The silent hours steal on ...


King Richard III

The question of all questions for humanity, the problem which lies behind all others and is more interesting than any of them is that of the determination of man’s place in Nature and his relation to the Cosmos. Whence our race came, what sorts of limits are set to our power over Nature and to Nature’s power over us, to what goal we are striving, are the problems which present themselves afresh, with undiminished interest, to every human being born on earth.



AND so at last I return to one of the questions with which I started: the search for extraterrestrial intelligence. While the suggestion is sometimes made that the preferred channel of interstellar discourse will be telepathic, this seems to me at best a playful notion. At any rate, there is not the faintest evidence in support of it; and I have yet to see even moderately convincing evidence for telepathic transmission on this planet.


We are not yet capable of significant interstellar space flight, although some other more advanced civilization might be. Despite all the talk of unidentified flying objects and ancient astronauts, there is no serious evidence that we have been or are being visited.

That, then, leaves machines. Communication with extraterrestrial intelligence may employ the electromagnetic spectrum, and most likely the radio part of the spectrum; or it might employ gravity waves, neutrinos, just conceivably tachyons (if they exist), or some new aspect of physics that will not be discovered for another three centuries. But whatever the channel, it will require machines to use, and if our experience in radioastronomy is any guide, computer-actuated machines with abilities approaching what we might call intelligence.


To run through many days’ worth of data on 1,008 different frequencies, where the information may vary every few seconds or faster, cannot be done well by visually scanning the records. It requires autocorrelation techniques and large electronic computers. And this situation, which applies to observations that Frank Drake of Cornell and I have recently performed at the Arecibo Observatory, can only become more complex-that is, more dependent on computers-with the listening devices likely to be employed in the near future. We can design receiving and transmitting programs of immense complexity. If we are lucky we will employ stratagems of great cleverness and elegance. But we cannot avoid utilizing the remarkable capabilities of machine intelligence if we wish to search for extraterrestrial intelligence.

The number of advanced civilizations in the Milky Way Galaxy today depends on many factors, ranging from the number of planets per star to the likelihood of the origin of life. But once life has started in a relatively benign environment and billions of years of evolutionary time are available, the expectation of many of us is that intelligent beings would develop. The evolutionary path would, of course, be different from that taken on Earth.


The precise sequence of events that have taken place here-including the extinction of the dinosaurs and the recession of the Pliocene and Pleistocene forests-have probably not occurred in precisely the same way anywhere else in the entire universe. But there should be many functionally equivalent pathways to a similar end result. The entire evolutionary record on our planet, particularly the record contained in fossil endocasts, illustrates a progressive tendency toward intelligence. There is nothing mysterious about this: smart organisms by and large survive better and leave more offspring than stupid ones.


The details will certainly depend on circumstances, as, for example, if nonhuman primates with language have been exterminated by humans, while slightly less communicative apes were ignored by our ancestors. But the general trend seems quite clear and should apply to the evolution of intelligent life elsewhere. Once intelligent beings achieve technology and the capacity for self-destruction of their species, the selective advantage of intelligence becomes more uncertain .

And what if we receive a message? Is there any reason to think that the transmitting beings-evolved over billions of years of geological time in an environment vastly different from our own-would be sufficiently similar to us for their messages to be understood? I think the answer must be yes. A civilization transmitting radio messages must at least know about radio. The frequency, time constant, and bandpass of the message are common to transmitting and receiving civilizations. The situation may be a little like that of amateur or ham radio operators. Except for occasional emergencies, their conversations seem almost exclusively concerned with the mechanics of their instruments: it is the one aspect of their lives they are certain to have in common.

But I think the situation is far more hopeful than this. We know that the laws of nature-or at least many of them-are the same everywhere. We can detect by spectroscopy the same chemical elements, the same common molecules on other planets, stars and galaxies; and the fact that the spectra are the same shows that the same mechanisms by which atoms and molecules are induced to absorb and emit radiation exist everywhere.


Distant galaxies can be observed moving ponderously about each other in precise accord with the same laws of gravitation that determine the motion of a tiny artificial satellite about our pale blue planet Earth. Gravity, quantum mechanics, and the great bulk of physics and chemistry are observed to be the same elsewhere as here.

Intelligent organisms evolving on another world may not be like us biochemically. They will almost certainly have evolved significantly different adaptations-from enzymes to organ systems-to deal with the different circumstances of their several worlds. But they must still come to grips with the same laws of nature.

The laws of falling bodies seem simple to us. At constant acceleration, as provided by Earth’s gravity, the velocity of a falling object increases proportional to the time; the distance fallen proportional to the square of the time. These are very elementary relations. Since Galileo at least, they have been fairly generally grasped. Yet we can imagine a universe in which the laws of nature are immensely more complex. But we do not live in such a universe. Why not? I think it may be because all those organisms who perceived their universe as very complex are dead.


Those of our arboreal ancestors who had difficulty computing their trajectories as they brachiated from tree to tree did not leave many offspring. Natural selection has served as a kind of intellectual sieve, producing brains and intelligences increasingly competent to deal with the laws of nature. This resonance, extracted by natural selection, between our brains and the universe may help explain a quandary set by Einstein: The most incomprehensible property of the universe, he said, is that it is so comprehensible.

If this is so, the same evolutionary winnowing must have occurred on other worlds that have evolved intelligent beings.

Extraterrestrial intelligences that lack avian or arboreal ancestors may not share our passion for space flight. But all planetary atmospheres are relatively transparent in the visible and radio parts of the spectrum-because of the quantum mechanics of the cosmically most abundant atoms and molecules. Organisms throughout the universe should therefore be sensitive to optical and/or radio radiation, and, after the development of physics, the idea of electromagnetic radiation for interstellar communication should be a cosmic commonplace-a convergent idea evolving independently on countless worlds throughout the galaxy after the local discovery of elementary astronomy, what we might call the facts of life.


If we are fortunate enough to make contact with some of those other beings, I think we will find that much of their biology, psychology, sociology and politics will seem to us stunningly exotic and deeply mysterious. But I suspect we will have little difficulty in understanding each other on the simpler aspects of astronomy, physics, chemistry and perhaps mathematics.

I would certainly not expect their brains to be anatomically or physiologically or perhaps even chemically close to ours. Their brains will have had different evolutionary histories in different environments. We have only to look at terrestrial beasts with substantially different organ systems to see how much variation in brain physiology is possible. There is, for example, an African fresh-water fish, the Mormyrid, which often lives in murky water where visual detection of predators, prey or mates is difficult.


The Mormyrid has developed a special organ which establishes an electric field and monitors that field for any creatures traversing it. This fish possesses a cerebellum that covers the entire back of its brain in a thick layer reminiscent of the neocortex of mammals. The Mormyrids have a spectacularly different sort of brain, and yet in the most fundamental biological sense they are far more closely related to us than any intelligent extraterrestrial beings.

The brains of extraterrestrials will probably have several or many components slowly accreted by evolution, as ours have.

There may still be a tension among their components as among ours, although the hallmark of a successful, long-lived civilization may be the ability to achieve a lasting peace among the several brain components. They almost certainly will have significantly extended their intelligence extrasomatically, by employing intelligent machines. But I think it highly probable that our brains and machines and their brains and machines will ultimately understand one another very well.

The practical benefits as well as the philosophical insights likely to accrue from the receipt of a long message from an advanced civilization are immense. But how great the benefits and how fast we can assimilate them depend on the details of the message contents, about which it is difficult to make reliable predictions. One consequence, however, seems clear; the receipt of a message from an. advanced civilization will show that there are advanced civilizations, that there are methods of avoiding the self-destruction that seems so real a danger of our present technological adolescence.


Thus the receipt of an interstellar message would provide a very practical benefit that in mathematics is called the existence theorem-in this case the demonstration that it is possible for societies to live and prosper with advanced technology. Finding a solution to a problem is helped enormously by the certain knowledge that a solution exists. This is one of many curious connections between the existence, of intelligent life elsewhere and the existence of intelligent life on Earth.

While more rather than less knowledge and intelligence seems so clearly the only way out of our present difficulties and the only aperture to a significant future for mankind (or indeed to any future at all), this is not a view always adopted in practice.

Governments often lose sight of the difference between short-term and long-term benefits. The most important practical benefits have come about from the most unlikely and apparently impractical scientific advances. Radio is today not only the prime channel in the search for extraterrestrial intelligence, it is the means by which emergencies are responded to, news is transmitted, telephone calls relayed and global entertainment aired. Yet radio came about because a Scottish physicist, James Clerk Maxwell, invented a term, which he called the displacement current, in a set of partial differential equations now known as Maxwell’s equations. He proposed the displacement current essentially because the equations were aesthetically-more appealing with it than without it.

The universe is intricate and elegant. We wrest secrets from nature by the most unlikely routes. Societies will, of course, wish to exercise prudence in deciding which technologies-that is, which applications of science-are to be pursued and which not. But without funding basic research, without supporting the acquisition of knowledge for its own sake, our options become dangerously limited. Only one physicist in a thousand need stumble upon something like the displacement current to make the support of all thousand a superb investment for society. Without vigorous, farsighted and continuing encouragement of fundamental scientific research, we are in the position of eating our seed corn: we may fend off starvation for one more winter, but we have removed the last hope of surviving the following winter.

In a time in some respects similar to our own, St. Augustine of Hippo, after a lusty and intellectually inventive young manhood, withdrew from the world of sense and intellect and advised others to do likewise:

“There is another form of temptation, even more fraught with danger. This is the disease of curiosity. ... It is this which drives us on to try to discover the secrets of nature, those secrets which are beyond our understanding, which can avail us nothing and which men should not wish to learn. ... In this immense forest, full of pitfalls and perils, I have drawn myself back, and pulled myself away from these thorns. In the midst of all these things which float unceasingly around me in everyday life, I am never surprised at any of them, and never captivated by my genuine desire to study them. ... I no longer dream of the stars.”

The time of Augustine’s death, 430 A.D., marks the beginning of the Dark Ages in Europe.

In the last chapter of The Ascent of Man Bronowski confessed himself saddened “to find myself suddenly surrounded in the West by a sense of terrible loss of nerve, a retreat from knowledge.” He was talking, I think, partly about the very limited understanding and appreciation of science and technology-which have shaped our lives and civilizations-in public and political communities; but also about the increasing popularity of various forms of marginal, folk- or pseudo-science, mysticism and magic.

There is today in the West (but not in the East) a resurgent interest in vague, anecdotal and often demonstrably erroneous doctrines that, if true, would betoken at least a more interesting universe, but that, if false, imply an intellectual carelessness, an absence of tough-mindedness, and a diversion of energies not very promising for our survival.


Such doctrines include:

  • astrology (the view that which stars, one hundred trillion miles away, are rising at the moment of my birth in a closed building affect my destiny profoundly)

  • the Bermuda Triangle “mystery” (which holds in many versions that an unidentified flying object lives in the ocean off Bermuda and eats ships and airplanes)

  • flying saucer accounts in general; the belief in ancient astronauts

  • the photography of ghosts

  • pyramidology (including the view that my razor blade stays sharper within a cardboard pyramid than within a cardboard cube)

  • Scientology

  • auras and Kirlian photography

  • the emotional lives and musical preferences of geraniums

  • psychic surgery

  • flat and hollow earths

  • modern prophecy

  • remote cutlery warping

  • astral projections

  • Velikovskian catastrophism

  • Atlantis and Mu

  • spiritualism

  • the doctrine of the special creation, by God or gods, of mankind despite our deep relatedness, both in biochemistry and in brain physiology, with the other animals

It may be that there are kernels of truth in a few of these doctrines, but their widespread acceptance betokens a lack of intellectual rigor, an absence of skepticism, a need to replace experiments by desires. These are by and large, if I may use the phrase, limbic and right-hemisphere doctrines, dream protocols, natural-the word is certainly perfectly appropriate-and human responses to the complexity of the environment we inhabit.


But they are also mystical and occult doctrines, devised in such a way that they are not subject to disproof and characteristically impervious to rational discussion. In contrast, the aperture to a bright future lies almost certainly through the full functioning of the neocortex-reason alloyed with intuition and with limbic and R-complex components, to be sure, but reason nonetheless: a courageous working through of the world as it really is.

It is only in the last day of the Cosmic Calendar that substantial intellectual abilities have evolved on the planet Earth. The coordinated functioning of both cerebral hemispheres is the tool Nature has provided for our survival. We are unlikely to survive if we do not make full and creative use of our human intelligence.

“We are a scientific civilization,” declared Jacob Bronowski. “That means a civilization in which knowledge and its integrity are crucial. Science is only a Latin word for knowledge... Knowledge is our destiny."

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