So you are saying thinking is the something that exists that is thinking, doubting and feeling? Saying that the "who" is Descartes really tells me nothing at all.

But the content of his thought is not relevant to his not being deceived about his existence. — Fooloso4

If the content of thought is empty or unknown, what meaning or relevance does the thought have with one's own existence on claiming cogito?

I meant to say whoever thinks. You asked:

Who is "whoever"? — Corvus — Fooloso4

Whoever is a name for nonexistence and unknown, hence meaningless.

in response to my saying:

whoever thinks, must exist, — Fooloso4 — Fooloso4

Isn't it a meaningless utterance?

Do you exist? Could you be mistaken or deceived about this? — Fooloso4

I do exist. But my existence is confirmed by my own sense perception of the world, the sensory perception of my own body and the actions I take according to my will. Not by cogito.

I am not advocating any of these beliefs. My point is simply that we cannot appeal to "science" as if the matter is settled or conclude that Descartes was ignorant of science because he argues that he is essentially a thinking thing. — Fooloso4

My point is simple. Cogito is logically not sound.

So you are saying thinking is the something that exists that is thinking, doubting and feeling? Saying that the "who" is Descartes really tells me nothing at all. — Janus

Although Descartes isolates himself in his room, as a thinking thing he is not isolated. As a thinking thing he is connected to thinking itself, that is to say, to what is thought not just by him but other thinking beings before and after him. The nature of thinking is something we do together, a joint project, something that occurs between human beings. The thinking self is not just the individual but thinking itself, which is by its nature public.

If the content of thought is empty or unknown, what meaning or relevance does the thought have with one's own existence on claiming cogito? — Corvus

That one is thinking and what is thought are not the same. He must exist in order to think.

Whoever is a name for nonexistence and unknown, hence meaningless. — Corvus

?

Isn't it a meaningless utterance? — Corvus

No.

I do exist. But my existence is confirmed by my own sense perception of the world of my own body and the actions I take according to my will. Not by cogito. — Corvus

In the second meditation Descartes says:

Well, then, what am I? A thing that thinks. What is that? A thing that doubts, understands, affirms, denies, wants, refuses, and also imagines and senses.

That one is thinking and what is thought are not the same. He must exist in order to think. — Fooloso4

Is it not the case, that he must have existed in order to think? Existence is a precondition for thinking.
Thoughts without content are meaningless. All thoughts must have its contents or objects. When you say, a thinking being, it doesn't mean much without the knowledge of what the thinking is about. Without the content or object of the thought, Cogito is not saying much more than I dance, or I sing.

?
Isn't it a meaningless utterance? — Corvus
No. — Fooloso4

A person called "whoever" sounds still ambiguous.  Whoever doesn't seem to denote anyone.  It is not, I, you, he, she or they.  It is not everyone either.  Could it be no one?  Who is whoever?
"Whoever thinks, must exist."?    How do we know unknown beings be thinking? or existing?

In the second meditation Descartes says:
Well, then, what am I? A thing that thinks. What is that? A thing that doubts, understands, affirms, denies, wants, refuses, and also imagines and senses. — Fooloso4

These are the operations of mind which are only possible under the precondition of the living bodily existence.

Is it not the case, that he must have existed in order to think? — Corvus

You are mixing tenses.

Existence is a precondition for thinking. — Corvus

It is a condition for thinking. Whether it is a precondition is not as obvious as you think. From Anaxagoras to the present there have been educated people who belief in the existence of a non-physical nous/mind/intellect/consciousness. In addition there have been and still are those who believe in the existence of a soul separate from the body.

All thoughts must have its contents or objects. — Corvus

Right.

When you say, a thinking being, it doesn't mean much without the knowledge of what the thinking is about. — Corvus

What is the point?

Without the content or object of the thought, Cogito is not saying much more than I dance, or I sing. — Corvus

Descartes concludes that he cannot doubt that he exists and cannot be deceived about his existing. He might be dreaming that he dances or sings but even if he is dreaming he is certain that he exists.

A person called "whoever" sounds still ambiguous. — Corvus

Whoever mistakes "whoever" for what a person is called is confused. This reminds me of how the Cyclopes is fooled by Odysseus.

These are the operations of mind which are only possible under the precondition of the living bodily existence. — Corvus

Right, sensing and willing are operations of the mind or of a thinking thing. You have made it clear that you think this requires a body, but this is not a good reason to misunderstand or misrepresent him, especially in cases where you are in agreement with him regarding the confirmation of your existence.

Although Descartes isolates himself in his room, as a thinking thing he is not isolated. As a thinking thing he is connected to thinking itself, that is to say, to what is thought not just by him but other thinking beings before and after him. The nature of thinking is something we do together, a joint project, something that occurs between human beings. The thinking self is not just the individual but thinking itself, which is by its nature public. — Fooloso4

Right I agree but surely to be consistent Descartes must have imagined that he had grounds for skepticism regarding the existence of those other thinkers.

You are mixing tenses. — Fooloso4

You are not understanding the past continuous tense was used specifically to indicate, the existence precedes doubting.

but this is not a good reason to misunderstand or misrepresent him, especially in cases where you are in agreement with him regarding the confirmation of your existence. — Fooloso4

You seem to be misunderstanding him blindly taking his side even the ambiguity of the claim is evident.
My point was existence precedes doubting and thinking, which is also supported by the phenomenologists and existentialists.

Right I agree but surely to be consistent Descartes must have imagined that he had grounds for skepticism regarding the existence of those other thinkers. — Janus

I don't think so. I think his doubt is rhetorical. A way to doubt the teachings and authority of the Church by feigning to doubt everything.

Added: Doubt is methodical, the purpose of which is to gain certain knowledge based on what is indubitable.

What is the point? — Fooloso4

Doubting one's own existence is a self contradiction. One cannot doubt without the preexisting living bodily existence. Doubting one's own existence negates one's own sanity.

My point was existence precedes doubting and thinking — Corvus

So you have said, again and again and again. I agree, but it is not as simple as you assume. It is not a matter of taking his side but of trying to understanding him. When you say:

Doubting one's own existence negates one's own sanity. — Corvus

you show that you do not understand him. He does not doubt his existence. That is the one thing he cannot doubt. That is his starting point.

One way to approach him is by attempting to read him as someone at that time might have. Belief in an immortal, immaterial soul was widespread and fundamental to the teachings of the Church. By substituting mind for soul reasoned thought rather than Church dogma and doctrine becomes fundamental. In addition, the unquestioned authority of Aristotle in matters of science is also called into question and replaced by certainty.

The question of whether consciousness is fundamental is an open question. We should not be too quick to dismiss Descartes because he held a similar view.

you show that you do not understand him. He does not doubt his existence. That is the one thing he cannot doubt. That is his starting point. — Fooloso4

He doubted everything even his own existence. But he thought that cogito is the only thing that he cannot doubt. From Cogito, he induced his own existence. That is not quite logical.
He should have induced Cogito from the perception of his own living body.

He doubted everything even his own existence. — Corvus

He does not doubt that he exists. From the second meditation:

I will set aside anything that admits of the slightest doubt, treating it as though I had found it to be outright false; and I will carry on like that until I find something certain, or – at worst – until I become certain that there is no certainty. Archimedes said that if he had one firm and immovable point he could lift the world ·with a long enough lever·; so I too can hope for great things if I manage to find just one little thing that is solid and certain ...

Now that I have convinced myself that there is nothing in the world – no sky, no earth, no minds, no bodies – does it follow that I don’t exist either? No it does not follow; for if I convinced myself of something then I certainly existed.

He does not doubt that he exists. From the second meditation: — Fooloso4

He briefly doubts his own existence, but then soon he realises that he thinks. He convinces himself that the fact that he thinks proves he exists. The truth is that he doubted his own existence in the beginning briefly.

He briefly doubts his own existence — Corvus

Where does he say this? He doubts his body and his senses, but not that he exists. He posits a malicious demon that will do everything he can to deceive him, but concludes it cannot deceive him about his existing.

Where does he say this? He doubts his body and his senses, — Fooloso4

You can infer his doubts are about his own existence when he doubts his body and his senses.

but not that he exists. — Fooloso4

How could he exist without his body and senses?

You can infer ... — Corvus

You ignore what Descartes says and impose your own inference based on your own opinion rather than on anything said in the text.

How could he exist without his body and senses? — Corvus

A good question, but your rejecting the possibility does not mean that Descartes thought, even briefly, that is it impossible. Imposing your own opinions onto your reading of Descartes is bad practice.

You ignore what Descartes says and impose your own inference based on your own opinion rather than on anything said in the text. — Fooloso4

The logical analysis so far seems to reveal that my understanding is accurate and clear without any prejudice or distortion on the text. I was suggesting you to use your inference to understand him better.

A good question, but your rejecting the possibility does not mean that Descartes thought, even briefly, that is it impossible. Imposing your own opinions onto your reading of Descartes is bad practice. — Fooloso4

Ditto the above.

I don't think so. I think his doubt is rhetorical. A way to doubt the teachings and authority of the Church by feigning to doubt everything. — Fooloso4

Do you think his conclusion—a kind of ontological argument for the existence of God—is also feigned? Or that his skepticism regarding the authority of the church extended to the 'holy book' itself?

Do you think his conclusion—a kind of ontological argument for the existence of God—is also feigned? — Janus

Yes.

Or that his skepticism regarding the authority of the church extended to the 'holy book' itself? — Janus

He makes good use of the good book for his own ends. In Genesis 2 after man gains knowledge God says that man has become like one of us. God blocks them from eating of the tree of life and becoming one of them, that is, immortal. But Descartes, in agreement with the NT, says that the soul/mind is immortal.. The theme of being god-like is continued in the story of the Tower of Babel:

The Lord said, “If as one people speaking the same language they have begun to do this, then nothing they plan to do will be impossible for them.

(11:6)

In the fourth meditation Descartes says:

I know by experience that will is entirely without limits.

and:

My will is so perfect and so great that I can’t conceive of its becoming even greater and more perfect ... — Fooloso4