Fallacies

What about looking at these lists of fallacies as vocabulary building tools? Perhaps fallacies are all variations on a handful of errors, but it certainly expedites conversation to be able to say, "No, that's just begging the question." Otherwise I would have to waste my breath disagreeing in a more clumsy way.

Your last sentence feels unfinished.

At the end of the day, reasoning is an art, and an art worth your learning. The question is rather, whether you be capable of learning it? [0]

[0] http://www.gutenberg.org/cache/epub/683/pg683.html

> But I think this sort of enumeration of logical fallacies is of very limited value. In the abstract there are only a few ways that arguments fail, and informal fallacies are all iterations on an extremely similar theme.

I think the value of enumerations -- in addition to creating a vocabulary which is often useful in discussing problems with an argument, even if, as you correctly note, exactly which fallacy is most applicable is a subject of interpretation -- is that it helps recognize instances of potentially problematic arguments. Even if, on a certain level of abstraction, a lot of the named fallacies are just different views of a smaller number of real problems, understanding the different manifestations of those common problems helps to recognize them in practice.

I think I get what you're saying, but I also think it more usefully applies to the conversations you might have with your philosophy friends. Meanwhile, there seem to be a lot of people on my Facebook wall who could benefit from a list of basic fallacies.

Fwiw, in my experience, simply knowing all or as many as possible logical fallacies better enables one to recognize and discard invalid arguments quicker. It facilitates a more systematic process of elimination.

It also helps one realize and appreciate just how difficult it is to construct a correct argument, when you can quickly spot the fallacies in your own assertions. As a result, on a personal level, this has caused me to tend to read, listen, and question more, and assert less.

Just so. (My late dad was an industrial engineer whose recreational reading was all about the philosophy of science, so I grew up in a home with logic textbooks on the home bookshelf.) Plenty of incorrect arguments encountered here on Hacker News or elsewhere in cyberspace are incorrect not so much because they fit on a checklist of classical logical fallacies, but rather because they are based on false factual premises. One has to keep seeking knowledge of the world to recognize mistaken premises of arguments. One thing I enjoy about Hacker News is that it includes people from all over the world, including people who have seen places I have never seen, and done things I have never done, so that I can learn new facts here as I read discussion threads. That is often every bit as valuable as knowing lists of logical fallacies, although I did do a bit of teaching of formal deductive logic back in the days when I was a high school debate coach.

A previous comment of mine

https://news.ycombinator.com/item?id=5835453

from a thread recommended in another comment on this thread goes into more detail about why logical fallacies are not the only problems to look for when evaluating claims for truth or falsehood.

> The best thing is to learn about different sorts of reasoning and how they work in good cases, and pick up a feel for some fallacies along the way. At the end of the day, reasoning is an art.

Do you have good suggestions for learning about different sorts of reasoning?

Actually it's "no true Scotsman".

Man, now I just don't know about everything else you've written there.

(kidding)

Understanding that "life can't be reduced to some axiomatic system" is a really important part of being a well-rounded human.

But I quibble on calling it a logical fallacy. It is emphatically not a logical fallacy. That's the whole point you're trying to make - which is that logic itself is limited in its ability to capture the totality of human experience.

Other philosophers call this the limits of Reason (capital R) or the failure of the Enlightenment. But calling it 'Logical Fallacy #1' undermines the very lesson you are trying to impart.

I am curious have you ever taken any philosophy classes?

> Well, it depends on how you define correct or better. If you value tradition and see conformance to it as the most important metric, then X is indeed better for you.

This is a common response when people first hear/read about "appeals to tradition." So common that that linked web page deals with this response:

Obviously, age does have a bearing in some contexts. For example, if a person concluded that aged wine would be better than brand new wine, he would not be committing an Appeal to Tradition. This is because, in such cases the age of the thing is relevant to its quality. Thus, the fallacy is committed only when the age is not, in and of itself, relevant to the claim.

Just for completeness, the following is from rationalwiki has the following to say about your beloved "scotchman":

"Broadly speaking, the fallacy does not apply if there is a clear and well understood definition of what membership in a group requires and it is that definition which is broken (e.g., "no honest man would lie like that!", "no Christian would worship Satan!" and so on). "[1]

[1] http://rationalwiki.org/wiki/No_True_Scotsman

Thanks coldtea, I think you're onto something important. I'll try to expand on it, tho it's hard to do this briefly.

People reason (and discuss) in several modes, which are ordinarily mixed freely. Deductive, a.k.a. logical (in the proper sense) reasoning is one, and the fallacy-or-not analysis is strictly applicable.

Another mode is that of empirical science, which is basically inductive. You can't prove logically that, for example, substance X causes condition C, but you can establish a good probability by isolating the case, ruling out other factors, showing that the relation is reliably reproducible, etc..

A third mode is humanistic or intuitive. It is an error to suppose that this is unreliable or categorically invalid. Say you have thefts at a workplace, and question employees, and most answer straightforwardly, but one is evasive, furtive, avoids eye contact, can't explain simple events - despite the inapplicability of the logical or scientific modes, this is a rational basis for directing suspicion.

Errors of a meta variety enter when one mode is evaluated by the standards for another. E.g., this writer depicts "slippery slope" as a fallacy of logic by inserting "inevitably" in his interpretation of claims - attributing to the argument-maker the claim that A inevitably leads to B. But in fact "slippery slope" belongs to the third mode, and as such it can be valid - censors do tend to expand their categories, and the actual claim may be, not that the progression is inevitable, but instead that it's unacceptable to go further in that direction - and on this kind of interpretataion there may be no fallacy at all.

It's a good list of logic fallacies, but we just have ot make sure we don't try to apply the refutations in the context of other modes of reasoning.

"Who is to say what metric you should use for "correct", in issues like ethical ones, that are not clear cut and measurable as things are in the hard sciences and mathematics?"

See this talk[1] by Sam Harris for an argument as to why that is an illusion. In essence he argues that we make axiomatic claims all the time in areas for which there aren't specifically quantifiable goals. In terms of morality the metric is the well-being of conscious creatures. If you argue that there's something else that's more important than the well being of conscious creatures then you probably don't know what you mean.

Likewise with the idea of 'health'. 'Health' is a squishy idea. But if you were to argue that "My idea of health is involuntarily vomiting 6 times a day" we'd have nothing to discuss.

[1]http://www.ted.com/talks/sam_harris_science_can_show_what_s_...

You may find this article titled "Your baloney detection kit sucks" interesting:

http://plover.net/~bonds/bdksucks.html

Which was discussed on HN under the title "Logical Fallacies Are Usually Irrelevant or Cited Incorrectly":

https://news.ycombinator.com/item?id=5832320

The way I look at it is that arguments are either factual or normative. Facts can be easy to test even if they are counter-intuitive. Normative, since you can't derive "is" from "ought" alone, means you are ultimately resting the conclusion on moral or value-based axioms. While people can reasonably disagree on the value axioms themselves, there might still be logical errors in the implications that flow from it, so it can still be useful to engage in a dialect to test for that.

You're completely misrepresenting what the No True Scotsman fallacy is. The key characteristic of a No True Scotsman fallacy is that the arguers original claim is revised to handle a counterexample. In the titular example, the arguer originally says "no Scotsman does x," and the obvious implied definition of "Scotsman" is simply a man from Scotland. But when faced with a counterexample (a man from Scotland who does do x), the arguer revises the original claim by adding the word "true." Under this revelation, the arguer's original claim is not an actual claim about what men from Scotland do, but rather a proposed definition for the term "true Scotsman."

> "In real life groups CAN be argued to have certain characteristics to recognize members from non-members, hypocritical members, non-practicing members, posers and "fakes". So the "no true scotchman" fallacy breaks down when you're dealing with such nuances."

On the other hand, where this most frequently pops up^, there is frequently no authoritative definition of what constitutes membership. Where there is, there is frequently no authoritative interpretation of the definition.

^ Any internet argument involving religion. The best you can typically manage is membership of particular sects which happen to have an agreed upon defining body. If the Pope says that you are not a Roman Catholic, you are pretty much by definition not a Roman Catholic. However if I define "Christian" in clear unambiguous terms, then point to my definition when asserting that somebody who claims to be a Christians is not a true Christian, then really I have said little of interest. That person may very well be a Christian by a definition other than my own (for instance, according to their definition), and I have justification for asserting that my definition is the true definition and theirs is false.

The issue here is not quite that there is a true Scotsman fallacy going on. Rather it is a failure to agree to the definition of terms before engaging in the discussion.

They aren't intended as some magical argument ending tool, they are designed as reminders are common flaws in logic. They are more for personal use than use against others, because it is easy to fall into bad logic, even more so when emotions (notoriously immune to logic) are involved. Being aware of them will help you be self-aware.

RE: "No True Scotsman" -- you missed the point a bit. The point is that it is a shell game. "No hackers news reader would EVER do X" ... I link to a hackers news reader doing EXACTLY X ... "Well, no REAL hackers news reader" -- it is a informal fallacy about goal moving basically. You can't add "no REAL abc" to excuse counterpoints, because it means that ANYTHING I say / prove / point out, you will always claim "no TRUE hacker news reader would do that", making the argument pointless.

Re: Appeal to tradition. The point is that tradition has no inherent value, and doesn't relate to correctness. If my mother thought 2+2=17... and she taught that to me, and I taught that to my children, that would be a tradition in our family. The point is that just cause something is traditional doesn't mean it is correct.

Attacks against credentials are valid against an argument to authority (in which case they are, in fact, pointing out a fallacy), but you only have an argument to authority when a conclusion is offered on the sole basis that the conclusion was offered by an authority. When the actual argument by the alleged authority is presented (including by reference), an attack against credentials is not a valid rebuttal, because the credentials are not the support offered for the conclusion. It is appropriate and correct to label such an attack, offered as a rebuttal, as invalid by way of the ad hominem fallacy.

> However, it is totally valid to argue that the minority of scientific studies that find, say, chemical X not to be harmful were funded by chemical companies.

I completely disagree with this common attempt to debunk the ad hominem fallacy. I truly believe that the arguer is completely separate from the argument. It's true that we shouldn't trust unsubstantiated claims from biased chemical companies. But the key is that we shouldn't trust unsubstantiated claims from unbiased sources either, even historically reliable unbiased sources.

It is highly related to the Questionable Cause fallacy: namely many believe that if two events are highly correlated then there is a causal link between them.

The business has traits X, Y, Z and successful, so we conclude that the traits X, Y, Z causes it to be successful.

This is an inductive argument I'd say, which is also listed as a fallacy on that site - see the "Examples of Fallacies" below the numbered list).

I think this person is mostly off the hook here. To begin with "I believe" makes it clear that this is an opinion, not a statement of fact. They aren't saying "bitcoin will be popular because personal computers were popular" they are saying "I can see similarities between the two".

They aren't even making any specific statement about bitcoin beyond it being controversial and interesting to nerds; both of which are already true.

"Fallacy of the undistributed middle"

all A are X

this B is X

therefore this B is A

then: for A: successful business. for X: has certain traits. for B: our new product.

The fallacy you're describing, and it's something that far too many startups do, falls under the banner of "cargo cult behaviour". It was first described by Richard Feynman, while talking about science, but the principle applies to people who merely mimic behaviour and expect the same outcome regardless of what they're doing.

"In the South Seas there is a cargo cult of people. During the war they saw airplanes land with lots of good materials, and they want the same thing to happen now. So they've arranged to imitate things like runways, to put fires along the sides of the runways, to make a wooden hut for a man to sit in, with two wooden pieces on his head like headphones and bars of bamboo sticking out like antennas--he's the controller--and they wait for the airplanes to land. They're doing everything right. The form is perfect. It looks exactly the way it looked before. But it doesn't work. No airplanes land. So I call these things cargo cult science, because they follow all the apparent precepts and forms of scientific investigation, but they're missing something essential, because the planes don't land." [1]

Believing you're building a billion dollar business because you're nationally doing the same things as someone who has built a billion dollar business before you is all too common.

[1] http://en.wikipedia.org/wiki/Cargo_cult_science

The fallacy of the form "A has trait X, A has trait Y, B has trait X, therefore B has trait Y" is an association fallacy (the particular subtype you refer to is sometimes called "honor by association", its exactly the same as the somewhat more popular "guilt by association", but where the faulty conclusion is positive rather than negative.)

http://en.wikipedia.org/wiki/Association_fallacy

A lot of this is just confusion of necessary and sufficient conditions. Assuming that X, Y, and Z are necessary, it doesn't mean they are sufficient. (Although in #1 they might not even be arguing they are necessary.)

Adding to that is the strange fascination with slippery slope on the internet. It's so bad that people will start by calling their own argument a slippery slope and implying that that makes it logically sound. Removing that from discussions would go along way to promoting reasonable debate.

Personally I would guess that biases such as confirmation bias interferes with or reasoning much more than any fallacies. Also, they are harder to get rid of.

It's important to really know what those fallacies look like, though. Just insulting someone isn't an ad hominem, and just using emotionally charged language isn't necessarily an argument that's relying on an appeal to emotion.

And if you're going to call someone out on a fallacy, don't throw it down like a trump card. SHOW how their argument is fallacious.

A lot of people also mix up ad hominem for poisoning the well.

Agreed. I also use http://www.fallacyfiles.org/taxonomy.html

Indeed, but see the date of the source: The content of these pages is a few decades old. And it is indeed quite handy in real life situations e.g. the panel discussions.

Good point. Though the fallacy fallacy is just a special case of Denying the Antecedent:

  1. If [argument is sound], then [conclusion is true].
  2. [argument] is not sound.
  3. Therefore, [conclusion] is not true.

Similar to:

  1. If it has rained, then the street is wet.
  2. It hasn't rained.
  3. Therefore, the street isn't wet.

Fallacies, fallacies, one for you, and two for me...

You are looking for this: http://en.wikipedia.org/wiki/The_Art_of_Being_Right

Yeah, I'm not crazy about the overly simplistic way some of these "fallacies" are constructed. I've always thought people who go on about fallacies in argument are incredibly smug, and the fallacies themselves are just names given to things we already recognized and understood.

In the "Appeal to Pity" fallacy the example given is:

Jill: "He'd be a terrible coach for the team." Bill: "He had his heart set on the job, and it would break if he didn't get it." Jill: "I guess he'll do an adequate job."

The argument that Bill cares immensely about the job IS evidence that he would likely do it well. A coach who cares is more likely to work hard, be more invested in the outcomes of games, etc.

But the real problem, as you mention, is that people don't argue to logically prove something. People argue to convince someone else (often not even the person they're arguing with). If you can convince people you won the argument, you won the argument. It doesn't matter whether you appealed to base human emotion or made a logically/factually empty argument.

Sounds like "appeal to authority" to me, but the way you stated it, it looks more like a straw man.

The reason to trust scientists is their method, which gives a good approximation to truth. If you are capable of evaluating their results yourself, then you don't need to trust them, but if you aren't, you have a good reason to trust them, even if technically committing the fallacy, because what else are you gonna do?

Ad hominem is when you dismiss what someone says because of who they are, not what they say.

There's no fallacy with simply not bothering to listen to them in the first place, if they have a history of spouting bullshit.

Ad Hominem is grossly 'over-diagnosed' on the internet. I would say that the vast majority of the time that somebody claims somebody else is using ad hominems, what they are actually doing is merely insulting the other person.

In other words:

  "You are wrong because of X, Y, and Z.  You fucking idiot."

not:

  "You are wrong, because you are a fucking idiot."

The first will typically get cries of "ad hominem", but it isn't. The second sentence is not being used to logically support the assertion in the first sentence, it is just a tacked on plain-old insult.

Yes, and it's amazing and ironic how many otherwise authoritative sources (i.e. sources worth reading and listening to) get this totally wrong -- they still think that the source of an idea can have a bearing on whether it is true. I think they are variously conflating three issues: (1) whether an idea is true, (2) whether one can (rationally) rely upon it in some way, (3) whether one understands it.