I think therefore i am.....

Great Debates
141

The asserting exists, but there’s no asserter in the asserting. There’s just asserting.

About Russell I don’t know. Look up his, “Theory of types”.

But in a incomplete nutshell to this issue: A class is not a member of that class. Hence the class of self experiences is not itself a self experience. Which I understand as: I cannot experience myself experiencing.

Russell’s Paradox:

http://www.utm.edu/research/iep/p/par-russ.htm

That’s the paradox, there’s no his own. There’s no owner of the thinking/asserting.

142

starting with a clean slate is not how descartes approached the problem. but neither is his approach a proof of his existence.

his approach is reminiscent of one used to gain a set of axioms for logic. at some point, the concept can no longer be reduced without becoming meaningless, and there you have a set of things which must be taken as granted. that “i exist”, i take as granted, for what could i hope to say about anything if i didn’t?

i don’t know whether descartes wished his “cogito ergo sum” to be accepted as proof that he exists, or rather as proof that without considering himself to exist, he could not speak meaningfully on the topic. it doesn’t seem right to have an axiom with “therefore” in it. perhaps if he were speaking mathematically, he would’ve said:

let E(x) be “there exists x”.

  1. E(I, x), such that I thinks x, for some x.

that seems like a reasonable assumption. whether or not descartes meant it as an assumption is not at all clear to me.

143

Descartes explicitly wanted it to prove the self.

begbert, quite frankly Descartes didn’t discount everything or he would not have added anything to our concepts, as all that remained was thought. Specifically, what remained was the grammar of “to think” (your decidedly metaphysical insistence that thought implies a thinker, which it may, but only because of how we use the word “thought”—i.e. - there’s nothing special here), and the notion of self, which were then trivially united in the statement we deal with.

You noted twice that we have an assumption that he could not “disprove the assumption of his own existence”, which I dare say is painfully obvious[sup]†[/sup]. Assumptions are only disproven given (1) the assumption of the law of non-contradiction and (2) the derivation of a contradiction. So I am not particularly stunned by his inability to doubt his own existence through a rationally eliminative approach.

Furthermore, even granting these “leftover” assumptions (however hidden), the most I think that could be said, charitably even, is that he discovered thought and renamed it “self”. The “distinction without any difference” point is one I will return to again and again, and after having reread the second meditation I feel more convinced than before.

For either he discovered self, or he discovered thought. If he discovered self, then he didn’t remove everything but his own doubts; if he discovered thought, then he didn’t do anything other than rename ‘thought’ as “self”—and this latter is hardly the point of the second meditation. Indeed, given his own outline,

†[sub]It matters little where assumptions come from, other than they aren’t justified (else they wouldn’t be assumptions). Your note that this particular one comes from the real world is unnecessarily hasty as it is just that world that we’re supposed to be doubting.[/sub]

144

So many viewpoints, so little time! Well, once more into it…

Ramanujan:
I don’t understand E(i, x); I thought E took one parameter.

Descartes actually considered his statment ‘cogito ergo sum’, or ‘cogito sum’ as he sometimes wrote it later, to be so brilliantly simple that it was fundamentally irrefutable. The fact is to be taken as axiomatic the way we take the law of gravity as axiomatic: we assume it to be the case, but not without evidience in its favor. (This is in contrast to axioms in formal logic or math, which are assumed to be true without justification. It’s probably not correct to call facts ‘axioms’ outside mathematical contexts.) Descartes didn’t consider this to be a discussion in formal logic; he was speaking of things on the order of irrefutable truths. He didn’t consider “cogito ergo sum” to be an assumption or an inference; he considered it to be fact.

You don’t assume ‘I exist’ because it enables you in saying other things; you conclude ‘I exist’ from the fact that, if you didn’t, you wouldn’t be able to conclude anything one way or the other. NOT that this is how Descartes would have presented it, but here’s logic again:

Define:
E(x) = x exists
P(x) = x is (mentally) doing a proof in formal logic

Premises:

  1. Ax.( ~E(x) -> ~P(x) )

  2. P(I)

  3. ~E(I) -> ~P(I)
    :. E(I)
    by modus tolens on 3 and 2, of course.

While any action would be sufficient to be P(x), Descartes considered ‘think’ to be stronger because, having already doubted all percievable existence, claims to be engaging in pyhysical are impossible to verify to onesself. He also defined thought rather loosely, so I believe my P(x) fits the definition.

Iamthat:
Russell did indeed consider Descartes’s argument to be weaker than Descartes’s maintined. But first, Russell’s Paradox is a different issue, according to that handy link you provided. According to him, classes can be members of themselves; it’s required for his paradox, which is about classifications, not existence. On to the issue: Descartes considered “I think” irrefutable; Russell did not. As has been otherwise brought up several times, Russell maintained that the ‘I’ was unmaintainable, and that what Descartes really had reduced to was ‘There are thoughts’. I don’t recall wether Russell carried his I-removal through the argument to make something similar to my ‘Arg 1’, or wether he sat on his hands and left it at the existence of thoughts alone.

My question, to those who wish to follow the ‘thoughts only’ perspective, is: why is it invalid for me to call my thoughts my own? The label ‘I’ is not meant to convey any implied meanings about the definition of ‘I’; You could think of ‘I’ as being defined as ‘the holder of these thoughts’, and not implying ‘human’, or ‘operating continuously’ or ‘having a material presence’.

erislover:
Oddly enough, proving existence was only supposed to be a lemma. What Descartes was gunning for (with far less success) was proving the necessary existence of God.

It is not recessary to ignore established grammar when disbelieveing everything; while you may disbelieve that your system of language or grammar has any external reality or meaning, you can still use it in reflection as much as you can still write out your thesis on ‘why paper doesn’t exist’ on paper. It is not necessary, when considering the possibility that there is no such thing as thought, to stop using thought yourself during your deliberations! The concept ‘to think’ has meaning; it requires an actor. It is in fact nonsensical to consider a thought without origin.

I am most likely guilty of first bringing the word ‘assumption’ into this discussion; it does not belong here. Assumptions only apply when we enter the framework of formal logic; while there; anything we consider axiomatic to our argument is called an ‘assumption’ or premisis, regardless of the amount of factual backing it has. No part of ‘cogito ergo sum’ should be considered an assumption in the common sense of the word.

Dunno why I’m jumping all over specific word use, but Descartes didn’t ‘discover’ anything. All the concepts, from ‘cogito’ to ‘sum’, with all the 'ergo’s in between, had been conceived of long before his time. And he did remove everything but his own doubts; but the fact that the doubts remained forced him to re-accept the existence of the mind containing the doubts. It’s all in that wonderful quote you provided:

This quote inarguably leads us to conclude that either 1) french doesn’t translate well, or 2) Descartes didn’t know how to express himself clearly. Read it very carefully; this is the long version of ‘cogito ergo sum’. [paraphrase] ‘In the second meditation, by doubting the existence of every object that can be even slightly doubted, the conscious mind will find that it itself must exist’ [/paraphrase]

Remember everybody, this is supposed to be simple :rolleyes:, and most of the terms and definitions are defined with the common uses of the words. (The exception is ‘sum’, or ‘am’; unlike usual assumptions of existence, no materiality or interactivity is implied. Merely simple existence.)

145

Not oddly at all, and in fact I deleted several paragraphs from my previous post outlining why such “universal doubt” was necessary for his program. Interesting you mention it as well. :slight_smile:

In which case you are not doubting everything, as I’ve indicated. The options seems simple to me: either he didn’t doubt everything he said he did, or he renamed “thought” as “self” and accomplished nothing.

And so long as you assume this to be true, I’m sure cogito ergo sum is a fantastic demonstration.

Yes, of course it is. A comment on the word “thought” and “to think” though, isn’t it?

Or he wasn’t saying what he thought he did, and didn’t see the holes in his own presentation. Descartes’s dualism has been under attack since he presented it; even his contemporaries were not pleased with it. Which has little to do with my argument, of course, I’m just saying.

Which make sense only in the world I just relieved myself of the burden of considering as real. The words, and their implications, go with it. If they don’t, I haven’t doubted everything and the “demonstration” is still quite tautological.

146

So, you’re not going to use existant words, thoughts, or concepts to discuss the sutuation? I grant that, if one refuses to think, then one can determine nothing. Also, if one categorically refuses to use words to describe their thoughts, then one can say nothing.

The task of doubting everything does not indicate that the argument should be made without using words, concepts, or thoughts. If you want to do that, you start by dismissing the notion of being able to doubt, ignore the implied contradiction, and sit around humming to yourself. This isn’t philosophy, however.

The point of philosophy is to bend our intelligence to the task of analyzing everything. I know of no philosopher who claimed that self-consistent usage of a term was out-of-bounds, in any argument. The important detail is that the definition remains consistent throughout.

(Aside)
Definitional consistency is an important detail, which does cause a potential problem with ‘cogito ergo sum’. I myself have been iterating over and over again that the ‘I’ is weakly asserted, causing ‘I am’ to be similarly weak. (Without identity information, yaddah yaddah yaddah.) This sounds like your stance as well, but it’s hard to be sure, with the rather sharp attacks on semantics that are going on. Out of curiousity, do you accept the underlying ‘proof’ of “I think”?

147

Of course we must do such a thing. But we must be super-careful to not bring real-world implications with us, and especially be on guard for drawing conclusions based on those.

Sometimes I wish it were. Might do some philosophers some good.

No, but a whole lot of them have been careful to try and remember that the self-consistent usage in question only “works” so long as it is being used so.

And I agree with this if by “weak” you mean “identical with thought”. :smiley:

No. As a personal matter, there is no consistent subject for sensation, and there is an axiomatically assumed subject for cognition.

148

Keep in mind that the term ‘thought’, as used in the argument, is brought in from the outside, and used in a metacognitive way to describe the doubts/whatever that are not reductively deniable. It is used to describe the reductively doubted thoughts; it is not one of the reductively doubted thoughts. Hence, there is no reason it should lose context.

Bother. I should have said; do you accept the underlying proof for ‘there is thought’? Answer at leisure.

No way; this time you’re putting forward a speculation as fact, and by the look of it, basing it on faulty logic:

  1. Having doubted everything but thoughts, I find only thoughts to be undoubtable.
    :. Thoughts are the only thing that exists. :dubious:
    :. The self must be a thought.

We’re claiming ignorance about things, not making definitive statements that they do not exist. Even when we have reduced ourselves until the only surety is that there are thoughts, that does not mean that we have disproved the existence of everything else.

Also, “self = identical with thought” implies “thought = identical with self”; or simply “thought = self”. We certainly don’t have enough information to conclude that there are no other thoughts than those that we identify with our ‘self’; besides being unfounded, your assumption seems to be a bit overenthusiastic.

If, at this point, you wish to ignore the intrinsic properties of what you have determined to exist (as encapsulated in our understanding of the term ‘thought’) that could be considered a personal problem, but you’re going to have a harder time selling your unsupported redefinition of the term ‘self’ over one that is slightly more consistent with the understood meanings of ‘thought’ and ‘self’.

149

First, I shall post Descartes own argument since it seems that is technically what we are debating, and not our interpretations or reworks of it. If it is the latter, then we’d best dispense with Descartes all together, quite quickly.

This is the smallest bit of the Second Meditation, the rest of which is devoted to finding out just what “I” is (as we’ve discussed, actually, I believe without denial). In fact, the undoubtable “I” is just what most of us have said it is: the solispistic thought. You note, begbert2,

It is not overenthusiastic, it is the purpose of the demonstration to doubt all that can be doubted, and to find that “I”—the thought of doubt—must be. This definitely gives us an analytic point of
thought <–> “I”.

Proof:
Suppose “I” was more than thought. Then there was either

  1. more we couldn’t doubt that we didn’t develop, or
  2. more we could doubt but didn’t.

[list=1][li]No further consideration is given to (1) in the second meditation except to restate his scepticism of sensation, though of course the third meditation is to prove the existence of god. While the following meditations are something to keep in mind in terms of this rationalist platform, Descartes does not attempt to equate other things that must exist necessarily with “I” so we should therefore presume that the second meditation is the whole of what can be doubted, and all that remains is “I”, which is the thought. Only if we consider the grammar of “to think”, that is, if we consider that there must be a thinker for thought, can we then assume our existence. In fact, we then have two “things” that exist, the thinker (that is, the one in such a meditation) and the thought (which, interestingly, is of the thinker). That this is not the point we reach then implies there is only one thing left: thought itself, which is “I” through redefinition.[/li]If there was more we could doubt but couldn’t, that would explain why we added to the concept of thought by positing an “I” (a self). But if this is the case, we may still doubt “I”. As this wasn’t done, either Descartes missed it or we have case 1. QED[/list=1]

150

begbert2

wrote:

The " I " as a holder or owner of these thoughts is just another thought.

" I " as in >my thoughts< implies something other then thoughts that owns them.

" I " can be doubted. The thoughts can be read like a book, in which there is no reader but only reading. And the thoughts as the contents of the book tell a story of a being (an alien) [ in a world] of which there is no identification to, or very little. I think that would be erislover’s #1

If another stream of thoughts could replace the current one, as in another tape, then there need not be any identification to any thought stream, of which comprises a self. There is no " I " but rather just a series of thoughts that appear to correspond to events/actions/ etc…and the observation of it.

151

Firstly, erislover, as to the unanswered questions in your helpful quote of Descartes:

Question 1 has the look of a rhetorical question to me, particularly since he answers it two sentences later: Q: “Am I so dependent on the body and the senses that without these I cannot exist?” Q: Obviously not, since he immidiately concludes that he does exist, without referring to the body or the senses.

Question 2 is a question of yours, regarding this passage: “But I had the persuasion that there was absolutely nothing in the world, that there was no sky and no earth, neither minds nor bodies; was I not, therefore, at the same time, persuaded that I did not exist? Far from it; I assuredly existed, since I was persuaded.” For the answer, read the entire passage. ‘Persuasion’ appears three times, including the one you claimed was a trick; the other two times refer to his ‘persuasion’ that nothing at all, perhaps including himself, existed. You misread the statement; “Far from it; I assuredly existed, since I was persuaded” does not mean ‘I was persuaded by some magic source that I existed’; it means 'By the persuasions I had done upon myself, I knew I existed. In short terms: ‘I doubted, therefore I am’. Sound familiar?

Staying within the quote for a moment, have a look at this phrase: “So that it must, in fine, be maintained, all things being maturely and carefully considered, that this proposition I am, I exist, is necessarily true each time it is expressed by me, or conceived in my mind.” The first half is Descartian verbosity, but the last bit has an interesting detail. He speaks of his reality being affirmed every time the proposition (that’s thought to us guys-be2) of that reality is expressed in his mind. Thoughts… in the mind.
Descartes by his own language states that there is a mind in which and by which the thoughts are being expressed.

Don’t try and tell me that Descartes was arguing against a thinker; he himself references it explicitly. If we’re going to go with Descartes’s own argument, and not our interpretations or reworks of it, then we’re talking about an I, which am, the existence of which is determined because that I thinks. Straight out of the quote, folks, deal with it.

Now, because saying ‘Descartes said so, so back down’ wouldn’t be any fun, I am going to point out the missed case in your argument:

Suppose “I” was more than thought. Then it was either

  1. something we couldn’t doubt that we didn’t develop,
  2. something we could doubt but didn’t, or
  3. something we already doubted but were forced to change our mind about.

The third case is exactly what happens: you point it out yourself.

“But I had the persuasion that there was absolutely nothing in the world, that there was no sky and no earth, neither minds nor bodies; was I not, therefore, at the same time, persuaded that I did not exist? Far from it; I assuredly existed, since I was persuaded.”

After considering the case of his own non-existence, he is forced to back down, since his own considerations were there to stand as proof otherwise. He am, because He think. QED

Thanks for the quote; I’ve been doing this from memory. It is nice to see a cite confirming my recollections, and to have something definitive (ie: not me) to point you to.
Iamthat… Descartes calls it, explicitly, “my mind”. The last two words of The Quote. If we’re still talking about Descartes, then to say that he’s talking about some metathought is absolutely incorrect; see the above explanation for how come he managed to get out of the back end of the argument with his mind intact and still have doubted everything inbetween. (May the doubtable diety shower blessings upon you, erislover; we’ve needed that quote for about the last hundred posts.)

Okay, open fire. :rolleyes: But make sure that it doesn’t contradict the Descartes!

152

begbert2

Ahh! That’s hasty… he concludes he exists without appealing to the external senses, this is true; however, that doesn’t mean he can or does exist without them. Remember, he doubts his body’s existence, and determine’s his mind’s existence, but at no point did we conclude that the mind can in fact exist without the body.

Right! Exactly. :smiley:

So… you see how he begs the question?

Exactly. So what was demonstrated?

153

Hi, erislover. Here’s my comment for the day…

What was demonstrated?
Well, it was at least demonstrated that Descartes thought he had proven his own existence, so I’m saved from being accused of making it all up from scratch. Believe you me, I consider that a good thing. :slight_smile:

I’m going to have to differ with you here; if he’s succeeded with the rest of the argument, then there’s nothing hasty about it. Descartes was of the opinion that he had demonstrated the mind’s existence without referring to the body or senses, making this a nice lead-in question. You don’t (yet:D) accept the proof, so of course you’re going to claim that this is in doubt as well. Let’s just move on, and let this resolve itself or not with the rest of the argument, shall we?

Nope. How about you present your case, and then I address it?

Two things, a mind and its existence. Time to bring out the big guns: More logic!! (Hey, you asked for it. You used a logical term: ‘beg the question’.) Maybe by keeping it symbolic we can put off the term-definition-denying to the end.

Definitions:
E(x): x exists
M(x): x has a mind capable of doubting
D(x, y): x doubts y

The logic:
A1: Ajk.( D(j, k) -> M(j) ) [assumed]
A2: D(I, M(I)) [assumed]

L3: D(I, M(I)) -> M(I) [by substituting I for j and M(I) for k in A1]
L4: M(I) [modus ponens on L3, A2]

From this we conclude that, because I have the capability to doubt that my mind exists, I can know that my mind exists. This is the ‘interesting’ part of Descartes’s argument. This is closely followed by the ‘disputed’ part of Descartes’s argument:

A5: Ap.( M(p) -> E(p) ) [assumed]
L6: M(I) -> E(I) [by substituting I for p in A5]
L7: E(I) [modus ponens on L6, L4]

This is ‘disputed’ because people say, “But I can’t prove that me and my limbs and zits and all exist just because I have a mind, which can manipulate thoughts!”. They’re right, of course, but they’re applying to much meaning to the word ‘exist’. I’ll get back to this.

And if there is anybody who is standing on the position that, because something was once doubted, it must always be doubted, I’m going to let them quietly retract their position with minimal further mocking. Ignorance can be abolished, even by Descartes before 1973! And of course in a logical argument, you doubt everything until you write it down.

Your question “What was demonstrated?” is, oddly enough, packaged with a quote about the A1-L4 part of the argument. This, I can deal with; the logical formulation (presented as such to try and stave off nit-pickiness and terminology-bashing) presents rather clearly the the doubt is sufficient to demonstrate that I bear the property of having a mind.

In order to dispute anything about this argument, you have to go for the premises:
A1: Ajk.( D(j, k) -> M(j) )
A2: D(I, M(I))
A5: Ap.( M(p) -> E(p) )

I’d be really surprised if you didn’t dispute A5, and A1 wouldn’t shock me either. However, we’re now down to terms and definitions. What universe are you in, that the fact that I am doubting doesn’t imply that I have the mental capacity to doubt? And as for the implication of existence, I’ve already stated that E(x) in this case means, “x exists enough to have a mind”. This isn’t an E that you can use to demonstrate that your svelte physical form exists; that would be B(x): “x has a body”. Talking about merely E, what universe are you in, that the fact that I have a mind doesn’t imply that I have enough existence to have a mind?

*(d’ya suppose he’s going to ask me where I got the right to ‘state’ the definition of E(x)?)

154

[list=a][li]E(x): x exists[/li]Existence is, at the very least, not a first-order property (if it is a property at all).

[li]M(x): x has a mind capable of doubting[/li]D(x, y): x doubts y
I don’t think that seperating these accomplishes anything.

[li]A1: Ajk.( D(j, k) -> M(j) )[/li]So are we saying doubts cause minds, or minds cause doubts? Also, what distinguishes a doubt from a mind (one of my sticking points, you might remember)?

[li]Summary of L4: From this we conclude that, because I have the capability to doubt that my mind exists, I can know that my mind exists.[/li]No you cannot. That’s what E(x) is for.

[li]I’m going to have to differ with you here; if he’s succeeded with the rest of the argument, then there’s nothing hasty about it. Descartes was of the opinion that he had demonstrated the mind’s existence without referring to the body or senses…[/li]Which is absolutely irrelevent to whether a mind needs a body or senses to exist, which is what you claimed. Suppose there is a body for my mind which must exist for my mind to exist as a matter of metaphysical fact. Note that if I were to accept Descartes argument, this assumption is never used. That does not mean it is false (your claim).

[li]What was demonstrated, I asked. The answer: Two things, a mind and its existence. Then we return to my previous objection laid out in my previous post: if from the evidence of one thing (the thought of doubt) we conclude the existence of two, then we either didn’t state some other things we didn’t doubt, or we didn’t doubt things we should have. One example would be your A1 which I call a comment on the grammar of “to think”. Another could be the psychologistic obviousness of A2 which is immediate knowledge, something I commented on much earlier with respect to memory which is appealed to in Descartes’s argument (most obviously in that ‘but I was persuaded’ commentary).[/li]
[li]I’d be really surprised if you didn’t dispute A5[/li]A5 is worthless to me because of the paradoxical implications of existence as a first-order property. Consider: “As to the paradox generated by negative existential propositions, it arises in this way. If ‘exists’ were a predicate, then its negation (‘does not exist’) should be a predicate also. But if ‘does not exist’ were a predicate, then in ‘Dragons do not exist’ it would be predicated of dragons only if dragons existed. And similarly for all negative existential propositions; paradoxically, if it is to be predicated at all, ‘does (do) not exist’ can be predicated only of what does exist.” Of course this discussion can lead us far astray of where we want to be.

[li]What universe are you in, that the fact that I am doubting doesn’t imply that I have the mental capacity to doubt?[/li]I am in the same universe as you, where when the proposition “I am doubting” is used to demonstrate “I have the mental capacity to doubt” that nothing has been demonstrated.

[li]that the fact that I have a mind doesn’t imply that I have enough existence to have a mind?[/li]What fact? It’s your conclusion. And your assumption. And thus, it is not a demonstration, either epistemologically or ontologically (and I think Descartes meant it more epistemologically but no matter, really, a circle is a circle).

[li]d’ya suppose he’s going to ask me where I got the right to ‘state’ the definition of E(x)?[/li]If I thought it would motivate the discussion I would, but I see no way of resolving existence as a property.
[/list=a]

My argument has been stated as concisely as possible (though there was one typing mistake in it the last time I posted it). Either we didn’t state everything we couldn’t doubt and thus could “get” more from “doubt is happening” than “doubt is happening”, or we didn’t doubt everything we could have, and any claim greater than “doubt is happening” is able to be doubted.

Note Descartes’s elegance “demonstration” relies, he thinks, only on the existence of doubt. But the demonstration of a doubter relies, obviously, on the implication of “doubts imply a doubter”, at least solipsitically. So we have at least two things that are beyond doubt. The metaphysical implication in the statement “doubts imply a doubter” or your A1 is doubtable in itself.

Sidenote: I am absolutely unconcerned with a physical body. I’ve never brought it up, to my knowledge. I am fairly sure I understand a dualistic mind’s existence is not strictly implying a physical body. Even if it did, its nature was surely doubtable given his radical scepticism, so it is still a moot point. No need to bring it up again for me, ok?

155

funny enough, A2 was the one i had the most problems with. to me, what A2 really says is:

A2: E(I) such that D(I, M(I)).

you already admitted that existence was an implicit assumption in the past (you hinted that you recognized it, at least), and now you still don’t want to make it explicit.

what universe do you live in that you can have doubt without assuming you exist?

i think, as erislover has said, the root of the problem here lies in your taking existence to be a first order property. you can’t simply introduce “I” as a specific case of something without quantifying it with existence. to try to prove something exists assumes existence is a first-order property, and proof of such a thing leads to more paradoxes than the one already cited.

156

Funny, nobody yelled X posts ago, when E(x) first came up…

Problem 1: Descartes’ argument is based on a ‘duh, this is obvious’ stance. Consider the contrapositive: If I didn’t exist, I wouldn’t think. More generally, if you don’t exist, you don’t do anything, period. You don’t percieve anything, you don’t think anything, you don’t anything anything. Taking that and re-contrapositiving it, you get “Anything implies that I am.” Including this argument. including anything. I don’t even have to make it specific to ‘I’, or you, or whatever, because if you’re able to make an assertion about anything, then you’re either able to make an assertion, or to be mistaken in thinking that you were making an assertion, and that’s something that you’re doing. You’re doing somehing, therefore, You Am. Semantic arguments about thoughts and whatnot are irrelevant, anything can go in the antecedent. All of detail-bashing is absolutely irrelevant.

Why, then, did Descartes write “I think” rather than “I anything”? He actually kinda did. His definition of “a thinking mind” covers a wide range of things. If you’re annoyed at me, then you think, therefore you am. If you’re imaging that you exist, then you think, therefore you am.

By the dine you’ve applied formal logic at all, you’ve finished the argument, because that is thought You think, therefore you am. If you weren’t amming, you wouldn’t have asked the question!

Disputes about the definition of thoughts, the mind, the self, and the interrelations between are little more than attempts to cloud the issue, unless you have a good reason to be making them. For example, if you have some kind of working definition of ‘I’, which is more restrictive than mere existence. In cases such as these, straightforward assumption of “I think, therefore I am” could very easliy to lead to misleading results, due to interpretation error. This is not a concern if you’re questing for bare exisence. That is obvious.

Here is a formal proof for your existence; read carefully:

A1) Shoehorn.

If at some level you are aware of the text on this screen, then you satisfy the prefix Z(you). As erislover so belatedly pointed out, that statement not only implies that you have the property Z, but that you exist. QED.

If you conclude that there are thoughts, but refuse to conclude that there is something concluding that there are thoughts, then you are overdefining I. Abandon your preconception, and accept: You are.

Now all the persons who are awake will come raining down upon me like a fire from the toaster. Why, they will posit, did Descartes bother to write “cogito ergo sum” when “sum” is sufficient? Answer: because Descartes wasn’t just proving that he existed, he was proving that he could be prove that he existed, to himself. Metacognition is required to be aware of ones own thoughts. It is not enough to just think ‘I am’; a person who was merely thinking ‘I am’ would be unable to verify that any more than he could verify ‘there is a three-toed octopus in my dressing table’. To confirm one’s existince beyond doubt, one must think about the fact that one is thinking. Thought only validates existence once you get on the ball and realize that you are thinking about wether you are thinking, and the prefix IsThinking(I) implies an I!!!.

This is like the pragmatic determination argument: if we exist in a deterministic universe, then we don’t have a choice, but if we don’t, we can choose wether to believe we’re in a deterministic universe. So, choose to believe that your choices are up to you. Except, with existence, you don’t have a choice! If you didn’t have existence, you wouldn’t be able to ask the question! So by the time you have thought to ask the question, you have the answer: you do exist. Period.

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On reflection, I believe you are incorrect about E(x) being unusable.

The assertion that E(x) is an invalid prefix is incorrect because E(x) was not being written as a first-order propsition. The paradox of negative existential propositions applies against a case where E means existence in the set of things being considered in the proof.

For example, we could (for some reason) be writing a logical argument about the properties of mythical creatures. If, in such an argument, you were to write, IsPegasus(A), the expected response is not “You can’t assert anything about pegasi because they don’t exist!!”

Obviously with Descartes we’re considering things to be in the set that we don’t necessarily consider to really exist, otherwise how could we doubt their existence? Write “I think I don’t exist” without an E(x), whydontcha. Or “I think therefore I am.”

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Having had time to cool, I apologize for my tone two posts ago. I got irate for a variety of factors, not the least of which being the ‘out-of-the-blue’ attack on the use of E(x), which was hardly new on the scene (I wasn’t even the one who first presented cogito ergo sum as a logical argument) and the fact that it looked like erislover was being deliberately obtuse.

Not that I’m retracting the content of the post. My statements are reasonable, my attitude was not.

Among other things, I didn’t even reply to your post. I will do so now.
*E(x): x exists

Existence is, at the very least, not a first-order property (if it is a property at all).*

As was clarified in the previous post, E(x) is not a first-order property, in the context of this argument.

*M(x): x has a mind capable of doubting
D(x, y): x doubts y

I don’t think that seperating these accomplishes anything.*

I have perhaps been confusing the arguments of teh various people debating me. At least one person has taken the stance that Descartes implied the existence of thoughts, but not a mind. The M(x) definition allows me to address the argument from a ‘mind’ perspective, since Descartes never actually talks about ‘thoughts’ independ of a mind. The goal was to logically prove the existence of a mind, as opposed to just thoughts. Russellian arguers were supposed to take note of it.

And the ‘doubts’ is different, because while people can (and have) denied the existence of a mind, if you’re not allowing doubting, you’re not talking about Descartes. Different things.

*A1: Ajk.( D(j, k) -> M(j) )

So are we saying doubts cause minds, or minds cause doubts? Also, what distinguishes a doubt from a mind (one of my sticking points, you might remember)?*

Nope. Read the thing. “If anything (j) doubts anything (k), then that thing (j) must have enough of a mind to entertain doubts.” This gives the Russellians something specific to hang their denials on, so we could keep the discussion orderly. You obviously consider this axiom to be true, since you question the difference between the concepts. Others might disagree.

And, implication(->) doesn’t imply causality, remember.

*Summary of L4: From this we conclude that, because I have the capability to doubt that my mind exists, I can know that my mind exists.

No you cannot. That’s what E(x) is for.*

Summary of L4: (L4: M(I)): I has a mind. Or, to include the argument that leads up to it, From this we conclude that, because I DID (assumed, A2) doubt that I have a mind, I can know that I have a mind." This has nothing to do with the ‘exists’ that the argument talks about; by this argument, we haven’t yet established that I exists any more than unicorns do. We have, however, concluded that I has a mind. We haven’t yet concluded E(I).

Because E(x) is NOT a first order property, M(I) -> E(x) needs to be assumed or concluded before we can jump from M(I) to E(I). That would be A5. You can doubt the axioms, but the symbolic structure of the argument is sound. (IANA symbolic logician, technically, but my professor who was one said I should go into the field.) If it concludes things that you don’t agree with, the place to dispute is in the AXIOMS. Which, as you recall, I assumed you were going to do.

*I’m going to have to differ with you here; if he’s succeeded with the rest of the argument, then there’s nothing hasty about it. Descartes was of the opinion that he had demonstrated the mind’s existence without referring to the body or senses…

Which is absolutely irrelevent to whether a mind needs a body or senses to exist, which is what you claimed. Suppose there is a body for my mind which must exist for my mind to exist as a matter of metaphysical fact. Note that if I were to accept Descartes argument, this assumption is never used. That does not mean it is false (your claim).*

Suppose you are wondering wether A can be done without first doing B, or in the absence of C. In response, I show you an argument that does A without first doing B, and in the absence of C. Is it not reasonable that your question has then been answered?

Descartes was stating an obvious concern that followed from his assumptions to date (that the body and senses might not exist) which, as you stated, was absolutely irrelevant to his argument; he does not use it or reference it again. I strongly suspect that, in a similar manner to my “Does A require B & C?” example just above, he considered the question answered.

*What was demonstrated, I asked. The answer: Two things, a mind and its existence.

Then we return to my previous objection laid out in my previous post: if from the evidence of one thing (the thought of doubt) we conclude the existence of two, then we either didn’t state some other things we didn’t doubt, or we didn’t doubt things we should have. One example would be your A1 which I call a comment on the grammar of “to think”. Another could be the psychologistic obviousness of A2 which is immediate knowledge, something I commented on much earlier with respect to memory which is appealed to in Descartes’s argument (most obviously in that ‘but I was persuaded’ commentary).*

The two things are M(I) and E(I), which are not the same. (For one thing, E(x) does not imply M(x). Doubting something does not prove it doesn’t exist. After doubting the existence of his mind, he is certainly allowed to later overturn that doubt in the face of evidence.

Descartes uses past tense liberally throught the argument, usually in reference to earlier (“previous”) parts of the argument/document. He is referring backward in this sentence; so it is reasonable to expect him to write it in past tense.

But, if you want to get distortingly literal, that’s okay too. If you think that you remember an earlier thought, even if you didn’t have that earlier thought, the incorrect recollection that you had the memory is occuring in the now.

*I’d be really surprised if you didn’t dispute A5

A5 is worthless to me because of the paradoxical implications of existence as a first-order property. Consider: “As to the paradox generated by negative existential propositions, it arises in this way. If ‘exists’ were a predicate, then its negation (‘does not exist’) should be a predicate also. But if ‘does not exist’ were a predicate, then in ‘Dragons do not exist’ it would be predicated of dragons only if dragons existed. And similarly for all negative existential propositions; paradoxically, if it is to be predicated at all, ‘does (do) not exist’ can be predicated only of what does exist.” Of course this discussion can lead us far astray of where we want to be.*

Very far astray, because it is entirely out of context. We are not trying to prove that ‘I’ is in the set of discussion, which is obvious, we are trying to prove that ‘I’ exists. Different thing.

*What universe are you in, that the fact that I am doubting doesn’t imply that I have the mental capacity to doubt?

I am in the same universe as you, where when the proposition “I am doubting” is used to demonstrate “I have the mental capacity to doubt” that nothing has been demonstrated.*

In other words, you don’t disagree with A1. :wink:
*that the fact that I have a mind doesn’t imply that I have enough existence to have a mind?

What fact? It’s your conclusion. And your assumption. And thus, it is not a demonstration, either epistemologically or ontologically (and I think Descartes meant it more epistemologically but no matter, really, a circle is a circle).*

Actually, this is A5, phrased in such a way as to make it sound a bit odd not to believe it.

*d’ya suppose he’s going to ask me where I got the right to ‘state’ the definition of E(x)?

If I thought it would motivate the discussion I would, but I see no way of resolving existence as a property.*

There exists one that hopes you do now.
My argument has been stated as concisely as possible (though there was one typing mistake in it the last time I posted it). Either we didn’t state everything we couldn’t doubt and thus could “get” more from “doubt is happening” than “doubt is happening”, or we didn’t doubt everything we could have, and any claim greater than “doubt is happening” is able to be doubted.

What we have is, “MY doubt is happening”; and from that we can undoubt one other previously doubted thing. As has been previously stated.

Note Descartes’s elegance “demonstration” relies, he thinks, only on the existence of doubt. But the demonstration of a doubter relies, obviously, on the implication of “doubts imply a doubter”, at least solipsitically. So we have at least two things that are beyond doubt. The metaphysical implication in the statement “doubts imply a doubter” or your A1 is doubtable in itself.

I think that the best way to answer this is to refer you to my post two posts back, where it is covered well enough.

Have at, I suppose.

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Well, the “list attack” is always perceived as hostile, or at least, I’ve found that people react to it as if it were hostile, so I understand the tone of your previous post and looked passed it. I have no reason to think you are actually upset about anything, though your frustration is probably as obvious as mine. :slight_smile:

What we have not found is a place where we feel we may comfortably disagree. This is likely to never happen because I find Descartes’s argument circular. If you do not, then we will argue all around that (what I see as) circle, you feeling like you’ve addressed all my arguments, and me feeling like you’ve only pushed the responses I need over a little until we’ve come full circle again.

Some more general comments: I’m not keen on this presentation with logic for at least two reasons. The symbols seem nonstandard to me. That’s a nitpick, though, not a criticism. Second, while some sort of informal or formal logic may help motivate the discussion, by its very nature it cannot be or replace the discussion. The universiality of logic is a downfall in a proof that perportedly doubts everything that can be doubted… especially such universal application as logic. Third, I’m nitpicky as hell, and that can be an annoyance. Sorry. :slight_smile:

OK, some more specific comments. I feel an absolute need to backtrack. And what I want to backtrack on is my own presentation of why Descartes screwed up. Because while I think the point he did is obvious, it may not exactly be as easy to “see”.

Descartes argument is largely epistemological, not ontological. However, he makes an ontological argument, one that has, he claims, absolute certainty. Let’s be careful, then, to distinguish between the epistemologically certain argument from what the argument is actually about and “saying”, which is ontological. There is only one begged question, and it is ontological. The reason we have epistemological certainty is because of that. The circle is not instantly obvious, I will grant.

But to avoid quoting the same passages to prove our points, I will attempt to construct a new argument that proves the existence of a choice function in the same manner that Descartes seems to have proved his own existence (to himself, though I mention it parenthetically it is paramount to the proof).

Our “choice function” acts on other choice functions… specifically, what it does is compare them to its own structure (through the addition of symbols to the system or through a godel-numbering system, or whatever) and rejects them if it doesn’t find equality. Is this clear? It is a function that “reads” functions and eliminates anything different from what it compares it to, which is itself.

First, let’s brush off the impossibility of this task from being, for example, something that can actually be done. If you will critique that point, I will simply doubt that Descartes “really” doubted everything, and we will never progress. That way lies madness.

Next, let’s make a VERY IMPORTANT NOTE. This is really where the problem comes into play, and why Russell might take more interest than most (and he did). The function cannot reject itself. But, this is not a proof of the existence of the function, this is the definition of the function. This is how we’ve set up the problem!

How this pertains to Descartes.

What is important to note is that in the first meditation, where we doubt and doubt and doubt, the constraints of language forbid a clear construction and focus on an intuitive one—which is fine. Only the positivists would bitch about that. Let them whine, I don’t care. But in the second meditation we work to make a positive proposition, and Descartes didn’t want to make it an assertion, he wanted to demonstrate it. The task at hand is rather literally to meditate; that is, to sit and think on such a thing. Though the universal nature of the demonstration is such that each of us could do it, that nature is itself outside the scope of the demonstration because everyone but the doubter is being doubted.

But the question is begged already here, for what we are trying to do is doubt the existence of the doubter which, we think, is absurd, because I am obviously doubting. And this is obviously true—because it is circular. It cannot be false! Perhaps a clearer exposition follows.

The epistemological path to take is: reject everything that doesn’t “have” to be true. Let me repeat that with proper emphasis: the epistemological path to take is: reject everything that doesn’t have to be true. Obviously the only thing that remains is the path itself (and whatever the path is dependent on). This does not and cannot demonstrate the existence of the path, an ontological proposition which is asserted. The demonstration, which is epistemological, is certain: because it relies on the asserted ontological “thing”.

Thus, to say it in summary, the certainty of “I think therefore I am” is not in question by me. Indeed, it is most assuredly true. But its subject matter, the ontological “I”, defined as the source of doubt dealt with in the first meditation, is presumed. Thus we come to the fairly obvious point that if I am doubting, I am.

The uniqueness of the argument is not the case; the demonstration is the same whether we are doubting, thinking, being aware, etc; in short, the exposition is true in all cases where we consider a solipsistic I in the first place, which we have.

Consider: “I (ontological thing) want to doubt (epistemological action) everything I (ontological thing) can. I (ontological thing) cannot doubt (epistemological action) myself (ontological thing, symbolic substitution for “I”). Thus, I am absolutely certain (epistemological claim) that I exist (ontological assumption already made).”

What I would (and do, in fact, as a result of my own investigations into philosophy so far) say: “I exist.” I gain nothing by epistemologically drawing out an ontological assumption.

Does that help make my objection clearer?

Specific responses not directly applicable to the above,

Well, you work with what you can, and that applies to you as well as me. The E(x) issue was fine at the time because nothing “hinged” on it, so let it slide, you know?

No. We have not done it in the absence of C, we have considered it without considering C. I can demonstrate the user’s operation of a computer without considering how semiconductors work. Semiconducters are needed for the computer. Seperate questions. See?

If we weren’t dealing with a statement like “doubts must have a doubter” then I would never have brought it up. You, and Descartes, clearly want the proof to go beyond implication.

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Your protest is unclear to me, almost certainly because it’s been too long since my formal schooling in philosophy. (Terms, in particular, slip my grasp, and m-w is not being helpful about “ontological” and “epistemological”.) It almost sounds like you’re saying that Descartes should have said, “I am”, and not “I think therefore I am.”

As I recall, I addressed this in my ‘rant’ (cleaned up a bit, including typos):

Why, they will posit, did Descartes bother to write “cogito ergo sum” when “sum” is sufficient? Answer: because Descartes wasn’t just proving that he existed, he was proving that he could prove that he existed, to himself. Metacognition is required to be aware of one’s own thoughts. It is not enough to just think ‘I am’; a person who was merely thinking ‘I am’ would be unable to verify that any more than he could verify [any other random thought]. To confirm one’s existince beyond doubt, one must think about the fact that one is thinking. Thought only validates existence once you realize that you are thinking about wether you are thinking, and that that requires a ‘you’.

If this does not address your problem, feel free to try and explain yourself “to the layman”. (That would be me. :))

Oh, and now to fly to the defense:

Regarding this, I have been unclear. The response I have always meant was, this question has no effect on cogito ergo sum. Descartes used it in the dialogue to bring up the notion of doubting his own existence; he makes no attempt to answer it, and for good reason. Yes would imply that Descartes had just proved the existence of the body and the senses. Yes would imply that Descartes had just disproved the need for the body and the senses. There is not a chance he could have backed up either claim.

Basically, I don’t consider this question germaine to the argument. It was vaguely irritating that you brought it up, since it seemed to be an attempt to “disprove” Descartes argument by making him look like an idiot, which is of course a fallacious tactic. I did waste a lot of time defending the notion that yes, Descartes has a reason for stating the question, and thus wasn’t necessarily an idiot, but either way, this entire issue is of no relevance or importance.

Again with the accusations of idiocy! “Doubts must have a doubter” doesn’t imply causality, particularly not if written logically as Doubts -> Doubter, and nobody ever claimed it did.
Consider the faux-logical statement “computer use implies the existence of a computer”. It’s an implication, and true, but the computer use certainly doesn’t cause the computer to exist.

The relation of “Doubts must have a doubter” with causality is in the reasoning behind axiomatic belief in the statement. However, when the thing was written down, the causality did not carry through into the statement.