24. Scientists Views of ET Life: Since World War II, Part I
Serious speculation about extraterrestrial life outside our solar system is often thought to be a new development, something not common until after World War II. That was indeed when science returned to the beliefs of an earlier period, often without being aware of those past beliefs. What happened? We do not have any more evidence for ET life than we ever had. Some, especially biologists, still dont think it exists, and those who do, and take interest in exobiology, are often accused by their colleagues of endorsing a science without any subject matter. Yet in the 1970s when I wrote The Planet-Girded Suns, belief not only in ET life but in the existence of civilizations more advanced than ours was shared by over 90% of scientists as well as a majority of laymen. (Since then the pendulum has begun to swing again, as Ill explain in the next lecture.)
Part of the reason for scientists return to speculation about ETs was that the accidental theory of planetary formation was abandoned in the 1940s. It was found that many of the features of the solar system couldnt be accounted for by the tidal hypothesis, and that objections formerly raised to the nebular hypothesis werent valid. (Though I can remember being taught both in school, in 1946, as competing theories.) Furthermore, discovery that some nearby stars have dark companions made the odds of system formation depending on near-collisions virtually incalculable. Still another factor was observation of the rotation of stars, which suggested that those spinning slowly had planets. Astronomer Frank Drake reports having heard the eminent astrophysicist Otto Struve explain these discoveries in 1951, saying In the space of a few moments in a lecture hall, Struve had raised the number of planets in the Galaxy we knew about to more than ninety-nine billion. Since then, all theories have assumed that formation of planets is a natural part of stellar evolution, in no way unusual; solar systems are no longer assumed to be rare.
The origin of life, however, is still thought to depend on accidental processes. Although its generally believed that primitive forms of life will arise on all planets where appropriate conditions exist, biology assumes that each step of evolution leading to a higher form depends on random mutation. The probability of the sequence of such mutations that led to our own species is, according to most calculations, extremely low, and the majority of biologists who have written on the subject have rejected the idea that a comparable sequence may occur frequently.
What was it, then, that made astronomers so apt to share the publics interest in ET civilizations? It was the development of a potential means of communicating with those civilizations: radio astronomy. No longer was the subject of alien life one on which there was no hope of obtaining data. From tbe time the search for extraterrestrial radio signalsnow known as SETIwas first proposed in 1959, optimism about it grew. A 1972 National Academy of Sciences report stated that More and more scientists feel that contact with other civilizations is no longer something beyond our dreams but a natural event in the history of mankind that will perhaps occur in the lifetime of many of us. I suspect that last phrase, in the lifetime of many of us, was in many cases the key to their optimism about the existence of ETs.
I wont go into the scientific aspects of SETI here; if youre not familiar with them, there are many good books about it. [And also many websites.] Whats more relevant to this course is the fact that the scientists who support SETI advance exactly the same views of ETs as the rest of Space Age mythology, and theyre equally dependent on mythopoeic thinking. Im not saying this as criticismafter all, I approve of mythology and believe its vital to our culture. But if anyone is under the impression that there are real scientific arguments for the conviction that ETs are sending signalsas opposed to the fact that we can probably detect and interpret such signals if they existthen all he or she needs to do is to read books on SETI in the light of what weve been discussing in the course.
The Gods from Outer Space view not only is prevalent among SETI enthusiasts, it has been specifically used to obtain funding from Congress. When Senator Proxmire gave the project one of his infamous Golden Fleece awards and almost got it killed, Carl Sagan was able to convince him, in Drakes words, that if such societies had lived through their nuclear age, then we could tooby their example, or perhaps their instruction. Drake himself has much higher hopes. He says, I fully expect an alien civilization to bequeath us vast libraries of useful information ... Another, even more stirring Renaissance will be fueled by the wealth of alien scientific, technical, and sociological information that awaits us ... I suspect that immortality may be quite common among extraterrestrials ... when I look at the stars twinkling in the sequined panorama of the night sky, I wonder if, among the most common interstellar missives coming from them is the grand instruction book that tells creatures how to live forever.
I am not saying this may not be true, or that SETI isnt a good idea (though as readers of my novels know, I personally believe that advanced civilizations do not contact less advanced species, on the grounds that it interferes with their evolution). The point here is that SETIand as a result, perhaps public interest in spaceis fueled not by rational thought but by nonfiction expressions of Space Age mythology. This amplifies the importance of that mythology to our culture.
Drake, the father of SETI in this country, developed an equation over 30 years ago that is still used for estimating the probable number of communicating civilizations in our galaxy, and is included in most astronomy textbooks. The factors in it are rate of star formation, fraction of stars that form planets, number of planets hospitable to life, fraction where life actually emerges, fraction where life evolves into intelligent beings, fraction capable of interstellar communication, and length of time such a civilization lives. Putting something into mathematical form always gives the illusion of reliabilitybut its obvious that this is a case of garbage in, garbage out. If even one of those factors is way off, the result is going to be totally meaningless, and we dont have any real data about any of them, or even any theoretical predictions except in the case of the first two. The last one, L (longevity of intelligent civilizations) is particularly speculative. Iosif Shklovsky, who led SETI in Russia and co-authored a book with Carl Sagan about it, changed his mind about its prospects late in his life, to the dismay of American friends who were no longer in communication with him. After his death, they learned what had happened: Shklovsky had gotten depressed about our global political situation and changed the value of L in the equation.
It goes without saying that all the arguments about the probable actions of
ET civilizations depend on personal opinion, not on any knowledge whatsoever
of alien beings actual motivations. Drake is absolutely certain that
they would not develop interstellar travel because, even if it should become
possible, it would be too expensive in energy, and why transport physical
bodies between stars when it is so much easier to transport information?
(One longs to ask him why he himself doesnt stay home and communicate
with foreign scientists online instead of traveling around the world to
meetings, as he has done many times.) On the other hand, there are now some
who believe that interstellar travel is so common that ET civilizations
dont bother with radio messages. Neither side in this debate will
admit that intelligent species may not all act in the same way,
let alone the way that seems reasonable to certain humans. It is not a
scientist, but New Age writer Terence McKenna, who has pointed out, To
search expectantly for a radio signal from an extraterrestrial source is
probably as culture-bound a presumption as to search the galaxy for a good
Thirty years (as of 1995) ago, most scientists believed that interstellar travel is not possible. Since this view has been revised, there has been a trend toward still another change of mind about ETs existence, based on the surprise some feel that we havent met any. Back in the 1940s, physicist Enrico Fermi posed the question, Where are they? He, like more recent speculators, was convinced that if any such civilizations are older than ours (as some should be if Earth is an average planet as predicted by the assumption of mediocrity) then they should have arrived here by now. Of course, many possible reasons have been suggested as to why they havent, including the possibility that they have indeed come here without revealing themselves. Drake thinks they colonize only their own solar systems (using ONeill colonies). I think theyve deliberately concealed their presence, or else long ago passed this system by when they saw the possibility of evolution here. Some think our solar system is simply not interesting to them. Nevertheless, a minority of speculators agreed with Fermi all along (Paul Levinson was one who did) and beginning in the 80s, more scientists adopted views similar to his. As in the case of emotionally-based estimates of SETI success, I suspect that emotion influenced some of their arguments.
Why would anyone not want to believe in ETs, when the evidence from history and from Space Age mythology clearly shows that most people do want to? Perhaps some are unconsciously dismayed by the idea of contact with our superiors. Then too, there have been a few scientists who were clearly upset by funding being diverted to SETI rather than to their own specialities. But a far more frequent factor, I think, is that there have always been people who are attracted by the idea that Earth has unique significance in the scheme of things. Whewell, in the 1850s, seems to have felt that way, and belief in our spiritual centrality now takes a new form: some of todays serious thinkers feel that humans of Earth must bear the full responsibility for spreading life throughout the galaxythat we ourselves are destined to fill the mythic role of gods.
Marshall Savage, for instance, writes in his recent book The Millennial Project, We are not just an insignificant species of semi-intelligent apes, charged only with the welfare of ourselves, or even of our little planet. Rather, we are the sole source of consciousness in an otherwise dead cosmos. It is all up to us... We few, we happy few, must decide the destiny of a universe. Savage frankly labels a subsection, Gods R Us, and while others with comparable views display less hubris, its perhaps significant that they seem to be people who dont respond to myths of Gods from Outer Space or even the Force. Theres certainly nothing bad about a conviction that we should participate in creation by bringing life to dead worldsafter all, we have no real evidence that the rest of the universe wont indeed remain lifeless if we fail to act. Still, the crusading spirit that generally accompanies this idea is stronger than can be accounted for by rational thought alone.
Furthermore, views such as these do not seem to be the main reason for the recent signs of a lessened scientific consensus. Another factor that may be contributing to it is discouragement about SETIs not having produced resultsalthough its really far too soon to expect any. A more important one may have to do with speculation about the potential of interstellar travel in our own future. It is now recognized that interstellar travel should be possiblenot necessarily faster-than- light travel, which most scientists still consider a violation of physical law, but space arks or at least interstellar probes that could carry human genetic material. Some believe, as I do, that its imperative for us to colonize other solar systems, if only to escape the eventual death of our sun. But if civilizations more advanced than ours havent visted our world, then (I suspect) it looks as if its not possible after all! Isnt it less discouraging, therefore, to believe that there arent any such civilizations? Nobody comes out and says this. But the emotional tone of some of the arguments, and their use of speculative premises as if they were unquestionable, suggests that theres more going on than objective reasoning.
The person who has written most about how ETs absence proves their nonexistence is cosmologist Frank Tipler. In The Anthropic Cosmic Principle (Oxford, 1988), co-authored with John Barrow, he states categorically that if they existed, they would be here, on the basis of calculations that show interstellar travel would automatically lead to the colonization of the entire galaxy in less than 300 million years. The ironic thing about Barrow & Tiplers discussion is that I wholly agree with some of itunlike most of whats written about ETs, its based on the premise that colonization of space is necessary to a sentient species survival. I do not, however, agree that this means colonization of every single solar system in the galaxy! They cite objections to this idea and demolish them rapidly on the basis of nothing but their opinion. They state that the saying absence of evidence is not evidence of absence does not apply to our not having met any ETs because, they claim, we do have evidence of their absence, and then cite only evidence that UFOs arent alien ships. They say not likely yet argue as if those words meant absolutely beyond belief (as do many biologists). Though their conclusions about ETs are not accepted by the majority of scientists, the Where are they? argument does have more adherents than it did in the 60s and 70s. Despite my strong advocacy of interstellar colonization, I still see no validity in it.
One other factor is contributing to a revival of the belief that Earth is unique, and thats a recent cosmological idea called the Anthropic Principle, which says that the universe has to be the way it is because if it werent, we wouldnt be here to observe it. This is too complex to go into here, but basically, it denies the assumption of mediocrity. It reveals that what were in a position to observe isnt just chance and therefore probably typical, because what we observe is what did lead to our own existence. Barrow and Tiplers book is an excellent discussion of the history and implications of this principle; their application of it to evolution of ETs, however, is debatable. And the chapter on interstellar travel gets far from scientific cosmology. Like most other discussions of ET life by scientists, its an attempt to reason logically from premises that are essentially mythopoeic.
Again, I must emphasize that I dont mean these observations in a negative way. Rather, they are an illustration of the fact that a cultures outlook on the universe is inseparable from its mythology, and that mythopoeic thought, as well as rational thought, is essential to scientific progress. We need mythic ideas about the mysterious; without them, we wouldnt feel strongly enough to pursue new avenues. If we were limited to opinions based on evidence, we would never take the steps that move us ahead. And its good, too, that our mythopoeic convictions often conflict with each otherfor if they didnt, our civilization might head toward a dead end.
This may be hard for science-oriented individuals to accept, at least as far
as our present mythic ideas are concerned. And yet, with respect to the
past, scientists and technicians are often the first to acknowledge it.
Its quite common for them, in fact, to attribute their achievements in
space science to their early interest in science fiction.