Chapter 16
Description Of The Faculty Of Phantasy
350. So far we have considered the fundamental feeling and those modifications of the fundamental feeling which constitute the external sensitivity of animals. However, the feeling is also subject to the modifications of the phantasy which we must now try to describe. The marvellous power of our imagination enables us to reproduce or re-excite previous sensations so vividly that it is sometimes impossible to distinguish them from the sensations themselves. This is especially the case in dreams, mental illness and imaginary visions.
351. First, we must try to clarify the concept of this renewal of sensation which the soul, through its own power, can arouse internally. Let us, therefore, consider the nerve filaments as though they had two extremities. The exterior extremity extends all over the surface of the body, and terminates in its sensitive endings under the epidermis, in the skin. The interior extremity will probably end in the brain or spinal cord, or anywhere we care to place it. The law which governs the awakening of sensation in the animal states: `An oscillation, or trembling, or movement of some sort must take place in the nerve filament or sensory substance before the sensation can occur.' This movement or disturbance of the substance may be caused by two kinds of stimuli, one beginning at the outer extremity of the nerve, the other at the inner extremity. In the first case, exterior bodies stimulate the nerve from outside and produce feelable impressions; in the second case, the stimulus is the soul's own activity which has the power to move the sensory organs and to communicate movement to the outer extremity. If this action of the soul produces in the nerve a vibration or alteration similar to that produced by the exterior stimulus, a feeling will arise similar to that of the sensation already experienced. The root of this phenomenon is to be found in the law of parallelism (which we have already described) between the extrasubjective movements of certain parts of the body and sensations.
352. This way of conceiving the faculty of phantasy is the result of factual experience combined with induction. First, it is indeed a fact that the soul has the power to move parts of its own body. The parts it moves are not only the legs, arms, head and the trunk, but even tiny members - although it is not easy to see, without very careful attention, how movement proceeds from the soul in cases like these. Let us imagine that someone receives a letter bringing unexpected good news. It is the person's soul, his understanding, not his body, which perceives the joy of the occasion. But the rational soul does not keep the joy to itself: the heart beats faster, and the face glows. If the sudden news is bad, the face loses its colour, a sure sign that the soul has diminished the force it exercises on the heart and the arteries. This would explain why the soul produces extremely varied and complicated movements either directly in the nerves, or indirectly in organs which seem impervious to sensation. Sometimes this takes place where it would be least expected.(159) I have seen Giuseppe Bartolomeo Stoffella, a fellow townsman of mine, move his ears (as they say that Albino and that Mens, a Parisian surgeon(160) did) as a result of long practice. The aperture of the iris opens and closes instinctively to shelter the retina from exposure to excessive light and to take as much advantage as possible of dull light. But even this was learned and freely practised by Felice Fontana(161) and others.
353. I firmly believe, therefore, that `all the movements carried out instinctively in our bodies (that is, all those upon which we depend for life and action) could be carried out as the result of an act of our will'. This `exercise' of the soul, which produces some determinate movements rather than others, is an art learned as a result of practice. The soul must not only have the power to move the parts concerned, but must also acquire the habit of using it in such a way that the power can obey habitual instinct or even the command of free will.(162)
This is not the place to investigate how the soul learns the art of moving different parts of its body, or to examine the laws governing these voluntary movements. Here it is sufficient to know of the existence of the soul's power over different parts of the body in order to conclude inductively that the soul has the capacity for moving the nerves and the brain with the same movements as those accompanying sensations. In this way it reproduces the sensations, giving rise to what we call phantasies or images.
354. Another fact on which we may base our conjecture about the explanation of the soul's power of phantasy is the vividness and clarity of images produced by the phantasy, which we have already mentioned. These are often powerful enough to induce a firm conviction of the presence of the imagined object (cf. 350). Dr. Pinel, after describing a female visionary whom he had kept under observation for a long period, commented on the nature and effect of her imaginary visions and on her complete conviction that the things she saw were as real as those in everyday life. He concluded: `This is definitely not a mere memory. It is an instinctive knowledge, an interior fascination akin to that which would be stimulated by a vivid impression on the organ of sight.'(163) The same fact occurs in dreams where normally we have no doubt whatsoever about the reality of what we see, do and think. Superstitions, especially idolatry, have their principal source in the phantasy power of our soul, and we can affirm truthfully that this faculty is the principal occasional cause of our errors.(164)
Notes
(159) A sudden fright is sufficient to turn the hair white, as one can see in Schenck and others who have described such cases. Fright also makes the hair stand on end. The soul, therefore, has the power even to affect the hair, which experiences life at a lower grade than other parts of the body.
(160) Cf. Le-Cat, Trattato de' sensi (2 vols. Paris, 1767), where the author proves that the ears can be moved, and maintains that only lack of practice impedes voluntary ear-wagging.
(161) Cf. Felice Fontana, De' moti dell'iride, a fine book. - I realise that the majority of modern anatomists deny the presence of muscles in the pupil. In this case, the will could not play any part in increasing or decreasing the pupil. According to these anatomists the enlargement of the pupil exposed to light is the result of an increase in the blood flow, due to the irritation produced by the light. But there is no doubt some individuals have been able to make the pupil diminish or expand at will. I am not saying that they used muscles to do this. I am simply stating a fact, which could also be explained by the power of the will over the supply of blood to the pupil.
(162) Roberti, in his delightful letter about a sixteen month-old child, describes how children learn the art of moving their eyes which, before the soul has taken control over them, are immobile and supine.
(163) Tratt. della alienazione mentale, sect. 2, 7. - Dr. Lorenzo Martini suggests that use of the imagination could explain the heat sometimes felt by a sick person despite the coldness of the skin. `It is not difficult to explain this phenomenon. It is subject to the laws of the imagination. In order to have a sensation in the first place, some power must either make itself felt or withdraw its pressure. Later, the same movements can be renewed in the common sensory, and the same perceptions awakened. A warmer body than our own acts upon the skin. The resulting impression sent to the common sensory enables the soul to experience a heat sensation. A cooler body now acts upon us in the same way, and our body loses some of its heat either in a part of its surface or all over. The soul is now conscious of a change in its state and feels the cold. The same movements can now be aroused later in the common sensory, the first group making us feel warm, the second cold. We need to note that the renewal of the cerebral, sensory movements, upon which the feeling of warmth or cold depends, are not noticeably willed, but result from some disorder' (Lezioni di fisiologia, lesson 77).
(164) Cf. Certainty, 1285-1298, on the seven occasional causes of error.