by Paul Davies
The Atlantic Monthly
Summary: The discovery of just a single bacterium somewhere beyond
Earth would force us to revise our understanding of who we are and
where we fit into the cosmic scheme of things, throwing us into a
deep spiritual identity crisis that would be every bit as dramatic
as the one Copernicus brought about in the early 1500s, when he
asserted that Earth was not at the center of the universe.
The recent discovery of abundant water on Mars, albeit in the form
of permafrost, has raised hopes for finding traces of life there.
The Red Planet has long been a favorite location for those
speculating about extraterrestrial life, especially since the 1890s,
when H. G. Wells wrote The War of the Worlds and the American
astronomer Percival Lowell claimed that he could see artificial
canals etched into the planet’s parched surface. Today, of course,
scientists expect to find no more than simple bacteria dwelling deep
underground, if even that. Still, the discovery of just a single
bacterium somewhere beyond Earth would force us to revise our
understanding of who we are and where we fit into the cosmic scheme
of things, throwing us into a deep spiritual identity crisis that
would be every bit as dramatic as the one Copernicus brought about
in the early 1500s, when he asserted that Earth was not at the
center of the universe.
Whether or not we are alone is one of the great existential
questions that confront us today. Probably because of the high
emotional stakes, the search for life beyond Earth is deeply
fascinating to the public. Opinion polls and Web-site hits indicate
strong support for and interest in space missions that are linked
even obliquely to this search. Perceiving the public’s interest,
NASA has reconfigured its research strategy and founded the
Astrobiology Institute, dedicated to the study of life in the
cosmos. At the top of the agenda, naturally, is the race to find
life elsewhere in the solar system.
Researchers have long focused on
Mars in their search for
extraterrestrial life because of its relative proximity. But
twenty-five years ago, as a result of the 1976 Viking mission, many
of them became discouraged. A pair of spacecraft had passed through
the planet’s extremely thin atmosphere, touched down on the surface,
and found it to be a freeze-dried desert drenched with deadly
ultraviolet rays. The spacecraft, equipped with robotic arms,
scooped up Martian dirt so that it could be examined for signs of
biological activity. The results of the analysis were inconclusive
but generally negative, and hopes faded for finding even simple
microbes on the surface of Mars.
The outlook today is more optimistic. Several probes are scheduled
to visit Mars in the coming months, and all will be searching for
signs of life. This renewed interest is due in part to the discovery
of organisms living in some remarkably hostile environments on Earth
(which opens up the possibility of life on Mars in places the
probes didn’t examine), and in part to better information about the
planet’s ancient history. Scientists now believe that Mars once had
a much thicker atmosphere, higher temperatures, rivers, floods, and
extensive volcanic activity—all conditions considered favorable to
the emergence of life.
The prospects for finding living organisms on Mars remain slim, of
course, but even
traces of past life would represent a discovery of
unprecedented scientific value. Before any sweeping philosophical or
theological conclusions could be drawn, however, it would be
necessary to determine whether this life was the product of a second
genesis—that is, whether its origin was independent of life on
Earth. Earth and Mars are known to trade material in the form of
rocks blasted from the planets’ surfaces by the violent impacts of
asteroids and comets. Microbes could have hitched a ride on this
detritus, raising the possibility that life started on Earth and was
transferred to Mars, or vice versa. If traces of past life were
discovered on Mars but found to be identical to some form of
terrestrial life, transportation by ejected rocks would be the most
plausible explanation, and we would still lack evidence that life
had started from scratch in two separate locations.
The significance of this point is crucial. In his theory of
Charles Darwin provided a persuasive account of how life
evolved over billions of years, but he pointedly omitted any
explanation of how life got started in the first place. "One might
as well think of origin of matter," he wrote in a letter to a
friend. A century and a half later, scientists still have little
understanding of how the first living thing came to be.
Some scientists believe that life on Earth is a freak accident of
chemistry, and as such must be unique. Because even the simplest
known microbe is breathtakingly complex, they argue, the chances
that one formed by blind molecular shuffling are infinitesimal; the
probability that the process would occur twice, in separate
locations, is virtually negligible. The French biochemist and Nobel
laureate Jacques Monod was a firm believer in this view.
last knows he is alone in the unfeeling immensity of the universe,
out of which he has emerged only by chance," he wrote in 1971.
used this bleak assessment as a springboard to argue for atheism and
the absurdity and pointlessness of existence. As Monod saw it, we
are merely chemical extras in a majestic but impersonal cosmic
drama—an irrelevant, unintended sideshow.
But suppose that’s not what happened. Many scientists believe
life is not a freakish phenomenon (the odds of life’s starting by
chance, the British cosmologist Fred Hoyle once suggested, are
comparable to the odds of a whirlwind’s blowing through a junkyard
and assembling a functioning Boeing 747) but instead is written into
the laws of nature. "The universe must in some sense have known we
were coming," the physicist Freeman Dyson famously observed. No one
can say precisely in what sense the universe might be pregnant with
life, or how the general expectancy Dyson spoke of might translate
into specific physical processes at the molecular level. Perhaps
matter and energy always get fast-tracked along the road to life by
what’s often called "self-organization." Or perhaps the power of
Darwinian evolution is somehow harnessed at a pre-biotic molecular
stage. Or maybe some efficient and as yet unidentified physical
process (quantum mechanics?) sets the gears in motion, with organic
life as we know it taking over the essential machinery at a later
Under any of these scenarios life becomes a fundamental
rather than an incidental product of nature. In 1994, reflecting on
this same point, another Nobel laureate, the Belgian biochemist
Christian de Duve, wrote,
"I view this
universe not as a ’cosmic
joke,’ but as a meaningful entity—made in such a way as to generate
life and mind, bound to give birth to thinking beings able to
discern truth, apprehend beauty, feel love, yearn after goodness,
define evil, experience mystery."
Absent from these accounts is any mention of miracles. Ascribing the
origin of life to a divine miracle not only is anathema to
scientists but also is theologically suspect. The term "God of the
gaps" was coined to deride the notion that God can be invoked as an
explanation whenever scientists have gaps in their understanding.
The trouble with invoking God in this way is that as science
advances, the gaps close, and God gets progressively squeezed out of
the story of nature. Theologians long ago accepted that they would
forever be fighting a rearguard battle if they tried to challenge
science on its own ground. Using the formation of life to prove the
existence of God is a tactic that risks instant demolition should
someone succeed in making life in a test tube. And the idea that God
acts in fits and starts, moving atoms around on odd occasions in
competition with natural forces, is a decidedly uninspiring image of
the Grand Architect.
The theological battle line in relation to the formation of life is
not, therefore, between the natural and the miraculous but between
sheer chance and lawlike certitude. Atheists tend to take the first
side, and theists line up behind the second; but these divisions are
general and by no means absolute. It’s perfectly possible to be an
atheist and believe that life is built ingeniously into the nature
of the universe. It’s also possible to be a theist and suppose that
God engineered just one planet with life, with or without the help
Though the discovery of microbes on Mars or elsewhere would ignite a
passionate theological debate, the truly difficult issues surround
the prospect of advanced alien beings in possession of intelligence
and technology. Most scientists don’t think that such beings exist,
but for forty years a dedicated band of astronomers has been
sweeping the skies with radio telescopes in hopes of finding a
message from a civilization elsewhere in the galaxy. Their project
is known as SETI (Search for Extraterrestrial Intelligence).
Because our solar system is relatively young compared with the
universe overall, any alien civilization the SETI researchers might
discover is likely to be much older, and presumably wiser, than
ours. Indeed, it might have achieved our level of science and
technology millions or even billions of years ago. Just
contemplating the possibility of such advanced extraterrestrials
appears to raise additional uncomfortable questions for religion.
The world’s main faiths were all founded in the pre-scientific era,
when Earth was widely believed to be at the center of the universe
and humankind at the pinnacle of creation. As scientific discoveries
have piled up over the past 500 years, our status has been
incrementally diminished. First Earth was shown to be
planet of several orbiting the Sun. Then the solar system itself was
relegated to the outer suburbs of the galaxy, and the Sun classified
as an insignificant dwarf star among billions. The theory of
evolution proposed that human beings occupied just a
small branch on
a complex evolutionary tree. This pattern continued into the
twentieth century, when the supremacy of our much vaunted
intelligence came under threat. Computers began to outsmart us. Now
genetic engineering has raised the specter of designer babies with
superintellects that leave ours far behind. And we must consider the
uncomfortable possibility that in astrobiological terms,
children may be galactic also - rans.
Theologians are used to putting a brave face on such developments.
Over the centuries the Christian church, for example, has time and
again been forced to accommodate new scientific facts that
existing doctrine. But these accommodations have usually been made
reluctantly and very belatedly. Only recently, for example, did
Pope acknowledge that Darwinian evolution is more than just a
theory. If SETI succeeds, theologians will not have the luxury of
decades of careful deliberation to assess the significance of the
discovery. The impact will be instant.
The discovery of alien superbeings might not be so corrosive to
religion if human beings could still claim special spiritual status.
After all, religion is concerned primarily with people’s
relationship to God, rather than with their biological or
intellectual qualities. It is possible to imagine alien beings who
are smarter and wiser than we are but who are spiritually inferior,
or just plain evil. However, it is more likely that any civilization
that had surpassed us scientifically would have improved on our
level of moral development, too. One may even speculate that an
advanced alien society would sooner or later find some way to
genetically eliminate evil behavior, resulting in a race of saintly
Suppose, then, that E.T. is far ahead of us not only scientifically
and technologically but spiritually, too. Where does that leave
mankind’s presumed special relationship with God? This conundrum
poses a particular difficulty for Christians, because of the unique
nature of the Incarnation. Of all the world’s major religions,
Christianity is the most species-specific. Jesus Christ was
humanity’s savior and redeemer. He did not die for the dolphins or
the gorillas, and certainly not for the proverbial little green men.
But what of deeply spiritual aliens? Are they not to be saved? Can
we contemplate a universe that contains perhaps a trillion worlds of
saintly beings, but in which the only beings eligible for salvation
inhabit a planet where murder, rape, and other evils remain rife?
Those few Christian theologians who have addressed this thorny issue
divide into two camps. Some posit multiple incarnations and even
multiple crucifixions—God taking on little green flesh to save
little green men, as a prominent Anglican minister once told me. But
most are appalled by this idea or find it ludicrous. After all, in
the Christian view of the world, Jesus was God’s only son. Would
have the same person born, killed, and resurrected in endless
succession on planet after planet? This scenario was lampooned as
long ago as 1794, by Thomas Paine.
"The Son of God," he wrote in
Age of Reason, "and sometimes God himself, would have nothing else
to do than to travel from world to world, in an endless succession
of death, with scarcely a momentary interval of life."
Paine went on
to argue that Christianity was simply incompatible with the
existence of extraterrestrial beings, writing, "He who thinks he
believes in both has thought but little of either."
Catholics tend to regard the idea of multiple incarnations as
verging on heresy, not because of its somewhat comic aspect but
because it would seem to automate an act that is supposed to be
God’s singular gift. "God chose a very specific way to redeem human
beings," writes George Coyne, a
Jesuit priest and the director of
the Vatican Observatory, whose own research includes astrobiology.
"He sent his only son,
Jesus, to them, and Jesus gave up his life so
that human beings would be saved from their sin. Did God do this for
extraterrestrials? ... The theological implications about God are
getting ever more serious."
Paul Tillich, one of the few prominent Protestant theologians to
give serious consideration to the issue of alien beings, took a more
"Man cannot claim to occupy the only possible place
for incarnation," he wrote.
The Lutheran theologian
Ted Peters, of
the Center for Theology and the Natural Sciences, in Berkeley,
California, has made a special study of the impact on religious
faith of belief in extraterrestrials. In discussing the tradition of
debate on this topic, he writes,
"Christian theologians have
routinely found ways to address the issue of Jesus Christ as
incarnate and to conceive of God’s creative power and saving power
exerted in other worlds."
Peters believes that Christianity is
robust enough and flexible enough to accommodate the discovery of
extraterrestrial intelligence, or ETI. One theologian who is
emphatically not afraid of that challenge is Robert Russell, also of
the Center for Theology and the Natural Sciences.
"As we await ’first contact,’" he has written, "pursuing these kinds of questions
and reflections will be immensely valuable."
Clearly, there is considerable diversity—one might even say
muddle—on this topic in theological circles. Ernan McMullin, a
professor emeritus of philosophy at Notre Dame University, affirms
that the central difficulty stems from Christianity’s roots in a
"It was easier to accept the idea of
becoming man," he has written, "when humans and their abode both
held a unique place in the universe."
He acknowledges that
Christians especially face a stark predicament in relation to
but feels that Thomas Paine and his like-minded successors have
presented the problem too simplistically. Pointing out that concepts
such as original sin, incarnation, and salvation are open to a
variety of interpretations, McMullin concludes that there is also
widespread divergence among Christians on the correct response to
the ETI challenge. On the matter of multiple incarnations he writes,
"Their answers could range ... from
’yes, certainly’ to ’certainly
not.’ My own preference would be a cautious ’maybe.’"
Even for those Christians who
dismiss the idea of multiple
incarnations there is an interesting fallback position: perhaps the
course of evolution has an element of directionality, with humanlike
beings the inevitable end product. Even if Homo sapiens as such may
not be the unique focus of God’s attention, the broader class of all
humanlike beings in the universe might be. This is the basic idea
espoused by the philosopher Michael Ruse, an ardent Darwinian and an
agnostic sympathetic to Christianity. He sees the incremental
progress of natural evolution as God’s chosen mode of creation, and
the history of life as a ladder that leads inexorably from microbes
Most biologists regard a "progressive evolution," with human beings
its implied preordained goal, as preposterous. Stephen Jay Gould
once described the very notion as "noxious." After all, the
of Darwinism is that nature is blind. It cannot look ahead.
chance is the driving force of evolution, and randomness by
definition has no directionality. Gould insisted that if the
evolutionary tape were replayed, the result would be very different
from what we now observe. Probably life would never get beyond
microbes next time around....
But some respected biologists disagree sharply with Gould on this
point. Christian de Duve does not deny that the fine details of
evolutionary history depend on happenstance, but he believes that
the broad thrust of evolutionary change is somehow innately
predetermined—that plants and animals were almost destined to emerge
amid a general advance in complexity. Another Darwinian biologist,
Simon Conway Morris, of Cambridge University, makes his own case for
a "ladder of progress," invoking the phenomenon of convergent
evolution—the tendency of similar-looking organisms to evolve
independently in similar ecological niches. For example, the
Tasmanian tiger (now extinct) played the role of the big cat in
Australia even though, as a marsupial, it was genetically far
removed from placental mammals. Like Ruse, Conway Morris maintains
that the "humanlike niche" is likely to be filled on
that have advanced life. He even goes so far as to argue that
extraterrestrials would have a humanoid form. It is not a great leap
from this conclusion to the belief that extraterrestrials would sin,
have consciences, struggle with ethical questions, and fear death.
The theological difficulties posed by the possibility of advanced
alien beings are less acute for Judaism and
Islam. Muslims, at
least, are prepared for ETI: the Koran states explicitly,
His Signs is the creation of the heavens and the earth, and the
living creatures that He has scattered through them."
both religions stress the specialness of human beings—and, indeed,
of specific, well-defined groups who have been received into the
faith. Could an alien become a Jew or a Muslim? Does the concept
even make sense? Among the major religious communities, Buddhists
and Hindus would seem to be the least threatened by the prospect of
advanced aliens, owing to their pluralistic concept of
God and their
traditionally much grander vision of the cosmos.
Among the world’s minority religions, some would positively welcome
the discovery of intelligent aliens. The Raëlians, a Canada-based
cult recently propelled to fame by its claim to have cloned a human
being, believe that the cult’s leader, Raël, a French former
journalist originally named Claude Vorilhon, received revelations
from aliens who briefly transported him inside a flying saucer in
1973. Other fringe religious organizations with an extraterrestrial
message include the ill-fated Heaven’s Gate cult and many UFO
groups. Their adherents share a belief that aliens are located
further up not only the evolutionary ladder but also the spiritual
ladder, and can therefore help us draw closer to God and salvation.
It is easy to dismiss such beliefs as insignificant to serious
theological debate, but if evidence for alien beings were suddenly
to appear, these cults might achieve overnight prominence while
established religions floundered in doctrinal bewilderment.
Ironically, SETI is often accused of being a quasi-religious quest.
But Jill Tarter, the director of the SETI Institute’s Center for
SETI Research, in Mountain View, California, has no truck with
religion and is contemptuous of the theological gymnastics with
which religious scholars accommodate the possibility of
"God is our own invention," she has written. "If
we’re going to survive or turn into a long-lived technological
civilization, organized religion needs to be outgrown. If we get a
message [from an alien civilization] and it’s secular in nature, I
think that says that they have no organized religion—that they’ve
Tarter’s dismissal is rather naive, however. Though
many religious movements have come and gone throughout history, some
sort of spirituality seems to be part of human nature. Even
atheistic scientists profess to experience what Albert Einstein
called a "cosmic religious feeling" when contemplating the awesome
majesty of the universe.
Would advanced alien beings share this spiritual dimension, even
though they might long ago have "outgrown" established religion?
Steven Dick, a science historian at the U.S. Naval Observatory,
believes they would. Dick is an expert on the history of speculation
about extraterrestrial life, and he suggests that mankind’s
spirituality would be greatly expanded and enriched by contact with
an alien civilization. However, he envisages that our present
concept of God would probably require a wholesale transformation.
Dick has outlined what he calls a new "cosmotheology," in which
human spirituality is placed in a full cosmological and astrobiological context.
"As we learn more about our place in the
universe," he has written, "and as we physically move away from our
home planet, our cosmic consciousness will only increase."
proposes abandoning the transcendent God of monotheistic religion in
favor of what he calls a "natural God"—a
superbeing located within
the universe and within nature.
"With due respect for present
religious traditions whose history stretches back nearly four
millennia," he suggests, "the natural God of cosmic evolution and
the biological universe, not the supernatural God of the ancient
Near East, may be the God of the next millennium."
Some form of natural God was also proposed by
Fred Hoyle, in a
provocative book titled The Intelligent Universe. Hoyle drew on his
work in astronomy and quantum physics to sketch the notion of a "superintellect"—a
being who had, as Hoyle liked to say, "monkeyed with physics,"
adjusting the properties of the various fundamental particles and
forces of nature so that carbon-based organisms could thrive and
spread across the galaxy. Hoyle even suggested that this cosmic
engineer might communicate with us by manipulating quantum processes
in the brain. Most scientists shrug off Hoyle’s speculations, but
his ideas do show how far beyond traditional religious doctrine some
people feel they need to go when they contemplate the possibility of
advanced life forms beyond Earth.
Though in some ways the prospect of discovering extraterrestrial
life undermines established religions, it is not all bad news for
them. Astrobiology has also led to a surprising resurgence of the
so-called "design argument" for the existence of God. The original
design argument, as articulated by William Paley in the eighteenth
century, was that living organisms’ intricate adaptation to their
environments pointed to the providential hand of a benign Creator.
Darwin demolished the argument by showing how evolution driven by
random mutation and natural selection could mimic design. Now a
revamped design argument has emerged that fully embraces the
Darwinian account of evolution and focuses instead on the origin of
life. (I must stress that I am not referring here to what has
recently become known as the Intelligent Design movement, which
relies on an element of the miraculous.)
If life is found to be
widespread in the universe, the new design argument goes, then it
must emerge rather easily from nonliving chemical mixtures, and thus
the laws of nature must be cunningly contrived to unleash this
remarkable and very special state of matter, which itself is a
conduit to an even more remarkable and special state: mind. This
sort of exquisite bio-friendliness would represent an extraordinary
and unexpected bonus among nature’s inventory of principles—one that
could be interpreted by those of a religious persuasion as evidence
of God’s ingenuity and foresight. In this version of cosmic design,
God acts not by direct intervention but by creating appropriate
natural laws that guarantee the emergence of life and mind in cosmic
abundance. The universe, in other words, is one in which there are
no miracles except the miracle of nature itself.
The E.T. debate has only just begun, but a useful starting point is
simply to acknowledge that the discovery of extraterrestrial life
would not have to be theologically devastating. The revamped design
argument offers a vision of nature distinctly inspiring to the
spiritually inclined—certainly more so than that of a cosmos sterile
everywhere but on a single planet. History is instructive in this
regard. Four hundred years ago Giordano Bruno was burned at the
the Church in Rome for, among other things, espousing the
notion of a plurality of inhabited worlds. To those whose
theological outlook depended on a conception of Earth and its life
forms as a singular miracle, the very notion of extraterrestrial
life proved deeply threatening. But today the possibility of
extraterrestrial life is anything but spiritually threatening. The
more one accepts the formation of life as a natural process (that
is, the more deeply embedded one believes it is in the overall
cosmic scheme), the more ingenious and contrived (dare one say
"designed"?) the universe appears to be.