I think that, from the fundamental identity of life-stuff, or protoplasm, in all forms of animal life, and from the observed similarity of nerves and nerve-cells when nervous tissue has been developed, and again from the essential resemblance of life-processes in all animal organisms, we are justified in believing that mental or conscious processes, when they emerge, are essentially similar in kind. Exactly when they do emerge in the ascending branches of the great tree of animal life it is exceedingly difficult, if not quite impossible, to determine. And it is, I fancy, quite impossible for us so to divest ourselves of the complexity of human consciousness as to imagine what the simplicity of the emergent consciousness in very lowly organisms is like. But I think that we may fairly believe that some dim form of discrimination is the germ from which the spreading tree of mind shall develop.[GE]
I assume, then, that, granting the theory of evolution, the early stages of the process of construction—discrimination, localization, and outward projection—are the same in kind throughout the whole range of animal life, wherever we are justified in surmising that psychical processes occur, and the power of registration and revival in memory has been established. As will be gathered, however, from what I have already said, I hold that the nature of the constructs produced is and must be for us human-folk, since we are human-folk, to a large extent a matter of speculation. Remembering this, then, endeavouring never to lose sight of it for a moment, let us consider what we may fairly surmise concerning the constructs and the process of construction in animals.
There can be no question that the animals nearest us in the scale of life—the higher mammalia—form constructs analogous to, if not closely resembling, ours. I do not think the resemblance can be in any sense close, seeing to how large an extent our constructs are literally our handi-work. For though in many animals the tongue and lips are delicate organs of touch—not to mention the trunk of the elephant—and though in the monkeys and many rodents the hands are used for grasping, still we have no reason to suppose that in any other mammal the geometrical sense of touch plays so determining a part in the formation of constructs as in man. On the other hand, in the dog and the deer, for example, not only must the marvellously acute sense of smell have a far higher suggestive value, but smells and odours must, one would suppose, be built into the constructs in a far larger proportion. But although their constructs may not closely resemble ours, the constructs of animals may, I believe, be fairly regarded as closely analogous to our own. And as with us, so with them, a comparatively simple and meagre suggestion may give rise, through association in experience, to the construction of a complex object. And again, as with us, so with them, the suggested construct may be very vague and indefinite.
A dog, for example, is lying asleep upon the mat, and hears an unfamiliar step in the porch without. There can be no question that this suggests the construct man. But from the very nature of the case, this must be vague and indefinite. So, too, when a chamois, bounding across the snow-fields, stops suddenly when he scents the distant footprints of the mountaineer, the construct that he forms cannot be in any way particularized—no more particularized than is to me the sheep that I hear bleating in the meadow behind yonder wall.
And no one is likely to question the fact that animals habitually proceed from this first stage—the formation of constructs by immediate association—to the second stage of construction—the defining of constructs by examination. In many of the deer tribe, notably the prong-horn of America, this tendency is so strongly developed that they may be lured to their destruction by setting up a strange and unfamiliar object which, as we put it, may excite their curiosity. A strange noise or appearance will make a dog uneasy until he has by examination satisfied himself of the nature of that which produces it. Of this an instance fell under my observation a few days ago. My cat was asleep on a chair, and my little son was blowing a toy horn. The cat, without moving, mewed uneasily. I told my boy to continue blowing. The cat grew more uneasy, and at last got up, stretched herself, and turned towards the source of discomfort. She stood looking at my boy for a minute as he blew. Then curling herself up, she went to sleep again, and no amount of blowing disturbed her further. Similarly, Mr. Romanes's dog was cowed at the sound of apples being shot on to the floor of a loft above the stable; but when he was taken to the place, and saw what gave rise to the sound, he ceased to be disquieted by it. Every one must have seen animals defining their constructs by examination. A monkey will spend hours in the examination of an old bottle or a bit of looking-glass. At the Zoological Gardens connected with the National Museum at Washington, a monkey was observed with a female opossum on his knee. He had discovered the slit-like opening of the marsupial pouch, and took out first one and then another of the young, looked them over carefully, and replaced them without injury.[GF]
There may possibly be some difference of opinion as to whether animals are able to infuse into their constructs of other animals the element of feeling. One would, perhaps, fain believe that the beasts of prey were wholly unaware of the pain they inflict on other organisms. But I question whether any close observer of animals could hold this view. Even if it were supposed that when two dogs fight they are blind to the pain they are inflicting on each other, their mock-fighting seems to imply a consciousness of the pain they might inflict, but avoid inflicting. And many of us have presumably had experiences analogous to the following: A favourite terrier of mine was once brought home to me so severely gashed in the abdominal region that I felt it necessary to sew up the wound. In his pain the poor dog turned round and seized my hand, but he checked himself before the teeth had closed upon me tightly, and piteously licked my hand. For myself, I cannot doubt that animals project into each other the shadows of the feelings of which they are themselves conscious.
The fact that dogs may be deceived by pictures[GG] shows that they may be led through the sense of sight to form false constructs, that is to say, constructs which examination shows to be false. Through my friend and colleague, Mr. A. P. Chattock, I am able to give a case in point. I quote from a letter received by Mr. Chattock: "Your father asks me to tell you about our old spaniel Dash and the picture. I remember it well, though it must be somewhere, about half a century ago. We had just unpacked and placed on the old square pianoforte, which then stood at the end of the dining-room, the well-known print of Landseer's 'A Distinguished Member of the Humane Society.' When Dash came into the room and caught sight of it, he rushed forward, and jumped on the chair which stood near, and then on the pianoforte in a moment, and then turned away with an expression, as it seemed to us, of supreme disgust."
I think we may say, then, that the higher animals are able to proceed a long way in the formation and definition of highly complex constructs analogous to, but probably differing somewhat from, those which we form ourselves. These constructs, moreover, through association with reconstructs or representations, link themselves in trains, so that a sensation or group of sensations may suggest a series of reconstructs or a series of remembered phenomena. We here approach the question of inferences, of which more anon. But in this connection passing reference may be made to the phenomena of dreaming. Dogs and some other animals undoubtedly seem to dream.
The nature of dreaming may, perhaps, be best illustrated by a rough analogy. Professor Clifford likened the human consciousness to a rope made up of a great number of occasionally interlacing strands. Let us picture such a rope floating in water. Much of it is submerged; only the upper part is visible at the surface. This upper part is like the series of mental phenomena of which we are distinctly conscious. Below this lie other series in the half-submerged state of subconsciousness. Deeper still lie unconscious physiological processes capable of emerging into the shadow of subconsciousness or the light of distinct consciousness. Now picture this rope gradually slipping round as it floats, so that now one part, now another, sees the light. This is analogous to the musing state, when we allow our thoughts to wander unchecked by any effort of attention. Attention is the faculty by which we steady the rope, so that one particular strand is kept continuously uppermost. The inattentive mind is one in which the rope keeps slipping round and refuses to be steadied in this manner; and in unquiet sleep, when the faculty of attention is dormant, the strands come quite irregularly and haphazard to the surface, and we have the phantasmagoria of dreams.