Broca's Brain: The Romance of Science

other beings on our planet. The sure lesson of evolution is that organisms elsewhere must have separate evolutionary pathways; that their chemistry and biology and very likely their social organizations will be profoundly dissimilar to anything on Earth. We may well be able to communicate with them because we share a common universe-because the laws of physics and chemistry and the regularities of astronomy are universal. But they may always be, in the deepest sense, different. And in the face of this difference, the animosities that divide the peoples of the Earth may wither. The differences among human beings of separate races and nationalities, religions and sexes, are likely to be insignificant compared to the differences between all human and all extraterrestrial intelligent beings.

If the message comes by radio, both transmitting and receiving civilizations will have in common at least a knowledge of radiophysics. The commonality of the physical sciences is the reason that many scientists expect the messages from extraterrestrial civilizations to be decodable-probably in a slow and halting manner, but unambiguously nevertheless. No one is wise enough to predict in detail what the consequences of such a decoding will be, because no one is wise enough to understand beforehand what the nature of the message will be. Since the transmission is likely to be from a civilization far in advance of our own, stunning insights are possible in the physical, biological and social sciences, in the novel perspective of a quite different kind of intelligence. But decoding will probably be a task of years and decades.

Some have worried that a message from an advanced society might make us lose faith in our own, might deprive us of the initiative to make new discoveries if it seemed that others had made those discoveries already, or might have other negative consequences. This is rather like a student dropping out of school because his teachers and textbooks are more learned than he is. We are free to ignore an interstellar message if we find it offensive. If we choose not to respond, there is no way for the transmitting civilization to determine that its message was received and understood on the tiny distant planet Earth. The translation of a radio message from the depths of space, about which we can be as slow and cautious as we wish, seems to pose few dangers to mankind; instead, it holds the greatest promise of both practical and philosophical benefits.

In particular, it is possible that among the first contents of such a message may be detailed prescriptions for the avoidance of technological disaster, for a passage through adolescence to maturity. Perhaps the transmissions from advanced civilizations will describe which pathways of cultural evolution are likely to lead to the stability and longevity of an intelligent species, and which other paths lead to stagnation or degeneration or disaster. There is, of course, no guarantee that such would be the contents of an interstellar message, but it would be foolhardy to overlook the possibility. Perhaps there are straightforward solutions, still undiscovered on Earth, to problems of food shortages, population growth, energy supplies, dwindling resources, pollution and war.

While there will surely be differences among civilizations, there may well be laws of development of civilizations which cannot be glimpsed until information is available about the evolution of many civilizations. Because of our isolation from the rest of the cosmos, we have information on the evolution of only one civilization-our own. And the most important aspect of that evolution-the future-remains closed to us. Perhaps it is not likely, but it is certainly possible that the future of human civilization depends on the receipt and decoding of interstellar messages from extraterrestrial civilizations.

And what if we make a long-term, dedicated search for extraterrestrial intelligence and fail? Even then we surely will not have wasted our time. We will have developed an important technology, with applications to many other aspects of our own civilization. We will have added greatly to our knowledge of the physical universe. And we will have calibrated something of the importance and uniqueness of our species, our civilization and our planet. For if intelligent life is scarce or absent elsewhere, we will have learned something significant about the rarity and value of our culture and our biological patrimony, painstakingly extracted over 4.6 billion years of tortuous evolutionary history. Such a finding will stress, as perhaps nothing else can, our responsibilities to the dangers of our time: because the most likely explanation of negative results, after a comprehensive and resourceful search, is that societies commonly destroy themselves before they are advanced enough to establish a high-power radio- transmitting service. In an interesting sense, the organization of a search for interstellar radio messages, quite apart from the outcome, is likely to have a cohesive and constructive influence on the whole of the human predicament.

But we will not know the outcome of such a search, much less the contents of messages from interstellar civilizations, if we do not make a serious effort to listen for signals. It may be that civilizations are divided into two great classes: those that make such an effort, achieve contact and become new members of a loosely tied federation of galactic communities, and those that cannot or choose not to make such an effort, or who lack the imagination to try, and who in consequence soon decay and vanish.

It is difficult to think of another enterprise within our capability and at a relatively modest cost that holds as much promise for the future of humanity.

PART V. ULTIMATE QUESTIONS

CHAPTER 23

A SUNDAY SERMON

Extinguished theologians lie about the cradle of every science as the strangled snakes beside [the cradle] of Hercules.

T. H. HUXLEY (1860)

We have seen the highest circle of spiraling powers. We have named this circle God. We might have given it any other name we wished: Abyss, Mystery, Absolute Darkness, Absolute Light, Matter, Spirit, Ultimate Hope, Ultimate Despair, Silence.

NIKOS KAZANTZAKIS (1948)

THESE DAYS, I often find myself giving scientific talks to popular audiences. Sometimes I am asked to discuss planetary exploration and the nature of the other planets; sometimes, the origin of life or intelligence on Earth; sometimes, the search for life elsewhere; and sometimes, the grand cosmological perspective. Since I have, more or less, heard these talks before, the question period holds my greatest interest. It reveals the attitudes and concerns of people. The most common questions asked are on unidentified flying objects and ancient astronauts- what I believe are thinly disguised religious queries. Almost as common-particularly after a lecture in which I discuss the evolution of life or intelligence-is: “Do you believe in God?” Because the word “God” means many things to many people, I frequently reply by asking what the questioner means by “God.” To my surprise, this response is often considered puzzling or unexpected: “Oh, you know, God. Everyone knows who God is.” Or “Well, kind of a force that is stronger than we are and that exists everywhere in the universe.” There are a number of such forces. One of them is called gravity, but it is not often identified with God. And not everyone does know what is meant by “God.” The concept covers a wide range of ideas. Some people think of God as an outsized, lightskinned male with a long white beard, sitting on a throne somewhere up there in the sky, busily tallying the fall of every sparrow. Others-for example, Baruch Spinoza and Albert Einstein-considered God to be essentially the sum total of the physical laws which describe the universe. I do not know of any compelling evidence for anthropomorphic patriarchs controlling human destiny from some hidden celestial vantage point, but it would be