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The Contender
Con (against)
3 Points

Cogito Ergo Sum is Bunk

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Voting Style: Open Point System: 7 Point
Started: 7/31/2014 Category: Philosophy
Updated: 7 years ago Status: Post Voting Period
Viewed: 7,869 times Debate No: 59798
Debate Rounds (4)
Comments (16)
Votes (3)





The argument "I think, therefore I am" fails to prove its conclusion.


I don't think either of us intend to play the semantics game in this debate, so I'll keep these general.

The self, one's conciousness

Thinking: The process of using rationality and/or logic to come to conclusions

All other terms requiring clarification once the debate has started will be defined using the merriam-webster online dictionary definition that best fits the context of this debate [1]. If there is a dispute on which definition best fits the context of this debate, the final arbitration is reserved for myself.

Any specific stipulations Con wishes to make should be request in the comment section prior to accepting.


1. First round is for acceptance

2. No new arguments in the last round

3. Any questions on this debate should be asked in the comments section prior to acceptance

4. No semantics/ trolling



I accept.
Debate Round No. 1


Definition Amendments:

I = the self, the being one identifies as that experiences

Consciousness = the state of identifying as something (specific or otherwise), awareness of oneself.

1. Circular Logic

This is the silver-bullet argument against “cogitio ergo sum”. You could read nothing else except this argument and understand perfectly and completely why the argument “I think, therefore I am” fails to prove its conclusion. Simply put, the argument is circular. It assumes the very thing it's trying to prove [8].

By saying “I think”, you've already assumed there is an “I”, so concluding that the “I” exists from this point is trivial. You can't prove the "I" actually exists by assuming the "I" any more than you can prove unicorns exist by assuming unicorns exist.

1. II) Derivability vs Truth-Function

The reason this argument looks true even though it isn't is because the argument's proponents equivocate between the argument's derivability and its truth-value. What's the difference? Simple. In sentential logic, derivability has to do with whether or not the conclusion logically follows from its premises [1] -- truth-value has to do with whether or not it's actually true (exists) in reality [2].

To instantiate the difference, let's look at this argument (cogito ergo sum) as a derivation:

1. T>E

2. T


3. :. E

In English, the argument reads, "1. If I think, then I exist", "2. I think", "3. Therefore, I exist".

The conclusion is derivable from the argument by appealing to the conditional elimination rule of sentential logic [4], but only trivially so. Because we've assumed the very thing we're trying to prove, we can use this exact same reasoning to derive literally any conclusion we want:

1. B>U

2. B


3. :. U

In English, "1. If the sky is blue, then unicorns exist", "2. The sky is blue", "3. Therefore, unicorns exist".

Believe it or not, this argument makes perfect logical sense. It's conclusion follows from its premises, however, once again, derivability does not entail truth-value. In this example, the premise 'B' happens to be true (the sky really is blue), but that has nothing at all to do with unicorns, because we know unicorns don't actually exist. This argument has the exact same form as "cogitio ergo sum", but we know the conclusion is false, therefore we know that this argument form does not prove its conclusion is actually true in reality.

This is the problem with "I think, therefore I am" -- it doesn't actually matter whether you exist or not, because either way "I think" isn't enough to prove "I exist". You have to bring additional premises into the argument to prove the conclusion is true.

1. III) Why Con Can't Win

This puts Con in a logical trap. His argument only takes him as far as derivability. As it happens, this argument form is truth-functionally indeterminate (there is at least one truth-value assignment where the conclusion is false, and at least one where the conclusion is true [3]). You can prove that this argument is truth-functionally indeterminate yourself by plugging the function "T>E / T | E" into this truth-table generator [7].

As such, he requires additional justifications in order to prove the "I" exists. After all, a conclusion is truth-functionally true if and only if the conclusion is true on every truth-value assignment [5].

The problem is, by introducing additional premises into his argument, he tacitly admits that his original argument ("I think") is insufficient to prove its conclusion ("I am") and therefore loses the debate. If he chooses not to incorporate any new evidence or reasoning into his argument, then he's limited to circular logic, which means he fails to show that "I think" proves the conclusion "I am" and therefore loses the debate.

No matter what, my opponent cannot win for the simple fact that derivability cannot prove truth-value. Truth-value is a question of empiricism, not logic. So to prove something exists, you need empirical evidence. Logic doesn't cut it, because it's always possible for a premise to be false.

2. Counter-example

The beautiful thing about deductive logic is that if you can find even one counter-example to a deductive argument, you've proven the argument false. Therefore, if I can find an example of something that thinks, but doesn't contain an "I" (defined as a being that identifies as itself that experiences), then I've proven that "I think" doesn't logically entail "I am". For the record, logical entailment means that whenever X is true, Y is also true. If you can find an example where X is true and Y is false, then X doesn't logically entail Y [6].

My chosen example is the computer. Computers can think (thinking being defined as the process of using rationality and/or logic to come to conclusions), but they do not experience awareness. As such, the sensation of existence is independent of thought. "I think" doesn't logically entail "I am". Therefore, the argument "I think, therefore I am" fails to prove its conclusion.

It's simply insufficient.

"But wait!" You say. "It might not prove computers are self-aware, but computers still actually do exist and they still actually do think!" This is true, but it's irrelevant. We know computers exist and think because of the available empirical evidence that computers exist and think (i.e. we can observe computers in a number of ways). Once again, this debate isn't about whether or not the conclusion is actually true, it's about whether or not the premises truth-functionally entail the conclusion.

They do not.



Firstly, "cogito ergo sum" relies on circular logic to prove its conclusion, and is therefore rooted in a logical fallacy. Secondly, the argument makes the fallacious jump that one can determine truth-value using sentential-logic alone. It takes more than that. Thirdly, we have an example of a thing that can think, yet is not self-aware.

This leaves Con in a no-win scenario. He requires more than the the premise "I think" to prove the conclusion "I am", but if he appeals to anything else, he loses the debate. If he doesn't appeal to anything else, he loses the debate.

The resolution is affirmed.













My B.O.P and the nature of Scepticism for this debate.

My B.O.P is to show we cannot reasonably be doubtful of one's own existence, thereby giving oneself certain knowledge of one's own existence. I quote my opponent. " This is about epistemology". A concession that unfortunately undermines two of his objections outright.

First Formulation

My B.O.P is to demonstrate that 'I think, therefore I am' is validation of one's own existence to one's own self beyond reasonable doubt. Note Validation after the fact, not before, we assume existence, and are questioning the validity of the assumption,

I am not required to prove

1 I exist to you.

2 I exist a-priori of this debate or formulation.

3 I am anything specific.

we are looking for, as Stroud critiques in everyday terms 'Hyper Knowledge' of certainty. So, what I will do is simply demonstrate the proof, but also note something here, I am assuming a certain mind-frame of doubt, this frame of mind is central to the arrival of 'Cogito ergo sum', my opponent must also be aware and apply exactly this formulation to his arguments, otherwise be out of context and thereby critiquing the argument mistakenly.

It is plausibly conceivable that my senses could be wrong all the time. I see something far away, I am confused to what it is, it seems like X, but turns out to be Y. I am uncertain that my senses provide a stable platform for the certainty of my sensorial knowledge. Perhaps, but it is not impossible to be wrong on this.I then state what can I be certain of? Well, if I am confused or 'tricked' by some scientist or evil Demon, that has created this world in front of me. My senses, body, and life is purely a work of fiction, then is there anything I can hold sure of, under this almost complete doubt.

Second formulation

Well, I am being doubted. I doubt I exist, but that makes no sense, I exist and via doubt, I validate one's own existence to a certainty. Now, some say this is circular, I have been assuming I exist all along, but remember, this is NOT about do I exist, but how certain am I of my existence. It is epistemology, and not a theory of being, so any objection that is not epistemological or first person referential ducks the sledgehammer of the conclusion, that is my doubt is a sure validation beyond any reasonable doubt that I exist.

1 My senses can be doubted.

2 The real world can be doubted as a certainty of existence.

3 I can doubt.

4 I cannot doubt, I am

The conclusion being, one's own doubt is a self-evidential demonstration of certainty in one's own existence. Note, I assume existence is, so far as to question my certainty in my knowledge. This debate is about knowledge and certainty, my opponent needs to remember that.

There are thoughts, I am experiencing those thoughts, therefore I am. Quite straightforward. The context for 'Cogito Ergo Sum' arises, in that it is the certainty of being, not the formulation of being. He is stating the argument doesn't prove 'I exist', nor does it need to, I exist is self-referential, and the argument, simply gives absolute certainty to that proposition.

My opponent has to do one thing. Prove that his doubting or thinking is not evidence of his existence beyond reasonable doubt. He cannot appeal to computers or modes of logic on this point. He needs a premised argument to win this.


Circular Logic

I need to qualify 'Cogito Ergo Sum', my opponents weakest objection, but at the very least, his most extensive, is the idea that is in some way begging the question or presuming a premise. This is contextually and logically false. Firstly, the argument should be as I wrote in the comments taken in reference to its context, you cannot rip a formulation out of context and apply pressure from areas it has not dealt with. A moral argument for not eating meat, should not be dismissed on 'moral' grounds due to some economic factor, that is out of context, and likewise, my opponent confuses epistemology with being/existence.

The argument presumes the individual is asking 'what can I know of', not 'Do I even exist'. The first is an epistemological claim, while the second is a claim on the nature of being. We must assume the existence of X is in question in terms of certainty. Can we know of God's existence is not equal to 'Does God exist'. If evidence arises though that proves God's existence via certainty of knowledge then of course, we validate both without ever assuming certainty.

1 I am certain I exist.

2 I exist.

This would be in some way question begging but truly, cogito ergo sum asks us 'Can I even be certain that I exist', note we are questioning the assumption of X, and so a-priori to the argument we are on a minimal axiom of existence. And so, my opponent is misunderstanding the actual aims of 'Cogito ergo sum'.

1 I can be doubtful of my senses.

2 I can doubt.

3 At the very least if I doubt or am tricked, I am.

4 I am.

This follows logically from each premise. I feared Pro would misunderstand what is my B.O.P. So, I encourage Pro deal with the epistemological status of perceiver rather than attempt to drag the argument out of context. this objection is not relevant. I am not proving myself as existing, simply by virtue of assuming I am, but rather proving I can be certain via thoughts.

A Framework of character properties and movement inferential

I will detail specifically exactly what 'I think, therefore I am' shows on the basis of all it needs to show is the 'and/or' dilemma of inferential logic. Note my opponents argument boils down to 'begging the question. When studying logic, patterns emerge as a result of either language difficulties, note Wittgenstein. Inferential logic breaks down this, and upon reading Pro's mixed logic ( one non-spatio-referential and the other a sub-set of John Barwise's Modal application)

The misunderstanding of the argument

This is what a defence of movement premising is, in inferential logic, it is explicit. As argued by leading Logicians, Johan van Benthem and Manuel Rebuschi, no actual methodological theory of science or unity exists, especially in relation to Pro's singular truth value claims. So take 'I think, therefore I am'. I'll go through each point step by step.

A(I) is a relative,

Movement from relative flexives 'A of I, to the think' is seen below.

Ref [‘re@258;exivity’]: A ⇒ A

Cut [‘transitivity’]: if X ⇒ A and YAZ ⇒ B, then YXZ ⇒ B The next three lines are demonstrations of 'movement'.

Con [‘contractibility’]: if XAYAZ ⇒ B,

then XYAZ ⇒ B and XAYZ ⇒ B

Ext [‘extendability’]: if XY ⇒ B, then XAY ⇒ B

Note that Con and Ext together entail, this is irrelevant in so far as it is just tidying the possible worlds for my next point.

Perm [‘permutability’]: if XABY ⇒ C , then XBAY ⇒ C

I think, therefore, I am, is one of the most notable 'inferential and conjunction signed arguments in Philosophy, as argued by Jaroslav Peregrin, the movement or possible worlds role of the premises can follow from

A+ = {X | X ⇒ A}

A− = {<X 1,X 2,Y > | <X 1AX 2 ⇒ Y >}.


{X | X ⇒ A}

Is not Peano axiom, the axioms will be elucidated later on, for now, all we need is a bed mat for the language as Wittgenstein will argue that Cartesian doubt is not truly doubt but rather Language gone on holiday. As long as I route language in a very simple inferential mode like this one, my opponent needs to come up with some on point objections, in logical formulations.

I think the main problem here is Pro has copied some logic but misplaced it into an attempt to refute the thought experiment, this is a very interesting move, but it would require hundreds of pages of argument, not simply a blanket statement about the nature of truth, undefined. I can't help but just move on from this since, I can't apply it anymore into his argument.

Computers objection

Pro's best argument is still wrong. Pro's counter example of computers fail for two reasons. Pro cannot enjoin his conscious experience to that of another being, and therefore cannot say with certainty, a thinking thing requires anymore material or conscious activates that himself, therefore negating his attempt to transcribe 'cogito ergo sum' on a machine, so theoretically he is without a sound basis for his move. Also, under radical scepticism, assuming the nature of consciousness, actually assuming the nature and origin of consciousness is both fraught with difficulties and not relevant to my debate.

Notably Thomas Nagel's paper on this dismantles this approach. Thinking is also an act of conscious, and since computers do not think, to say they do not think, therefore 'I think', cannot follow, is trivially true, but irrelevant in almost all respects to what we are trying to prove. So, a computer is not relevant, because a non-conscious agent cannot think, so a computer you state is 'non-conscious', therefore won't be able to think.


Note not one thing has been said about epistemology by Pro, even though he claims this debate is about that. I have shown

1 Two sound formulations of the argument in CONTEXT.

2 A solid logical basis for inferential movement.

3 A detailed rebuttal of all his arguments.

I have satisfied by B.O.P by simply explain through Cartesian Doubt, we can achieve epistemological certainty in one's own existence. The relevance of my opponents replies seemed misinformed or mismanaged. As of far, I genuinely have not seen anything to make the statement that a thinking thing, can validate its own existence (that is certainty) via acknowledgement that its thoughts are self-referential evidence is false.


Barry Stroud, Philosophical Scepticism and Everyday Life. Published to Oxford Scholarship Online: November 2003

The Significance of Philosophical Scepticism byBarry Stroud

Oxford Studies in Metaphysics( Volume 2) von Dean Zimmerman

What Is It Like to Be A Bat? by Thomas Nagel (1974)

The logic of complementaritymore by Décio Krause

The Age of Alternative Logics: Assessing Philosophy of Logic and Mathematics

Debate Round No. 2


"This is about epistemology"

I never said this. Go ahead and "ctrl F" this sentence to prove it. Con is lying, and therefore anything Con says about epistemology in reference to my argument can be tossed outright as a blatant misinterpretation of what I've said.

If you've read Con's argument and are left thinking "what the heck is he talking about?", you are not alone, because Con doesn't know what he's talking about either. He's just copied/pasted derivations from "The Age of Alternative Logics" [1] in the hopes that you'll have no idea what he's talking about and just assume he knows what he's talking about. He literally lifted the entirety of the derivations he posted from this book (I, on the other hand, wrote all of my own).


This is why Con's derivation looks so out of place and is so poorly explained, and it's also why almost all of his sources are NOT readily available, while literally ALL of mine are. Con drops a lot of names, but makes damn sure none of what he's talking about is as simple as 1 click away for you (the voter) to verify, and this isn't an accident.

"My B.O.P is to demonstrate that 'I think, therefore I am' is validation of one's own existence to one's own self beyond reasonable doubt."

This is where Con concedes the debate. He specifies that his BOP is to show that his position is correct "beyond reasonable doubt". Firstly, this was in no way defined prior to agreeing to this debate, so this assertion is just wishful thinking, but more importantly, even if this was the case, Con still cannot prove his position "beyond reasonable doubt", and I explained why in my last round. Clearly Con did NOT check out the truth-table I linked last round. If he had, he'd see this [3]:

Remember what I said about Con's argument being truth-functionally indeterminate? It's not just indeterminate, it's equally indeterminate on both sides. 1 = always true, 0 = always false, and since there are 2 true conclusions and 2 false conclusions, it is equally likely that the conclusion is false as it is that the conclusion is true. Con may be unaware of this, but "reasonable doubt" has an actual definition, which is:

"Reasonable doubt is the highest standard of proof used in court. In civil litigation the standard
of proof is either proof by a preponderance of the evidence or proof by clear and convincing
evidence." [2]

That means certainty within the range of 98-99% [4]. That means anything under 98%, including 50%, is evidence enough that Con is wrong, and therefore Con loses the debate.

By Con's own words, he's already lost the debate.

"I am not required to prove X to Y"

Con claims he isn't required to prove this claim to me, or you, or to anybody other than himself (oneself). That's great and all, but it's entirely irrelevant. It doesn't matter who you're trying to prove something to, circular-logic is circular-logic. If I say "Unicorns are real because the sky is blue because unicorns are real because the sky is blue..." etc. etc., it doesn't matter who I'm saying that to, it's still nonsense, and that's just what Con is arguing here.

Con's Syllogism

Con provides the following syllogism:

1My senses can be doubted.

2The real world can be doubted as a certainty of existence.

3I can doubt.

4I cannot doubt, I am

This isn't even how a syllogism works. If we break this down into an actual derivation, we get:

1. S
2. R
3. I
4. C

I don't see any way to derive the conclusion from the premises using any of the rules of sentential logic [5]. Even this logic-calculator can't derive a conclusion from this series of premises [6]. These are a bunch of unrelated clauses. The only ones even vaguely related are 3 and 4, because both contain an "I", but then again, that makes them circular, as premise 3 assumes the very thing Con is trying to prove in his conclusion (line 4). So we're back to square one, Con is limited to circular logic.

If you can read any sense into this syllogism, it's because you're assuming additional premises not present in the actual argument, not because Con has laid out a sensical argument.

"He is stating the argument doesn't prove 'I exist', nor does it need to"

Yes, yes it does. Need I remind Con, the resolution is "The argument "I think, therefore I am" fails to prove its conclusion."

Con needs to show that "I think" proves "I exist" End of story.

"There are thoughts, I am experiencing those thoughts, therefore I am."

Once again, Con inserts "I" before he actually reaches that conclusion. All he can really argue for via the existence of thoughts is "there are thoughts, therefore I am", which is obviously nonsense. This is actually a very famous criticism of Con's argument [7].

You cannot say "I am experiencing these thoughts" without first assuming "I exist", so concluding "I exist" from this premise is circular-logic. there is no simpler way to explain it. You cannot prove you exist by first assuming you exist. Denying you exist is only a paradox if you first accept the premise that you exist, but accepting a premise doesn't prove it's true. That's the difference between science and a thought experiment.

"you cannot rip a formulation out of context and apply pressure from areas it has not dealt with"

Says Con. He doesn't give any reason why this is, he just asserts it as though it matters. As I've shown, even within Con's own context, he's still wrong.

"my opponent confuses epistemology with being/existence."

You mean Ontology. I'm not confusing Epistemology with Ontology. This debate comes down to 2 simple things; Proving something exists vs. proving something makes sense. Cogitio Ergo Sum makes sense when you accept its premises, but that's only because it's circular logic. The same is true with any circular argument. The fact is, you can't prove something is true by showing it's derivable from a sentential argument, you need empirical evidence. Con has provided none, so he loses the debate.

"'Can we know of God's existence' is not equal to 'Does God exist'."

Actually, it is here. We can't know of God's existence if God isn't real, because if God isn't real, then whatever means we used to come to the conclusion that we "Know God," must be false. Likewise, we can't come to know unicorns if they don't actually exist, because if they don't exist, whatever knowledge we have on unicorns will have actually been false. If it's theoretically possible to know if something exists (of something), then its existence is falsifiable, and therefore falls into the realm of empiricism [8].

"This would be in some way question begging but truly, cogito ergo sum asks us 'Can I even be certain that I exist', note we are questioning the assumption of X, and so a-priori to the argument we are on a minimal axiom of existence."

Questioning "X"? What is "X" here? Con doesn't say. I have a feeling Con is just throwing things at the screen in the hopes that something sticks. Either that, or most of Con's thoughts just didn't make it to paper. Either way, this is nothing short of an epic failure of a response.

Up until this point everything Con has said has been a fancy way of saying "We're SUPPOSSED to assume the "I" before we look at this argument." Kind of like how we're "supposed" to assume God exists before we look at any of the ontological arguments for God -- except not even theologists would make such a bold and absurd assertion to preface their argument. Oh, so we're just supposed to assume the conclusion is true before we consider the argument for said conclusion? Sorry, that's not how arguments work, that's not how debating works, and that's not how logic works.

All bachelors are single. This argument is true regardless of if it's within context or out of context. This is because logic is logic regardless of whatever overly complicated prefaces you want to obfuscate an issue with.

"I think the main problem here is Pro has copied some logic but misplaced it into an attempt to refute the thought experiment"

This is projection if I've ever seen it. Con's derivations are literally copied and pasted. There's nothing else to say, he's misplacing copied logic.

"Pro cannot enjoin his conscious experience to that of another being, and therefore cannot say with certainty, a thinking thing requires anymore material or conscious activates that himself, therefore negating his attempt to transcribe 'cogito ergo sum' on a machine, so theoretically he is without a sound basis for his move"

Does this sentence make sense to anybody? I've read it over and over again, and it just doesn't follow. Con claims computers don't think, but by the very definition both of us agreed upon prior to this debate, computers do think, so Con must, therefore, be wrong.


I think the issue here is that Con realizes he's stuck in a logical trap, and so all he has to fall back on is a shoddy attempt at confusing the issue as much as possible to get whatever votes he possibly can. Almost nothing he wrote specifically addresses my arguments to him, his sources are almost entirely Easter-egg hunts, he drops a ton of names without explicating the relevance of them, and most importantly, he defines the conditions of his victory in such a way that means he's already lost the debate.

My arguments still stand. Cogito ergo sum is a circular argument containing no actual evidence to support its conclusion.

The resolution is affirmed













The argument

In my first post, I made multiple arguments in context to what exactly 'I think therefore I am' is attempting to do. Now my opponent will not address the context and purpose of 'I think, therefore I am' and what else can I say? If you simply will not address the argument for what it is, then I can do no more but rewrite the argument again with the premises and arguments that I did in the first round.

"beyond reasonable doubt". Firstly, this was in no way defined prior to agreeing to this debate, so this assertion is just wishful thinking

Doubt, Doubt and more Doubt

This is the purpose of 'Cogito Ergo Sum', I am a little surprised my opponent would say this, does anyone else think he simply hasn't read the actual argument in its context, what is the purpose of 'Cogito Ergo Sum', where did it arise, why did it arise, what was its function? These are all questions one expects someone who would instigate a debate to understand, I am reading the argument the way it is formulated and presented in almost all the literature.

'I think, therefore I am' was proving, that we cannot reasonably doubt our own existence under radical scepticism. The argument is not an argument in the realm of being, and so, any counter argument that attempts to say 'you are begging the question/you are assuming the thing you are trying to prove, automatically fails to grasp the real crux of the debate, that is epistemology, my opponent doesn't want to acknowledge this because his three arguments rely on a more superficial reading, not an insult, but a reading of an argument that only glances at the conclusion and not the context, will always skim over the details.

Kierkegaard argues this also, 'I think therefore I am was never intended to prove existence, but to prove we cannot doubt one's own existence in any reasonable way, even Descartes wrote this in his works denouncing the premising of his formulations, which I have converted to make things flow faster. In all seriousness, has a single argument been presented to show 'we can have reasonable doubt of one's own existence? No, and since the last round cannot present new arguments, I fear my opponent has wasted his chances.

My opponent noticeably hasn't actually dealt with the argument directly, bar one counter example. Since no challenge has actually been made to this statement.

"You cannot reasonably doubt your own existence", and based on the premises explained, I have pretty much won this debate. We cannot in fact doubt our own existence, because to doubt, is to secure valid proof that we must in some part truly exist, there is not actual way to fully disprove or cast doubt on the proposition. So, to win this debate, my opponent must get into the mind-frame of radical scepticism, note he refuses to, but that simply is ignoring the context of the argument.

As explained in my opening

"you cannot rip a formulation out of context and apply pressure from areas it has not dealt with. A moral argument for not eating meat, should not be dismissed on 'moral' grounds due to some economic factor, that is out of context, and likewise, my opponent confuses epistemology with being/existence."

My opponent neither addressed this point or gave suitable arguments against it, and I feel that I am struggling to reword my argument anymore, because they are simply not being addressed in the slightest. My opponent HAS to give some arguments that one's own self cannot be doubted. Without this, my conclusion is proved, I think, the act of thinking is a valid and undisputed way to validate that one's self exists in some form.

Another formulation of the argument

I will state the argument again hopefully until there is at least some engagement. Here is another example of the argument in addition to my previous.

C. I exist ::= (∃x)j=x

Note also, on inference, if P → Q


I was never arguing, the premises are identical, for an inference, but that inference can be made by separating the premises, and the assumption of Tj, simply is an axiom, or a self-refential move, 2-3, is where my opponent needs to be addressing, but he refuses to, instead believing I am doing the above move, assuming P, to my conclusion of Q, i never did that.

Now, in this formulation, One must prove that thinking things have decent reason to reject the 2 second premise, you cannot refute the first premise, you think, is a self-referential validation, note my points on the logic of inferential that my opponent didn't challenge. So my opponent has one choice.

1. My opponent needs to show we have reason to doubt one's own existence!

He simply hasn't, and I have no way to drive this debate any further, I need counters. The majority of my opponents second post is rebuttal, so I will deal each one and also, I will deal with his questionable sources.


My opponent's definition of 'reasonably doubt' comes from a legal dictionary, not a philosophy or scientific one, he is slipping in a probability that he hasn't shown to be in any way realistic, 98-99% is his standard, where did that come from? Directly from the dictionary, he would want to actually give some format or context for this random number, note as well, he shows no link between his 'truth' table to this statistic, he simply puts them side by side, as if either has been argued or shown to be compatible. Regardless, with no argument given for 'reason to doubt one's own existence', I have won because my arguments out rank his by 100%, not to mention, no refutation was given for almost half of my first post.

His 'refutation' of my logic.

My opponent doesn't give a refutation, he gives an ad-hominem, he says I don't understand it, therefore it is wrong, he says it is misplaced but his only evidence is 'I copied it'.

If you see the post he makes, it states 'A conceptual framework', that is all it is, a conceptual framework for inferential, of course I copied and pasted it, I never said I didn't, I also went through each step stating it was just laying a 'framework' for movement. Frameworks in logic are by in large universally applicable, and so I don't think my opponent really has dealt with this in any reasonably way, and so my argument stands until a real refutation can be made.

"Oh, so we're just supposed to assume the conclusion is true before we consider the argument for said conclusion? "

I encourage my opponent to remain impartial and present his work without emotive langauge, I find it easier to read the actual points then. I never said the conclusion is assumed, because we are not assuming that we cannot doubt our own existence a-priori, we are asking 'Is there a reason to doubt one's own existence?', or is it even possible to realistically be sceptical that one's own self exists, that is 'Cogito Ergo Sum', and my opponent unfortunately just doesn't get it.

Pro gives no refutation of my Computer counter argument, he says he 'doesn't get it', but I re-read what I wrote, and it seems fine, also, I made two objections, he dismisses one but doesn't touch the other, Pro cannot attempt to disprove 'Cogito Ergo Sum' via applying his rational consciousness to that of another being, it strips the bounds of what the argument attempts to prove. One's own self conscious. It would be like applying a 'suffering principle' to a non-suffering agent, he is without a basis. Not only that but my opponent believes non-conscious agents think. Thinking is under every definition is either have/engage in

"to have a conscious mind"

"to consider something as a possible action"

"to have or form in the mind"

He simply defines it in the worst possible way to save himself actually referring to himself, which is the crux of the debate.


Pro never addresses the actual argument and its conclusion, he never once gave a 'reasonable scenario to doubt one's own existence', not one sentence to refute the statement, thinking, the process of doubt is in and to itself grounds to hold that one cannot reasonably doubt one's own existence. This debate is epistemology and doubt, that is the context of the argument and therefore any attempt to say it is 'circular' because it validates the conclusion, just misses the mark. My opponent will not admit this, and so for me, I can end it early, I have given.

1. Multiple reformulations of the argument, none challenged.

2. A basic universally applicable logical grounding for my argument

3. Refutations of each and every one of Pro's three relevant counters.


I await my opponent to engage with the argument instead of engaging in very petty name calling and pseudo-psychological analysis of 'why I wrote what I wrote' instead of, what I wrote.

Since no counters have been successful and generally no engagement has been given, Pro has no met his B.O.P, and since he cannot make any new arguments in the last round, I don't see a resolution on his side, I thought have structured myself as to present the arguments, both times in the beginning, and then refute any noticeable counters, In conclusion, I have satisfied my B.O.P and we can conclude there is no reasonable way one can doubt one's self's own existence.


Kierkegaard, Søren. Philosophical Fragments. Trans. Hong, Princeton, 1985. p. 40.

Debate Round No. 3


The Resolution

My opponent doesn't seem to understand what the resolution of this debate means. He insists that it falls to me to prove "we can have reasonable doubt of our own existence", but the resolution of this debate, which both parties agreed to, clearly says, "The argument "I think, therefore I am" fails to prove its conclusion." I have shown conclusively that it does, but rather than contend this fact, Con has taken it upon himself to argue for a different resolution all together.

For the record, it is not my burden to build a ground-up argument denying that we can prove our own existence to ourselves. My job is to show that, as the resolution clearly states, "I think" fails to prove the conclusion "I am". It may very well be possible to prove your own existence, but "I think" does not and can not lead to the conclusion "Therefore I am".

When it comes to a debate, the resolution defines the conditions for which you win or lose, not whatever Con feels like it ought to be in a given round. You cannot re-define the parameters of a debate ex post-facto just because you're losing.

It's ironic that Con insists I haven't dealt with the argument directly, when his entire effort is to circumvent this debate's resolution and substitute his own.

Dropped Arguments

There are no dropped arguments on my end. Oddly enough, the quotes Con provides of himself as evidence of arguments I've ignored are actually quotes I used and directly responded to just one round above. I responded to all of them, but my response was usually showing that the quoted argument was a non-sequitur and therefore irrelevant to this debate's resolution.

By "Pro didn't respond to this argument", what Con really means is "Pro didn't grant legitimacy to this argument." These are two very different things. I responded to all of Con's arguments, he just doesn't like that my responses didn't acknowledge his arguments as relevant and/or threatening to my case -- because they weren't.


Con claims that Kierkegaard backs him up on the purpose of the argument "Cogito ergo sum", but upon further investigation, this is yet another thing Con is sorely wrong on. Firstly, he provides no evidence of his claim (yet again). He sites a page from a book in his sources section, but once again he ensured the page is not linked so we cannot confirm his claim. No matter, because I can show right now what Kierkegaard actually had to say about this topic.

"Søren Kierkegaard's critique

The Danish philosopher Søren Kierkegaard provided a critical response to the cogito. Kierkegaard argues that the cogito already presupposes the existence of "I", and therefore concluding with existence is logically trivial. Kierkegaard's argument can be made clearer if one extracts the premise "I think" into two further premises:

"x" thinks
I am that "x"
Therefore I think
Therefore I am

Where "x" is used as a placeholder in order to disambiguate the "I" from the thinking thing.

Here, the cogito has already assumed the "I"'s existence as that which thinks." [1]

As you can see, not only does Kierkegaard not support my opponent in this debate, but his position on the argument is literally exactly the same as mine. Once again, Con's own words undermine his argument.

Another Formulation

Here Con gives yet another formulation he's ripped directly out of someone else's work without proper citation.

Please note that Con got this from a forum post, not and authoritative source. Also note that even this random person Con is using to argue for his position readily admits that the argument "I think, therefore I am" is inadequate to prove the conclusion, and that the argument requires additional premises that, in turn, require additional justifications not given. And even then, he still admits that this is only trivially true (because it's circular) [2]. Once again, Con defeats his own position.

On Reasonable Doubt

Con criticises my given definition of reasonable doubt on the grounds that it's a legal definition instead of a philosophical one or a scientific one. This is an absurd criticism for 4 reasons.

1. Con never gave a definition of "reasonable doubt" (he still hasn't), so it was left to me to assume what he was even talking about.

2. "Reasonable doubt" is a legal term, so naturally we'd use the legal definition as the assumed default.

3. There is no "philosophical or scientific" definition of "reasonable doubt". It's a legal term, after all.

4. This is a debate. Debates are analogous to court-room disputes. We have the prosecution and the defence, and we even use a jury of our peers to determine the result of our dispute. So, it's appropriate to use the legal-definition of this term.

In short, Con shouldn't set standards of evidence for himself that he cannot meet. He was the one who brought up this whole "reasonable doubt" bit, after all. It seems Con wanted "reasonable doubt" to mean 'whatever level of doubt he personally thinks is reasonable', and didn't realize this term has an actual definition.

Truth Table

The purpose of a truth-table is to show "a breakdown of a logic function by listing all possible values the function can attain." [3]. The significance of this is that it allows us to determine if an argument is true regardless of the veracity of its premises, if it's false regardless of the veracity of its premises, or if it's indeterminate. in this case, Con's argument is truth-functionally indeterminate. This is because it's a circular argument. It's only true if you already assume the conclusion is true, and it's false if you demand a higher-standard than circular logic to find an argument convincing. As such, the truth-table reveals the argument can only be said to be true 50% of the time (when you assume the conclusion is already true). Since 50% is less than 98%, logically speaking, this argument fails to meet the criteria of reasonable doubt.

My opponent could have made this easier for himself and only opted to argue "on the balance of probabilities", and then he'd have a fighting chance. He'd still be wrong, because the argument is still circular, but he could at least then argue probabilities. Since my opponent has set the standard for himself to be "reasonable doubt", he's shot himself in the knees, and lost the debate as the result.

No Refutation

Con claims I've given no refutation of his formulation. That's because it's not his formulation. He copied it and then incorrectly sourced it. He gave no real explanation of what it meant, nor could he, because it doesn't make any sense in the context of the rest of his argument. I can't argue against it because there is no argument here. He just pasted it, insisted it proved his claim, dropped a bunch of names, accused me of copying and misplacing logic (ironically enough), then just moved on to my computer-argument.

There is no argument here. He's just quoting generic passages on what 'inference' is from a textbook on logic. It has no bearing on his actual argument. It would be like if I smashed my fists into the keyboard, posted it, then later complained that Con never properly refuted my argument. You can't refute something that never made sense in the first place, all you can do is show that it's irrelevant and move on.


We both agreed on a definition of thinking, which goes as follows -- The process of using rationality and/or logic to come to conclusions.

Computers do this [4], so we have an example of something that thinks, but contains no "I" (consciousness). Since I've shown that thinking doesn't prove existence, I've shown that the argument "I think, therefore I am", fails to prove its conclusion. This is a logically inescapable conclusion given the definitions of these terms both parties agreed to prior to the start of this debate.

Again, Con will insist that the Cogito was never meant to prove the "I", but he's alone here:

"Cogito ergo sum, ("I think, therefore I am") is a philosophicalproposition by René Descartes. The simple meaning of the Latin phrase is that thinking about one’s existence proves—in and of itself—that an "I" exists to do the thinking; or, as Descartes explains, "[W]e cannot doubt of our existence while we doubt …" [5]

There you have it, the Cogito is an attempt to prove the "I" exists via thought. Since it fails to do so, cogito ergo sum is bunk.


The Cogito is a circular argument and therefore fails to prove its conclusion. Despite what my opponent will try to tell you, this is exactly what this debate is about, as the resolution of this debate directly states. He's wasted his time trying to subvert this debate's resolution rather than trying to actually argue his position, and therefore has failed to uphold his defence of the Cogito. You may or may not actually exist, that's not what this debate is about. This debate is about if thinking proves consciousness. It does not. Case closed.

Arguments: Con's were irrelevant. They argued for a different resolution than the one this debate is about.

Sources: I provided more and better quality sources than Con. Most of his were not readily available, and Con made no effort to denote which arguments came from which sources. Also, one of Con's only readily-available sources is from a forum.

Conduct: Due to Con's lazy sourcing, it is needlessly difficult to tell which arguments are his and which are lifted from other works. He 'sort of' sources the arguments that aren't his, but does everything in his power to make determining what's his and what isn't as hard as possible for the rest of us. This is about as close to plagiarism as you can possibly get without straight-up stealing arguments.

Thank you for your time






Overview of my position

In my closing post, I will give an overview of how my arguments were presented. I argued, like Descartes argues, that the process of conscious thinking, is evidence, that we cannot reasonably doubt our own existence. That is in essence 'I think, therefore I am'. This is a conclusion to previous premises in Descartes work.

My B.O.P was to explain and extend 'I think, therefore I am', and await counter arguments to show that thinking 'is not reasonable evidence for the statement, one's can doubt one's own existence.

My opponent's B.O.P was to refute the conclusion of 'Cogito Ergo Sum', that is he must give adequate reasons to suppose that thinking, that is conscious doubt, is not adequate, and we can still have reasonable doubt of one's own existence. I would now like to ask, did my opponent give a single argument to that conclusion? He did not, and therefore did not satisfy his B.O.P, even when I explained in detail what the argument attempted to prove.

My arguments ranged from

1. Multiple formulations and premised points to the conclusion of 'Cogito Ergo Sum

2. A platform in inferential logic, to allow movement, that is 'moving premises'

3. A second logical formulation of my argument

4. Detailed counter arguments.

My opponent only presented three arguments, and retrospectively failed to counter my objections.

His arguments.

1. It is begging the question/circular reasoning.

2. A logical formulation.

3. 'computers' think, but are not conscious example.

1. Notably his first argument is his weakest, as I noted in detail, the argument is not establishing existence from non-existence, but establishing a knowledge claim to one's own existence, one's own existence as I pointed out is a self-refential validation, and it is 'can we doubt our own existence' is the heart of the debate, not 'prove I exist'.

2. This is simply a rehash of point 1, and I referenced this in my rebuttal.

3. My opponent states "thinking" is using 'rationality', now firstly this is not a standard definition, with no reasonably argument to back it up, as I pointed out, and secondly, rationality, is a state of mind, it is 'being rational', a computer can rationally deduce formulations, but it cannot reason them rationally, and so my opponent is sneaking a hidden premise into this argument, like I pointed out in my first post. My opponent also notably ignored my objection, he stated he 'couldn't understand it', well, I gave two objections, he dismissed one, and ignored the other.

Conclusion, my opponent's three arguments failed to be relevant/ failed to be defended upon further inspection.

Now, in relation to my opponent's closing. My opponent cites, a source I use, but unfortunately cites a portion, I wasn't citing, so in fact he is saying that I have to argue everything on the page, even though I selected my point carefully, that is just a bit absurd.

On reasonable doubt

My opponent claims no definition in philosophy is given, has my opponent read the material we are debating, I suspecting he hadn't, and considering he misunderstood the argument, it is no doubt he would also assume there is no basis for it, in summary Descartes defines reasonably doubt as "Any valid doubt that can be given, any logically possible scenario that can be produced to negate certainty in the conclusion." I expected him to actually read the material we are debating.

"So, it's appropriate to use the legal-definition of this term."

This is a philosophy debate, so no it isn't.

"This is because it's a circular argument."

Pro concedes his logic table is just a rehash of his points about begging the question, thereby proving he only produced two notable arguments, the computer and begging the question. Since I went into paragraph after paragraph trying to explain the conclusion and purpose of 'Cogito Ergo Sum', I can only assume my opponent didn't want to debate the real conclusion of the argument, and secondly the computer argument was refuted easily. He gave no real explanation of what it meant, nor could he, because it doesn't make any sense in the context of the rest of his argument.

"He's just quoting generic passages on what 'inference' is from a textbook on logic."

'Generic passages'? I have no clue what my opponent is referring to, as generic, also a basis or framework is obviously going to be universal, especially on inference, that is why I detailed the premises along side the argument. In conclusion, my opponent just didn't have any notable counters to my formulations, simply saying 'it doesn't make sense to me' is not adequate.

""[W]e cannot doubt of our existence while we doubt …" [5]"
A concession that he really did know the conclusion of the argument but wouldn't deal with it. And so, we don't, the conclusion is we cannot doubt our own existence, it is a pity this late in the game we actually agreed on this, and I probably would have been more engaged if the debate stayed relevant. I can't explain anymore that Descartes intended the argument for epistemology and that Pro's arguments were just not relevant. Pro states my arguments were not relevant, but unlike my points, which detailed why he was not relevant, he just states I am, without explanation.

Pro's Conclusion

Pro spends a large majority of his time, actually he spends most of his time, trying to gain points from voters, ignoring the actual arguments to simply state he likes his 'source layout's better than mine. That is fine but is that really what we should focus on? A passing remark would suffice, but since there was a lack of arguments on Pro's side, and I had to keep explaining my position, it became very one sided. Pro also spends alot of time stating I copied points and it was close to plagiarism. Plagiarism would be if I stated I wrote the points out myself, and didn't cite. I did cite, I had sources, and I won't be dragged into petty point scoring, I think this debate should have focused on the points, not simply keeping a score on a website, which is what Pro's conclusion is, a walk through of nice sources and grammar. I could engage in this

"We're SUPPOSSED to assume the "I"" On Caps locking a full word, but truly I won't go that low, or how Pro was incredibly condescending, but I prefer to keep it formal and without petty remarks, so I will continue onto my conclusion

My Conclusion

I have given ample arguments both in paragraphs of text, and in logical formulations, no real argument was given by pro to the conclusion 'thought is not reasonable evidence against the proposition that we can doubt one's own existence. No counter arguments to my formulations, no thought experiments and no engagement with the title and resolution, made this debate very one-sided for me. With the combined force of my arguments and rebuttals we can conclude that I managed to prove my B.O.P. For that reason and for the reasons I gave positively, we can conclude that 'Cogito Ergo Sum' proves that we can have certain knowledge that we do in fact exist in some form, and that we cannot reasonably doubt one's own existence.


Debate Round No. 4
16 comments have been posted on this debate. Showing 1 through 10 records.
Posted by DeletedUser 7 years ago
Arguments: Con's argument against circularity is unconvincing; certainly the premise "I exist" must presuppose one's existence in order to be true regardless of the context, hence assuming the conclusion of the argument. But Pro's argument that circular logic demonstrates that the argument fails to prove its conclusion is similarly unconvincing. In arguing that the truth of the conclusion is assumed in its initial premise ("I think") he implicitly concedes that the implication is accurate*, hence he must prove that the initial premise is false to satisfy his burden of proof which he fails to do.

But Con fails to point out this problem in Pro's argument, and without doing so he fails to give a convincing reason why the premise "I think" must imply "I exist." Con's argument ends up off case; he fails to defend that "I think, therefore I am" successfully proves its conclusion ("I exist") and instead argues that in context the argument was never intended to prove existence. It's unclear how the context of the argument relates to its ability to prove its conclusion when he ends up arguing against his burden of proof.

Con's thought salad like "[Thinking is also an act of conscious], [and since computers do not think], [to say they do not think], [therefore 'I think'], [cannot follow], [is trivially true], [but irrelevant in almost all respects to what we are trying to prove]." is often incoherent; commas do not make an argument cogent. Pro's comment: "If you've read Con's argument and are left thinking 'what the heck is he talking about?'" perfectly sums up how I felt about large portions of Con's case.

I'm not awarding convincing arguments.

*(This is in contrast to his alternative example (1.II); while 'I think' does presuppose 'I exist' as Pro argues, 'Unicorns exist' does not in any discernible way presuppose 'the sky is blue' -- hence while this alternative is also logically valid it is NOT circular.)
Posted by dannyc 7 years ago
We were talking past each other for the most part, check out the context and conclusion of the argument, the epistomology of 'to doubt's one's own existence', that may clarify things.
Posted by DeletedUser 7 years ago
It seems the counterarguments to Ryuu's opening argument should be fairly trivial so why do I have to think so much to make sense of Con's argument? :(

I'll get back to this later.
Posted by RyuuKyuzo 7 years ago
I wrote it in openoffice and ctrlc/v'd it, so maybe something happened there.
Posted by 9spaceking 7 years ago
maybe you accidentally double spaced
Posted by RyuuKyuzo 7 years ago
I don't know why the spacing between my paragraphs ended up so big. Hopefully that won't happen next round.
Posted by 9spaceking 7 years ago
dannyc is about to get pwned.
Posted by RyuuKyuzo 7 years ago
Hmm... I wish you would've let me edit the definitions section of the debate before accepting, but w/e.
Posted by RyuuKyuzo 7 years ago
I ask because, by consciousness, I mean "awareness" -- The "I" being the thing that experiences awareness. This seems to be fit in with what you're saying. You're proving you exist via thought to that which experiences these thoughts (i.e., yourself).

if I added in the definition of consciousness to mean "awareness of oneself", would that sufficiently fit in with your argument?

I = the self, the being one identifies as that experiences

Consciousness = the state of identifying as something (specific or otherwise), awareness of oneself.

For the record, I'm not planning on rooting my argument in what consciousness is and is not, but incase it does come up, it's better for us to have an agreed upon definition ahead of time.
Posted by dannyc 7 years ago
I'm not, whatever I am, 'I am'. So, I could be a machine, I could be human, God, an alien, a brain in a vat. Doesn't matter, I simply 'am', and byond reasonable doubt of myself, I am.
3 votes have been placed for this debate. Showing 1 through 3 records.
Vote Placed by Smithereens 7 years ago
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Reasons for voting decision: Argument 2 was actually Pro's silver bullet in the argument. It'snot even a valid syllogism without some presupposition assumed true in order to qualify the function. In fact, its not even a syllogism. I was interested upon reading this to discover what Con said in response, and lo behold, nothing. Pro wins. I would have been more interested in an argument by Con that questions how Pro could expect to formulate an argument that could be considered true. For us to consider him true, we require some construct of existence right? Or else, upon what is the logical functions present in this debate contingent upon? And thus how does Pro expect anyone to believe him? The simpler questions are what would have made better arguments, not some pastings from a book on propositional calculus.
Vote Placed by Anonymous 7 years ago
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Reasons for voting decision: Conduct: Con misquotes Pro, and his sourcing doesn't adequately indicate which statements are his own and which are not. This isn't enough to be considered plagiarism, but it's enough to warrant the conduct point. S&G: Con is often unintelligible on account of overusing (and inappropriately using) commas. Convincing arguments to neither. See comment 16.
Vote Placed by daley 7 years ago
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Reasons for voting decision: Since Con clearly showed how unreasonable it is to doubt one's own existence "I am" as long as one is conscious, I think he made the stronger argument. Pro actually argued that computers "think," which they don't; and had to define "thinking" outside of consciousness, which showed the weakness of his argument.

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