Extraterrestrial Civilizations (3 page)

Anatomical distinctions were sought, some little bodily structure that might be present in human beings alone and not in other animals, and most particularly not in apes. None has ever been found.

In fact, the superficial resemblance between ourselves and other primates, and in particular between ourselves and the chimpanzee and gorilla, becomes all the deeper on closer examination. There is no internal structure present in the human being that is not also present in the chimpanzee and gorilla. All differences are in degree, never in kind.

But if anatomy fails to establish an absolute gulf between human beings and the most closely related nonhuman animals, perhaps behavior can do so.

For instance, a chimpanzee cannot talk. Efforts to teach young chimpanzees to talk, however patient, skillful, and prolonged those efforts may be, have always failed. And without speech, the chimpanzee remains nothing but an animal. (The phrase
dumb animal
does not refer to the lack of intelligence of the animal, but to its muteness, its inability to speak.)

But might it be that we are confusing communication with speech?

Speech is, we may take for granted, the most effective and delicate form of communication of which we are aware, but is it the only one?

Human speech depends upon human ability to control rapid and delicate movements of throat, mouth, tongue, and lips, and all this seems to be under the control of a portion of the brain called Broca’s convolution, named for the French surgeon Pierre Paul Broca (1824–1880). If Broca’s convolution is damaged by a tumor or a blow, a human being suffers from aphasia and can neither speak nor understand speech. Yet such a human being retains intelligence and is able to make himself understood, by gesture for instance.

The section of the chimpanzee’s brain equivalent to Broca’s convolution is not large enough or complex enough to make speech in the human sense possible. But what about gesture? Chimpanzees use gestures to communicate in the wild; could that use be improved?

In June 1966, Beatrice and Allen Gardner of the University of Nevada chose a one-and-a-half-year-old female chimpanzee they
named Washoe and decided to try to teach her a deaf-and-dumb language of gestures. The results amazed them and the world.

Washoe readily learned dozens of signs, using them appropriately to communicate desires and abstractions. She invented new modifications, which she also used appropriately. She tried to teach the language to other chimpanzees and she clearly enjoyed communicating.

Other chimpanzees have been similarly trained. Some have been taught to arrange and rearrange magnetized counters on a wall. In so doing, they showed themselves capable of taking grammar into account and were not fooled when their teachers deliberately created nonsense sentences.

Young gorillas have been similarly trained and have shown even greater aptitude than chimpanzees.

Nor is it a matter of conditioned reflexes. Every bit of evidence shows that chimpanzees and gorillas know what they are doing, in the same sense that human beings know what they are doing when they talk.

To be sure, the ape language is very simple compared to the language of human beings. The human being is enormously more intelligent than apes, but again the difference here is one of degree rather than kind.

To anyone considering the comparative intelligence of animals, it is clear that the key anatomical factor is the brain. Primates have larger brains in general than the large majority of nonprimates, and the human brain is the largest primate brain by a good deal.

The brain of an adult chimpanzee weighs 380 grams (13½ ounces) and that of an adult gorilla weighs 540 grams (19 ounces or just under 1¼ pounds). In comparison, the brain of an adult male human being weighs on the average 1,450 grams (3¼ pounds).

The human brain is not, however, the largest that has ever evolved. The largest elephants have brains as massive as 6,000 grams (about 13 pounds) and the largest whales have brains that reach a mark of 9,000 grams (nearly 19 pounds).

There is no question but that the elephant is among the more
intelligent animals. In fact, the intelligence of the elephant is so apparent that human beings tend to exaggerate it. (There is a greater tendency to exaggerate the elephant’s intelligence than the ape’s, perhaps because the elephant is so different from us in appearance that it represents a lesser threat to our uniqueness.)

We do not have the opportunity to study whales as we do elephants, but we may readily believe that whales are among the more intelligent animals, too.

Yet, although elephants and whales are relatively intelligent, it is quite clear that they are far less intelligent than human beings, and may well be less intelligent than the chimpanzee and gorilla. How may this be squared with the superhuman size of their brains?

The brain is not merely an organ of intelligence; it is also the medium through which the physical aspects of the body are organized and controlled. If the physical size of the body is great, enough of the brain is occupied with the physical to allow little for the purely intellectual.

Thus, each pound of chimpanzee brain is in charge of 150 pounds of chimpanzee body, so that the brain-body ratio is 1:150. In the gorilla, the ratio may be as low as 1:500. In the human being, on the other hand, the ratio is about 1:50.

Compare this with the elephant, where the brain-body ratio is as little as 1:1,000 and the largest whales, with as little as 1:10,000. Now it is not so surprising that there is something special about human beings that the large-brained elephants and whales do not seem to duplicate.

Yet there are organisms in which the brain-body ratio is actually more favorable than in the human being. This is true for some of the smaller monkeys and for some of the hummingbirds. In some monkeys the ratio is as great as 1:17.5. Here, though, the absolute mass of the brain is too small to carry much of an intellectual load.

The human being strikes a happy medium. The human brain is large enough to allow for high intelligence; and the human body is small enough to allow the brain space for intellectual endeavor.

Yet even here the human being does not stand alone.

In considering the intelligence of whales, it is perhaps not fair to deal with the largest specimens. One might as well try to gauge the intelligence of primates by considering the largest member, the gorilla, and ignoring its smaller cousin, the human being.

What of the dolphins and porpoises, which are pygmy relatives of the gigantic whales? Some of these are no more massive than human beings and yet have brains that are larger than the human brain (with weights up to 1,700 grams, or 3¾ pounds) and more extensively convoluted.

It is not safe to say from this alone that the dolphin is more intelligent than the human being, because there is the question of the internal organization of the brain. The dolphin’s brain may be organized for predominantly nonintellectual purposes.

The only way to tell is to study dolphin behavior, and here we are sadly hampered. They seem to communicate by modulated sounds even more complicated than those of human languages, yet we can make no progress in understanding dolphin communication. They seem to show signs of intelligent behavior, even kindly and humane behavior, yet on the other hand their environment is so different from ours that it is difficult for us to get inside their skin and grasp their thoughts and motivations.

The question of the exact level of dolphin intelligence remains, at least for now, moot.

In the light of the previous sections of this chapter, the question as to whether nonhuman intelligence exists on Earth must be answered: Yes.

It would seem that my contention early in the chapter that science has made us alone has not been demonstrated. There are a number of animals with surprisingly high intelligence, and these include not only apes, elephants, and dolphins. Crows are surprisingly intelligent when compared with other birds, and octopi show a level of intelligence far surpassing that of other invertebrates.

And yet absolute differences
do
exist; unbridgeable gulfs
are
there. The clue lies not so much in the mere presence of intelligence but in what is done through the use of that intelligence.

Human beings have been defined as tool-making animals and, to be sure, even the small-brained hominids who were our precursors were already making use of shaped pebbles a couple of million years ago. This is not surprising, since even the small-brained hominids had
brains that were rather better than those of the apes of today.

However, other animals, even some who are quite unintelligent, make use of stones and twigs in ways that can only be considered as tool using.

It is not, then, tool making in itself that establishes a clear gulf between the human being and other intelligent animals.

And yet there may be some one kind of tool that marks the clear boundary line separating the most intelligent species from all others.

We have not far to seek. The key lies in the taming and use of fire. There is definite evidence of fire’s having been used in caves in China in which an earlier hominid species,
Homo erectus
, dwelt at least half a million years ago. The discovery has never been forgotten.

No human society existing anywhere on Earth now lacks the knowledge of how to ignite and use a fire. No nonhuman species whatever has ever made the slightest advance in the direction of the use of fire, as far as we can tell.

Suppose we define “human intelligence” as: A level of intelligence high enough to allow the development of methods for igniting and using fire.

In that case, to the question of whether the equivalent of human intelligence exists on Earth in nonhuman species, the answer must be: No! —The human being stands alone.

This might seem unfair; and the result of an arbitrary, self-serving definition. Let’s see if it is by comparing the dolphin and the human being.

The dolphin spends his life in water and the human being spends his life in air. Water is a viscous medium, much more viscous than air. It takes much more effort to force one’s way through water at a given speed than it does through air. (Anyone who has tried to run when partly immersed in water knows this is so.)

In order to attain speed in water, the dolphin has evolved a streamlined form to reduce water resistance. Moving through air, however, the human being does not require streamlining. The human being can develop a very irregular form and still be capable of fast motion.

For that reason, the human being can develop complicated appendages, while the dolphin cannot. The dolphin’s streamlining allows it two stubby paddles and a fluke as its only maneuverable appendages, and these are useful only for propulsion and guiding.

To put it most briefly, human beings, because they live in air, can develop hands with which they can manipulate their environment. Dolphins, because they live in water, cannot develop hands.

Then again, the fire that early humans learned to handle is the radiation of heat and light that results from a rapid energy-yielding chemical reaction. The most common energy-yielding large-scale chemical reactions that are useful in this connection are those resulting from the combination of substances containing carbon atoms, hydrogen atoms, or both (“fuel”) with the oxygen in the air. The process is called combustion. Fire cannot exist under water since free oxygen is not present and combustion cannot take place.

Therefore, even if dolphins had the intelligence to conceptualize fire, and to work out, mentally, the steps needed to tame and use it, they would be unable to put any of it into practice.

We see now, however, that the human use of fire could be considered as no more than the accidental by-product of the fact that the human being lives in air, and is not in itself necessarily a true measure of intelligence.

The dolphins, after all, even though they are unable to manipulate the environment and unable to build and use a fire, may have in their own way developed a subtle philosophy of life. They may have worked out, more usefully than we have, a rationalization of living. They may interchange more joy and good will with their feelings and understand more. The fact that we cannot grasp their philosophy and their modes of thought is no evidence of their low intelligence, but is perhaps evidence of our own.

Well, perhaps!

The fact is, though, that we don’t have any evidence of the dolphin’s philosophy of life. The lack of that evidence may be entirely our fault, but there’s nothing we can do about it. Without evidence, there is no way of reasoning usefully. We can look for the evidence and someday, perhaps, find it, but until then, we can’t reasonably assign human intelligence to the dolphin.

Besides, even if our definition of human intelligence on the basis of fire is unfair and self-serving on some abstract scale, it will prove useful and reasonable for the purposes of this book. Fire sets us on a road that ends with a search for extraterrestrial intelligence; without fire we would never have made it.

The extraterrestrial intelligences we are looking for, then, must
have developed the use of fire (or, to be fair, its equivalent) at some time in their history, or, as we are about to see, they could not have developed those attributes that would make it possible for them to be detected.

Throughout the history of life, species of living creatures have made use of chemical energy by the slow combination of certain chemicals with oxygen within their cells. The process is analogous to combustion, but is slower and much more delicately controlled. Sometimes use is made of energy available in the bodies of stronger species as when a remora hitches a ride on a shark, or a human being hitches an ox to a plow.

Inanimate sources of energy are sometimes used when species allow themselves to be carried or moved by wind or by water currents. In those cases, though, the inanimate source of energy must be accepted at the place and time that it happens to be and in the amount that happens to exist.