Delphi Collected Works of René Descartes

by René Descartes

  As for the second, which one may take to be the element of air, I conceive of it also as a very subtle fluid in comparison with the third; but in comparison with the first there is need to attribute some size and shape to each of its parts and to imagine them as just about all round and joined together like grains of sand or dust. Thus, they cannot arrange themselves so well, nor so press against one another that there do not always remain around them many small intervals into which it is much easier for the first element to slide than for the parts of the second to change shape expressly in order to fill them. And so I am persuaded that this second element cannot be so pure anywhere in the world that there is not always some little matter of the first with it.

  Beyond these two elements, I accept only a third, to wit, that of earth. Its parts I judge to be as much larger and to move as much less swiftly in comparison with those of the second as those of the second in comparison with those of the first. Indeed, I believe it is enough to conceive of it as one or more large masses, of which the parts have very little or no motion that might cause them to change position with respect to one another.

  If you find it strange that, in setting out these elements, I do not use the qualities called “heat,” “cold,” “moistness,” and “dryness,” as do the philosophers, I shall say to you that these qualities appear to me to be themselves in need of explanation.21 Indeed, unless I am mistaken, not only these four qualities, but also all the others (indeed all the forms of inanimate bodies) can be explained without the need of supposing for that purpose any other thing in their matter than the motion, size, shape, and arrangement of its parts. In consequence whereof I shall easily be able to make you understand why I do not accept any other elements than the three I have described. For the difference that should exist between them and the other bodies that the philosophers call “mixed” or “composite” consists in the forms of these mixed bodies always containing in themselves some qualities that are contrary and that counteract one another, or at least do not tend to the conservation of one another, whereas the forms of the elements should be simple and not have any qualities that do not accord with one another so perfectly that each tends to the conservation of all the others.

  Now I could not find any such forms in the world except the three I have described. For the form I have attributed to the first element consists in its parts moving so extremely fast and being so small that there are no other bodies capable of stopping them. Beyond that, they require no determinate size or shape or position. The form of the second consists in its parts having such a middling motion and size that, if there are in the world many causes that could increase their motion and decrease their size, there are just as many others that can do exactly the opposite. Thus, they always remain balanced as it were in that same middling condition. And the form of the third consists in its parts being so large or so joined together that they have the force always to resist the motions of the other bodies.

  Examine as much as you please all the forms that the diverse motions, the diverse shapes and sizes, and the different arrangement of the parts of matter can lend to mixed bodies. I am sure you will find none that does not contain in itself qualities that tend to cause it to change and, in changing, to reduce to one of the forms of the elements.

  Flame, for example, the form of which demands its having parts that move very fast and that in addition have some size (as has been said above), cannot last long without being corrupted. For either the size of its parts, in giving them the force to act against other bodies, will be the cause of the diminution of their motion, or the violence of their agitation, in causing them to break upon hurtling themselves against the bodies they encounter, will be the cause of their loss of size. Thus, little by little they will be able to reduce themselves to the form of the third element, or to that of the second, and even also some of them to that of the first.22 Thereby you can see the difference between this flame, or the fire common among us, and the element of fire I have described. You should know also that the elements of air and of earth (i.e. the second and third elements) are none the more similar to that grosser air we breathe nor to this earth on which we walk, but that generally all the bodies that appear about us are mixed or composite and subject to corruption.

  And nevertheless one need not think therefore that the elements have in the world no places that are particularly destined for them and where they can be perpetually conserved in their natural purity.23 On the contrary, each part of matter always tends to be reduced to one of their forms and, once having been reduced, never tends to leave that form. Hence, even if God at the beginning had created only mixed bodies, nevertheless since the world began all these bodies could have had the chance to leave their forms and to take on those of the elements. Thus, there is now much reason to think that all the bodies that are large enough to be counted among the most notable parts of the universe each have the form of only one of these elements alone, and that there cannot be mixed bodies anywhere but on the surfaces of these large bodies. But there, of necessity, there must be some mixed bodies; for, the elements being of a very contrary nature, it cannot happen that two of them touch one another without acting against each other’s surfaces and thus lending the matter there the diverse forms of these mixed bodies.

  Apropos of this, if we consider in general all the bodies of which the universe is composed, we will find among them only three sorts that can be called large and be counted among the principal parts, to wit, the sun and the fixed stars as the first sort, the heavens as the second, and the earth with the planets and the comets as the third. That is why we have good reason to think that the sun and the fixed stars have no other form than that of the wholly pure first element, the heavens that of the second, and the earth with the planets and comets that of the third.

  I link the planets and the comets with the earth because, seeing that they, like she, resist light and reflect its rays, I find no difference between them. I also link the sun with the fixed stars and attribute to them a nature totally contrary to that of the earth because the action alone of their light is enough to make me know that their bodies are of a very subtle and very agitated matter.

  As for the heavens, in as much as they cannot be perceived by our senses, I think I am right in attributing to them a middle nature between that of the luminous bodies whose action we perceive and that of the solid and heavy bodies whose resistance we perceive.

  Finally, we do not perceive mixed bodies in any other place than on the surface of the earth.24 And, if we consider that the whole space that contains them (i.e. all that which stretches from the highest clouds to the deepest mines that the greed of man has ever dug out to draw metals from them) is extremely small in comparison with the earth and with the immense expanses of the heavens, we will easily be able to imagine to ourselves that these mixed bodies taken all together are but as a crust engendered on top of the earth by the agitation and mixing of the matter of the heavens surrounding it.

  And thus we will have reason to think that it is not only in the air we breathe, but also in all the other composite bodies right down to the hardest rocks and the heaviest metals, that there are parts of the element of air mixed with those of earth and, consequently, also parts of the element of fire, because they are always found in the pores of the element of air.

  But one should note that, even though there are parts of these three elements mixed with one another in all bodies, nonetheless, properly speaking, only those which (because of their size or the difficulty they have in moving) can be referred to the third element compose all the bodies we see about us. For the parts of the two other elements are so subtle that they cannot be perceived by our senses. One may picture all these bodies as sponges; even though a sponge has a quantity of pores, or small holes, which are always full of air or water or some other liquid, one nonetheless does not think that these liquids enter into its composition.

  Many other things remain for me to explain here, and I would myself be happy to a
dd here several arguments to make my opinions more plausible. In order, however, to make the length of this discourse less boring for you, I want to wrap part of it in the cloak of a fable, in the course of which I hope that the truth will not fail to appear sufficiently and that it will be no less agreeable to see than if I were to set it forth wholly naked.

  CHAPTER SIX Description of a New World, and on the Qualities of the Matter of Which it is Composed

  For a short time, then, allow your thought to wander beyond this world to view another, wholly new one, which I shall cause to unfold before it in imaginary spaces. The philosophers tell us that these spaces are infinite, and they should very well be believed, since it is they themselves who have made the spaces so.25 Yet, in order that this infinity not impede us and not embarrass us, let us not try to go all the way to the end; let us enter in only so far that we can lose from view all the creatures that God made five or six thousand years ago and, after having stopped there in some fixed place, let us suppose that God creates from anew so much matter all about us that, in whatever direction our imagination can extend itself, it no longer perceives any place that is empty.

  Although the sea is not infinite, those who are on some vessel in the middle of it can extend their view seemingly to infinity, and nevertheless there is still water beyond what they see.26 Thus, even though our imagination seems to be able to extend itself to infinity, and this new matter is not assumed to be infinite, we can nonetheless well suppose that it fills spaces much greater than all those we shall have imagined. Indeed, in order that there be nothing in all this that you could find to blame, let us not permit our imagination to extend itself as far as it could, but let us purposely restrict it to a determinate space that is no greater, say, than the distance between the earth and the principal stars of the firmament, and let us suppose that the matter that God shall have created extends quite far beyond in all directions, out to an indefinite distance. For there is more reason, and we have much better the power, to prescribe limits to the action of our thought than to the works of God.

  Now, since we are taking the liberty of imagining this matter to our fancy, let us attribute to it, if you will, a nature in which there is absolutely nothing that anyone cannot know as perfectly as possible. To that end, let us expressly assume that it does not have the form of earth, nor of fire, nor of air, nor any more particular form (such as wood, or a stone, or of a metal); nor does it have the qualities of being hot or cold, dry or moist, light or heavy, or of having some taste, or smell, or sound or color, or light, or suchlike, in the nature of which one could say that there is something that is not clearly known by everyone.27

  Let us not also think, on the other hand, that our matter is that prime matter of the philosophers that has been so well stripped of all its forms and qualities that nothing more remains that can be clearly understood.28 Let us rather conceive of it as a real, perfectly solid body, which uniformly fills the entire length, breadth, and depth of the great space at the center of which we have halted our thought. Thus, each of its parts always occupies a part of that space and is so proportioned to its size that it could not fill a larger one nor squeeze itself into a smaller one, nor (while it remains there) suffer another to find a place there.

  Let us add further that this matter can be divided into any parts and according to any shapes that we can imagine, and that each of its parts is capable of receiving in itself any motions that we can also conceive. Let us suppose in addition that God truly divides it into many such parts, some larger and some smaller, some of one shape and some of another, as it pleases us to imagine them. It is not that He thereby separates them from one another, so that there is some void in between them; rather, let us think that the entire distinction that He makes there consists in the diversity of the motions He gives to them. From the first instant that they are created, He makes some begin to move in one direction and others in another, some faster and others slower (or indeed, if you wish, not at all); thereafter, He makes them continue their motion according to the ordinary laws of nature. For God has so wondrously established these laws that, even if we suppose that He creates nothing more than what I have said, and even if He does not impose any order or proportion on it but makes of it the most confused and most disordered chaos that the poets could describe, the laws are sufficient to make the parts of that chaos untangle themselves and arrange themselves in such right order29 that they will have the form of a most perfect world, in which one will be able to see not only light, but also all the other things, both general and particular, that appear in this true world.

  But, before I explain this at greater length, stop again for a bit to consider that chaos, and note that it contains nothing that is not so perfectly known to you that you could not even pretend not to know it. For, as regards the qualities that I have posited there, I have, if you have noticed, supposed them to be only such as you can imagine them. And, as regards the matter from which I have composed the chaos, there is nothing simpler nor easier to know among inanimate creatures. The idea of that matter is so included in all those that our imagination can form that you must necessarily conceive of it or you can never imagine anything.

  Nonetheless, because the philosophers are so subtle that they can find difficulties in things that appear extremely clear to other men, and because the memory of their prime matter (which they know to be rather difficult to conceive of) could divert them from knowledge of the matter of which I speak, I should say to them at this point that, unless I am mistaken, the whole problem they face with their matter derives only from their wanting to distinguish it from its own proper quantity and from its outward extension, i.e. from the property it has of occupying space. In this, however, I am willing that they think themselves correct, for I have no intention of stopping to contradict them. But they should also not find it strange if I suppose that the quantity of the matter I have described does not differ from its substance any more than number differs from the things numbered. Nor should they find it strange if I conceive of its extension, or the property it has of occupying space, not as an accident, but as its true form and its essence. For they cannot deny that it is quite easy to conceive of it in that way. And my plan is not to set out (as they do) the things that are in fact in the true world, but only to make up as I please from [this matter] a [world] in which there is nothing that the densest minds are not capable of conceiving, and which nevertheless could be created exactly the way I have made it up.

  Were I to posit in this new world the least thing that is obscure, it could happen that, within that obscurity, there might be some hidden contradiction I had not perceived, and thus that, without thinking, I might suppose something impossible. Instead, being able to imagine distinctly everything I am positing there, it is certain that, even if there be no such thing in the old world, God can nevertheless create it in a new one; for it is certain that He can create everything we can imagine.30

  CHAPTER SEVEN On the Laws of Nature of this New World

  But I do not want to defer any longer from telling you by what means nature alone could untangle the confusion of the chaos of which I have been speaking, and what the laws of nature are that God has imposed on her.

  Know, then, first that by “nature” I do not here mean some deity or other sort of imaginary power. Rather, I use that word to signify matter itself, insofar as I consider it taken together with all the qualities that I have attributed to it, and under the condition that God continues to preserve it in the same way that He created it. For from that alone (i.e. that He continues thus to preserve it) it follows of necessity that there may be many changes in its parts that cannot, it seems to me, be properly attributed to the action of God (because that action does not change) and hence are to be attributed to nature. The rules according to which these changes take place I call the “laws of nature.”

  To understand this better, recall that, among the qualities of matter, we have supposed that its parts have had diverse motions since the beginnin
g when they were created, and furthermore that they all touch one another on all sides, without there being any void in between. Whence it follows of necessity that from then on, in beginning to move, they also began to change and diversify their motions by colliding with one another. Thus, if God preserves them thereafter in the same way that He created them, He does not preserve them in the same state. That is to say, with God always acting in the same way and consequently always producing the same effect in substance, there occur, as by accident, many diversities in that effect. And it is easy to believe that God, who, as everyone must know, is immutable, always acts in the same way. Without, however, involving myself any further in these metaphysical considerations, I will set out here two or three of the principal rules according to which one must think God to cause the nature of this new world to act and which will suffice, I believe, for you to know all the others.31

  The first is that each individual part of matter always continues to remain in the same state unless collision with others constrains it to change that state. That is to say, if the part has some size, it will never become smaller unless others divide it; if it is round or square, it will never change that shape without others forcing it to do so; if it is stopped in some place, it will never depart from that place unless others chase it away; and if it has once begun to move, it will always continue with an equal force until others stop or retard it.