La vida en el universo. ¿Qué sabemos sobre el pasado y el futuro del mundo?

Life in the Universe: What do we know about the past and future of the world?

Author: Mariano Artigas
Published in: Aceprensa, 167/94
date of on-line publication: 14 December 1994

On the occasion of its 150th birthday, Scientific American magazine dedicates a monographic issue to examine current knowledge about the evolution of the universe and the prospects for the future.1and presents it as a "multimedia extravaganza", accompanied by a video and special offers for industry and Education.

Today's science presents us with a world that has been formed in successive stages since the initial Big Bang. Scientists are at agreement on the broad lines, disagree on many particular problems, and raise, with varying degrees of success, philosophical and theological questions about the world and mankind.

Cosmic evolution

The Big Bang model is in excellent health. Scientists admit that the universe formed from a primordial state in which all the subject and energy were concentrated in a small space, with an enormous temperature. The main evidence for this model is now classic, and well established: the background radiation that was first measured in 1964 and is like a fossil of events that took place when the universe was only 300,000 years old, the relative abundance of the light elements (hydrogen, helium, etc.) in the universe, the age of the components of the universe.

Doubts remain about the age of the universe, which is usually estimated to be between 10 and 20 billion years old. We are now being told that, according to some estimates, it could be between 12 and 16 billion, and according to others, between 8 and 11 billion. And a new uncertainty is added: globular clusters are between 12 billion and 18 billion years old; they could therefore be older than the universe! However, these uncertainties and possible paradoxes do not baffle scientists, who are used to readjusting the figures when new knowledge demands it.

Nothing is known about what existed and what happened in the very first moments. Only very conjectural hypotheses are available that cannot, for the moment, be tested experimentally. Perhaps the Big Bang was the result of an earlier evolution of the universe, but current science is not in a position to propose plausible answers. It is certainly possible that the Big Bang did not coincide with the absolute origin of the world, and some even say that it may have been an event that affected only a part of a larger universe.

It is claimed that in the early universe there were only light elements, from which stars and galaxies were formed by gravitational condensation. The heavier elements, such as carbon, iron and so many others, would have formed in the interior of stars, in the reactions that take place there at enormous temperatures, and would then be dispersed in the explosion of supernovae. Although the training of the Solar System remains unknown, it is claimed that the Earth originated about 4.5 billion years ago.

The general outline of this cosmic evolution is generally accepted. And science tells us nothing about creation or the meaning of the universe, which are metaphysical and religious problems. The four authors of the article on the evolution of the universe, who are leading astrophysicists, recognise this when they state that our universe can be viewed from different perspectives, such as those of the mystic, the theologian, the philosopher, or the scientist. They are right. These perspectives are different and complementary.

Biological evolution

Biological evolution is also in excellent health. There is complete unanimity among biologists about the "fact" of evolution. The discrepancies, which are by no means small, concern the particular "mechanisms" or explanations of evolutionary processes.

The discrepancies mainly concern the origin of life on Earth. However, the "RNA world" hypothesis, according to which RNA or ribonucleic acid molecules would be the precursors of the living organisms we know, because they could have the capacity to catalyse their own replication (a task currently entrusted to proteins), is currently gaining ground. This is the opinion of Leslie E. Orgel, author of the corresponding article, although he points out the not inconsiderable difficulties and unknowns of this hypothesis and any other hypothesis that attempts to scientifically explain the origin of life.

But there are also discrepancies when it comes to explaining the successive evolution of living organisms. In his article on this topic, Stephen Jay Gould argues that Darwinian natural selection must be supplemented by other factors: it is insufficient to explain evolution because there are other important factors (neutral genetic mutations, evolutionary leaps, mass extinctions), and also because evolution, being a singular and very complex historical event, includes many elements that cannot be summarised in a general theory. We do not even know how almost all the fundamental plans of living things originated in the explosion of the Cambrian period some 530 million years ago: Gould claims that this phenomenon was the most B and mysterious event in the history of life.

When we come to man, we again find multiple unknowns. In an interview in the same magazine, Mary Leakey, who made three central discoveries in African hominid history (in 1948, 1959 and 1978), says that topic is very difficult, and goes so far as to say that discussions of topic are a good "mental exercise" that can become ridiculous if taken too heatedly.

William H. Calvin writes about "the emergence of intelligence", and focuses on the factors that make the existence of our intelligence possible. He rightly stresses the importance of language and the logical capacities that language implies, and summarises current knowledge about the brain, experiments with chimpanzees, and the relationship of language to our motor skills. But it is clear that the existence of our peculiar abilities raises many questions.

At final, there remain many mysteries whose solution is far from straightforward. However, this does not preclude a general consensus among biologists about the general outline of evolution and its fundamental milestones.

Extraterrestrial intelligence and robots

Carl Sagan writes a article on the search for extraterrestrial life, and Marvin Minsky another in which he asks: will robots inherit the Earth? The ideas of both authors are well known, as is the somewhat nebulous nature of their speculations. Although these articles are written in scientific language, the reader will notice that much of their content could be categorised as science fiction.

Sagan recalls that on 12 October 1992, on the occasion of the 500th anniversary, NASA embarked on a new project search for extraterrestrial intelligence, which was cancelled a year later by the US congress and will now be resurrected using private funds. The topic is certainly interesting, but very difficult: the fastest signal sent to the nearest star takes more than four years to get there.

Minsky, of M.I.T., aligns himself with Hans Moravec, an enthusiastic advocate of the "children of our mind", i.e. the robots that (according to the author) will come to surpass and eventually replace us. And, incidentally, he insinuates that we will be able to achieve earthly immortality by replacing the parts of our organism that need it, although he recognises that it is not at all easy and, furthermore, that the people with whom he has discussed it do not seem too enthusiastic about this prospect.

These two articles are significant because they show the ease with which quite fanciful things can be said in a serious scientific journal. The prestige of science is so high B that, as long as they are presented in scientific garb, the most picturesque ideas can be defended. Personally, I am struck by the enormous superficiality that the materialist Sagan displays in his books when he tackles philosophical or religious problems, as well as his enthusiasm, not very scientific, for extraterrestrial life. And when I read Moravec's book to which Minsky refers (his degree scroll is "Mind Children"), I was left with a doubt that I have not been able to clear up: whether the author is serious or whether his book has, from beginning to end, a certain air of a joke.

Science and naturalism

At final, we find the status typical of current discussions: the central scientific problems are dealt with at a very good level, the logical discrepancies between scientists on many issues are noted, and from time to time, depending on the idiosyncrasies of the different authors, we come across philosophical or theological problems that are dealt with very unevenly: sometimes correctly, sometimes unhappily.

The current status is paradoxical. On the one hand, everyone recognises the limits of science and the legitimacy of other approaches to reality. But when it comes down to it, some scientists (not all, not the majority, but some who make a lot of noise) seem to assume that everything is possible for science and that, on the contrary, nothing is possible for other perspectives.

Naturalism" enjoys a certain diffusion, especially in intellectual circles. It is an old pretension, which wants nothing to do with "supernatural" causes and presents science, without reason, as if scientific progress meant the elimination of everything connected with God: creation, the divine plan and its government of the world, human spirituality. Sometimes the spiritual dimensions and metaphysical problems are simply ignored: this is the case, for example, when the "emergence of human intelligence" is spoken of as if it were a problem that could be solved by purely scientific means. At other times, we witness a real confrontation with metaphysical problems, and not exactly in the right way. Let us look at a few examples.

Man's place in the cosmos

Gould begins his article on evolution with a truly unique paragraph. He says that some creators announce their interventions with great apparatus, like God, who said "Let there be light" and the universe appeared, while others make great discoveries in a modest way, as Darwin did when he defined the mechanism of evolution in 1859. Leaving aside the possible irreverence of comparing God with Darwin (Gould will know what his intention is), it is clear that Gould opposes, from the beginning, divine creation and scientific evolution. Throughout his article, he insists time and again that man is the result of a very complex process that includes much chance and is unpredictable: he wishes to emphasise that we are an accidental result of evolution, which might not occur if evolution were to repeat itself. And he claims that this implies a conceptual revolution that we have not yet assimilated. Then, to top it all off, he finishes with a biblical quotation from the book of Wisdom.

Gould's message seems to be this: since science cannot predict the results of evolution, we are an unpredictable, accidental result , and our existence does not respond to any divine plan. But the reasoning is very weak from the point of view of Philosophy and theology. Indeed, a God who is truly the First Cause of everything does not need scientific equations or anything like that for his plans to be realised. Moreover, God does not necessarily create: in affirming God's existence, we must also affirm that human existence is contingent, that is, that we might not have existed. Finally, that the divine plan is compatible with contingency or accidentality, and even seems in some way to require it, is an affirmation that (like the previous ones), is found at least in Thomas Aquinas, in the 13th century.

Of course, ancient philosophers and theologians knew little about evolution, but Gould seems to know even less about Philosophy and theology. Something similar is true of Steven Weinberg who, in his introductory article , points out in passing that there is no evidence for a plan in the origin and evolution of life. Weinberg is award Nobel in physics for his work on electroweak theory, but that has nothing to do with his previous statement. Like Gould, he would do well to mind his own business. It is clear that science alone will never allow us to affirm that there is a divine plan, any more than it allows us to deny it. Science does provide a lot of material for philosophical reflection on the problem, but to seriously address it requires a philosophical and theological perspective: science alone is not enough.

A new Galileo case?

I do not think it is risky to say that we are now facing a new Galileo case, only the other way round. The theologians made a mistake in the Galileo case by meddling where no one was calling them, trying to solve problems that belonged to skill of science. Now something similar is happening, but in reverse and in a big way. Some scientists quietly invade the terrain of Philosophy and theology, pontificating on issues that science cannot resolve.

The analogy is not my invention. I heard it from a Nobel Prize winner, award , who said that scientists today have the social prestige that priests used to have. This is partly true. The academic community has an enormous social weight, and it also has the means of speech that did not exist centuries ago. Its opinions reach every citizen, and make quite an impression. It should seriously reflect on the attitude it takes to questions that cannot be solved by science alone. Otherwise, it could provoke an intellectual and social contamination that would dwarf the famous Inquisition.

My first vocation was science. I have always loved science, and I love it now. I think it is one of the main achievements of mankind. Precisely for this reason, I am repulsed when I see science, its prestige, its achievements, used as an instrument to invade other fields, without respecting the legitimate autonomy of each perspective. I understand that Sagan, Gould, Weinberg and other scientists live in the United States and there they meet some fundamentalist Protestant groups who sometimes attack science, Bible in hand. But they should realise that this is partly a reaction to the excesses of some scientists.

In any case, it is a pity that, at this point in time, when there is a generalised worldwide agreement on the differences and complementarity of science, Philosophy and religion, there still appear, in serious publications of undoubted prestige, blunders that sow confusion. It is more understandable that this happens in some well-known journals that seem to be too concerned with selling. Perhaps if scientists and journals would just tell it like it is, leaving science to say only what it can say, they would sell less. That may well be. But science has its justification as a search for truth and as an instrument in the service of man. And those who work in or around science should not lose sight of that. Personally, I believe in God, in the spirituality of man, in the afterlife, in the existence of a divine plan, and all this does not detract from my interest in science: on the contrary, I suspect that I enjoy it much more than Weinberg, Sagan, Minsky or Gould, and I have no doubt that I discover in science depths and lights that cannot be seen by those who think we are a mere accident of nature. Not even Paul Davies thinks this any more, which is saying something!


(1) This is issue of October 1994. In Spanish, it corresponds to issue of December 1994 of research y Ciencia.