This is part of IEEE Spectrum's SPECIAL REPORT: THE SINGULARITY
I'm 54, with all that entails. Gray hair, trick knee, trickier memory. I still play a mean game of hockey, and my love life requires no pharmaceutical enhancement. But entropy looms ever larger. Suffice it to say, I would love to believe that we are rapidly approaching ”the singularity.”Like paradise, technological singularity comes in many versions, but most involve bionic brain boosting. At first, we'll become cyborgs, as stupendously powerful brain chips soup up our perception, memory, and intelligence and maybe even eliminate the need for annoying TV remotes. Eventually, we will abandon our flesh-and-blood selves entirely and upload our digitized psyches into computers. We will then dwell happily forever in cyberspace where, to paraphrase Woody Allen, we'll never need to look for a parking space. Sounds good to me!
Notably, singularity enthusiasts tend to be computer specialists, such as the author and retired computer scientist Vernor Vinge, the roboticist Hans Moravec, and the entrepreneur Ray Kurzweil. Intoxicated by the explosive progress of information technologies captured by Moore's Law, such singularitarians foresee a ”merger of biological and nonbiological intelligence,” as Kurzweil puts it, that will culminate in ”immortal software-based humans.” It will happen not within a millennium, or a century, but no later than 2030, according to Vinge. These guys--and, yes, they're all men--are serious. Kurzweil says he has adopted an antiaging regimen so that he'll ”live long enough to live forever.”
Specialists in real rather than artificial brains find such bionic convergence scenarios naive, often laughably so. Gerald Edelman, a Nobel laureate and director of the Neurosciences Institute, in San Diego, says singularitarians vastly underestimate the brain's complexity. Not only is each brain unique, but each also constantly changes in response to new experiences. Stimulate a brain with exactly the same input, Edelman notes, and you'll never see the same signal set twice in response.
”This is a wonderful project--that we're going to have a spiritual bar mitzvah in some galaxy,” Edelman says of the singularity. ”But it's a very unlikely idea.”
Neuroscience is indeed thriving. Membership in the Society for Neuroscience has surged from 500, when it was founded in Washington, D.C., in 1970, to almost 40 000 today. New brain journals seem to spring up daily, crammed with data from ever-more-powerful brain probes such as magnetic-resonance imaging and transcranial magnetic stimulation. In addition to such noninvasive methods, scientists can stick electrodes in brains to monitor and stimulate individual neurons. Researchers are also devising electrode-based ”neural prostheses” to help people with nervous-system disorders such as deafness, blindness, paralysis, and memory loss.
In spite of all those advances, neuroscientists still do not understand at all how a brain (the squishy agglomeration of tissue and neurons) makes a conscious mind (the intangible entity that enables you to fall in love, find irony in a novel, and appreciate the elegance of a circuit design). ”No one has the foggiest notion,” says the neuroscientist Eric Kandel of Columbia University Medical Center, in New York City. ”At the moment all you can get are informed, intelligent opinions.” Neuroscientists lack an overarching, unifying theory to make sense of their sprawling and disjointed findings, such as Kandel's Nobel Prize–winning discovery of the chemical and genetic processes that underpin memory formation in sea slugs.
The brain, it seems, is complex enough to conjure fantasies of technotranscendence and also to foil their fulfillment.
A healthy adult brain contains about 100 billion nerve cells, or neurons. A single neuron can be linked via axons (output wires) and dendrites (input wires) across synapses (gaps between axons and dendrites) to as many as 100 000 other neurons. Crank the numbers and you find that a typical human brain has quadrillions of connections among its neurons. A quadrillion is a one followed by 15 zeroes; a stack of a quadrillion U.S. pennies would go from the sun out past the orbit of Jupiter.
Adding to the complexity, synaptic connections constantly form, strengthen, weaken, and dissolve. Old neurons die and--evidence now indicates, overturning decades of dogma--new ones are born.
Far from being stamped from a common mold, neurons display an astounding variety of forms and functions. Researchers have discovered scores of distinct types just in the optical system. Neurotransmitters, which carry signals across the synapse between two neurons, also come in many different varieties. In addition to neurotransmitters, neural-growth factors, hormones, and other chemicals ebb and flow through the brain, modulating cognition in ways both profound and subtle.
Indeed, the more you learn about brains, the more you may wonder how the damn things work. And in fact, sometimes they don't. They succumb to schizophrenia, bipolar disorder, depression, Alzheimer's disease, and many other disorders that resist explanation and treatment.
Nevertheless, the brain is a computer, singularitarians insist. It just has an extremely messy wiring diagram. According to this perspective, neurons resemble transistors, absorbing, processing, and reemitting the electrochemical pulses known as action potentials. With an amplitude of one-tenth of a volt and a duration of one millisecond, action potentials are remarkably uniform, and they do not dissipate even when zipping down axons a meter long (yes, a full meter). Also called spikes, to reflect their appearance on oscilloscopes, action potentials supposedly serve as the brain's basic units of information.
Within a decade or so, computers will surpass the computational power of brains, many singularitarians say. They base this claim on the assumption that those spikes represent the brain's total computational capacity. If the brain contains one quadrillion synapses processing on average 10 action potentials per second, then the brain performs 10 quadrillion operations per second. At some point in the near future, some singularitarians say, computers will surpass that processing rate and leave us in their cognitive dust unless we embrace them through bionic convergence or uploading.
We've heard such prophesies before. A half century ago, artificial-intelligence pioneers such as Marvin Minsky of MIT and Herbert Simon of Carnegie Mellon University predicted that computers would exceed human intelligence within a generation. Their prophesies inspired sci-fi writers like Arthur C. Clarke--creator of the cybervillain HAL--as well as younger AI visionaries like Kurzweil, Moravec, and Vinge.
But even Minsky admits that computers are still idiot savants. ”I wish I could tell you that we have intelligent machines, but we don't,” he says. The world's most powerful computers, he acknowledges, lack the common sense of a toddler; they can't even distinguish cats from dogs unless they are explicitly and painstakingly programmed to do so.
Nevertheless, singularitarians are quite right that, if current trends continue, supercomputers will exceed 10 quadrillion operations per second within a decade. IBM's Blue Gene/P supercomputer, introduced nearly a year ago, can be configured to process up to 3 quadrillion operations per second, although no customer has yet ordered one with the full complement of 884 736 processors that would be needed to get that kind of a processing rate. Argonne National Laboratory, in Illinois, is now completing the upgrade of a Blue Gene/P that should be good for around half a quadrillion operations per second.