I will first try to show, by taking the best stories I can find of animal sagacity, that the mental process involved may as a rule be perfectly accounted for by mere contiguous association, based on experience. Mr. Darwin, in his 'Descent of Man,' instances the Arctic dogs, described by Dr. Hayes, who scatter, when drawing a sledge, as soon as the ice begins to crack. This might be called by some an exercise of reason. The test would be, Would the most intelligent Eskimo dogs that ever lived act so when placed upon ice for the first time together? A band of men from the tropics might do so easily. Recognizing cracking to be a sign of breaking, and seizing immediately the partial character that the point of rupture is the point of greatest strain, and that the massing of weight at a given point concentrates there the strain, a Hindoo might quickly infer that scattering would stop the cracking, and, by crying out to his comrades to disperse, save the party from immersion. But in the dog's case we need only suppose that they have individually experienced wet skins after cracking, that they have often noticed cracking to begin when they were huddled together, and that they have observed it to cease when they scattered. Naturally, therefore, the sound would redintegrate all these former experiences, including that of scattering, which latter they would promptly renew. It would be a case of immediate suggestion or of that 'Logic of Recepts' as Mr. Romanes calls it, of which we spoke above on p. 327.
A friend of the writer gave as a proof of the almost human intelligence of his dog that he took him one day down to his boat on the shore, but found the boat full of dirt and water. He remembered that the sponge was up at the house, a third of a mile distant; but, disliking to go back himself, he made various gestures of wiping out the boat and so forth, saying to his terrier, "Sponge, sponge; go fetch the sponge." But he had little expectation of a result, since the dog had never received the slightest training with the boat or the sponge. Nevertheless, off he trotted to the house, and, to his owner's great surprise and admiration, brought the sponge in his jaws. Sagacious as this was, it required nothing but ordinary contiguous association of ideas. The terrier was only exceptional in the minuteness of his spontaneous observation. Most terriers would have taken no interest in the boat-cleaning operation, nor noticed what the sponge was for. This terrier, in having picked those details out of the crude mass of his boat-experience distinctly enough to be reminded of them, was truly enough ahead of his peers on the line which leads to human reason. But his act was not yet an act of reasoning proper. It might fairly have been called so if, unable to find the sponge at the house, he had brought back a dipper or a mop instead. Such a substitution would have shown that, embedded in the very different appearances of these articles, he had been able to discriminate the identical partial attribute of capacity to take up water, and had reflected, "For the present purpose they are identical." This, which the dog did not do, any man but the very stupidest could not fail to do.
If the reader will take the trouble to analyze the best dog and elephant stories he knows, he will find that, in most cases, this simple contiguous calling up of one whole by another is quite sufficient to explain the phenomena. Sometimes, it is true, we have to suppose the recognition of a property or character as such, but it is then always a character which the peculiar practical interests of the animal may have singled out. A dog, noticing his master's hat on its peg, may possibly infer that he has not gone out. Intelligent dogs recognize by the tone of the master's voice whether the latter is angry or not. A dog will perceive whether you have kicked him by accident or by design, and behave accordingly. The character inferred by him, the particular mental state in you, however it be represented in his mind—it is represented probably by a 'recept' (p. 327) or set of practical tendencies, rather than by a definite concept or idea—is still a partial character extracted from the totality of your phenomenal being, and is his reason for crouching and skulking, or playing with you. Dogs, moreover, seem to have the feeling of the value of their master's personal property, or at least a particular interest in objects which their master uses. A dog left with his master's coat will defend it, though never taught to do so. I know of a dog accustomed to swim after sticks in the water, but who always refused to dive for stones. Nevertheless, when a fish-basket, which he had never been trained to carry, but merely knew as his master's, fell over, he immediately dived after it and brought it up. Dogs thus discern, at any rate so far as to be able to act, this partial character of being valuable, which lies hidden in certain things.[335] Stories are told of dogs carrying coppers to pastry-cooks to get buns, and it is said that a certain dog, if he gave two coppers, would never leave without two buns. This was probably mere contiguous association, but it is possible that the animal noticed the character of duality, and identified it as the same in the coin and the cake. If so, it is the maximum of canine abstract thinking. Another story told to the writer is this: a dog was sent to a lumber-camp to fetch a wedge, with which he was known to be acquainted. After half an hour, not returning, he was sought and found biting and tugging at the handle of an axe which was driven deeply into a stump. The wedge could not be found. The teller of the story thought that the dog must have had a clear perception of the common character of serving to split which was involved in both the instruments, and, from their identity in this respect, inferred their identity for the purposes required.
It cannot be denied that this interpretation is a possible one, but it seems to me far to transcend the limits of ordinary canine abstraction. The property in question was not one which had direct personal interest for the dog, such as that of belonging to his master is in the case of the coat or the basket. If the dog in the sponge story had returned to the boat with a dipper it would have been no more remarkable. It seems more probable, therefore, that this wood-cutter's dog had also been accustomed to carry the axe, and now, excited by the vain hunt for the wedge, had discharged his carrying powers upon the former instrument in a sort of confusion—just as a man may pick up a sieve to carry water in, in the excitement of putting out a fire.[336]
Thus, then, the characters extracted by animals are very few, and always related to their immediate interests or emotions. That dissociation by varying concomitants, which in man is based so largely on association by similarity, hardly seems to take place at all in the mind of brutes. One total thought suggests to them another total thought, and they find themselves acting with propriety, they know not why. The great, the fundamental, defect of their minds seems to be the inability of their groups of ideas to break across in unaccustomed places. They are enslaved to routine, to cut-and-dried thinking; and if the most prosaic of human beings could be transported into his dog's mind, he would be appalled at the utter absence of fancy which reigns there.[337] Thoughts will not be found to call up their similars, but only their habitual successors. Sunsets will not suggest heroes' deaths, but supper-time. This is why man is the only metaphysical animal. To wonder why the universe should be as it is presupposes the notion of its being different, and a brute, which never reduces the actual to fluidity by breaking up its literal sequences in his imagination, can never form such a notion. He takes the world simply for granted, and never wonders at it at all.
Professor Strümpell quotes a dog-story which is probably a type of many others. The feat performed looks like abstract reasoning; but an acquaintance with all the circumstances shows it to have been a random trick learned by habit. The story is as follows:
"I have two dogs, a small, long-legged pet dog and a rather large watch-dog. Immediately beyond the house-court is the garden, into which one enters through a low lattice-gate which is closed by a latch on the yard-side. This latch is opened by lifting it. Besides this, moreover, the gate is fastened on the garden-side by a string nailed to the gate-post. Here, as often as one wished, could the following sight be observed. If the little dog was shut in the garden and he wished to get out, he placed himself before the gate and barked. Immediately the large dog in the court would hasten to him and raise the latch with his nose while the little dog on the garden-side leaped up and, catching the string in his teeth, bit it through; whereupon the big one wedged his snout between the gate and the post, pushed the gate open, and the little dog slipped through. Certainly reasoning seems here to prevail. In face of it, however, and although the dogs arrived of themselves, and without human aid, at their solution of the gate question, I am able to point out that the complete action was pieced together out of accidental experiences which the dogs followed, I might say, unconsciously. While the large dog was young, he was allowed, like the little one, to go into the garden, and therefore the gate was usually not latched, but simply closed. Now if he saw anyone go in, he would follow by thrusting his snout between gate and post, and so pushing the gate open. When he was grown I forbade his being taken in, and had the gate kept latched. But he naturally still tried to follow when anyone entered and tried in the old fashion to open it, which he could no longer do. Now it fell out that once, while making the attempt, he raised his nose higher than usual and hit the latch from below so as to lift it off its hook, and the gate unclosed. From thenceforth he made the same movement of the head when trying to open it, and, of course, with the same result. He now knew how to open the gate when it was latched.
"The little dog had been the large one's teacher in many things, especially in the chasing of cats and the catching of mice and moles; so when the little one was heard barking eagerly, the other always hastened to him. If the barking came from the garden, he opened the gate to get inside. But meanwhile the little dog, who wanted to get out the moment the gate opened, slipped out between the big one's legs, and so the appearance of his having come with the intention of letting him out arose. And that it was simply an appearance transpired from the fact that when the little dog did not succeed at once in getting out, the large one ran in and nosed about the garden, plainly showing that he had expected to find something there. In order to stop this opening of the gate I fastened a string on the garden-side which, tightly drawn, held the gate firm against the post, so that if the yard dog raised the latch and let go, it would every time fall back on to the hook. And this device was successful for quite a time, until it happened one day that on my return from a walk upon which the little dog had accompanied me I crossed the garden, and in passing through the gate the dog remained behind, and refused to come to my whistle. As it was beginning to rain, and I knew how he disliked to get wet, I closed the gate in order to punish him in this manner. But I had hardly readied the house ere he was before the gate, whining and crying most piteously, for the rain was falling faster and faster. The big dog, to whom the rain was a matter of perfect indifference, was instantly on hand and tried his utmost to open the gate, but naturally without success. Almost in despair the little dog bit at the gate, at the same time springing into the air in the attempt to jump over it, when he chanced to catch the string in his teeth; it broke, and the gate flew open. Now he knew the secret and thenceforth bit the string whenever he wished to get out, so that I was obliged to change it.
"That the big dog in raising the latch did not in the least know that the latch closed the gate, that the raising of the same opened it, but that he merely repeated the automatic blow with his snout which had once had such happy consequences, transpires from the following: the gate leading to the barn is fastened with a latch precisely like the one on the garden-gate, only placed a little higher, still easily within the dog's reach. Here, too, occasionally the little dog is confined, and when he barks the big one makes every possible effort to open the gate, but it has never occurred to him to push the latch up. The brute cannot draw conclusions, that is, he cannot think."[338]
Other classical differentiæ of man besides that of being the only reasoning animal, also seem consequences of his unrivalled powers of similar association. He has, e.g., been called 'the laughing animal.' But humor has often been defined as the recognition of identities in things different. When the man in Coriolanus says of that hero that "there is no more mercy in him than there is milk in a male tiger," both the invention of the phrase and its enjoyment by the hearer depend on a peculiarly perplexing power to associate ideas by similarity.
Man is known again as 'the talking animal'; and language is assuredly a capital distinction between man and brute. But it may readily be shown how this distinction merely flows from those we have pointed out, easy dissociation of a representation into its ingredients, and association by similarity.
Language is a system of signs, different from the things signified, but able to suggest them.
No doubt brutes have a number of such signs. When a dog yelps in front of a door, and his master, understanding his desire, opens it, the dog may, after a certain number of repetitions, get to repeat in cold blood a yelp which was at first the involuntary interjectional expression of strong emotion. The same dog may be taught to 'beg' for food, and afterwards come to do so deliberately when hungry. The dog also learns to understand the signs of men, and the word 'rat' uttered to a terrier suggests exciting thoughts of the rat-hunt. If the dog had the varied impulse to vocal utterance which some other animals have, he would probably repeat the word 'rat' whenever he spontaneously happened to think of a rat-hunt—he no doubt does have it as an auditory image, just as a parrot calls out different words spontaneously from its repertory, and having learned the name of a given dog will utter it on the sight of a different dog. In each of these separate cases the particular sign may be consciously noticed by the animal, as distinct from the particular thing signified, and will thus, so far as it goes, be a true manifestation of language. But when we come to man we find a great difference. He has a deliberate intention to apply a sign to everything. The linguistic impulse is with him generalized and systematic. For things hitherto unnoticed or unfelt, he desires a sign before he has one. Even though the dog should possess his 'yelp' for this thing, his 'beg' for that, and his auditory image 'rat' for a third thing, the matter with him rests there. If a fourth thing interests him for which no sign happens already to have been learned, he remains tranquilly without it and goes no further. But the man postulates it, its absence irritates him, and he ends by inventing it. This general purpose constitutes, I take it, the peculiarity of human speech, and explains its prodigious development.
How, then, does the general purpose arise? It arises as soon as the notion of a sign as such, apart from any particular import, is born; and this notion is born by dissociation from the outstanding portions of a number of concrete cases of signification. The 'yelp,' the 'beg,' the 'rat,' differ as to their several imports and natures. They agree only in so far as they have the same use—to be signs, to stand for something more important than themselves. The dog whom this similarity could strike would have grasped the sign per se as such, and would probably thereupon become a general sign-maker, or speaker in the human sense. But how can the similarity strike him? Not without the juxtaposition of the similars (in virtue of the law we have laid down (Vol. I. p. 506), that in order to be segregated an experience must be repeated with varying concomitants)—not unless the 'yelp' of the dog at the moment it occurs recalls to him his 'beg,' by the delicate bond of their subtle similarity of use—not till then can this thought flash through his mind: "Why, yelp and beg, in spite of all their unlikeness, are yet alike in this: that they are actions, signs, which lead to important boons. Other boons, any boons, may then be got by other signs!" This reflection made, the gulf is passed. Animals probably never make it, because the bond of similarity is not delicate enough. Each sign is drowned in its import, and never awakens other signs and other imports in juxtaposition. The rat-hunt idea is too absorbingly interesting in itself to be interrupted by anything so uncontiguous to it as the idea of the 'beg for food,' or of 'the door-open yelp,' nor in their turn do these awaken the rat-hunt idea.
In the human child, however, these ruptures of contiguous association are very soon made; far off cases of sign-using arise when we make a sign now; and soon language is launched. The child in each case makes the discovery for himself. No one can help him except by furnishing him with the conditions. But as he is constituted, the conditions will sooner or later shoot together into the result.[339]
The exceedingly interesting account which Dr. Howe gives of the education of his various blind-deaf mutes illustrates this point admirably. He began to teach Laura Bridgman by gumming raised letters on various familiar articles. The child was taught by mere contiguity to pick out a certain number of particular articles when made to feel the letters. But this was merely a collection of particular signs, out of the mass of which the general purpose of signification had not yet been extracted by the child's mind. Dr. Howe compares his situation at this moment to that of one lowering a line to the bottom of the deep sea in which Laura's soul lay, and waiting until she should spontaneously take hold of it and be raised into the light. The moment came, 'accompanied by a radiant flash of intelligence and glow of joy'; she seemed suddenly to become aware of the general purpose imbedded in the different details of all these signs, and from that moment her education went on with extreme rapidity.
Another of the great capacities in which man has been said to differ fundamentally from the animal is that of possessing self-consciousness or reflective knowledge of himself as a thinker. But this capacity also flows from our criterion, for (without going into the matter very deeply) we may say that the brute never reflects on himself as a thinker, because he has never clearly dissociated, in the full concrete act of thought, the element of the thing thought of and the operation by which he thinks it. They remain always fused, conglomerated—just as the interjectional vocal sign of the brute almost invariably merges in his mind with the thing signified, and is not independently attended to in se.[340]
Now, the dissociation of these two elements probably occurs first in the child's mind on the occasion of some error or false expectation which would make him experience the shock of difference between merely imagining a thing and getting it. The thought experienced once with the concomitant reality, and then without it or with opposite concomitants, reminds the child of other cases in which the same provoking phenomenon occurred. Thus the general ingredient of error may be dissociated and noticed per se, and from the notion of his error or wrong thought to that of his thought in general the transition is easy. The brute, no doubt, has plenty of instances of error and disappointment in his life, but the similar shock is in him most likely always swallowed up in the accidents of the actual case. An expectation disappointed may breed dubiety as to the realization of that particular thing when the dog next expects it. But that disappointment, that dubiety, while they are present in the mind, will not call up other cases, in which the material details were different, but this feature of possible error was the same. The brute will, therefore, stop short of dissociating the general notion of error per se, and a fortiori will never attain the conception of Thought itself as such.
We may then, we think, consider it proven that the most elementary single difference between the human mind and that of brutes lies in this deficiency on the brute's part to associate ideas by similarity—characters, the abstraction of which depends on this sort of association, must in the brute always remain drowned, swamped in the total phenomenon which they help constitute, and never used to reason from. If a character stands out alone, it is always some obvious sensible quality like a sound or a smell which is instinctively exciting and lies in the line of the animal's propensities; or it is some obvious sign which experience has habitually coupled with a consequence, such as, for the dog, the sight of his master's hat on and the master's going out.