The aim of those men who created the upheaval in the seventeenth century, which we now call the "Scientific Revolution" was not the conquest of Nature, but the understanding of Nature. "Yet their cosmic quest destroyed the medieval vision of an immutable social order in a walled-in universe together with its fixed hierarchy of moral values, and transformed ... the society, culture, habits and general outlook as thoroughly as if a new species had arisen on this planet."*

The aim of SETI is not to conquest but to understand either. We cannot even guarantee success in a trivial, superficial sense (that is in the form of the discovery of an alien civilization). But at its deeper levels SETI certainly stimulates and influences our thoughts and transforms our society:

• SETI is a logical, essential extension of the current Origins Program;
• SETI is a basic source of the understanding of our position and fate in the universe;
• SETI has a matchless unifying power for all mankind and it is a potential powerful tool to create a peaceful, really planet-wide civilization;
• The SETI paradigm has brought to us not only substantially new perspectives but can help bridge intellectual gulfs and creates a most suitable place where the two terrestrial cultures (the scientific and the literary) meet.

This contribution offers a compact survey of the items described above and in addition to this lays special stress on the interdisciplinary benefits of SETI in the field of social and political sciences.
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* Quotation from A. Koestler (The Sleepwalkers, Preface).

Copyright  2000 by the International Astronautical Federation or the International Academy of Astronautics. All rights reserved.
 
 

As far as the first item (NASA's Origins Program) is concerned, it is known that basically as a reaction against exaggerated subservience to the Copernican principle, Carter¹ in the early seventies introduced the so called anthropic principle, which in its weak form declares that we must be prepared to take into account the fact that our location in the universe is necessarily privileged to the extent of being compatible with our existence as observers. Now, if it turns out that ETI exists and the case of mankind is not exceptional, the final step of the Copernican revolution is done: the place of the Earth is not central even in the sense of harboring intelligent life.

It was disillusioning for us to learn, that the Earth goes around the Sun, that there are other suns, other galaxies, maybe other universes. It was humbling when we discovered that we are descended from inferior animals. But now we can cherish some definite hope to have highly developed extraterrestrial "kinsfolk" somewhere outdoors.

Simply our body provides the best indication. Evolution and natural selection is supposed to provide for adaptive demands and even so curiously had equipped homo sapiens with an organ - our brain - which (utilizing only two or three per cent of its capacity) he was unable to put to proper use up to the present day. Since evolutionary genetics is incapable to explain this oddity, there is a chance that at least a part of our genetic code is not of local origin and just the success of SETI - giving us a comparison with other intelligent beings - can finally throw light on the origin of this seeming paradox. (If e.g. some kind of the so called panspermia² theory is involved it will greatly improve the likelihood that - similarly to us - at least some intelligent ET societies will try to contact and understand each other, because they would have kindred genetics.)

Turning our attention to the second item (which is closely related to the first one) there is absolutely no doubt about it that the detection of an ETI signal would arouse a wide-ranging public interest and would initiate vivid philosophical and theological discussions as well. Long-lasting non-detection on the other hand would certainly raise the issue of the loneliness, uniqueness of our civilization or at least the extreme scarcity of ETI's in our Galaxy, albeit it seems inconceivable that we will ever prove ourselves to be alone in the universe. (This question takes us beyond the limits of science. As a consequence of Kurt Gödel's incompleteness theorem³, knowledge can't be both perfect and grounded in something else. The laws of science - and therefore all scientific inferences - are grounded in the physical world; hence they can never be entirely unquestionable.)

Ever since Aristarchus became conscious of the vastness of the cosmos, either Ptolemy thought that we are at its center or Copernicus cleared we are not, people have widely accepted the possibility that other worlds house other intelligent beings.^4,5 Even prominent representatives of the Catholic Church did not exclude the existence of other worlds. "Do there exist many worlds, or is there but a single world? This is one of the most noble and exalted questions in the study of Nature" - wrote St. Albertus Magnus around 1260.

Other representatives of the church, who think that we are unique, frequently quote St. Thomas Aquinas, who argued that separate similar worlds would be in vain and would not be consistent with divine wisdom. And if dissimilar, none of them would be perfect, and an imperfect world could not be the work of a perfect Creator. Here they overlook an obvious fallacy: God have created billions of human beings; they are all different and nobody is perfect.

The conviction in the 'plurality of worlds' is generally based on three beliefs: on the so-called "principle of plentitude" which declares that what can exist must exist everywhere where the conditions are suitable for it; on the "principle of mediocrity" which takes for granted that our existence is noting out of the ordinary*, and on the "infinity of the cosmos" which - on the by-condition that the laws of nature are everywhere the same - assures that any event with non-zero probability must occur unlimited times in the universe.

It is obvious that in support of the first two principles SETI is of basic importance. "There is no stronger army in all the world than an idea whose time has come" wrote Victor Hugo in 1870, and the time for the scientific foundation of the "plurality of worlds" and the intensive search for extraterrestrials has certainly come. During the last years quite a number of prominent opponents of SETI have changed their minds. The most peculiar case is the one of Frank Tipler who as lately as in 1980 still took the view that "extraterrestrial intelligent beings do not exist"⁶ and in 1997 published a remarkable book on his W-Point-Theory⁷, the most important presupposition
(*Compare with the remark of Sagan and Newman: "We do not possess any uniquely valid locale, epoch, velocity, acceleration, or means of measuring space and time."⁸⁾ of which is the anthropic principle in its sharpest form as final anthropic principle claiming that "life and intelligent life are not only necessary within our universe, but can also no more disappear after their first emergence. Rather they are destined to pervade and dominate the entire universe."

It is impossible not to see that the final anthropic principle combined with the principle of mediocrity is a firm argument in support of SETI. Another even more important consequence is - according to Wolfhard Pannenberg, one of the greatest theologians of the 20^th century - that Tipler's scientific cosmology can be seen as an approximation of scientific theory to the subject matter of Christian theology and leads to the theological consequence that God in his capacity as creator and final future of the universe draws his creatures into communion with himself by way of the history and evolution of the universe.⁹

As appears from the foregoing, the frequently raised question on the pure existence of ETI's is not a suitable one; only the frequency of occurrence in a well defined region (e.g. in a stellar system) of the universe can be treated by scientific methods. In the discussion of the number (N_c) of technological civilizations in our Galaxy two general forms of the well-known Drake equation have been widely used (see f.i.¹⁰). For our purpose Cameron's formulation is the more proper one, according to which

                                                              N_c = N_s f_s L_c/L_p ,                                                                   (1)

where N_s is the number of potentially suitable parent stars, f_s is a compound selectivity factor, L_c is the length of the communicative phase of a society and L_p is the part of the lifetime of a planet during which highly developed species can exist on it. The estimates for most of these factors
have not altered to any significant degree since the memorable Green Bank conference in 1961. But if we accept the idea that the longevity of a civilization might be limited with high probability by catastrophic events threatening during the crossing of galactic arms, intelligent life is presumably concentrated in a belt in the Galaxy which is a narrow annulus including the so called co-rotation circle and the galactic orbit of our Sun.

If the "galactic belt of intelligent life"¹¹ is a reality, the first and last factors in Eq. (1) must be reconsidered. As far as N_s is concerned, only stars in the belt can be regarded. The volume of the ring is ~ 6 kpc³, the stellar density ~ 0.13 pc^-3_, and only 10 % of the stars have long-lasting habitable zones¹⁰, so N_s is only about 8 x 10⁷! L_p can also be judged by astronomical methods. It is basically limited by the evolution of the parent stars, and by the crossing time that a planetary system spends between two spiral arms.

An estimate for L_c is beyond the reach of conventional astronomical methods. It is not accidental, that by far the most controversial issue of the entire equation is that of L_c. The proposed values markedly depend on our global situation of the moment. Accordingly a rather pessimistic figure of 10 years was accepted at the Green Bank conference, at a time, when the cold war and the threat of a fatal nuclear exchange just got to their culminating point. Albeit the value of L_c can now rightly be increased from 10 to at least 40, the only hopeful possibility to forecast our far future with any reasonable probability is provided uniquely by the success of SETI. Using routine values for the other three factors of the Drake equation, if the next neighbors of the galactic community would be f.i. only a few hundred light years away, roughly 1 % of the developing technical civilizations would make long lasting peace with themselves and survive for centuries or perhaps for millennia.

As touching the third item, we have to keep in mind, that the factors that influence human responses include attributes of individuals and characteristics of their environmental background. In the short run, reactions to an ETI signal detection can strongly vary from flat unconcern through moderate positive or negative curiosity, through flaming enthusiasm or mortal anxiety to serious persecution complex or on the contrary to full scale pronoia (thinking that the universe is simply a conspiracy on our behalf). The danger is to be reckoned with that in certain circles the first contact will lead to a certain kind of anomie that is to a specific social instability resulting from a sudden breakdown of traditional standards and values.

In addition, some people are afraid that as a consequence of receipt of comprehensive, encyclopedic information from an alien civilization, our science would become useless in its present-day form. Taking into account that we are only at the beginning of our technical civilization, any intelligent life form that we detect in a SETI experiment is statistically likely to be significantly older than the human race, and if so their knowledge is likely to have advanced to a much higher level. Accordingly, rather than doing traditional science, it would be much more practical to try to decipher and comprehend the alien encyclopedia. In point of fact, our scientists will have become theologians: interpreters of a cosmic 'Bible' handed down by superior beings.
But this is certainly, at the worst, only a short-term effect. Surely the century following the detection of a comprehensive alien 'message' will be marked by the attempt of our experts to understand it and to reconcile terrestrial and extraterrestrial knowledge. Based on instructive analogues from the history of science (and on the capacity of our brain), there is no cause for anxiety. We should rather wonder, "if terrestrial and extraterrestrial knowledge will be mutually exclusive, coexist with minimum interaction, or blend to become part of a long-sought objective knowledge." ^12,13

I am convinced that in the long run the positive effects will dominate and perhaps none of them is more important than the unequalled unifying power for all mankind. The search for ETI represents the first step involving us in cosmic politics (giving politics a higher purpose). We are witnessing the gradual emergence of an ethos of the Earth. "That ethos may be one of the foundations of the conception of the (human) species as a political entity." ¹⁴ Here on the earthly proscenium we are playing our roles as Americans, Germans, Hungarians etc.; but on the all embracing cosmic stage we are purely and simply humans, just one minority of the galactic community, irrespectively of the possibility of a direct physical contact between its members or - come to that - of the present-day existence of a "galactic wide web". Our realm of consciousness and mental activity - our noosphere - will surely expand, bringing about the unambiguous realization of our global cultural relatedness.

Entering upon the fourth item, C. P. Snow was already in the late fifties of the opinion that the breakdown of worthwhile communication between the sciences and humanities (the "two cultures") was a major obstacle to solving the world's problems.¹⁵ E. O Wilson has recently complained of the separation of the natural sciences, social sciences and humanities and argued for "consilience" - the proof

To sum it up, besides achieving consilience, the following sorts of long- term consequences of a successful ETI contact are particularly likely to result: ¹⁸

• advanced practical information (ET societies may have broadcast advice, knowledge, values, principles of political organizations etc.);
• new insights of certain major - and locally unanswerable - questions (e.g. destructively aggressive species will inevitably eliminate themselves ® our fate?);
• a transformation in our view of ourselves and our place in the universe (see the first three items of this paper);
• the final victory of the extraterrestrial paradigm (our long-term future will be determined by extraterrestrial ventures and contacts).