I. The Question of Extraterrestrial life: An Interdisciplinary
Approach. 1. A Brief Glance at History. 2.
Interdisciplinary Aspects of the Debate. - II. The Research on
Extraterrestrial Life in the Scientific Context. 1. Life in the
Framework of Cosmic Evolution. 2. Scientific Projects on the
Research of Life. 3. The Search for Extraterrestrial Intelligence
(SETI). - III. The Religious and Theological Debate. 1. Historical
Aspects of the Relationship with Christian Thought. 2. Some
Theological Positions. - IV. Christian Theology and Extraterrestrial
Intelligence: Some Possible Approaches. 1. The Absence of Prejudicial
Arguments against the “Pluralistic” Hypothesis and the Reasonableness of the
“Classical” Position. 2. The Universality of the Image of the One
and Triune God in a Cosmic Context. 3. The Cosmic, and therefore
Creaturely, Headship of Christ.
1. The Question of Extraterrestrial Life: An Interdisciplinary
Approach
The observation of the starry sky has always provoked many
questions. Perhaps one of the most common concerns the possibility of the
existence of life on other planets similar to our own. From a historical
perspective, however, the question about life in the cosmos appears to arise
within a context different from that of the great questions regarding its
origin and all that characterizes the “cosmological problem.” If it is true
that the ancient theogonies predisposed human beings to imagine the presence of
anthropomorphic divinities in regions other than the Earth, the issue of a
plurality of worlds and whether they are habitable acquires force only when new
speculative visions and discoveries radically change mankind’s understanding of
his place in the universe. Generally speaking, this theme was not central to
philosophical thought, but its development in the natural sciences and, more
recently, in space technology has influenced various cultural sectors
(literature, customs, and cinema) besides having a significant impact on
religious and theological spheres. The hypothesis that life exists on worlds
other than our own is found in human culture from
the Ancient Age until our day. There is no doubt that to find forms of life on
other planets and, above all, to communicate with extraterrestrial intelligence
would represent one of the most extraordinary experiences in all of human
history.
1. A Brief Glance at History. The historical debate about a possible
plurality of inhabited worlds has been widely documented (cf. Crowe, 1988;
Dick, 1982 and 1996; review articles by Crowe, 1997, and Dick, 1993). In the
Ancient Age the atomists were probably the first to hypothesize the existence
of extraterrestrial life. Their mechanistic philosophy assigned to the infinite
number of atoms in the cosmos the capacity to give rise to an infinite number
of bodies in a multitude of possible combinations, hence also beyond the Earth.
Epicurus (341-270 B.C.), and then more importantly Lucretius (99-55 B.C.),
affirmed a kind of “Principle of Plenitude,” according to which all the
potentialities of matter were
destined to be realized sooner or later, in this way giving rise to a world the
perfection of which would be proportional to the richness of the existence it
contained. The question regarding possible inhabitants of the moon —a question
intuitive and spontaneous given the proximity and the large apparent size of
our satellite —appears in the works of various classical authors, including
Plutarch (45-125). Within his De facie quae in orbe lunae apparet,
a small treatise of philosophical cosmology on the difference between the properties
of the Earth and the moon, the Greek writer presents a debate about the origin
of the shadowy spots apparent on the lunar surface. Philosophical thought
descending from Aristotle (384-322 B.C.) will find greater difficulty in
speculating about the presence of inhabitants of other worlds as the heavenly
sphere progressively becomes marked by the characteristics of eternity,
immutability, and incorruptibility. That sphere is radically distinct from our
terrestrial environment (the so called “sub-lunar” world), to which belongs
instead change and contingency. The lunar sphere, in which some mutations were
also observed, will thus remain halfway between the two.
In the Middle Ages, Christianity was not opposed to the idea that
God could have created other worlds, even ones more perfect than our own, but
the theme did not directly concern the possibility of their being inhabited. In
the cosmology of De docta ignorantia, Nicholas of Cusa
(1401-1464) alludes to possible inhabitants of other worlds (which he naïvely
placed on the stars). He also tried to systematize from a philosophical point
of view the relations such worlds would have with the Earth and its
perfections, as well as that between the nature of their inhabitants and our
intellectual nature. In a reflection shared by many of our contemporaries, the
Cardinal-philosopher concluded that we simply cannot know anything about such
comparisons: “The inhabitants of other stars, wherever they are, do not have
any proportion with the inhabitants of our world, also if their whole region is
in a concealed proportion with our own, for the finality of the universe [...].
But, since this region remains unknown to us, also its inhabitants remain
completely unknown to us.” (Book. II, ch. 12). Giordano Bruno (1548-1600), the
renaissance interpreter of the “Principle of Plenitude,” hypothesized the
presence of life diffused throughout the whole universe, not only in the form
of inhabited stars and planets, but also as a vital principle able to provide a
soul to the stars, planets, comets, and indeed to the whole universe. Galileo
(1564-1642) and Kepler (1571-1630) never addressed the theme directly, but
understood that the heliocentric system placed the Earth in a condition of
greater similarity with other solar planets. As had Plutarch and not without
irony, both of them asked themselves whether the visible and regular spots on
the surface of the moon could have been the work of intelligent inhabitants
(cf. C. Sinigaglia, Lo “scherzo” di Plutarco e il “sogno” di Keplero,
in Colombo et al., 1999, pp. 155-168).
By the middle of the 17th century, thanks to the use of the
optical telescope as a scientific instrument for astronomical observation, an
immense number of stars invisible to the naked eye were now revealed, and thus
interest in the theme of life in the universe experienced a rebirth. The rapid
diffusion of works in favor of a plurality of inhabited worlds stands as proof.
For example, the work of Bernard le Bovier de Fontenelle (1657-1757), Entretiens
sur la pluralité des mondes (1686), appeared in dozens of editions and
translations, and the posthumous work of Christian Huygens (1629-1695), Kosmotheoros,
sive de terris coelestibus earumque ornatu conjecturae(1698), was quickly
translated into five languages.
The progressive widening of horizons caused by the scientific
observation of the cosmos stimulated astronomers to publish works concerning
the possibility of forms of life beyond the confines of the Earth. Initially
William Herschel (1738-1822), well-known for his studies on the spatial
distribution of stars aimed at drawing the overall structure of our Milky Way,
then Richard Proctor (Other Worlds Than Ours: The Plurality of Worlds
Studied under the Light of Recent Scientific Researches, 1871), and above
all Camille Flammarion (La pluralité des mondes habités, 1862),
contributed to the debate within the scientific world throughout the 19th
Century. The work of the French astronomer experienced an extraordinary
diffusion, with over 30 editions in fewer than twenty years and in print
without interruption until 1921. It was again an astronomer, the Italian
Giovanni Schiaparelli (1835-1910), who provoked interest in the possibility of
intelligent life on the planet Mars with his famous observations of “channels”
on the red planet’s surface, regular structures to which attention had earlier
been drawn by Angelo Secchi (1818-1878), a Jesuit astronomer. The writings of
Schiaparelli on the planet Mars, (re-edited in Italian with the title La
vita sul pianeta Marte: tre scritti su Marte e i marziani, Milano, 1998),
together with those of Proctor and Flammarion, brought about a cultural
phenomenon that ended up generically identifying inhabitants of other worlds
with the term “Martian.” The position of a non-astronomer, Alfred R. Wallace
(1823-1913), a naturalist and an original supporter with Darwin of the theory
of evolution by natural
selection, must also be recalled as part of the debate between the 19th and
20th centuries. In his work, Man’s Place in the Universe: A Study of
the Results of Scientific Research in Relation to the Unity or Plurality of
Worlds(1903). Wallace prepared a vigorous defense of an anthropocentric
universe, in open disagreement with the pluralist position. This essay, which
enjoyed wide diffusion due to the scientific environment where it originated,
provided a number of arguments in defense of the uniqueness of human life
within the cosmos.
From the middle of the 20th century, the progress of
radio-astronomy and the initiation of space research, together with physical
images of a universe of unsuspected dimensions of space and time, offered a
vision of man’s place in the cosmos that logically raised the question of the
possibility of extraterrestrial intelligence. Works by scientists such as H.
Shapley, Of Stars and Men (Boston, 1958), and of Shklovskii
and Sagan, Intelligent Life in the Universe (San Francisco,
1966), exercised great influence, for example, the texts of General interest in
the theme, however, has been sustained above all through other phenomena, such
as science-fiction literature and the cinema.
In the more narrowly scientific realm, the 19th century’s
enthusiasm for a possible “close encounter” with other inhabitants of the solar
system has been replaced by the methodical research for elementary life forms
or pre-biotic material in environments similar to our solar system, not to
mention the initiation of long-term programs in radio-astronomic exploration of
more remote environments (see below, II, nn. 2 and 3). At the same time, the
opportunity was not lost to send “messages in a bottle,” such as the plate with
an image of a human couple and some coded scientific data placed on the
automatic probes Pioneer 10 and 11 (launched in 1971), the
first to venture outside the solar system; digitalized images and sounds of
planet Earth on the similar Voyagerprobes (1977); and a radio
transmission in binary code sent towards the galactic globular cluster M13 by the
Arecibo radiotelescope (1974).
2. Interdisciplinary Aspects of the Debate. The theme of
cosmic life is brought to today’s culture by science, not philosophy. It
reaches the public mostly through the mass media, literature of different
genres, and certain other artistic expressions. It suffices to think of the
science-fiction novels of H.G. Wells, author of War of the Worlds (1898),
which continue to inspire, even after a century, films like Star Wars (from
1977 onward) by George Lucas. Consider also the diffusion of novels by Isaac
Asimov, some of which have also been reproduced on the screen. Other forms of
inspiration also exist, like the novels of C.S. Lewis in his Ransom’s Space
Trilogy (1938-1945), also known as Perelandra,
where the visit to worlds other than our own involves the themes of virtue and
sin, of liberty and redemption, of the diversity of creatures and their
dependency on a common Creator. The great question regarding the significance
of human life in the universe and its relationship with transcendence is one of
the central themes of 2001: A Space Odyssey (1968), written by
Arthur C. Clarke and directed by Stanley Kubrick.
The peculiarity of the subject of life beyond the Earth’s confines
entails an inevitable meeting point in which the great themes of anthropology,
philosophy and religion are expressed sometimes unconsciously, sometimes more
explicitly. The implications of possible contact with other intelligent forms
of life can easily be grasped. It is certainly expected that after communicating
with other intelligent forms of life one would desire to check our knowledge of
the laws that govern the physical universe (some of which could be unknown to
us), get some information regarding the cosmic context of the human species,
gain insight on the origin and diffusion of life, including the possibility of
its survival in a technological era. However, “the man on the street” (and
likely all of us) would certainly ask civilizations different from our own
about the meaning of conscious free life and the knowledge they have of a
possible Creator. Humans would ask the others about the
existence of God.
The humanistic and religious significance of the theme is easily
noticed when observing that in many works of literature, art, and cinema, the
“cosmic space” context (or the “heavenly” context, if you prefer) provides
implicit references to the great everlasting questions, such as the mythical
fight between light and dark, the choice between good and evil, human inquiry
about life after death and the way to reach or merit it. Extraterrestrial life
contexts re-propose the intervention of mediators from faraway worlds, the
delivery of moral messages that awaken in human beings the existential
questions that ordinary terrestrial life has made dormant. Moreover, it is
frequent that the contact with civilizations different from our own is there
represented as a powerful conceptual place in which the human family returns to
wisdom and self-understanding. On the other hand, as shown by some movies, it
also happens that humankind rediscovers its unity of origin and its common aims
when prompted by the search for defenses against possible cosmic perils or when
urged by the necessity to achieve some efficacious and coordinated behavior on
a planetary scale.
As Paul Davies has intelligently pointed out, an implicit
religious dimension is concealed within research for extraterrestrial
life. This dimension expresses itself in a precise literary fashion and
aims to explore human spirituality in relationship to meeting “the other.” To
quote from the conclusions of his book, Are We Alone?: “The
powerful theme of alien beings acting as a conduit to the Ultimate—whether it
appears in fiction or as a seriously intended cosmological theory—touches a
deep chord in the human psyche. The attraction seems to be that by contacting
superior beings in the sky, humans will be given access to privileged
knowledge, and that the resulting broadening of our horizons will in some sense
bring us a step closer to God. The search for alien beings can thus be seen as
part of a long-standing religious quest as well as a scientific project. This
should not surprise us. Science began as an outgrowth of theology, and all
scientists, whether atheists or theists, and whether or not they believe in the
existence of alien beings, accept an essentially theological world view”
(Davies, 1995, pp. 137-138).
The religious resonance just highlighted, of course, is not
foreign to systematic theology. Christian theology would particularly be
involved in light of its “register of uniqueness.” This “register” seems to
regulate the relationship between God and man, with its apex reached in the
mystery of the Incarnation of
the Son of God . For theology, to widen the horizon and
consider intelligent beings other than humankind could represent the last
possible consequence of a kind of “extended Copernican Principle,” that first
deprived human beings of the geometric center of the known universe, then of
the uniqueness of their biological history on the Earth, and finally of the
centrality of their consciousness within the cosmic panorama. Although theology
has not dedicated special reflection to this point, it possesses the resources
to confront this issue thematically. The general idea shared by the public and
the mass media, however, is that a “close encounter of the third kind” would
drastically call into question some important principles of theological establishment.
As outlined in another article of this Encyclopedia when speaking of the
relevance of the natural
sciences for the work of theologians, if theology is not obliged to
give an account for all that is merely possible, its discourse on God and human
beings —once developed within a contemporary scientific context— nonetheless
cannot ignore at least some of the questions that the presence of
extraterrestrial life would provoke.
II. The Research on Extraterrestrial Life in the Scientific
Context
The analysis of our theme within a scientific context must begin
with an important clarification. The debate concerning the actuality of
unidentified flying objects (UFO) and their possible extraterrestrial origin
does not pertain to the object to which science intends to refer when speaking
of extraterrestrial life (ETL) and extraterrestrial intelligence (ETI). That
debate is outside the boundaries of the scientific and interdisciplinary
perspective here assumed. Moreover, the impossibility of having public,
scientifically-ascertained knowledge, of the data claimed by UFO’s supporters
prevents our being able to consider the subject with adequate rigor.
1. Life in the Framework of Cosmic Evolution. We do not know if
life is a unique event within cosmic history, one which happened only on this
remote planet of one of 1011 stars of our Milky Way, only
one of the 1011 or 1012 galaxies that
likely populate our universe; or, on the contrary, if it is a rather widespread
phenomenon. We certainly know that its appearance requires an incredible series
of delicate steps and conditions within space and time, the consideration of
which cannot be avoided when we desire to evaluate the possible diffusion of
life on a cosmic scale.
Neither are we able to comprehend whether the whole of these
delicate conditions must be considered as a highly improbable event or as a
sort of cosmic imperative, linked to the action of a process or of a law that
inevitably guides the various steps of the history of the universe (cf. de
Duve, 1995). In other words, we do not know if life is a universal and
quasi-inevitable phenomenon, reproducing itself everywhere that the conditions
permit it to do so, as has been suggested by Christian de Duve or Manfred
Eigen; or if life is equivalent to a mere probabilistic number, the result of
chance at the roulette wheel of cosmic evolution and a phenomenon that does not
have any significance, as laconically sanctioned by Jacques Monod and Steven
Weinberg. But the philosophical perspective intuits that the richness of life’s
complex phenomenology, the teleology of its processes, and its absolute
singularity in comparison to inorganic matter all tend to imbue the incidence
and the possible significance of life with categories must go beyond a
simplistic dichotomy between chance and necessity.
Abstracting from the physiochemical conditions related to the
formation of environments adequate for life, which in turn depend on the
numerical values of the constants of nature that regulate and determine the
intrinsic structure of the universe —conditions that are usually discussed as
related to the Anthropic
principle — I will briefly summarize here some of the main
steps that must precede any possible appearance of life in the cosmos.
First of all, the elements necessary for life (e.g., oxygen,
carbon, potassium) are present only after at least one or maybe two generations
of massive giant stars. At the end of the thermodynamic and thermonuclear
evolution of such stars, the products of their explosions as supernovae make
available an adequate abundance of these elements in cosmic space. Within this
environment enriched by heavy chemical elements —the universe begins its evolution
composed almost essentially of the lightest element, hydrogen, with a small
fraction of helium— other types of stars (main sequence dwarfs) such as our sun
must then form, which are more stable and have a longer evolution. Only these
stars have an average life long enough (at least several billion years) to give
orbiting planets a dependable source of energy for a time sufficient to permit
the slow development from very simple to more complex forms of life.
Candidate planets to host a biosphere must then be of a mass
sufficiently large to retain a gaseous atmosphere gravitationally, but also
sufficiently small to grow cool in a reasonably short time. Planets with a mass
such as those of Jupiter or Saturn, for example, have not yet concluded their
cooling and therefore have not yet formed a solid surface, even though their
birth was contemporary with the Earth’s (around 4.6 billion years ago). In
addition, the planet’s distance from the central star must be optimal, so that
the planet receives from its star a necessary but not excessive quantity of
heat. Hence the star cannot belong to a binary or multi-stellar system (the
incidence of which is statistically quite high), because these systems cannot
guarantee sufficient stability for the planetary orbit.
Moreover, evolution of
life on a planet fit to host it also has its own growth times. Not to mention
the time necessary for the formation of life's indispensable chemical
compounds, such as water, numerous compounds of carbon and oxygen, and, as far
as possible, those necessary to form a liveable atmosphere, it is also
necessary to wait for the patient diffusion of the more simple life forms. With
the products of their biochemical processes, simple life forms supply the
biosphere with necessary substances for superior life forms, which are
organically more complex. We know that the time elapsed on Earth from the
formation of the first micro-organisms to the appearance of mammals was not
less than three billion years. If we consider that the time separating the
universe today from its earliest phases of very high density and temperature is
certainly not less than 13 billion years, we must conclude that a cosmic time
significantly less than this would very probably have been insufficient in any
place of the cosmos to allow for the development of forms of life similar to
those known today on Earth.
In 1961, Francis Drake attempted to formalize at least some of the
preceding conditions in order to estimate what chance there might be to enter
into communication (plausibly by radio) with other forms of intelligent life,
at least within our galaxy. The use of what will later be called “Drake’s
equation” concerns the computation of a series of restrictive probabilities,
which are multiplied with each other in order to estimate the number, N, of
civilizations in the Milky Way Galaxy possibly able to communicate with us. In
the formula proposed by Drake, N = R* fp
ne fl fi fc L, the value R* indicates
the rate of formation of the central stars with adequate energetic
properties; fp the fraction of them that could have associated
planets; ne the number of them with conditions similar to
those of the Earth; and fl, fi, and fc the
fractions that could develop, respectively, life, intelligent life, and
intelligent life at a level of technological civilization. The last
factor, L, regulates the “average life” of a technological
civilization on a planet. The estimates for N are, as one might expect, very
diverse. To Drake’s original calculation that resulted in an approximate value
for N = 100,000, other scientists oppose a value around N=100,
but still other experts have very different opinions, according to some of whom
there would be only one active and technologically developed civilization for
every 300 galaxies, i.e., ours would be the only such civilization in the Milky
Way and in the nearest 299 galaxies surrounding it (the more critical
estimations are by Rood and Trefil, 1981).
As some authors have opportunely pointed out (cf. McMullin, 1980,
pp. 83-84), the principal limit of this type of equation is the lack of a
realistic model that satisfactorily describes the processes whose fractions of
probability of occurrence are to be calculated. For example, to know the
fraction of stars that could have planets similar to the Earth, we must have a
precise model for planet formation from star clouds. This model should also
have parameters describing the various characteristics of the formed planets,
in order to select how many planets would be suitable. Unfortunately, however,
we do not possess until today such a model. Things get even more complicated
when we consider that we know very little of the “why” of the origins of life
on a planet and even less with respect to intelligent life. Therefore we do not
have a realistic model to evaluate whether or not this must happen a certain
number of times or never at all. The logic of a statistical theory (for
example, the kinetic theory of gas) is to deduce an average behavior for a
larger scale on the basis of one’s knowledge of known smaller-scale processes
(for example, the principles that regulate the motion of a particle). A
statistical theory for the formation of planets with a biosphere, but above all
a statistical theory for the formation of life, is not rigorously possible
because we do not know the modality of these processes, that is, a complete and
reliable theory to interpret them with a sufficient level of accuracy.
Moreover, in nature we have a unique known event, namely us
terrestrials, and we cannot securely distinguish what is necessary for our
appearance from what might not be necessary. In short, we have insufficient
information.
Inevitably, the scientific disciplines that tackle the theme of
life in the universe try to use deduction as far as seems reasonable,
attempting to link our inferences with what knowledge we have of the cosmos and
its environments. At the same time, I believe that in a theme such as ours the
attitude better methodically grounded will always be induction, together with
the patience to wait and discover.
2. Scientific Projects
on the Research of Life. Contemporary science confronts the theme of life in the cosmos
in various thematic contexts. They include the research and the study of
organic compounds and of biological structures possibly present in interstellar
space or on the surface of heavenly bodies (comets, asteroids, satellites or
planets) adequately hospitable to them; the research for at least some
elementary form of life in particular places within our solar system; the
detection and the study of planetary systems formed around other stars in a
manner similar to our solar system; the theoretical and experimental
reconstruction of the processes that might have given origin to life on Earth
in order to better understand such mechanisms on a cosmic scale; and finally,
the research for possible radio signals of intelligent origin by means of
radio-telescopes partially or totally dedicated to the sounding-out of the sky
in centimetric and decimetric wavelengths. All this activity has entered the
panorama of scientific research as a new discipline called exobiology, astrobiology,
or also bioastronomy. The status of knowledge in this area and the
main research programs devoted to seek extraterrestrial life, are easily found
in many published books and reviews, including Proceedings of International
Conferences (cf. for instance Papagiannis, 1985; Shostak, 1995; Batalli
Cosmovici et al., 1997; Grady, 2001; Goldsmith and Owen, 2002; Dick and Strick,
2004; Meech et al., 2007). Since 1982, the international scientific community
has granted such research activity official status within its international bodies
establishing the “Commission n. 51” of the International Astronomical
Union. A good number of websites run by scientific Institutions, among
which there is the official
NASA website for astrobiology also supply an ever wider public
with updated information.
From a historical perspective, the first official entry within a
strictly scientific environment of the theme of extraterrestrial life dates
back to the second half of the 19th century, namely, the observation of the
channels on Mars by Schiaparelli. Beginning in August, 1877, their possible
intelligent origin was the object of dispute throughout the world for about
thirty years. The mysterious images were then recognized to be natural
structures thanks to the use of observational instruments with a high power of
resolution. The “red” planet, on which Herschel had indicated two polar caps
thought to be formed from frozen water (but which today we know to be formed
from solid state anhydrous carbon), remained almost until today a potential
candidate for the presence of some elementary life forms. Mars became the
object for space missions immediately upon the birth of astronautics, first with the passing
flight of a number of probes (Mariner, 1964-1971), then with soft
landings on its surface (Viking in 1976), and finally with
reconnaissance missions starting with self-propelled automatic probes (Pathfinder in
1997). Both the Viking probe and the Pathfinder mission
conducted experiments to verify the existence of possible forms of life,
reporting negative results. During the first decade of the third millennium
more perfected space missions have been projected and carried out. Projects for
Mars exploration include the European Mars Express, launched in
2003, and NASA’s rovers Spirit and Opportunity, successfully landed on January
2004, the orbiting probes Mars Odyssey and Mars
Reconnaissance Orbiter, and the complex Phoenixmission, which
landed on May 2008.
Water was almost certainly present on Mars in the past, and water
ice evidences have been announced in Summer 2008 by Phoenix lander,
but the results acquired within the first decade of the 21st century tend to
exclude the possibility of life forms on planets within our solar system due to
the prohibitive chemical and physical conditions present within their
atmospheric envelopes or on their surfaces. By the end of 20th century,
scholarly interest has shifted to some of the massive satellites of solar
system’s bigger planets. Images obtained in the 1970s and 1980s from the Pioneer and Voyager probes,
and later from the missions Galileo (launched in 1989,
released a probe to Jupiter in 1995) and Cassini-Huygens (launched
on 1997, began orbiting Saturn in 2004), have attracted researchers’ attention
to some of the satellites of Jupiter and Saturn. Particular attention has been
paid to the Jupiter satellite Europa due to the discovery of the presence of
water there, and to Enceladus and Titan in orbit around Saturn, which also
exhibit very interesting morphological characteristics.
Thanks to the development of Earth’s observational technology and
above all to the use of orbital instruments such as the space telescope Hubble,
many star systems have been identified in the last few years which show a star
encircled by one or more planets. So far, the planets discovered have masses
comparable or greater than that of Jupiter, the majority of these being too
close to the central star and therefore ill-suited for life.
An updated information on extra-solar planetary systems is
available on the website Planet Quest, edited by the
Jet Propulsion Lab and the NASA. It must be taken into account that
present observations tend to pick out only the more massive planets, due to
instrumental constraints. Thanks to a new generation of technology, such as
that of the Next Generation Space Telescope, which will be
operative in orbit during the second decade of the 21st century, we will
probably be able to identify planets with a small or intermediate mass, and
make more accurate measurements to acquire information on the possibility that
such bodies host a chemistry suitable for life. From a theoretical point of
view, it appears the formation of planets orbiting around a star is a
relatively frequent phenomenon, although the physical characteristics that
would make them hospitable for life are rather restrictive, as we have already
seen.
Objects of interest for contemporary bioastronomy are not only
planets and satellites, but also very small bodies, such as asteroids and
comets, and, in general, the vast regions of interstellar space. With radio
frequency observations and infrared spectroscopy, it has become possible to discover
the presence of over one hundred different types of molecules in interstellar
space, including water, carbon monoxide and dioxide, ammonia, methanol,
formaldehyde, and various carbon, silicon and nitrogen compounds, as well as a
certain number of amino acids. Many of these molecules, some of which have been
found directly on meteoric residues or observed on comets, are identical to
those that characterize the chemistry for living organisms and therefore raise
questions about their possible role in pre-biotic processes and about their
possible origins from biological processes already in existence. Presently,
however, no nucleic acids or other biochemical structures of a cellular origin
have been observed —not even within the vast environment of interstellar space—
that lead us to think micro-organisms are present beyond Earth.
Notwithstanding the absence of results that might have
demonstrated traces of life, past or present, in environments other than those
of our own planet, we must recognize that scientific activity confronts us with
a new way of considering life, a way that for the first time fixes coordinates
on the cosmic dimensions and no longer solely on the terrestrial.
3. The Search for
Extraterrestrial Intelligence. Within the context of the relationship between scientific
activity and the research of extraterrestrial life, the SETI program (Search
for Extraterrestrial Intelligence) deserves special mention. The
idea of dedicating radio-telescopes to listen for possible intelligible signals
coming from places beyond our solar system derives from the suggestion of
Cocconi and Morrison (1959). At the dawn of radio-astronomy, this suggestion
demonstrated the theoretical possibility of terrestrial instruments receiving
from space, even at enormous distances, electromagnetic flux densities
comparable to those that we emit here on Earth when transmitting ordinary radio
programs. The authors’ advice was to begin listening to frequencies adjacent to
the neutral hydrogen emission line at 21 cm (1420 MHz), which could easily be
chosen as a reference point for other technological civilizations, given its
intensity and diffusion throughout the cosmos. In 1967, an echo of a possible
radio contact with extraterrestrial civilizations sounded in public opinion when
Burnell and Hewish discovered the first pulsar. Until Goldreich and
Julian definitively demonstrated in 1969 that such regular and intermittent
signals were produced by neutron stars in rapid rotation, some believed it was
possible these signals were of an intelligent origin, jokingly calling
them little green men.
Beginning in 1961, a progressive involvement on the part of
researchers and the employment of new instruments gradually brought about the
formation of the SETI Institute,
which provides a good amount of online documentation. Today the Institute has
its own projects and researchers, but works in collaboration with NASA, as also
with other major radio-astronomy research institutes on the planet. In the
context of an interdisciplinary discussion, the Seti Academy Committee is
also worth mentioning. In collaboration with other scientific institutions,
this committee of the International Academy of Astronautics (IAA) dedicates
part of its activity to the study of the social and cultural consequences of a
possible contact with other civilizations and to preparation of possible
protocols for communication. Some international procedures have already been
established; in case an event of this type were to be verified, they foresee independent
confirmations of the discovery, international bodies to be informed, and
priorities to follow.
Beyond any optimistic interpretation of Drake's equation, there is
an important factor that provides motivation to sustain SETI research. As time
goes on, the volume of space in which the terrestrial radio signals are
journeying increases proportionally to the cube of the distance covered by the
speed of light (the velocity of radio signals) during that same time. Thus, the
probability for receiving a possible extraterrestrial response likewise
increases as time progresses. At this time, terrestrially produced radio waves
have reached the stars (and possible planetary systems associated with them)
inside a sphere with a radius of approximately 70-80 light years, allowing us
for the moment to conclude that extraterrestrial civilizations do not exist
within a distance of around 30-40 light years from the sun (computing the time
a possible radio answer needs to travel back), or, if they do exist, they are not
capable of responding or perhaps do not have the intention to reply to our
signals. In this context, one may refer also to the fact that the great
radio-telescope of Arecibo (Puerto Rico) was deliberately used in 1974 to send
toward the globular cluster M13 a radio message of 1679 bits in binary code,
decodable in a black and white image containing information on Earth and human
biology. The research projects for the 21th century involve interferometric
radio-telescopes in orbit around the Earth or on the concealed face of the moon
(i.e., in the shadow of signals coming from the Earth) in order to increase the
power of resolution and the sensitivity for reception of possible intelligent
extraterrestrial signals.
For the more optimistic, such as the radio astronomer Ron
Bracewell, the many technological civilizations that might populate the
universe would already have a communicative network in place, a kind of Galactic
Club (Bracewell, 1979), which humans must enter sooner or later. But
the hypothesis that advanced civilizations may have very diffuse presence has
often been contested, because there has not yet been contact with any of them,
neither in the present nor in the historical past. If there were a million such
civilizations in our galaxy, they would be separated by a distance of
approximately 100 light years from each other. Historically known as the “Fermi
Paradox” for the Italian physicist who, almost as a joke, made this type of
calculation for the first time in 1950 during a lunch at Los Alamos, this
problem is often posed in a colloquial fashion with the question where
are they? The proposed responses have varied, ranging from the
suggestion that such contacts may have already happened in ages when humans
were not in a position to appreciate them, to the fact that there would be a
certain resistance to the establishment of such relationships given the
enormous technological or even cultural differences, differences that could
also account for a sort of “invisibility” of their presence in our midst. The
variables of the problem, many of which certainly come from outside the
scientific sphere, are such that the Fermi Paradox serves as a useful
admonition, albeit it is not an apodictic argument. Considerations similar to
Fermi’s and equipped with opportune solutions were made around 1930 by
Kostantin Tsiolkovsky (1857-1935) within a philosophical climate known as
“Russian Pancosmism” (cf. Lytkin et al., 1995).
III. The Religious and Theological Debate
The probable presence of life, particularly of other intelligent
creatures, in environments different from the Earth has never constituted a
specific topic of theological speculation. Concerning the Magisterium of Roman Catholic Church,
it has no official teachings regarding ET life. Holy Scripture, even when it
presents the relationships between God and humans in a cosmic context, does not
mention it. Some writers love to cite as a possible exception a verse from the
Gospel of John: “I have other sheep that do not belong to this fold. These also
I must lead, and they will hear my voice, and there will be one flock, one
shepherd” (Jn 10:16); however, though certainly suggestive, it does
not in reality offer any serious ground for exegesis in such a sense.
Throughout history, theological reflections that could offer possible
references to the ET debate are very few and fragmented. However, a number of
reviews about different theological positions are now available. Throughout
history, theological reflections that could offer possible references to the ET
debate are very few and fragmented. However, a number of reviews about
different theological positions are now available (cf. Dick, 1996; Crowe, 1997;
Corbally, 1997; Dick, 2000; Russell, 2001; George, 2002).
1. Historical aspects of
the relationship with Christian thought. Of the earliest texts concerning our issue
is a letter by Pope Zachary (741-752), in which he mentions that the priest
Virgil taught a doctrine on the plurality of inhabited worlds. Zachary
disapproved the idea that there were inhabitants at the poles, on the moon, or
on the sun (quod alius mundus et alii homines sub terra sint, seu sol et
luna: cf. Epistula XI ad Bonifacium, PL: 89, 946-947). The
doctrinal motive for such reprimand was to prevent the introduction of elements
of novelty that, by calling into question the unity of the human family, would
have made it more difficult to understand the relationship to God of men who
were not descendants of Adam, including their moral position with respect to
original sin. In 1277, with the intention of protecting the freedom and
omnipotence of the Creator, the bishop of Paris, E. Tempier, condemned a
proposition of the Aristotelian tradition according to which the First Cause
could not have created many worlds. However, this censure did not mention
anything about their possible inhabitants. Some years before, Thomas Aquinas
(1224-1274) had responded in his Summa Theologiae to the
question of whether other worlds existed, affirming that only one world existed
(cf. pars I, q. 47, a. 3). But we cannot make direct use of the medieval debate
on the multiplicity of worlds to know the position of Christian theology on
extraterrestrial life. The medieval concept of “many worlds” was not equivalent
to what we use today when referring to different planets that could be
inhabited. By the “oneness of the world,” medieval authors were referring
rather to the unity of the universe,
which derived from the unity of its Creator and from the unity of His final
causality for all that exists. In the question of the Summa cited
above, Aquinas in fact associated the idea of a plurality of worlds with the
supporters of chance who, like Democritus, denied an ordering wisdom. The
warning of Tempier, in which the concept of mundus (world) did
not totally coincide with the usage of Thomas Aquinas, was intended only as a
corrective of an academic nature rather than as an ecclesiastical intervention
in the strict sense. It was aimed at maintaining unaltered the characteristics
of the Creator, and this not so much within the sphere of the real but rather
within the sphere of the possible. The correct way to understand a plurality of
systems, all depending from an unique Cause, was also maintained later by
Thomas Campanella, remembering in his Apologia for Galileo(1622)
that the observations of the new worlds made by the telescope of the Italian
scientist did not contradict any religious tenet (cf. Apologia pro
Galilaeo, ch. III, ad nonum).
The debate about the heliocentric system raised in the 15th and
16th centuries had no official repercussions for our theme. Some ecclesiastics
expressed their private opinion that to lower the Earth to the level of other
planets could lead some innovative spirits to go still further, even to the
point of supposing the existence of inhabitants on those planets, with the
consequences foreseen by Pope Zachary in the 8th century. Just so, the idea was
manifested in a letter by the abbot Giovanni Ciampoli to Galileo sent on
February 28, 1615 (cf. Galileo, Opere, edited by A. Favaro,
Florence 1968, vol. XII, p. 146) and in a letter sent to Pierre Gassendi
(1592-1655) by the abbot Le Cazre (cf. P. Gassendi, Oeuvres, Lyon
1658, vol. VI, p. 451). The 17th century was characterized by a general
attitude of prudence, as also indicated by the fact that Fontenelle’s
essay, Entretiens sur la pluralité des monds, was placed on the
Index of Prohibited Books in 1687.
In the 18th century, the theological climate seemed to change. No
specific solutions were offered to frame or solve the dogmatic problems that
extraterrestrial life could pose for Christianity, but the entire theme was
regarded with greater openness and without any particular fear. In the first
place, theologians seemed to underline more the greatness of the Creator and
the incomprehensibility of his plans for the universe. Anglican apologetics
offered a connecting point by inserting the possibility of extraterrestrial
life into its natural theology, that in the pages of William Derham became
an Astro-theology (1714). Of greater significance, however,
was the reaction of many Christian authors against the work of Thomas Paine
(1737-1809), The Age of Reason (1793), a text that for the
first time directly proposed a radical incompatibility between the Christian
religion and the existence of intelligent extraterrestrial life. According to
Paine, the discovery of non-terrestrial life would inevitably lead to a
repudiation of religion: “Are we to suppose that every world in the boundless
creation had an Eve, an apple, a serpent and a redeemer? In this case, the
person who is irreverently called the Son of God, 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” (The Age of
Reason, in "Paine. Representative Selections", ed. by H. Hayden
Clark, New York 1961, p. 283). Paine's criticism was not endorsed by sincerely
believing astronomers who were also favorable to a pluralist hypothesis, as
were T. Wright, J. Lambert and the prestigious William Herschel, and moreover
it gave rise to theological works aimed at refuting that thesis, as T.
Chalmers’ Astronomical Discourses (1817), T. Dick’s The
Christian Philosopher (1823), and T. Dwight’s Theology
Explained and Defended in a Series of Sermons (1818).
In the 19th century the essay of the German theologian Joseph
Pohle, Stellar Worlds and their Inhabitants (Die
Sternenwelten und ihre Bewohner, Köln 1884), re-edited many times for
approximately twenty years, plainly favors the hypothesis of a plurality of
inhabited worlds. Given that the physical universe is so vast and that the
reason for creation is to give glory to God, Pohle deduces that such glory must
be bestowed by many intelligent beings dispersed throughout the cosmos and that
have a direct relationship with the material universe, unlike the multiplicity
of angels, whose nature is purely spiritual. An echo of this conclusion can be
found in one of the most widely diffused European theological textbooks of the
20th century (cf. M. Schmaus, Katolische Dogmatik, Munich 1957,
vol. II, n. 109). Pohle’s position will be shared by various scientists of his
era, among them the Italian priest-astronomers Angelo Secchi and Francesco
Denza.
2. Some Theological
Positions. Apart from a few exceptions, today’s theological literature
does not give specific attention to our theme. Theological textbooks present
only fleeting glimpses of it, usually following a line of prudent openness to a
possible occurrence that, in the end, must be a factual event and not a
theoretical deduction. In the second part of the 20th and in the beginning of
21st centuries, explicit references to the theological import of ETL can be
found, among others, in Grasso (1952), Perego (1958), Davis (1960), Zubek
(1961), McMullin (1980), Corbally (1997), Russell (2001), George (2002), Peters
(2003), Delio (2007), and in a number of contributions collected by Dick
(2000). The issue received attention also by E. Milne (Modern Cosmology and
the Christian Idea of God, Oxford 1952), E. Mascall (Christian Theology
and Natural Science, London 1956), and above all K. Delano (1977). Paul
Tillich complains of the absence of such reflection within the theological
field (cf. Systematic Theology, vol. II, Chicago 1957, pp. 95-96).
Teilhard de Chardin dedicates only a brief essay to our topic (La
multiplicité des mondes habités, 1953), to which he added an even shorter,
but interesting, footnote. Karl Rahner maintains an open position and does not
refuse to tackle the problem, but intuiting the major Christological import of
the subject preferred not to offer apodictic solutions (cf. Fisher and
Fergusson, 2006).
The point of departure for most theological reflections basically
remains Pohle’s thesis: the Creator’s greatness and glory are compatible with
the gift of life and of intelligent life in the cosmos, also in numerous
environments other than the Earth, although we do not know what God’s plans are
for these creatures. Thereupon, theology immediately offers a clarification
already present in all the works of the writers who replied critically to
Paine: redemption from original sin regards the human family and cannot be
transposed into the life of other creatures. The same consideration was made
centuries earlier by the Franciscan William Vorilong (1390-1463), but it
constitutes only a first approach to the problem (cf. McColley and Miller,
1937).
Some writers have gone still further. According to Mascall, it
would not be difficult to acknowledge the possibility of various hypostatic
unions of the Incarnate Word if this were judged opportune by the universal
God’s will of salvation, a position possibly shared also by Rahner. On the
contrary, Milne suggests that the uniqueness of the Incarnation could be
compatible with the fact that radio communication between civilizations would
become the vehicle of informing other intelligent creatures about the history
of salvation God realized on behalf of terrestrials and extending to other
creatures a sort of “redemptive information” capable of moving them to give
thanks to God or to believe in Him. The position of Kenneth Delano, who
approaches the question within a Catholic perspective, shows a notable flexibility.
After recalling the fittingness of associating the greatness of God with a
creation much richer than one could imagine, he indicates the necessity for
genuine humility with respect to the transcendence of divine plans, a humility
that should lead one to avoid geocentric or anthropocentric attitudes, thus
respecting the silence of Scripture on the topic. Without placing limitations
on any possible history of revelation or salvation, Delano holds that any of
the three divine Persons could become incarnate on any planet. According to
Delano, such positions are preferable to a sort of “Cosmic Adam,” in which the
single redemptive act of Christ on Earth would apply to the whole universe. In
any case, also according to Delano, a redemptive pluralism does not impede
humans from spreading to other intelligent beings the evangelical message and
the love God shows us. In my opinion, the positions of Mascall and Delano
regarding possible multiple incarnations of the Son or of other divine Persons
seem hardly compatible with a genuine Christian understanding of Revelation, as
it will become clear in the following discussion.
If the preceding considerations underline the flexibility
necessary for a theme such as this, the position of Charles Davis (1960) seems
much better defined. Starting from the biblical data of the cosmic centrality
of Christ with respect to the whole material universe and of his headship over
all creatures, including the angels, Davis concludes that the most correct
theological position should be to maintain the uniqueness of the hypostatic
union (the assumption of human nature by the divine Person of the Son), which
happened only once and only within the context of the earthly economy of
salvation. The consequent privilege for human nature would not be an expression
of anthropocentrism, but the consequence of a coherent Christocentrism. If the
centrality of Christ, the Son of God made man, in the cosmos and in history
were merely the effect of a geocentric horizon present in the modes of
expression used in Scripture, the greater part of our theological understanding
of creation and of our
relationship with God in Christ would inevitably be flawed. To leave the
understanding of the headship of Christ, the God-man, unaltered in a “strong
sense” means to continue to believe that the incarnation of the Word
constitutes the greatest self-communication of God to creation, even against
the background of all other possible creatures. It also means that we humans
must assume the corresponding responsibility. A universe where, on the
contrary, many possible incarnations of the Word would be possible, would no
longer be a Christocentric universe. However, if this were to happen as a
factual event, we would have to conclude that our understanding of Revelation
until that moment had been largely imprecise and even ambiguous. Teilhard de
Chardin holds the centrality of Christ in a strong sense, but at the same time
he stresses the action of a third “cosmic” nature of Christ (a nature other
than the divine and the human natures) and ascribes to it, and not to the human
nature of the Word, the work of recapitulating in Him all creation and all the
beings which participate in it (cf. “La multiplicité des mondes habités,” in Oeuvres,
Paris 1969, vol. X, p. 282). The French author can thus overcome the obstacle
of anthropocentrism, but introduces an element that sounds extraneous to the
commonly accepted Christological dogma, which teaches from the beginning the
presence of only two natures, human and divine, in the divine Person of the
Son-Word (cf. Symbol of Chalcedon [451], DH 300-303).
IV. Christian Theology and Extraterrestrial Intelligence:
Some Possible Approaches
I believe that the theme of possible intelligent life of extraterrestrial
origin, i.e., intelligent life outside the experience of unity of the human
family as presented by the entire biblical message, represents one of the major
speculative efforts facing Christian theology. It would therefore be no
surprise if many questions are perhaps destined to remain unanswered. The only
available analogy for our topic is the study of the relationship between
Christianity and the other religions on Earth, a relatively young discipline,
but one of growing importance in an age of globalization. Without a doubt, the
study of that relationship provides useful guideposts for our problem,
including the salvific universality of the Incarnation of the Word, the
singularity of the hypostatic union, the necessity not to separate the richness
(and in some way the unpredictability) of the creative and salvific action of
the Holy Spirit from the mission and the role of the Son, to whom the Spirit
must necessarily guide. The relationships among the religions of the earth
become generally framed, not without noticeable effort, in what today’s
theology calls “inclusive Christocentrism,” the attempt to re-read other
religions in the light of the mystery of Christ (on this, see the document
issued by the International Theological Commission,Christianity and
Religions, 1997). However, such an analogy only serves as a first approach
to the problem, since the theme of life in the cosmos would supplant the unity
of the human family, created and redeemed in Christ, posing a problem with a
wholly new aspect, as did, for example, the discovery of the American Indians,
about whom Pope Paul III (1534-1549) did not have difficulty to recognize their
belonging to the descendants of Adam (cf. DH 1495). Therefore nothing else
remains for us to do but to approach the problem step by step, recalling some
firm points.
1. The Absence of
Prejudicial Arguments against the “Pluralist” Hypothesis and the Reasonableness
of the “Classical” Position. A first fixed point is that there are no prejudicial
arguments hindering the admission of the “pluralist” position, neither on the
part of the magisterial teaching of the Church nor on the part of theological
reflection. The omnipotent will and unfathomable freedom of God the Creator
continues to imply a valid relevant argument, as does the recognition of the
intrinsic value of life, and in a special way the dignity of intelligent life,
everywhere it is manifested. All life is in some way a participation in and a
reflection of that Life, with a capital “L,” that believers know subsists in
God himself. To these may be added what the Judeo-Christian tradition professes
about the existence of angels. This tradition shows that the meaning of
creation is not completely based on the relationship between man and God, “but
remains open to other creatures,” which, although likewise dependent on God,
have a history and an economy of salvation distinct from that of humankind.
Thomas Aquinas, for example, gave arguments of fittingness to support a very
high number of angels, surpassing any multiplicity of material entities
whatsoever (cf. Summa Theologiae, I, q. 50, a. 3).
Nonetheless, to think that humankind is the only form of
intelligent life in the cosmos would for theology represent a “classical”
position (or a classical solution, as we would say in the language
of physics) and one that would not require the re-interpretation of many
aspects of Revelation . Such a solution is reasonable, and cannot be qualified
as a priori or anti-scientific. Today we know that the very large size of the
physical universe cannot be thought as a sort of “redundancy,” but is linked to
an anthropic necessity: a very large space inevitably corresponds to the long
time necessary for the stellar production of chemical elements indispensable
for life. As a consequence, both the probabilistic argument based upon the
greatness of the cosmos and the theological argument regarding the fittingness
that manifold intelligent beings are created to give glory to God in regions
where man could not do so, are weakened. In an expanding universe —the only one
that could lead to the formation of structures and environments adequate for
life— the long time required for biological evolution necessarily means a large
space and a large amount of matter already formed or in the process of
formation. In this universe it is as reasonable to hold the simultaneous
appearance of many civilizations as it is to hold the existence of only one.
The teleology highlighted by the Anthropic principle does
not indicate conclusions about the multiplicity or the singularity of
intelligent life, but only about the time necessary for its appearance and
about the necessary relationships between life and the structures of the
universe in its entirety. Not knowing the “ultimate reasons” for the origin of
life, science cannot know if life is the result of a categorical imperative or
of a highly improbable event. Consequently, Drake’s or any other Drake-like
equations are of their nature destined to calculate only “necessary”
conditions, but not “necessary and sufficient” conditions for the presence of
intelligent life. In the absence of scientific data that ask theologians for
new solutions within a wider interpretative framework, a theology that wants to
conserve its “classical” solution cannot be charged with unreasonableness on
this account.
2. The Universality of
the Image of the One and Triune God within a Cosmic Context. A second firm
point is that the revealed image of God entrusted to the Judeo-Christian
tradition is not geocentric, nor anthropocentric: it is absolutely universal
and transcendental, subject of a creative omnipotence whose range is without
doubt of cosmic order and certainly not only local. Moreover, the Trinitarian
image of God professed by Christianity also presents itself with universal
characteristics: the existence of a paternity and of filiation, whose
intelligibility is in a sense associated with the generative process common to
every living being, and the existence of a Love-Gift, the Holy Spirit, the
understanding of which refers to the idea of communion, altruism, and donation,
all that is certainly not extraneous to the dynamic of conscious life in
itself, wherever we could know it. This suffices to reject the opinion that
Christian theology, in order to open itself to the possibility of intelligent
life in the cosmos, must inevitably set aside the image of the One and Triune God,
accepting a sort of new “Copernican revolution” that would induce all
civilizations of the universe to cease to recognize their own God, and together
to begin to recognize a common but unknown God, analogously to what some
evangelical authors ask the different religions of the Earth to do today (cf.
J. Hick, The Rainbow of Faiths: Critical Dialogues on Religious
Pluralism, 1995).
Every believer in God would certainly see any eventual meeting
with a non-terrestrial civilization as an extraordinary experience. A believer
would be fundamentally inclined to manifest a sense of respect in such an
encounter, to recognize our common origin and the new possibility of better
understanding the relationship between God and the whole of creation. A similar
encounter, and perhaps the ensuing dialogue, would have a “religious” dimension
in the more natural sense of the term. At the same time, it seems important to
note that a believer who is respectful of the requirements of scientific
reasoning would not be obliged to renounce his own faith in God simply on the
basis of the reception of new, unexpected information of a religious character
from extraterrestrial civilizations. In the first place, human reason itself
would suggest the need to submit this new “religious content” coming from outside
the Earth to an analysis of reasonableness and credibility (analogous to what
we are accustomed to do when any religious content is proposed to us, on
Earth); once the trustworthiness of the information has been verified, the
believer should try to reconcile such new information with the truth that he or
she already knows and believes on the basis of the revelation of the One and
Triune God, conducting a re-reading inclusive of the new data, similar to that
which would be applied in an ordinary interreligious dialogue.
Generally speaking, such contact could not be considered a sort of
“final validation or refusal” of the religious conscience of humanity. Let us
remember that, despite the great majority of terrestrials who believe in the
existence of a Creator of Heaven and Earth, we humans have not supplied any
information of a religious type within the various “messages in a bottle” that
until now have been sent out beyond the solar system (see above, I, n. 1). From
a materialist perspective, the idea that a new entrance into the Galactic
Club will free man from an infantile religious phase and definitely
give us back the awareness of our true place in the universe could be
suggestive, yet in reality is very naïve. The majority of the great existential,
and hence religious, themes pertaining to human life on Earth, such as the
meaning of sorrow and death or
the moral value associated to our free actions, would not be resolved by the
friends of this Club.
3. The Cosmic, and
therefore Creaturely, Headship, of the Mystery of Christ. If the mystery of
the Incarnation refers to a Christocentric headship and not a geocentric one,
then it can be explored and expressed with cosmic and universal, not
necessarily anthropological, categories. The third firm point for our attention
should therefore be the universal, and not only local, revealed and salvific
value of the Incarnation. The headship of Christ, the God-man, over the angelic
creatures (cf Heb 1:3-14 and 2,5-18) would be interpreted as
revealing his headship over all possible creatures (cf Eph 1:10; Col 1:20).
The grandeur of the hypostatic union, which in a sense has an infinite value,
also gives the vicarious sacrifice of Christ an infinite meritorious value. The
way in which this would apply to the whole universe remains a mystery to
Christian theology, but it is enough to state that the efficacy of this
sacrifice does not increase through multiplication. The celebration of the Holy
Mass, for example, applies the fruit of the same historical event to different
times and places without multiplying it. Contrary to what is suggested by other
authors, I believe that a similar participation and efficacy of salvation on a
cosmic plane —where this might be necessary for other intelligent and free
beings— cannot depend on an interplanetary missionary impetus nor upon indirect
communication (although these factors can, and perhaps must, be involved). It
could only depend upon an economy guided by the Holy Spirit, even if accomplished
in a way mostly unknown to us. It is certainly the only economy capable of
securing the universality of salvation and its personal application to each
individual. As in the earthly economy of salvation, the Holy Spirit would still
lead to the Son and would in some way render Him present. This entire
perspective reflects the logical conviction that the Creator has his own ways
to make himself recognized everywhere and to make himself present within his
creatures.
Concerning the personal history of other possible intelligent
beings, responsible for their freedom before God, Father and Creator of
everything (cf Eph 4:6), we humans cannot say anything. We can
affirm, however, that, as creatures, the mystery of Christ, the incarnate Word,
is not extraneous to them. God has assumed in Christ a created nature, a finite
will and freedom, making his own the experience of limits associated with any
creaturely life, an experience that has a value that certainly extends beyond
that of the “human” creature as such. But Christ has also taken onto himself
the reality of death and has revealed its passing, non ultimate character, prefiguring
in his risen body a destiny that belongs to the whole universe and not only to
man. But what resonance or meaning would this have for other creatures of whose
original and originating relationships with God we know nothing? From a
perspective according to which human biological death is a consequence
depending on a direct, total, and exclusive way upon Adam’s original sin, then
Christ’s death seems to have nothing to add to non-human living beings, and
further theological clarifications are expected to improve our understanding of
things. From a perspective that instead leaves greater space for speculation,
understanding death as the end of a cycle that all living creatures based on
thermodynamical processes must necessarily experience, something not
automatically linked to an original sin, then any conscious creature, wherever
it may be, could see death as the place of its acceptance of finitude, of its
being “a creature,” not God. This is nothing but the place of a supreme
experience to which Christ's true death on the cross, like his resurrection,
would have much to say, precisely because of the creaturely humanity he
assumed.
Concerning whether or not the grand theme of the relationship
between sin and freedom may regard the personal history of other beings, I have
already indicated that it is not possible to formulate deductive hypotheses.
However, we are informed that the association between sin and freedom is
verified in the only two cases that theology inductively knows, namely
humankind and angelic creatures. If it is certainly true that sin does not
belong to the perfection of freedom, the possibility of sin seems to be at
least a condition for freedom; and this may render the Christian redemption
less extraneous to any free creatures that did not descend
from the first human beings.
I do not think that the debate regarding extraterrestrial life,
which stands on a purely theoretical basis in the absence of experimental
facts, constitutes the determinate touchstone for a critical evaluation of the
truthfulness and coherence of Christian theology and belief, even if it
represents an extraordinary stimulus to increase the intelligibility of some of
its formulations. As indicated, there exist some fixed points for reflection
and some possible approaches to the question. There exists a “classical”
solution, that of the uniqueness of humankind. In the absence of compelling
proof to the contrary, it would seem incorrect to consider this solution
obsolete simply on the basis of the opening of horizons caused by
contemporary cosmology. A
different, non-classical (in a sense, relativistic) solution would
imply a work of re-understanding that, analogous to what happens in physics
with quantum or relativistic solutions, is required in order to maintain many
of the truths contained in previous classical solutions. The new solution
clarifies that the theoretical framework in which the classical solution can be
applied is narrower than previously known, helping to understand it within a
more general context. The last word on the question of extraterrestrial life
must not come from theology, but from science. The existence of intelligent
life on planets other than Earth is neither required nor excluded by any
theological argument. Theologians, like the rest of the human race,
will just have to wait and see.
Read also:
Bibliography:
Scientific aspects: C.
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