Logical Fallacies and the Art of Debate | Hacker News Reader

Logical Fallacies and the Art of Debate

csun.edu

67 pointsffpaladin32 comments

I was a philosophy major and figured out accidentally in an academic setting that logic was one of my strong suits. After considering law, I decided I didn't want to live my day-to-life dealing with using tactics of logic and the legal system to battle against others. Of all the classes I ever took however, the most useful class for me personally was logic as it did the most to prepare me for doing business deals. Most business deals finally come down to negotiating and its good to make sure you can justify your value and easily knock down anyone who tries to undermine your value, on the spot, especially for fallacious reasons. And the more you have command of logic, the more your other qualities which are helpful for doing business deals may shine. This seems to be the case especially for those who like to design their own deals instead of take a defensive role to the another party's designs. And then comes the discussions of more in-depth terms, and logic becomes more and more useful all the way through the end of a contract. And ultimately, lawyers, who you may depend on for this part of your deal, are not usually meant to act as advisors to your business and tell you what you want to do, they are usually there just to protect you.

As others have pointed out, calling a logical fallacy card to ding an opponent may indeed often miss the point if the objective is to simply win, though I have found in doing business deals, it is logic that is most useful to protect my value and ideas, as opposed to just winning them.

So I would suggest that this is an article worth close study and that leaning about fallacies is a great way to get right at the elements involved in sound logic.

*note: this comment was not meant to be an argument, just a "subjective" comment for consideration.

Really? I've found that being good at logic (and good reasoning in general) makes me a lot worse at convincing others, because my motivations for believing things depart so much from theirs.

I guess it depends on what industry you are dealing with and on what level. When you are dealing with Hollywood, they tend to pull out ALL the tricks. Protection and savviness on business deals is a must. Its an aggressive world out there and if you are going to take your business out of doing family and friends business, you may need to be prepared for sharks. We have done contracts within many very competitive markets and it can get aggressive out there.

You deal with sharks by beating them at negotiation and people skills, not by beating them at logic. Logic is a defensive weapon only--it keeps you from getting fooled, but it won't really sway others.

Good point about "it keeps you from getting fooled". Thats a serious conclusion you make, and however you needed to get there, Im glad you were able to finally arrive at my main point. :)

In law, when logic does not favor your client's position, you are trained to attack in illogical ways that still might win, e.g., appeal to prejudice, attack the person, distort the issues through (subtle) misrepresentations (crude ones being too easily exposed). It can be wearying to listen to this sort of thing being endlessly paraded before any advocate's forum to the detriment of both truth and logic.

This piece gathers and reasonably explains a useful grouping of logical fallacies. Among them: (1) Begging the question ("petitio principii"): "This is the fallacy of assuming, when trying to prove something, what it is that you are trying prove" (for more, see http://en.wikipedia.org/wiki/Begging_the_question); (2) Tu quoque ("So's your old man"): "This is the fallacy of defending an error in one's reasoning by pointing out that one's opponent has made the same error."

It seems that that would be a natural outgrowth of the adversarial system. If your goal is to persuade people and not to find the truth, then it is rational to use any ethical technique available to do so. A more inquisitorial system would largely be able to avoid this issue, but of course it creates issues of its own.

Pet peeve: the confusion of understanding between "logical fallacy" when used in terms of a debate and "logical fallacy" when used in the sens of a mathematical or geometric proof.

Conversations about topics inside a system with a fixed set of consistent rules, like math, consist of not making fallacies. He who makes no fallacies can extend the system in unforeseen ways. This is the search for truth.

Human language and the totality of knowledge is not a formal system with complete rules and non-contradictions, therefore not only will an elimination of fallacies not lead anywhere, it's probably impossible to structure any kind of discussion without introducing one. So if you use a list of fallacies as a way to somehow "ding" an opponent, as if he would only use a fallacy if he were somehow making a mistake, you've missed the point. The author of the article is more correct to say that you're either debating or discussing. If you're debating, you're using all sorts of rhetorical tricks. If you're discussing, you're still using them, but the purpose isn't to score points, it's to find some agreeable progress in mutual understanding.

A lot to chew on here. First, I think your distinction between mathmatical proofs and everything else (?) is a bit simplistic. Second, you seem to suggest that the non-math side of the divide ("human language") is necessarily not truth seeking and that any attempt to point out a fallacy in such a context is pointless. That strikes me as far too strong.

Imagine I am discussing a topic with someone. The topic might be anything, but let's stipulate that it's not a member of the mathematical proof family that you mention.

If I or the other person commits a logical fallacy and someone points that out, we can avoid one bad outcome: trusting an invalid conclusion. (I'm using 'valid' and 'invalid' in the sense philosophers use it of an argument where the conclusion doesn't logically follow from the premises. An invalid argument may have a true conclusion, but the form of the argument makes it unreliable. Example: My name is Peter. Therefore, I will die. The conclusion is true, but the premise doesn't actually get me there.)

I completely agree that conversation shouldn't be like a scored debate, and so I think pointing out fallacies to ding other people is childish and largely pointless. But if you are actually striving to understand something, then an awareness of (common) fallacies can be very, very useful.

right on. Many disasters can be easily avoided if we challenge the faulty logic involved.

I'd like to see more real debates amongst our decision makers. Everything today is designed to avoid them. We would certainly get better decisions and the mental demands alone will make for sharper leaders.

In the real world, unfortunately, if you need to challenge the faulty logic of your opponent, you already lost the argument.

so you've lost the instant someone someone presents a faulty argument? does that mean you win now?

> Second, you seem to suggest that the non-math side of the divide ("human language") is necessarily not truth seeking and that any attempt to point out a fallacy in such a context is pointless.

That's a straw man. He said: "it's probably impossible to structure any kind of discussion without introducing [a fallacy]". Because you can't avoid fallacies doesn't mean that pointing to (some of) them is pointless.

I think you agree with Daniel more than you realize.

> That's a straw man. He said: "it's probably impossible to structure any kind of discussion without introducing [a fallacy]". Because you can't avoid fallacies doesn't mean that pointing to (some of) them is pointless.

Here's his full sentence: Human language and the totality of knowledge is not a formal system with complete rules and non-contradictions, therefore not only will an elimination of fallacies not lead anywhere, it's probably impossible to structure any kind of discussion without introducing one.

The key bit to me is "therefore not only will an elimination of fallacies not lead anywhere." You may be right about his larger meaning, but I take that part of the sentence to mean that there is no point in eliminating fallacies ("not lead anywhere").

I understood "elimination of fallacies" as "elimination of all fallacies". That wouldn't mean we shouldn't avoid (or point to) the worst ones.

I'm insisting because I can't believe that someone actually think that no fallacy is worth eliminating. Unless he state it without ambiguity. Daniel didn't. Plus, he stated the difference between debate and conversation. I think we can equate "mutual understanding" with "search for the truth" here.

So Daniel, would you tell us what you actually think? Are some fallacies worth eliminating? Can the human language be truth seeking?

> I'm insisting because I can't believe that someone actually think that no fallacy is worth eliminating. Unless he state it without ambiguity.

Principle of charity? http://en.wikipedia.org/wiki/Principle_of_charity

I took "mutual understanding" to be an alternative to "search for the truth" - and a very carefully chosen one at that. Although I don't agree, I can see a number of potential arguments for the idea (given some of his other premises) that in math we find the search for truth, whereas in human conversations we find increased mutual understanding (under the best conditions), but no hope of a search for truth.

I'm insisting myself because the debate is on a topic I care about and one that's inherently interesting.

Principle of humanity, more likely.

"Find the search for truth"? Either you search for truth or you don't. In the process, you may (or may not) find the truth, and you may (or may not) be closer to it. What did you actually mean by "hope of a search for truth"?

Now, trying to "find some agreeable progress in mutual understanding" sounds like a damn good substitute to "searching for truth". Mutual understanding is the best approximation of truth I know of, when truth actually has something to do with the conversation.

Now that I think of it, mutual understanding may not be such a good substitute, but merely a prerequisite. Meaning, until the different parties understand where they agree, and where they disagree (and maybe even why they do), search for the truth is hopeless.

> "Find the search for truth"? Either you search for truth or you don't. In the process, you may (or may not) find the truth, and you may (or may not) be closer to it. What did you actually mean by "hope of a search for truth"?

I meant that (per the argument under discussion), in some areas there is no (real) possibility of searching for the truth. So, in those areas you don't "find the search for truth." When the OP talks about math vs. human language (all other contexts?), he appears to imply that in math it is possible to search for truth, but in "human language", there is no possibility of finding truth. So, what I meant was roughly this (the following is a reconstruction of the OP's argument, as I understand it, not my views):

1. In math, where there is "a fixed set of consistent rules" (his words), you can meaningfully search for truth.

2. In "human language", which "is not a formal system with complete rules and non-contradictions" (his words), you cannot meaningfully search for truth.

3. The phrase "mutual understanding" indicates a second-best option (since the search for truth is ruled out) for "human language". As you and I talk - now for instance - we cannot usefully search for truth, but we can at least try to figure out what the other person intends to say. That's "mutual understanding," and I think you can see why it's only a consolation prize compared with the search for truth.

The whole thing reminds me a bit of a certain kind of logical positivism. Only some statements are even potentially truth-evaluable. (For example 'x = x' is truth evaluable.) All the rest is simply an expression of personal belief, attitude, disposition or emotion. Under that view, if I say "action x is always wrong" and someone else says "under some circumstances action x is not wrong", the best we can do is figure out what the other person means by their statement. But there is no possibility of saying whether either of those statements is true or false, since such statements are (by definition) not truth-evaluable. That's the kind of thing I thought the OP was saying.

I've never heard of a school whose abbreviation is csun; thus, this list probably has a bunch of errors. Not worth the read.

Your argument is logically fallacious, therefore this list has no errors.

Doubly so because it made it to the front page of Hacker News.

My thinking is that the author has a vested interest in not teaching his opponents the tricks of debating therefore the list is incorrect and incomplete.

The author wrote two other articles about what debaters should know about respectively Law and Economics, which will provide you some basic models to help you in your argumentation and your critical thinking about these subjects as a layman. They are on linked on his homepage http://www.csun.edu/~dgw61315/dgwdebate.html

Could somebody suggest similar articles about other topics? For example statistics.

I use this a lot in debate: http://en.wikipedia.org/wiki/Reductio_ad_absurdum

(Not itself a fallacy)

This article actually does a good job of explaining both sides of these 'logical fallacies' including why they aren't always invalid. It's the best job I've seen so far of refuting the 'Fallacy Fallacy'. In particular it points out how the 'burden of proof' plays a big part in determining the validity of some arguments.

Interestingly, the entire setup of the article---how to use an accusation of "logical fallacy" ("preferably both in Latin and English") to impress a debate judge to dismiss an opponent's argument...

...is itself an argumentum ad verecundiam, an argument to authority!

Which is not to say that it's not a good debate technique. :)

He who first resorts to pointing out logical fallacies has lost the debate.

I'm not sure if you're kidding, but if not, that's an interesting rule of thumb. I can half see your point: when arguing with normal people, if you need to resort to pointing out their fallacies, it's probably not worth it. On the other hand, if you're arguing with a Philosophy major, then pointing out a fallacy doesn't necessarily signal failure. It's closer to starting round two.

The idea isn't to point them out, but to expose them without directly pointing them out.

The article's author has a different idea:

Besides, let's be honest: debate is not just about finding truth, it's also about winning. If you think a fallacious argument can slide by and persuade the judge to vote for you, you're going to make it, right? The trick is not getting caught.

The article is talking about a college debate, which has judges and rules, not a regular debate between people. The article also talks about how to point out the logical fallacy in a way that gets you the most points for it (which in some cases involves pointing it out directly, Latin and all, and in some cases doesn't).

Actually, I'd say not. So long as He has not fallen for any himself it's sure footing to remove counter arguments through their logical failings.

In fact I'd say it is a sure sign of winning a debate :)

Have you noticed that the author is a Libertarian? (From examples of logical fallacies he quotes).

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