The Cultural View of Life in the Universe Some cultural questions The phenomenon of life brings up many questions. When answers to these questions are likely to have strong implications on the dynamics of human culture they are deemed "cultural" questions. They may affect our feelings with respect to the world at large and influence religious creed and behaviour. We here consider some of these questions. The recent exploration of the Universe has reduced our planet Earth to an a priori very modest level. It has left the centre on the Universe, which it had in the Ptolemaic system, to become one of the telluric planets near an average star that is located at an average place in the outskirts of a galaxy, which hosts a hundred billion stars, and which itself is part of a visible Universe with about a hundred billion galaxies. We are no longer the centre of the Universe and there could be very many planets similar to ours. This unremarkable location in space is accompanied by an average location in time: the Solar System came into being 5 billion years ago in a Universe, which was already 10 billion years old. It is expected to disappear as such 5 billion years from now, when our Sun will become a red giant and then a white dwarf. Thus, we do not happen to live at a special time in the history of the Universe. But our planet may still be special, because it is harbouring life. Life, at least in some primitive form, seems to have appeared almost as soon as crust formation and surface temperature on the Earth made it possible, i.e., about 3 billion years ago. Since that time, life seems to have evolved in complexity and sophistication following a natural drive filling all possible ecological niches. There seems, therefore, to be nothing particularly special to life as long as (or perhaps rather: as soon as) proper conditions are satisfied. Yet, life may, indeed, be very special and unique to the Earth. This leads us to an already old cultural question: how unique is our planet? When one considers the evolution of life on Earth, the importance of historical accidents (or choices made by nature) is compelling. The complex organisation of molecules that it implies has made specific choices, which could have been different, and they appear to have been made once and for all. One is surprised by the universal properties of life with its using about twenty amino acids only to build proteins and only four bases for the genetic coding. It is, of course, natural that the self-replicating mechanisms, which are fundamental to life impose the successive choices that become lasting once they have been made and proven working. One is nevertheless amazed by the uniqueness of the selected genetic mechanism and also by the unique way through which life collects, transports and uses energy. By searching for life in the Universe, one may discover other biological choices, which could have been made elsewhere through different historical developments. This brings a second cultural question: how unique is the manifestation of "our kind of life"? Life in its simplest form seems to be associated with a complex organisation of entities, set up in such a way as to allow the life-preserving activities, namely selfbuilding (metabolism) and reproduction (genetics). This is the case even for the simplest organisms such as viruses and bacteria. This may be called the first form of life but there may be even simpler forms, although it is hard to conceive it without both achieving success with metabolism and recording that success. In a more elaborate form, cell association and differentiation and the complexity of the interplay between different elements permits sophisticated reactions from individuals. When associated with pattern-recognition and analysis, such capabilities lead to advantageous actions. This is most efficient when associated with a central nervous system as it is in the elaborate forms of the animal kingdom, which appeared on Earth in the last billion years. This may be called the second form of life. It covers an extreme variety with increasing sophistication brought by evolution. We encounter here a crucial cultural question: was evolution purely Darwinian and based on trial and error, or was it guided by some finality currently beyond our understanding? Finding other evolutionary patterns elsewhere could bring some clues. From our point of view, the most complex and powerful achievement is the human mind with its ability to analyse complex patterns, but also to develop feelings and formulate abstract concepts. The manifestations, which single us out in the animal kingdom and shape our culture, are religion, art and science, with different emphasis in different cultures. This intelligent form of life may be called the third form of life and with it we meet the key cultural question: is intelligent life unique? When considering life in the Universe one should face these three stages of development, which could naturally follow, or not, from one another and the question "how strong and efficient is the drive for evolution toward greater complexity?" comes back. In facing these questions and looking for information, one should always keep in mind that nature is most probably richer than our imagination. Searching for the first two forms of life (virus type and complex organisms) requires closer observations in situ and/or sample collection. We live at a particularly interesting time when such close observation 'on location' and sample collection is becoming possible on planets and comets. This kind of observation will, however, for the time being be limited to the Solar System. But, even here, there are already fascinating candidates to explore, such as Mars, Europa and Titan, together with comets. In parallel with that, we live at a time when the search for planets of distant stars is being much rewarded. The existence of many planets, which, in principle, are able to sustain life, may soon become a fact. We shall know how frequently this situation occurs and we can then apply statistics at the level of the Universe. This will much better shape our views on how likely we think it is, to eventually find life elsewhere. The distances involved will, however, exclude close observation or sample gathering - given that the closest star is 4 light years away! Searching for the third form of life - with intelligent beings with whom we could communicate (or to whom we could at least 'listen') - may, therefore, be the only way where we have a hope to collect evidence since, indeed, it is highly likely that we are the only intelligent beings in the Solar System. Searching for life Searching for the first form of life (up to viruses and bacteria) This form of life already requires the inter-connection of elaborate organic (carbon-based) molecules and the presence of water. This is already highly complex but it seems that, despite this complexity, this form of life appeared very quickly on the young Earth. Recent infrared studies have shown that water is almost everywhere in the Universe and complex organic molecules have already been found in space. It may thus be that the appearance of life on Earth could have been made possible by the collection of already complex molecules. Since comets brought water, they may also have brought elements of life and created a brew. This makes sample-return missions to comets particularly interesting. Following along the same line, one should not be surprised to find similar forms of life in the Solar System or at least traces (fossils) that show that life has existed. Primeval organisms on Earth are very resistant and adaptable. It may thus be surprising, if they did not appear elsewhere, where water and energy of solar or telluric origin had been available. Wouldn't it rather be a surprise that life would exist on Earth only? Searching for more complex forms of life The occurrence of more complex forms of life requires the relatively rapid evolution of complex adaptable systems with cell specialisation. On Earth this includes sexual production, which strongly speeds up the effects of beneficial mutations seen in a Darwinian perspective. It is amazing that all living organisms use the same biochemical procedures and hard to understand, why evolution has selected only one winning scheme. One is, on the one hand, amazed by the efficiency and ingenuity of the life-sustaining mechanisms, which have been singled out during evolution, and, on the other hand, surprised by the high redundancy of the many systems working in parallel and by the tremendous loss in survival, which is anticipated in the reproduction process. This makes life in general highly resistant to even hostile environments, although the best-adapted forms at any given time may be fragile vis-à-vis a rapid change of conditions in the environment (which may lead in some cases to rapid extinction). Another key cultural question is, whether or not a more evolved form of life exists. Such a form of life would work with different biochemical schemes than those found on Earth, i.e., in a situation, where evolution has made different, yet more efficient choices. This would elucidate the role of the historical component in the evolution of complex organisms and lead to a better understanding of how nature gradually builds up through evolution of highly elaborate adaptable systems. It may, however, be that the time needed for such an evolution, which requires favourable conditions, sustained over hundreds of millions of years, could have been available only on our Earth within the Solar System, because other celestial bodies have been submitted to too strong and rapid environmental changes. Searching for intelligent life This is the realm of the Drake formula which multiplies mostly unknown and yet numerous probabilities. This is a fascinating cultural question, which almost compulsively leads us to collecting and deciphering possible signals from outer space. A dinosaur has little to say about prime numbers. This brings us to the question (included in one of Drake's probabilities) of how long a civilization can survive, once it masters Maxwell's equations and disposes of enough power for long distance radio communications. We have had fifty years of it only, as compared to the evolution of life on Earth of over 3 billion years! We can take an optimistic attitude and work on the basis of tens (or hundreds?) of million years for the lifetime of humankind but then, in view of the tremendous number of stars in the Galaxy, many of them much older than the Sun, one cannot avoid asking the question: "If they exist at all, why haven't they showed up already?" The silence of the outer world is a surprise. It would be strange, if we were the most advanced civilization in the Universe! We are completely in the dark on that matter but, looking to deep space, one should do that with an open mind and also consider intelligence, which would not use carbon-based life, as beautifully illustrated by Fred Hoyle in his book "The Dark Cloud". It would be a tremendous cultural happening to receive a message. Carl Sagan has very well illustrated this in his book "Contacts". We can but hope that these aliens, if they exist at all, will be better disposed with respect to humans than humans have often been in the past with respect to less advanced civilizations on Earth. The impact on religion In an essay on "Art and Science", Victor Weisskopf spelled out two cardinal values of humankind, namely knowledge and compassion, adding, "Without knowledge compassion is not efficient but without compassion, knowledge is not human." All religions face these two human quests and endeavours, compassion being better expressed by the Greek word "Agape". God is a concept that puts itself beyond human intelligence but one can at least recognise different images associated with God, which can then be better grasped. There is God the creator (the almighty God) who made the world, a world left to us to discover and understand and there is the God of compassion (sometime even the suffering God) helping us distinguishing good from evil and a companion through prayer across the ups and downs of human life, which depend so much of inter-human relations. This second and anthropocentric facet of God is actually the one, which is most deeply rooted in all religions, while recognizing of course that compassion exists irrespective of any specific religious belief. Religions attempt to bring harmony between humans and harmony between humankind and the Universe. In the latter case they have adapted easily to the fact that the Earth is not central in the Universe as most naturally assumed in genesis composed several thousands years ago. In the context of these highly simplifying remarks, one may say that discovery of life in a rather primitive form elsewhere in the Solar System would not appreciably affect religious feelings. There is no limit for the creation of God and one can but admire it. The discovery of advanced intelligence elsewhere in the Universe would however shake the very special relation, which some religions herald between God and the human race, and would then have a tremendous impact on religious beliefs. However religion, in its quest for harmony, could then help in our accepting a more modest view of our place in the Universe and one may hope that it could also help us avoiding paranoia while developing more compassion with our fellow humans.