Debate: Person A vs. Person B on Claim X

[jostpuur]

I've seen this happening several times. Person A and person B debate about some claim X. The A and B agree upon some claim X_0, so the A attempts to prove X with some reasoning chain.

A says:

"X_0 implies X_1. (then some explanations)

then X_1 implies X_2 (blablabla more explanations)

then X_2 implies X_3 (blablabla more explanations)

...

finally X_(n-1) implies X."B responds to the A:

"QUOTE X_0 implies X_1. (then some explanations) /QUOTE

No, this is mistake. X_0 does not imply X_1.

QUOTE then X_1 implies X_2 (blablabla more explanations) /QUOTE

Again. You are assuming X_0 would imply X_1.

QUOTE then X_2 implies X_3 (blablabla more explanations) /QUOTE

Wrong. You are again assuming X_0 would imply X_1

...

QUOTE finally X_(n-1) implies X. /QUOTE

And again! X_0 does not imply X_1."The person A probably knows that his reasoning chain was kind of reasoning chain where each step relies on the previous one. Wouldn't it just be sufficient for B to explain why the first step was wrong once? Isn't that a deliberate attempt to make the A's post seem more inconsistent than what it really is?

 

[lisab]

There's a thread with great points reagarding argument and fallacy -

https://www.physicsforums.com/showthread.php?t=154924

 

[humanino]

The person A probably knows that his reasoning chain was kind of reasoning chain where each step relies on the previous one.

I'm not so sure. Let me try to see if I understand your point :
Assume (A=>B=>C=>...=>Z) contains one gap, say the first one : A does not imply B. It can happen that (B=>C=>...=>Z) is still true ! And most importantly, it could happen that B (and the others) are true. So quoting all the rest of the chain indicates an even worse misconception. Now assume (A=>B=>C=>...=>Z) is true, but A is false. It is a common misconception that (A=>B=>C=>...=>Z) should be false. Which is not true

Anybody who has rudimentary logic knows that. A=>B can be true with A false, a situation which does not imply that B is false.

 

[Cyrus]

I'm not so sure. Let me try to see if I understand your point :
Assume (A=>B=>C=>...=>Z) contains one gap, say the first one : A does not imply B. It can happen that (B=>C=>...=>Z) is still true ! And most importantly, it could happen that B (and the others) are true. So quoting all the rest of the chain indicates an even worse misconception. Now assume (A=>B=>C=>...=>Z) is true, but A is false. It is a common misconception that (A=>B=>C=>...=>Z) should be false. Which is not true

Anybody who has rudimentary logic knows that. A=>B can be true with A false, a situation which does not imply that B is false.

Thats not true because for large values of A, A approach B, in which case both A and B are false and your a sucker, fool. Q.E.D (Quck, and Easily Done).

Bada bing I am good.

 

[humanino]

I'm so glad that you're around Cyrus. My leg already grew quite a few inch. Would you mind pulling the other one now ?

 

[TheStatutoryApe]

I'm not so sure. Let me try to see if I understand your point :
Assume (A=>B=>C=>...=>Z) contains one gap, say the first one : A does not imply B. It can happen that (B=>C=>...=>Z) is still true ! And most importantly, it could happen that B (and the others) are true. So quoting all the rest of the chain indicates an even worse misconception. Now assume (A=>B=>C=>...=>Z) is true, but A is false. It is a common misconception that (A=>B=>C=>...=>Z) should be false. Which is not true

Anybody who has rudimentary logic knows that. A=>B can be true with A false, a situation which does not imply that B is false.

I could be wrong but I think Jostpuur's example is supposing that the logic string is based on a foundation, perhaps faulty, established in the first link. If the foundation is faulty the logic string collapses, though it is certainly possible one could change the foundation and have the rest follow logically.
And I think he means to focus on the argument skills of the person refuting. Perhaps they ought suggest a change in the foundation of the logic string that would make sense to them instead of simply, and repeatedly, refuting the foundation.

 

[humanino]

I'll give a silly example then. George is a monkey. Monkey eat only bananas. People eating only bananas develop deadly nutrient deficiencies. The perspective of a president dying from nutrient deficiencies is worth impeachment. Therefore, democrats should act now.

Now assume that only the first one is false (which is obviously not the case, but I'm just making an example. The third point for instance requires that monkeys can also be people.). Assume in addition that George does eat only bananas, independently of the fact that he is not a money. Democrats should still act now.

Please don't be insulted by my silly example. I just expect that Dick would argue "but George is not a monkey, so democrats should not do anything !" ignoring (willingly or not) the fact that yes, George does only eat bananas, because he only is too happy to have found a gap in the argument.

The reason I took such a silly example is that my point is purely logical. I do not claim that Jostpuur's point was purely logical : "a deliberate attempt" seems to indicate that indeed, the person does understand the logic, and is constructing a rhetorical, manipulating, argument.

 

[Cyrus]

I'm so glad that you're around Cyrus. My leg already grew quite a few inch. Would you mind pulling the other one now ?

Im not touching you with a 10 foot pole.

 

[DaveC426913]

The person A probably knows that his reasoning chain was kind of reasoning chain where each step relies on the previous one. Wouldn't it just be sufficient for B to explain why the first step was wrong once? Isn't that a deliberate attempt to make the A's post seem more inconsistent than what it really is?

In an ideal world, yes (it would be this way in a formally moderated debate). But discussions, especially forum threads, have a way of being quite fluid.

(In fact, that's a good analogy.) If you have a chance to divert a stream while it's still a trickle (i.e. only X_1 has been posited), it only needs a small rock. If you don't have a chance to divert it until well downstream (A has managed to write his great big long thread and post the whole thing), then your one rock, even of it's quite large, will not divert the stream, the water will just flow right around and over it. You're now faced with the task of damming the whole river, including every tributary that has joined up with the stream. diverting the original spring accomplishes virtually nothing.

Additionally, having more than two people in a discussion causes further complications - the river now becomes a delta, forking off in multiple directions. Good luck stopping that.

 

[rewebster]

I'm so glad that you're around Cyrus. My leg already grew quite a few inch. Would you mind pulling the other one now ?

does 'other one' imply/assume the other 'leg', or could it imply/refer to 'pulling the other finger'?

 

[jostpuur]

In an ideal world, yes (it would be this way in a formally moderated debate). But discussions, especially forum threads, have a way of being quite fluid.

(In fact, that's a good analogy.) If you have a chance to divert a stream while it's still a trickle (i.e. only X_1 has been posited), it only needs a small rock. If you don't have a chance to divert it until well downstream (A has managed to write his great big long thread and post the whole thing), then your one rock, even of it's quite large, will not divert the stream, the water will just flow right around and over it. You're now faced with the task of damming the whole river, including every tributary that has joined up with the stream. diverting the original spring accomplishes virtually nothing.

Additionally, having more than two people in a discussion causes further complications - the river now becomes a delta, forking off in multiple directions. Good luck stopping that.

Well this is good point. This could be done in neutral manner too. Like making civilized notes:

...
QUOTE then X_1 implies X_2 (blablabla more explanations) /QUOTE

This all relies on previous incorrect conclusion that X_0 would imply X_1.

QUOTE then X_2 implies X_3 (blablabla more explanations) /QUOTE

This all relies on previous incorrect conclusion that X_0 would imply X_1.
...

Of course it could be that A was already being aggressive, so there's not much point in blaming B. In real debate there's more going on than only the exchange of contents of the claims. I didn't give enough initial data in the opening post, to fully decide what's appropriate from B

Another point of view is that it could be that A was actually right, and B wrong. In this case B's style to spread his disagreement over the entire post is a technique to make it more difficult to see the true source of disagreement, and to direct the debate to other unclearer topics.

 

[jostpuur]

I am aware of the fact that the implication X_n -> X_(n+1) can be correct even though the claim X_n or the implication X_(n-1) -> X_n would be incorrect. It wasn't really my point to get into details of logic in this thing, though...

 

[rootX]

nerds ...

 

[DaveC426913]

nerds ...

While an XKCD fan myself (as many of us are) I'm trying to figure out what this has to do with the topic.

 

[rootX]

While an XKCD fan myself (as many of us are) I'm trying to figure out what this has to do with the topic.

According to that xkcd, both person A and B are nerds who would go far beyond to prove their points.

Definitely not a strong connection, and I agree with you about that. But, when I looked at person a and b making arguments, it reminded me of that xckd.