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10 Descartes, Principles I.48-76 Having satisfied himself that whatever is very clearly and distinctly perceived contains no error, but being as yet uncertain whether anything other than himself (meaning his own mind), his own ideas, and God exist, Descartes proceeded over the remainder of Part I of the Principles to, as he had put it when stating the second rule of his method, “divide each of the difficulties I examined into as many parts as possible and as may be required in order to resolve them the better. What follows is a study of the relations between the ideas and principles Descartes found within himself, culminating in a distinction of substances into two kinds, mind and body (the latter considered as something that may possibly exist but that is not yet known for a fact to do so), and an assertion that sensible qualities are not qualities of bodies but are instead merely “sensations” experienced by minds. As presented in Principles I, this claim receives effectively no support. It merits close examination. Another feature of this superficially dry section of the Principles merits close examination. Descartes wanted his Principles to replace the textbooks of metaphysics and natural philosophy that were being used in the universities, and many of the notions introduced here (substance, attribute, mode, property, accident, quality, universal, species) were ones that had been and were being employed by the Scholastics in their rival work. Part of Descartes’s purpose was to appropriate this terminology and reinterpret it in a way consistent with the corpuscularian philosophy he meant to advocate. This would simultaneously help to make his project fit with what had gone before, by enabling him to present it in language familiar to those in the universities, and to correct what he considered to be the errors of the past philosophy, by imposing new meanings on the familiar terms. But for all his efforts, Descartes’s philosophy remained deeply suspect to the theologians in the French universities, particularly the Jesuits, whom he most wanted to win over to his side. A principal reason for this was that Descartes’s doctrines could not be readily made to fit with the Catholic position on a flashpoint of the dispute between Protestants and Catholics, the issue of transubstantiation. This section of the Principles takes a none too subtle stand on that issue, one that did not fit well with traditional Catholic doctrines. QUESTIONS ON THE
1. What is a
substance?
2. In what
sense are bodies and created minds substances?
3. What is
required in order to know a substance?
4. What is it
about thought and extension that makes the one the sole principal attribute
of mind and the other the sole principal attribute of body?
5. What sort
of “things” are duration, order, and number?
6. From what
do universals arise?
7. What is a
universal term?
8. Distinguish
between genus, species, differentia, property, and accident.
9. Distinguish
between real, modal, and conceptual distinction. 10.
When is the distinction between extension and
body conceptual and when is it modal? 11.
What have we taken for certain and indubitable
from early childhood? 12.
Where does the pain of a stubbed toe exist? 13.
When are pain and colour clearly and
distinctly perceived? 14.
Why are pain and colour not
clearly and distinctly perceived when judged to be real things
existing outside of the mind? 15.
What must our judgments of colour be like in
order to avoid error? 16.
Do infants see objects as coloured? 17.
What initially led us, as children, to suppose
that objects exist outside of us? 18.
What initially led us, as children, to
attribute our sensations to external objects? 19.
On what basis did we originally ascribe
reality to objects? 20.
Identify four main causes of error. NOTES ON THE In Principles I.48, Descartes divided the things we perceive into three main groups: objects or substances, affections of objects or substances, and eternal truths. He declared that he would not have much to say about eternal truths. These are what he had earlier called “common notions.” They are principles we all accept as self-evident, such as that the same thing cannot both be and not be, or that nothing has no properties. — At least, all of us who are mature and unprejudiced, and have followed the approved method of gaining knowledge accept these notions. (Descartes recognized that some “common notions” might not actually be held in common by everyone. But he considered the exceptions to be due to the fact that people have been blinded by preconceptions, which make it difficult for them to see the evidence of some common notions. This is a position that raises obvious difficulties. Given any two people who disagree about some common notion, how can we tell which is the one who is blinded by preconceptions? But I pass on without examining this any further.) Descartes had much more to say about substances and their “affections.” He divided substances into two main groups, intellectual or thinking substances, and material or extended substances (also called bodies or corporeal things), and he further divided the affections that substances can have into four groups. There are affections that are attributable to substances of all sorts, like duration, order, and number. Then there are affections that are specific to intellectual or thinking substances, like perception, volition, and all the various “modes” or ways in which perception and volition may be modified (sensing, imagining, conceiving, desiring); and affections that are specific to material or extended substances (all the ways in which extension can be modified). Finally, there are affections that don’t appear to belong to substances of either sort, at least not when they are taken alone, but that Descartes took to be special to those substances that are a kind of union of thought and extension. These include things like appetites, which are obviously things that are felt by minds but that involve doing things with or to bodies. They also include emotions, which are less obviously linked to bodies than to minds, but may be supposed to have something to do with body insofar as most emotions involve physical states the body and, like appetites, involve some reference to objects. Anger, for instance, is accompanied by heat in the body and is also directed at a particular body. But Descartes also included hardness, weight, colour, taste, smell and pain on the list, declaring that all of these qualities are “sensations” rather than qualities of bodies. He had more to say about this towards the end of Part I of the Principles. Before turning to that, however, he offered a number of comments on the other categories of being he had defined. Descartes’s ontology. Descartes considered a substance to be a thing that can exist on its own, apart from everything else. If only in virtue of the doctrine of constant creation, discussed in the lecture on Principles I.1-23, this entails that God is the only thing that would deserve to be considered a substance, since everything else depends on God for its continued existence. However, Descartes considered that the term, “substance,” could also be used in a derivative sense to refer to everything that is capable of existing apart from anything else other than God. What would those things be? Descartes maintained that we can answer this question by asking ourselves what things we can clearly and distinctly conceive of. If your clear and distinct conception of one thing does not include any thought of something else, then those two things should be capable of existing one apart from the other. The reason for this is that God, being all-powerful, can bring about any state of affairs in which there is no evident incoherence. Being able to clearly and distinctly conceive one thing apart from the other therefore constitutes evidence that, even if the two are as a matter of fact always encountered together in our experience, they are really distinct substances because the one could, in virtue of the power of God, be made to exist apart from the other. Among the things that satisfy this description are created minds, each of which can be conceived apart from any of the others and from any material thing, and each of the spatial parts of bodies, however far down we may consider them to be divided (recall Descartes’s cautions on the limits of our thought on this matter at Principles I.28), each of which may be considered apart from all the surrounding parts and from any created mind. Among the things that, it turns out, do not satisfy this description are time, space, number, and Platonic universals like “the good,” or “fox,” or “wood,” or “mercury.” Note that this is not (yet) to say that there actually are such things as other minds or bodies. The claim is just that if there were, they would be substances. Though
substances are supposed to be capable of existing on their own, Descartes
didn’t think that it is possible for us to know them on their own. Whenever we turn to try to say what a
substance is, we end up seizing just on one or more of its affections. We can’t say much more about substance
itself than that it is the thing that is considered to have the
affections. This is a foreshadowing of
something that was to be made much of by later philosophers, particularly in
eighteenth century Among the affections or properties of a substance there is one that is its “principal attribute.” The principal attribute of a substance is the affection or property that it has to have in the sense that the substance is inconceivable apart from it, so that were the principal attribute to be removed the substance would be destroyed. It is also “principal” in the sense that all the other attributes of the substance are supposed to be merely modifications or “modes” of the manner in which this principal attribute is present. Because all the other affections and properties are conceived as modifications of the principal attribute, Descartes noted that it is more proper to consider the principal attribute to be “in” the substance rather than to be a modification of the substance. To describe it as a modification would be to suggest that the substance could be differently modified. But it could not be. To lose the principal attribute is tantamount to destruction of the substance. The introduction of the notion that principal attributes are “in” substances rather than being modifications of substances is motivated by the case of God, the divine substance. God cannot properly be described to be modified in any way, since that would imply passivity and alteration, whereas God is unchangeable and cannot be operated on by anything else. God must, moreover, have infinite attributes. But they must be “in” God rather than modifications of God. The notion, once forged, can be applied to the principal attribute of created substances. We might wonder why a created substance could only have one principal attribute. Descartes did not explain why in the Principles, but he would likely have answered that were there an attribute of a substance that is not merely a modification of the principal attribute, it would be possible to conceive of these two attributes apart from one another. But substance is defined in terms of whatever things can be conceived apart from one another. So the separate conceivability of two attributes would imply the existence of distinct substances that possess these attributes. Necessarily, therefore, each substance could only have one principal attribute, though that attribute might be modified in various ways. In light of this analysis, Descartes declared that we can consider ourselves to clearly and distinctly perceive a substance when we have identified its principal attribute, and distinguished it from any other property. The principal attribute of intellectual or thinking substances is thought, and the principal attribute of material or extended substances is extension. We can also clearly and distinctly perceive those modes that belong to all substances in general (duration, order, and number) as long as we perceive them as modes, and not as substantial things in their own right. Time, a spatial container in which things might be placed in a certain order, and number are not things in their own right, in Descartes’s view. Time is just a mode of substances: their duration. Order is just a relation between substances with reference to their duration (which endure at the same time as one another or at successive times as measured by coexistence with earlier and later states of the endurance of some third thing) or to their disposition relative to surrounding bodies, and would disappear were there no substances being related. And number is always the number of some collection of things and not something that could exist on its own apart from any things. Because these modes are so general, we are tempted to think they are something apart from substances that governs them. But they are not and it is the other way around: they derive from the way substances are. A similar mistake with regard to the modes of thought and extension is not as easy to make since there we find an obvious dependence of the mode on just some substances and not a commonality with all. Descartes proceeded to draw a distinction between modes and qualities. As already noted, a mode is a specific way in which the principal attribute of a substance is modified. So extension can be modified by being larger or smaller, square shaped or round shaped, divided into some number of parts or at rest, and so on. Similarly, thought can take the form of ideas of different things, of judgments, of sensations, of passions, etc. A quality is a mode that is picked as the characteristic feature of a kind of thing. So the mode of having a surface that is everywhere equidistant from the center is the quality of globes — the mode of extension that is characteristic of that kind of thing. Modes may also be considered as things that are found, as it were, “in the mind” that thinks about the thing rather than in the thing itself. This is the case with time considered as something that is measured by the motion of certain bodies considered to be in uniform, cyclical motion, like the Sun, or with number. Things that endure without changing possess duration as a mode, but the mind is only able to measure the length of that duration through reference to something else that changes over time (say by moving in uniform cyclical motion). But it is one thing to be able to measure the length of an interval and it is another for there to be an interval of time. The latter can exist without the former. The former is a mode merely in the mind of the thing that considers the thing that has duration. Number, similarly is dependent on how the mind that considers things decides to group them. A brick is one brick, but many bricks are one house and many houses one city, so when you call something “one” or some larger number, the number you attribute is not a mode of the thing but of the manner in which you are considering the thing. What has been said of number is also true of all universals: they are dependent on how the mind chooses to collect things together and are not, as Plato maintained, things that exist independently and that dictate what groups or species things ought to be considered to fall into. Just as there is no fact of the matter about whether a soldier is to be counted as one solder, or one of twenty in a platoon or one of hundreds in an army, so there is no fact of the matter about whether this particular object is to be considered as belonging to this group (e.g. female by sex) or that one (e.g. female by gender). It depends just on how the mind chooses to consider things. It is not clear whether Descartes was a nominalist or a conceptualist about universals, but he certainly was not a realist. He did not believe that there are universal things like “the one” or “the good.” He did think that there are terms that are used to name universals, but he also thought that what these terms are properly taken to name is certain universal ideas. However it is not clear whether he considered these ideas to be particular ideas that are simply used as signs to stand for a range of things that resemble them in some way, or whether he thought that they are abstract ideas by means of which we conceive just the aspect in which the things in the resemblance class resemble one another. This is a difficult interpretative issue that turns on how to understand what he had to say about real, modal, and conceptual distinctions (to be discussed below). At Principles I.59, all he said is that universals arise when “we make use of one and the same idea for thinking of all individual items which resemble each other,” leaving it unclear whether the idea is a particular idea of a particular thing in all its particularity or just an abstract idea of the resembling feature in the thing separated from all its other properties and accidents. However, while he wrote that “we apply one and the same term to all the things which are represented by the idea in question, and this is the universal term,” it is clear from what he said later that it is the idea that “wears the pants” as it were. It is not some practice governing the use of the term that leads us to put certain things together in a collection and leave others out, but the idea that we use to think of the resembling things that serves as the meaning of the term. Terms can be confused through being used on their own in discourse without carefully attending to the ideas that they are supposed to name (Principles I.74). That couldn’t happen if the meaning of the term was just how it is used. In addition to laying out this position on universals, Descartes set out to integrate what he had said about substances, attributes, and modes with traditional philosophical discourse, which had employed the categories of genus, species, difference, property, and accident. All of these notions are redefined in his own terms. A genus is just a very high order universal idea — one that collects a large class of resembling things underneath it. A species is an idea used to represent all those things in the large resemblance class that resemble one another in some further way, special to just some members of the larger group. So, for example, if the large group is “animals,” the species might be “mammals,” or “fish.” If it is “minerals,” the species might be “salt” or “sulphur.” The resembling feature that distinguishes the members of one species from those of other species (e.g., having glands that secrete milk) is the difference. In Descartes’s terms, “species” are most properly considered to be sorts of the two main types of created substances, and differences are their defining features. One of the things Descartes goes on to argue for over subsequent sections of the Principles is that all the species of animal, mineral, and vegetable that have been distinguished are really not distinguished from one another by such differences as hardness or weight or salinity or acidity, etc., but only by how the extended parts that compose these bodies are shaped and moving. Properties are things that follow necessarily from the difference of a species. Consequently, they are always present even though they are not to be identified with that difference. An example is having a hypotenuse that is equal to the square root of the sum of the squares of the lengths of the sides. This is a property of a right-angled triangle as it is inseparable from having a right angle. Accidents, in contrast, are different modes or ways in which the difference might be modified. Being isosceles is an accident of a right angled triangle. The doctrine of distinctions. Much that Descartes has said so far, and much that he will say, depends on how we understand what he had to say about distinctions, which is simultaneously one of the most important and one of the most difficult aspects of his thought. Distinctions are important because it is in virtue of them that we tell substances and attributes apart and make decisions about what things are clearly and distinctly perceived to be the way they are and what judgments about things are merely the product of juvenile preconceptions. Descartes recognized three types of distinction: real, modal, and conceptual. A real distinction is a distinction between two or more substances, such as the distinction between two or more created minds, the distinction between a mind and a body, or the distinction between any spatial part of a body and the surrounding parts. In the case of a real distinction, each of the distinguished things can be conceived without conceiving the other, and this is important because it means that we can appeal to the power of God to argue that whatever can be really distinguished must be in principle capable of separate existence and hence must be a substance in its own right. Mind is ultimately distinguished from body because, in Descartes’s opinion, our conception of mental operations carries with it no idea of the motion of extended and shaped particles, and our conception of the motion of extended and shaped particles likewise carries with it no idea of any mental operation that might be constituted by that motion. Real distinctions are thus at the root of the clear and distinct perception of different substances. A modal distinction is a distinction between a substance and its mode or between two modes of the same substance. In this case the substance can be conceived apart from the mode(s), but the mode(s) cannot be conceived apart from the substance. A piece of wax, for instance, must be conceived to be extended, but its extension could be modified as square or round, as cut into arbitrarily many pieces, or as modified in any of a number of other ways. It could even be modified with respect to size (it expands when heated). No one of these particular modifications is necessary. The wax could exist without being modified in this particular way. So while they cannot be conceived apart from it (that is, apart from some extended substance), it (some extended substance) can be conceived apart from them. Likewise, when two modes are considered, each of them can be conceived apart from the other (sometimes necessarily so as they are contrary like being round and being square), but neither of them can be conceived apart from being conceived as modes of one and the same substance. In cases where we conceive of modes of different substances, like doubting and being square, the distinction is not modal but real as it involves conceiving distinct substances that possess the different modes. The modal distinction thus serves to lead us to clearly and distinctly perceive what modes are related to what substances. A conceptual distinction is a distinction drawn between a substance and its attribute or between attributes of the same substance. In the latter case, no more than one of the attributes could be a “principal” attribute, but that does not pose a problem because in addition to principal attributes there are properties and attributes of substances in general such as duration or number. In these cases neither of the distinguished things can be conceived apart from one another. Yet, despite not being able to effect any separation, we are able to be cognizant of a difference. We distinguish substance from its attributes even though we are only supposed to be able to conceive of substance through conceiving of its attributes. We likewise distinguish the duration of a substance from its extension, or its duration from its number. Descartes went no further towards explaining how this might be possible. Obviously, we do draw these distinctions, and he seems to have been content with that fact and reluctant to inquire any further into its basis. Sensations, Emotions and Appetites. Significantly, it is only after having laid down this doctrine of distinctions that Descartes turned to discuss what he had earlier identified as a fourth class of mode: modes that do not belong to either body alone or mind alone but that seem to involve some sort of relation between the two. These are appetites, emotions, and sensations. Appetites, emotions, and sensations are modes of thought that are unique in that they do not depict bodies, as ideas do, but are instead taken to be caused by a particular body to which we are intimately connected. They may also involve desires to move this body in particular ways, or to tend to its needs in particular ways. While no one questions that appetites and emotions are ultimately mental states, despite their causal origin in the body and their reference to the body, we have all, since we were children, judged that our sensations resemble things existing outside of us in bodies. Even pains, which are not taken to be qualities of inanimate things, are taken to be qualities inhering in specific parts of our own extended bodies. I feel an itch, for example, and when I feel it I always feel it in a certain place: the place that I reach to in order to scratch it. And I have never felt tempted to try to reach into my mind to scratch an itch I felt there. That is not where I feel itches. I feel them at places on my body, which is to say that I feel them at specific locations in space. Similarly, when I see colours, I necessarily see them as extended and located, even if only at a point. A colour that had no extension or no location would vanish. And therefore I likewise consider colours to be things that exist in space and that accordingly “modify” extended things in certain ways, as do pains and other sensations. Indeed, I consider these judgments to be so clearly and distinctly perceived as to be certain and indubitable. The distinction between colour or pain and extension is at least a modal if not merely a conceptual distinction. I may be able to conceive of extension as not having this or that colour. But I cannot conceive of colourless extension, or, if I do, it is for that reason also without shape, size or limits. It is only in virtue of contrasts between different colours or different tactile qualities (like pains or sensations of pressure) that I can conceive of edges, lines, and limits in space and so only through conceiving of those things that I can conceive of shapes and sizes. So I would consider sensible qualities (at least the visual and tangible ones) to be only “conceptually distinct” from shape and size, and if shape and size are only “modally distinct” from extension, I would consider visible and tangible qualities to likewise be only modally distinct from extension. In the tangible qualities I would include such “modifications” of pressure sensations as hardness, heaviness, malleability, brittleness, viscosity, fluidity, and so on. And I would be tempted to expand the list and consider tastes and smells, and with them such qualities as acidity, salinity, and sulpherousness to be “modifications” of bodies as well. Yet, Descartes would have none of this. He maintained that, while things like pain and colour “are clearly and distinctly perceived when they are regarded merely as sensations or thoughts … when they are judged to be real things existing outside our mind, there is no way of understanding what sort of things they are” (Principles I.68). We might well ask why not. It seems on the contrary that we understand perfectly well what they are and that they are exactly what they appear to be. We understand them to be such things as colours that have various hues, saturations, and brightnesses, that exhibit an intrinsic order among themselves, that put us in a position to declare such intuitive truths as that orange is more like red than it is like green, and that are “really distinct” from one another (so two different colours could not belong to the same substance at the same time), only “conceptually distinct” from shape and size and location (because all colours are somewhere), and only “modally distinct” from extension. To understand all of these things about colour is to understand something. Indeed, it is to understand a great deal. Descartes maintained that “If someone says he sees colour in a body or feels pain in a limb, this amounts to saying that he sees or feels something there of which he is wholly ignorant, or, in other words, that he does not know what he is seeing or feeling” (Principles I.68, my stress). But, on the contrary, I know perfectly well what I am seeing or feeling: I am seeing the very colour I see and feeling the very pain I feel. If I were “wholly ignorant” I would not think I was seeing or feeling anything, green or yellow, scratchy or cold, painful or pleasant. But I am not ignorant of these things. Descartes might have wanted to claim that when someone says they see a colour in a body or feel a pain in a limb, they do not actually mean to say that the colour really is in the body or the pain really is in the limb, but just that there is something in the body or in the limb that causes the thought or sensation that they experience — and that they have no idea what that cause is. But this is to put words in people’s mouths — words that it is just not obvious that they ever intended to utter. When I say I feel a pain in a limb, I mean to localize my pain, not to localize the cause of my pain. Similarly when I say I see a triangular colour patch at 2 o’clock and about 15 degrees elevation, I mean to localize that red colour relative to my current position in space, not the cause of my colour sensation. And it is not clear why I should consider myself to be wrong to do this. Descartes wanted to claim that I can only properly consider colours to be sensations had by minds and not qualities possessed by extended bodies. But I find it far easier to “understand what sort of things they are” when I take colours to be qualities of bodies than when I take them to be sensations in minds. I can understand what it means for the surface of a body to have a colour painted on it. I cannot understand what it means for a mind to have a colour painted on it, particularly not if minds are not extended in space and colours are extended and located in space. Colours (and pains) at least have some affinity with spatial things. There is no evident affinity that they have with minds. Descartes attempted to address these objections over subsequent articles of the Principles. At this point, however, he confined himself to simply charging that people who would say what I have just said about colours and pains are blinded by juvenile preconceptions. But that begs the question. Why we should think that I am blinded by juvenile preconceptions rather than guided by clear and distinct perceptions when I say that colours and pains are only conceptually distinct from shape, size, and location, and only modally distinct from extension? Elsewhere, Descartes went into more detail on this matter, and it is worth pausing to consider what he said at these other points. The dreaming argument. One reason to suppose that colours and pains are not clearly and distinctly perceived to be qualities of bodies is provided by the dreaming argument. Suppose we are the inhabitants of a spirit world who are now asleep and dreaming that they have bodies and that they are located among surrounding objects, even though there are no such things. In that case, nothing that we think exists outside of us actually does, but our dreams themselves nonetheless exist in us. Does it not follow, therefore, that we must be more certain of the existence of our thoughts or sensations of colour than we are of any qualities that may be possessed by external objects, and therefore that we need to have some special reason to suppose that external objects exist and yet further reasons to suppose that they have any particular qualities? It does indeed follow. The problem is that the same argument holds of shapes and sizes. They, too, might only be dreamed up. More to the point, at Principles I.30 Descartes remarked that when it comes to the knowledge we obtain from our senses, “if we notice anything here that is clear and distinct, no matter whether we are awake or asleep, then provided we separate it from what is confused and obscure we will easily recognize — whatever the thing in question —which are the aspects that may be regarded as true.” Let us accordingly take the question to not be one of what exists outside of me, but one of what exists inside of me in my dreams (if they are dreams). More to the point, let us take the question to be whether, regardless of whether we are awake or asleep, it is at all possible to conceive (or dream) of shape or figure without conceiving it to be bounded somehow, and if it is at all possible to conceive of a boundary, edge, or limit without conceiving a contrast in some visible or tangible quality — and likewise whether it is possible to conceive a colour or an itch without conceiving it to be located somewhere in space, and perhaps extended as well. Even in our dreams such things seem inseparable and so merely “conceptually distinct.” The argument from “real qualities” and “material
falsity.”
In parts III and V of his Meditations
on first philosophy, Descartes claimed that there is an imbalance between
what we know of extension and its modes of figure and size and order and
motion and what we know of the other modes discovered by our senses. Figure, size, order, and motion are the
objects of sciences — the sciences of geometry, arithmetic, topology, and
mechanics — and these sciences lead us to discover necessary truths about
extension. These truths are beyond our
power to alter, so that when we discover them we are led to think that they
must be describing something that is the way it is independently of our wills
and so is distinct from us. In
comparison, there are not many truths to be learned about colours. “ This is a clever argument, but it does not address the fact that the modes of extension, especially figure, seem inconceivable apart from contrasting sensible qualities. The science of geometry itself would be impossible were there no colours or other contrasting qualities to employ in drawing the diagrams used in geometrical demonstrations or conceiving geometrical objects in the imagination. If that is the case, then whatever reason we have to ascribe reality to extension and its modes becomes a reason to do the same for at least some sensible qualities. To really drive his point home, Descartes had to insist that it is in fact possible to conceive of the modes of extension apart from conceiving of sensible qualities — and not merely to insist dogmatically on this, but provide a good reason for doing so. The separability argument. This is just what he did. In an argument alluded to by a famous discussion of the essence of a piece of wax in the second part of his Meditations (a discussion that actually has a different point to make), and offered more directly in Principles II.4 and II.11 Descartes attempted to appeal to experience to drive home the point that bodies can be conceived apart from sensible qualities. After all, he claimed, they can be experienced apart from sensible qualities, so it ought to certainly be possible to conceive them this way. The experiences he appealed to were of such things as transparent stones, hard bodies that have been pulverized into such a fine powder that they offer no resistance to the touch, odourless and tasteless bodies, and so on. Since we can experience bodies that lack any given sensible quality, we can conclude that none of those qualities could be essential to body. The problem with this argument is that, like the dreaming argument, it proves too much. Just as we can experience bodies that are colourless or tasteless, so we can experience bodies that are not square or round, not of this size or that size, not in this or that state of motion. If the bare fact that it is possible to experience a body that does not have some specific quality would mean that this quality could not be essential to body then it would follow that there is no figure and no size that is essential to body either. Ultimately, there is no quality that some body cannot be found to be without, be it a sensible quality or a particular mode of extension. And, were Descartes to object that it is nonetheless necessary that a body have some figure and size, even if not any specific one, it could be replied that, if it has some figure and size, then it is equally necessary that it have some sensible quality. Some stones may be transparent, but then they at least resist the touch and hurt when thrown at us; otherwise we would have no reason at all to believe that they exist. Others may have been pulverized to a power so fine as to be imperceptible to the touch, but then they at least have some colour, otherwise we would again find it impossible to say that they exist. Likewise, some stones may not be round, but then they have some other shape. Physiology and the phantom limb. Descartes offered a final argument for the ideality of sensible qualities towards the very close of the Principles (IV.196-198). Like the separability argument, it, too, depends on experience, though the experiences are of a rather different sort — ones in which, rather than experience bodies apart from sensible qualities, we experience sensible qualities apart from bodies and investigate the physical causes of this phenomenon. Descartes cited the example of amputees who report feeling pains that they experience as being located in a limb that does not exist. By itself, this suggests that the pains these people are feeling are not located where they think they are, but are in fact only in their minds. Nor is this a special case. Like Hobbes, he appealed to the case of people who are struck in the eyes and see light, and he also mentioned the case of people who stop their ears and hear a roaring sound. In all of these cases, the qualities that are experienced are only in the mind and not located where they are perceived as being located. Thus, experience itself reveals to us that these sorts of judgments are mistaken. By itself this is not a very compelling argument, because the same point could be made about experiences of shape, size and motion, which Descartes wanted to say are correctly judged to be not merely ideas in us but qualities of external objects. However, there is more to be learned from these sorts of cases than just that we might sometimes be wrong in supposing that there is anything outside of us that resembles what we are currently experiencing. When we inquire into the cause of these experiences by doing some anatomy, we discover the existence of nerves leading from the sense organs to the brain. We further discover that what leads us to experience sensations is impact on or pulling of these nerves at any point along their length. The reason the amputee feels the phantom pain is that the nerve that used to lead to that part of the limb is affected. This led Descartes to infer that when God unified our minds with our bodies, he set things up in such a way that the mind, which is not extended and nowhere in space, would communicate with the body from a certain point in the brain. Information about what is happening in the body would have to be communicated to the mind by nerves extending from the brain to the various parts of the body, inevitably creating the possibility of misperception when these nerves were affected by a disease or some other intrusion along their length, rather than stimulated by objects touching their far ends. God would have set things up so that, in the normal case, where an internal bodily state affects an internal nerve, or an external object touches the end of a nerve that reaches out to the skin or a sense organ, we form in our minds an appropriate sensation. Descartes had one final point to make before launching his capstone argument: when we inspect the nerves that proceed from the different sense organs, we do not find any evident differences between them. We don’t see visual nerves being stained by colours, or auditory nerves vibrating with sounds, nor find any differences in the nerves that might account for how they convey different sorts of qualities up to the brain. We don’t find, for instance, that the olfactory nerves are tubes for the conveyance of scented air or that fluids flow through the nerves from the tongue to convey tastes to the brain. Instead all the nerves look the same, like cords, and they are all affected in the same way, by being touched or pulled. Touch or pull an optic nerve and the subject sees a flash of light. Touch or pull a nerve on one part of the tongue and the subject tastes salt. Touch or pull another part and it tastes sweet. This means that we can’t be experiencing sensible qualities because our nerves are conveying those qualities to our brains. Instead we are experiencing them because we were designed from birth so that, when certain sensory nerves are stimulated, we experience certain sensible qualities. What stimulates the nerve in these cases is not a sensible quality. It is instead a motion of some sort. But if bodies only stimulate the nerves in virtue of touching them, then it would be extravagant were they also supposed to be coloured, or hot or cold, or saline, or acidic, etc. Such qualities, were bodies to possess them, would serve absolutely no purpose in nature. They would not affect us insofar as they had such qualities. They would only affect us insofar as they have shape, size, and motion and impact on our sense organs. And, in all likelihood, they would not affect one another insofar as they had such qualities either. Experience itself teaches us, therefore, that we are in no position to affirm that bodies possess sensible qualities. All that we can be sure of is that we experience these qualities when our nerves are affected by bodies. Or is it? This argument still fails to give satisfaction on the question of how bodies could be conceived to be shaped, sized, or moving if there were not something more to them than space that gives them their bounds and edges. Space is everywhere homogeneous, which suggests that there is nothing to it that could constitute an edge or boundary and that there must be something, be it a quality like colour or a force like pressure or resistance to penetration that produces edges and boundaries. Descartes’s own position on this issue was that differential motion alone would suffice to distinguish the parts of space (Principles II.23). But motion of what? When space is everywhere homogeneous, what are the criteria for picking one part of space and reidentifying it over time and saying that it has changed its place relative to surrounding spaces? I am not just asking how we could come to know that one part of space is moving relative to other parts, but what it would mean for one part of space to move relative to other parts if there is nothing else to distinguish one part of space from another. It is not clear that this notion is even intelligible. But it is time to leave this topic and allow that, whatever the ultimate force of his reasons, Descartes thought otherwise. Descartes’s developmental psychology. We might wonder why Descartes waited until the very end of the Principles before advancing his best and most powerful argument for denying the external reality of sensible qualities. The answer is that the argument presupposes the existence of an external world of extended and moving things, the existence of our own bodies, an account of how our minds are united with our bodies, and an account of all the phenomena of nature that succeeds at making it plausible that all these phenomena are produced only by the shape, size, motion, and impact of bodies. It was only at the end of the Principles that Descartes was in a position to claim that he had done all of these things. At the close of the first part of the Principles the best he could do was make unjustified assertions. He did, however, attempt to explain how it is that people have fallen into the error of assuming that sensible qualities exist in bodies. This explanation is rooted in a kind of developmental psychology, presented in the opening paragraph of a brief discussion of the principal causes of error, with which Part I of the Principles concludes. According to the account, when we began life as infants we experienced ideas of shapes and ideas of sensible qualities separately. The shapes we saw and felt were colourless and without tangible quality, and the colours and tactile sensations we experienced were aspatial and unordered. We considered these sorts of things, and indeed all our sensations, to be merely qualities of our own thoughts. This changed when, when we began to move around. We then noticed a distinction between those things we carry around with us wherever we go and those that remain behind when we move away. Principal among these things are shapes, which remain where they are relative to other shapes when we move our eyes or heads or bodies. So we came to distinguish shapes from ourselves and to consider them to exist apart from us. However, a further experience led us identify shapes with colours and other sensible qualities. This is the experience of only encountering particular sensations when in the presence of certain shapes. As a consequence of this experience, we first came to think of the shapes as being the causes of the sensations, and then to think of them as having the same qualities as the sensations (supposing that the cause must be like its effect). Indeed, we went so far as to consider the sensible qualities to be more real than the shapes, and to consider things that are merely extended without affecting our senses much (e.g. air) to be less real than those that affect our senses more. We also supposed that objects have exactly those sizes and shapes they appear to have (for instance, that the Earth is flat, and the heavenly bodies small.) It was only later that we learned the error of many of these opinions, and by that time they had become so entrenched in our thought that they have persisted, despite our knowing better. Thus, just as we continue to “see” (that is, judge) the Sun as orbiting around the Earth and as being only a few feet across, even though we know better, so we continue to “see” (that is, judge) colours to be on the surfaces of bodies and pains to be located in body parts — the only difference is that it we have become so blinded by the latter preconception that, despite having once been able to see shapes apart from colours or other sensible qualities, we are no longer able to do so, even though we know better. This error is compounded by the fact that we find it difficult to think about things that cannot be readily sensed or imagined. So, though we could do, say, analytic geometry (which Descartes invented) and in this way come to think of the objects of geometry in terms simply of numerical formulas and avoid reliance on visual diagrams, which always import the unnecessary element of colour), we find it too hard to do so and revert to what is sensible. A further problem is that we have a tendency to think by making use just of the words we use to name ideas, and perform calculations with these words rather than recover and inspect the ideas that they name. This introduces the possibility of ambiguity and equivocation, as words can drift away from the ideas they were devised to name and so mislead us by leading us to thing of the wrong thing or confuse things that are really distinct. Substance, real
qualities, transubstantiation, and the Eucharist.
At Principles I.25 Descartes had declared
that were God to reveal some truth to us that it is beyond the natural reach
of our cognitive powers, we should not refuse to believe it even though we
might not clearly understand how it could be possible. In Principles I.76,
the last article of Principles I,
he went even further, declaring that revelation ought to be recognized as
more certain than anything else — suggesting that we should not only accept
revealed truths that go beyond anything natural reasoning or perception can
discover, but also ones that contradict what natural reasoning and perception
can discover. It is not without
reason that these articles were inserted in what is otherwise a purely
philosophical treatise, because there are aspects of Descartes’s
philosophy that are contrary to received Christian doctrine. In subsequent parts of the Principles, for example, Descartes was
to go on to declare, in defiance of the Creation story of the book of Genesis
of the Christian Bible, that God needed to do no more than create a block of
matter (or space, which is the same thing in his estimation) and inject a
quantity of motion into it which he would then preserve in accord with the laws
of motion and collision, and a world like the one we see around us would
evolve of its own accord, without needing any further special creative acts
on God’s part. Even today, this is a
doctrine that would not go over well in certain circles. Recognizing that this
account of creation is contrary to the Book of Genesis, a body of supposedly
revealed truths, Descartes was happy to appeal to articles I.25 and I.76, and
declare that while God could have
created the world in the way Descartes had described, we must accept the
revealed truth that God in fact engaged in the more laborious six-day
enterprise described in Genesis. As a matter of fact,
the concession is a very small one, whether viewed from the Cartesian or the
theological point of view. From the Cartesian
point of view, allowing that God unnecessarily spent six days creating the
world when it would just as well have evolved on its own does nothing to
contest the correctness of the principles of Cartesian physics, which is the
main point Descartes was seeking to establish. And even from the theological point of
view, allowing that it would have been even possible that the world could
have evolved on its own is moot, given Descartes’s
views on constant creation. Those
views entail that the universe could have really evolved “on its own” on any
significant sense, because apart from God’s act of recreating it and all its
parts in accord with the laws of motion and collision from moment to moment,
it would simply vanish. Divine agency
is far from being read out of nature by allowing that the universe could have
evolved “on its own” when it takes a constant act on the part of God to
preserve anything in existence from one moment to the next. There was, however, a
more serious issue motivating the official declaration of respect for
revelation at Principles I.76, one
grounded in the material we have just examined. According to the Christian Gospels, during
his last supper with his disciples, Jesus, the founder of the Christian
religion, reportedly broke bread and poured wine and declared both to be his
body and blood, inviting his disciples to eat and drink them. From the times of the early Christian
church, this incident had been ceremonially re-enacted at religious
ceremonies (much to the horror and disgust of the cultivated, cosmopolitan
pagans of Such doctrines were
among those that came under scrutiny during the Protestant Reformation, both
on account of the power they invested in Priests and higher religious
authorities, and on account of the crude superstition they encouraged. For the Protestants, the age of miracles is
past. Christ’s crucifixion had been
the great sacrifice that had redeemed the human race from sin (or, at least,
those of them pre-elected for salvation), and to suppose that miracles of any
sort would continue to occur would be to impiously suggest that that
sacrifice had been insufficient to attain its end. Accordingly, the Protestants maintained
that Christ should be understood to be only spiritually present in the bread
and wine (when they tolerated the ceremony at all). The Catholics
denounced this as a patent heresy.
Christ had reportedly said “This is my body … this is my blood.” The Catholics took this to be meant
literally. And they insisted that
ordained Priests acquired the power to re-enact this miracle during their
religious ceremonies. Of course, the
bread and wine continue to look like bread and wine, even after the miracle
has been performed (though there were occasional reports of more literal
sightings). But, according to the
Catholics, they have really been transformed or “transubstantiated,”
notwithstanding the appearances. Over
the course of the middle ages, this belief had come to be underwritten by the
Aristotelian notions of substance and real quality. This is where the problems for Descartes
start to come in. At the moment when
the priest “consecrates” the bread and wine, it was thought that the essence
or substantial form of the host changes from that of bread to that of the
body and blood of Christ. However, all
the merely “accidental” qualities that were previously evident in the bread
and wine continue to be there (which is why it still looks, feels, tastes,
and smells the same). However, these
qualities subsist outside of any substance (the substance of Christ’s body
and blood was not supposed to take on these accidental qualities but to exist
apart from them). Crucial to this
explanation of the miracle is the notion that sensible qualities like colour,
smell, and taste, are real qualities that exist outside of us and that can
even exist apart from the substances in which they normally inhere. Even more interestingly, this was taken to
extend, not just to the sensible qualities of smell, taste, and colour, but
also to the extension, shape, size, motion and solidity of the bread and
wine. The substance of Christ’s body
was supposed to exist distinctly from the particular extension of the bread
and wine, a detail that allowed the Catholics to maintain that the whole of
the body of Christ could be present in even very and oddly shaped small
fragments of the bread and wine. One does not need to
read far into Principles I.48-76 to
see how unfriendly to this account of the Eucharist Descartes’s
philosophy was. Not only did Descartes
reject the real existence of sensible qualities outside of our minds, he
insisted that substances have principal attributes, and that they are only
“formally” distinct from these attributes.
The notion that extension might subsist apart from the substance that
is extended was unacceptable to Descartes.
But in a time when the doctrine of the Eucharist had become a
flashpoint between Catholics and Protestants, this was to takes sides with
the Protestants. The problem was once
again raised by Antoine Arnauld in his fourth set
of objections to Descartes’s Meditations on First Philosophy.
Arnauld wrote: But what I see
as likely to give the greatest offence to theologians is that according to
the author’s doctrines it seems that the Church’s teaching concerning the
sacred mysteries of the Eucharist cannot remain completely intact. We believe on
faith that the substance of the bread is taken away from the bread of the
Eucharist and only the accidents remain. These are extension, shape, colour,
smell, taste and other qualities perceived by the senses. But the author
thinks there are no sensible qualities, but merely various motions in the
bodies that surround us which enable us to perceive the various impressions
which we subsequently call ‘colour,’ ‘taste’ and ‘smell.’ Hence only shape,
extension and mobility remain. Yet the author denies that these powers are
intelligible apart from some substance for them to inhere in, and hence he
holds that they cannot exist without such a substance. … Further, he
recognizes no distinction between the states of a substance and the substance
itself except for a formal one; yet this kind of distinction seems
insufficient to allow for the states to be separated from the substance even
by God. Questioning the
mystery of the Eucharist was something that Descartes wanted, at all costs to
avoid, at least as much because he wanted to popularize his philosophy within
the French universities as because he feared the possibility of prosecution in
an age when heretics could still be burned at the stake. Two paths were open to him. One was circumspection of the sort we have
seen him recommend to Regius, cited at the end of
Chapter 7 coupled with accommodation of the sort noted above when dealing with
the Creation story of Genesis. Taking
this path would mean invoking article I.76 of the Principles to grant the revealed truth that God can separate
substances from their principal attributes and perhaps even make sensible
qualities subsist outside of the mind, even though it not only goes beyond
but is in some respects contrary to what we can clearly and distinctly
perceive. Descartes could still
maintain that while we have excellent reasons for concluding that external
objects must be extended and so must possess the modifications of which
extension is capable, we do not have the same reasons to think that they must
have any other sort of qualities. Only
revelation can assure us of that, and even granting that it does so, we have
no need to suppose that bodies any other qualities apart from religious
purposes. When giving scientific
explanations, all we need to invoke are extension and its modes. But in the end, this
was a path that Descartes could not take.
Allowing for even the possibility of the existence of real qualities
would undermine his physics, which was too deeply invested in the notion that
bodies can have no other qualities than those that arise from extension. So Descartes took a different route. He attempted to reconcile his philosophy
with the doctrine of transubstantiation.
His reply to Arnauld invoked a distinction
between the “superficies” or outer surface of a body (including all its
pores, if it has them, or the outlines of all of its parts, if it has
independently movable parts) and the material contained within this
superficies. The latter could change
while the former remains the same he maintained. But were this to happen, the body would
continue to affect our sense organs in the same way, and so bring about the
same sensations in us, even though it is constituted of material of an
entirely different kind (that is, even though its ultimate parts are
differently shaped and moving). This,
in his estimation, constitutes a far more intelligible explanation of the
primary doctrine, that of transubstantiation, than that offered by the
Scholastics with their commitment to real qualities. It preserves the essential tenet that the
substance changes while the way it acts on us remains the same while at the
same time avoiding the Protestant heresies on this topic. This did not go all
the way to resolve the problem, however, and it was not intrinsically very
satisfying. It did not account for how
an extended substance could be separated from its modes of size, shape, and motion,
which was also a part of the doctrine, and it raised questions about how far
the substance could have been really transformed if it continued to occupy
the same superficies, given what Descartes had to say about how extended
substances are distinguished from one another. When pressed on these issues, Descartes
became very reticent to go into detail, and turned to the claim that it is
union with a mind that really makes a human substance the kind of thing it is. The same would have to hold of the substance
of Christ insofar as it shares any physical nature. However, this was all too close to the
Protestant view that Christ is merely “spiritually” present in the
sacrament for comfort, and Descartes
knew it because he asked those to whom he had revealed these speculations to
not reveal his identity. Mesland, a Jesuit who corresponded with Descartes about
these topics and who may have made some moves in the direction of getting Descartes’s philosophy endorsed by the Jesuits, was sent
off to the missions in ESSAY QUESTIONS AND RESEARCH PROJECTS
1. How does Descartes’s position on the nature of universals fit in
with the traditional debate between realists, who take there to be universal
things existing in reality, nominalists, who
maintain that everything that exists is a particular and that the only things
that are universals are certain words that are used to stand for groups of
particulars, and conceptualists, who maintain that while there are no
universal things there may be abstract ideas in the mind that represent just
the common or general features of groups of things?
2. Outline Descartes’s account of real, modal, and conceptual
distinctions and explain to what extent the claims of Principles I.48-76
concerning mind, body, and sensation are grounded in that account.
3. Is Descartes’s
notion of conceptual distinctions ultimately intelligible? If two things cannot be separated from one
another, how can they be at all distinct?
If they are distinct, how can they be inseparable? How can an attribute such as thought or
extension be conceptually distinct from a substance such as mind or body if
the substance is inconceivable apart from the attribute? What are we conceiving when we conceive a
distinction in this case?
4. Is there
any way that Principles I might be
read as itself justifying the claim that the
qualities revealed to us by our senses do not exist outside of us in
bodies? If this claim is only
justified in later sections of the Principles,
is it appropriate that it be relied on so heavily in this section? |
