Chapter 2

Origin Of Our Idea Of Corporeal Substance

672. Having shown that the feeling subject (the spirit, 'myself') cannot be what is understood in the word 'body' we must now see if what we mean by 'body' really exists, or indicates an imaginary concept without content. Our aim is to discover if there is such a thing as corporeal substance, as common sense affirms, and if so how we attain our idea of it.

When we have found the way in which we form our idea of body and persuade ourselves, as we form this idea, that bodies really exist, we shall also have demonstrated the existence of bodies. Such a demonstration, taking its origin from the persuasion of the existence of bodies, is valid provided that reasoning, dependent upon perception for its first link, is capable of finding or proving the truth. Most people do, in fact, take the existence of bodies as the most certain of all things, but modern sceptics have tried to throw doubt upon ordinary reasoning. In the next section of the work, we shall refute the objections against the validity of reasoning, and thus reinforce what we intend to say here about the existence of bodies.

673. We have said that the concept underlying the word 'body' is that of 'a proximate cause of our sensations' and that 'this cause is the subject of feelable qualities' (cf. 667). We have to show, therefore, how we obtain a reasonable persuasion of the existence of 'a cause of our sensations different from ourselves', and that this cause is 'the subject of feelable qualities'(1). This will not be difficult if we remember what we have said.

674. Sensations presuppose a cause different from ourselves. External sensations are facts towards which we are passive (cf. 661-666). Passive facts are actions done in us of which we are not the cause (ibid.). Such actions suppose a cause different from ourselves because of the principle of cause (cf. 567-569). Consequently, sensations suppose a cause different from us. And this was what we had to show.

675. We have seen that sensations suppose a cause different from ourselves (cf. 674). It was shown that a cause is always a substance (cf. 620 ss.). The cause of our sensations, therefore, is a substance.

676. Because our sensations are actions done in us of which we are not the cause (cf. 662-666), we experience energy capable of changing us. This energy is a substance working upon us and we call it 'body'. The action of a body upon us is, therefore, the effect not of any particular power of the body, but of the body itself. In our definition of body, we do in fact call it that which modifies us in this way. Moreover, we recognise no other coordinated powers in the agent indicated by the word 'body'.
But the action of an operating substance is always intimately joined to the substance itself, because the force or energy of a being is inseparable and indivisible from the being itself. The substance which causes our sensations is therefore joined to them immediately.

677. The energy or force which we experience as producing our sensations is limited because its action within us, of which we are not the cause, is limited. But this is the energy which gives us the idea of substance or, as we could say in equivalent terms, we perceive in that energy or force a being, the cause of our sensations, which is distinct from ourselves. But the being in which we mentally conceive this energy is as limited as the energy we experience because this being is for us only the energy itself considered as existing. Hence the being we think of as the substance and proximate cause of our sensations is limited.

678. This proposition is evident. We cannot name anything unless we know it and according to the way in which we know it. Hence we cannot name it except in so far as we know it.

679. Words express beings in so far as we know them intellectually. The meaning of words is limited, therefore, by our knowledge. It is an abuse of language, leading to equivocation and sophisms in our reasoning, to use a word with a wider sense than the concept of the being it names; we are using it for what it could mean, although we have no idea or perception of what this may be. Words used like this have neither the meaning nor the purpose given them by the human race.

680. Defining a body is equivalent to stating the use made of the word 'body'. If we wish to define this word, therefore, we can do it either by analysing all the ideas which form its meaning, or by indicating some characteristic idea, wholly proper to the being under review, which will lead us to the being named by the word in question. For the present, we need to clarify the word 'body' only in the second way. Later on, we shall define it more fully and closely.

We have seen that we form the idea of body from that which acts in us, that is, from the force or energy we experience in sensation (cf. 640-643). Because this energy is limited, we can draw from it only the concept of a limited being (cf. 677). All our knowledge of bodies is therefore that of limited beings. But words express beings in the way in which we perceive and know beings (cf. 678). The word 'body' was therefore invented to signify a limited being. Using it in some other sense would be to abuse it (cf. 679).

681. Bodies are the proximate cause of our sensations (cf. 667). Bodies are limited beings (cf. 680). God is not a limited being. Therefore God is not the proximate cause of our sensations.

682. The proximate cause of our sensations is an existing substance. This substance is called 'body'; it is not God (cf. 681). Hence bodies exist, and they cannot be confused with God.

684. [...] The demonstration may be expressed and summed up in the following propositions.

1. Everything that occurs in our feeling is a fact.

2. In sensations and corporeal feelings (corporeal is used to determine the feelings, and may be taken here as an arbitrary sign). we experience in our feeling an action of which we are not the cause; we experience an energy, a force different from ourselves, at work in us.

3. This energy, or felt force, conceived intellectually, is the idea of a being. Our understanding, through the necessary principle of substance (cf. 583 ss.), conceives this energy as really existing.

4. Such energy is real and limited; consequently, because the conceived being is only the same energy considered in the existence it possesses, and as such formed and limited in our conception, it too is real and limited.

5. This limited being, which we call 'body' is not the sentient subject ('myself'), nor can it in any way be God, whose idea embraces that of an infinite being.

6. Body, therefore, a limited substance and proximate cause of our sensations, exists.

As far as I can see, all these propositions are irrefutable and form part of human common sense. [...]

687. In order to know if corporeal substances exist, we must first recall the definition of substance. As we have said, substance is 'Something capable of being conceived intellectually in our first mental conception'(2). Note that the definition contains the following implications.

1. In order that something be a substance, it does not have to exist independently of every other thing. If that were the case, there would be no created substances because they exist only in dependence on the first cause. For something to be worthy of the name 'substance', it is sufficient for us to be able to conceive it by itself, separate from its first cause. Although it cannot exist totally of itself, it has its own proper existence which enables it to be thought by us in isolation from everything else; its first concept contains no extraneous element.

2. Consequently, a thing can be called 'substance' even if we have to rely on knowledge of something else, such as its cause. in reasoning to its existence or in understanding it completely. As we have said, although nothing can be understood without knowledge of its ultimate cause, this does not prevent us from calling it substance. A first mental conception can be formed of the thing without need of anything beyond it; it can be seen of itself in our first intuition and thought. In a word, its first concept is independent of every other concept; it presents itself as an incommunicable essence, mentally distinct from other essences.

We have already noted that if we give to the word 'substance' a more extensive meaning than that granted by common usage, we open the way to false reasoning and countless errors.

688. Bodies, therefore, are substances from the moment they can be conceived by us in our first mental conception as separate and isolated beings that cannot be confused with our spirit, with God or with anything else. Accidents, on the other hand, are such that they cannot be conceived as isolated in our first intellectual conception, but only in dependence upon some other being in which they exist or to which they belong. This is not the case with bodies whose perception, as we have seen, terminates in them without need of anything further (cf. 515-516).

689. [... We have distinguished] two elements in sensation: 1. the force acting in us (relative to which we are passive), common to all species of sensation; 2. the various terms and effects of this force, that is, the various sensations. We experience both the force and its different effects, but while we feel the former equally in all sensations, the effects are felt differently according to the variety of means and bodily organs in and through which the force acts upon us. But if the variety of terms and effects of this force (the sensations in so far as they vary amongst themselves) cannot be conceived mentally without the force that produces them, this in its turn cannot be thought without the being which operates (through the principle of cognition) (cf. 536, 483-485). Thus we arrive at substance, at that which constitutes a being.

690. We can now sum up all that we have said about the origin of our ideas of bodies.

I have within me, therefore, all the faculties necessary to explain the origin of the perception and idea of body. I have: 1. the faculty that continually beholds being (intellect), the first element of the idea of body; 2. the faculty (a 'common sense') that perceives a force at work in me which is not myself, and which therefore forms the essence of body, the second element in the idea of body; 3. the five exterior sense-organs that perceive sensations, the third element in the idea of body; and finally, 4. the faculty of primitive synthesis, or judgment, with which I judge as subsistent what I think in the idea of body.

691. Having established the faculties enabling us to perceive the individual elements composing our intellectual perception of bodies, we now have to explain how we unite these elements.

First of all, our various sensations and the energy at work in us are bound together naturally in such a way that we have to make use of abstraction if we wish to have and to think this energy separate from its particular term, that is, from one or other of the sensations. Because energy is the sensation itself considered in its general concept of action done in us and not by us, it cannot be perceived without sensation. Sensation itself, taken whole and entire as it exists in our feeling, that is, as the feeling of a determined action, is what we have called elsewhere corporeal sense-perception.

We now unite corporeal sense-perception with the idea of being in general through the principle of cognition, which includes the principle of substance. We do this for the first time through the act with which we judge that a body subsists, that is, the intellective perception of body. This act may be described briefly as follows: we are intelligent; as such, we perceive all things as they are, as beings, when they act in us; the bodily force corresponding to the essence of bodies acts in us(3) so that we perceive it as subsisting; this is the perception of bodies.

We have given a general description of the formation of ideas of body. We still have to describe how we perceive our own and other bodies.

Notes

(1) As we have said, these definitions depend upon the meaning given to the word 'body' by common usage.

(2) This characteristic is relative to our mind, but founded in the nature of the thing. The other definition I have given regards the thing itself: 'Substance is that through which a being is what it is', or 'Substance is the abstract, specific essence of a being considered in relationship to its full, specific essence'.

(3) As a result, the feeling we experience of bodies is a substantial feelinf, an immediate action of bodies upon us, which allows us to use the word perception to describe the first knowledge we acquire of bodies.