Hence the extraordinary and beautiful sympathy of the dog. How largely sympathy depends on the appreciation of objective signs, we know among ourselves. The sympathetic man notices every varying expression and shadow of a shade. The unsympathetic person needs to have the fact that one is suffering or depressed shouted in his ear. The sympathy of the dog, so different from the behaviour of all but exceptional cats, is due to his keen receptivity and his social antecedents. The impression produced by every movement of his master is fringed with sentience. But there need be no reflective distribution of this sentience between subject and object. I am not denying that in the dog this reflective distribution may perhaps be superadded. But I submit that the evidence we have of sympathy in animals does not carry with it, as a necessary inference, that they have such powers of reflection and conceptual thought.

CHAPTER XVIII.

THE EVOLUTION OF CONSCIOUSNESS.

E have, so far, taken for granted the existence of

WE have; so far, and the fact that there are subjective

phenomena which we, as comparative psychologists, may study. We have also proceeded throughout on the assumption that subjective phenomena admit of a natural interpretation, as the result of a process or processes of development or evolution, in just the same sense as objective phenomena admit of such interpretation. The question now arises: If consciousness exists, and if consciousness, as we know it, has been evolved, from what has it been evolved? It must be freely and frankly admitted that any suggestion which the comparative psychologist has to make, in attempting to answer such a question, must be speculative. But we must not be afraid of speculation so long as it is on scientific lines, and so long as the basis of speculation is honestly and fearlessly laid bare, and not slurred over and beclouded by ambiguous phraseology. Speculation is but the play of the imagination along the fringe which borders our knowledge; and imagination is the mother of insight.

It has before been pointed out that one of the cardinal steps in making our psychology comparative, and in linking this branch of science with those branches which deal with the objective aspects of our knowledge, is the correlation of psychical phenomena with physiological phenomena. It would be as idle as it would be disingenuous to pretend that this correlation had as yet been carried far. From the nature of the case, the difficulties of investigation are enor

mous. And much of the experimentation in physiological psychology-valuable as it undoubtedly is-deals with questions which are mainly physiological, and hardly touch psychology at all. But such work as has been done tends to strengthen and not to weaken the validity of the assumption; and, further, suggests that in and through this correlation we may seek a yet wider correlation of that which objectively we know as energy, and that which subjectively we know as consciousness.

Let us, however, put the matter in more concrete form. The dog that, as I write, looks up in my face with eyes so full of affection and of intelligence, suggests a double problem. How has that organic frame, with the bright brown eye and the warm active brain, been evolved, and from what? How has that keen intelligence and the consciousness it implies been evolved, and from what? We may look at the matter first and chiefly from the point of view of the development of the individual (ontogenesis).

In the common course of generation the dog is developed from a minute egg-cell, one hundredth of an inch or less in diameter, with which a yet more minute sperm has entered into fertile union. Supplied with shelter, warmth, and nutriment, by that maternal self-sacrifice which is a deeply significant fact of organic nature, this little speck of living stuff passes, by a process strictly continuous, though profoundly modified by the catastrophe of birth, into the dog, with its wealth of intelligence and affection. It is surely impossible, without extravagance, to speak of the fertilized ovum as conscious. Where, then, in the continuous process of development does consciousness come in? How, and whence ? We are not now-a-days to be put off with the ambiguous assertion that consciousness and intelligence are "potentially" present in the germ. We ask: What is actually present therein as the basis of this potentiality? And if we are told that consciousness dawns at, or shortly after, the

catastrophe of birth, then again we ask: Whence comes this dawning consciousness, and by what means does it become associated with the puppy's brain?

Having thus opened up these several questions, all of like implication, let us now endeavour to set forth the answer which seems most closely in accordance with scientific analogies. And to this end let us consider the living dog. His frame is pulsating with life and restless activity, and somehow associated with the transformations of energy in that brain of his there are states of consciousness. Were his skin, and the walls of his skull, as transparent as glass; did the molecular vibrations of his brain lie open to our curious scrutiny; could we trace in detail all the varied and orderly transformations of energy of which that brain is the theatre, the accompanying consciousness would still be beyond our reach. We might follow the changes of energy; he alone would feel the states of consciousness. Now suppose that the dog dies. His body lies before us stiff with the rigor mortis. If we had weighed it previous to death, and if we were to weigh it again after death, the scales would give us no information of the departure of anything material. All signs of consciousness, however, are gone. And could we see through skin and skull into the brain, which during life was the theatre of so complex and orderly a sequence of transformations of energy, we should find that it was still and motionless. We are therefore justified in saying that, omitting minor qualifications, the orderly transformations of energy in the brain and the concomitant consciousness cease together at death. Closely associated during life, varying together in health and sickness, ceasing together at death, what is the nature of their connection?

Let us regard the matter from the objective aspect first, from the side to which the occurrences present themselves as transformations of energy. The state of consciousness being ex hypothesi accompanied by certain molecular vibra

tions in the brain or some part thereof, we have to note that from the physical point of view these molecular vibrations constitute an exceedingly complex and orderly mode of energy. It is upon this energy that we must fix our attention, the material structure of the brain being what we may call the vehicle of its manifestation. We are too apt to regard the structure as the essential thing on which to concentrate our mental gaze, partly, no doubt, because, through the invaluable labour of microscopists, we know so much that is definite about this structure. But a more penetrating insight enables us to see that the structure is merely the necessary basis of what is the really important thing-the manifestation of energy. The material structure of a steamengine is of importance. But why? Because it is the vehicle for the performance of work. That is the really essential part of the business. In like manner nerve-structure is of importance. But why? Because it is the vehicle for the complex and orderly manifestation of energy. The essential importance of looking at the going machine, at the performance of work, at the energy of the matter in motion, not merely the material structure that is moved,— the essential importance, I say, of fixing our attention on this, being fairly grasped, we may now proceed to inquire from what the complex and orderly vibrations of the dog's brain have been evolved. In the fertilized ovum from which the dog was developed (and the same is true of the amoeboid ancestor from which, hypothetically, the race of dogs has been evolved), there is certainly nothing approaching the orderly complexity of these molecular vibrations. But there are simpler organic modes of motion from which these complex molecular vibrations have arisen by a continuous process of development. It is from these simpler modes of energy in the simpler organic substance of the ovum that the more complex modes of energy which characterize the workings of the dog's brain have been evolved. In the