Ape-Language Studies Part II

This article was first published in Faith & Reason, 19:2, 3 (Fall 1993), pp. 221-263. Permission to print kindly granted by Christendom College Press, Christendom College, 134 Christendom Avenue, Front Royal, Virginia, 22630.


By Dennis Bonnette, Ph.D.

Critiquing the Research Data

Perhaps the most stinging defection from the ranks of those advocating an ape's grammatical competence is that of H. S. Terrace. His own research project, whose subject was a chimpanzee named Nim Chimpsky, eventually led him to question the legitimacy of initially favourable results. He then began a complete re- evaluation of his own prior data as well as that which was available from other such projects. Terrace now insists that careful analysis of all ape-language studies fails to demonstrate that apes possess grammatical competence.

Terrace suggests that in two studies using artificial language devices what the chimpanzees “learned was to produce rote sequences of the type ABCX, where A, B, and C are nonsense symbols and X is a meaningful element.”37 Thus, he argues, while the sign “apple” might have meaning for the chimpanzee, Lana,

it is doubtful that, in producing the sequence please machine give apple, Lana understood the meanings of please machine and give, let alone the relationships between these symbols that would apply in actual sentences.38

Terrace points to the importance of sign order in demonstrating simple constructions, such as subject-verb-object, and then criticizes the Gardners for failing to publish any data on sign order regarding Washoe.39

Perhaps the single most important contribution of Terrace has been his effort “to collect and to analyse a large corpus of a chimpanzee's sign combinations for regularities of sign order.”40 Moreover, he initiated:

a painstaking analysis of videotapes of Nim's and his teacher's signing. These tapes revealed much about the nature of Nim's signing that could not be seen with the naked eye. Indeed they were so rich in information that it took as much as one hour to transcribe a single minute of tape.41

These careful examinations of Nim's signing activities lead Terrace to conclude:

An ape signs mainly in response to his teachers' urgings, in order to obtain certain objects or activities. Combinations of signs are not used creatively to generate particular meanings. Instead, they are used for emphasis or in response to the teacher's unwitting demands that the ape produce as many contextually relevant signs as possible.42

Terrace points out the difficulty involved in attempting to evaluate the performance of the other signing apes:

because discourse analyses of other signing apes have yet to be published. Also, as mentioned earlier, published accounts of an ape's combinations of signs have centred around anecdotes and not around exhaustive listings of all combinations.43

Seidenberg and Petitto raise similar objections to the anecdotal foundation for some of the most significant claims made on behalf of apes:

A small number of anecdotes are repeatedly cited in discussions of the apes' linguistic skills. However, they support numerous interpretations, only the very strongest of which is the one the ape researchers prefer, i.e., that the ape was signing “creatively.” These anecdotes are so vague that they cannot carry the weight of evidence which they have been assigned. Nonetheless, two important claims—that the apes could combine signs creatively into novel sequences, and that their utterances showed evidence of syntactic structure—are based exclusively upon anecdote.44

Terrace also states that he has carefully examined films and videotape transcripts of other apes, specifically Washoe and Koko. Regarding the former, he concludes, “In short, discourse analysis makes Washoe's linguistic achievement less remarkable than it might seem at first.”45 Terrace also examined four transcripts providing data on two other signing chimpanzees, Ally and Booee. Finally, he summarizes his findings:

Nim's, Washoe's, Ally's, Booee's, and Koko's use of signs suggests a type of interaction between an ape and its trainer that has little to do with human language. In each instance the sole function of the ape's signing appears to be to request various rewards that can be obtained only by signing. Little, if any, evidence is available that an ape signs in order to exchange information with its trainer, as opposed to simply demanding some object or activity.46

Following on similar criticisms by Terrace, Seidenberg and Petitto point out the simple absence of data supporting the claims that apes show linguistic competence:

The primary data in a study of ape language must include a large corpus of utterances, a substantial number of which are analyzed in terms of the contexts in which they occurred. No corpus exists of the utterances of any ape for whom linguistic abilities are claimed.47

Terrace's Nim Chimpsky, of course, is one chimpanzee for whom linguistic ability was not claimed by his researcher. It is therefore significant that the data collected on the Nim project is, by far, the most exhaustive:

The data of Terrace et al. on Nim are more robust than those offered by other ape researchers. Although their data are limited in several respects, they are the only systematic data on any signing ape.48

If the above citation is factually correct, it means that the ape- language studies fall into two categories: (1) the Nim project, which is based upon “systematic data,” but whose researcher could find “no evidence of an ape's grammatical competence” and (2) the rest of the projects, for whose subjects various claims of linguistic competence have been made, but none of which are based upon “systematic data.”

Another weakness in the data—one which afflicts even the Nim project—is the practice of simply deleting signs which are immediately repeated:

In comparing Nim's multisign utterances and mean length of utterances (MLU) to those of children, it is important to realize that all contiguous repetitions were deleted. In this respect, Terrace et al. follow the practice established by the other ape researchers. The repetitions in ape signing constitute one of the primary differences between their behaviour and the language of deaf and hearing children, yet they have always been eliminated from analyses.49

Needless to observe, the deletion of such uselessly repeated “words” would tend to make an ape's recorded “speech” appear much more intelligible and meaningful than it actually is.

In a noteworthy understatement, Seidenberg and Petitto conclude, “There are numerous methodological problems with this research.”50

Even if all available data from ape-language studies—anecdotal and otherwise—were to be accepted at face value the legitimacy of claims about apes understanding the meanings of their signs, creating new word complexes, deceiving, lying, reasoning, etc., need not be recognized in the sense of providing proof of the possession of genuine intellectual powers on their part.

For it must be remembered that contemporary electronic computers can be programmed to simulate many of these behaviours—and, probably, in principle, all of them. Walker points out some of these capabilities:

Already there are computers which can recognise simple spoken instructions, and there are computer programs which can play the part of a psychotherapist in interchanges with real patients (Holden, 1977), so the inability of machines to conduct low-grade conversations is no longer such a strong point.51

If a computer can hold its own with real patients while feigning the role of a psychotherapist, it should surely be able to perform many of the functions of signing apes. Clearly, given appropriate sensing devices and robotics, even the most impressive, non-cued Savage-Rumbaugh experimental results could easily be simulated by computers—even by pairs of computers exhibiting the co-operative exchange of information and objects as was seen in the activities of the chimpanzees, Sherman and Austin.52 This would include the ability to “label labels,” e.g., to respond to the arbitrary pattern for banana by pressing the key meaning food.53 Such performance may seem remarkable in an ape, but it would be literal child's play to a properly programmed computer.

Again, programming a computer to “deceive” or “lie to” an interrogator is no great feat—although Woodruff and Premack apparently spent considerable time and effort creating an environment which, in effect, “programmed” chimpanzees to engage in just such unworthy conduct!54

Certainly there are, as yet, no reports about apes having learned to play chess. Yet, Walker reports:

Pocket-sized computers are now available that can play chess at a typical, if not outstanding, human level, accompanied by a rudimentary attempt at conversation about the game. . . . In the face of modern electronic technology, though, it is less obvious that it is impossible for physical devices to achieve human flexibility than it was in the seventeenth century.55

Evidently then, the electronic computer is capable of engaging in “low-grade conversations”—and this, probably in a manner which would well outstrip its nearest ape competitors.

While it must be conceded that all of the abovementioned capabilities of electronic computers presuppose the agency of very intelligent human computer programmers, yet the correlative “programming” of apes must be understood to occur as a result of deliberate human training, unintentional cuing, and unavoidable human influence upon the animals.

On the other hand, it must be recognized that the capabilities of apes equal or exceed those of computers in several significant respects. In the first place, the number of neurons in an ape's brain has been put at about 5 X 109.56 This certainly constitutes an impressive amount of almost instantaneously available “core storage.” Moreover, while it is possible to attach elaborate “sensing” devices to provide input data to a computer, nothing devised by man can match the natural abilities of the multiple external and internal senses found in higher animals, including the apes. Hence, their ability to sense and categorize a banana as food is simply part of their natural “equipment.” Finally, while extensive and complex robotic devices are now becoming an essential ingredient in various computer-controlled manufacturing processes, an ape's limbs, hands, and feet afford him a comprehensive dexterity unmatched by that of any single machine.

The point of all this is simply that none of the performances exhibited by language-trained apes exceeds in principle the capacities of electronic computers. And yet, electronic computers simply manipulate data. They experience neither intellectual nor even sentient knowledge and, in fact, do not even possess that unity of existence which is proper to a single substance. A computer is merely a pile of cleverly constructed electronic parts conjoined to form an accidental, functional unity which serves man's purpose.

It is in no way surprising, then, that man should be able to “program” apes to perform in the manner reported by researchers. For these apes have, indeed, become, as Heini Hediger so adroitly points out, artifacts—through the language and tasks which we humans have imposed upon them.57

The force of much of the above argument from analogy will be lost upon those who do not understand why we state that computers possess neither substantial existence and unity nor any sentient or intellectual knowledge. Our claims may seem especially gratuitous in an age in which various computer experts proclaim the imminent possibility of success in the search for artificial intelligence through the science of cybernetics.

Yet, it would appear to be sheer absurdity to suggest that the elementary components of complicated contemporary computers—whether considered singly or in concert—could conceivably experience anything whatsoever. For no non-living substance—whether it be an atom, a molecule, a rock, or even an electronic chip—is itself capable of sensation or intellection.

On the other hand, what answer can be given to the sceptic's seemingly absurd, but elusively difficult, query: “How can we be so certain that some form of consciousness, or at least the potency for consciousness, is not present in the apparently inanimate parts used to compose a modern computer? As any novice logician is well aware, the problems inherent in the demonstration of any negative are substantive. Hence, the challenge of proving that inanimate objects are truly non-living, non-sensing, non-thinking, etc., is difficult—the moment, of course, that one is prepared to take the issue at all seriously.

Clearly, potentialities for sensation and intellection as well as other life activities do exist—but only as faculties (operative potencies) of already living things. These powers are secondary qualities inherent in and proper to the various living species—which properties flow from their very essence and are put into act by the apprehension of the appropriate formal object. Thus, the potency for sight in an animal is a sensitive faculty of its substantial form (soul) which enables the animal to see actually when it is put into act by the presence of its proper sense object (colour). This is not the same at all as suggesting that inanimate objects as such might possess such potencies or faculties.

Despite its apparent difficulty, though, it is indeed possible to demonstrate that the universal absence of specific life activities—both in the individual and in all other things of the same essential type—shows that those life qualities are utterly outside of or missing from such a nature. Or, to put the matter affirmatively, the presence of a given form necessarily implies its formal effects, i.e., if a thing is alive, it must manifest its life activities; if sensation is a power of its nature, it must, at least at times, actually sense. That a power should exist in a given species, but never be found in act, is absolutely impossible. This fundamental truth can be shown as follows.

According to the utter certitude which is offered by the science of metaphysics, there must exist a sufficient reason why a given thing consistently exhibits certain qualities or activities, but not others. For instance, if a non-living thing, such as a rock, manifests the qualities of extension and mass, yet never exhibits any life activities, e.g., nutrition, growth, or reproduction, then either such life powers must be absent from its nature altogether, or else, if present, there must be some sufficient reason why such powers are never exhibited in act. And that reason must be either intrinsic or extrinsic to its nature. If it is extrinsic, then it would have to be accidental to the nature, and thus, caused. As St. Thomas Aquinas observes:

Everything that is in something per accidens, since it is extraneous to its nature, must be found in it by reason of some exterior cause.58

Moreover, what does not flow from the very essence of a thing cannot be found to occur universally in that thing—even if it be the universal absence of a quality or activity. For, as St. Thomas Aquinas also points out:

The power of every agent [which acts] through necessity of nature is determined to one effect, and therefore it is that every natural [agent] comes always in the same way, unless there should be an impediment.59

Hence, while an extrinsic cause might occasionally interfere with the vital activities of a living thing, such suppression of the nature's activities is relatively rare—and surely, never universal. Thus, the ability to reproduce may be suppressed by an extrinsic cause in a few individuals in a species, but most will reproduce. On the other hand, if reproduction were absent in every member of a species, e.g., rocks, then the absence of such activity must be attributed directly to the essence itself.

But if a thing is said to possess a power or potency to a certain act by its very essence, and yet, that selfsame essence is said to be responsible for its never actually exercising such a power, then such an essence becomes self-contradictory—since that essence would then be responsible both for its substance essentially being able to possess that quality and for it never being able actually to possess that same quality. The same essence would then be the reason why a thing is able to be alive or conscious and also, at the same time, the reason why that same thing is never able to be alive or conscious. This is clearly both absurd and impossible.

Moreover, Aristotle defines nature as “a source or cause of being moved and of being at rest in that to which it belongs primarily....60 But a nature which would also be the reason for a thing not moving or resting would clearly contradict itself.

From all this it follows that if a quality or activity is lacking in each and every member of a species of things, it is absent neither by accident nor as a positive effect of the essence—but simply because such quality or activity does not belong to its essence at all. Hence, non-living things have no life powers within their natures. They can gain life powers only by undergoing a substantial change, that is, by somehow becoming assimilated into the very substance of a living thing, as when a tree absorbs nutrients from the soil and then turns them into its very self.

But such is clearly not what happens when inanimate parts are artificially joined together into an accidental, functional unity such as an electronic computer. Thus, none of a computer's individual parts which are inanimate in themselves can exhibit the properties of life, sensation, or intellection. Nor can any combination of such non-living entities—even if formed into a highly complex functional unity—achieve the activities of perception or thought, since these noetic perfections transcend utterly the individual natures, and thus, the natural limitations, of its components.

Since it is an artificial composite of many substances, a computer constitutes merely an accidental unity. As such, no accidental perfection can exist in it which is not grounded in the natures of its constituent elements. It is a perennial temptation to engage in the metaphysical slight of hand of suggesting that somehow the whole might be greater than the sum of its parts, that the total collectivity can exhibit qualities of existence found in none of its elements. In this strange way, like Pinocchio, the computer is averred to take on suddenly all the properties of a living substance—to sense and to think.

But such is the stuff of fantasy. It is to commit the fallacy of composition—to attribute to the whole qualities found in none of its parts. It is like suggesting that an infinite multitude of idiots could somehow—if only properly arranged—constitute a single genius. The fundamental obstacle to all such speculation is the principle of sufficient reason. For the non-living, as such, offers no existential foundation for the properties of life. And merely accidental rearrangements of essentially non-living components provide no sufficient reason for the positing of the essentially higher activities found in living things—unless there takes place the sort of substantial change described above. And such substantial changes are found solely in the presently constituted natural order of things, i.e., by assimilation or generation.

Since the hylemorphist philosopher understands that the substantial unity of things above the atomic level depends upon some unifying principle, i.e., the substantial form, he knows that only natural unities possessing appropriate cognitive faculties of sensation or intellection can actually know anything. Thus a “sensing device” such as a television set running in an empty room actually senses nothing. It cannot see its own picture or hear its own sound. No genuine perception can occur until, say, a dog stumbles into the room and glances at the set in operation. The dog can see and hear the set precisely because the dog is a natural living substantial unity whose primary matter is specified and unified by a substantial form (its soul) which possesses the sense faculties of sight and hearing. Absent the sensitive soul, the most complex “sensing device” knows nothing of the sense data it records. Absent the intellectual soul, a “thinking” machine understands nothing of the intelligible data it manipulates nor even is it aware of its own existence. A computer could well be programmed to pronounce, “Cogito ergo sum,” and yet remain completely unaware of its own existence or anything else. To top

Godel's Theorem

The inherent limitations of any electronic computer were unintentionally underlined by the German mathematician Kurt Godel in 1930 when he proposed his famed incompleteness theorem to the Vienna Academy of Sciences. Expressed in disarmingly simply terms, the theorem states “that even in the elementary parts of arithmetic there are propositions which cannot be proved or disproved in that system.”61 Godel himself initially vastly underestimated the profound implications of his theorem. Among these were (1) that it struck “a fatal blow to Hilbert's great program to formalize the whole of mathematics...”62 and (2) that it “cuts the ground under the efforts that view machines... as adequate models of the mind.”63

The distinguished theologian and physicist Stanley L. Jaki spells out the impact of the incompleteness theorem on the question of computer consciousness:

Actually, when a machine is requested to prove that “a specific formula is unprovable in a particular system,” one expects the machine to be self-conscious, or in other words, that it knows that it knows it, and that it knows that it knows it that it knows it, and so forth ad infinitum.... A machine would always need an extra part to reflect on its own performance, and therein lies the Achilles heel of the reasoning according to which a machine with a sufficiently high degree of complexity will become conscious. Regardless of how one defines consciousness, such a machine, as long as it is a machine in the accepted sense of the word, will not and cannot be fully self-conscious. It will not be able to reflect on its last sector of consciousness.64

Despite the logical adroitness of this analysis, we must, of course, remember that in truth and in fact machines possess no psychic faculties at all. They actually have neither even the most immediate level of reflection nor any form of consciousness whatever.

What Godel's theorem simply implies is that men are not machines—that computers (because they have not a spiritual intellect) are unable to know the truth of their own “judgments” since they lack the capacity for self-reflective consciousness.

This analysis of computer deficiency based upon the incompleteness theorem is offered simply to demonstrate that, although computers may be able to simulate the abilities of language-trained apes, their computations, nonetheless, remain essentially inferior to human cognitive abilities. In truth, neither apes nor computers are capable of genuinely self-reflective acts of intellection since such acts are possible for creatures with spiritual intellects alone, e.g., man.65

Nonetheless, the fact that electronic computers—having neither sensation nor intellection nor even life itself—could, in principle, be designed and programmed so as to imitate, or even exceed, the skills of language-trained apes is sufficient evidence that ape-language studies pose no threat to man's uniqueness as a species. Nor do the studies cast in any doubt man's uniquely spiritual nature—as distinguished from the rest of the animal kingdom.

One striking bit of information drawn from the history of ape- language studies has been saved until this point in our study in order to underscore the radical difference between man and lesser primates. It demonstrates, as Paul Bouissac points out, that the animal's perspective on what is going on may differ radically from our own. Now no language-trained ape possesses a greater reputation for linguistic expertise and presumed civility than the female chimpanzee, Washoe. It is therefore rather appalling to learn of the following incident reported by Bouissac:

There are indeed indications that accidents are not infrequent, although they have never been publicized; the recent attack of the celebrated “Washoe” on Karl Pribram, in which the eminent psychologist lost a finger (personal communication, June 13, 1980) was undoubtedly triggered by a situation that was not perceived in the same manner by the chimpanzee and her human keepers and mentors.66

In pointing to the divergence of perspective between man and ape, Bouissac may well understate the problem. Washoe would have been about 15 years old at the time of the attack. Needless to say, humans of that age have virtually never been recorded as even attempting to bite their teachers—and this would seem especially true of outstanding students!

This clear-cut evidence that animals—even apes—simply do not perceive the communicative context in the same way that man does demonstrates the degree to which the anthropomorphic fallacy has overtaken many researchers—despite their claims of caution in this regard. To top

A Positive Demonstration

While much of the preceding discussion pertinent to man's uniqueness as a species has focused upon signs of his spiritual nature and, to an even greater degree, upon the failure of lower animals to demonstrate any intellectual ability, philosopher and theologian Austin M. Woodbury, S.M., approaches the question with a fresh and more decisive perspective.67 He points out that the effort to explain all animal behaviour in terms of sensation alone could never be completed and might produce no more than a probable conclusion because of the complexity of the task. One need only consider the endless anecdotal data to be examined.68 To avoid the logical weakness of this negative approach, Woodbury proposes an appropriate remedy by seeking direct and positive proof that brutes are lacking in the necessary effects or signs of intelligence.69

For, he argues, the necessary effects of intellect are four: speech, progress, knowledge of relations, and knowledge of immaterial objects. Since each of these is a necessary effect, “if it be shown that even one of these signs of intellect is lacking to 'brutes', then it is positively proved that 'brutes' are devoid of intellect.”70 In fact, Woodbury argues that brute animals are in default in all four areas.

While the most significant ape-language experiments were conducted after Woodbury wrote his Psychology, nonetheless his insistence on the absence of true speech among brute animals remains correct as we have seen above. He points out that animals possess the organs of voice (or, we might note, the hands to make signs), the appropriate sensible images, and the inclination to manifest their psychic states—but they do not manifest true speech since they lack intellect.71

What Woodbury seems to be saying is that, if brute animals actually possessed intellect, they would have long ago developed their own forms of communication expressed in arbitrary or conventional signs. Their failure to do so is manifest evidence of the absence of intellect. On the contrary, since all men do possess intellect, all men develop speech.72 While he does not, of course, make reference here to the signing apes, it is clear that their behaviour is to be explained by imitation and the association of images. While man may impose signing upon such animals artificially, their failure to have developed language on their own and in their natural habitat demonstrates lack of true speech. That animals possess natural signs is conceded, but irrelevant.

Neither do animals present evidence of genuine progress. Woodbury points out that “from intellect by natural necessity follows progress in works, knowledges and sciences, arts and virtue.”73 While he grants that animals do learn from experience, imitation, and training, yet, because they lack the capacity for intellectual self-reflection, they are unable to correct themselves—an ability absolutely essential to true progress.

Even in the most “primitive” societies, true men make progress as individuals. For children learn language, arts, complex tribal organization, complex legal systems, and religious rites.74 Woodbury notes, “Moreover, the lowest of such peoples can be raised by education to very high culture.”75

Woodbury points out that the appetite to make deliberate progress is inherent in a being endowed with intellect and will. For as the intellect naturally seeks the universal truth and the will seeks the infinite good, no finite truth or good offers complete satisfaction. Thus man, both as a species and as an individual, seeks continually to correct and perfect himself. While apes are ever content to satisfy the same sensitive urges, men erect the ever-advancing technology and culture which mark the progress of civilization. The failure of animals to make anything but accidental improvements—except when the intellect of man imposes itself upon them through training—proves the utter absence of intellect within their natures.

Commenting on his third sign that intellect is lacking in animals, Woodbury observes that brute animals lack a formal knowledge of relations. They fail to understand the means-end relationship in its formal significance. And, while men grasp the formal character of the cause-effect relationship in terms of being itself, animals are limited merely to perceiving and associating a succession of events.76

Woodbury distinguishes between possessing a universal understanding of the ontological nature of means in relation to ends as opposed to possessing a merely sensitive knowledge of related singular things. Lower animals reveal their lack of such understanding whenever conditions change so as to make the ordinarily attained end of their instinctive activity unobtainable. For they then show a lack of versatility in devising a substitute means to that end. Also, they will continue to repeat the now utterly futile action which instinct presses upon them. Woodbury offers this example:

Thus apes, accustomed to perch themselves on a box to reach fruit, if the box be absent, place on the ground beneath the fruit a sheet of paper and perch themselves thereupon.77

This same example reveals how lower animals “show no knowledge of distinction between causality and succession....”78 Clearly, had they any understanding of causality, the apes would not conceive a “sheet of paper” as causally capable of lifting them significantly toward the fruit.

The fourth and final sign that intellect is clearly lacking in animals pertains to knowledge of immaterial things. Woodbury points out that our intellectual nature impels us to a knowledge of science, the exercise of free choice, the living of a moral life, the exercise of religion, etc.79 Such abstract and evidently supra-temporal objects are so clearly absent in the life of apes and other animals as to need no further comment.

Thus we see that brute animals, including apes, are clearly lacking in all four of the necessary formal effects of intellect, that is, speech, progress, knowledge of relations, and knowledge of immaterial objects. From this it follows with apodictic certitude that lower animals must lack the intellective faculties. To top

Image and Concept

Perhaps the most important distinction to be kept in mind when attempting to understand animal behaviour is that offered by Woodbury when he discusses the intellectual knowing of universal concepts as opposed to the knowledge had through a common image or common scheme—since it is very tempting to identify the two, as materialists are so prone to do. He presents this definition of the common image:


Since the entire sensitive life of apes and lower animals (including the phenomena associated with signing behaviour) is rooted in the association of images, and since common images are so frequently confused with universal concepts, one can readily understand the errors of so many modern animal researchers. They suffer the same confusion as the 18th century sensist philosopher, David Hume, who conceived images as sharply focused mental impressions and ideas as simply pale and derivative images.81 Neither he nor the modern positivistic animal researchers understand the essential distinction between the image and the concept.

And yet, it is precisely in this distinction that the radical difference between the material and spiritual orders becomes manifest. For, being rooted in the individuating, quantifying character of matter, the image is always of the singular. It is always particular, sensible, concrete and, in a word, imaginable—as one can easily imagine a single horse or even a group of horses. On the contrary, the concept—because it involves no intrinsic dependence upon matter at all—is universal in nature. It entails no sensible qualities whatever, can have varying degrees of extension when predicated, and is entirely unimaginable. No one can imagine horseness. No single image of a horse or group of horses would fit equally all horses—even though the common image of “a horse” would enable a fox to recognize sentiently the sensible similarities of all horses. In fact, this “common image” is more useful for the instinctive life of animals—for it suffices the cat to know the common image of a mouse in order that its estimative sense may sensibly recognize it as an object to be pounced upon and eaten. The intellectual understanding of the internal essence of a mouse may well be suited to the interest of the professional biologist—but it is hardly necessary or even very helpful to the famished feline predator.82

In order to see more fully the significance of the distinction between mere recognition of a common image and true intellectual apprehension of an intelligible essence, let us consider the following example: Imagine a dog, an uneducated aborigine, and a civilized man—all observing a train pulling into a station at the same time over successive days. All three would possess a common image of the train which would permit sensible recognition of the likeness of the singular things involved, i.e., the sequentially observed trains. (Whether it is, in fact, the exact same engine, cars, and caboose is irrelevant—since similar sets of singular things could be known through a common image.)

Yet, the sensible similarities are all that the dog would perceive. In addition, the civilized man would understand the essence of the train. He would grasp the intelligibility of the inner workings of the causal forces of fire on water producing steam whose expansion drives pistons to move wheels which pull the whole vehicle, cargo and passengers as well, forward in space through the passage of time.

Well enough. But what of the uneducated aborigine? What differentiates him from the dog is that, even though he may not initially know the intrinsic nature of the train, his intellect is at once searching for an answer to the why of the entire prodigy. He may make what, to us, would be amazing errors in this regard—as did the natives of Borneo who are reported to have attempted to give animal feed to cargo planes which landed there during World War II. But search the causes in being of the inner structure of the train, he certainly would! And, most importantly, with but a little explanation the aborigine would quickly come to the same basic understanding of the train as the rest of us—while the dog still would bark uselessly at its noise.

So too, when man and mouse perceive the same mousetrap what is perceived is quite different. The mouse sees the cheese; we see a potentially death-dealing trap. Small wonder, then, the divergence of perspective between psychologist Pribram and chimpanzee Washoe concerning the proper role of Pribram's finger in the context of their “communication”! For at every level of communication it must be remembered that the perception of animals is purely sensory while that of man is both sensory and intellectual. Thus the mouse sees the cheese in a strictly sensory manner and as the object of its purely sensitive appetite. On the other hand, a man sees both sensitively and in the analogous meaning of intellectual “sight.” Thus the deadliness of the trap is evident to man alone. The mouse—from a past close call—may react in fear before the trap because it associates an image of the trap with an image of earlier (non-fatal) pain. Yet, only man knows why the mouse should be afraid.

By now it should be quite clear that the available animal studies are entirely consistent with the above explanation. Moreover, this explanation is the only one which fits the facts—since animals, as Woodbury has shown, reveal that they lack the intellectual faculties which we possess. To top


In the course of our examination of the question under investigation we have distinguished man from lower animals in two ways: First, we have demonstrated that the presently available natural scientific evidence regarding lower animal behaviour, including the recent ape-language studies, constitutes no legitimate challenge to the essential superiority of the human intellect. Second, we have presented briefly Woodbury's positive demonstrations for the non-existence of intellect in lower animals. We have also noted many of the unique capabilities and accomplishments of man—both individually and collectively considered—which bespeak his possession of intellectual faculties which utterly transcend the world of brutes.


  1. Summa Theologiae, I, q. 75, aa. 1-7. See also Etienne Gilson, The Elements of Christian Philosophy (New York and Toronto: [Mentor-Omega], The New American Library, 1960), pp. 222-240; Frederick Copleston, S.J., A History of Philosophy, Vol. 2, Mediaeval Philosophy, Part II (Garden City, NY: Image Books, 1962), pp. 102-107; Brother Benignus, F.S.C., Nature, Knowledge, and God (Milwaukee: The Bruce Publishing Company, 1947), pp. 188-210.
  2. November 1979, Vol. 13, No. 6.
  3. H. S. Terrace, “How Nim Chimpsky Changed My Mind,” Psychology Today, November 1979, Vol. 13, No. 6, p. 67.
  4. Suzanne Chevalier-Skolnikoff, “The Clever Hans Phenomenon, Cuing, and Ape Signing: A Piagetian Analysis of Methods for Instructing Animals” in The Clever Hans Phenomenon: Communication with Horses, Whales, Apes, and People, Thomas A. Sebeok and Robert Rosenthal, eds. (New York: New York Academy of Sciences, 1981), pp. 89-90.
  5. Ibid., p. 83.
  6. Thomas A. Sebeok and Jean Umiker-Sebeok, “Performing Animals: Secrets of the Trade” in Psychology Today, November 1979, p. 91.
  7. Ibid., p. 81.
  8. Stephen Walker, Animal Thought (London-Boston-Melbourne- Henley: Routledge & Kegan Paul, 1983), pp. 373-374.
  9. Duane M. Rumbaugh, “Who Feeds Clever Hans?” in The Clever Hans Phenomenon, p. 33. See also ibid., pp. 26-34 and E. Sue Savage- Rumbaugh, “Can Apes Use Symbols to Represent Their World?” in The Clever Hans Phenomenon, pp. 35-59.
  10. Sebeok and Umiker-Sebeok, “Performing Animals” in Psychology Today, p. 91.
  11. Walker, Animal Thought, p. 373.
  12. Ibid., pp. 365-367.
  13. Ibid., p. 369.
  14. Ibid., pp. 369-370.
  15. Ibid., pp. 370-371.
  16. Ibid., pp. 377-378.
  17. Ibid., p. 378.
  18. Ibid., p. 379. Please note that human beings are “educated,” not “trained.”
  19. Ibid., p. 387.
  20. Ibid., p. 357.
  21. Heini K. P. Hediger, “The Clever Hans Phenomenon from an Animal Psychologist's Point of View” in The Clever Hans Phenomenon, p. 5.
  22. Aristotle, On Interpretation, 1 (16a3-8).
  23. Hediger in The Clever Hans Phenomenon, p. 9.
  24. Ibid.
  25. Ibid., p. 13.
  26. Ibid.
  27. Ibid., p. 14.
  28. Ibid., p. 16.
  29. Sebeok and Umiker-Sebeok, “Performing Animals” in Psychology Today, p. 91.
  30. Walker, Animal Thought, pp. 352-381.
  31. Hediger in The Clever Hans Phenomenon, p. 14. In his History of Animals, VIII, 1, (589a3-589a9), Aristotle makes much the same point: “The life of animals, then, may be divided into two acts—procreation and feeding; for on these two acts all their interests and life concentrate. Their food depends chiefly on the substance of which they are severally constituted; for the source of their growth in all cases will be this substance. And whatsoever is in conformity with nature is pleasant, and all animals pursue pleasure in keeping with their nature.”
  32. Chevalier-Skolnikoff in The Clever Hans Phenomenon, p. 83.
  33. Ibid., p. 84.
  34. Walker, Animal Thought, p. 374.
  35. Chevalier-Skolnikoff in The Clever Hans Phenomenon, pp. 89- 90.
  36. Ibid., p. 86.
  37. H. S. Terrace, “A Report to an Academy, 1980” in The Clever Hans Phenomenon, p. 95.
  38. Ibid.
  39. Ibid., p. 96.
  40. Ibid., p. 97.
  41. Ibid., p. 103.
  42. Ibid., pp. 107-108.
  43. Ibid., p. 108.
  44. Mark S. Seidenberg and Laura A. Petitto, “Ape Signing: Problems of Method and Interpretation” in The Clever Hans Phenomenon, p. 116.
  45. Terrace in The Clever Hans Phenomenon, p. 109.
  46. Ibid., pp. 109-110.
  47. Seidenberg and Petitto in The Clever Hans Phenomenon, p. 116.
  48. Ibid., pp. 121-122.
  49. Ibid., p. 123.
  50. Ibid., p. 127.
  51. Walker, Animal Thought, p. 9.
  52. Ibid., pp. 364-370, 373.
  53. Ibid., pp. 369-370.
  54. Ibid., pp. 370-371.
  55. Ibid., pp. 10-11.
  56. According to the eminent physicist-theologian Stanley L. Jaki, the number of potential memory units in the brain is phenomenal. See his Brain, Mind and Computers (New York: Herder and Herder, 1969). He writes, “After all, the latitude between 1027, the estimated number of molecules in the brain, and 1010, the estimated number of neurons, is enormous enough to accommodate any guess, however bold, fanciful, or arbitrary.” (page 110) Since on page 115, he tells us that “the human brain... [has] ...twice as many neurons as the number of neurons in the brain of apes,” we conclude that the number of neurons in the brain of apes must be 5 X 109.
  57. Hediger in The Clever Hans Phenomenon, p. 5.
  58. Quia omne quod inest alicui per accidens, cum sit extraneum a natura eius, oportet quod conveniat ei ex aliqua exteriori causa.De Potentia Dei, q. 10, a. 4, c. Quaestiones Disputatae, 10th Edition (Taurini-Romae: Marietti, 1965).
  59. Omnis enim agentis per necessitatem naturae, virtus determinatur ad unum effectum; et inde est quod omnia naturalia semper eveniant eodem modo, nisi sit impedimentum.” Summa Contra Gentiles, III, 23, ed. (Leonine, Rome, 1888).
  60. Aristotle, Physics II, 1, 192b22-23, The Basic Works of Aristotle, ed. Richard McKeon (New York: Random House, 1941), p. 236.
  61. Jaki, Brain, Mind and Computers, p. 214.
  62. Ibid., p. 215.
  63. Ibid., p. 216.
  64. Ibid., pp. 220-221.
  65. Unlike computers, apes, of course, are alive and possess sensitive souls capable of sense consciousness—but not intellection.
  66. Paul Bouissac, “Behavior in Context: In What Sense is a Circus Animal Performing?” in The Clever Hans Phenomenon, p. 24.
  67. A. M. Woodbury, Natural Philosophy, Treatise Three, Psychology, III, Ch. 40, Art. 2 (Sydney: Aquinas Academy, 1951), pp. 432-465.
  68. Ibid., p. 437.
  69. Ibid., p. 438.
  70. Ibid.
  71. Ibid., p. 441.
  72. It is noteworthy that even a chimpanzee brought up in a human family learns no speech at all whereas a human child does so easily and quickly. While it is conceded that chimpanzees and other apes lack the vocal dexterity of man, yet it must be noted that they do possess sufficient vocal equipment to enable them to make limited attempts at speech—just as would any human suffering from a severe speech defect. Yet, apes attempt nothing of the sort.
  73. Ibid., p. 443.
  74. Ibid., p. 444.
  75. Ibid.
  76. Ibid., p. 445.
  77. Ibid., p. 447.
  78. Ibid., p. 448.
  79. Ibid.
  80. Ibid., p. 433.
  81. David Hume, A Treatise of Human Nature, Vol. I, Book I, Sect. I (London: J. M. Dent & Sons, Ltd., 1956), pp. 11-16.
  82. Woodbury, Natural Philosophy, p. 434.

See also "Ape-Language Studies" - Part I

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