CHAPTER 15

The relationship between intellective and
sense perceptions of bodies

961. I know of no modern philosopher who has not confused, at least occasionally, sense perception and intellective perception. This leads me to believe that it is very difficult to grasp the distinction, and that it would be helpful to focus carefully upon it. I shall attempt this in the present chapter and take the opportunity also of indicating the useless disputes generated by the confusion and eliminated when the confusion is removed.

962. First, we must pay careful attention to the fact that the term of feeling is always something particular. With this principle in mind, we can discover the properties of both sense perception and intellective perception, since one of the consequences of the principle is: 'Whatever is universal in the perception of bodies, must be attributed to the intellect, not to feeling.'(222)
When I mentally perceive a body, that is, when I judge that an object having the nature of body exists, I have an intellective perception of body. But I could not think it like this unless I had the universal notion of existence.

963. What is involved in sense perception? With the fundamental feeling we feel our body as something that is one with us. This perception, although complete, is difficult to observe and analyse. So let us turn to touch, which is the second way by which we attain sense perception of bodies. The sensation of touch, in itself subjective, is also corporeal perception: 1. in so far as it is a term of the action of something outside us and 2. presents this term as an extended surface.
Repeated, varying sensations of touch, promptly helped by those of sight, unite to give our sensitivity the expectation of finding, by the use of movement and force, new surfaces under any perceived surface. Sense is also subject to this law of the instinctive expectation of similar feelings, as experience shows us. It is due to a habit or inclination formed in sense, a kind of instinct to repeat acts similar to those that have been done many times and expect similar results. This instinctive expectation of new corporeal surfaces, after the first surface has been removed, perfects sense perception.

964. Let us now see what the understanding does to complete its perception of bodies. When, through the senses, our spirit has received the corporeal elements so far described, the understanding completes the perception in the following way.
The experience we undergo in a sensation has two aspects: from the point of view of its term, ourselves, it is experience; from the point of view of its origin, it is action. Action and experience indicate the same thing under two different, opposite aspects. Sense perceives what we are talking about simply as experience and the expectation of new experiences; only the understanding is able to perceive it as action, while adding nothing to it. The understanding considers the thing absolutely; sense perceives it in a particular respect, that is, relatively. Understanding originates in us, particular entia, but directs its attention to things in themselves; sense never moves from the particular subject, ourselves, to which it belongs.

It is, therefore, the work of the understanding to conceive the action of something 'other'. But to conceive an action means to conceive a principle in act. Thus, when the intellect perceives an action, it always perceives an agent as such, that is, an ens in act. But it does this by means of the idea of being that it possesses. When it perceives the agent as an ens different from ourselves and endowed with extension, it has perception of bodies.
We see that to perceive a body the understanding does nothing more than consider what the senses present. But it does not do this relatively to ourselves as sense does; setting us aside and ignoring us, it adds the universal concept of being. The intellective perception of bodies is, therefore, the union between the intuition of an ens (agent) and sense-perception (experience); it is a judgment, a primal synthesis.

965. But if we set aside the judgment about the actual presence of bodies, we are left with their simple possibility. This is their pure idea or simple apprehension.

966. When Locke says that the soul receives simple ideas passively from the impressions of external things,(223) he is confusing both sense perception and sensation with ideas.
The whole of antiquity had recognised the truth that passive sensations are not ideas, and that some activity of the understanding is required if ideas are to be acquired from sensations [App., no. 40].

967. Eventually Locke's error was seen. Thinkers recognised the necessity of some action of our understanding on sensations if we were to have ideas. But modern philosophers are divided in their opinions on the nature of this intellective operation.
Laromiguière recognised the necessity of an intellective operation. According to him, ideas are produced by the understanding's meditation on sensations. This was a step forward, but his meditation needed to be defined. He reduced it to a simple analysis, defining idea as 'a distinct feeling, a feeling resulting from other feelings'(224)

Galluppi also held that ideas are a product of meditation on feelings but thought that Laromiguière, by restricting meditation to analysis, had not defined it accurately enough. He pointed out that analysis could not form ideas of relationship because, as Laromiguière himself agreed, these ideas demand a comparison and hence a synthesis. Nor do they have any external reality from which the feeling of the ideas could come. Galluppi added synthesis to Laromiguière's analysis. He says:

968. This was another step forward by the new philosophy, but I do not think that Galluppi carefully examined the conditions required for intellective analysis and synthesis. This omission prevented him from finding the truth.

I have pointed out that reflection or meditation, synthesis or analysis which adds nothing to feelings, can never produce an idea. They never get beyond feelings themselves in which they end and rest and by which they are individualised. The intellective operation necessary for forming ideas must therefore add to feelings the universality feelings lack. Attention which adds nothing to feelings ends in them, and does not produce anything further. Adding universality to a feeling means simply seeing it with a universal view, that is, seeing it not only in its individual entity but even before that in its possible entity. If we consider a feeling not in so far as we experience it here and now but in so far as it is and could be anywhere, we are considering it outside its actual perception and in its essence, that is, in its idea. Meditation which forms ideas from feelings must therefore be an intellective activity which can consider things not as actually existent but in themselves and as possible to exist in any place whatsoever. This activity or abstraction, a species of analysis, presupposes the idea of thing in all its universality; it presupposes antecedent thought through which we know 'that every feeling or sense perception, every felt thing has essence or possible existence in addition to individual existence.' In short, possible being present to the mind is the condition without which the understanding's meditation on its feelings cannot be conceived as apt to produce ideas.

The same conclusion results when we take particular note of what synthesis requires. I have shown how the comparison of two or more things needs a preceding idea to which the two things may be compared. Synthesis therefore presupposes universal ideas already formed in us (cf. vol. 1, 180-187). If Galluppi had asked himself, 'What conditions are necessary if the intellective meditation on feelings that forms ideas is to appear possible?', he might have seen with his usual insight that a previous universal idea is required for this meditation. If he had seen this, he would not have denied every primal, innate idea in human understanding, nor have attributed the cause of ideas to some inexplicable, inept and indeterminate intellectual activity; he would thus have escaped being numbered among the sensists.

969. Reid recognised better than others the nature of the internal activity of the spirit through which, on the occasion of sensations, ideas are formed.
He could see that Locke contradicted himself by saying that sensitivity is a purely passive power and, in the case of the source of ideas, by associating a judgment with it, unaware that judgment, according to his own teaching, must be an operation posterior to ideas, not prior to them or their cause.

Reid distinguished perception from sensation: sensation was passive and furnished no ideas at all; perception on the other hand was active and consisted in a natural, spontaneous judgment through which persuasion of the existence of external bodies was acquired.
He claimed that sensation was in no way similar to perception but was always united to it, that is, perception followed immediately upon sensation by means of an inexplicable law of nature. As a result of this proximity, judgment was attributed to sense in everyday speech (which he praised and defended).(226) He says:

I cannot pretend to assign the reason why a word, which is no term of art, which is familiar to common conversation, should have so different a meaning in philosophical writings.(227) I shall only observe, that the philosophical meaning corresponds perfectly with the account which Mr. Locke and other modern philosophers give of judgment. For, if the sole province of the senses, external and internal, be to furnish the mind with the ideas about which we judge and reason, it seems to be a natural consequence, that the sole province of judgment should be to compare these ideas and to perceive their necessary relations.
These two opinions seem to be so connected, that one may have been the cause of the other. I apprehend, however, that, if both be true, there is no room left for any knowledge of judgment, either of the real existences of contingent things, or of their contingent relations.(228)

970. Granted this observation and the discovery of the necessity of judgment for forming ideas, Reid should have investigated the conditions necessary for making judgment possible. An analysis of judgment would have shown the absolute necessity of a pre-existent universal idea.
But he lacked either the courage or the energy to take this step, or possibly he drew back because of the horror (drawn from the education of his time) of the smallest intellective element connatural to the human being, to which the analysis would have inevitably led him. He was content to say that the judgment was made through some unknown law of human nature itself.

Galluppi considered this language very vague: the perception of bodies could not be something totally different from sensation. He meditated on the relationship between sensation and perception in order to re-unite them, if possible. He concluded that every sensation by its nature was a perception and that the essence of perception consisted in perceiving something, that is, in having an object. Hence, he ended by confusing what Reid had so strenuously tried to distinguish.
But careful investigation will show that the difference of opinion between these two men arose from their failure to distinguish between sense perception and intellective perception.
Reid was aware of intellective perception, and saw that it had to be something entirely different from sensation. It required a judgment, an essentially active faculty; sense however considered in itself is a passive power.

Galluppi concentrated on sense perception and saw that it was joined to sensation - it was in sensation itself. He therefore denied Reid's separation of sensation from perception. Because he went no further than this kind of perception, Galluppi was unable to calculate the full measure of intellectual activity necessary for the formation of ideas. He certainly saw that ideas were formed by the understanding's meditation on feelings. He also knew, better than Laromiguière, the nature of this meditation which Laromiguière limited to analysis. Galluppi proved the necessity of a synthesis, but stopped there.

If Galluppi had continued and analysed the synthesis, he would have discovered that it could not take place without a judgment. He would have known therefore, like Reid, all the force of the intellectual activity necessary for the generation of ideas. And after discovering the need for a primal judgment, it would have been easy for him to recognise the necessity of a universal idea antecedent to the judgment. In this way, he would have discovered both the nature of the intellective perception of bodies and the sole source of this perception.

971. The natural steps taken by philosophy to discover the idea of being present naturally to the human spirit are therefore (in the order of theories, not of time):

1. First, sensations are considered substantially the same as ideas (Locke).

2. Next, meditation on sensations is recognised as necessary for ideas.

3. This meditation is analysed and is thought to consist in pure analysis (Laromiguière).

4. Meditation is investigated more deeply and is seen to require synthesis (Galluppi).

5. But synthesis cannot be made without a judgment. This meditation of the understanding must therefore be an act of the faculty of judgment (Reid).

6. Analysis of this faculty of judgment shows the necessity of previous universal ideas.

7. Universal ideas are classified and their connection investigated, resulting in a series of universal ideas, some of which cover a wider sphere than others. Narrower ideas are seen to be deduced from more extensive ideas.

8. Finally, the most universal idea cannot be deduced from any other, because there cannot be a more universal idea above it. It is the primal idea, and with its discovery we can now see the possibility of the judgments necessary for the formation of all other ideas.

972. I have shown that Reid was aware of the distinction between sensation and the intellective perception of bodies but failed to consider the middle term, sense perception. Consequently he found the two terms so far apart that, although he united them in time, he separated them totally in nature.

However, in several places we can see that he did not have a clear and distinct concept of intellective perception and of the idea of bodies. The blame lies with the prejudices of the education given at the time: it held in contempt any claim that there can be something outside the limits of acquired sensation.(229)

973. We can see this particularly where he refers to Aristotle's teaching and confuses the latter's sensible species with ideas. Sensible species have nothing to do with ideas. When I have a sensation in my eye, I have a sensible species of the distant body. This body which I perceive by means of the sensation has not touched me; I am touched only by the light emitting from the body. The species is obviously different from the touchable body to which through habit I refer it.

The visual species of a body differs totally from the idea I have of a perceived body.
The idea is essentially universal; the species is essentially particular.
In the idea I find the definition of body; the visual species is simply a sign of it.

To have both the idea and the intellective perception of a body, I must judge that 1. an ens exists; 2. this ens has modified me and acted on me in a way determined by its extension and other sensible qualities. To make these judgments, I must 1. perceive the sensible qualities; 2. perceive, by means of touch and locomotive force, the felt term in its action (sense perception); and 3. form the act of judgment about this felt term, by which I come to see it as sharing in existence. In short, I intellectively perceive the body as one among possible entia, limited in a determinate way by my senses.

Now I need none of this in order to have the sensible visual species: I need neither intellect (faculty of the intuition of being in all its universality) nor judgment (faculty of applying the idea of being in all its universality to particular things perceived by sense) nor even sense perception. All I need is my sight, which is common also to brute animals, without asociating with it any other sensation, operation or information.

974. Reid's error may have been caused by Aristotle's metaphorical expressions. Aristotle describes sensible species, phantasms and intelligible species or ideas as substantially the same thing, as if they were little images or statuettes which are gradually purified and spiritualised as they pass through the three powers of sense, phantasy and intellect, just as liquid or dust is refined as it passes through filters of varying density.(230)

975. Reid classed all these internal experiences under one general heading as something in between things and us, and by attacking them all, brought ruin to ideas as well as to sensible species and phantasms.
Consequently he speaks about Plato's ideas in the same way as he does about Aristotle's sensible species, as if the same arguments could be used about both, and both could be eliminated by the same reasoning. But this is impossible [App., no. 41].

976. According to Descartes, the existence of bodies is made known to us through the principle of cause. This was the opinion of a great number of philosophers after Descartes and also (this is not a joke!) of Destutt-Tracy.
Galluppi denied that we know bodies through the principle of cause. He argued clearly and convincingly against Tracy: 'If the principle of causality makes us know objects, it cannot come from objects.'(231) Tracy had no reply to this observation, but my reply is: certainly the principle of cause cannot come from real things; it comes from the idea of being.

977. All Galluppi's other arguments against the principle of cause relative to the knowledge of the existence of external bodies are reduced to the following: 'If sense does not put us in direct communication with external objects, the principle of cause can only create an external world a priori. Idealism is therefore inevitable.'
This argument shows that while he was very concerned about the necessity of sense perception, he neglected to observe intellective perception.

978. I grant Galluppi an immediate communication of our spirit with the external world, but this implies the necessity of sense perception. Otherwise there would be no matter to which the principle of cause could be applied. If the principle is to act or produce anything, it must be applied to something. Apart from all this, there is still no intellective perception in which alone the knowledge of bodies consists.
Sense perception of bodies is direct;(232) it is a fact and needs no principle of the mind to form it. If we analyse the fact, we can easily distinguish in it, as Galluppi himself does, the act of perception and its object, and the intimate, necessary connection between these two - note, object here is understood as term, because sense itself has no real object.
The intellective perception of bodies is however a judgment. This judgment needs an intellective principle, or at least an idea, a universal which takes the form of principle when reduced to a proposition. This universal idea which makes us perceive bodies intellectively is the idea of existence, as I have explained throughout this work.

979. Because philosophers confused external sense perception with intellective perception, they made a single fact out of the two.
The same confusion and suppression of an element occurred in the case of internal sensitivity or the perception of one's own feeling. I pointed this out when discussing Malebranche (cf. 439).
To clarify the matter further, I will deal with the confusion present at the very beginning of Descartes' doctrine.

'I think, therefore I exist'; this is the foundation stone of Descartes' structure. But there is an easily recognisable and insoluble objection to this principle, an objection that was naturally and quickly raised: If you say, 'I think, therefore I exist', you must presuppose the knowledge that what thinks must exist. In the very first line and at the start of your philosophy you take for granted the notion of existence, which needs to be explained.

980. If the objection had been calmly accepted and if the path it indicated had been followed by people searching for the truth, they would have been led directly to the beginning of all philosophy, the idea of existence.
But Descartes paid no attention to the objection. Instead he maintained that the first words of his philosophy, 'I think, therefore I exist', were meant to point to a truth directly perceived, not to something discovered by reasoning.(233) He did not realise that the word 'therefore' gave the lie to his reply.

The great man was quite capable of seeing the force of the objection, but could not bring himself to abandon the true part of his thought. What is needed is the distinction between the perception of myself as feeling and the intellective perception of this same myself. The former is direct and simple, given by nature; the latter is also direct but not simple because it presupposes a universal idea, the idea of existence. Failing to make this distinction, Descartes attributed to intellective perception what was proper solely to feeling. Both he and his opponents were half right; none of them was fully right.

981. If we note the language he uses (because language is the portrait of ideas), we can see that he was speaking about intellective perception and attributed to it what pertained only to feeling. He says, 'I think, therefore I exist.' Surely there is some reasoning in these words? Surely the word 'therefore' expresses a consequence? 'Thinking' is certainly not the same as 'existing'. Thinking is the attribute, the predicate of an ens. And an ens cannot be intellectively conceived unless we know what being is in all its universality. In fact, the whole of the long first Meditation, in which the phrase 'I think, therefore I exist' occurs, is an example of continuous reasoning.

982. Discussing this principle, Galluppi says that Descartes' reasoning simply means 'that our existence is of such a kind that it is confirmed whether we deny it or doubt it'.(234) This is true, but knowing that our existence is confirmed by our denying or doubting it is itself an example of true reasoning, an indication that the act of denial and doubt is connected with existence. But this judgment or synthesis cannot be made, unless we know existence separately from the act of denial or doubt. If we perceived only denial and doubt, we could not carry out any mental act. In a simple perception where everything is individual, we cannot make distinctions and analyses without the help of some universal notion [App., no. 42].

(222) This truth was known and affirmed by the whole of antiquity. Thirteen centuries ago, Boethius correctly stated: Universale est dum intelligitur, singulare dum sentitur [What is understood is universal; what is felt is particular] (Sup. Porphir. Proem. In Praedic.). This was a repetition of Aristotle's opinion nine centuries earlier.

(223) 'We have hitherto considered those ideas, in the reception whereof the mind is only passive, which are those simple ones received from sensation and reflection before mentioned, whereof the mind cannot make one to itself, nor have any idea which does not wholly consist of them' (bk. 2, c. 1).

(224) Vol. 2, c. 1.

(225) Saggio filosofico sulla critica della Conoscenza, vol. 3, c. 1.

(226) Nevertheless, according to his principles, Reid should have recognised a common error in this mode of speech when it says 'Sense judges', and thus confuses sensation with perception. Reid had in fact made great efforts to distinguish the two and affirmed in many places that perception did not in any way resemble sensation; the two facts depended on principles which observation could not reduce to unity in any way. But the example he gives of ordinary speech attributes the two operations of feeling and perception (judgment) to a single power, sense. In the other words, the evidence he adduces in favour of his opinion is ranged entirely against him. Indeed, it is often very difficult to know what the mass of people think, to know whether they think correctly, and even whether they have an opinion about certain matters!

(227) According to Reid, philosophers use the word 'sense' to mean 'a power that gives ideas without judgments', but ordinary people use it to mean 'a power which gives us ideas together with a judgment'. His observation indicates that the fundamental proposition of the whole of this work is confirmed by the authority of the human race whose manner of speaking shows mankind's belief that 'a judgment by the mind is necessary for forming ideas'.

(228) Essays on the Powers of the Human Mind, etc., vol. 2, p. 76.

(229) The degree of confusion among minds after Locke's time and the loss of the distinction between sensation and idea can be seen in the way 'idealist' is generally applied to Berkeley, Hume and their followers. These authors wanted to reduce all human cognitions to sensation alone. They supported their systems with the following argument: 'If sensations are in us, the external world is in us.' Thus, because they called sensations ideas, they called themselves idealists, a name used by everyone. But their correct name should have been simply sensists. This observation removes any wonder that may arise from seeing how close idealists and materialists are. All wonder ceases if we bear in mind that the title 'idealists' was incorrectly given them and means simply 'sensists', because the gap between sensists and materialists is clearly not great. However, the wonder universally experienced when philosophers called 'idealists' are seen to associate so easily with 'materialists' is an involuntary witness to the consciousness of the human race. This witness shows that the human race is definitely aware of the difference between idea and sensation, even if philosophers have lost it.

(230) Essays on the Powers of the Human Mind, Essay 1, c. 1. - Stewart, a disciple of Reid, repeats the same error in Éléments de la philosophie de l'Esprit humain, c. 1, sect. 1.

(231) Saggio filosofico sulla critica della Conoscenza, bk. 2, c. 1.

(232) Intellective perception can also be said to be direct, in the sense that it is done through a first judgment.

(233) Cf. his reply to Second Objections.

(234) Saggio filosofico, etc.