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->''"If a crazy serial killer who believes he is surrounded by Teletubbies argues that if you drop a ball, it'll fall to the ground, because gravity will pull the ball towards the Earth, is he wrong? Do the arguments become less valid because you think there's something wrong with the person behind the arguments? Will the ball start falling upwards from now on?"''
-->-- DeadpanSnarker Dendrophilian of Website/YouTube

Refuting an argument by attacking some aspect of the person making it, rather than addressing the content of the argument itself. It can consist of an attack on the person making the argument; the source of their information; their circumstances; their previous position; or a discrepancy between their actions and their argument.

Ad hominem is very often mistakenly claimed in cases where an argument's opponent attacks its proponent ''in addition to presenting a valid counterargument''. "You're stupid, therefore your argument is invalid" is an ''ad hominem''; "your argument is invalid, therefore you're stupid" (or "Your argument is invalid ''and'' you're stupid") is not. Similarly, some people seem to think that Ad Hominem is necessarily abusive, which it isn't. "You've used the '[[FourTermsFallacy Four Terms]]' fallacy, you stupid idiot, therefore you're using faulty logic" is not Ad Hominem (although it might be FallacyFallacy if done badly). "Mike has clearly put a lot of thought into whether we should buy a pool, but he ''is'' a convicted felon" is.

Types of Ad Hominem:
* Direct: An attack directly on the person making the argument themselves.
* Circumstantial: The attack is on the circumstances surrounding the person making the argument.
* Poisoning the Well: A usually-preemptive attack on a source of information is intended to call into question ''everything'' it says.
* Tu Quoque ("You, too!"): The attack is that the [[StrawHypocrite person making the argument does the same thing they're arguing against themselves]], or that they, at some previous time, held a different opinion.

Closely related to Ad Hominem:
* Style Over Substance: The attack is not on the ''person'' making the argument, but on ''the manner in which they presented it''.

A good discussion of the ''ad hominem'' fallacy on the Internet may be found [[http://archive.today/UBJGx on the website of one Stephen Bond]]. See also DontShootTheMessage, HitlerAteSugar, NoYou, HypocriteHasAPoint.

[[folder:Direct Ad Hominem]]
!!'''Direct ad hominem'''
The attack is made directly on the person making the argument. Here's a standard hypothetical example:

-->'''UsefulNotes/AdolfHitler:''' This is an irresponsible fiscal policy because the budget deficit is too great.\\
'''Politician:''' I won't listen to you! [[GodwinsLaw You're Hitler]]!

While Hitler certainly wasn't a nice person, that in itself is unrelated to [[HitlerAteSugar the logical validity of any arguments he makes]]. This extends to a degree in situations where the ad hominem attack itself is ''related'' to the argument; if the supposition comes from a source that is known for fallibility or may have a reason to be biased, it should be treated with healthy skepticism, but not assumed to be false.

-->The [[LuridTalesOfDoom Weekly World News]] says that UsefulNotes/GeorgeWashington was the first president of the United States.

It would be quite logically sound to say "Why should we take their word for it? They're unreliable and biased!" It is not sound, however, to say that the above statement ''must'' be false, because despite the fact that the Weekly World News was noted for being full of made-up stories, UsefulNotes/GeorgeWashington ''was'' the first President of the United States-and this was common knowledge long before ''Weekly World News'' existed.

* Most people can recognize a simplistic ad hominem attack as humorous, but that didn't stop [=DirecTv=] from flipping out at a spot by Time Warner asserting that "[[http://www.youtube.com/watch?v=anKkX1wvgBw DirecTv hates puppies]]"
* The white nationalist community likes to allege that the term "racism" was coined by UsefulNotes/LeonTrotsky, [[InsaneTrollLogic and therefore all opposition to racism is a communist plot]].
* Read an article about social justice and related topics. Now read the comments about how often the ''entire'' argument is somehow rendered meaningless because of who said it. If you get in any debate about social justice, expect to see this thrown around a ''lot'' from both sides.

!!!Looks like this fallacy but is not:
* When the rebuttal is insulting but relevant and true: "You can't be a member of UsefulNotes/{{Mensa}} as you claim, because your IQ tests indicate that your IQ is 70".
* When an insult is present but is [[http://community.livejournal.com/wrongworddammit/283991.html not used as a component of a logical argument]]. Simply saying "You are an idiot" is not polite, but unless there's a "therefore" step to a conclusion, it is not a fallacy. On the other hand, "you are an idiot, therefore your logic is fallacious" is.
* Attacking a person for having some character flaw that does not adversely affect or negate the things that he or she is famous for. Therefore, something like [[ItsNotSupposedToWinOscars "He's not the Pope!" or "He's not Jesus!"]] is not a valid comeback; at issue is not whether the person has a right to be famous, but whether he or she can be considered a good role model ''due'' to that fame (Pete Rose's gambling, Creator/MelGibson's alcoholism and racism).

[[folder:Circumstantial Ad Hominem]]
!!'''Circumstantial ad hominem'''
When the circumstances of the arguer are held to affect the truth of the argument. It's frequently rolled out against people who have any kind of motive for making their argument (the "he ''would'' say that, wouldn't he?" defense), often intended to imply that "he" is an incredibly selfish/malicious person for even looking at the idea with an open mind (or, alternatively, that his mind isn't as open as "he" claims it is). In reality, it's more unreasonable to expect someone to have ''no'' reason to hold their viewpoint; their vested interest does not automatically invalidate their criticism.

Impugning motives is a common form of this. A speaker resorting to impugning motives attacks the speaker's personal reasons for supporting a position rather than their arguments in favor of supporting the position. Of course, the underlying motives of a person making an argument do not affect the truth or validity of their argument. Furthermore, it's not necessary to impugn a speaker's actual motives - a person using this type of ad hominem often ascribes motives to their opponent and then impugns them.

-->'''Bob:''' "This bill will be expensive and will not work, therefore you should vote against it."\\
'''Alice:''' "Bob is employed by a company which stands to lose money from this bill, therefore Bob will lose money and perhaps his job if this bill passes. ''Of course'' he would oppose it."

* All instances of "What ''they'' don't want you to know..." have at least a tacit form of the impugning motives form of an ad hominem. For example, "What doctors don't want you to know..." tacitly assumes ''all'' physicians have a vested interest in keeping you from learning about some miracle cure and are willing to ignore their Hippocratic Oaths to do so. Even if this were true, which it is not, it would be up to the "Miracle Cure Salesman" to prove his or her AllNaturalSnakeOil actually works better than the standard science-based alternative.
** Expect an immediate case of SpecialPleading to follow.
* The common (something)-splaining rebuttal in social justice circles is intended to discredit a speaker simply because they come from a particular group which is held to be defending the status quo that they benefit from. This is usually tied to an inverse use, that simply living through something automatically means one has insight into it that is inaccessible to outsiders and should not be questioned by them.
* This commonly comes up in any discussion of police or the military overstepping their boundaries, especially in any highly-charged case. If an investigation turns up nothing, regardless of whatever internal investigations were done, there will be cries of "They just want to cover for each other and hush it up!" Of course, the FallacyFallacy also applies-it may indeed be true that there was a cover-up. Real life examples should probably be left to the reader's imagination.
** ''Series/TheDailyShow'' had a great example of one on their March 31st, 2014 episode. Chris Christie, governor of New Jersey as of the time of writing (April 2014), was embattled in a scandal regarding blocking a bridge out of spite. Governor Christie announced the result of an inquiry done by his own hand-picked legal team. The report exonerated Christie. Jon Stewart dismissed the report just on the grounds that it came from Christie's office. That is a clear case of this fallacy. However, it would be a case of the FallacyFallacy to say that Jon's ad hominem ''proves'' Governor Christie is in the clear, as it's certainly reasonable to be suspicious. Especially after it was later proved he was involved, though not in any legally binding fashion.
* Advertisers have a vested interest in convincing you their product is what you want. It is poor logic to dismiss a claim on the grounds that "They want to sell me something," which is not to say that in the real world that can't raise one's suspicion. There's a difference between deception and bad logic.

!!!Looks like this fallacy, but is not:
* If an individual is supposed to be in a position that ''requires'' them to be objective, such as a judge or a journalist, pointing out a conflict of interest is a valid argument ''against their claimed objectivity'', but does not, in itself, demonstrate any claim they have made is false.
* When used to argue that a person may deserve a higher degree of suspicion than others due to some relevant circumstance. For example, you can logically conclude that someone who's been accused of embezzlement is a bad person to hire for your bank, and it's obviously relevant when you're making a decision under uncertainty about who to hire.

[[folder:Poisoning the Well]]
!!'''Poisoning the Well'''
This fallacy can be one of two types, either discrediting the opponent before they even begin to make their argument, usually by a direct ad hominem against them - "And might I just remind the audience before Alice speaks that she is a convicted felon?" - or by calling the validity of their sources or standing into question after they have made their argument. More or less the converse of AppealToAuthority; here, the attempt is to make an audience reject a claim because of the speaker's alleged lack of authority.

-->"You'll find Bob talks about law an awful lot for a guy who got his degree from Eastern Iowa State University."

The attempt here is to preemptively discredit Bob's standing as a lawyer not on the basis of what he's actually saying, but on where he was schooled.

The most pernicious manifestation is where entire groups are potentially shut out of the discussion:

** Men can't talk about abortion because they don't get pregnant.[[note]]But they are born; fetuses are male as well as female.[[/note]]
** American whites can't talk about slavery because they never experienced it.[[note]]Jews (who are usually considered white) experienced an equally long amount of time as slaves in Babylon and various other places, making the antisemitism present in some black radical circles [[WeAreStrugglingTogether even more ridiculous]].[[/note]]
** Rich people who help poor people can't truly sympathize with whom they're helping, so they must be doing it for some selfish reason.[[note]]Rich people aren't incapable of altruism, or of the rational belief that a society free of poverty is best for everyone and demanded by justice. Some rich people used to be poor as well.[[/note]]

This seems like an example, but is actually a different problem of logic:

--> "You cited the Encyclopedia Britannica. A recent study found that Encyclopedia Britannica had 123 errors of fact -- in only 42 articles."

As a reply to "This fact is true because the Encyclopedia Britannica states as much," this has a sound logical basis; because the cited reason to believe the statement is the credibility of the encyclopedia, an attack on its credibility is relevant and therefore ''not'' poisoning the well. However, as a response to ''the fact itself'' it ''is'' a fallacy since the encyclopedia containing other errors does not mean that specific piece of information is an error: to be specific, it is a Hasty Generalization. These factual errors could be minor misspellings of titles that all occurred in one mistranslated article, for example.

* Most accusations of white knighting are intended to discredit the accused by making it seem as if they have a self-interested reason to hold their stated position. While this ''may'' be true, it does not make said position any less valid.
* ''Film/ReeferMadnessTheMusical'' features a propagandist who uses this when a parent objects to the propagandist's absurd story about marijuana abuse. He starts by using an AppealToWealth and AppealToAuthority to point out that William Randolph Hearst agrees with his position, then demands to know where the man matriculated. When the man doesn't know the word matriculate, the propagandist goes in for the kill and makes the man admit he never went to college. The propagandist then dismisses the man entirely. Later, he takes it a step further by claiming the man's views are "extreme" and "Un-American."

%%!!!Looks like this fallacy but is not:

[[folder:Tu Quoque]]
!!'''[[http://en.wikipedia.org/wiki/Tu_quoque Tu quoque]]''' ("[[AltumVidetur You, too!]]")
Another type of Ad Hominem, Tu Quoque refers to the attempt to deny an argument by asserting that the person presenting the argument either suffers from the same flaw (i.e. they do not practice what they preach) or has held an opposing view in the past. The fact that such a person is a {{hypocrite}} if he criticizes others for bearing the same flaw he does in his personal life [[HypocriteHasAPoint is actually not related to actual objective facts about said flaw or his line of reasoning in condemning that flaw]].

-->'''Bob:''' "Smoking and alcoholism are well-known as risks for cancer."\\
'''Alice:''' "But you yourself smoke and drink a lot! You're wrong!"

The fact that Bob is a smoker and drinker doesn't mean that he is wrong about the effects of those habits. Still confused? A better rebuttal would be to accept the premise that alcohol and smoking really are cancer risks, but then ask why Bob continues to do them. Perhaps Bob knows full well about the dangers of such addictions, but he may or may not be a hedonist with no sense of self-preservation, or it's just because he cannot or is yet to break from his very own addiction, hence why he continues to do it. Or because he is consciously or unconsciously suicidal, which makes his self-harm a logical consequence. Or he could know that he shouldn't be smoking, but [[WeakWilled not have the willpower to resist the temptation to do it]]. (Of course, if Bob mysteriously continues to survive and never even gets sick, Alice may have a point about his being wrong.)

Another example is how (former) drug addicts who have suffered for their drug usage can also be very well qualified in admonishing others to not get started in harmful, expensive, illegal, and addictive substances (sometimes even more so due to personal experience and physical proof of the damage incurred by the drug addiction). They may be challenged on this point only if they adopt a HolierThanThou attitude and [[BlatantLies act as if they were never addicted at all]], or make [[NeverMyFault self-serving excuses]] ("I was manipulated by TheAggressiveDrugDealer, while ''you'' made the stupid decision to do drugs yourself.").

-->'''Bob:''' "This bill will be expensive and will not work, therefore you should vote against it."\\
'''Alice:''' "But you supported the bill last month!"

Now, simply pointing out a contradiction in someone's arguments is not Ad Hominem Tu Quoque. A fallacy must be a component of a logical argument, and it is not an argument unless a conclusion is drawn from the observed contradiction. Therefore, Tu Quoque only applies when it is argued the opponent's argument ''is wrong because'' it contradicts a previous position they've held. Once again, [[SoundValidTrue his reasoning might be unsound, but that does not affect the truth value of his premises]]. Bob's new argument is not invalidated by any previous position he may have held.

This can be particularly irritating if used in combination with a Strawman version of a previous position: the final nail in this particular coffin is usually ArgumentumAdNauseam, demanding the opponent justify their current argument's alleged conflict with a position they never actually held, while refusing all attempts at clarification.

* This is a favorite tactic of politicians and political dissidents who want to discredit an opponent; they usually call it "flip-flopping" or "waffling" and use it to imply that the opponent can't make up their mind.
* A German politician once said "I don't care about the shit I said last week!"
* A common version used against complaints is for a debater to bring up a separate event which they feel their opponent ''should'' have had the same reaction to; the "Where were you when..." argument is always invalid. Whether the opponent should have been equally outraged at another event has no effect on whether their outrage at ''this'' event is valid.
** A good example of this was the controversy over ''VideoGame/ResidentEvil5's'' alleged racism. A common rebuttal was that those complaining about a white man shooting black people did not complain about the previous game where a white man was shooting Spanish people, so a) their complaints were not valid, or b) shooting black people was somehow considered "worse" than shooting Spaniards.
** This is closely tied to the Red Herring AppealToWorseProblems, since the thing bought up is often something held to be worse than the thing they are currently talking about.
* [[BeamMeUpScotty John Maynard Keynes's often-quoted response to such tactics]]:
-->When the facts change, I change my mind. What do you do, sir?
* Used in an episode of ''Series/{{Scrubs}}'', when Eliot railed at the "hypocrisy" of Dr. Cox advising someone to calm down for the sake of his blood pressure, or Dr. Kelso telling a patient to stop smoking. When she herself got a patient who was fainting due to being slightly less underweight than she was, she initially tried to build her own weight in concert with the patient, but eventually realized "This is about you, not me."
* "A strong leader is expected to maintain steadfast resolve in his opinion even if the environment changes or he gets new information. In any other context, that would be considered the first sign of a brain tumor."-Scott Adams
* During an Australia vs. England UsefulNotes/{{Cricket}} match, Mike Atherton edged the ball to wicket keeper Ian Healy, but was given "not out", prompting the following exchange:
-->'''Healy:''' You're a fucking cheat.\\
'''Atherton:''' When in Rome, dear boy...
* The ever-persistent "You criticize X, but you're using something provided by X!" argument.
* When fanfic writer pstibbons was called out for writing a ''Franchise/HarryPotter'' fanfic whose only purpose was to have Hermione torture and humiliate [[RonTheDeathEater Ron]], he cited an earlier work of his where Ron is brutally murdered by Harry, claiming that since people didn't raise a fuss back then, they are clearly sexist.[[note]]Several people did, in fact, complain about Ron's treatment in that fic as well, but since Ron's death at Harry's hand was merely referenced in a single off-hand sentence, compared to an entire fic devoted to it, it didn't draw nearly as much attention.[[/note]]
* UsefulNotes/RichardDawkins in ''The God Delusion'' illustrated a striking example used by a member of the Cult of John Frum, a real-world CargoCult. The cults have numerous forms, such as those that proclaim Frum is the King of America and that he will come in an apocalyptic cataclysm with deliverance and tons of material goods. A researcher asked a believer, "Isn't 19 years a long time to wait for John Frum?" The believer replied, "If the white man can wait two thousand years for Jesus Christ..."
* This was a favorite propaganda technique of the Soviet Union during the Cold War. In the West, it was nicknamed "whataboutism" since such arguments often began with the words "what about". In RussianHumour, this was parodied with the StockPhrase "and you lynch blacks" ("а у вас негров линчуют"), which was sarcastically used as a catch-all to dismiss criticism of the Soviet Union in situations where American race relations were not relevant to the issue.
* People facing ''ad hominem'' accusations of misogyny, racism or homophobia commonly respond with countercharges of [[DoesNotLikeMen misandry]], [[MalcolmXerox reverse racism]][[note]]with the [[BeggingTheQuestion dubious]] implication that racism has default and reverse states, as opposed to a single state that appears whenever someone denigrates a racial group other than their own[[/note]] and [[HetIsEw heterophobia]], respectively, thereby fighting fallacy with fallacy.

!!!Looks like this fallacy but is not:
* {{Doublethink}}. At first, ignoring the speaker's hypocrisy seems to mean accepting any contradictory actions he performs. However, accepting Tu Quoque as a fallacy does not mean accepting all {{Doublethink}} spewed out by hypocrites and abusers of ScrewTheRulesIMakeThem as logically valid. Tu Quoque is when the speaker's hypocrisy is used to discredit any objective real-world facts he says, but {{Doublethink}} means accepting all logically fallacious contradictions he says.
* About the earlier "You criticize X, but you're using something by X" argument: If this is used to discredit ''any'' facts he says, then it is wrong (for example, you support human rights but continue to use Apple products that you know were made through Chinese slave labor. That does not mean you are automatically wrong about your human rights opinions). If this is used to point out that the speaker's recommendations should not yet be trusted, then it isn't AHTQ. (For example, it is not a fallacy if you ask first why Luddites keep using computers instead of living without such things. If the conclusion is that "this hypocrite can't be trusted", then it can bring up a valid question. If this is used to mean "Luddites are completely wrong about everything", then it is AHTQ).
* When the value of the speaker's word is being considered in order to evaluate his statements as testimony. It is not fallacious for a court to consider the reliability of a witness doubtful if they find he has a history of committing perjury or has accepted money in exchange for his testimony; it is only fallacious if his testimony is ''discarded out of hand'' on this basis, regardless of what it actually is.
* When the speaker is arguing that the opponent is treating something as ''uniquely'' wrong, yet has done the same thing themselves. For example, if a boy is sent to his room for being the only person in his house to ever raid the biscuit tin, it would not be fallacious for him to point out that he did it because he saw his father doing it, therefore his punishment is based on a false premise.

[[folder:Style Over Substance]]
!!'''Style Over Substance'''
!!!Also called:
* [[Disney/{{Bambi}} If You Can't Say Something Nice...]]
* Appeal to Brevity
* [[MemeticMutation Too long; Didn't read]] ([=tl;dr=] or "teal deer")
* GrammarNazi

A closely-related fallacy to Ad Hominem, the "style over substance" fallacy is where the manner in which an argument is presented [[YouMakeMeSic is held to affect the validity of that argument.]]

A common version is to dismiss an entire argument if the person making it uses bad language or insults, or sounds "too angry" -- in essence, claiming that since their opponent cannot conduct themselves "politely," they obviously have nothing worthwhile to add to the discussion. Throwing someone out for breaking rules of conduct is not fallacious, but throwing their ''arguments'' out on this basis certainly is.

-> Alice: ''"No, Bob, it's fucked up that women at this job work the same hours for less pay and less opportunities. I've been here eight goddamn years and seen worse-qualified men get promoted above me. Like that brainless shit Andy, you know very well I have to do half his work for him and he gets all the credit. I prepared that presentation he got a bonus for!"''
-> Bob: ''"You're just angry. I don't see any reason to take this seriously."''

This is sometimes called a "tone" argument. When brought up on message boards, it's often called "tone trolling" if the post only complains of some other poster's "tone" without adding to a discussion. Since people are often passionate about things that affect them personally and ''cannot'' detach themselves from the associated feelings, this use of the fallacy is often summarised as "victory goes to whoever cares the least."

Another common variant is to disregard an argument presented in an allegedly incorrect manner; for example, because it is too long, too short, badly-spelled, badly punctuated, or uses poor grammar. Not making the effort to make a coherent, concise reply is certainly rude, but being rude is not the same as being wrong. This fallacy is quite common in internet discussions, and boils down to "You didn't present your argument the way I like, therefore it is wrong."

Note that saying "Your argument is presented poorly, therefore I will not read/listen to it," is ''not'' a logical fallacy, unless you also state that the argument they were making is false because of its poor presentation.

!!!Looks like this fallacy but is not:
* When the presentation is so unclear that it is genuinely impossible to follow the reasoning.
* When the errors are pointed out simply for the sake of pointing out the errors, rather than as evidence that the arguer is wrong. Though this is often referred to as "nitpicking" in debates and is generally frowned upon, since pointing out errors that have nothing to do with the opponent's central point achieves nothing.
* When the opponent is using a dishonest debating technique referred to as Proof by Verbosity or the Gish Gallop; firing so many ''weak'' points off that it is impossible to respond to them within the format of the debate (usually because they require detailed rebuttals or specialist knowledge), with the intention of declaring they have stumped their opponent if even one point is left unaddressed, and robbing them of any time to actually present their own arguments in a timed debate setting. In essence, the opponent may have nothing but mud to sell, but by piling it up so thick so quickly they hope to pass it off as rock solid. This comes [[http://en.wikipedia.org/wiki/Gish_Gallop#Debates from Duane Gish]], who used the tactic frequently.
* When the opponent complains of tone, but doesn't use this as an argument. For instance, they might find the way that the opponent presented it overly hostile, obnoxious, etc., while this isn't used as evidence of their argument being invalid. It would be best to carefully separate this out, however, so a tone argument isn't inferred.
-->''[[YourMom Yer mum]] 'ad all a them phalluses!''