The Age of Spiritual Machines: When Computers Exceed Human Intelligence
by Ray Kurzweil Viking: 1998. 376 pp. $25.95, £15.69
Robot: Mere Machine to Transcendent Mind
by Hans Moravec Oxford University Press: 1998. 220 pp. $25, £15.12
CORBIS/BETTMANN
Man made machine:
super-intelligent robots 'will
be our heirs, sharing our goals
and values'.
According to evolutionary biologists and palaeontologists, about 99
per cent of all species that have ever inhabited the Earth are now
extinct. If you believe the thesis of these two books, Homo sapiens'
day in the sun as the leading intellectual force on this planet is
also just about over. In fact, Kurzweil and Moravec both turn out the
light for humans somewhere in the middle of the twenty-first century,
at what Kurzweil would call the "dawning of the age of spiritual
machines''.
Kurzweil, one of the great innovators in computing technology,
predicts that computers exceeding the memory capacity and
computational power of the human brain will be available within the
next 20 years. In the scenario sketched out in The Age of Spiritual
Machines, well before the year 2050, information will be fed directly
into our brains via neural connections with machines, and the
distinction between humans and machines will be totally blurred. At
that point, computers will have acquired consciousness, human-style,
and will embark on an evolutionary pathway that diverges from our own
in almost every way that counts -- physically, emotionally and
cognitively.
In the world of artificial intelligence, such behaviour would be
termed 'strong AI'. Kurzweil's vision is the strongest of strong AI
-- with a vengeance. Lest you fear that machines will then just keep
humans around for laughs and/or as pets, Kurzweil predicts that humans
will gradually co-evolve with these machines via neural implants that
enable us to 'upload' our carbon-based neural circuitry into whatever
kind of hardware machines are using in the late twenty-first
century. At this point, there will be no clear distinction between
humans and computers, and life expectancy will no longer be a term
that pertains to intelligent beings. So humans won't exactly
disappear; they will simply merge with the machines. Isn't that
comforting?
The rationale underlying the arguments of both books is what Kurzweil
has termed "The law of accelerating returns'', which applies
specifically to evolutionary processes like the development of
computer technology. Basically, this states that as order
exponentially increases, time exponentially speeds up. In other words,
the time interval between notable events gets shorter as time
passes. The crucial implication is then that the valuable products of
the evolutionary process also accelerate. Since computer technology is
an evolutionary process that builds on its own progress, the time
required to accomplish a fixed objective gets exponentially shorter as
time goes on. So, for instance, it took 90 years for the first million
instructions per second (MIP) to be achieved versus one day for an
additional MIP now. If you buy into this law -- and all empirical
evidence currently available supports it completely -- then the
replacement of humans by machines as the primary intellectual force on
Earth is indeed imminent.
A crucial part of the argument is that the computational process is
evolutionary, so it will not crash into the same kind of barriers
faced by other sorts of exponentially growing processes, such as
Moore's law (which states that the surface area of an integrated
circuit chip is halved every 12 months).
How will computing power continue to accelerate as Moore's law dies
out? According to Kurzweil, it will use the third dimension of space
in semiconductor design -- including circuits that don't generate
heat. And as this technology tops out, others like DNA and quantum
computing will step in to take its place. Thus, the entire
evolutionary process of computing is literally unbounded. So goes
Kurzweil's argument, anyway.
The Moravec volume draws essentially the same conclusions, emphasizing
the emergence of robots embodying the greatly enhanced computing
technology of the twenty-first century. But his vision of the "robotic
takeover'' is not an apocalyptic one; rather, he takes the startling
view that "Intelligent machines, which will grow from us, learn our
skills, and share our goals and values, can be viewed as children of
our minds''. In other words, these super-intelligent robots will be
our heirs, and as such we will want them to outdistance us, much as
parents want their biological heirs to have better, more productive
lives than they have themselves.
Moravec then goes on to argue that these intelligent machines offer us
lowly carbon-based forms the best chance we'll ever get for
immortality by uploading ourselves into advanced robots -- the very
same process that Kurzweil emphasizes. At this point, we will become
our children and live for ever. This is either a science-fiction
nightmare or a utopian fantasy: take your pick. In either case, the
story Moravec weaves is fascinating.
While each of these books tells much the same tale, they do it in very
different ways. Kurzweil's account focuses mostly on the intelligence
of machines and the way humans will interface with them via direct
neural connections to our brains. The writing is always lively and the
arguments are well presented and amplified by numerous boxed cut-outs,
tables and graphs showing the ever-accelerating pace of computing
technology. The Moravec volume, on the other hand, spends a
considerable number of pages on a detailed discussion of the evolution
of robots, before moving on to some of the same types of speculations
about machine intelligence as Kurzweil. The writing is equally lively,
bolstered with diagrams and charts to support the arguments.
I recommend both books to any reader who wants a mind-expanding
account of the rise of the age of intelligent machines. These two
volumes are nothing less than a blueprint for how to shove Homo
sapiens off centre-stage in evolution's endless play.
John L. Casti is at the Santa Fe Institute, 1399 Hyde Park Road, Santa
Fe, New Mexico 87501, USA.
25 February 1999
Nature © Macmillan Publishers Ltd 1999 Registered No. 785998
England.