I
Those who have not carefully followed the history of scientific progress think that the theory of evolution is solely Darwin’s work. The same thing has happened as after a victory, when public opinion lauds the name of a single general, whereas the action of others was no less efficacious and decisive in winning the battle. But in this case it would be an injustice not to award the greatest praise to Herbert Spencer, whom Darwin himself called 'the great expounder’ of the principle of evolution. So soon as 1855, in the first edition of his 'Principles of Psychology,’ Spencer maintains the doctrine of evolution, when, as he says, it was 'ridiculed in the world at large and frowned upon in the scientific world.’
In the second edition of his 'Principles of Psychology,’ Spencer added a chapter entitled, 'The Language of the Emotions,’ which is of great value to us, as it was printed a few months before Darwin published his book, 'The Expression of the Emotions.’
One of the most important ideas, physiologically speaking, which Spencer has formulated is the following: 'The molecular motion disengaged in any nerve-centre by any stimulus, tends ever to flow along lines of least resistance throughout the nervous system, exciting other nerve-centres, and setting up other discharges. The feelings of all orders, moderate as well as strong, which from instant to instant arise in consciousness, are the correlatives of nerve-waves continually being generated and continually reverberating throughout the nervous system—the perpetual nervous discharge constituted by these perpetually-generated waves, affecting both the viscera and the muscles, voluntary and involuntary.’
The ideas developed by Darwin on the origin of the expressions have such a striking resemblance, even identity, with Spencer’s doctrine, that Darwin felt himself obliged to make the following declaration in a foot-note: 'I may state, in order that I may not be accused of trespassing on Mr. Spencer’s domain, that I announced in my “Descent of Man” that I had then written a part of the present volume.’[21]
The origin of the movements of expression, as propounded by Spencer and more amply developed by Darwin in his book, does not convince me. The profound admiration which I cherish for these two great masters has made me timid in deviating from their path, but since the facts which presented themselves to me during my studies have convinced me that the same results might be obtained in another way, it is my duty to communicate those observations and experiments which point to another solution of the problem.
I shall here quote a passage from Spencer’s 'Language of the Emotions,’ thus drawing, as we say, from the well of the great philosopher himself.
'Throughout the animal kingdom, non-pleasurable feelings are most frequently and most variously excited during antagonism. Among inferior types of creatures antagonism habitually implies combat, with all its struggles and pains. Though in man there are many sources of non-pleasurable feelings other than antagonism, and though antagonism itself ends in combat only when it rises to an extreme, yet as among inferior ancestral types antagonism is the commonest and most conspicuous accompaniment of non-pleasurable feeling, and continues to be very generally an accompaniment in the human race, there is organically established a relation between non-pleasurable feeling and the muscular actions which antagonism habitually causes. Hence those external concomitants of non-pleasurable feeling which constitute what we call its expression, result from incipient muscular contractions of the kinds accompanying actual combat.
'But how does this explain the first and most general mark of non-pleasurable feeling—a frown? What have antagonism and combat to do with that corrugation of the brow which, when slight, may indicate a trifling ache or a small vexation, and when decided, may have for its cause bodily agony, or extreme grief, or violent anger? The reply is not obvious, and yet, when found, is satisfactory.
'If you want to see a distant object in bright sunshine, you are aided by putting your hand above your eyes; and in the tropics, this shading of the eyes to gain distinctness of vision is far more needful than here. In the absence of shade yielded by the hand or by a hat, the effort to see clearly in broad sunshine is always accompanied by a contraction of those muscles of the forehead which cause the eyebrows to be lowered and protruded; so making them serve as much as possible the same purpose that the hand serves.... Now if we bear in mind that during the combats of superior animals, which have various movements of attack and defence, success largely depends on quickness and clearness of vision ... it will be manifest that a slight improvement of vision, obtained by keeping the sun’s rays out of the eyes, may often be of great importance, and where the combatants are nearly equal, may determine the victory.... Hence, we may infer that during the evolution of those types from which man more immediately inherits, it must have happened that individuals in whom the nervous discharge accompanying the excitement of combat, caused an unusual contraction of these corrugating muscles of the forehead, would, other things equal, be the more likely to conquer and to leave posterity—survival of the fittest tending in their posterity to establish and increase this peculiarity.’
If this interpretation of Spencer, which Darwin expanded, were true, the consequences would be, that in the long succession of generations animals would have gradually rid themselves of that which is injurious and fatal to them. But this law does not verify itself in the least, rather do we see, in studying violent emotions, that the more serious the danger the greater is the predominance both in number and strength of injurious phenomena. We have already seen that trembling and cataplexy render us unable to flee or defend ourselves, and we shall now be convinced that in critical moments we see less distinctly than when we are tranquil.
In the face of these facts we must admit that not all phenomena of fear can be explained by the theory of selection. In their extreme degrees they are morbid phenomena indicating an imperfection of the organism. One might almost say that nature had not been able to find a substance for brain and spinal cord which should be extremely sensitive, and yet should never, under the influence of exceptionally strong stimuli, exceed in its reaction those physiological limits which are best adapted to the preservation of the animal.
But before we go further, let us consider those facts which seem to contradict the hypothesis of Spencer and Darwin.