Previous experience has shown that Corvus will not correct his errors nor accept any interpretation not at one with his own, apparently now to the point of extremis.

On the other hand, he has quite successfully made this thread about himself. — Banno

As I said quite a ways back in the thread...

It can be helpful to understand that some posters post seeking narcissistic supply, and admitting having been wrong is never part of that 'plan'. In such cases, it's good to be able to recognize that one has made a mistake oneself, in thinking that one is dealing with a reasonable person. — wonderer1

Still, I was hoping you could falsify my working hypothesis.

For better or worse, life has trained me to have strong pattern recognition of narcissism. (Both grandiose and vulnerable type.) I would have preferred being shown to be wrong.

Well, we might re-set by considering what it is to be certain. seems to have been satisfied with evolution as a source of certainty, which is a bit weird but perhaps they will not mind a change of direction.

Certainty is, on some accounts, indubitable belief.

Now there are all sorts of things that go undoubted. Are we certain of them all?

Or do we need reason, justification, warrant, to doubt?

It's not just my logic. — Banno

Who else is saying what you have been saying? Although, it doesn't matter how many folks are saying the same thing. Ultimately what matters is the truth. Later~

Any logic text you choose.

That's kinda why I have been backing up and checking what I have writ with the tree generator.

(Edited - I assumed the wrong author)

P -> Q. P thinks. Therefore it exists. P can’t be said to not exist if it thinks.

If P doesn’t think. It may or may not exist. For instance P may be dead, or may be in a meditative state or in a coma…. Or it may be a fly on the wall incapable of what we

So then we have:
~p -> (q v ~q)

Now to go the other way

If q exists, then it may or may not think. It may be a bug. Forget the fact that bugs “might” think. Say amoeba instead of bug.
q -> (p v~p)

But if q doesn’t exist then it doesnt think. A logocal impossibility.
~q -> ~p

That I think is as far as it can be taken in a limited scope. And I see no refutation of cogito ergo sum.

Or another simple way: existence doesn’t necessitate thinking, but it doesn’t preclude it either.

2 variables, so we have 4 entries in the truth table. No need for any more. Of course if I err please chime in!

Sure, all that.

But what you have not shown is that if P thinks then it exists.

Have you a proof of that?

Here we go again.

Certainty is, on some accounts, indubitable belief.

Now there are all sorts of things that go undoubted. Are we certain of them all?

Or do we need reason, justification, warrant, to doubt? — Banno

Unfortunately I haven't read On Certainty. Off the top of my head I'd say it's a big subject and I'm apt to start talking about our neurology and how it can result in doubt arising subconsciously in a way such that reason, justification, and warrant aren't the most applicable terms to be using.

On the other hand, I consciously consider doubt in the reliability of the cognitive faculties of myself and others to be a matter of good epistemic hygiene.

In any case, I'm not good at knowing how to respond to such an open ended question. So I'll leave it for you to clarify if you want to discuss things with a more specific focus.

[

But what you have not shown is that if P thinks then it exists — Banno

No. P may or may not be capable of thought. A coma vegetable for instance. Or P may be an amoeba. Or a philosophy professor.

But that fact does not invalidate the cogito.

This covers it: q -> (p v~p)

But that fact does not invalidate the cogito. — Metaphyzik

No; nor does it validate it.

Why should we agree with the cogito?

This covers it: q -> (p v~p) — Metaphyzik

But, ¬q → (p ∨ ¬p) is equally valid. Note the negation.

Give me a real world example of

P-> ~q

I believe this is just sophistry.

An example of something that thinks but doesn’t exist.

But, ¬q → (p ∨ ¬p) is equally valid — Banno

So not existing, implies that it thinks or doesn’t think? That is invalid. It obviously doesn’t think.

Real world example? Or are we playing games with letters ;). Haha

So you are certain of the Cogito without any justification? — Banno

I don’t know what you are asking me.

If you are asking am I certain that I exist while I am in the act of thinking “I exist”, than yes - I am certain of this. Something is up, and I am certain of it at that moment. And that is something I can know, while in the acting of knowing I am existing there still…. It’s a phrase like “knowing now” that describes this moment, this place. Immediate certainty of my own becoming that is seeming to forever keep coming once I am being aware of it……aware of being “I am”, calling my own name because “am calling told me I could.
Certainty of all that which is really nothing but “I am”.

If you are asking me whether the statement or syllogism “I think therefore I am” is valid, or sound, or both, or neither, or equivalent to “if P then Q”, than I am only mildly interested in that discussion because I think those things have little to do with what Descartes observed.

Here is the thing, I can’t tell if you think the above two questions I posed are different questions, so that’s why I started this post with “I don’t know what you are asking me.”

You asked me a question and I answered you the best I could, posing two interpretations and answering them both.

Now let me ask you an honest question. Can you say what Descartes meant (or gets credit for for some reason even though any idiot knows “I am” for certain)? What did Descartes mean?

Without letting some syllogism, or logical, third-party verification, constrain you or set you free or justify your words - just what do YOU think Descartes meant. I am not asking you whether you are certain of it, or whether you are certain of it with or without any justification. My question is simpler. You have to see what I think Descartes meant. What do you think Descartes meant?

The opposite of p->q is of course p->~q

It is not ~p -> ~q

I think that is your logical error

Note the negation. — Banno

That there are green crows implies there are no new ideas.

Now let me ask you an honest question. Can you say what Descartes meant (or gets credit for for some reason even though any idiot knows “I am” for certain)? What did Descartes mean? — Fire Ologist

Well, I'm not at all sure - that's somewhat the point.

Some folk think he was making an inference - you seem to think otherwise, and no one has set the inference out for us in a valid way.

Some folk think he was setting out an intuition. But if that is what he was doing, then can we coherently say the intuition is justified, as is needed if it is to answer the question in the OP - that we know we exist.

Some folk think it a definition of "I" - that his argument is that I am what thinks. That has various novel problems, pretty much not considered so far.

Now I've said quite a few times in this thread that I do not think we need be "100% certain" in order to get on with things. I think the phrase sets up a bad framework for dealing with doubt and certainty. I am being a pain in the arse in order to show that there are issues with the very notion of insisting on being "100% certain".

The opposite of p->q is of course p->~q — Metaphyzik

Actually, it's ~(p→ q).

What I was pointing to is the triviality of your

This covers it: q -> (p v~p) — Metaphyzik

Both ¬q → (p ∨ ¬p) and q → (p ∨ ¬p) are valid.

My overall impression is that logic is not a strong point hereabouts.

Well the operators in logic have to relate to something.

And they are contextually relevant as that defines their set. Their axiomatic assumptions

So… give me an real world example of your logic and then I’ll consider what your atoms are made of ;)

So you are certain of the Cogito without any justification? — Banno

You said “justification”. I thought of a third way to address your question.

You distinguished “certainty of the Cogito” from “without justification”. In order to justify certainty, or justify anything, I need some framework, to judge the certainty as justified. I have to clarify one thing “certainty of Cogito” and clarify some means and framework of justification, and then marry the two I suppose.

In order for me to justify the certainty of “I think therefore I am” I would have to be justifying, be in the act of justifying, to myself, to you, to whomever, about whatever. At the Cogito, the details are all drained and the only thing left is being, or becoming at best, like justifying or doing anything’s else.

The clearest meaning of the Cogito starts looking at the act of justifying, or now the act of “looking” at the act of justifying. It’s always an act that is the subject. An act of being, stated simply. It may as well be “I am justifying, therefore I am.” All I see is that I am, as I am justifying or I am anything (and even the “I” no longer matters in this seeing or this being).

I am is self-awareness.
It is mental reflection.

Thinking that I am does seem to be knowing that I am, and knowing that I am, while I am in the act of thinking seems to be knowing something that justifies itself in the act of “thinking justifying thoughts.”

So maybe I would say that, the “I am” reflection is self-justifying.

If by justification you mean words like “I am” that reflect or refer to an existing object, a referent, there being in the world in this case there being specifically here, being the “thinking justifications”. But I know that’s an outlandish statement here.

BUT, like a tautology, (which is what I think of the language of the stupid Cogito; “I am thinking = I am” is just as good of syllogism for my purposes as “I think, therefore I am.”), like a tautology it kind of makes sense that the “I am” reflection would be self-justifying. It literally fabricates a self.

An “I” just to be expressed.

You just helped me clarify what I mean by the Cogito. I see it as: the “I am” reflection.
That’s it. No “therefore”. I also recognize we could deconstruct “reflection” and there are always identity problems, but then I would be deconstructing, or identifying, and would come right back to the “I am” reflection.

give me an real world example — Metaphyzik

I did, you missed it, it's not going to help.

That there are green crows implies there are no new ideas. — Banno

I have not claimed that the cogito is meaningless. — Banno

So I asked you what does Descartes mean. And you said.

Well, I'm not at all sure - that's somewhat the point.

Some folk think he was making an inference.

Some folk think he was setting out an intuition. — Banno

If he was making an inference, then he was making or inferring. If he was setting out an intuition or intuiting, he was just the same.

Then you go right after the “I” further distancing from what I think Descartes meant, which is the “am”.

But I wish you would have answered my question.

We don’t have to know whether it’s an inference, or an intuition, or logical, or whether we can know, or whether I have a split personality such that the “I” in “I am” starts us off on a bad foot. When you attempt to empty the “I am” reflection you have already moved past what the reflection means, moved on to where you “are emptying”, and you find again “I am”.

Enoah above said the am “is-ing”. That’s meaningful here. The inference or reference, is an act. The intuition is of intuiting. The content doesn’t matter anymore. Inference and intuition distract as much as the I who might infer or intuit.

Thinking “I am” already happened when it is happening.

So sophistry is the logic?

That is a game and you know it haha. If you really believe in green cows (or think that is a justification for your arguments) you have a few screws loose.

Anyways when you feel like being honest let me know. You can’t provide a real world example because your argument has no epistemological foundation… else you would provide it.

Just an aside, I don’t mind your intransigent. It’s refreshing. So I know you can accept a rebuttal. As can I.

A very poorly considered diagnosis; some were never in the mire, and others never left it.

Actually, it's ~(p→ q). — Banno

And those are logically identical, in this case, correct??? Haha

p -> -q. Is identical to ~(p-> q)

And some were struggling to get out, only to be pushed back in...

:wink:

I actually think it's a great opportunity. What we have here is someone who is *perfectly* wrong - I dare say there's very few things that are more provable on this forum, very few debates that are more explicitly settlable, then "Does P implies Q mean notP implies notQ?" Corvus APPARENTLY believes in logic, he's not in here saying "logic isn't useful / logic doesn't make sense / logic is a government trick", he believes in logic, he's just completely wrong about it.

Which makes it a fantastic little experiment, I think. Can you use logic to prove to someone that they've lost their grasp on logic? I think that's a wonderful question. No better opportunity to test it than here.

To backseat drive a bit: I think a key area is the 'you don't know how to apply logic to specific cases and I do.' My wording, perhaps unfair, of something I have seen Corvus assert a number of times. I think that needs to be explored. Is he saying that the rule is being misapplied when it comes to the cogito? Why there? Also, it seems sometimes like a concession that his rule isn't a rule, and we can't use it in general, but in the case of the cogito it is, according to him, a good argument against it AND it is appropriate given the nature of the nouns involved. However, at other times it seems like a rule considered fallacious in logic is being argued by him as universally correct. Teasing out what is going on there seems like a core issue. Perhaps a period of just asking after clarification and greater explication would be useful. IOW intead of objections to what seems fallacious, piece by piece, accepting for the moment such things as information about his position and then asking a lot of questions: are you saying this holds in all cases? Are there examples where this is not the case? You've said I/we don't understand why the cogito in particular is problematic and so this rule of logic applies. Could you give other examples? What is the rule for these examples that makes them exceptions or the criteria? And so on. Likely my backseat driving is based on missing where this has been done and is unwarrented. But given how intractable the disagreement has been so far, I thought I'd throw out a suggestion. Apologies in advance for all the ways this is obnoxious and likely underinformed - and yet I am doing it anyway, knowing this, which is even worse on may part.:joke:

not exactly, but almost, sort of.

If you analyse the truth table of ~(p implies q) , it's only true when p is true and q is false.

Which is the same truth table, not as (p implies not q), BUT (p implies not q) and (p). So I think you're half right, but you need that "and p" to complete it.

https://www.umsu.de/trees/#(~3(p~5q))~5((p~5~3q)~1p)

Of course the frustrating part is, in natural language when someone says "it's not true that p implies q", they're not actually saying "p and not q", they're usually saying "p and q don't have that relationship, maybe no relationship at all".

Like if someone says "You're a virgo, that means you have a small brain", and you say "that doesn't imply that", you're not saying it means you're a virgo and you DON'T have a small brain, you're saying there's just no relationship between those two variables. Classic logic doesn't capture that well, it seems to me.

This is one of those instances where it's clear that natural language reasoning can diverge from symbolic logic.

Any logic text you choose.

That's kinda why I have been backing up and checking what I have writ with the tree generator.

(Edited - I assumed the wrong author) — Banno

Logic books? That's a poor logic of you again. If someone with poor logic or weird mind wrote some logic books and published (anyone can publish books by themselves via amazon these days), and if you happened to pick one up and read it, then you would believe in whatever is in the book.

You got to use your own loaf. Of course you read the books, but you must be able to apply the logic into the real life examples not parroting away what you read or seen.

I have thought this again, but it is clear what I say is correct. It is simple, but you don't see it for some reason.

(t -> e) -> (Not t -> Not e) This is via the contradiction reasoning.
This can be replaced with
T -> E
E = False
Therefore T = False

This is nothing to do with (t -> e) -> (Not t -> Not e) doesn't follow of your logic.
When you are applying the contradiction principle, it gets applied to both T and E.
Not just E or just T.

I am going out now, and will be back later. Would be interested in what you got to say about it.

That's kinda why I have been backing up and checking what I have writ with the tree generator. — Banno

The tree generator you keep brining in doesn't deal with applying the contradiction reasoning. It just generates trees and checks for validity. It cannot tell you a formula is true or false mate.