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

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.

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.

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)

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?

I am just trying to understand your logic here. — Corvus

It's not just my logic.

Sure. So the obvious conclusion is that there is no consistent account of the nature of god as posited.

Now from this we might conclude either that he doesn't exist or that he does and we just have to accept that he is inscrutable.

You get to choose.

No, because if you are able to get through to Corvus, observing how you did so might provide me with insight that I don't have at present. — wonderer1

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. A tragedy in which we are all implicated.

We were moving on a bit, until became involved, leading us back into the mire.

It is not about follow, it is about introducing assertion and inference. — Corvus

Yes, Follow.

Are you still claiming that when you stop thinking, you cease to exist is true? — Corvus

No, Corvus. That is your confusion. I have never claimed that when you stop thinking, you cease to exist. What I have said, quite explicitly, is that if Descartes' argument is that if you are thinking, you exist, then that this does not, as you have claimed, imply that if you stop thinking you cease to exist.

I have also attempted to show you that your argument would hold if Descartes' argument is that by definition "I" am the thing that is doing the doubting. This is your out; but it seems you have difficulty seeing it.

You bite the hand...

Are we now playing "posts last wins"?

Hoping to be edified. — wonderer1

Why - because that would be entertaining?

, from "If it thinks, then it exists" it does not follow that "If it does not think, it does not exist".

And from "If it rains, the ground will be wet" it does not follow that "If it does not rain, the ground will not be wet". I can hose the ground, and rocks exist without thinking.

I recommend sitting back and observing whether or not Banno can get through to Corvus. — wonderer1

It seems not, but

Are You Not Entertained? Is this not why you are here?? — Maximus, and Banno

You're just going on and on with a strawman that no one who takes biblical critical theory seriously would take seriously. — Hanover

Quite right. The religious need scholarship in order to make their scriptures palatable, even unto themselves.

Ok. This is why we can't have nice conversations on these forums.

...which makes (t→e) False too. — Corvus

No, it doesn't.

You have been battered about this for a few days now, and it is difficult to back down when you make a mistake, even in the most friendly circumstances.

But I really do have to go water the garden. You see,

If it rains, then the ground is wet.
It doesn't rain.
The ground is not wet.

and

If I don't hose, and it doesn't rain, the ground will not be wet

But

If I hose, the ground will be wet.

All I did was remove "Hence". That's were you went astray.

How is it tell you nothing? — Corvus

Because (t→e) can be true and yet (¬t→¬e) either true or false.

He thinks implication is equivalence, it seems.

I have to go water the garden. It's not going to rain today.

That whole conversation is an exercise in missing the point... — Fire Ologist

So you are certain of the Cogito without any justification?

Of course I deny its Truth. It is FALSE. — Corvus

It's not false - if by that you mean that it is a contradiction and false for every interpretation.

(t→e) tells us nothing about (¬t→¬e).

If you don't think, you don't exist. Is this not False? — Corvus

There are things that... and here one needs a free logic... that don't exist and don't think.

But you have gone off on a tangent, I asked if you would explicitly deny that (t→e)→(¬t→¬e).

I can coherently deny any sense data, like reading “this post”. — Fire Ologist

You replied to the post. Now you would deny that there was a post, and supose this to be somehow coherent?

I have not claimed that the cogito is meaningless.

I commend On Certainty to you.

I don't know what you are asking. Shouldn't that be (¬t→¬e) → F? Which is not valid, as shown by the countermodel.

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

I gather (¬t→¬e) = F is to be understood as "(¬t→¬e) implies the false"?

No, it doesn't. Countermodel: Rocks don't think, but exist.

But you see that even a simple logical formalisation and reasoning of Cogito, proves it is false. — Corvus

You have not shown this.

Whatever. Flogging him repeatedly is tiresome.

If one is carefully considering whatever may exist, once one comes to be considering one’s own existence, one finds something existing that one can’t deny. — Fire Ologist

Notice the "if...then" in that? If what you say were so, someone ought be able to set the argument out formally.
If (one is carefully considering whatever may exist) and (one comes to be considering one’s own existence) then (one finds something existing that one can’t deny)

One can find all sorts of other stuff that one cannot coherently deny - like that you are reading this post. So if that is our standard, the Cogito is hardly special.

You think you have proved it false, but you apparently use an invalid argument.

Others here claim that it is true, and indubitable, but offer no support for that contention.

It would help your standing immensely if you were to explicitly reject the argument that
(t→e)→(¬t→¬e).

Well, blessed is just about everyone with a vested interest in the status quo, as far as I can tell, Reg. — Francis, LOB:3

You're denying what is explicit in the text. No citation will help you.

God said, 'Take your son, your only son, your beloved Isaac, and go to the land of Moriah, where you are to offer him as a burnt offering on one of the mountains which I shall point out to you.'
— 22:2 — Banno

Unconscionable.

The interpretation I offered that interpreted the story as offering opposition to child sacrifice isn't a new fangled liberal interpretation — Hanover

I didn't say it was. I said it suits our more liberal times. In other times it was no doubt understood as showing how a vassal must obey their lord. Nor are the various interpretations mutually exclusive. It can be an admonition both to obedience and against human sacrifice.

But in no reasonable reading could it not be understood as advocating that one ought do as god commands even if what is commanded is abominable. That one's own desires is to be secondary to God's will.

Thank you Rabbi Banno for that comprehensive and contextualized analysis. Thousands of pages and hundreds of years of interpretation crystallized. — Hanover

An ad hom already. That was quick, even for you.

But he did screw with Abraham’s head and majorly gaslighted Job in the pursuit of “testing” their loyalty. — schopenhauer1

Which is at the least good evidence that the god described in such books is not worthy of praise for his morality.

Biblical interpretation has to be contextualized — Hanover

Hmm.

Well, obviously, this is not meant to be taken literally. It refers to any manufacturers of dairy products. — Gregory, Life of Brian

For God to be an ogre demanding obedience, you have to take a very literalist definition and you must assume he decrees without being subject to interpretation. — Hanover

Or you could read what he supposedly says and does in your text.

God said, 'Take your son, your only son, your beloved Isaac, and go to the land of Moriah, where you are to offer him as a burnt offering on one of the mountains which I shall point out to you.' — 22:2

Pretty hard to misinterpret the obscenity here.

ust trying to analogize looking at the logic of the words before addressing the meaning of the statement. — Fire Ologist

Whaat does that mean - that we need a predicate logic? I offered that already. Have you an analysis that shows the validity of "I think, therefore I am"?

banno saying he isn't certain of it. — flannel jesus

To be sure, that is not what I am saying; but that certainty of my existence is not dependent on the cogito. Further, I suspect your exist was undoubted long before encountering the Cogito.

Why do you want to prove (t→e)→(¬t→¬e) is equivalent to A <-> B? — Corvus

I don't, since it isn't. And that was directed at

I can prove it — flannel jesus

That doesn't mean much — flannel jesus

I don't think it's trivial — flannel jesus

Make up your mind! :wink:

I'm out, I think. Too tired to think.

(Which can be seen in what I just wrote...)

It shows (I hope...) that your

(t→e)→(¬t→¬e) isn't itself equivalent to (t↔e), it's equivalent to saying "if you have an implicaation (t→e), it's safe to say (t↔e) — flannel jesus

is valid. If trivial.

I slightly misstated the argument. — flannel jesus

Fine.

If (t→e)→(¬t→¬e) holds, as a general rule, then all (t→e) are actually (t↔e). — flannel jesus

But...

Go on, then. Here is the premise:

P - > Q — Corvus

or in my parsing

(t→e)→(¬t→¬e) — Banno

Show how that is equivalent to A↔B.

it's equivalent to saying a <-> b — flannel jesus

No, it isn't.

What do you think his argument is? — Janus

I'm not going over that again. Time to move on. Corvus is wrong, but perhaps not in the way folk have suggested; and that he is wrong does not imply that therefore the Cogito is valid.

...where does that premise come from? — flannel jesus

The premise is invalid. But it is not a contradiction. That is, it seems possible. (But it has been a long few days and I may be wrong).

@Corvus' logic has been less than impeccable - we all make errors. But again, while he has not shown that the Cogito is invalid, no one else has managed to show that it is valid.

I don't know how to do that any further than I already have.

P = I think, therefore I exist.
Q = I don't think, therefore I don't exist. — Corvus

P= (t→e)
Q= (¬t→¬e)

The first assumption:

P - > Q — Corvus

(t→e)→(¬t→¬e)

I can't see how to make that any clearer.

It's not easy to see what you're saying here. It looks like you're saying

(t→e)→(¬t→¬e)

Is equivalent to saying

(t→e) — flannel jesus

Only if you misread what is writ.

I certainly did not write

(t→e)→(¬t→¬e) ↔ (t→e)

That's invalid.

Indeed, I am not saying anything of that sort, but pointing out that the argument Corvus uses appears valid.

I think an equivalent of 'I think therefore I am' is 'If I am thinking, then I must exist". 'If I am not thinking then I must not exist' does not follow, but 'if I don't exist, then I must not be thinking' does follow, as far as I can tell. — Janus

Ok, so

(t→e) ↔ (¬t→¬e) is invalid.
"I think therefore I am" is not equivalent to "I don't think therefore I am not".

And
(t→e)↔(¬e→¬t)
"I think therefore I am is equivalent to "I'm not, therefore I don't think"

But this is not the argument @Corvus presented in the quote.

your proof is treating (t→e)→(¬t→¬e) as a premise. — flannel jesus

Here's the argument quotes:

P = I think, therefore I exist.
Q = I don't think, therefore I don't exist.

P - > Q
Not Q (Q is FALSE)
therefore Not P (P is FALSE) — Corvus

(t→e)→(¬t→¬e) is a premise. it's P->Q.

Also,

The logically entailed negation of 'I think, therefore I exist' is 'I don't exist, therefore I don't think' not 'I don't think therefore I don't exist'. — Janus

t→e negated is ¬(t→e))


but

¬(t→e) ↔ (¬e→¬t) is invalid, and
¬(t→e) ↔ (¬t→¬e) is invalid.


¬(t→e) ↔ (¬e∧t)?
(fixed link)

I was going to agree, but...

Editing post now I have time to take a look...

t=I think
e=I exist

P = I think, therefore I exist — Corvus

t→e

Q = I don't think, therefore I don't exist. — Corvus

¬t→¬e

And the syllogism is...

P - > Q — Corvus

(t→e)→(¬t→¬e)

Not Q — Corvus

¬(¬t→¬e)

therefore Not P (P is FALSE) — Corvus

⊢~(t→e)

Giving
(((t→e)→(¬t→¬e))∧¬(¬t→¬e))→¬(t→e)

Which is valid.
Check my working.