muscular effort is reducible to the twofold perception of a greater number of peripheral sensations, and of a qualitative change occurring in some of them.
The same definition of intensity applies to superficial efforts, deep-seated feelings and states intermediate between the two.
We are thus led to define the intensity of a superficial effort in the same way as that of a cases there is a qualitative progress and an increasing complexity, indistinctly perceived. But consciousness, accustomed to think in terms of space and to translate its thoughts into words, will denote the feeling by a single word and will localize the effort at the exact point where it yields a useful result: it will then become aware of an effort which is always of the same nature and increases at the spot assigned to it, and a feeling which, retaining the same name, grows without changing its nature. Now, the same illusion of consciousness is likely to be met with again in the case of the states which are intermediate between superficial efforts and deep-seated feelings. A large number of psychic states are accompanied, in fact, by muscular contractions and peripheral sensations. Sometimes these superficial elements are co-ordinated by a purely speculative idea, sometimes by an idea of a practical order. In the first case there is intellectual effort or attention; in the second we have the emotions which may be called violent or acute: anger, terror, and certain varieties of joy, sorrow, passion and desire. Let us show briefly that the same definition of intensity applies to these intermediate states.
The intermediate states. Attention and its relation to muscular contraction.
Attention is not a purely physiological phenomenon, but we cannot deny that it is accompanied by movements. These movements are neither the cause nor the result of the phenomenon; they are part of it, they express it in terms of space, as Ribot has so remarkably proved.7 Fechner had already reduced the effort of attention in a sense-organ to the muscular feeling "produced by putting in motion, by a sort of reflex action, the muscles which are correlated with the different sense organs." He had noticed the very distinct sensation of tension and contraction of the scalp, the pressure from without inwards over the whole skull, which we experience when we make a great effort to recall something. Ribot has studied more closely the movements which are characteristic of voluntary attention. "Attention contracts the frontal muscle: this muscle ... draws the eyebrow towards itself, raises it and causes transverse wrinkles on the forehead.... In extreme cases the mouth is opened wide. With children and with many adults eager attention gives rise to a protrusion of the lips, a kind of pout." Certainly, a purely psychic factor will always enter into voluntary attention, even if it be nothing more than the exclusion by the will of all ideas foreign to the one with which the subject wishes to occupy himself. But, once this exclusion is made, we believe that we are still conscious of a growing tension of soul, of an immaterial effort which increases. Analyse this impression and you will find nothing but the feeling of a muscular contraction which spreads over a wider surface or changes its nature, so that the tension becomes pressure, fatigue and pain.
The intensity of violent emotions as muscular tension.
Now, we do not see any essential difference between the effort of attention and what may be The intensity called the effort of psychic tension: acute desire, uncontrolled anger, passionate love, violent hatred. Each of these states may be reduced, we believe, to a system of muscular contractions co-ordinated by an idea; but in the case of attention, it is the more or less reflective idea of knowing; in the case of emotion, the unreflective idea of acting. The intensity of these violent emotions is thus likely to be nothing but the muscular tension which accompanies them. Darwin has given a remarkable description of the physiological symptoms of rage. "The action of the heart is much accelerated.... The face reddens or may turn deadly pale. The respiration is laboured, the chest heaves, and the dilated nostrils quiver. The whole body often trembles. The voice is affected. The teeth are clenched or ground together and the muscular system is commonly stimulated to violent, almost frantic action. The gestures ... represent more or less plainly the act of striking or fighting with an enemy."8 We shall not go so far as to maintain, with Professor James,9 that the emotion of rage is reducible to the sum of these organic sensations: there will always be an irreducible psychic element in anger, if this be only the idea of striking or fighting, of which Darwin speaks, and which gives a common direction to so many diverse movements. But, though this idea determines the direction of the emotional state and the accompanying movements, the growing intensity of the state itself is, we believe, nothing but the deeper and deeper disturbance of the organism, a disturbance which consciousness has no difficulty in measuring by the number and extent of the bodily surfaces concerned. It will be useless to assert that there is a restrained rage which is all the more intense. The reason is that, where emotion has free play, consciousness does not dwell on the details of the accompanying movements, but it does dwell upon them and is concentrated upon them when its object is to conceal them. Eliminate, in short, all trace of organic disturbance, all tendency towards muscular contraction, and all that will be left of anger will be the idea, or, if you still insist on making it an emotion, you will be unable to assign it any intensity.
Intensity and reflex movements. No essential difference between intensity of deep-seated feelings and that of violent emotions.
"Fear, when strong," says Herbert Spencer, "expresses itself in cries, in efforts to escape, in palpitations, in tremblings."10 We go further, and maintain that these movements form part of the terror itself: by their means the terror becomes an emotion capable of passing through different degrees of intensity. Suppress them entirely, and the more or less intense state of terror will be succeeded by an idea of terror, the wholly intellectual representation of a danger which it concerns us to avoid. There are also high degrees of joy and sorrow, of desire, aversion and even shame, the height of which will be found to be nothing but the reflex movements begun by the organism and perceived by consciousness. "When lovers meet," says Darwin, "we know that their hearts beat quickly, their breathing is hurried and their faces flushed."11 Aversion is marked by movements of repugnance which we repeat without noticing when we think of the object of our dislike. We blush and involuntarily clench the fingers when we feel shame, even if it be retrospective. The acuteness of these emotions is estimated by the number and nature of the peripheral sensations which accompany them. Little by little, and in proportion as the emotional state loses its violence and gains in depth, the peripheral sensations will give place to inner states; it will be no longer our outward movements but our ideas, our memories, our states of consciousness of every description, which will turn in larger or smaller numbers in a definite direction. There is, then, no essential difference from the point of view of intensity between the deep-seated feelings, of which we spoke at the beginning, and the acute or violent emotions which we have just passed in review. To say that love, hatred, desire, increase in violence is to assert that they are projected outwards, that they radiate to the surface, that peripheral sensations are substituted for inner states: but superficial or deep-seated, violent or reflective, the intensity of these feelings always consists in the multiplicity of simple states which consciousness dimly discerns in them.
Magnitude of sensations. Affective and representative sensations.
We have hitherto confined ourselves to feelings and efforts, complex states the intensity of which does not absolutely depend on an external cause. But sensations seem to us simple states: in what will their magnitude consist? The intensity of sensations varies with the external cause of which they are said to be the conscious equivalent: how shall we explain the presence of quantity in an effect which is inextensive, and in this case indivisible? To answer this question, we must first distinguish between the so-called affective and the representative sensations. There is no doubt that we pass gradually from the one to the other and that some affective element enters into the majority of our simple representations. But nothing prevents us from isolating this element and inquiring separately, in what
