The Truth About Matter

by Rene Descartes Icon

3 minutes • 620 words

Table of contents

4. The nature of body consists not in weight hardness, colour and the like, but in extension alone*

Compressed Versus Decompressed Bodies*

4. The nature of body consists not in weight hardness, colour and the like, but in extension alone*

Superphysics Note

Descartes reiterates that the nature of matter is it occupying metaphysical space. From now, we will replace ’extension’ with ‘metaphysical space’ to distinguish it from ‘space’ as physical space

The nature of matter or body in general does not consist in anything sensory.

The nature of matter or body is in it being an [aethereal] substance extended in length, width, and height.

Hardness is just the ability of hard bodies to resist the motion of our hands on coming into contact with them.

But if all bodies moved away from our hands whenever we tried to touch them, then we would never experience hardness.

Yet those bodies would still be bodies to us.

Therefore, the nature of bodies does not include hardness.

In the same way, weight, colour, and all the other qualities of this sort, which are perceived in corporeal matter, can be removed from matter entirely.

It follows that the nature of body depends on none of these.

Compressed Versus Decompressed Bodies*

Superphysics Note

We replace rarefaction with ‘decompression’ and condensation with ‘compression’. This is to better associate with ‘pressure’ from the Negative Force.

5. The nature of body as extension is obscured by the opinions on decompression and vacuum.

Two reasons prevent the acceptance of the truth that the nature of body consists in metaphysical space alone.

Some bodies can become very much decompressed and very much compressed

When decompressed, bodies have greater metaphysical space than when compressed.

Some even have subtilized to the point that they make a distinction:

between the substance of body and its quantity
between quantity itself and metaphysical space.

We think of extension or metaphysical space as length, width, and height.

People think that void is merely a negation of space.

6. How does decompression take place?

If we watch our own thoughts, we will discover that the decompression and compression of an idea-body is merely a change of shape in the decompressed or compressed body.

In other words:

decompressed bodies have more gaps between their particles

compressed or dense bodies, on the other hand, have less or no gaps between their particles.

Space versus Metaphysical Space — The idea of the object takes up no physical space

The body, however, does not have less metaphysical space when compressed than when its particles occupy more physical space.

The idea-body of an object does not expand when it is decompressed by the mind. Instead, other idea-bodies fill in those gaps that are created by the decompression.

A sponge full of water is different from a dry sponge because the wet sponge has wider pores.

This makes its body more diffused over a larger physical space.
But this does not mean that each sponge-particle has greater metaphysical space when wet than when dry

7. Decompression should only be thought in that way

Some say that the decompression of an idea-body is the result of the augmentation of the quantity of body.

I say no, and explain that this augmentation is an example of the sponge.

When air or water is decompressed, we do not see:

any of its pores that become large, or
any new body that is added to occupy them.

But we still suppose that there is something unintelligible happening, so that we can explain the decompression of bodies.

This is better than inventing the concept of a new body that fills the pores or distances between the particles which are increased in physical size.

Any other explanation will create a contradiction.

If we say that a new body filled up that metaphysical space, then it means that there suddenly is something that did not exist before.