Extraterrestrial Civilizations (28 page)

This is a much more persuasive argument for the delay in establishing land life than are those involving the capture of the Moon.

It would seem, then, that we must abandon the thought of the Moon’s playing a crucial role in the development of civilizations. Whether a habitable planet has a large satellite, a small satellite, a captured satellite, several satellites, or no satellites should not affect, as nearly as we can judge from the evidence on hand,
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the development of land life, and intelligence will move on undisturbed.

Then where is everybody?

Granted, then, that there are as many habitable planets as we have estimated and that all of them are filled with land life, can we really be sure that an intelligent species will inevitably arise on each of them?

Are we perhaps wrong to apply the principle of mediocrity to this phase of the calculations? Can it be that the development of intelligence on Earth is an unbelievably lucky chance, and that while the Galaxy and the Universe swarm with life, even with land life, intelligence and, hence, civilizations might be be altogether absent—except here?

Are the requirements for an intelligent species all but impossible to meet? What are they?

In the first place, an intelligent species must be rather large, for it must develop a large brain; though it must not be too large, in the sense that its body must not outrun its brain.

Thus, the human being is more intelligent than its larger relative, the gorilla; and undoubtedly more intelligent than the still larger (and now extinct) Gigantopithecus, the largest primate that ever lived, as far as we know.

Nevertheless, the human being is one of the four largest primates now existing, and those four are all more intelligent than the smaller primates from the gibbon downward. What’s more,
Homo sapiens
, the species that is the brightest of the hominids, is also the largest.

Of the nonprimate mammals the most intelligent are the elephant and the dolphin, and they are large animals, too. The octopus, which is the most intelligent of the invertebrates, is among the larger invertebrates; and the crow, which may be the most intelligent of the birds, is among the larger birds.

This very largeness must be one of the reasons for the delay in the establishment of intelligence on Earth (and, presumably, on any similar planet), since it must take considerable time for the blindchance processes of evolution to develop a species large enough to house a brain large enough for the purpose.

What makes it even more difficult is that the brain is by far the most complexly organized of all the tissues, so that it is far easier, so to speak, to develop additional mass and intricacy in any of the
tissues other than the brain. Therefore, there are many more large-bodied, small-brained species than large-bodied, large-brained species.

Might not the difficulty of producing a large body with a large brain be so great as to preclude it in almost every case?

Of course, we might argue that intelligence offers such advantages that the tendency toward it would be overwhelming. After all, it is our intelligence that grants human beings security against any form of life large enough, armed enough, vicious enough to demolish us if we were not intelligent. No mighty predator can stand against us. Indeed, we must make a special effort to avoid extinguishing the proudest and most magnificent species in existence—and despite all our efforts we may fail. The power of our intelligence is too great to soften and make mild.

Let us, however, not be misled by our pride. Our intelligence is not an all-encompassing advantage. There are disadvantages, too. Since an intelligent organism must be relatively large, it must also be relatively few in numbers. It must be long lived, to take advantage of its intelligence (for if it dies before it has learned much, its intelligence goes for nothing), and it must therefore reproduce comparatively slowly.

If an intelligent species must then compete with other species, which, not being intelligent, can afford to be small, numerous, fecund, and short lived, the intelligent species labors under a serious disadvantage. There is every reason to think that evolution hands the award (survival) to the quality of fecundity more than to anything else.

The intelligent species has young that are few and that are quite helpless until the extraordinarily complex brain, which cannot reach adequate growth even during an extended stay as fetus, develops sufficiently. If something happens to the young organism before it can in turn reproduce, it represents the loss of an enormous investment of time and effort (both biological and social).

A tiny unintelligent species can produce thousands or even millions of eggs, which will quickly hatch out myriads of young that can live independently of their parents. Most will be eaten, but the investment for any one of them is negligible, and some will surely survive.

What’s more, to be short lived and fecund is to evolve at breakneck speed. The insects, which are the most familiar example of short-lived, fecund organisms, have evolved into more species than make up all noninsect organisms put together, and by any standard other than that set by our own vanity are the most successful group of organisms in the world.

Nor can humanity, at its present peak of intelligence and technology, defeat the insects. We can effortlessly destroy elephants and whales, but the insects, who consume large fractions of our food supply, defy us. We can kill them by the billions, but there are always more to replace the dead. If we use poisons, those few that happen to be able to resist the poison survive and at once breed billions of others, all equally resistant. We use brains, they use fecundity, and they win.

As a matter of fact, if you leave human beings to one side, other intelligent species are even less successful. Neither the gorilla nor the chimpanzee is a very successful species. Certainly neither can match the rat when it comes to making its way through a hostile world. Nor is the elephant as successful, to all appearances, as the rabbit; nor the whale as the herring.

Might we argue, then, that intelligence is essentially an evolutionary blind alley? Might we argue that, on the whole, the disadvantages outweigh the advantages until some critical level is reached and passed that will allow the intelligent species to assert at least some spectacular forms of domination over the world?

Perhaps that critical level is so difficult to reach, through and over the disadvantages of intelligence generally, that it was obtained by the hominids on Earth only through an extraordinary fluke which is duplicated nowhere else.

All this, however, does not carry conviction.

As we survey evolution on Earth, there does seem a trend in the direction of increasing size and complexity (occasionally overdone, to be sure, to the point of diminishing returns). What’s more, increasing complexity seems almost always to involve increasing intelligence in widespread groups of living things.

Even among the insects, at least three groups—ants, bees, and termites—are social insects. Instead of growing into large and complex individuals, they remain small, but form large and complex societies;
and the societies seem considerably more intelligent as a whole than are the small individual organisms that make it up.

If intelligence increases in the development of many different groups of species, and even does so in two widely different ways—the elaboration of the individual and the elaboration of the society—then we have to assume that sooner or later some developing intelligence will pass the critical level.

The weight of evidence, as presently known, therefore forces us to consider that intelligence, and sufficient intelligence to produce a civilization, is more or less an inevitable development on a habitable planet, given sufficient time.

And still we’re thrown back to that same question. If we can’t find any reason to deny the development of hundreds of millions of civilizations in our Galaxy, why is everything so quiet? Why has not one of them made itself known to us?

The answer may lie in the fact that so far we have only specified that so many civilizations have come into being. We have not yet asked the question as to how long a civilization may endure once it has come into being.

This is an important point. Suppose that each civilization that comes into being endures only a comparatively short time and then comes to an end. That would mean that if we could examine all the habitable planets in the Universe, we might find that on a large number of them civilization has not yet arisen, and that on an even larger number civilization has arisen, but has already become extinct. Only on a very few planets would we find a civilization that has arisen so recently that it has not yet had time to become extinct.

The briefer the duration of civilizations, on the average, the less likely we are to encounter a world on which the civilization has come and not yet gone, and the fewer civilizations
in being
there will be now—or at any given moment in the history of the Universe.

Might it be, then, that civilizations are self-limiting, and that the reason civilizations elsewhere have not made themselves known to us is that they don’t endure long enough to be heard from?

Is there reason to suppose that civilizations might be short lived? Unfortunately, judging from the one civilization we know—our own—the task of finding reason is all too easy.

Our own civilization has a dubious future, and if we can express the reason in brief it is that we find it difficult (perhaps impossible) to cooperate in solving our problems. We are too contentious a species and apparently find our local quarrels to be more important than our overall survival.

In a way, all living things must be contentious. Reproductive capacities are such that any species, reproducing freely, can in short order outrun its food supply, however plentiful.
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Consequently, in the case of any species there will always be a race for food among themselves. The competition may not be direct and need not involve confrontation, and yet the survival of some will mean (and is dependent on) the nonsurvival of others. Even plants compete vigorously and remorselessly for sunlight.

The danger to civilization, then, is not just that human beings are contentious, but that they are far more contentious than other species. For this we can see several reasons, every single one having to do with intelligence—which is unfortunate, for it may mean that all species capable of building a civilization must be perforce overly contentious.

For instance, thanks to their intelligence, human beings are more apt than any other species to understand that competition exists. For human beings it is not just the striving for the immediate scrap of food, or the guarding of an immediate kill. For human beings, it is the working out of a long-range scheme for getting the better of others.

In other species, a quarrel over food will last until one individual succeeds in swallowing it, whereupon the other individual disappointed, moves away to seek something else. There is no point in fighting and striving once the food is gone.

For the intelligent human beings, capable of forethought and
therefore understanding what death by starvation means and how likely it might be at a given time, a quarrel over food is more likely to be violent and of long duration, and to end in serious injury and death. What is more, even if one individual is beaten and driven off without serious injury to himself, and the food is eaten by the victor, the fight may not be over.

The human being is intelligent enough to hold a grudge. The loser, remembering the injury to his own chances of survival, may then strive to kill the winner by trickery, or from ambush, or by rallying friends—if he cannot do it by main force. And the loser may do this not for any direct good it will do him, or for any increase in the chance of his survival, but out of sheer anger at the memory of the harm done him.

It is not likely that any species other than the human being kills for revenge (or to prevent revenge, since dead people tell no tales and plot no ambushes). This is not because human beings are more evil than other animals, but because they are more intelligent than other animals, and can remember long enough and specifically enough to give meaning to the concept of revenge.

Furthermore, to other species there is little else but food, sex, and the security of the young over which to quarrel. In the case of the human being, however, with his intelligent capacity for foreseeing and remembering, almost any object is liable to set off a spasm of competitive acquisitiveness. The loss of some ornament, or the failure to seize one, may set up a grievance that will lead to violence and death.

And, as civilization approaches and is achieved, human beings develop a more and more materialistic culture, one in which the possession of any number of different things is held to be of value. The development of hunting makes stone axes, spears, bows, and arrows valuable. The coming of agriculture gives land a much greater value than ever before. Rising technology multiplies possessions, and almost anything—from herds of animals, to pottery, to bits of metal-can be equated with economic well-being and social status. Human beings will then have reasons without number to attack, defend, maim, and kill.

Furthermore, the advance of technology cannot help but increase the power of the individual human being to commit effective violence. It is not just a matter of choosing to manufacture swords
rather than plowshares. To be sure, some products of technology are designed to kill, but almost
any
product can be used to kill if the anger or fear is there. A good heavy pot, ordinarily used for the most peaceful purposes, can be used to crush a skull.

This continues without limit. Human beings now have at their disposal a series of weapons deadlier than they have ever had, and they still strive for a further intensification of deadliness.

We can conclude that it is impossible for any species to be intelligent without coming to understand the meaning of competition, to foresee the dangers of losing out in competition, to develop an indefinite number of material things and immaterial abstractions over which to compete, and to develop weapons of increasing power that will help them compete.