Originally posted by DoctorScribbles
You are confused about the propositional content of his statement.
He is in fact saying that thinking is dependenet upon existence, that is, that existence is a necessary condition for thinking, hence the correctly stated implication. A claim of the form "A implies B" expresses that A is logically dependent upon B, or that B is a necessary condi ...[text shortened]... ropositionally equivalent to "I am, therefore I think" for reasons analogous to those above.
Yes, perhaps I should rephrase; my intention was not to show the falsity of his statement, but rather his reasoning process surrounding the creation of the 'cogito'. Descartes was trying to say what he could have no doubt about with reference to existence. If existence is only indubitable to him by the recognition of self in a thinking process, then the use of 'I' cannot preceed the presence of the thinking process since the use of 'I' implies existence. To say 'I
think' presupposes the presence of the very conditions necessary to remove the doubt against 'I' in relation to existence. Of course he's a thinking thing and existence is a necessary condition of thought, but it is clear from reading the meditations that the 'cogito' is his attempt to prove existence, which it does not. Semantics? Maybe, but in the search for what one can have surety about in relation to existence, one must first prove existence before one can see if an existing thing can think.
Something like this maybe (I'm not very good at things like this to be honest)?
There is an I, there is a thinking thing, there is existence, such that I think therefore I exist. This implies that existence is known and that I is a part of that, the very thing Descartes was doubting and trying to show surety about.
If I've failed to explain what I mean I apologise, perhaps we could discuss this by PM, I find it greatly interesting, but I am pretty crap at formal logic.
Also worth mentioning, when Descartes was meditating on the nature of his own existence, formal logic and its application, particularly to language, was not a process he had at his disposal and whilst he may have been the first philosopher to use algebraic methods for analysis, what you and I call logic is far removed. He certainly would not have expressed his thought in such a formal way, considering that the Meditations are a greatly discussive collection.