For Descartes, matter was extension - res extensa - an extended thing. That was his simple definition of material stuff. And space was the relations between extensions. Descartes only had three things in his ontology. Material, thought, and God.Newton thought that besides bodies there was space, and things were located in the space. But according to Descartes, extension -that is to say, space- constituted bodies. In which sense was space relational for Descartes , Rhubarb?
But which relations would those be? Do you think that for Descartes those relations were objective in the same sense in which his candle and his table were objective to him? Or that they were ideally objective in the kantian sense?For Descartes, matter was extension - res extensa - an extended thing. That was his simple definition of material stuff. And space was the relations between extensions. Descartes only had three things in his ontology. Material, thought, and God.
As opposed to Newton and other substantivalists who, like you said, reckoned that space was a ‘thing’ of sorts or substance-like, that it existed in a real way in their ontology.
Space was a relation of distances, for Descartes, and if I recall correctly it utilized his coordinate system. Space was measurement relations between the res extensa that was littered about. The physical bodies were simply extension. If memory serves, this wasn’t an ‘objective’ system. You can “draw your axis anywhere.” His mechanics was based on this, too. Descartes didn’t postulate ‘space’ in his ontology. It existed only as relations between extended bodies. Whereas, like you said, Newton did include ‘space’ in his ontology. Substantivalists thought that space was ‘substance-like’ and acted as a container to hold matter. (Of course, this is a very very very broad characterization)But which relations would those be? Do you think that for Descartes those relations were objective in the same sense in which his candle and his table were objective to him? Or that they were ideally objective in the kantian sense?
For Descartes, matter was not the same as it was for Newton, but pure extension; and extension was not an a priori intuition, but something which existed in itself. Descartes did not need to think on an empty space which could be filled with matter, because he did not admit the possibility of vacuum. So, space and res extensa were not different to him.
Look how even for Newton those relations of distances were possible; but it does not mean that space was just a system of relations to him. To be extended means, as it meant to Descartes as well, to be spatial. What you seem to be saying is that for Descartes each body was an space by itself, but as I have said, to him there was no possible separation between bodies.Space was a relation of distances, for Descartes, and if I recall correctly it utilized his coordinate system. Space was measurement relations between the res extensa that was littered about. The physical bodies were simply extension. If memory serves, this wasn’t an ‘objective’ system. You can “draw your axis anywhere.” His mechanics was based on this, too. Descartes didn’t postulate ‘space’ in his ontology. It existed only as relations between extended bodies. Whereas, like you said, Newton did include ‘space’ in his ontology. Substantivalists thought that space was ‘substance-like’ and acted as a container to hold matter. (Of course, this is a very very very broad characterization)
Eh? I mean, there ARE relations of distances for Newton. But those relations aren’t what space ‘is’. I mean, here’s taken from Wikipedia - “In metaphysics, extension is, roughly speaking, the property of “taking up space”. René Descartes defines extension as the property of existing in more than one dimension. For Descartes, the primary characteristic of matter is extension.” Extension is the matter itself. The space is just the math in between the matter. The extension that is matter can be in the measurements of space, but it isn’t ‘space itself’. For Descartes, space isn’t a thing. It has no existential property. But extension is the length, width, and depth of a corporeal object. And then if you and I were standing together, our bodies are extension. But the ‘space’ between us is just math. It isn’t a ‘thing’ as Newton would say.Look how even for Newton those relations of distances were possible; but it does not mean that space was just a system of relations to him. To be extended means, as it meant to Descartes as well, to be spatial. What you seem to be saying is that for Descartes each body was an space by itself, but as I have said, to him there was no possible separation between bodies.
The Wikipedia sounds like Newtonian doctrine, but if it was a Leibnizian who was in charge of the article, it would say a different thing. I don’t think it is a good reference, Rhubarb.Eh? I mean, there ARE relations of distances for Newton. But those relations aren’t what space ‘is’. I mean, here’s taken from Wikipedia - “In metaphysics, extension is, roughly speaking, the property of “taking up space”. René Descartes defines extension as the property of existing in more than one dimension. For Descartes, the primary characteristic of matter is extension.” Extension is the matter itself. The space is just the math in between the matter. The extension that is matter can be in the measurements of space, but it isn’t ‘space itself’. For Descartes, space isn’t a thing. It has no existential property. But extension is the length, width, and depth of a corporeal object. And then if you and I were standing together, our bodies are extension. But the ‘space’ between us is just math. It isn’t a ‘thing’ as Newton would say.
You can find the same thing on the SEP (“that the essence of matter is extension”), and other resources. I promise you, that’s the correct characterization of Descartes’ conception of material bodies. If memory serves, it can be found in the Principles.The Wikipedia sounds like Newtonian doctrine, but if it was a Leibnizian who was in charge of the article, it would say a different thing. I don’t think it is a good reference, Rhubarb.
So, there were relations of distances for Newton, but those relations were not space to him. Space was something else. What was it?
And for Descartes, space wasn’t a thing, but just the math, that is to say, a system of relations that could be established (but not necessarily) by each one of us. And the element which was at the basis of those relations was for him the continuity of the res extensa (because -I repeat-, there was no vacuum for him). Is this what you are saying?
Of course! There is no doubt in my mind that for Descartes extension constituted the nature of bodies. I guess the question for you would be if there was a real difference between “extension” and “space” for Descartes. I suppose that reading Descartes might be confusing at times in this respect, due to the way in which he uses both terms. And he was quite aware of this source of confusion, though I think he never thought he could be the cause of it. Rather it was the conventional use of the terms. However, he clarifies what he thinks about space/extension in texts like the following (Part 2: 10-12… of the Principles of philosophy: "What space or internal place is…):You can find the same thing on the SEP (“that the essence of matter is extension”), and other resources. I promise you, that’s the correct characterization of Descartes’ conception of material bodies. If memory serves, it can be found in the Principles.
Newton believed in ‘absolute space’ - that space was it’s own thing. I don’t know what he thought space was ‘made of’, but in his bucket experiments (sometimes called bucket argument) he thought he showed that rotational motion can’t be simply relational motion and therefore an absolute space that exists is necessary.
And yeah… That looks correct to me what you said about Descartes, as I remember and what I’ve read to refresh myself.
I see what you’re saying. Yes. We’re talking past one another. I’m not saying that Descartes’ space doesn’t have ‘extension’ in a sense. But as you pointed out: “We attribute a generic unity to the extension of the space [of a body], so that when the body which fills the space has been changed, the extension of the space itself is not considered to have been changed or transported but to remain one and the same; as long as it remains of the same size and shape and maintains the same situation among certain external bodies by means of which we specify that space.” (Pr II 10F) So for Descartes, ‘space’ is an abstraction from ‘body.’ It’s extension with the… uh. Matter abstracted away. Leaving measurement. This is what Descartes uses to constitute his relationist theory of motion - like the relationist theory that Newton argues against. (Through Clarke in the Leibniz-Clarke Correspondence)Of course! There is no doubt in my mind that for Descartes extension constituted the nature of bodies. I guess the question for you would be if there was a real difference between “extension” and “space” for Descartes. I suppose that reading Descartes might be confusing at times in this respect, due to the way in which he uses both terms. And he was quite aware of this source of confusion, though I think he never thought he could be the cause of it. Rather it was the conventional use of the terms. However, he clarifies what he thinks about space/extension in texts like the following (Part 2: 10-12… of the Principles of philosophy: "What space or internal place is…):
There is no real distinction between •space or internal place and •the corporeal substance contained in it; they differ only in how we usually think of them. In reality (·in contrast to ‘In our thought…’·) the extension in length, breadth and depth that constitutes a space is exactly the same as the extension that constitutes a body. Our two ways of thinking about this extension differ as follows. When we are thinking of it as a body, we regard the extension as something particular that moves when the body moves. When we are thinking of this extension as ·a portion of· space, we attribute to the extension only a generic unity, i.e. we think of it not as one individual •thing but as one •set of specifications that might apply first to one thing and then to another. This thought of one body moving out of and another moving into the very same extension requires that the extension in question retains the same size and shape and keeps the same position relative to certain external bodies that we use to determine the space in question.
It is easy for us to see that the extension that constitutes the nature of a body is exactly the same as the extension that constitutes the nature of a space. They don’t differ any more than the nature of a genus or species differs from the nature of an individual ·belonging to that species or genus·. Let us attend to the idea we have of a pebble, leaving out everything we know to be non-essential to the nature of body: we will first exclude hardness, because if the pebble is melted or pulverized it will stop being hard but will still be a body; then we’ll exclude color, because we have often seen stones so transparent that they have no color. Next we’ll exclude weight, because although fire is extremely light it is still thought of as being corporeal; and finally we will exclude cold and heat and all other such qualities, either because they aren’t thought of as being in the stone, or because changes in them aren’t thought to deprive the pebble of its bodily nature. After all these exclusions we’ll find that nothing remains in the idea of the pebble except its being something extended in length, breadth and depth. But that’s just what is comprised in the idea of a space—and not merely a space full of bodies but even one that is called ‘empty’…
Now, I think we can ask again: Was space a system of relations for Descartes? And in view of the text above, this question would be equivalent to this other: Were bodies systems of relations for Descartes? And I think the answer is clearly “No”.
So, while for Newton space was something independent of bodies, for Descartes body and space were exactly the same thing.
I think, Rhubarb, that you only have to pay more attention to the quote I brought in my previous post. Specifically this part: “There is no real distinction between •space or internal place and •the corporeal substance contained in it; they differ only in how we usually think of them”. The rest (and you can continue reading the rest of the chapter of the Principles) is an explanation of this words.I see what you’re saying. Yes. We’re talking past one another. I’m not saying that Descartes’ space doesn’t have ‘extension’ in a sense. But as you pointed out: “We attribute a generic unity to the extension of the space [of a body], so that when the body which fills the space has been changed, the extension of the space itself is not considered to have been changed or transported but to remain one and the same; as long as it remains of the same size and shape and maintains the same situation among certain external bodies by means of which we specify that space.” (Pr II 10F) So for Descartes, ‘space’ is an abstraction from ‘body.’ It’s extension with the… uh. Matter abstracted away. Leaving measurement. This is what Descartes uses to constitute his relationist theory of motion - like the relationist theory that Newton argues against. (Through Clarke in the Leibniz-Clarke Correspondence)
By ideal, do you mean like Dynamism?I think, Rhubarb, that you only have to pay more attention to the quote I brought in my previous post. Specifically this part: “There is no real distinction between •space or internal place and •the corporeal substance contained in it; they differ only in how we usually think of them”. The rest (and you can continue reading the rest of the chapter of the Principles) is an explanation of this words.
Now, though motion certainly involves space, it is not space; and someone who understands motion in a relational way (like Descartes, certainly), does not have to understand space as a system of relations. In Descartes philosophy you cannot abstract space from matter, because for him space is what constitutes matter.
And the idea that Descartes’ notion of space is comparable to the corresponding Leibnizian notion is really unfortunate. In a letter to de Volder, Leibniz wrote this: “One of the main errors of the Cartesians is that they conceived extension as primary and absolute, and as something which constitutes substance”. For Leibniz, on the other hand, space was not real, but ideal.
No, it means that, for Leibniz, space is not independent of your mind.By ideal, do you mean like Dynamism?
Relative motion? If you are on earth, you can consider yourself fixed and see the moon as moving around you. But if you are on the moon, you can consider yourself fixed and see everything else moving around you.So what is Newtonian relativity?
They are comparable, in that they can be compared. You’re right, they’re not the same. I didn’t mean to claim they were. Descartes’ and Leibniz’ conceptions of space are both anti-absolutist was what I meant.idea that Descartes’ notion of space is comparable to the corresponding Leibnizian notion is really unfortunate. In a letter to de Volder, Leibniz wrote this: “One of the main errors of the Cartesians is that they conceived extension as primary and absolute, and as something which constitutes substance”. For Leibniz, on the other hand, space was not real, but ideal.