Thou Shalt Not Commit Logical Fallacies [poster]

http://www.yourlogicalfallacyis.com/poster

by jonah • 14 years ago

81 42 14 years ago

rollypolly• 14 years ago

HN could use a cheat-sheet version of this above the comment box. ;)

jarin• 14 years ago

If anyone wants it without having to go to the print shop, it's up on Zazzle: http://www.zazzle.com/thou_shalt_not_commit_logical_fallacie...

You can also add it to Zazzle yourself and get it for a little cheaper, just make sure you put in the right dimensions, i.e. A2 (594x420mm or 23.4 x 16.5 inches) or A1 (841x594mm or 33.1 x 23.4 inches)

eeeeaaii2• 14 years ago

I have to say this.

I was getting annoyed at the oversimplified, vague, and/or unclear explanations on the poster. It's great to have a poster cataloging logical fallacies, but it's not so great if it doesn't actually explain them very well.

So I go to the home page of the site, where the first sentence reads:

"A logical fallacy is usually what has happened when someone is wrong about something."

FACEPALM.

The validity of a logical argument has NOTHING to do with the actual veracity (rightness or wrongness) of the propositions. This is basic stuff. Logic is the process of figure out what other things we know based on what we already know. If what we think we know is wrong, then we can make all the logically correct arguments we want and we'll still be drawing wrong conclusions.

bunderbunder2• 14 years ago

And, on the other side of the coin, I fear it encourages folks to fall victim to the 'fallacy fallacy': Thinking that the presence of a logical fallacy in an argument implies that its thesis is incorrect.

On a completely different coin, nobody ever won an argument by treating it as a game of Spot the Logical Fallacy. All you'll win playing that game is a reputation for being insufferable.

repsilat2• 14 years ago

> the 'fallacy fallacy': Thinking that the presence of a logical fallacy in an argument implies that its thesis is incorrect.

It's worse than that. Paying too much attention to rigour and the mathematical validity of arguments unduly privileges strict logical argumentation over "traditional" informal argumentation.

Outside of technical areas there are almost no arguments amenable to pure logical argumentation. Think about it - why would you be arguing over something that can be mechanically deduced with certainty? In most circumstances logical syllogisms and the like are used only as "glue" to hold the real argument together.

We should recognise that arguments using these "fallacies" don't have absolute persuasive power, but we shouldn't go so far as to say that they can have no persuasive power at all.

jiggy20115• 14 years ago

That is true, but I think it is good to educate people to spot common mistakes that are made during arguments.

For example I often see people winning casual arguments by overusing emotive language , belittling the opinion of their opponent or by misrepresenting (or misunderstanding) what they are saying.

JesseR2• 14 years ago

Hello, I created this site. The qualifier of 'usually' means that there's not actually a fallacy being committed, rather a very generic statement about how fallacious reasoning is usually at play when people are wrong (which is certainly true).

You're right that the logical coherence of an argument doesn't have any intrinsic bearing upon the proposition that it supports being either true or false, but this does not invalidate the point that when people are wrong, they're more often than not guilty of committing fallacies in both their reasoning and their defence of their point.

Also, the idea of the site is to be very simple rather than comprehensive. Preaching to the choir is all good and well, but I'm more interested in spreading knowledge to children and people who haven't been exposed to or understood these concepts previously (however many uber nerds have emailed me saying that they've enjoyed it and hung the poster up).

From the FAQ section: The point of the site is to make common logical fallacies easily understood, so listing every single one isn't really what it's about. If you want to learn more about logical fallacies check out this comprehensive interactive list of all the formal and informal fallacies.

Domenic_S2• 14 years ago

> when people are wrong, they're more often than not guilty of committing fallacies in both their reasoning and their defence of their point.

Hasty generalization :)

I have found that when people are wrong, it's usually because they are incorrect about the facts that they're basing their argument on.

eeeeaaii2• 14 years ago

Sorry to harsh on the site, I realize it's your creation that you've put time and effort into, and I'm just some random guy killing time on the internet.

That said, I will say that the poster explanations were frustrating for me. I've studied formal logic via computer science, but not enough argumentation or philosophical logic -- so some of these fallacies were new to me. For example "no true scotsman" -- but the explanation did nothing to help me understand it. I'm type of person who learns by example, but your examples are so cutesy and weird that I can't actually relate them back to anything useful. Something about sugar in porridge? What I want is to be able to recognize these when I see them, but I'm just not getting it from your explanation. Real-world examples would be MUCH better.

Part of why I'm frustrated is I've been wishing for a resource like this for a long time -- someone who really understands argumentation, clearly and simply explaining logical fallacies, with real-world examples. I've read about "straw man" repeatedly, over and over -- definition after definition -- and I still am not confident that I could identify it if I saw it. Very frustrating. Feels like a lost opportunity. Maybe it's working for others, not me though. sorry

Domenic_S2• 14 years ago

Agree. It's like 40,000 freshmen took Intro to Logic classes lately on the internet. If I hear one more person throw out No True Scotsman...

On a more constructive note, it seems to me that discussions of fallacies are nearly useless without first talking about deductive/inductive logic, validity & soundness, strong/weak and cogency.

rprospero• 14 years ago

The unclear explanation also disturbing considering that the abuse of logical fallacies has almost become an internet meme. The No True Scotsman fallacy seems particularly popular in this regard.

I've noticed a common trend in arguments of the following sort:

A: No Communist dictatorship has ever had long term economic prosperity. B: What about the United States? It's had incredible economic growth for over a hundred years. A: The United Sates isn't an communist dictatorship. B: That's the No True Scotsman fallacy.

jiggy20115• 14 years ago

I think it's impossible to have a rational argument with many Americans if you use the word "communism" anywhere.

mccoyst• 14 years ago

"The validity of a logical argument has NOTHING to do with the actual veracity (rightness or wrongness) of the propositions."

This is on the poster.

jeremysalwen2• 14 years ago

It's incredibly ironic that this poster features Plato, Socrates, and Aristotle. They all commit ALL of these fallacies with regularity, with the exception perhaps of the Texas Sharpshooter, because in order to commit that one, you actually have to appeal to data.

“Aristotle maintained that women have fewer teeth than men; although he was twice married, it never occurred to him to verify this statement by examining his wives' mouths.” ― Bertrand Russell, The Impact of Science on Society

morsch• 14 years ago

How is that a logical fallacy? That's just a lack of data and an unwillingness to gather it.

jeremysalwen2• 14 years ago

Oh, certainly, that wasn't the point of the quote. I was just pointing out how supremely stupid these guys were, for everything they gave us. But it probably falls lightly under burden of proof.

There's a quote which I thought was from a friend of mine, but when I asked him, he denies ever saying it, so I'm not sure where it's from: "Philosophy is the history of bad arguments." I just quoted Russel, because he's a bit more of a respected authority on the subject.

dustyreagan• 14 years ago

Great poster, but instead of donation button, you should have a "buy a print" button.

ekianjo• 14 years ago

It's not perfect but the icons are pretty well done. I imagine they could be used to "flag" posts, to let people know when they commit fallacies.

JoeAltmaier• 14 years ago

Great salesmanship tool worksheet!

alttag• 14 years ago

... would be nice if I could read the poster. "Account has been suspended" error message.

Sometime after I loaded the landing page but before I could click a link, the account/site went "poof".

jonah3• 14 years ago

Back up, but if it goes down again here's a cached copy: http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_...

SneakyBeak• 14 years ago

Site is down.

jonah3• 14 years ago

Copy here: http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_...

Locke16894• 14 years ago

A lot of these are wrong. Examples:

Slippery slope -- Asserting that if we allow A to happen, then Z will consequently happen too, therefore A should not happen.

Slippery slope is not necessarily a fallacy -- it is only a fallacy if the warrant is extreme. If we were arguing about dropping lit cigarette butts into the trash and we both agreed that fires were bad and I made the claim that we shouldn't drop cigarettes in the trash because they often cause fires (and cited data to that effect) there would be no fallacy in my argument.

Appeal to authority -- Using the opinion or position of an authority figure, or institution of authority, in place of an actual argument.

This one actually infuriates me because it may be the most wrongly used logical fallacy. First, because most people who use this argument are not making a logical deduction, they're making a statistical argument. To cite from Wikipedia:

The appeal to authority may take several forms. As a statistical syllogism, it will have the following basic structure:[1] Most of what authority a has to say on subject matter S is correct. a says p about S. Therefore, p is correct. The strength of this argument depends upon two factors:[1][2] The authority is a legitimate expert on the subject. A consensus exists among legitimate experts on the matter under discussion.

There is nothing wrong with this argument. The example given in the poster is very bad. As a PL student I have a bit of experience with formal methods and I'll remind everyone that the only things which can be proven using logic are those which follow directly from the definitions. In real arguments, these structures basically never exist. The truth never follows necessarily from the things people say, it's almost always a statistical argument. The fact that medical authorities used to think wrong things about the body didn't necessarily mean that it is or was wrong to believe in the body of scientific knowledge at the time. It only means that you have to be aware of the error margin in your statistics.

olalonde2• 14 years ago

Have you read the longer descriptions?

http://www.yourlogicalfallacyis.com/appeal-to-authority

http://www.yourlogicalfallacyis.com/slippery-slope

Your concerns seem to be addressed there.

Locke16894• 14 years ago

First, those links address my points improperly, if at all. Slippery slope once again assumes that the warrant is extreme but there is no such guarantee in the construction presented.

Second, even if the extra links on the site were correct I don't see why that would make the poster itself any less wrong.

Gormo• 14 years ago

> Slippery slope is not necessarily a fallacy -- it is only a fallacy if the warrant is extreme

It's only a fallacy to suggest that a slippery slope is logically entailed, i.e. to assert without further argument that it's logically necessary for Z to happen if A happens simply because Z is a more extreme form of A.

But slippery slopes certainly do exist empirically, especially with respect to politics, and given the actual nature of a particular political milieu, it can be entirely reasonable to suggest that implementing one policy makes it more likely for a more extreme version of that policy to come about in the future.

> Appeal to authority -- Using the opinion or position of an authority figure, or institution of authority, in place of an actual argument.

Same thing here. As you've said, it's entirely reasonable to apply a heuristic that gives greater credibility to a source whose statements have previously proven useful or valid than one that hasn't.

The fallacy of the appeal to authority is in assuming that a given statement is true because an 'expert' has made it, but it's entirely reasonable to expect that a person you regard as an expert is more likely to make statements that are valid in their own right.

The primary fallacy of those who excessively discuss logical fallacies is the assumption that most arguments actually are applications of deterministic logic intended to assert an unambiguously correct answer to an unambiguous question in the first place. Most arguments really involve the application of heuristics in complex and stochastic contexts, in order to establish an understanding that's marginally more useful than the status quo. Many arguments also involve attempts to reconcile competing conceptions of the desired end state, and are not simply disputes regarding the reasoning applied to obtain a presumptively agreed-upon end state. Formal deductive logic isn't the most relevant template in either of these scenarios.

jiggy20115• 14 years ago

The only thing more annoying than people who regularly commit logical fallacies are teenagers who argue on the Internet having just read the wikipedia page on logical fallacies.

For example: "the british medical association has said that smoking increases risk of cancer" therefor it is best not to smoke.

At which point you will get "Aha! You just committed appeal to authority and a slippery slope fallacy, you must be wrong!".

I suppose this is partly because in real life arguments we very rarely have sufficient knowledge in any subject to make concrete formal arguments based on direct observations, we are usually discussing the likelyhood of different things being true.

instakill• 14 years ago

Reddit has come to love the reference to the straw man fallacy of late.

Cogito• 14 years ago

Though Shall Not Propagate Common Myths: from 'bandwagon' - "The ﬂaw in this argument is that the popularity of an idea has absolutely no bearing on its validity. If it did, then the Earth would have made itself ﬂat for most of history to accommodate people’s popular belief."

While 'most of history' is a long time, the knowledge of a round earth has been around (and popular) since around 300 BC. It may be true that humans, and even that written (let alone verbal) histories, have been around for much more than 2000 years, the commonness of this myth warrants a different example. You wouldn't want to be seen supporting a position that only exists because many people think it is true, now would you :D

pepve• 14 years ago

Hmm, I'm guilty of most of these.

So now I think they are heuristics rather than absolute measurements. And we should use them to teach ourselves something about logic, but not others.

Thou Shalt Not Commit Logical Fallacies [poster]

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