A discussion on Denying the Antecedent
Reply to Corvus
I would like to have a discussion with Corvus about if the logic used here is actually logical, or if it is perhaps fallacious.
Much later in that thread, it was acknowledged that it's not Modus Ponens, so we can agree on that. So if it's not Modus Ponens, the remaining question I had was, can you, in general, go from a statement of the form A -> B to ~A -> ~B - the answer to this is still up in the air, so that's the next thing to clarify.
Corvus, can you go from any statement of the form A -> B to ~A -> ~B, OR are there statements of the form A -> B where you can't reasonably go to ~A -> ~B?
Or, more succinctly, does (A -> B) -> (~A -> ~B) all the time, for all statements of implication A -> B?
I believe we can resolve this.
I would like to have a discussion with Corvus about if the logic used here is actually logical, or if it is perhaps fallacious.
Much later in that thread, it was acknowledged that it's not Modus Ponens, so we can agree on that. So if it's not Modus Ponens, the remaining question I had was, can you, in general, go from a statement of the form A -> B to ~A -> ~B - the answer to this is still up in the air, so that's the next thing to clarify.
Corvus, can you go from any statement of the form A -> B to ~A -> ~B, OR are there statements of the form A -> B where you can't reasonably go to ~A -> ~B?
Or, more succinctly, does (A -> B) -> (~A -> ~B) all the time, for all statements of implication A -> B?
I believe we can resolve this.
Comments (159)
If you disagree, it would be appreciated if you expressed briefly why but, ideally, exited the thread after that to avoid too many overlapping debates and confusion.
If corvus has other preferences, I welcome him to express them and hopefully they can be accommodated.
If it rains, then the ground will be wet. (Premise to prove)
R -> W
If it doesn't rain, then the ground will not be wet. (Inference = WHY NOT??)
Not R -> Not W
At this moment, you check to see if it rains, and if the ground is wet in reality.
It doesn't rain, and the ground is not wet. (TRUE from the inspection and observation)
Not R -> Not W = True
Therefore If it rains, then the ground will be wet. (True)
R -> W
Therefore for proving A->B is true or false, Not A -> Not B premise works fine.
You can use a proof based on the Truth table too.
R | W | R and W | R or W | R-> W | NotR | NotW | NotR -> NotW
T | T | T | T | T | F | F | T
T | F | F | T | F | F | T | T
F | T | F | T | T | T | F | F
F | F | F | F | T | T | T | T
Are there any exceptions?
Examples of a implies b where is not true that not b implies not a
If not sure, make up an extended truth table for all the possible scenarios, and see all the cases for the TF values. It gets apparent.
It either always applies, or it doesn't always apply. When you say you think I'm right, that means it always applies. But then you say it depends on the case. It either always applies, or it depends on the case, it can't be both.
But you can bring other assumptions as counter reasonings and inferences for the proof process. If not sure, make a truth table, insert all the TF values according to the rules. Ok, Later~
So any time you have (a implies b) , it's always true that (not a implies not b), you just don't always need to bring that up. Is that what you're saying?
And is the same thing true about the contrapositive? For every (a implies b) it's always true that (not b implies not a), correct? Even if it's not always useful to bring it up, it's always true?
If you look closely the truth table, it only ever contains P and Q cases with various connectives and extensions. You never see in the table H -> W, once it started with P, Q. It tells you that in an argument, you don't bring in some unrelated cases and argue, the logic is incorrect. That is just sheer nonsense.
If you started with H, G in an argument, then it only have cases with H and G in the truth table. That is the rule No.1.
Ok, we are going out for a meal here. I am not sure if it is under determinism or freewill. Have a good day, and talk to you later for any other points.
One thing at a time
So do you think any time you have (a implies b) , it's always true that (not a implies not b), you just don't always need to bring that up. Is that what you're saying?
Awesome, and this one?
And is the same thing true about the contrapositive? For every (a implies b) it's always true that (not b implies not a), correct? Even if it's not always useful to bring it up, it's always true?
An example where a implies b, and not b implies not a,
and an example where a implies b, but it's not true that not b implies not a.
I'm especially interested in the second example. The first example is very agreeable. The second is much more tricky, I think.
This is a pretty common example in logic textbooks, but it is not the case that if A -> B then ~A -> ~B. To see why, consider a lawn with a sprinkler system. A person sees it has not rained (~A), but then goes out to find the lawn is wet (B). This is possible because there are many ways for the lawn to get wet (B). If it rains, the lawn will be wet, but the lawn might also be wet for other reasons.
I know you disallowed hoses, sprinklers, etc., but in that case, when the only way for the lawn to get is from the rain (A), you should frame it as an iff/biconditional.
To get ~A -> ~B the starting premise would need to be "if and only if it rains (iff A) then the lawn will be wet (B),or A <->B. In such a case, B also implies A.
This would be "denying the antecedent."
But Corvus seems to be assuming an iff relationship, in which case the inference would be valid.
It's always valid (if not true), and that's called modus tollens. You're right about that, but wrong about modus ponens.
EDIT: Sorry I seem to have misunderstood flannel jesus! I thought he was agreeing with Corvus, but after a PM exchange it's clear that he isn't.
The argument was meant to prove R -> W, not (R or H) -> W.
If you wanted to prove (R or H) -> W, then yes of course, the premise should have begun with it.
For (P1 ..... Pn)-> W, you would need to go into Higher Order logic, wouldn't you?
We were trying to probe P1 -> W, but if you bringing in P31-> W, then you would be brining in irrelevant inference into the argument.
IFF must be regarded as presumed in the argument looking at the starting premise from the number of variables in the premise i.e. 1.
Do you have an example for this?
An example where a implies b, but it's not true that not b implies not a.
The ground is not wet, so it doesn't rain.
This is the case of contraposition isn't it?
It looks like it is sometimes true or sometimes not true.
Would it not depend on the checking over with the reality outside?
Did you check the truth table for it? I am not sure off hand without making up the truth table for it.
The ground is not wet, so it's not raining.
This doesn't seem like it depends on anything to me - if the first `if-then` is true, then the second `if-then` is true. In classical logic, given a statement of implication, contraposition is taken to be always true, not "it depends".
In classical logic, A -> B being true always means ~B -> ~A is also true.
They have the same truth tables as each other.
Sure, if the truth table says so, then it must be it. But in the empirical cases, you can also compare the TF values with the reality events, in which case if it is FALSE, then it proves the starting premise were FALSE.
So do you agree that, if one accepts a statement (A -> B), then according to classical logic one must always accept the contraposition, (~B -> ~A)?
What's an example where (A implies B) is true, but (~B implies ~A) is not true?
Even if it says True, when you compared with the real events, if they are false, then it is false. Also the premise is false.
I think classical logic very much has hard coded laws. Basic logic very much has hard coded laws. Logical proofs are a sequence of steps using hard coded logical laws.
https://thephilosophyforum.com/discussion/comment/889798
That's not based on logical laws, that's... what, then? Just some of your own personal reasonings based on your own personal relevant inferences?
Yes, or in other words: denying the antecedent of a biconditional is not a fallacy. Yet denying the antecedent of a conditional is a well-known fallacy.
You guys need to find a bedroom. I'm surprised we others are allowed to witness the proceedings.
"No, it is not logically sound to deny the antecedent in a bi-conditional proposition because it does not follow the rules of propositional logic. In a bi-conditional proposition, if both the antecedent and consequent are negated, the proposition as a whole is not necessarily true or false. It is important to consider both sides of the proposition in order to determine its truth value."
====
"No, denying the antecedent for a bi-conditional proposition is not a valid form of reasoning. In a bi-conditional proposition, if the antecedent is false, then the consequent must also be false. The only way to deny the bi-conditional proposition is to show that both the antecedent and the consequent are false."
=====
"Denying the antecedent of a bi-conditional proposition is logically unsound because it does not necessarily lead to the conclusion that the consequent is false. In a bi-conditional proposition, if-then both directions are linked together, meaning that if the antecedent is true, then the consequent must also be true, and vice versa.
For example, consider the bi-conditional proposition: "If it is raining, then the ground is wet." Denying the antecedent would result in saying "It is not raining, therefore the ground is not wet." However, the ground could still be wet for reasons other than rain, such as someone watering their lawn or a sprinkler system being turned on.
Therefore, denying the antecedent of a bi-conditional proposition does not provide valid grounds for concluding that the consequent is also false, making it logically unsound."
Creepily relevant.
It pleases me that the AI does not know what a biconditional is.
The post seem to be in an obvious case of internet info. snack gone down into wrong pipe.
In deductive syllogism it is fallacy, but in inductive case, it is not fallacy. Because the real life case can be contradiction to the premise.
Was just trying to be a help for the request from FJ for clarification.
So you would agree with the AI, and say that the falsity of the first half of a biconditional does not entail the falsity of the other half?
"The bi-conditional statement "if it is raining, then the ground is wet" is true because it goes both ways. If it is raining, then the ground will be wet. And if the ground is wet, it must have rained at some point. Therefore, the statement can be expressed as "it is raining if and only if the ground is wet," making it a bi-conditional statement."
I was quoting this from your post:
Quoting AmadeusD
As I noted, this is false because it mistakenly calls a conditional statement a biconditional statement. It also makes false claims about biconditional statements.
In the new quote that you provided in your last post, the reasoning is formally valid (except for the minor error in constructing the biconditional), but it is unsound given the fact that things other than rain can also make the ground wet, such as dew.
Well spotted Tim. I am a bit too lazy to be staring at Truth tables, and was too busy at the time, and was guessing. It depends on the TF values of p q in the table. There is nothing always.
Quoting AmadeusD
Quoting AmadeusD
Are about the same quote. In any case, I don't defend or criticise it.
I've adjusted my query, and had another version of it's defence, though:
"Yes, the statement "if it is raining, then the ground is wet" is a biconditional statement because it can be written as "it is raining if and only if the ground is wet." This means that if it is raining, then the ground must be wet and if the ground is wet, then it must be raining. Both conditions are necessary for the statement to be true."
https://truth-table.com/#(p?q)?(~p?~q)
Useful for those who are not too lazy to be staring at Truth tables.
So, this entire discussion devolves to something I used to teach freshmen.
Yeah, not the forum's finest hour.
Interesting!
It is common for llms to provide incorrect answers when asked to provide a conclusion in advance of providing an explanation, or without allowing them to think step-by-step. Here is how I tripped GPT-4, and how it recovered on its own:
Pierre-Normand
Hi GPT-4!
Is it logically valid to deny the antecedent in a biconditional proposition?
GPT-4:
Denying the antecedent in a biconditional proposition is not logically valid, and here's why:
A biconditional proposition can be represented as "P if and only if Q" (P ? Q). It states that P is true if Q is true, and Q is true if P is true. This implies two things:
1) If P then Q (P ? Q)
2) If Q then P (Q ? P)
Denying the antecedent generally refers to a logical fallacy in a conditional statement (if P then Q), where one incorrectly infers that if P is not true, then Q is not true. In symbolic logic, this fallacy is represented as: Assuming "If P then Q" (P ? Q) and "Not P" (~P), then concluding "Not Q" (~Q), which is invalid.
In the context of a biconditional, denying the antecedent would mean arguing that because P is not true, Q must also not be true. However, this doesn't hold because the biconditional also includes the reverse conditional (If Q then P). For example, consider the biconditional "You can drive if and only if you have a license." This means if you have a license, you can drive, and if you can drive, you have a license. Denying the antecedent here would be saying, "If you don't have a license, then you can't drive," which is true and follows logically. But this isn't a fallacyit's just an application of the reverse conditional (If Q then P).
So, in a biconditional proposition, "denying the antecedent" can lead to a valid conclusion if you're applying the reverse conditional correctly. It's essential to differentiate between denying the antecedent in a simple conditional statement (which is a fallacy) and applying the logic of a biconditional proposition, where both directions of implication hold.
Pierre-Normand
Indeed! So, interestingly, you began your answer with denying the logical validity of this form of reasoning but then, after thinking it through, correctly concluded that it is, after all, valid.
GPT-4:
You're right, and I appreciate your patience as we navigated through the intricacies of this topic. Biconditional propositions indeed add a layer of complexity beyond simple conditional statements.
To clarify, when dealing with a biconditional proposition "P if and only if Q" (P ? Q), denying one component does logically allow us to conclude the denial of the other, due to the nature of the biconditional relationship. This is because a biconditional asserts that both P and Q are equivalent in terms of their truth values; they're either both true or both false. Therefore, denying one (saying it's false) does indeed allow us to conclude that the other is also false, which is a valid form of reasoning in this specific context.
Thank you for pointing out the need for clarification. The nuances of logical reasoning in different contexts can lead to interesting discussions!
Pierre-Normand
What interests me is the reason why you spontaneously gave a wrong answer in the beginning of your response. My conjecture is that the superficial similarity of my question with the very commonly stated explanation (in your training data) of the invalidity of denying the antecedent (of a conditional proposition) tripped up the next-token prediction algorithm, as it were. While you proceeded with generating the rest of your explanation, the richer context thereby generated (by the tokens already produced) enabled the underlying language model to latch on the correct rational pattern and to correctly articulate your response in a way that that is contextually sensitive to the fact that the topic at hand was biconditionals rather than simple conditionals.
GPT-4:
Your conjecture touches on some of the complexities and subtleties involved in how language models like mine generate responses. When I receive a prompt, I generate responses based on patterns, structures, and information present in the training data up to my last update in April 2023. Your observation about the initial incorrect direction in my response could indeed be influenced by the prevalence of discussions around the fallacy of denying the antecedent in conditional statements, which are more common than discussions specific to biconditional propositions.
As I generate text, each subsequent token (or word) is chosen based on the context of the preceding text, aiming to form a coherent and contextually relevant response. This process involves a complex interplay of probabilities and contextual cues. In the case of your question, the initial framing might have activated patterns related to the more common discussions around conditional statements. However, as the response progressed and the context became richer and more specific to biconditionals, the language model adjusted to better align with the correct logical principles pertaining to biconditional propositions.
This dynamic adjustment is a characteristic of how language models generate text, striving for coherence and relevance based on the evolving context of the response. Your insight into this process highlights the importance of context in natural language understanding and generation, as well as the adaptive nature of language model responses as they unfold.
Oh wow, that's amazing that you're saying that.
In this post you call it a deduction - you use the word "deduces".
https://thephilosophyforum.com/discussion/comment/889798
So you were incorrect about that when you said that?
And then earlier in this thread you agreed with the following:
"So do you think any time you have (a implies b) , it's always true that (not a implies not b), you just don't always need to bring that up. Is that what you're saying?"
But since now you're saying it's a Fallacy, then the above quote that you agreed with can't be true.
But people have been telling you that for weeks already...
This is clearly wrong. I'll leave it there.
A better example to use is
I am running ? I am moving
Does «I am not running» ? «I am not moving»? The answer is evidently no. So from P?Q we don't have ¬P?¬Q. ¬P?¬Q is in fact the same as Q?P, which obviously is different from P?Q.
P?Q Everytime there is P, there is also Q
Q?P Everytime there is Q, there is also P
¬P?¬Q Everytime there is not P, there is also not Q; which is the same as saying that everytime there is Q, there is also P.
Edit: Sorry, I didn't see the thread was solved :-P
How is it wrong? This was stated about a biconditional statement. In a biconditional statement 'P iff Q', the truth of either P or Q entails the truth of the other one while the falsity of either P or Q entails the falsity of the other one. In other words, 'P iff Q' entails that either P and Q are both true or P and Q are both false.
Quoting Pierre-Normand
"This statement is logically incorrect because when one component of a biconditional statement is denied, it does not necessarily allow us to conclude the denial of the other component. In a biconditional statement "P if and only if Q" (P ? Q), denying one component does not automatically lead to the denial of the other component. This is because the truth values of P and Q are independent of each other in a biconditional statement, and denying one does not necessarily mean the denial of the other. So, it is not valid to conclude the denial of one component based on the denial of the other in a biconditional statement."
It is not entailed that hte denial of one requires the denial of hte other. I should have been clearer in my objection. It was clearly inadequate.
I haven't checked the logic yet, but I'm pretty sure you're exactly incorrect about this. P <-> Q does not mean they're independent, it means they always have the same truth value. Denying one always means the denial of the other. Affirming one always means affirming the other. Happy to prove it if necessary - with truth tables, or just using basic Modus Tollens.
The two initial snippets that you quoted and attributed to me were written by GPT-4, although I am agreeing with them.
Who is the author of the long paragraph between quotes that you posted above ("This statement...")? Was that authored by the free version of ChatGPT (hence GPT-3.5 turbo)? What was the context and the prompt? It rather sounds like GPT-3.5 when it is in the throws of a bad case of hallucination and has lost coherence after having done a reasoning mistake and thereafter attempts to justify its initial claim. (Note that many human beings behave like that too.)
But that's not what I was saying was wrong. I entirely misspoke in my objection.
Quoting AmadeusD
This seems to me something I can claim without knowing much formal logic (at least, not conversant).
"It has rained, and so my lawn is wet"
It is plainly true that denying your Lawn is wet does not entail denying that it has rained and vice verse. They are conditionally distinct. The only thing that requires the truth values to align in P and Q here is so. It's possible that what I'm outlining, without hte requisite knowledge to discuss it adequately, is that bi-conditional statements aren't a logically sound tool because we can look at the logic of a bi-conditional statement that appears sound, and it can be wrong.
This is not my utterance. Here's an interesting further response I got:
"I apologize for the confusion. Let me clarify:
In a biconditional statement "P if and only if Q" (P ? Q), the truth values of P and Q must be the same. This means that if P is true, then Q must also be true, and if P is false, then Q must also be false. So, in the context of affirming the components, the truth values are indeed dependent on each other.
However, when we talk about denying one component not necessarily leading to the denial of the other, what is meant is that if we deny the truth of P, it does not automatically mean that Q is false (and vice versa). The components are logically connected in a biconditional statement in the sense that they must have the same truth value, but denying one component does not automatically imply the denial of the other."
I believe the difference I'm seeing is between assertion and assent. It seems fully wrong to me that you can assent as a result of assertion, without something (other than triangle of dots) between them.
Quoting Pierre-Normand
An AI. Which also, when i pushed further, said this:
"So, in a biconditional statement, if you affirm Q, then you must also affirm P, and if you deny P, then you must also deny Q in order for the statement to be logically sound. The truth values of P and Q are interconnected in a biconditional statement, so they cannot be affirmed or denied independently of each other. Thank you for pointing out the inconsistency in my previous responses."
So, my objection isn't to the logic, it seems. It's to the application. The logic clearly fails in many cases.
Ah my mistake, it was in quotes. But you still ended your post with
Quoting AmadeusD
Do you still believe that? I believe those were your words.
The only one I've been able to stand behind is that bi-conditional logic isn't relevant to real life, in most cases.
If you're saying that the logic fails in many cases, then you are objecting to the logic. If your issue is with the application of the logic to a particular case, then you may be claiming that the logic (e.g. the affirmation of the consequent in the context of a biconditional statement) doesn't adequately capture the form of the argument that someone made in this particular case.
Also, if someone were to claim that the lawn is wet if and only if it rained and that therefore, since the lawn is wet, it must be the case that it rained, you can object to this conclusion on the ground that there are other reasons why the lawn might be wet. In that case, you are not objecting to the validity of affirming the consequent in the context of the (true) biconditional premise "the lawn is wet if and only if it rained." Rather, you are challenging the soundness of the argument. That is, you are taking issue with the truth of the biconditional premise. You are saying that "the lawn is wet if and only if it rained" is a false biconditional statement.
I think I tentatively agree with that, sure.
= fails.
Quoting Pierre-Normand
It is. They are obviously, patently, inadequate. They neither capture the nuance of reality, or justify their relation. It is a nonsense.
It's not nonsense. It's just false. Logic deals just fine with false statements. Someone who would have made the wrong inference that it must have rained could have overlooked the fact that the sprinklers could also have made the lawn wet. (Overlooking that is not nonsense either.) They did not commit a logical fallacy like affirming the consequent of a conditional premise. They merely reasoned (validly) on the basis of a false biconditional premise. Incidentally, do you know the difference between the soundness and validity of an argument? Understanding this difference is quite relevant in the context of the present discussion about formal logic and its applications.
Is that a fallacy?
No, it's not. I misspoke. Thanks for catching that! I meant to say that affirming the consequent of a conditional statement is a fallacy. My brain's next-token prediction algorithm must have misfired. (I've edited the post to correct this.)
I seems to be the case your whole point was not trying to find and learn something in logic, but trying to assert my one post was wrong. Is it that meaningful to you and to the rest of the world?
I can say anything I feel correct. Whether you agree to it or not, that doesn't make anything different. After all the whole of you point seems to be dependent on the internet searches and some other folks agreeing with you. My point is more trying to learn something in Logic. I am not really bothered if what who said was wrong or right, as long as I learn something. I am not here to prove you are right, and I am wrong, or I am right, or you are wrong. If that was your ultimate motive for privately messaging me with the point, then I am a bit disappointed with your stance. Give it a rest, and move on. There are even some folks complaining that the posts that you spew out are hurting his eyes.
I'm not hiding my intentions. I'm not being secretive. I've been very straight forward and transparent.
No one said you were secretive. But once the points were made in the posts, you could sit and think for yourself, and get the points if your intention was to learn something. You didn't have to keep on going drumming up the crowds for claiming right or wrong on someone's idea, after all what was passing trivial comment in a post. It just feels there is very little point in the bizarre attempt of the repeating the same thing, and from learning point of view.
My point was that if the case was Deduction, then denying antecedent is fallacy (that is what internet says), but if it is Induction, then denying antecedent is not fallacy. Did you take that into consideration?
I don't know why you suddenly seem so hostile to me here, we've acccomplished the goal we set out to accomplish. I'm happy about it. Are you not?
There is nothing wrong for someone to be wrong. People keep learning and changing their views and ideas. If one was right on a point, that doesn't make him a teacher or the greatest philosopher in history. Important thing is, that one keeps learning and improving one's knowledge.
There's nothing that's unclear hear. You made a bad argument, you were cocky about it, you were a jerk about it when people told you they disagree with your argument, and now you've finally seen that you were wrong. You were a jerk, and you were wrong. There's not a whole lot more to say about it.
What has happened in this thread is a microcosm of what I warned about in your own thread. @AmadeusD put his trust in ChatGPT and because of this came to believe logical fallacies. Like a human, ChatGPT made an error and recovered from that error without ever admitting that it made an error, and AmadeusD follows it almost step-by-step. Heres what I said:
Quoting Leontiskos
So there's something for you to learn about variations in human nature.
Gaslighting is strongly associated with narcissism.
Please note this point. The internet says "It is fallacious to deny antecedent." But it is only fallacious in deductive syllogistic case. We have been talking about an inductive case. It is not fallacious to deny antecedent in inductive logic.
What do you think the word "deduce" means Corvus? What relationship do you think there might be between "deduce" and "deductive logic"?
No, but it is perhaps an instructive hour. We witnessed two individuals who are extremely confident and yet demonstrated that they do not understand even the most elementary logical inferences (@Corvus and ). This is a good reminder that the following thought cannot be taken for granted, This is a philosophy forum, therefore everyone meets the minimum level of logical competence. There needs to be better handshaking; a more cautious appraisal of the interlocutors competence. If this is not done then a great deal of time will be wasted on everyones part.
Quoting wonderer1
Eh, the case could be reasonably made that this correction should have occurred in private.
It must be still winter chill season in England.
I understand deduce as logical thinking from A priori or analytic concepts. Induction means that you come to logical conclusion via external empirical observations.
Here is a question for you. Is "I think therefore I am" a deductive or inductive statement?
How about "If it rains, the ground will be wet." ????
That's right, which is why you calling that logic inductive reasoning just doesn't make a whole lot of sense to me.
Inductive reasoning looks like this:
Sue's car is already here every morning when I arrive, so her shift probably starts before mine.
Inductive reasoning does not look like
a -> b
~a
therefore
~b
It's obviously fallacious deductively, but I haven't seen any good reason to think it's a good argument inductively either - or an inductive argument at all! Where's the induction? Where's the external empirical observation?
See? We don't even agree on the statements were deductive or inductive, and were trying to argue if they were true.
It is intended as deduction. It's not, I was thinking and hey, look I was also existing. Then I tracked many instance of thinking and existing was happening, so it's probable that they are connected causally or something like that.
Descartes was saying given that I am thinking this presumes I am. I could not think if I did not exist. It is part and part with ANY COGNITIVE ACTIVITY at all or any action on my part.
One can get into the issue of whether the 'I' is getting snuck into his deduction, but it is NOT deductive argument and 'therefore' is a term talking about logical inference and not at all suggesting that thinking leads ontologically to being. Nor is it asserting that thinking causes existence.
And if you thought it was about deduction why in goodness name did you spend so much time calling it Modus Ponens, which is deduction? And even when you finally acknowledged that it wasn't modus tollens, did you continue to write deduction symbolic logic rather than using inductive reasoning.
And then why would you go into Flannel Jesus's motives, when it is so clear that being not wrong has led you to the most circuitous avoidance and distractions now in two threads.
Someone else could potentially chastize FJ for pursuing this, but it makes not the slightest sense for you to.
Further, if he thinks you are wrong, but you can't see it or admit it, then the issue is not closed. He can continue to wonder (against great odds) if he missed something. And when asked, you can say whatever that is.
That whole line was just gaslighting.
Right, we don't agree because you're just choosing not to understand things. You literally used the word 'deduce'. Of course we don't agree if you've just decided you're going to disagree - it's free to just contradict everything, it takes no effort to just say "that's wrong, that's wrong, that's wrong". But the word 'deduce' has a meaning, and your provided logic *clearly* doesn't involve any induction.
Inductive statement means that both premise and conclusion are based on the empirical events or facts.
Right, which makes it once again clear that it's not an inductive argument. How are you going to make an inductive argument with no reference to any empirical observations?
That is still to be discussed and concluded. I am not sure 100% that is inductive or deductive statement. To me it is not a statement. It is grammatically incorrect to begin with.
I think~ has no content, no object. We don't know what I think means.
Who is "I" there by the way?
It is a psychological statement. It is not deduction or induction. I have said that many times, but obviously you missed it.
I have tried with the different methods for logical analysis, which didn't suit the cogito for a logical analysis due to the fact it being a psychological statement. So the final conclusion was throwing out cogito into the bin for being a solipsistic subjective statement which is not fit for logical analysis.
Sure, it just shows your whole mental operations and judgements are based on your volatile emotions and wild imaginations rather than facts and reasons.
That is definitely an inductive statement. It is never deductive statement for sure. The statement came from your experience and observations in the past. You clearly have no idea what deductive and inductive thinkings are. Herein seems to lie all the confusions.
Just more gaslighting.
It was just to point out that comment was emotionally volatile in nature, which totally disregards the facts or logics.
Says it all :roll:
Projection, anyone.
Isn't it the first principle on which philosophical discussions are based? Freedom of thinking and expressing on what you think is correct on the subject? Do you condone dishonesty, pretension and uncontrolled emotional volatility in the discussions?
There isn't much to instruct here. Not because there is no topic, but because there is no student. See the 100% certainty thread.
There is not much helping people who don't want to understand. Descartes invited us in meditation by writing His. Some people don't want to meditate, but instead want to autistically analyse the text to find syllogistic flaws, not knowing that language does not exhaust thought and there is only so much logic can do for them but perhaps they have "aphantasia".
There is criticism to be given to Descartes, but his philosophy does have a solid system.
The most common criticism to Descartes besides naïve realism from people who can't conceive hypotheticals, is extreme, unbounded skepticism (such as doubting that any action requires existence). Those who do that however, are not willing to face the consequences of their unbounded skepticism. Either they do so, or accept Descartes argument. But they want to have the cake and eat it.
When it amuses. Keep going. :cool:
:rofl:
It was a simple and straight forward question to yourself, since you publicly objected to one's free thinking and speaking what one feels correct on the philosophical topics.
You clearly do. Look at this post by you.
https://thephilosophyforum.com/discussion/comment/894247
You chose to group the quote like that, instead of how it should obviously be grouped in my original post
Quoting flannel jesus
And then I said
Quoting flannel jesus
So why did you do that? Why did you group the wrong parts of my post together, in order to criticise me for something I didn't say? Why are you dishonest?
and viewed as a meditation or exploration it's very interesting. I'm certainly not critical of Corvus' behavior because he's skeptical about the cogito. I'm skeptical about the cogito. Though I'm not skeptical because denying the antecedent shows there's a problem or some of his jumping from deduction to induction and pretending he was using induction all along. I think the problem with the cogito is that it allows for an assumption, at least potenially of the 'I'. But this has been said by others and in greater detail. But I don't think that makes it useless or simply wrong. Someone needed to do what he did and it's easy to post-Descartes take shots at it.Quoting LioninoI think this is often true. Being unconvinced is safer ground than mounting arguments that demonstrate one's skepticism is correct. There's a lot of fruit of the poison tree in philosophy forums.
Though if we view these also as exploratory, they can be a fine part of a discussion.
The questions wasn't for you. It was for jgill. You said that you wanted to learn about Logic, and asked for my help, hence I tried. Jgill didn't seem to have a clue what he was talking about, so asked him a question on what he said. None of your business.
I asked for your help to learn about logic? Are you sure that's what I said?
But this emotionally fuelled carry-on is just waste of time. There is no meaning or point to talk with you or any of the folks in your bandwagon. Bye.
You haven't shown the least bit of competency in logic. I'm sure I have a lot to learn about logic, but not from you. If I ask someone to teach me stuff about logic, they'll have to know what "therefore" means as a bare minimum.
Our agreement in your private message was to put it across to OP, so some other Logic expert could help us. I never claimed I was a logic expert.
But instead of that happening, you kept on claiming I was wrong, and the folks in your bandwagon joined in to make senseless emotional ad hominem comments with rolling eyes and gaslighting statements.
So I just concluded that it would be best we leave it there, and go our own ways. It would be better time spent to engage in some other topics with the likely minded folks or just do some readings??? I will leave you to it. I tried my best to help you. But perhaps it didn't work out as we intended at first. We can always learn from all our doings, sayings, hearings and readings. ATB~
Inductive reasoning is when the conclusion doesn't necessarily follow from the premises but is nonetheless reasonable to infer.
For example, "if you don't stop shouting then I am going to turn the car around" doesn't necessarily entail that if the children stop shouting then the mother won't turn the car around, but it is nonetheless a reasonable inference. As such it is a case of inductive reasoning.
I do, lmao. You spent pages telling me I can find that modus ponens allows for denying the Antecedent in any basic logic book - you obviously thought that was a valid step in deductive reasoning. That's what basic logic books about symbolic logic are about - deductive reasoning.
You literally used the word "deduce". You criticise other people for being dishonest, but I can't see an ounce of honesty from you. The argument you provided is not an inductive argument. You said inductive arguments are about evidence from observations - not a word of the argument in question was about evidence or observations.
You don't have any kind of instinct or intuition for what logic actually looks like, how logic actually works. You said you'd go back and read one of your logic books - I think you'd really benefit from that.
You misquoted him, and then you referred to this misquote as what led to your discovery he didn't understand. This was pointed out to you, and you seem to have opted not to actually check this. You seem emotionally volatile, but I do think you have the right to say what you feel is correct, even when you are this obviously confused or disingenuous.
@Corvus
(A -> B) -> (~A -> ~B) is false. "A -> B" is not biconditional implication (i.e., IFF): it means that if A is true, then you can infer B is also true.
If A is false, it is entirely possible for B to be true; because all you know is that when A is true, B is true but not that B can only be true when A is true.
To prove this, flannel jesus, you would need (A <-> B) -> (~A -> ~B).
Yes, this is entirely correct
You keep repeating to the others the word by word what the others described your writings.
Good point Bob.
Thanks for your advice. I read a Logic book once long time ago, and am back to reading another one now. I am enjoying reading it. I wish you all the best.
We have agreed to move on. Just wondering what your point is keep repeating the others' sayings word by word.
Quoting Corvus That's a good thing to wonder about. I notice that for the second time you have referred to this instance as a pattern. That I do this with others' sayings. I did it with two things you said. I reassured you that my being critical of what you are doing here does not mean I think you can't write what you feel. Obviously, given your reaction it makes sense to specifically address your concern in your words. As far as the emotional volatility accusation you made It was not a saying, it was a judgment and not in the form of a saying. My aiming it back at you was to show how easy it is to claim that someone is being emotionally volatile. Rather than, for example, deal with some of the factual issues in that post. But, of course, you are free to ignore anything troublesome, just as you are free to not check to see if you misquoted Flannel Jesus. You're free to never show the logic book that showed your deductions were correct. You're free to claim you were always doing induction, despite the obvious deduction symbols you used. You're free to make up things about Flannel Jesus and me. You're free to do all sorts of things and I would defend your right to keep posting here, if the subject ever came up. If you want to move forward, well obviously you are free to move forward, whatever it says about your character.
I'll also move forward.
When it is a deadlock, one has to say "Hey let's move on", and that's what I have done, and you still keep accuse the position I took.
I don't need your nonsense and emotion filled writings. I have moved on long before you head butted into the thread with your nonsense. As I said, was just wondering what you were on about. Move on mate.
Quoting wonderer1
In retrospect it isn't courage that is lacking, so much as integrity. Seemingly, it's so easy to say, "I didn't know what I was talking about.", but seemingly impossible for Corvus.
In any case, I thought you were moving forward. I am, in any case. I'll be ignoring you. I suggest you actually move forward yourself. Perhaps we'll have a lovely interaction on some other issue after a break.
Take care.
Neither did I trust, nor use ChatGPT. lol. Quoting Leontiskos
I didn't come to 'believe' anything.
Quoting Leontiskos
No one thinks this. Half the people here(including me, even in this exact case) note clearly and honestly what they are not ept in various ways. I actually told you, categorically, I don't know formal logic and stand behind nothing i posted.
What I think the forum needs is a reduction in the onanist tendancies of the self-obsessed in talking down to other forum-goers just trying to figure shit out. The immense failure of your comprehension in these comments leads me to think I am talking to closed ears, though.
To clarify, the fallacy of denying the antecedent applies strictly to conditional statements (P ? Q). That is, from "If P then Q" and "¬P," one cannot validly conclude "¬Q." A classic counterexample:
However, in the case of a biconditional (P ? Q), the reasoning changes because P and Q must always share the same truth value. If P is true, Q must be true, and if P is false, Q must also be false. This is captured formally by the tautology:
(A?B)?(¬A?¬B)
This expresses that if A implies B, then ¬A implies ¬B, which holds true only when A ? B (i.e., a biconditional). This is why, in a biconditional statement, denying one side allows us to deny the other.
For those who want to see this logically broken down, here's a truth table visualization:
https://truthtablegenerator.org/#(A?B)?(¬A?¬B)
Its important to be precise when discussing logical fallacies, as they depend on the exact logical structure in question. Hope this helps clarify!
If it's raining, the ground is wet, he said. A fair enough implication, no reason to reject this.
Then he says, therefore if it's not raining, the ground is not wet.
The man completely forgot that there's other ways for the ground to get wet. Maybe the sprinklers were on, maybe someone just watered the lawn.
So what corvus failed to realize was that, if a implies b, that doesn't always mean not a implies not b. That's why his thinking is terribly fallacious.
That was an excellent first post. I could learn a lot from you.
Sorry, I'm not sure what you're talking about buddy.
Your description seems to be based on the classical logic. Have you read about Relevance Logic and also the Entailment Logic, which use axiomatic proofs in the inferences?
I am going to keep it short, and if you want further discussion open a new thread on the topic, and I will engage with you, since FJ is one of the interlocutors I don't engage with on any philosophical topics.
You can read this article, if you are further interested on the topic before opening a new thread.