# When are Fallacies false? **URL:** \ **Category:** Great Debates\ **Created:** [October 6, 2008, 8:09pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737 "2008-10-06T20:09:15Z")\ **Posts on this page:** 13\ **Page:** 3
**Author:** ![Blaster\_Master](https://avatars.discourse-cdn.com/v4/letter/b/cab0a1/32.png) [@Blaster\_Master](https://boards.straightdope.com/u/Blaster_Master)\ **Post date:** [October 7, 2008, 6:53pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/41 "2008-10-07T18:53:14Z")
> [@smiling\_bandit](#): > > I think this is basically my point: The “Fallacies” don’t prove the argument on their own, but they can, under some circumstances, be a powerful argument nonetheless. I think I see what you’re saying, let me see if I can clarify. I’ll use the Hitler"ad hominem example you presented. Technically, it’s an invalid argument because the idea can be judged on it’s merits and may be good even though he is the one that presented it. However, from a pragmatic standpoint, we must also realize that someone who has a history of horrible plans for world peace and prosperity is probably less likely to be proposing one that is worthwhile. Is it the second point that you’re addressing? To get it in a scenario that we’re more likely to see, a commercial says that their product is prefered by 3 out of 4 consumers. This is technically argument ad populum; it’s entirely possible that most people like a particular product and it is not the best product available. However, this is still a persuasive argument from a commercial perspective because realistically, if a lot of people use the product it’s probably going to be a pretty good product, or at least a decent one. If that’s the case, then I would agree that, yes these are fallacies in formal logic, but that doesn’t mean they’re not still powerful tools, particularly when you’re talking about things like preferences and society where it’s a lot harder to come up with definitively true premises and logical steps. I also think this is exactly why these fallacies come up so often because we’re use to seeing them used as reasoning in other fields and it just doesn’t seem as natural when they’re not true when applying formal logic. ---
**Author:** ![mswas](https://avatars.discourse-cdn.com/v4/letter/m/e99b99/32.png) [@mswas](https://boards.straightdope.com/u/mswas)\ **Post date:** [October 7, 2008, 6:55pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/42 "2008-10-07T18:55:41Z")
> [@Airman\_Doors\_USAF](#): > > Fallacies are only fallacies when you use them and somebody doesn’t agree with you even if they used them first, or they attack first and you try to refute their arguments. > > In other words, inasmuch as they exist at all they serve only to derail an argument that someone doesn’t like. Other than that, you may fire at leisure and nobody cares. Wow, just wow. This has to go up as one of the most horrible posts ever on this board. “If you’re talking some total bullshit and someone calls you on it, then they are just trying to derail the argument because they’re jealous that they didn’t get to use the bullshit first.” The word ‘fallacy’ is a synonym for falsehood. So fallacies are always false, by definition. If it’s not false, it’s not a fallacy. ---
**Author:** ![CJJ](https://avatars.discourse-cdn.com/v4/letter/c/ecc23a/32.png) [@CJJ](https://boards.straightdope.com/u/CJJ)\ **Post date:** [October 7, 2008, 7:32pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/43 "2008-10-07T19:32:49Z")
> [@mswas](#): > > The word ‘fallacy’ is a synonym for falsehood. So fallacies are always false, by definition. If it’s not false, it’s not a fallacy. I think this needs clarification. Arguments can be described as fallacious, but we normally don’t describe statements, opinions, or ideas this way. “Fallacy” is not a general synonym for “falsehood”, but rather a term for an argumentative form that does not prove the point it is trying to prove–the argument is false, but the premise may not be. Many a fallacious argument has been used to support premises that could be proven true with a sound argument. In fact, declaring something false merely because it is supported by a fallacious argument is itself an informal fallacy (I think this is the basis for the “Straw Man” fallacy). ---
**Author:** ![Gfactor](https://avatars.discourse-cdn.com/v4/letter/g/9de053/32.png) [@Gfactor](https://boards.straightdope.com/u/Gfactor)\ **Post date:** [October 7, 2008, 7:43pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/44 "2008-10-07T19:43:06Z")
> [@CJJ](#): > > “Fallacy” is not a general synonym for “falsehood”, but rather a term for an argumentative form that does not prove the point it is trying to prove–the argument is false, but the premise may not be. Exactly. > [@](#): > > A fallacy is, very generally, an error in reasoning. This differs from a factual error, which is simply being wrong about the facts. To be more specific, a fallacy is an “argument” in which the premises given for the conclusion do not provide the needed degree of support. A deductive fallacy is a deductive argument that is invalid (it is such that it could have all true premises and still have a false conclusion). An inductive fallacy is less formal than a deductive fallacy. They are simply “arguments” which appear to be inductive arguments, but the premises do not provided enough support for the conclusion. In such cases, even if the premises were true, the conclusion would not be more likely to be true. [Fallacies - Nizkor](http://www.nizkor.org/features/fallacies/) > [@](#): > > Early work in informal logic does not favour a systematic attempt to assess the strength and properties of good deductive, inductive, conductive, etc. arguments. Instead, it favours fallacies as a tool in the analysis of informal reasoning. According to traditional accounts, a fallacy is a pattern of poor reasoning which appears to be (and in this sense mimics) a pattern of good reasoning (see Hansen [2002]). Such accounts are problematic, especially because it is difficult to identify when poor reasoning “appears” to be good. What “appears good” to one person may not appear so to another. In assessing ordinary arguments, most contemporary commentators avoid such issues by understanding fallacies more simply, as common patterns of poor reasoning which can usefully be identified in the evaluation of informal reasoning. [Informal Logic (Stanford Encyclopedia of Philosophy)](http://plato.stanford.edu/entries/logic-informal/#Fal) ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [October 7, 2008, 7:59pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/45 "2008-10-07T19:59:53Z")
> [@mswas](#): > > The word ‘fallacy’ is a synonym for falsehood. So fallacies are always false, by definition. If it’s not false, it’s not a fallacy. Wow. There’s a fallacious argument right there! B is a synonym for A. Therefore, anything that is not A, is not B. For example: “Dribble” is a synonym for “drool.” So if a basketball player is not drooling, he’s not dribbling. The problem is that the word “fallacy” has multiple meanings. (Look it up in the dictionary if you don’t believe me.) It can mean “falsehood,” but in the context of logic (i.e. **logical** fallacies), it refers to an **invalid** form of argument. ---
**Author:** ![mswas](https://avatars.discourse-cdn.com/v4/letter/m/e99b99/32.png) [@mswas](https://boards.straightdope.com/u/mswas)\ **Post date:** [October 7, 2008, 8:04pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/46 "2008-10-07T20:04:48Z")
Right and an ‘invalid form of argument’ refers to a ‘false argument’. See how that works? A fallacy is false by definition. The conclusions might be correct, but that’s irrelevant to whether or not the argument is false. Fallacies are always false as defined. This is a stupid thread. ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [October 7, 2008, 8:10pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/47 "2008-10-07T20:10:13Z")
> [@mswas](#): > > Right and an ‘invalid form of argument’ refers to a ‘false argument’. See how that works? A fallacy is false by definition. The conclusions might be correct, but that’s irrelevant to whether or not the argument is false. Fallacies are always false as defined. This is a stupid thread. But the very phrase “false argument” gives rise to all sorts of confusion. So logicians don’t classify arguments as TRUE or FALSE, but rather as VALID or INVALID. ---
**Author:** ![tomndebb](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@tomndebb](https://boards.straightdope.com/u/tomndebb)\ **Post date:** [October 7, 2008, 8:17pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/48 "2008-10-07T20:17:30Z")
> [@mswas](#): > > Wow, just wow. This has to go up as one of the most horrible posts ever on this board. > > “If you’re talking some total bullshit and someone calls you on it, then they are just trying to derail the argument because they’re jealous that they didn’t get to use the bullshit first.” > > The word ‘fallacy’ is a synonym for falsehood. So fallacies are always false, by definition. If it’s not false, it’s not a fallacy. You did not notice that by providing an erroneous complaint against that post, you drove your post to a lower position on the scale of quality? 😃 Regardless of any potential errors in Airman’s post, the claim that fallacy is a synonym for false hood fails on the level of historical etymology and current usage. Drawing (from that error) the conclusion that an error in logic is always false (even though such errors may simply indicate an incorrect path to a correct conclusion) is, itself, incredibly incorrect. (See any of the other discussions of the meaning of fallacy in this thread. Further, you have committed the same error of ambiguity that was posted earlier. To say that a fallacy is false is meaningless. Since a fallacy is a method of argumerntation or logic and not an idea or object of its own, it cannot actually be false, itself, so your sentence needs to be clarified before we can do justice shredding it. If a fallacy occurs, just what is it that is false? Is it the conclusion (which may be true despite the error in logic)? Is it the speaker (to whom the label “false” does not particularly apply as that person remains a person rgardless of his or her errors in logic)? Clarity and accuracy, **mswas**. Strive for them. (It did not really help your position that you were clearly whoooshed by Airman’s irony.) ---
**Author:** ![smiling\_bandit](https://avatars.discourse-cdn.com/v4/letter/s/e9a140/32.png) [@smiling\_bandit](https://boards.straightdope.com/u/smiling_bandit)\ **Post date:** [October 7, 2008, 8:21pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/49 "2008-10-07T20:21:33Z")
> [@Blaster\_Master](#): > > I think I see what you’re saying, let me see if I can clarify. I’ll use the Hitler"ad hominem example you presented. Technically, it’s an invalid argument because the idea can be judged on it’s merits and may be good even though he is the one that presented it. However, from a pragmatic standpoint, we must also realize that someone who has a history of horrible plans for world peace and prosperity is probably less likely to be proposing one that is worthwhile. Is it the second point that you’re addressing? Yeah. I think a more technical way to say it would be that “Many logical fallacies are expressions of common sense delivering a probabilistically-derived meaning from experience.” ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [October 7, 2008, 8:25pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/50 "2008-10-07T20:25:11Z")
> [@smiling\_bandit](#): > > I think this is basically my point: The “Fallacies” don’t prove the argument on their own, but they can, under some circumstances, be a powerful argument nonetheless. Oh, there’s no denying a lot of fallacious arguments are powerful crowd-pleasers and rhetorical winners. That’s why people use them. I’d hesitate to call them “powerful _arguments_” though, unless you mean in a super-villain kind of sense. To me, a powerful argument is _neccesarily_ a sound one, too. ---
**Author:** ![Blaster\_Master](https://avatars.discourse-cdn.com/v4/letter/b/cab0a1/32.png) [@Blaster\_Master](https://boards.straightdope.com/u/Blaster_Master)\ **Post date:** [October 7, 2008, 9:14pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/51 "2008-10-07T21:14:25Z")
> [@smiling\_bandit](#): > > Yeah. I think a more technical way to say it would be that “Many logical fallacies are expressions of common sense delivering a probabilistically-derived meaning from experience.” Perhaps a bit heavy-handed on the large words, but I think most of us can agree with that. ---
**Author:** ![CJJ](https://avatars.discourse-cdn.com/v4/letter/c/ecc23a/32.png) [@CJJ](https://boards.straightdope.com/u/CJJ)\ **Post date:** [October 7, 2008, 9:26pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/52 "2008-10-07T21:26:35Z")
> [@smiling\_bandit](#): > > Yeah. I think a more technical way to say it would be that “Many logical fallacies are expressions of common sense delivering a probabilistically-derived meaning from experience.” I think a shorter way to say this is “Many logical fallacies are inductive”. Informal fallacies certainly rely on induction–if “slippery slope” is true in these cases, it’s true in all cases–but formal fallacies are arguments that are invalid because of a clear error in the rules of logic. Formal fallacies are somewhat analogous to an algebraic error made in solving a math problem (e.g. inadvertently dividing by zero in the famous “proof” that 2=1). Informal fallacies are more like trying to solve a linear equation with the quadratic formula. ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [October 7, 2008, 9:29pm UTC](https://boards.straightdope.com/t/when-are-fallacies-false/466737/53 "2008-10-07T21:29:30Z")
> [@smiling\_bandit](#): > > One thing I’ve noted about [logical fallacies](http://en.wikipedia.org/wiki/Logical_fallacies)… they ain’t. At least not all of them all the time. Oh sure, they’re an intellectual and emotional shorthand and often do mess things up, but contained within them is an awful lot of good sense, which enables people to make reasonable judgements without having to think through from first principles and acquiring all the facts (which nobody can do anyway). > > For example, Ad Hominem is a pretty good one. Maybe Hitler suddenly pops up with a program for world peace and prosperity, but you’d be a fool to listen to him. It’s most suspect where the counter-arguer is biased or irrational. > > For example, **Diogenes the Cynic** can be counted on to interject several lines about Bush is the avatar of sin and stupidity incarnate, or how McCain is a nightmarish fiend of unrelenting horror, into pretty much everything. It doesn’t matter what the thread is, seemingly Dio will find to way to say how much he hates anyone and everything which is not his political pet. His arguments are unreliable because he views everything through the lens of “Is My Politics == Good” and “Is Not My Politics == Bad”. > Of course, some of them just plain suck. You’ve raised a really good topic, **smiling bandit**. It’s important to note that there’s a difference between a logical fallacy and a rhetorical fallacy. You can Google both and find good sources, like Infidels for the former and Silva Rhetoricae for the latter. A logical fallacy is a fallacy of rule. For example, there are rules regarding the drawing of inferences in most logics systems. In first order predicate logic — the logic familiar to most of us — modus ponens is a rule, while affirmation of the consequent is a fallacy. Modus ponens says that if an inference, B, is to be drawn from an assertion, A, then if A is true, B is also true. But affirmation of the consequent is supported by no rule, and says that if an inference, B, is to be drawn from an assertion, A, then if B is true, A is also true. Here’s how they look using “-\>” to mean “implies”: Modus ponens: A -\> B: A is true, therefore B is true. Affirmation of the consequent: A -\> B: B is true, therefore A is true. And here are examples: Modus ponens: If I have a hundred dollars, I can buy a cup of coffee. I do indeed have a hundred dollars; therefore, I can buy a cup of coffee. Affirmation of the consequent: If I have a hundred dollars, I can buy a cup of coffee. I can indeed buy a cup of coffee; therefore, I have a hundred dollars. The fallacy lies in the fact that B is presupposing things that A has not declared. You can buy a cup of coffee (as of this writing) even if you have far less than a hundred dollars. A logical fallacy always destroys an argument. Rhetorical fallacies are different. You cited one — ad hominem — in your OP. Fallacies of rhetoric do not necessarily debunk an argument, but they in no way assist one. So, for example, if you’re writing out a list of reasons why we should use the gold standard, then “Number 5, you’re an idiot” would not be considered by a reasonable person to be supportive of what you’re trying to prove. So, to sum up… if an argument of logic is made, then a fallacy destroys it. But if an argument of rhetoric is made, then a fallacy does not support it. [Previous page](https://boards.straightdope.com/t/when-are-fallacies-false/466737.md?page=2)