away jobs, although he predicts a net gain of new and better jobs.
Predictions
Kurzweil has a dense chapter of predictions for each of these years: 2009, 2019, 2029, 2099. For example, when discussing the year 2009 he makes many separate predictions related to computer hardware, education, people with disabilities, communication, business and economics, politics and society, the arts, warfare, health and medicine, and philosophy.