I just registered http://worstargumentintheworld.com - it redirects to this post, and should be available shortly. Much easier to mention in conversation when other people use this argument, and don't believe it's a "real thing."
Great piece of work, Yvain - it's now on my list of all-time favorite LW posts.
I just registered http://worstargumentintheworld.com - it redirects to this post, and should be available shortly. Much easier to mention in conversation when other people use this argument, and don't believe it's a "real thing."
"Real things" have their own domain. I registered this domain, therefore...
Hahaha, nice.
I was imagining a situation in which someone makes an argument of this type, you say something along the lines of "that's a great example of the 'Worst Argument in the World'," and the person replies "you just made that up..." or "that's just your opinion..."
Providing a pre-existing URL that links to a well-written page created by a third-party is a form of evidence that shifts "Worst Argument in the World" from something that feels like an opinion to the title of a logical fallacy. That can be quite useful in certain circumstances.
Exactly! Logical fallacies are bad, and the Worst Argument in the World is a logical fallacy!
(Actually valid because it's a typical, central logical fallacy, not an edge case. If you'd asked me to list the most common logical fallacies even before I saw this post, I'd hope that I'd remember to put argument-by-categorization-of-atypical-cases into the top 10.)
and how can you be sure any given instance of it is not itself an atypical case, that ought not to be compared against the obviously bad =murder or =hitler cases?
By checking.
If I debate with someone, he tells me something like "abortion is murder", I point him to http://worstargumentintheworld.com/ and he takes the pain to read the article AND the discussion and sees why/how the domain was registered, I would claim victory in "raising the sanity waterline".
The argument authority of having a domain pointing to may (I hope it'll) increase the chance the person does at least read a bit of the page instead of discarding it, but I doubt it'll do anything into making him/her accepting that the argument is wrong behind that.
Yvain, here is a challenge. Many of your examples are weak versions of strong right-wing arguments that you do not accept. (by your remark about Schelling fences, it seems you're aware of this). I challenge you to replace each of these examples with a weak version of a strong left-wing argument that you do accept. Since policy debates should not appear one-sided, there should be no shortage of weak arguments "on your side." And it would be an interesting kind of ideological Turing test.
Perhaps I'm wrong about "what side you're on" and you already accept the strong right-wing arguments. In which case you got me, well done!
"X is in a category whose archetypal member has certain features. Therefore, we should judge X as if it also had those features, even though it doesn't."
This is the original definition given for TWAITW. Note that the examples Yvain gave all had the form of: "X is in a category whose archetypal member has certain negative features. Therefore, we should judge X as if it also had those features." However, working with the explicit definition outlined by Yvain, as opposed to the implicit definition used by Yvain, we can easily conjure liberal examples:
Other liberal examples, using Yvain's implicit definition:
However, I am not entirely sure if our capacity to conjure examples matters.
Edit: Changed the free speech examples.
I very much like "Abortion is a medical procedure". It's actually a believable WAitW to make, and has the admirable feature that it completely ignores every aspect of abortion relevant to the debate.
I think the "free speech" examples don't quite have the right form: the central question probably is whether or not pornography or flag burning is free speech, and the conclusion "Flag burning is free speech, therefore it should be legal" is valid if you accept the premise.
I really like "Abortion is a medical procedure". I suspect that we could remove some of the mind-killing by presenting the examples in pairs:
Hmm, creating these pairs is harder than I thought.
The challenge is an interesting exercise, and I will try to think up some examples, but your comment also contains an implied accusation which I'd like to respond to first.
By my count, this post includes critiques of four weak right-wing arguments (abortion, euthanasia, taxation, affirmative action) and three weak left-wing arguments (eugenics, sexism, capital punishment). As far as I know, neither side thinks MLK was a criminal. That means I'm 4-3, ie as balanced as it's mathematically possible to get while seven remains an odd number.
And I think the responses I see below justify my choice of examples. Shminux says the pro-choice converse of "abortion is murder" would be "forced pregnancy is slavery"; TGM suggests below it "denying euthanasia is torture". These would be excellent examples of TWAITW if anyone ever asserted them which as far as I know no one ever has. Meanwhile, I continue to walk past signs saying "Abortion Is Murder!" on my way to work every day. I don't know who exactly it would be helping to give "Forced Pregnancy Is Slavery" equal billing with "Abortion Is Murder" here and let my readers conclude that...
If you can think of left-wing WAITWs that are as well-known and catchy as "abortion is murder!", I will happily edit the post to include them
"Property is theft"
Is an example of the left using the WAITW.
American liberals aren't that kind of left. And Proudhon did mean "property is wrong for the same class of reasons theft is".
As a leftist, this seems like a useful exercise. Here are a few claims I've heard more than once from fellow leftists that might qualify.
A fetus is a clump of cells.
Corporations are not people.
Money is not speech.
"Profiling is discrimination"
"Racial profiling is racist."
While I can see this argument apply as a sort of justifiable use when humans are doing such profiling, though even in that case I think it should be used sometimes, I find it a bit absurd when applied to say data mining systems. Are we to apply Bayesian reasoning to everything except predictors tied to certain sacralized human traits like gender, dress, class, race, religion and origin? Why don't we feel averse applying it to say age?
"Growth for growth's sake is the ideology of the cancer cell."
To avoid nitpicking that cancer cells have no ideology, I will point out that if they did, they would share the ideology with all life forms on the planet.
"Growth for growth's sake is the ideology of life!"
Doesn't sound as evil no?
I think the difference is that the right wing examples are examples of core beliefs that many stereotypical conservatives believe. Thus leftists feel like they are scoring points when they read it. The left examples, however, aren't really core beliefs of the Democratic party. Democrats may lean against capital punishment, but no presidential candidate in my memory has made that a core tenant of eir campaign.
I also think it's wildly generous to suggest eugenics as a leftist issue. I can't remember ever hearing someone seriously suggest that genetic engineering is eugenics. And typically, it's conservatives who are opposed to genetic engineering, generally on the grounds of playing God.
And when I was reading it, MLK got lumped in with conservatives for a number of reasons. First, the strong conservative examples primed me to put it there. Second, the civil rights act was largely pushed for by a Democratic legislature and president. Lastly, African Americans tend to line up with democrats in modern demographics.
The best leftist example I could come up with is "Meat is murder". I think that merits including. Or mixing in with the abortion one.
I have the impression that (1) when people post things in LW that are politically leftish, it's quite common for them to get a response along these lines -- complaining about leftward bias and suggesting that it should be addressed by a deliberate injection of rightward bias to compensate -- whereas (2) when people post things in LW that are politically rightish, they basically never receive such responses.
I have no statistics or anything to back this up, and it's not clear that there's any feasible way to get (or informatively fail to get) them, so I'd be interested in other opinions about whether this asymmetry is real.
If it is real, it seems to me quite interesting.
(One possible explanation, if it's real, would be that leftish views are much more common here than rightish ones, so that people with rightish views feel ill-treated and want the balance redressed. Except that I think I see distinctly more rightish than leftish political commentary here, and the rightish stuff more often gets large numbers of upvotes. I suppose it's possible that what we have here is a lot of slightly leftish people and a smaller number of rightish ones who feel more strongly. Again, this is probably hard to get a good handle on and I'd be interested in others' impressions.)
Well right wing people are almost certainly a minority here, but don't forget that makes such positions convenient for hipster fun. Some LWers who argue for right wing positions have stated that they feel more and more unwelcome in the past few months. Not only that I think they make a good case for pro left bias being very prevasive on LessWrong. I think what you are seeing is some users trying to correct for it.
I find the fact that both people who see themselves as left leaning and those who see themselves as right leaning suddenly feel there is favouritism for those who disagree with them is a much more worrying sign. I think this is what being on one side of a tribal conflict looks like from the inside.
The most popular political view, at least according to the much-maligned categories on the survey, was liberalism, with 376 adherents and 34.5% of the vote. Libertarianism followed at 352 (32.3%), then socialism at 290 (26.6%), conservativism at 30 (2.8%) and communism at 5 (.5%).
-- Yvain's 2011 survey
I have the impression that (1) when people post things in LW that are politically leftish, it's quite common for them to get a response along these lines -- complaining about leftward bias and suggesting that it should be addressed by a deliberate injection of rightward bias to compensate -- whereas (2) when people post things in LW that are politically rightish, they basically never receive such responses.
My explanation of this perception is that posters, in general, know better than to post rightish things at LW unless they are correct. Every now and then you get a new Objectivist who gets downvoted because they aren't discussing things at a high enough level.
Lots of beliefs that are common on LW are uncomfortable for the stereotypical leftist- like human biodiversity in general. To see someone brazenly state that, yes, there is a difference in measured IQ between the races and that reflects reality rather than our inability to design tests properly, or that men and women are actually neurologically distinct, will seem like a "not my tribe" signal to the stereotypical leftist- but people here don't hold that opinion (as far as I can tell) because of racial or sexual enmity, but because they put evidence above wishful thinking and correct beliefs above politeness.
But now imagine that for the stereotypical rightist. How big of a "not my tribe" signal is atheist materialism and evolution?
I am thinking that one possible asymetry between "the left" and "the right" is that the former is a rather homogenous group, while the latter is heterogenous. The left generally means socialist(-ish), and the right generally means non-socialist. The left is a fuzzy blob in the concept-space, the right seems like a label for points outside of this blob.
As an example, both Ayn Rand and Chesterton would be examples of "the right". What exactly do they have in common? (Religion: the best thing ever, or the worst thing ever? Individual or community? Mystery or reason? The great future or the great past? Selfishness or selflessness? Should women be allowed as leaders? Etc.) The common trait that classifies them both as "the right" is the fact that neither of them is a socialist.
Well, I could also says that neither of them "considers hinduism the best thing ever"... but why should that information be used to classify them? Well, for a hinduist that would be an important information. Then it follows that classifying many diverse views under one label of "the right" makes sense to you mostly if you are a socialist. (Or if being ver...
I am thinking that one possible asymetry between "the left" and "the right" is that the former is a rather homogenous group, while the latter is heterogenous. [...] The left is a fuzzy blob in the concept-space, the right seems like a label for points outside of this blob.
Beware the out-group homogeneity effect. People tend to see their own group as more heterogeneous than other groups, as differences that look small from far away look bigger up close.
With left and right, I have also heard the exact opposite claim: that the "right" represents a narrower, more coherent group. In the US, the "right" is based in the dominant, mainstream social group (sometimes called "real America"), drawing disproportionately from people who are white, male, Christian, relatively well-off, straight, etc., while the "left" is a coalition of the various groups that are left out of "real America" for one reason or another. Alternatively, conservatives are the people who support the existing social order and want to keep things roughly how they are; liberals are the ones who want change - and there are more degrees of freedom in changing things than in keeping things the same.
This is an interesting point, that one about the left being more homogeneous than the right. I am not sure whether to believe it, so let me present some objections that I can think of, without evaluating their merit.
A) Assuming the left is indeed more homogeneous, isn't it true just because of greater variability of right between different countries, with a typical single country's right being as homogeneous as the same country's left? (The objection hasn't a particularly strong bearing on the perceived LW left/right imbalance, but may be relevant to the more general question of how the categories of left and right are defined.)
The left generally means socialist(-ish), and the right generally means non-socialist.
B) This may not be accurate; beware availability heuristics.
Environmentalists aren't necessarily socialists as their opinions about the optimal economic order aren't the defining part of their ideology and may differ. Yet the environmentalists are usually classified on the left. Anarchists aren't necessarily socialists; many of them oppose any form of organised society, while archetypal socialism is a very organised society, from many points of view more than market ca...
I've posted such complaints about left wing bias, so I'll elaborate on my impressions.
I perceive the left wing comments come with much more of an implicit assumption by the poster, and the respondents to it, of the moral superiority of left wing positions, and that all attending will see it the same way.
Most of the non left wing views don't seem to me to come with that presumption on the part of the speaker that everyone here shares their moral evaluation. If anything, the tone is of someone who expects to be taken as a crank.
The liberals are more generally accustomed to being in an ideologically homogeneous environment while the libertarians are accustomed to being in the minority, and both speak with a tone appropriate to the general environment, and not to the particular environment here, where liberals and libertarians are equally represented.
For my part, I also find instances where the absent conservatives are caricatured and snickered at, again with the presumption that all right thinking folk agree, and the bile rises in the gorge, and I feel the need to respond.
Isn't that reasonable though? If you're a X-winger, isn't the whole point that X-wing positions are in fact morally superior?
Morally superior perhaps, but they lack the hull plating and durability to survive ongoing combat and the offensive payload pales in comparison to what the Y-wing can deliver.
The Y-wing was an outdated piece of junk even by the Battle of Yvain; that's why the Rebels had it at all. The X-wing's proton torpedoes deliver the hurt when necessary (just ask Tarkin or Ysanne Isard), and if you want more than that, well, that's what the B-wings are for... Between them and the A-wing, there is simply no role for Y-wings at any point - except cannon bait!
What is the strong version of "taxation is theft", for example? I can recall arguments against taxation stronger than this, of course, but none of them I would consider a version of the "taxation is theft" argument.
As for the arguments mentioned in the OP, "taxation is theft", "abortion is murder" and "euthanasia is murder" are typically right-wing, "affirmative action is racist" is also probably right-wing (although general accusations of racism fit better into the left wing arsenal) while "capital punishment is murder", "ev-psych is sexist" and "genetic engineering is eugenics" sound quite leftist to me. Not sure about "M.L.King was a criminal", but the examples seem balanced with respect to the stereotypical left/right division. With respect to Yvain's opinions the choice might be less balanced, of course.
I don't understand how you get from "policy debates should not appear one-sided" to "there should be no shortage of weak arguments 'on your side'". Especially if you replace the latter with "there should be no shortage of weak arguments of this sort on your side" -- which is necessary for the challenge to be appropriate -- since there could be correlations between a person's political position and which sorts of fallacies are most likely to infect their thinking.
In particular, I predict WAITW use to be correlated with explicit endorsement of sanctity-based rather than harm-based moral values, and we've recently been talking about how that might differ between political groups.
I think this is because of the way you're deconstructing the arguments. In each case, the features you identify which supposedly make us dislike the arcetypal cases are harm-based features. Someone who believed in sanctity instead might identify the category as a value in itself. Attempts to ascribe utilitarian-style values to them, which they supposedly miss the local inapplicability of, risks ignoring what they actually value.
If people genuinely do think murder is wrong simply because it is murder, rather than because it causes harm, then this is not a bad argument.
Keeping your principle of ignoring meta-ethical baggage, dis-valuing harm only requires one first principle, whereas dis-valuing murder, theft, elephants, etc require an independent (and apparently arbitrary) decision at each concept. Further, it's very suspicious that this supposedly arbitrary decision almost always picks out actions that are often harmful when there are so very many things one could arbitrarily decide to dislike.
I have tried constructing a pro-choice example similar to "Abortion is murder!" ("Forced pregnancy is slavery!"???), but it ended up pretty unconvincing. Hopefully someone can do better:
Leaving rape cases aside, the archetypal example is an unwanted teenage pregnancy due to defective or improperly used birth control or simply an accident. Forcing her into letting the embryo develop into a fetus and eventually into a human baby would likely make the woman significantly worse off in the long run, financially, physically and/or emotionally, so she should have an option of terminating the pregnancy.
An example a pro-life person thinks of: aborting a healthy fetus, possibly in the second trimester, as a habitual birth control method.
I find "Forced parenthood is slavery!" to be pretty convincing, actually. Though I may be prejudiced by having grown up around a Libertarian father (now, alas, more Republican(!??)) who went about proclaiming that jury duty was slavery.
It may be a word error - I don't think it is, "Evolutionary psychology is riddled with false claims produced by sexist male scientists and rationalized by the scientists even though the claims are not at all well-supported compared to nonsexist alternatives" is a coherent and meaningful description of a way the universe could be but isn't, and is therefore false, not a word error - but if so, it's a word-error made by stereotypically left-wing people like Lewontin and Gould who were explicitly political in their criticism, not a word-error made by any right-wing scientists I can think of offhand.
In general, we should be careful about dismissing claims as meaningless or incoherent, when often only a very reasonable and realistic amount of charity is required to reinterpret the claim as meaningful and false - most people are trying to be meaningful most of the time, even when they're rationalizing a wrong position. Only people who've gotten in a lot more trouble than that are actively trying to avoid letting their arguments be meaningful. And meaningless claims can be dismissed immediately, without bringing forth evidence or counterobservations; meaningful false claims require more demonstration to show they're false. So when somebody brings a false claim, and you dismiss it as meaningless, you're actually being significantly logically rude to them - putting in less effort than they're investing - it takes more effort to bring forth a meaningful false claim than to call something 'meaningless'.
I dislike accusations of sexism as much as the next guy, but in the last year or two I have started to think that ev-psych is way overconfident. The coarse grained explanation is that ev-psych seems to be "softer" than regular psychology, which itself is "softer" than medicine, and we all know what percentage of medical findings are wrong. I'd be curious to learn what other LWers think about this, especially you, because your writings got me interested in ev-psych in the first place.
No, Hitler didn't make arguments, he made assertions; and you know what else was an assertion? Your comment!
I love the article, but this is a bad name for a fallacy, as it hinders neutral discussion of its relative badness compared to other fallacies.
If I could pick a name, I'd probably choose something like "tainting categorization".
it hinders neutral discussion of its relative badness compared to other fallacies
Not only that, but it is also non-descriptive.
I don't see what this has to do with "loss aversion" (the phenomenon where people think losing a dollar is worse than failing to gain a dollar they could have gained), though that's of course a tangential matter.
The point here is -- and I say this with all due respect -- it looks to me like you're rationalizing a decision made for other reasons. What's really going on here, it seems to me, is that, since you're lucky enough to be part of a physical community of "similar" people (in which, of course, you happen to have high status), your brain thinks they are the ones who "really matter" -- as opposed to abstract characters on the internet who weren't part of the ancestral environment (and who never fail to critique you whenever they can).
That doesn't change the fact that this is is an online community, and as such, is for us abstract characters, not your real-life dinner companions. You should be taking advice from the latter about running this site to about the same extent that Alicorn should be taking advice from this site about how to run her dinner parties.
Vaniver and DaFranker have both offered sensible, practical, down-to-earth advice. I, on the other hand, have one word for you: Airship.
signal your outgroup hatred with a downvote and move on.
Downvoted because I don't find it appropriate to uncharitably interpret the meaning of any downvotes one receives, and certainly not out loud and in advance.
It's bad when people use the dictionary to make political arguments, but it's worse when they write their own dictionary. For example:
Normal people define "selfishness" as "taking care of oneself, even if that means hurting other people." Objectivists define "selfishness" as "taking care of oneself, but never hurting other people." Hence, selfishness can never morally objectionable.
Normal people define "sexism" as "unfair treatment of a person based on their sex." Feminists define "sexism" as "unfair treatment of a person based on their sex, but it only counts if their sex has been historically disadvantaged." Hence, men can never be victims of sexism.
Normal people define "freedom" as "the ability to do a lot of stuff." Catholics define freedom as "the ability to do as God wishes." Hence, laws enforcing Catholic norms are pro-freedom.
Objectivists define "selfishness" as "taking care of oneself, but never hurting other people."
Not to mention that they define "hurting" as "damaging or destroying other's life, health or property by direct action" where normal people understand the word much more broadly.
Normal people define "true" as "good enough; not worth looking at too closely". Nerds define "true" as "irrefutable even by the highest-level nerd you are likely to encounter in this context." Hence more or less all of Western philosophy, theology, science, etc.; and hence normal people's acceptance that contradictory things can be "true" at the same time.
(Yes, I'm problematizing your contrast between various groups you dislike and "normal people".)
and hence normal people's acceptance that nerd-contradictory things can be normal-"true" at the same time.
Namespaced that for you.
Long time ago, me and my sockpuppet lonelygirl15, we was scrollin' down a long and boring thread. All of a sudden, there shined a shiny admin... in the middle... of the thread.
And he said, "Give a reason for your views, or I'll ban you, troll."
Well me and lonely, we looked at each other, and we each said... "Okay."
And we said the first thing that came to our heads, Just so happened to be, The Worst Argument in the World, it was the Worst Argument in the World.
Look into my brain and it's easy to see This A is B and that B is C, So this A is C. My heuristic isn't justified But I know it's right 'cause of how it feels From the inside...
Related to: Leaky Generalizations, Replace the Symbol With The Substance, Sneaking In Connotations
David Stove once ran a contest to find the Worst Argument In The World, but he awarded the prize to his own entry, and one that shored up his politics to boot. It hardly seems like an objective process.
If he can unilaterally declare a Worst Argument, then so can I. I declare the Worst Argument In The World to be this: "X is in a category whose archetypal member gives us a certain emotional reaction. Therefore, we should apply that emotional reaction to X, even though it is not a central category member."
Call it the Noncentral Fallacy. It sounds dumb when you put it like that. Who even does that, anyway?
It sounds dumb only because we are talking soberly of categories and features. As soon as the argument gets framed in terms of words, it becomes so powerful that somewhere between many and most of the bad arguments in politics, philosophy and culture take some form of the noncentral fallacy. Before we get to those, let's look at a simpler example.
Suppose someone wants to build a statue honoring Martin Luther King Jr. for his nonviolent resistance to racism. An opponent of the statue objects: "But Martin Luther King was a criminal!"
Any historian can confirm this is correct. A criminal is technically someone who breaks the law, and King knowingly broke a law against peaceful anti-segregation protest - hence his famous Letter from Birmingham Jail.
But in this case calling Martin Luther King a criminal is the noncentral. The archetypal criminal is a mugger or bank robber. He is driven only by greed, preys on the innocent, and weakens the fabric of society. Since we don't like these things, calling someone a "criminal" naturally lowers our opinion of them.
The opponent is saying "Because you don't like criminals, and Martin Luther King is a criminal, you should stop liking Martin Luther King." But King doesn't share the important criminal features of being driven by greed, preying on the innocent, or weakening the fabric of society that made us dislike criminals in the first place. Therefore, even though he is a criminal, there is no reason to dislike King.
This all seems so nice and logical when it's presented in this format. Unfortunately, it's also one hundred percent contrary to instinct: the urge is to respond "Martin Luther King? A criminal? No he wasn't! You take that back!" This is why the noncentral is so successful. As soon as you do that you've fallen into their trap. Your argument is no longer about whether you should build a statue, it's about whether King was a criminal. Since he was, you have now lost the argument.
Ideally, you should just be able to say "Well, King was the good kind of criminal." But that seems pretty tough as a debating maneuver, and it may be even harder in some of the cases where the noncentral Fallacy is commonly used.
Now I want to list some of these cases. Many will be political1, for which I apologize, but it's hard to separate out a bad argument from its specific instantiations. None of these examples are meant to imply that the position they support is wrong (and in fact I myself hold some of them). They only show that certain particular arguments for the position are flawed, such as:
"Abortion is murder!" The archetypal murder is Charles Manson breaking into your house and shooting you. This sort of murder is bad for a number of reasons: you prefer not to die, you have various thoughts and hopes and dreams that would be snuffed out, your family and friends would be heartbroken, and the rest of society has to live in fear until Manson gets caught. If you define murder as "killing another human being", then abortion is technically murder. But it has none of the downsides of murder Charles Manson style. Although you can criticize abortion for many reasons, insofar as "abortion is murder" is an invitation to apply one's feelings in the Manson case directly to the abortion case, it ignores the latter's lack of the features that generated those intuitions in the first place2.
"Genetic engineering to cure diseases is eugenics!" Okay, you've got me there: since eugenics means "trying to improve the gene pool" that's clearly right. But what's wrong with eugenics? "What's wrong with eugenics? Hitler did eugenics! Those unethical scientists in the 1950s who sterilized black women without their consent did eugenics!" "And what was wrong with what Hitler and those unethical scientists did?" "What do you mean, what was wrong with them? Hitler killed millions of people! Those unethical scientists ruined people's lives." "And does using genetic engineering to cure diseases kill millions of people, or ruin anyone's life?" "Well...not really." "Then what's wrong with it?" "It's eugenics!"
"Evolutionary psychology is sexist!" If you define "sexist" as "believing in some kind of difference between the sexes", this is true of at least some evo psych. For example, Bateman's Principle states that in species where females invest more energy in producing offspring, mating behavior will involve males pursuing females; this posits a natural psychological difference between the sexes. "Right, so you admit it's sexist!" "And why exactly is sexism bad?" "Because sexism claims that men are better than women and that women should have fewer rights!" "Does Bateman's principle claim that men are better than women, or that women should have fewer rights?" "Well...not really." "Then what's wrong with it?" "It's sexist!"
A second, subtler use of the noncentral fallacy goes like this: "X is in a category whose archetypal member gives us an emotional reaction. Therefore, we should apply that same emotional reaction to X even if X gives some benefit that outweighs the harm."
"Capital punishment is murder!" Charles Manson-style murder is solely harmful. This kind of murder produces really strong negative feelings. The proponents of capital punishment believe that it might decrease crime, or have some other attending benefits. In other words, they believe it's "the good kind of murder"3, just like the introductory example concluded that Martin Luther King was "the good kind of criminal". But since normal murder is so taboo, it's really hard to take the phrase "the good kind of murder" seriously, and just mentioning the word "murder" can call up exactly the same amount of negative feelings we get from the textbook example.
"Affirmative action is racist!" True if you define racism as "favoring certain people based on their race", but once again, our immediate negative reaction to the archetypal example of racism (the Ku Klux Klan) cannot be generalized to an immediate negative reaction to affirmative action. Before we generalize it, we have to check first that the problems that make us hate the Ku Klux Klan (violence, humiliation, divisiveness, lack of a meritocratic society) are still there. Then, even if we do find that some of the problems persist (like disruption of meritocracy, for example) we have to prove that it doesn't produce benefits that outweigh these harms.
"Taxation is theft!" True if you define theft as "taking someone else's money regardless of their consent", but though the archetypal case of theft (breaking into someone's house and stealing their jewels) has nothing to recommend it, taxation (arguably) does. In the archetypal case, theft is both unjust and socially detrimental. Taxation keeps the first disadvantage, but arguably subverts the second disadvantage if you believe being able to fund a government has greater social value than leaving money in the hands of those who earned it. The question then hinges on the relative importance of these disadvantages. Therefore, you can't dismiss taxation without a second thought just because you have a natural disgust reaction to theft in general. You would also have to prove that the supposed benefits of this form of theft don't outweigh the costs.
Now, because most arguments are rapid-fire debate-club style, sometimes it's still useful to say "Taxation isn't theft!" At least it beats saying "Taxation is theft but nevertheless good", then having the other side say "Apparently my worthy opponent thinks that theft can be good; we here on this side would like to bravely take a stance against theft", and then having the moderator call time before you can explain yourself. If you're in a debate club, do what you have to do. But if you have the luxury of philosophical clarity, you would do better to forswear the Dark Arts and look a little deeper into what's going on.
Are there ever cases in which this argument pattern can be useful? Yes. For example, it may be a groping attempt to suggest a Schelling fence; for example, a principle that one must never commit theft even when it would be beneficial because that would make it harder to distinguish and oppose the really bad kinds of theft. Or it can be an attempt to spark conversation by pointing out a potential contradiction: for example "Have you noticed that taxation really does contain some of the features you dislike about more typical instances of theft? Maybe you never even thought about that before? Why do your moral intuitions differ in these two cases? Aren't you being kind of hypocritical?" But this usage seems pretty limited - once your interlocutor says "Yes, I considered that, but the two situations are different for reasons X, Y, and Z" the conversation needs to move on; there's not much point in continuing to insist "But it's theft!"
But in most cases, I think this is more of an emotional argument, or even an argument from "You would look silly saying that". You really can't say "Oh, he's the good kind of criminal", and so if you have a potentially judgmental audience and not much time to explain yourself, you're pretty trapped. You have been forced to round to the archetypal example of that word and subtract exactly the information that's most relevant.
But in all other cases, the proper response to being asked to subtract relevant information is "No, why should I?" - and that's why this is the worst argument in the world.
Footnotes
1: On advice from the community, I have deliberately included three mostly-liberal examples and three-mostly conservative examples, so save yourself the trouble of counting them up and trying to speculate on this article's biases.
2: This should be distinguished from deontology, the belief that there is some provable moral principle about how you can never murder. I don't think this is too important a point to make, because only a tiny fraction of the people who debate these issues have thought that far ahead, and also because my personal and admittedly controversial opinion is that much of deontology is just an attempt to formalize and justify this fallacy.
3: Some people "solve" this problem by saying that "murder" only refers to "non-lawful killing", which is exactly as creative a solution as redefining "criminal" to mean "person who breaks the law and is not Martin Luther King." Identifying the noncentral fallacy is a more complete solution: for example, it covers the related (mostly sarcastic) objection that "imprisonment is kidnapping".
4: EDIT 8/2013: I've edited this article a bit after getting some feedback and complaints. In particular I tried to remove some LW jargon which turned off some people who were being linked to this article but were unfamiliar with the rest of the site.
5: EDIT 8/2013: The other complaint I kept getting is that this is an uninteresting restatement of some other fallacy (no one can agree which, but poisoning the well comes up particularly often). The question doesn't seem too interesting to me - I never claimed particular originality, a lot of fallacies blend into each other, and the which-fallacy-is-which game isn't too exciting anyway - but for the record I don't think it is. Poisoning the well is a presentation of two different facts, such as "Martin Luther King was a plagiarist...oh, by the way, what do you think of Martin Luther King's civil rights policies?" It may have no relationship to categories, and it's usually something someone else does to you as a conscious rhetorical trick. Noncentral fallacy is presenting a single fact, but using category information to frame it in a misleading way - and it's often something people do to themselves. The above plagiarism example of poisoning the well is not noncentral fallacy. If you think this essay is about bog-standard poisoning the well, then either there is an alternative meaning to poisoning the well I'm not familiar with, or you are missing the point.