The first view seems to number most adherents. It assumes as a fundamental fact the grasping of a contrast between two perceptions, images, or ideas. Yet all contradictory contrasts do not make us laugh; if they are to do so, they must fulfil certain conditions. In the first place, the two contradictory elements must be given simultaneously as belonging to the same object, so as to induce us to think that a thing both is and is not at the same time. A monkey makes us laugh, because he reminds us of, but is not, a man; he makes us laugh still more if dressed in human clothes, because the contradiction is more striking. Next, the two states of consciousness must be very nearly of the same mass and intensity—a broken-down old man carrying a heavy burden does not make us laugh. “The two contradictory forces brought into play in laughter, being unable to attain to the unity of a conception, are forced to escape outwards by an expenditure of muscular energy” (L. Dumont).
The second theory, first formulated by Hobbes, but perhaps of still earlier date, is as follows: “The passion of laughter is nothing else but sudden glory arising from sudden conception of some eminency in ourselves by comparison with the infirmity of others or with our own formerly.”[[222]] The partisans of this view have severely criticised the theory of incongruity, or discordance in things. “An instrument out of tune, a fly in ointment, snow in May, Archimedes studying geometry in a siege; ... everything of the nature of disorder; ... and whatever is unnatural; the entire catalogue of the vanities given by Solomon—are all incongruous, but they cause feelings of pain, anger, sadness, loathing, rather than mirth.”[[223]] This view is quite as open to criticism as the preceding; and we might enumerate a long list of cases where the feeling of superiority, whether justifiable or not, does not make us laugh. In my opinion, both views ought to be admitted, as being partially true, and meeting distinct cases.
The second theory is suited to the primitive and lower form of that emotional state which shows itself in laughter. In the case before us, this state is directly derived from the sense of strength or power, or, as Hobbes calls it, glory; the contradictory contrast, if perceived at all, is in the background. The coarsest and most brutal, almost physiological, expression of this mental state, is the laugh of the savage after a victory, when treading his vanquished enemy under foot.
“It appears to be fairly certain, not only that laughter is a concomitant of brutality and cruelty among uncivilised races, and children, but that even in the cases of the more refined and benevolent, it is apt to accompany the recognition of any slight loss of dignity in another, when this loss does not evoke other and painful feelings.”[[224]] It is a matter of common observation, that many people have a tendency immediately to burst out laughing at any accident, even if serious, happening to others; and this instinctive laughter certainly does not spring from the good side of human nature. It is clear that, under this form, laughter has nothing to do with æsthetics.
The theory of discord suits well with the secondary and superior forms: the feeling of superiority becomes effaced and passes into the background. It is an intellectualised manifestation, which has or may have an æsthetic value, the mental development permitting those fugitive and subtle contradictions which constitute the principal element of the comic to be caught on the wing. It takes on an almost disinterested character, though never, perhaps, completely losing its original blemish.
Finally, laughter may take a still more elevated form in the humorous spirit we have already mentioned (Part II., Chap V., 3), in which the feeling of superiority is mitigated by a large proportion of sympathy.
2. The nature of laughter would be very incompletely known were we to confine ourselves to pure psychology, but the physiological study of this phenomenon has not been neglected. The description will be found in special works on the expression of the emotions, especially in Darwin (chap. viii.). Laughter is a strengthened expiratory movement; when prolonged, the excess of the expirations over the inspirations necessitates deep sighs in order to restore the equilibrium; there is a drawing back and raising of the corners of the mouth, the eyes become brighter through the quickening of the circulation. According to Darwin, the uninterrupted gradation from violent laughter (which in all human races is accompanied by tears) to moderate laughter, a broad smile and a gentle smile, proves their common nature; but is laughter the complete development of the smile, or the smile a modified form of the noisy laughter of the first period? Evolutionists are, in general, inclined to consider noisy laughter as the primary form, connected with the brutal sense of superiority. Yet the early appearance of the smile in infants, at about two months, while laughter is not observed, as a rule, till the fourth month, seems, on this theory, to contradict the principle that the evolution of the individual reproduces, in an abridged and accelerated form, the evolutionary process of the species. On the other hand, animals do not give us any information on this point. Certain monkeys smile or laugh—i.e., the corners of the mouth are drawn back, their eyes become brilliant, and they emit a certain sound approximating to a chuckle (Darwin, Wallace, Mantegazza, etc.).
But the important point is to know why this collection of physiological facts is connected with certain mental dispositions. If laughter were the constant and exclusive expression of joy and pleasure, the answer would be easy; as in addition to this it is sometimes morbid, sometimes futile and simply physiological, the explanation ought to be framed to include all these cases.
Herbert Spencer has proposed one, which, though published some time ago (1863), still remains one of the most satisfactory. In his view[[225]] laughter is due to a sudden diversion of nervous energy into a new path—an overflow-channel. The excitation of the nervous system existing at any given moment, especially if intense, can only be expended in three ways—either by transmission to some other part of the cerebro-spinal organism, exciting other feelings or thoughts; or by acting on the viscera, the heart, lungs, and digestive organs; or else by producing muscular movements; and, as the nervous discharge, especially if moderate, follows the line of least resistance, and the most easily moved muscles are the first to be shaken, it acts on the vocal organs, on the mouth, and on the face. Laughter is connected with this last line of action.
It may result from purely physical excitants: tickling, cold, toxic action, sudden relaxation after a long period of constraint.