TIME: Almanac 1993/TIME Almanac 1993.iso/time/080690/0806310.000

Text File | 1992-08-28 | 6.2 KB | 130 lines

                                                                                TECHNOLOGY, Page 64

In Search of Artficial Life


Some scientists believe that things inside their computers are
actually alive. What's really scary is that it may be true

By PHILIP ELMER-DEWITT


    They are born. They live their brief life. The fittest of
them survive long enough to produce offspring. Over time their
descendants evolve, adapting to changes in their environment.
Or they fail to adapt and become extinct. They behave, in
short, just like living things -- except that they are not
flesh and blood but programs that inhabit the memory of a
computer.

    Can something that "lives" inside a computer really be
alive? That is the bizarre question at the heart of
artificial-life research, a fast-growing scientific field that
seeks to illuminate the nature of life by recreating lifelike
behavior in nonliving systems. In laboratories around the
world, scientists tapping at computer keyboards are creating
electronic versions of biological entities -- proteins,
microbes, ants -- that bear a striking resemblance to their
living counterparts. In the process, the researchers are
raising questions that touch on some of biology's most enduring
mysteries: How does nature create order from chaos? How did
life emerge from nonlife? What does it mean to be alive?

    The most notorious computer life-forms are the electronic
viruses that have been injected, inadvertently or maliciously,
into computer networks. Like real viruses, these programs are
strings of instructional code that have the ability to infect
a host computer and reproduce without restraint, sometimes
causing considerable damage. But computer viruses are not
really alive. They do not evolve or metabolize. And they are
created, fully formed, by human programmers. The proponents of
artificial life want their life-forms to create themselves, to
emerge from nonliving components just as life on earth arose
from the primordial ooze.

    Nobody claims to have created true artificial life -- yet.
But some have come intriguingly close. Christopher Langton, a
researcher at New Mexico's Los Alamos National Laboratory, gets
credit for coining the term artificial life. He was fiddling
in the mid-'80s with programs known as cellular automata when
he stumbled on a loop-shaped figure that could spontaneously
reproduce itself. "That was a watershed," he says. "If you
could capture self-reproduction, what else could you do?"

    Today hundreds of people are exploring that question. At
Bellcore, the research affiliate of the Bell telephone
companies, David Ackley makes little creatures with humanoid
faces that roam around a computer-simulated world consuming
resources, evading predators and multiplying like rabbits. At
UCLA David Jefferson and Robert Collins have created colonies
of randomly generated "ants" that over many generations evolve
the ability to navigate electronic mazes and search for symbols
representing food.

    Not all artificial life-forms are confined to a computer
screen. At M.I.T.'s mobile robot lab (also known as the
"artificial insect lab"), Rodney Brooks is building tiny
six-legged creatures that are controlled by interconnected
computer chips and that display behavior (scurrying for cover,
stalking prey) that seems quite purposeful.

    Are these things alive? That depends on how the term is
defined. Surprisingly, there is no clear definition of "life."
Most of the criteria put forward in the past are
anthropocentric. Life on earth is carbon-based and built around
the nucleic acids RNA and DNA, but that may be a historical
accident. Most living things metabolize and multiply, but not
all. Viruses have no metabolisms of their own; mules cannot
reproduce. Many living things grow, but so do clouds and
garbage dumps.

    Still, most people have an intuitive sense of what it means
to be alive. They know life when they see it. That is what is
so disturbing about a good computer simulation. Take Craig
Reynolds' flocking birds. By specifying a couple of simple
rules -- keep a few wings' distance from your neighbors, try
to fly as fast as they do -- Reynolds, a computer scientist at
Symbolics, Inc., got bird-shaped objects on a screen to exhibit
a flocking behavior that is absolutely convincing. The birds
are artificial, but the flocking is real.

    It is the same with life in general. Contends Langton:
"Artificial life will be genuine life. It will simply be made
of different stuff." This is the leap of faith made by a
growing number of scientists, many of whom are associated with
the Sante Fe Institute, a research facility that is the center
of the artificial-life movement. "They feel like they are
taking the first step into taboo territory," says Steven Levy,
a New York City-based author who is writing a book on
artificial life. "It's almost a religion."

    Like religion, artificial life has evolved certain tenets.
One is that lifelike behavior cannot be imposed from the top
down. Rather, it emerges from the bottom up, like flocking
among birds, when large numbers of parts obey a few simple
rules. Another principle, derived from recent advances in the
theory of chaos, is that when a system is sufficiently complex
-- like the mix of chemicals in the primordial sea -- a
lifelike order will spontaneously emerge.

    Scientists have begun to think of possible uses for
adaptive, self-replicating machines -- cleaning up toxic
wastes, perhaps, or exploring outer space. There is a danger,
though, that such machines could multiply uncontrollably, like
the viruses that have disrupted computer networks. Doyne
Farmer, a physicist at the Los Alamos lab, points to a
cautionary science-fiction tale by Stanislaw Lem. In Lem's
Fiasco, space explorers discover a Saturn-like planet with a
ring around it. On closer inspection, the ring turns out to be
a swarm of attack satellites and killer robots, part of a "star
wars" defense shield that had reproduced itself over and over
again. Artificial life, says Farmer, could turn out to be man's
most beautiful creation. Or, like Lem's swarming robots, it
could be a nightmare.