ABSTRACT
THE definition of the object is, as we have seen, that it exists partes extra partes, and that consequently it acknowledges between its parts, or between itself and other objects only external and mechanical relationships, whether in the narrow sense of motion received and transmitted, or in the wider sense of the relation of function to variable. Where it was desired to insert the organism in the universe of objects and thereby close off that universe, it was necessary to translate the functioning of the body into the language of the in-itself and discover, beneath behaviour, the linear dependence of stimulus and receptor, receptor and Empfinder.1 It was of course realized that in the circuit of behaviour new particular forms emerge, and the theory of specific nervous energy, for example, certainly endowed the organism with the power of transforming the physical world. But in fact it attributed to the nervous systems the occult power of creating the different structures of our experience, and whereas sight, touch and hearing are so many ways of gaining access to the object, these structures found themselves transformed into compact qualities derived from the local distinction between the organs used. Thus the relationship between stimulus and perception could remain clear and objective, and the psycho-physical event was of the same kind as the causal relations obtaining ‘in the world’. Modern physiology no longer has recourse to these pretences. It no longer links the different qualities of one and the same sense, and the data of different senses, to distinct material instruments. In reality injuries to centres and even to conductors are not translated into the loss of certain qualities of sensation or of certain sensory data, but into loss of differentiation in the function. We have already discussed this: wherever the seat of the injury in the sensory routes and whatever its origin, one observes, for example, a decay of sensitivity to colour; at the beginning, all colours are affected, their basic shade remaining the same,
but their saturation decreasing; then the spectrum is simplified and reduced to four colours: yellow, green, blue, crimson, and indeed all short-wave colours tend towards a kind of blue, all long-wave colours towards a kind of yellow, vision being liable, moreover, to vary from mė ment to moment, according to degree of fatigue. Finally a monochrome stage in grey is reached, although favourable conditions (contrast, long exposure) may momentarily bring back dichromic sight.1 The progress of the lesion in the nervous tissue does not, therefore, destroy, one after another, ready-made sensory contents, but makes the active differentiation of stimuli, which appears to be the essential function of the nervous system, increasingly unreliable. In the same way, in the case of noncortical injury to the sense of touch, if certain contents (temperatures) are more easily destroyed and are the first to disappear, this is not because a determinate region, lost to the patient, enables us to feel heat and cold, since the specific sensation will be restored if a sufficiently extensive stimulus is applied;2 it is rather that the sensation succeeds in taking its typical form only under a more energetic stimulus. Central lesions seem to leave qualities intact; on the other hand they modify the spatial organization of data and the perception of objects. This is what had led to the belief in specialized gnosic centres for the localization and interpretation of qualities. In fact, modern research shows that central lesions have the effect in most cases of raising the chronaxies, which are increased to two or three times their normal strength in the patient. The excitation produces its effects more slowly, these survive longer, and the tactile perception of roughness, for example, is jeopardized in so far as it presupposes a succession of circumscribed impressions or a precise consciousness of the different positions of the hand.3 The vague localization of the stimulus is not explained by the destruction of a localizing centre, but by the reduction to a uniform level of sensations, which are no longer capable of organizing themselves into a stable grouping in which each of them receives a univocal value and is translated into consciousness only by a limited change.4 Thus the excitations of one and the same sense differ less by reason of the material instrument which they use than in the way in which the elementary stimuli are spontaneously organized among themselves, and this organization is the crucial factor both at the level of sensible ‘qualities’ and at that of perception. It is this, and not the specific energy of the nervous apparatus examined, which causes an excitant to give rise to a tactile or thermic sensation. If a given area of skin is several times stimulated with a hair, the first perceptions are clearly distinguished and localized each time at the same point. As the stimulus is repeated, the localization becomes less precise, perception widens in space, while at the same time the sensation ceases to be
specific: it is no longer a contact, but a feeling of burning, at one moment cold and at the next hot. Later still the-patient thinks the stimulus is moving and describing a circle on his skin. Finally nothing more is felt.1 It follows that the ‘sensible quality’, the spatial limits set to the percept, and even the presence or absence of a perception, are not de facto effects of the situation outside the organism, but represent the way in which it meets stimulation and is related to it. An excitation is not perceived when it strikes a sensory organ which is not ‘attuned’ to it.2 The function of the organism in receiving stimuli is, so to speak, to ‘conceive’ a certain form of excitation.3 The ‘psychophysical event’ is therefore no longer of the type of ‘worldly’ causality, the brain becomes the seat of a process of ‘patterning’ which intervenes even before the cortical stage, and which, from the moment the nervous system comes into play, confuses the relations of stimulus to organism. The excitation is seized and reorganized by transversal functions which make it resemble the perception which it is about to arouse. I cannot envisage this form which is traced out in the nervous system, this exhibiting of a structure, as a set of processes in the third person, as the transmission of movement or as the determination of one variable by another. I cannot gain a removed knowledge of it. In so far as I guess what it may be, it is by abandoning the body as an object, partes extra partes, and by going back to the body which I experience at this moment, in the manner, for example, in which my hand moves round the object it touches, anticipating the stimuli and itself tracing out the form which I am about to perceive. I cannot understand the function of the living body except by enacting it myself, and except in so far as I am a body which rises towards the world.
