Monday, March 22, 2010

The Cogito

Is Descartes' Cogito argument indubitably sound? Descartes tells us, basically:

  1. I think.
  2. Therefore, I am.
But I can doubt the proposition expressed by (1). For the proposition expressed by (1) is that Descartes exists, and I can doubt that. Now what I can't doubt is that I think. So the Meditations are different from a traditional philosophy book in that they do not give an argument that is supposed to convince the reader. Rather, they give an argument of which a homophone is supposed to convince the reader—the reader is expected to say to herself: "I think. Therefore, I am."

Instead of providing us with an argument against scepticism, Descartes shows us by example how we should argue our way out. In fact, there is no argument that he could give that we could use. Suppose Descartes said:

  1. You think.
  2. Therefore, you are.
But I could doubt that the person Descartes refers to with "you" exists. For instance, I could doubt that Descartes meant for me to read his book. Likewise, if the Descartes said "the reader", since I could doubt that I am reading, as I could simply be dreaming that I am reading; besides "the reader" is not of unambiguous reference.

I suppose this is why Descartes called these thoughts meditations.


Brandon said...

I forget the exact passage, but Descartes somewhere in the Replies to the Objections denies that it is an argument at all; despite the verbal form, the two claims are not related as premise and conclusion in the intellect. But I think you're basically right; Descartes is giving an example we are supposed to follow rather than an argument.

Doug Benscoter said...

Wouldn't the experience of reading count as an incorrigible belief? "I am being appeared to as though I am reading" may be more technically correct. In order to doubt this or some other proposition (e.g. "I am being appeared to redly"), we first have to have the experience. In other words, the external world can be doubted, but not the experience of the external world.

I agree, though, with the gist of your entry.

Apolonio said...

I don't know, it seems like an argument to me. I think, therefore I am could be translated as:

If I think, I exist. I think, therefore I exist. Of course since the sentence is an indexical, it will depend on the context and utterance. But it shows that if "I think" is true, then the "I" must exist.

Anyway, what do you think of Williamson's argument in "Necessary Existents" (as well as Plantinga's argument).

Necessarily, if I do not exist, the proposition that I do not exist is true.

If the proposition that I do not exist is true, that proposition exists.

And so on....

Apolonio said...

since the sentence contains* an indexical.

enigMan said...

I agree with the gist of that.

You could take 'you' not to refer to yourself; but then again, you might take it to refer to yourself. Indeed, you might take 'I' in the Cogito to refer to yourself precisely because you take the Cogito to be an argument. Since it is an argument, one might think, I shall take "I think" to name the proposition that I would most naturally describe as that I think.

Is there any 'argument' that could not be interpreted in some pedantically correct way so that it was not an argument? But even if, as I suspect, not, surely that does that mean that there are no arguments; and so surely the Cogito is (since it can be) an argument. And when it is an argument, it is indubitably sound, I think.

Alexander R Pruss said...

Well, Descartes' argument was presumably about himself, and that argument isn't indubitable to us, because we can doubt whether Descartes thought. If his argument was about us, it wasn't indubitable to him. :-) So what we have is an argument schema, which we are urged to plug ourselves into.

As for the necessary existents argument, I think anybody who doesn't believe all propositions exist necessarily should deny the schema:
Necessarily: if p, then p is true.

Doug Benscoter said...

enigMan, "And when it is an argument, it is indubitably sound, I think." Therefore, I am. :)

enigMan said...

Hmm... but then what arguments are not 'really' argument schemas? One has to plug in one's own interpretation of the words on the page, in order to understand any argument. One may then think about it and say that the argument is really the one the author intended, but the only grasp we have of that is what we think the author intended. And when I read the Cartesian "I think" I think that Descartes intended me to interpret that 'I' as me, at least some of the time. His argument was indubitably sound for him, with his 'I' as him, as one can see by examining one's interpretation of his argument in which the written 'I' is one. I'm not sure that the definite concept of a schema is the most apposite concept here. When we read stories we often partially identify with the author (in a way only partially different to the way in which we dream), and such partial identifications are part of how we learn the meanings of words, of how anything is understood by us. The argument Descartes shows us is the argument he gave himself, but while it contains an indexical, does it really become a different argument when we understand it?

enigMan said...

To put it another way, the Cartesian Cogito is certainly valid, and there are a couple of reasons why its premise is indubitably true.

Firstly, your problem arises because we are taking the speaker-meaning, but then "I think" only has meaning if there is someone thinking. So it is either meaningless or true. And if it is meaningless then there is nothing to doubt.

Secondly, the argument appears in a book, and so either the 'speaker' is fictional or else he is real. But in the former case the fictional 'speaker' certainly is fictionally thinking (and the valid argument just shows that he is fictional).

Doug Benscoter said...

Yeah, I agree.

Descartes: "I think . . ." can be interpreted as

"Descartes thinks, therefore he is."

However, given that Descartes was writing a meditation and talking to himself, essentially, the reader is most likely encouraged to simply repeat the "I think" self-referentially. So, whenever I read his Meditations on First Philosophy, I am reading it as if I am the one making the reflection. The cogito ergo sum is, therefore, indubitable to me whenever I reflect upon it, but it won't be indubitable to anyone else that I exist. The same goes for anyone else meditating on it.

Jason Dulle said...

I have heard of some who argue that Descartes' cogito depends on a logical fallacy: begging the question. The question is whether there exists a personal subject, “I.” And yet “I” is smuggled into the second premise of the argument (I agree with Apolonio that even if Descartes did not mean for it to be an argument, it follows the form of an argument).

That is question-begging, for it assumes there is an I to experience the act of thinking, and then concludes that there is an I who thinks.

I am conflicted about this. On the one hand, this seems reasonable to me. Descartes reasoning does seem to beg the question. On the other hand, Descartes argument seems valid: the ability to contemplate one’s existence requires that they exist.

If Descartes did beg the question, invalidating his argument, then it seems there is no non-question-begging argument that could indubitably prove I exist. Of course, this does not mean I do not exist. I do, and I know I do. It simply means we can’t demonstrate how we know this, other than an appeal to basic intuition.

Jason Dulle said...

No takers? I am really hoping someone can help me solve this problem. Thanks!