CHAPTER 14

The extrasubjective perception of bodies by means of
the five senses considered in their mutual relationship

941. Sensations of smell and taste have a very confused extrasubjective perception and consequently cannot serve as signs indicating distant bodies. The distinct perception of distant bodies comes from the differences we perceive in their size and shape. Smell and taste particles striking the relevant organs do not follow any law of proportion to the size and shape of external things. However they do help in some way. We habitually note, for example, that the scent of a flower disappears when the flower is taken away. The scent becomes for us an indication of the fragrant object which it recalls because the scent-sensation is associated with the idea of the body also known through touch and sight. Although taste and smell are not by nature signs indicating bodies present to our touch, artificially they can become signs indicating anything or any thought.

942. The same can be said about sounds which, however, lend themselves far more effectively to intelligent use in the formation of languages.

943. Sight-sensations on the other hand are arranged and ordered harmoniously by nature itself, as we have seen. Consequently they become signs, not of anything whatsoever or any thought, which demands ingenuity,(207) but of external bodies perceived by touch.
This occurs because of the relationship of the different sizes and shapes of sight-sensations with tactile bodies and their distances. The proportional sizes and shapes of sight-sensations represent perfectly the size and shape of bodies we can touch but, through long habit, are no longer considered as signs of the sizes and shapes presented by touch. Instead, they become one with them and take their place. In this way the sizes and shapes given by sight become the space itself occupied by distant, external things. But various colours depict these signs and shapes which, if considered as external bodies, necessitate the projection also of the colours to outside objects. In a word, the coloured signs of the sizes and shapes received in our eye are taken as the sizes and shapes of the external things themselves, so that we consider as coloured the sizes and shapes of the external things we touch.

944. As a result we are not satisfied with calling the impressions on our eye signs of external things or signs indicating something. We prefer to call them images, as if the light, on bringing colours into our eye, first looked at the bodies and then, like a painter making a portrait, chose from them various tints, shadings and outlines to make its own creation.

945. After we have formed the habit of judging distant bodies by their colours so that bodies and colours can be reduced to the same space to form one thing (as far as we are concerned) (cf. 941-943), visual perception becomes attractive, pleasant, rapid, helpful, clear,(208) precise. It also attracts our attention much more than the immediate perception of bodies by feeling or touch and movement. We are so occupied with our visual perception that we no longer think about other ways of perceiving bodies, persuading ourselves that we know everything by our sight alone. What we cannot see, we do not know, and even touch-perception becomes blind and cumbersome for us.

946. Not only the mass of people but thinkers are subject to this error. Philosophers, who do not suddenly cease being ordinary people, allow themselves to be so charmed by the clarity and attraction of sight that they reduce all their arguments about perception and cognition of bodies to this single sense.

This is not my observation; it is Stewart's. He says:

947. By describing our perceptions of bodies through the sense of sight, we are using metaphorical, not proper language.(210) The result is infinite errors and any number of useless, inexplicable problems which, when the language is corrected, disappear as rapidly as empty superstitions in the minds of people who are receiving religious instruction [App., no. 38].

948. Aristotle and the Scholastics said that we do not perceive things themselves but their likenesses, stamped on our organs and then received into our spirit by means of the organs.
I believe that these likenesses or sensible species originate from the above-mentioned errors, that is, from applying to sensitivity in general what happens solely in our sense of sight.
If these philosophers had carefully analysed the action of each sense, they would not have made common to all the other senses, what is proper to the most noble and beautiful sense. Each sense would have been described by words proper and adapted to it.
According to their analysis, only touch, out of the five senses,(211) perceives bodies immediately.

But we have also seen that the senses of sight, hearing, smell and taste manifest two very different functions. The first is that they are all touch: they make us perceive immediately the bodies touching them. These bodies, although minute and innumerable, leave a lively but confused perception of themselves. The second function of these particular senses is totally different: it arises because we use the sensations brought to us by the touch-function of these senses as signs to know other external bodies situated at a distance from these organs. The sense of sight by its nature performs this function much better than the other senses.
Sensations of sight, as signs indicating distant bodies, can be very suitably called species or visual species so as not to confuse them with ideas. The word itself, species, means in Latin sight, look, aspect.

949. However, as I said, these species of bodies furnished by the eye are not full likenesses of bodies. They present an element of a body (surfaces), not the body itself (solidity).(212) Relative to colour, they are a cause of deception because they make non-existent surfaces appear as coloured, and thus are commonly called images, as I have said.

950. Although the surface of bodies is not the full likeness of the bodies themselves, it is more than a purely arbitrary sign, as I said. It contains a vestige and even a true but partial likeness of external bodies 1. in the perception of a corporeal force (the first element of body); 2. in the proportional extension (the second element of body); 3. in the shape similar to the surface of external bodies; and 4. in other tactile qualities, such as hardness, roughness, smoothness, softness, etc., which are the effect of the force distributed differently in the extension.
Furthermore, a very close bond between similar species and the external body is given by nature and formed by the continuous rays of light, which I have already explained.

951. Aristotle erred when he made sensible species, which are proper only to the sense of sight, the same for all the senses.(213)
Reid denied all sensible species and fell into the opposite error. Aristotle made what is proper to sight alone common to all the senses: bodies were known through species. Reid made what is proper to touch alone common to all the senses: bodies are perceived directly, without species or likenesses.

952. Reid removed all sensible species from the perception of bodies and in their place analysed the way we arrive at the sensible knowledge of bodies. The apparent result was his distinction between sensation and perception. Although I have already dealt with this distinction of Reid's, I will examine it more closely. He describes it in the following passage:

When I smell a rose, there is in this operation both sensation and perception. The agreeable odour I feel, considered by itself, without relation to any external object, is merely a sensation. It affects the mind in a certain way and this affection of the mind may be conceived, without a thought of the rose, or any other object. This sensation can be nothing else than it is meant to be. Its very essence consists in being felt; and when it is not felt, it is not... It is for this reason that we before observed that, in sensation, there is no object distinct from that act of the mind by which it is felt.(214)

He also tells us that whenever he considers sensation in this way, that is, separately from perception of the external object, he considers it abstractly.(215)
This way of speaking could make us believe that sensation is not really separate from Reid's perception. In abstraction, we mentally separate in some way things which cannot be thought as separate without contradiction [App., no. 39].

But this is not the case. According to Reid, the power governing perception, a mysterious potency totally different from sensitivity, differs from the potency governing sensation. It is a kind of natural suggestion (as he calls it when describing perception) which posits the existence of the external object we sense. It seems certain therefore that he is speaking of a real distinction between sensation and perception.

953. Galluppi noted a defect in Reid's distinction. If it were true, as Reid thought, that we perceive bodies with a potency different from that by which we receive sensations and without any knowable bond with sensation, scepticism about our cognitions of bodies would be inevitable. If, when we receive sensations, a law of nature forced upon us the persuasion of the existence of bodies without any other reason, the persuasion would be blind. This unique, arbitrary belief would be a pure fact justified by nothing.
Galluppi therefore rejected Reid's real distinction between sensation and perception, regarding it as a pure abstraction.(216) For him, the perception of bodies was included in sensation. He granted the direct connection of our spirit with external bodies but considered this connection essential, not arbitrary, as Reid claimed.
In Galluppi's system the objective and subjective elements are, in his own words, two relatives forming one single thing in sensation:

The object of perception is a necessary condition for perception. The objects of our primal perceptions are concrete things, that is, modified subjects. Every sensation is by its nature the perception of an external subject. The connection between sensation and an external object is not that of causality; it is also the essential connection of perception and its object. Moreover, this connection is not that between a representation and the thing represented. According to me therefore sensation is intuition(217) of the object.'(218)

954. Although Reid affirmed the direct communication of our spirit with external bodies,(219) he found it inexplicable.
Galluppi, who made a better analysis of sensation, found that the perception of bodies was already contained in sensation. This was his solution to Reid's difficulty concerning the connection or communication between sensation and the perception of bodies.
My analysis of sensation shows that if Reid had exaggerated the separation between perception of bodies and sensation, Galluppi had exaggerated their union by maintaining that the perception of an external body was included in the intimate nature itself of sensation.

955. It is true that a close bond exists between sensation and the perception of an external body. But the connection does not come from the nature of sensation or from feeling in general; it comes from the special nature of acquired sensations.
We have shown that the fundamental feeling(220) exists before all acquired sensations. The soul is united to the body by means of a wonderful bond, an intermingling, so to speak, called life, and it diffuses the feeling of life into the extension of the whole sensitive body, called its matter. Because an external sensation is a modification of this first feeling and cannot be thought without it, the contrary claim that myself and its animal feeling depend for their existence upon an external sensation, is not true.

956. We can now indicate how, and with what limitations, external sensations are joined to the perception of bodies.
Touch gives an immediate communication with external bodies. The four senses of sight, hearing, smell and taste, in so far as they are touch, give an immediate communication with their own stimuli, that is, with the minute particles affecting them. The sense of sight (and proportionately the other three senses, as we have explained) indicates distant bodies that do not touch it. It has no immediate communication with them but makes them known by means of signs or sensible species.

957. We cannot say that the senses, even as touch and proffering an immediate communication with bodies, fully perceive bodies themselves. They perceive only certain corporeal elements, two of which are force and surface extension.(221) To complete the perception of a body, solidity or extension in three dimensions must be added, or at least the possibility or expectation of finding new tangible surfaces, according to a fixed law. Touch itself, joined to movement, discovers and perceives new surfaces within the given space and thus an expectation arises in us of being able to discover new surfaces according to the same law. In this way the sense perception of external bodies is completed.

958. Of itself, therefore, the sensation of touch does not give a full, complete perception of bodies. It perceives some corporeal elements and should more correctly be called, as we have said, corporeal perception rather than perception of bodies. But it is completed through an association of many touch-sensations.

959. In this sense, it would not be out of place to say that we perceive bodies by means of certain traces or impressions that they leave in us as the inchoate perception we have of bodies.

960. Although this corporeal perception comes immediately from bodies, it is nevertheless in us, in our sensation, an effect of bodies upon us. Because our sensation is characterised by a passivity which extends to the whole surface encompassed by the immediate sensation, it makes us aware of this passivity, that is, indicates something outside us. To be aware of the surface in which the passivity is diffused is to be aware that whatever is outside us is extended. In fact, as long as we are thinking of the external body acting on us, its extension and that of our sensation are identical; thus there is an immediate communication between the body and us. But once the body has been removed (even by abstraction), it is the extension of the sensation that gives us the extension of the body. Considered separately, then, the sensation becomes a likeness of the body because it has an equal extension. In this sense we can say that we know bodies by means of likenesses that they leave in our senses or in our imagination. This proposition can thus be reconciled with that which says we communicate immediately with the external world through the senses, although it is dangerous to use it without some kind of explanation.

(207) By means of writing, human ingenuity indicates all human thoughts through sensations of sight and in this way gives hearing to the deaf, so to speak, and speech to the dumb.

(208) Sometimes it provides us with a sensation that we notice and distinguish more easily than touch. Touching a delicate rose petal can give us such a weak sensation that we do not distinguish it from the feeling in our fingers, although our eye notices the petal straightaway.

(209) Éléments de la Philosophie de l'Esprit humain, c. 1, sect. 1.

(210) Because metaphysical expressions taken from the sense of sight and applied to the other senses are used universally, the difficulty of guarding against this common vice of philosophical language is so great that I would be afraid of asserting that I myself have not sometimes made similar inexact statements. I will simply note an expression of Galluppi who was certainly not ignorant of the danger and falsity of expressions taken from sight and applied to the action of the other senses. He calls 'intuition' the perception of bodies carried out equally by all the senses (Critica della conoscenza etc., vol. 2, §71). The use of the word 'intuition' to explain the immediate perception of bodies by all our senses seems just as inappropriate as saying that our eye perceives bodies by means of rays of light.

(211) I say 'five senses' because the first perception of a body is made with our fundamental feeling. This perception is not only immediate but makes us perceive corporeal nature at a deeper level than any other perception, as I have explained.

(212) The perception of bodies by sight is always completed by habitual judgments or associations of ideas. When I see a portrait, I see only a surface, but this surface not only recalls the surface of the person in the portrait; I also seem to see the person herself alive and complete. I immediately recall in the likeness the full idea of the person; I seem to be talking with her here and now. All the solidity, as it were, of the person (body, soul, learning, habits, virtues) is recalled by a single act. I inadvertently add everything, as soon as I see the outline, with which I have always associated many ideas. These associations accompany the use of touch as well as use of the eye, because a single touch often makes me think of the whole of a solid together with the qualities I know it has.

(213) The impropriety of applying the words 'sensible species' to the different sensations of sight seems to me inexcusable. However if the impropriety is removed, the two apparently contradictory propositions, 'Touch perceives bodies directly' and 'We perceive bodies by touch through likenesses' can be true. The first is true in the sense that bodies act directly on our organs. We therefore perceive their direct action, which is the essence through which we know them (bodies are known only through their action). Hence we perceive directly the essence we call body. The second is true in the following sense: the action of external bodies is a modification of our own body. This modification gives a sensation which terminates in an extension. In this extended sensation we perceive the external body in its likeness. These two ways of speaking, which can be used in a discussion on touchperception, is founded on the double nature (subjective-extrasubjective) of sensation, which I have already explained. The double nature does not exclude a constant, necessary union between the two elements which give rise to sensation. However, although both propositions have their truth, the second could not be applied to the perception we have of our body through the fundamental feeling. This feeling is not known to us by any kind of likeness, although it can make itself a likeness of external bodies in the way I have explained.

(214) Essay on the Powers of the Human Mind, etc., Essay 2, c. 14.

(215) Recherches sur l'Entendement humain, etc., c. 2, sect. 1.

(216) He says: 'In sensation, our act of consciousness distinguishes the internal modification from the subject felt as something outside us. Many subjects outside us are therefore objective. Consciousness isolates and distinguishes these from what is subjective, but does not isolate the modifications of external realities from sensation. This gives rise to appearances' (Saggio filosofico sulla critica della Conoscenza, vol. 2, c. 6, §114).

(217) Cf. intuition in footnote 210.

(218) Saggio filosofico sulla critica della Coscienza [Conoscenza], vol. 2, §71.

(219) A serious defect of Reid is his failure to see in what this direct communication consists. I said it was in sensations, but he talks about intellective acts which apprehend bodies directly. Not even Galluppi is entirely free from this error, an error which reveals his sensism.

(220) It might be asked whether myself, considered alone, contains passivity, and therefore perception. The answer to this question would necessitate analysis of myself, which is outside the purpose of this work. If, however, such an analysis were to reveal passivity and perception, it would not concern the perception of external bodies we are discussing. The present argument does not seek to establish generally 'that sensation can be deprived of all perception', but 'that sensation or feeling can exist without the perception of external bodies'.

(221) The fundamental feeling of our body is the only way we feel a solid body completely, that is, our own; in itself, no external sensation does the same.