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Thou Shalt Not Commit Logical Fallacies [poster]

81 points by jonah 15y ago

rollypolly 15y ago
HN could use a cheat-sheet version of this above the comment box. ;)
jarin 15y 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_fallacies_poster-228887783776402214 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)
eeeeaaii 15y 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.
- bunderbunder 15y 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.
  - repsilat 15y 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.
    - jiggy2011 15y ago
      I think pointing out a fallacy can sometimes be a good defense against somebody who is insisting that something is a mechanical certainty when it is not.
      - bunderbunder 15y ago
        Yes. But more often's the case that the fearless fallacy hunter fallaciously finds fallibility by fantasizing formality or finality. Thereby committing a fallacy himself in the form of a straw man.
        jiggy2011 15y ago
        I see what you did there , I think I'm going to use that.
  - jiggy2011 15y 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.
- JesseR 15y 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_S 15y 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.
  - eeeeaaii 15y 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_S 15y 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 15y 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.
  - jiggy2011 15y ago
    I think it's impossible to have a rational argument with many Americans if you use the word "communism" anywhere.
    - repsilat 15y ago
      You have to be doubly careful with communism - McCarthyism and the "Red Scare" were clearly a little much, but the trendy counter-reaction tends to be at odds with history. The US government was infiltrated by actual communist spies (to the extent that they practically ran the State Department in the '50s), and it's hard to argue with the hundred million or so it killed in the 20th century. It's easy to say that there have been no properly realised communist societies/states, but an honest account has to hold the idea responsible for the ubiquitous oppression and murder committed by regimes attempting to create them. I won't argue that the Americans you talked to can give a reasoned condemnation of communism, but with its historical baggage the burden tends to swing the other way. It's hard to have a rational argument with a lot of people about Nazism, but it's hard to criticise people for trusting that it's not for them.
- mccoyst 15y 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.
jeremysalwen 15y 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 15y ago
  How is that a logical fallacy? That's just a lack of data and an unwillingness to gather it.
  - jeremysalwen 15y 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 15y ago
Great poster, but instead of donation button, you should have a "buy a print" button.
ekianjo 15y 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 15y ago
Great salesmanship tool worksheet!
alttag 15y 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".
- jonah 15y ago
  Back up, but if it goes down again here's a cached copy: http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_A1.pdf http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_...
SneakyBeak 15y ago
Site is down.
- jonah 15y ago
  Copy here: http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_A1.pdf http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_...
deleted 15y ago
[deleted]
Locke1689 15y 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.
- olalonde 15y ago
  Have you read the longer descriptions? http://www.yourlogicalfallacyis.com/appeal-to-authority http://www.yourlogicalfallacyis.com/appeal-to-authority http://www.yourlogicalfallacyis.com/slippery-slope http://www.yourlogicalfallacyis.com/slippery-slope Your concerns seem to be addressed there.
  - Locke1689 15y ago
jiggy2011 15y 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 15y ago
  Reddit has come to love the reference to the straw man fallacy of late.
Cogito 15y 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 15y 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.

81 points by jonah 15y ago

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

jarin 15y 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_fallacies_poster-228887783776402214 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)

eeeeaaii 15y 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.

bunderbunder 15y 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.
- repsilat 15y 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.
  - jiggy2011 15y ago
    I think pointing out a fallacy can sometimes be a good defense against somebody who is insisting that something is a mechanical certainty when it is not.
    - bunderbunder 15y ago
      Yes. But more often's the case that the fearless fallacy hunter fallaciously finds fallibility by fantasizing formality or finality. Thereby committing a fallacy himself in the form of a straw man.
      - jiggy2011 15y ago
        I see what you did there , I think I'm going to use that.
- jiggy2011 15y 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.
JesseR 15y 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_S 15y 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.
- eeeeaaii 15y 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_S 15y 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 15y 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.
- jiggy2011 15y ago
  I think it's impossible to have a rational argument with many Americans if you use the word "communism" anywhere.
  - repsilat 15y ago
    You have to be doubly careful with communism - McCarthyism and the "Red Scare" were clearly a little much, but the trendy counter-reaction tends to be at odds with history. The US government was infiltrated by actual communist spies (to the extent that they practically ran the State Department in the '50s), and it's hard to argue with the hundred million or so it killed in the 20th century. It's easy to say that there have been no properly realised communist societies/states, but an honest account has to hold the idea responsible for the ubiquitous oppression and murder committed by regimes attempting to create them. I won't argue that the Americans you talked to can give a reasoned condemnation of communism, but with its historical baggage the burden tends to swing the other way. It's hard to have a rational argument with a lot of people about Nazism, but it's hard to criticise people for trusting that it's not for them.
mccoyst 15y 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.

jeremysalwen 15y 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 15y ago
How is that a logical fallacy? That's just a lack of data and an unwillingness to gather it.
- jeremysalwen 15y 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 15y ago

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

ekianjo 15y 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 15y ago

Great salesmanship tool worksheet!

alttag 15y 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".

jonah 15y ago
Back up, but if it goes down again here's a cached copy: http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_A1.pdf http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_...

SneakyBeak 15y ago

Site is down.

jonah 15y ago
Copy here: http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_A1.pdf http://dl.dropbox.com/u/1579631/LogicalFallaciesInfographic_...

deleted 15y ago

[deleted]

Locke1689 15y 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.

olalonde 15y ago
Have you read the longer descriptions? http://www.yourlogicalfallacyis.com/appeal-to-authority http://www.yourlogicalfallacyis.com/appeal-to-authority http://www.yourlogicalfallacyis.com/slippery-slope http://www.yourlogicalfallacyis.com/slippery-slope Your concerns seem to be addressed there.
- Locke1689 15y ago

jiggy2011 15y 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 15y ago
Reddit has come to love the reference to the straw man fallacy of late.

Cogito 15y 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 15y 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.