Res extensa

“...by a body I understand whatever has a determinable shape and a definable location and can occupy a space in such a way as to exclude any other body...”

I’m unclear whether extended things are extended in the three spatial dimensions essentially, and extended temporally (duration through time) only accidentally, or if temporal extension is also essential.

From this early definition of extension it appears that only spatial extension defines bodies, but earlier Descartes mentions duration through time as among the ‘primary qualities’ or elements of real objects.

More on the cogito

“So after considering everything very thoroughly, I must finally conclude that this proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind.”

I often ask students why Descartes didn’t just write the famous version of this argument: I think, therefore, I am. It’s actually kind of puzzling. The star of the argument in the version he actually presents here is a proposition, not a self, not a rational being, not a thinking thing, none of usual Cartesian suspects.

The argument is based on a modal property of an abstract object: that some proposition has some modal status such that it is necessarily true on the occasions of its uttering or entertaining in thought. And implicit in the claim is that that abstract object has a peculiar referential property: that it refers to its entertainer/utterer, and that without failure.

In an earlier post I wondered about the tensions between the semantic and the pragmatic in the argument. This other tension I’m noticing is between the content of a proposition, and the object that causes its reference to succeed.

A further wrinkle: the object that causes it to succeed does so categorically (that is, anything/anyone that utters ‘I am, I exist’ must exist, regardless of how the rest of the universe is configured). Referential success is thus a priori. But then how to square that with the contingent character of the cogito: namely, that it is necessarily true on this or that occasion, but not timelessly?

I need to untangle the notion of essence from reference, which I can’t do right now. But this anticipates meditation 5, and Kripke. More later.

More on elements

“For even when painters try to create sirens and satyrs with the most extraordinary bodies, they cannot give them natures which are new in all respects; they simply jumble up the limbs of different animals. Or if perhaps they manage to think up something so new that nothing remotely similar has ever been seen before—something which is therefore completely fictitious and unreal—at least the colours used in the composition must be real. By similar reasoning, although these general kinds of things—eyes, head, hands and so on—could be imaginary, it must at least be admitted that certain other even simpler and more universal things are real. These are as it were the real colours from which we form all the images of things, whether true or false, that occur in our thought.”

This includes, says Descartes, extension, shape, quantity, place, time of duration. Is this a first stab at primary qualities?

Does Descartes mean that one begins, even in imagination, with these elements that are the same throughout the natural world? Is it a prior constraint on our thought about the natural world? Or does he mean that nature itself has these constraints, that objects already have built into them these qualities? The first gloss is the Kantian, of course, the second, Lockean.

Or does such a distinction not make sense to ask of Descartes?

The puzzle gets trickier when, in the second meditation, Descartes supposes that, among other things, “[b]ody, shape, extension, movement and place are chimeras.” Why don’t those ‘chimeras’ resist doubt in the thought experiment, if they are universal, simple, and thus real?

I never realized this before: if Descartes maintains a distinction between primary and secondary qualities, or elements and arrangements of elements, does that undermine his solipsism? Wouldn’t the existence of primary qualities be assured, even if the secondaries were doubtful?

Maybe this is how Locke and Kant read him. I never thought about it in these terms before.

The dream argument

“...I see plainly that there are never any sure signs by means of which being awake can be distinguished from being asleep.”

How meta is this argument?

I always thought the argument was supposed to be that the information is the same in both cases—the waking state and the sleeping state—and thus we cannot tell from that information whether an inference to the corresponding reality of the objects represented by the information can be successfully made.

But if that is so, the objection can be pressed that if the information is sensory, then the inference is implied (if the senses work), and if it is not, the inference fails. And in the waking state the information is sensory, while in the dream state it is not—it is imaginary.

Descartes can forestall this objection by insisting that the distinction between imaginary information and sensory information cannot be detected by the conscious mind that is the subject of the mental states in question. But if that were so, then how could the mind ever tell the difference between imagination and the intellect? Wouldn’t it follow that we were always subject to illusions and imagined things all the time? That seems an extreme overreach.

If the argument is pitched at a more meta level, he can shimmy out of this. It is not that the nature of the information itself is opaque to us, but that we must rely on some other information (some meta-, secondary information) to sort out this otherwise opaque, primary information. So, if we have red patch information:

there is a red patch in my visual field right now

then we need information about that information to tell us whether it is imaginary or sensory.

Either:

there is a red patch in my visual field right now that is being delivered by my functioning, wide awake eyes

or else:

there is a red patch in my visual field right now that is being delivered by my overactive imagination.

If the dream argument is supposed to go that high up, Descartes avoids my earlier worry, but then it looks puzzling in a different way. The meta-information move makes it seem as though the higher-order thoughts are about the lower-order thoughts—perhaps that is right—but this seems at odds with Descartes’s view that the intellect, when it knows what is true, takes as its object ideas that are ‘clear and distinct’. In fact, that is how the intellect knows it is judging truly—the clear and distinct criteria are met. But it seems completely at odds with this to think that the clear and distinct things that the intellect knows are less-sure perceptual ideas about red patches and the like. Those are the very paradigm of non-clear and non-distinct ideas. Hence it seems strange to think that Descartes sees the intellect as piggy-backing on perception this way.

I might not figure this out until meditation 6.

Can science be science without its math?

I have to say that I've always been a little confused by Descartes' distinction between the 'composite' sciences (physics, astronomy, medicine) and the 'simplest and most general' sciences (arithmetic, geometry, and 'other subjects of this kind').

He clearly wants to make the point that the composite sciences assemble elements of truth and fact--that is, small things that are true, I guess--while the simple-general sciences furnish the list of those elements in the first place. An inelegant paraphrase on my part, I realize, but good enough for now.

But that seems to come apart to the extent that the composite sciences include within them, as proper parts, the simple-general sciences. For instance, what is physics, if you 'remove' the calculus? For that matter, what is biology (surely a composite science) without the systematic description of rates of change of physical factors inherent in ions and all the rest, etc., that characterize the conduction of a nerve signal along an axon? Can science be science without its math?

The free mind

The idea of a free mind motivates much of the Meditations, but in a way that's hard to spell out exactly.

One can say (as I have explained it to students) that freedom of mind can only be possible if the mind is metaphysically independent of the body, thus ensuring that it's undetermined by physical laws. But I'm starting to think it's more profound than that. The cogito argument urges that the proposition I am I exist is necessarily true when it is spoken/thought. It's not that the proposition is true, but that it is necessarily true, implying that the freedom of the mind is not just a causal freedom (the opposite of being determined), but a kind of modal freedom. Perhaps: the mind has a different modal status than the body.

Hmm. I'm not sure how to spell this out either.

The rationalist’s pronoun

The first-person pronoun is especially important to the rationalist, of course, since it’s the tag in the language that tracks with the locus of the reasoning faculty. It’s a code that marks the existence of a code-maker, a symbol that symbolizes the symbolizer. (Okay, enough of that.)

It is often remarked upon that Descartes writes in the first-person, and this would presumably be the reason. (How else could the cogito be expressed?) But there are two interesting consequences of this. The first is due to the kind of reason I hinted at in the previous post. If the cogito stands at the interface between the pragmatic and the semantic, then the linguistic puzzle it presents is directly due to the occurrence of the first-person pronoun. (I suppose that’s often pointed out.) The second lends weight to my interpretive hypothesis that the Discourse reads like a slave narrative: not only does the work establish, through the conventions of narrative, the authenticity of the author, but it does so non-detachably. Its pivotal moment occurs right here, at the cogito argument, an argument that cannot (without loss of meaning) be rendered in anything but the first person—precisely what one would expect of a slave narrative.