Several of these have names in Latin, but I mostly ignored that and used English.
If anyone is bothered by my using “he” everywhere, note that “he” is the person arguing fallaciously.

Some other Web sites:

 
Ad Hominem (Argument To The Man): attacking the person instead of attacking his argument. For example, “Von Daniken’s books about ancient astronauts are worthless because he is a convicted forger and embezzler.” (Which is true, but that’s not why they’re worthless.) Another example is this syllogism, which alludes to Alan Turing’s homosexuality: Turing thinks machines think. Turing lies with men. Therefore, machines don’t think. (Note the equivocation in the use of the word “lies”.) A common form is an attack on sincerity. For example, “How can you argue for vegetarianism when you wear leather shoes ?” The two wrongs make a right fallacy is related. A variation (related to Argument By Generalization) is to attack a whole class of people. For example, “Evolutionary biology is a sinister tool of the materialistic, atheistic religion of Secular Humanism.” Similarly, one notorious net kook waved away a whole category of evidence by announcing “All the scientists were drunk.” Another variation is attack by innuendo: “Why don’t scientists tell us what they really know; are they afraid of public panic ?”  There may be a pretense that the attack isn’t happening: “In order to maintain a civil debate, I will not mention my opponent drinking problem.” Or “I don’t care if other people say you’re [opinionated/boring/overbearing].” Attacks don’t have to be strong or direct. You can merely show disrespect, or cut down his stature by saying that he seems to be sweating a lot, or that he has forgotten what he said last week. Some examples: “I used to think that way when I was your age.” You’re new here, aren’t you ?” “You weren’t breastfed as a child, were you ?” “What drives you to make such a statement?” “If you’d just listen.” “You seem very emotional.” (This last works well if you have been hogging the microphone, so that they have had to yell to be heard.)Sometimes the attack is on the other person’s intelligence. For example, “If you weren’t so stupid you would have no problem seeing my point of view.” Or, “Even you should understand my next point.”Oddly, the stupidity attack is sometimes reversed. For example, dismissing a comment with “Well, you’re just smarter than the rest of us.” (In Britain, that might be put as “too clever by half”.) This is Dismissal By Differentness. It is related toNot Invented Here and Changing The Subject.Ad Hominem is not fallacious if the attack goes to the credibility of the argument. For instance, the argument may depend on its presenter’s claim that he’s an expert. (That is, the Ad Hominem is undermining an Argument From Authority.) Trial judges allow this category of attacks.<
Needling:simply attempting to make the other person angry, without trying toaddress the argument at hand. Sometimes this is a delaying tactic.Needling is also Ad Hominem if you insultyour opponent. You may instead insult something the other personbelieves in (“Argumentum Ad YourMomium”), interrupt, clown to showdisrespect, be noisy, fail to pass over the microphone, and numerousother tricks. All of these work better if you are running things – forexample, if it is your radio show, and you can cut off the otherperson’s microphone. If the host or moderator is firmly on your side,that is almost as good as running the show yourself. It’s even betterif the debate is videotaped, and you are the person who will edit thevideo.If you wink at the audience, or in general clown in theirdirection, then we are shading over to Argument ByPersonal Charm.Usually, the best way to cope with insults is to show mildamusement, and remain polite. A humorous comeback will probably workbetter than an angry one.

    • Straw Man (Fallacy Of Extension):attacking an exaggerated or caricatured version of your opponent’sposition.For example, the claim that “evolution means a dog givingbirth to a cat.”Another example: “Senator Jones says that we should not fundthe attack submarine program. I disagree entirely. I can’t understandwhy he wants to leave us defenseless like that.”On the Internet, it is common to exaggerate the opponent’s positionso that a comparison can be made between the opponent and Hitler.
    • Inflation Of Conflict:arguing that scholars debate a certain point. Therefore, they mustknow nothing, and their entire field of knowledge is “incrisis” or does not properly exist at all.For example, two historians debated whether Hitler killed fivemillion Jews or six million Jews. A Holocaust denier argued that thisdisagreement made his claim credible, even though his deathcount is three to ten times smaller than the known minimum.Similarly, in “The Mythology of Modern Dating Methods”(John Woodmorappe, 1999) we find on page 42 that two scientists”cannot agree” about which one of two geological dates is”real” and which one is “spurious”. Woodmorappefails to mention that the two dates differ by less than one percent.
    • Argument From Adverse Consequences (Appeal To Fear, Scare Tactics):saying an opponent must be wrong, because if he is right, thenbad things would ensue. For example: God must exist, becausea godless society would be lawless and dangerous. Or: thedefendant in a murder trial must be found guilty, becauseotherwise husbands will be encouraged to murder their wives.Wishful thinking is closely related. “My home in Florida isone foot above sea level. Therefore I am certain thatglobal warmingwill not make the oceans rise by fifteen feet.” Of course, wishfulthinking can also be about positive consequences, such as winning thelottery, or eliminating poverty and crime.
    • Special Pleading (Stacking The Deck):using the arguments that support your position, but ignoring orsomehow disallowing the arguments against.Uri Geller used special pleading when he claimed that the presenceof unbelievers (such as stage magicians) made him unable todemonstrate his psychic powers.
    • Excluded Middle (False Dichotomy, Faulty Dilemma, Bifurcation):assuming there are only two alternatives when in fact there are more.For example, assuming Atheism is the only alternative toFundamentalism, or being a traitor is the only alternative to being aloud patriot.
    • Short Term Versus Long Term:this is a particular case of the ExcludedMiddle. For example, “We must deal with crime on the streetsbefore improving the schools.” (But why can’t we do some ofboth ?) Similarly, “We should take the scientific research budgetand use it to feed starving children.”
    • Burden Of Proof:the claim that whatever has not yet been proved false must be true(or vice versa). Essentially the arguer claims that he should win bydefault if his opponent can’t make a strong enough case.There may be three problems here. First, the arguer claims priority,but can he back up that claim ? Second, he is impatient withambiguity, and wants a final answer right away. And third,”absence of evidence is not evidence of absence.”
    • Argument By Question:asking your opponent a question which does not have a snappyanswer. (Or anyway, no snappy answer that the audience has thebackground to understand.) Your opponent has a choice: he can lookweak or he can look long-winded. For example, “How canscientists expect us to believe that anything as complex as a singleliving cell could have arisen as a result of random naturalprocesses ?”Actually, pretty well any question has this effect to some extent.It usually takes longer to answer a question than ask it.Variants are the rhetoricalquestion, and the loaded question, such as “Have youstopped beating your wife ?”
    • Argument by Rhetorical Question:asking a question in a way that leads to a particular answer. Forexample, “When are we going to give the old folks of this countrythe pension they deserve ?” The speaker is leading the audience tothe answer “Right now.” Alternatively, he could have said”When will we be able to afford a major increase in old agepensions?” In that case, the answer he is aiming at is almostcertainly not “Right now.”
    • Fallacy Of The General Rule:assuming that something true in general is true in every possiblecase. For example, “All chairs have four legs.” Except thatrocking chairs don’t have any legs, and what is a one-legged”shooting stick” if it isn’t a chair ?Similarly, there are times when certain laws should be broken. Forexample, ambulances are allowed to break speed laws.
    • Reductive Fallacy (Oversimplification):over-simplifying. As Einstein said, everything should be made assimple as possible, but no simpler. Political slogans such as”Taxation is theft” fall in this category.
    • Genetic Fallacy (Fallacy of Origins, Fallacy of Virtue):if an argument or arguer has some particular origin, the argument mustbe right (or wrong). The idea is that things from that origin, or thatsocial class, have virtue or lack virtue. (Being poor or being richmay be held out as being virtuous.) Therefore, the actual details ofthe argument can be overlooked, since correctness can be decidedwithout any need to listen or think.
    • Psychogenetic Fallacy:if you learn the psychological reason why your opponent likes an argument,then he’s biased, so his argument must be wrong.
    • Argument Of The Beard:assuming that two ends of a spectrum are the same, since one cantravel along the spectrum in very small steps. The name comes fromthe idea that being clean-shaven must be the same as having a bigbeard, since in-between beards exist.Similarly, all piles of stones are small, since if you add onestone to a small pile of stones it remains small.However, the existence of pink should not undermine the distinctionbetween white and red.
    • Argument From Age (Wisdom of the Ancients):snobbery that very old (or very young) arguments are superior. Thisis a variation of the Genetic Fallacy, but hasthe psychological appeal of seniority and tradition (or innovation).Products labelled “New ! Improved !” are appealing to abelief that innovation is of value for such products. It’s sometimestrue. And then there’s cans of “Old Fashioned Baked Beans”.
    • Not Invented Here:ideas from elsewhere are made unwelcome. “This Is The Way We’veAlways Done It.”This fallacy is a variant of the Argument FromAge. It gets a psychological boost from feelings that local waysare superior, or that local identity is worth any cost, or thatinnovations will upset matters.An example of this is the common assertion that America has”the best health care system in the world”, an idea thatthis 2007NewYork Times editorial refuted.People who use the Not Invented Here argument are sometimes accusedof being stick-in-the-mud’s.Conversely, foreign and “imported” things may be held outas superior.
    • Argument By Dismissal:an idea is rejected without saying why.Dismissals usually have overtones. For example, “If you don’tlike it, leave the country” implies that your cause is hopeless,or that you are unpatriotic, or that your ideasare foreign, or maybe all three. “If you don’tlike it, live in a Communist country” addsan emotive element.
    • Argument To The Future:arguing that evidence will someday be discovered which will (then)support your point.
    • Poisoning The Wells:discrediting the sources used by your opponent. This is a variation ofAd Hominem.
    • Argument By Emotive Language (Appeal To The People):using emotionally loaded words to sway the audience’s sentimentsinstead of their minds. Many emotions can be useful: anger, spite,envy, condescension, and so on.For example, argument by condescension: “Support the ERA ?Sure, when the women start paying for the drinks! Hah! Hah!”Americans who don’t like the Canadian medical system have referredto it as “socialist”, but I’m not quite sure if this isintended to mean “foreign”, or “expensive”, orsimply guilty by association.Cliche Thinking and Argument By Slogan are useful adjuncts,particularly if you can get the audience to chant the slogan. Peoplewho rely on this argument may seed the audience with supporters or”shills”, who laugh, applaud or chant at propermoments. This is the live-audience equivalent of adding a laugh trackor music track. Now that many venues have video equipment, somespeakers give part of their speech by playing a prepared video. Thesevideos are an opportunity to show a supportive audience, use emotionalmusic, show emotionally charged images, and the like. The idea is old:there used to be professional cheering sections. (Monsieur Zig-Zag,pictured on the cigarette rolling papers, acquired his fame byapplauding for money at the Paris Opera.)If the emotion in question isn’t harsh, ArgumentBy Poetic Language helps the effect. Flattering the audiencedoesn’t hurt either.
    • Argument By Personal Charm:getting the audience to cut you slack. Example: Ronald Reagan. Ithelps if you have an opponent with much less personal charm.Charm may create trust, or the desire to “join the winningteam”, or the desire to please the speaker. This last is greatestif the audience feels sex appeal.Reportedly George W. Bush lost a debate when he was young, and saidlater that he would never be “out-bubba’d” again.
    • Appeal To Pity (Appeal to Sympathy, The Galileo Argument):“I did not murder my mother and father with an axe ! Please don’tfind me guilty; I’m suffering enough through being an orphan.”Some authors want you to know they’re suffering for their beliefs.For example, “Scientists scoffed at Copernicus and Galileo; theylaughed at Edison, Tesla and Marconi; they won’t give my ideas a fairhearing either. But time will be the judge. I can wait; I ampatient; sooner or later science will be forced to admit that allmatter is built, not of atoms, but of tiny capsules of TIME.”There is a strange variant which shows up on Usenet. Somebodyrefuses to answer questions about their claims, on the grounds thatthe asker is mean and has hurt their feelings. Or, that the questionis personal.
    • Appeal To Force:threats, or even violence. On the Net, the usual threat is of alawsuit. The traditional religious threat is that one will burn inHell. However, history is full of instances where expressing anunpopular idea could you get you beaten up on the spot, or worse.”The clinching proof of my reasoning is that Iwill cut anyone who argues further into dogmeat.”– Attributed to Sir Geoffery de Tourneville, ca 1350 A.D.
    • Argument By Vehemence:being loud. Trial lawyers are taught this rule:If you have the facts, pound on the facts.If you have the law, pound on the law.If you don’t have either, pound on the table.The above rule paints vehemence as an act of desperation. But it canalso be a way to seize control of the agenda, use up the opponent’stime, or just intimidate the easily cowed. And it’s not necessarilyaimed at winning the day. A tantrum or a fit is also a way to get areputation, so that in the future, no one will mess with you.This is related to putting a post in UPPERCASE, aka SHOUTING.Depending on what you’re loud about, this may also bean Appeal To Force, ArgumentBy Emotive Language, Needling,or Changing The Subject.
    • Begging The Question (Assuming The Answer, Tautology):reasoning in a circle. The thing to be proved is used as one of yourassumptions. For example: “We must have a death penalty todiscourage violent crime”. (This assumes it discourages crime.)Or, “The stock market fell because of a technicaladjustment.” (But is an “adjustment” just a stockmarket fall ?)
    • Stolen Concept:using what you are trying to disprove. That is, requiring the truth ofsomething for your proof that it is false. For example, using scienceto show that science is wrong. Or, arguing that you do not exist, whenyour existence is clearly required for you to be making the argument.This is a relative of Begging The Question,except that the circularity there is in what you are trying to prove,instead of what you are trying to disprove.It is also a relative of Reductio Ad Absurdum,where you temporarily assume the truth of something.
    • Argument From Authority:the claim that the speaker is an expert, and so should be trusted.There are degrees and areas of expertise. The speaker is actuallyclaiming to be more expert, in the relevant subject area, thananyone else in the room. There is also an implied claim that expertisein the area is worth having. For example, claiming expertise insomething hopelessly quack(like iridology)is actually an admission that the speaker is gullible.
    • Argument From False Authority:a strange variation on Argument From Authority.For example, the TV commercial which starts “I’m not a doctor,but I play one on TV.” Just what are we supposed to conclude ?
    • Appeal To Anonymous Authority:an Appeal To Authority is made, but theauthority is not named. For example, “Experts agree that..”, “scientists say ..” or even “they say..”. This makes the information impossible to verify, and bringsup the very real possibility that the arguer himself doesn’t know whothe experts are. In that case, he may just be spreading a rumor.The situation is even worse if the arguer admits it’s a rumor.
    • Appeal To Authority:“Albert Einstein was extremely impressed with this theory.”(But a statement made by someone long-dead could be out of date. Orperhaps Einstein was just being polite. Or perhaps he made hisstatement in some specific context. And so on.)To justify an appeal, the arguer should at least present an exactquote. It’s more convincing if the quote contains context, and if thearguer can say where the quote comes from.A variation is to appeal to unnamedauthorities .There was a New Yorker cartoon, showing a doctor and patient. Thedoctor was saying: “Conventional medicine has no treatment foryour condition. Luckily for you, I’m a quack.” So the joke wasthat the doctor boasted of his lack of authority.
    • Appeal To False Authority:a variation onAppeal To Authority, but theAuthorityis outside his area of expertise.For example, “Famous physicist John Taylor studied Uri Geller extensively and found noevidence of trickery or fraud in his feats.” Taylor was notqualified to detect trickery or fraud of the kind used by stagemagicians. Taylor later admitted Geller had tricked him, but heapparently had not figured out how.A variation is to appeal to a non-existent authority. For example,someone reading an article by Creationist Dmitri Kuznetsov tried tolook up the referenced articles. Some of the articles turned out to bein non-existent journals.Another variation is to misquotea real authority. There are several kinds of misquotation. A quotecan be inexact or have been edited. It can be taken out ofcontext. (Chevy Chase: “Yes, I said that, but I was singing asong written by someone else at the time.”) The quote can beseparate quotes which the arguer glued together. Or, bits might havegone missing. For example, it’s easy to prove that Mick Jagger is anassassin. In “Sympathy For The Devil” he sang: “Ishouted out, who killed the Kennedys, When after all, it was …me.”
    • Statement Of Conversion:the speaker says “I used to believe in X”.This is simply a weak form of asserting expertise. The speaker isimplying that he has learned about the subject, and now that he isbetter informed, he has rejected X. So perhaps he is now anauthority, and this is an implied Argument FromAuthority.A more irritating version of this is “I used to think that waywhen I was your age.” The speaker hasn’t said what is wrong withyour argument: he is merely claiming that his age has made him anexpert.”X” has not actually been countered unless there isagreement that the speaker has that expertise. In general, any baldclaim always has to be buttressed.For example, there are a number of Creationist authors who say they”used to be evolutionists”, but the scientists who haverated their books haven’t noticed any expertise about evolution.
    • Bad Analogy:claiming that two situations are highly similar, when they aren’t.For example, “The solar system reminds me of an atom, withplanets orbiting the sun like electrons orbiting the nucleus. We knowthat electrons can jump from orbit to orbit; so we must look toancient records for sightings of planets jumping from orbit to orbitalso.”Or, “Minds, like rivers, can be broad. The broader the river,the shallower it is. Therefore, the broader the mind, the shallower itis.”Or, “We have pure food and drug laws; why can’t we have lawsto keep movie-makers from giving us filth ?”
    • Extended Analogy:the claim that two things, both analogous to a third thing, aretherefore analogous to each other. For example, this debate:”I believe it is always wrong to oppose the law by breakingit.””Such a position is odious: it implies that you would nothave supported Martin Luther King.””Are you saying that cryptography legislation is as importantas the struggle for Black liberation ? How dare you !”A person who advocates a particular position (say, about guncontrol) may be told that Hitler believed the same thing. The clearimplication is that the position is somehow tainted. But Hitler alsobelieved that window drapes should go all the way to the floor. Doesthat mean people with such drapes are monsters ?
    • Argument From Spurious Similarity:this is a relative of Bad Analogy. It issuggested that some resemblance is proof of a relationship. There isa WW II story about a British lady who was trained in spotting Germanairplanes. She made a report about a certain very important type ofplane. While being quizzed, she explained that she hadn’t been sure,herself, until she noticed that it had a little man in the cockpit,just like the little model airplane at the training class.
    • Reifying:an abstract thing is talked about as if it were concrete. (A possiblyBad Analogy is being made between concept andreality.) For example, “Nature abhors a vacuum.”
    • False Cause:assuming that because two things happened, the first one caused thesecond one. (Sequence is not causation.) For example, “Beforewomen got the vote, there were no nuclear weapons.” Or,”Every time my brother Bill accompanies me to Fenway Park, theRed Sox are sure to lose.”Essentially, these are arguments that the sun goes down becausewe’ve turned on the street lights.
    • Confusing Correlation And Causation:earthquakes in the Andes were correlated with the closest approachesof the planet Uranus. Therefore, Uranus must have caused them. (ButJupiter is nearer than Uranus, and more massive too.)When sales of hot chocolate go up, street crime drops. Does thiscorrelation mean that hot chocolate prevents crime ? No, it means thatfewer people are on the streets when the weather is cold.The bigger a child’s shoe size, the better the child’s handwriting.Does having big feet make it easier to write ? No, it means the childis older.
    • Causal Reductionism (Complex Cause):trying to use one cause to explain something, when in fact it hadseveral causes. For example, “The accident was caused by the taxiparking in the street.” (But other drivers went around thetaxi. Only the drunk driver hit the taxi.)
    • Cliche Thinking:using as evidence a well-known wise saying, as if that is proven,or as if it has no exceptions.
    • Exception That Proves The Rule:a specific example of Cliche Thinking. Thisis used when a rule has been asserted, and someone points out the ruledoesn’t always work. The cliche rebuttal is that this is “theexception that proves the rule”. Many people think that thiscliche somehow allows you to ignore the exception, and continue usingthe rule.In fact, the cliche originally did no such thing. There are two standardexplanations for the original meaning.The first is that the word “prove” meanttest. That is why the military takes its equipment to aProving Ground to test it. So, the cliche originally said thatan exception tests a rule. That is, if you find an exception to arule, the cliche is saying that the rule is being tested, and perhapsthe rule will need to be discarded.The second explanation is that the stating of an exception to arule, proves that the rule exists. For example, suppose it wasannounced that “Over the holiday weekend, students do not need tobe in the dorms by midnight”. This announcement implies thatnormally students do have to be in by midnight. Here is a discussionof that explanation.In either case, the cliche is not about waving away objections.
    • Appeal To Widespread Belief (Bandwagon Argument, Peer Pressure, Appeal to Common Practice):the claim, as evidence for an idea, that many people believe it, orused to believe it, or do it.If the discussion is about social conventions, such as “goodmanners”, then this is a reasonable line of argument.However, in the 1800’s there was a widespread belief thatbloodletting cured sickness. All of these people were not just wrong,but horribly wrong, because in fact it made people sicker. Clearly,the popularity of an idea is no guarantee that it’s right.Similarly, a common justification for bribery is that”Everybody does it”. And in the past, this was ajustification for slavery.
    • Fallacy Of Composition:assuming that a whole has the same simplicity as its constituentparts. In fact, a great deal of science is the study of emergentproperties. For example, if you put a drop of oil on water, thereare interesting optical effects. But the effect comes from theoil/water system: it does not come just from the oil or just from thewater.Another example: “A car makes less pollution than abus. Therefore, cars are less of a pollution problem than buses.”Another example: “Atoms are colorless. Cats are made of atoms,so cats are colorless.”
    • Fallacy Of Division:assuming that what is true of the whole is true of each constituentpart. For example, human beings are made of atoms, and human beingsare conscious, so atoms must be conscious.
    • Complex Question (Tying):unrelated points are treated as if they should be accepted orrejected together. In fact, each point should be accepted or rejectedon its own merits.For example, “Do you support freedom and the right to beararms ?”
    • Slippery Slope Fallacy (Camel’s Nose)there is an old saying about how if you allow a camel to poke hisnose into the tent, soon the whole camel will follow.The fallacy here is the assumption that something is wrong becauseit is right next to something that is wrong. Or, it is wrong becauseit could slide towards something that is wrong.For example, “Allowing abortion in the first week of pregnancywould lead to allowing it in the ninth month.” Or, “If welegalize marijuana, then more people will try heroin.” Or,”If I make an exception for you then I’ll have to make anexception for everyone.”
    • Argument By Pigheadedness (Doggedness):refusing to accept something after everyone else thinks it iswell enough proved. For example, there are still Flat Earthers.
    • Appeal To Coincidence:asserting that some fact is due to chance. For example, the arguerhas had a dozen traffic accidents in six months, yet he insists theyweren’t his fault. This may be Argument ByPigheadedness. But on the other hand, coincidences do happen, sothis argument is not always fallacious.
    • Argument By Repetition (Argument Ad Nauseam):if you say something often enough, some people will begin to believeit. There are some net.kooks who keeping reposting the same articles toUsenet, presumably in hopes it will have that effect.
    • Argument By Half Truth (Suppressed Evidence):this is hard to detect, of course. You have to ask questions. Forexample, an amazingly accurate “prophecy” of theassassination attempt on President Reagan was shown on TV. But was thetape recorded before or after the event ? Many stations did not askthis question. (It was recorded afterwards.)A book on “sea mysteries” or the “BermudaTriangle” might tell us that the yacht Connemara IV was founddrifting crewless, southeast of Bermuda, on September 26, 1955. Noneof these books mention that the yacht had been directly in the path ofHurricane Iona, with 180 mph winds and 40-foot waves.
    • Argument By Selective Observation:also called cherry picking, the enumeration of favorablecircumstances, or as the philosopher Francis Bacon described it,counting the hits and forgetting the misses. For example, a stateboasts of the Presidents it has produced, but is silent about itsserial killers. Or, the claim “Technology bringshappiness”. (Now, there’s something with hits and misses.)Casinos encourage this human tendency. There are bells and whistlesto announce slot machine jackpots, but losing happens silently. Thismakes it much easier to think that the odds of winning are good.
    • Argument By Selective Reading:making it seem as if the weakest of an opponent’s arguments was thebest he had. Suppose the opponent gave a strong argument X and also aweaker argument Y. Simply rebut Y and then say the opponent has madea weak case.This is a relative of Argument By SelectiveObservation, in that the arguer overlooks arguments that he doesnot like. It is also related to Straw Man (Fallacy OfExtension), in that the opponent’s argument is not being fairlyrepresented.
    • Argument By Generalization:drawing a broad conclusion from a small number of perhapsunrepresentative cases. (The cases may be unrepresentative because ofSelective Observation.) For example,”They say 1 out of every 5 people is Chinese. How is thispossible ? I know hundreds of people, and none of them isChinese.” So, by generalization, there aren’t any Chineseanywhere. This is connected to the Fallacy OfThe General Rule.Similarly, “Because we allow terminally ill patients to useheroin, we should allow everyone to use heroin.”It is also possible to under-generalize. For example,”A man who had killed both of his grandmothers declared himselfrehabilitated, on the grounds that he could not conceivably repeat hisoffense in the absence of any further grandmothers.”– “Ports Of Call” by Jack Vance
    • Argument From Small Numbers:“I’ve thrown three sevens in a row. Tonight I can’t lose.”This is Argument By Generalization, but itassumes that small numbers are the same as big numbers. (Three sevensis actually a common occurrence. Thirty three sevens is not.)Or: “After treatment with the drug, one-third of the mice werecured, one-third died, and the third mouse escaped.” Does this meanthat if we treated a thousand mice, 333 would be cured ? Well, no.
    • Misunderstanding The Nature Of Statistics (Innumeracy):President Dwight Eisenhower expressed astonishment and alarm ondiscovering that fully half of all Americans had below averageintelligence. Similarly, some people get fearful when they learn thattheir doctor wasn’t in the top half of his class. (But that’s half ofthem.)”Statistics show that of those who contract the habit ofeating, very few survive.” — Wallace Irwin.Very few people seem to understand “regression to themean”. This is the idea that things tend to go back to normal.If you feel normal today, does it really mean that the headache cureyou took yesterday performed wonders ? Or is it just that yourheadaches are always gone the next day ?Journalists are notoriously bad at reporting risks. For example, in1995 it was loudly reported that a class of contraceptive pills woulddouble the chance of dangerous blood clots. The news stories mostlydid not mention that “doubling” the risk only increased itby one person in 7,000. The “cell phones cause brain cancer”reports are even sillier, with the supposed increase in risk being atmost one or two cancers per 100,000 people per year. So, if thefearmongers are right, your cellphone has increased your risk from”who cares” to “who cares”.
    • Inconsistency:for example, the declining life expectancy in the former Soviet Unionis due to the failures of communism. But, the quite high infantmortality rate in the United States is not a failure of capitalism.This is related to Internal Contradiction.
    • Non Sequitur:something that just does not follow. For example, “Tens of thousandsof Americans have seen lights in the night sky which they could notidentify. The existence of life on other planets is fast becomingcertainty !”Another example: arguing at length that your religion is of greathelp to many people. Then, concluding that the teachings of yourreligion are undoubtably true.Or: “Bill lives in a large building, so his apartment must belarge.”
    • Meaningless Questions:irresistible forces meeting immovable objects, and the like.
    • Argument By Poetic Language:if it sounds good, it must be right. Songs often use this effect tocreate a sort of credibility – for example, “Don’t Fear TheReaper” by Blue Oyster Cult. Politically oriented songs should betaken with a grain of salt, precisely because they sound good.
    • Argument By Slogan:if it’s short, and connects to an argument, it must be anargument. (But slogans risk the ReductiveFallacy.)Being short, a slogan increases the effectiveness of Argument By Repetition. It also helps Argument By Emotive Language (Appeal To ThePeople), since emotional appeals need to be punchy. (Also, thegallery can chant a short slogan.) Using an old slogan is Cliche Thinking.
    • Argument By Prestigious Jargon:using big complicated words so that you will seem to be an expert.Why do people use “utilize” when they could utilize”use” ?For example, crackpots used to claim they had a Unified FieldTheory (after Einstein). Then the word Quantum was popular. Lately itseems to be Zero Point Fields.
    • Argument By Gibberish (Bafflement):this is the extreme version of Argument ByPrestigious Jargon. An invented vocabulary helps the effect, andsome net.kooks use lots of CAPitaLIZation. However, perfectly ordinarywords can be used to baffle. For example, “Omniscience is greaterthan omnipotence, and the difference is two. Omnipotence plus twoequals omniscience. META = 2.” [From R. Buckminster Fuller’sNo More Secondhand God.]Gibberish may come from people who can’t find meaning in technicaljargon, so they think they should copy style instead of meaning. Itcan also be a “snow job”, AKA “baffle them withBS”, by someone actually familiar with the jargon. Or it could beArgument By Poetic Language.An example of poetic gibberish: “Each autonomous individualemerges holographically within egoless ontological consciousness as anon-dimensional geometric point within the transcendental thought-wavematrix.”
    • Equivocation:using a word to mean one thing, and then later using it to meansomething different. For example, sometimes “Free software”costs nothing, and sometimes it is without restrictions. Some examples:”The sign said ‘fine for parking here’, and since it wasfine, I parked there.”All trees have bark.All dogs bark.Therefore, all dogs are trees.”Consider that two wrongs never make a right, but that threelefts do.”- “Deteriorata”, National Lampoon
    • Euphemism:the use of words that sound better. The lab rat wasn’t killed, it wassacrificed. Mass murder wasn’t genocide, it was ethniccleansing. The death of innocent bystanders is collateraldamage. Microsoft doesn’t find bugs, or problems, or securityvulnerabilities: they just discover an issue with a piece ofsoftware.This is related to Argument By EmotiveLanguage, since the effect is to make a concept emotionallypalatable.
    • Weasel Wording:this is very much like Euphemism, except thatthe word changes are done to claim a new, different concept ratherthan soften the old concept. For example, an American President maynot legally conduct a war without a declaration of Congress. So,various Presidents have conducted “police actions”,”armed incursions”, “protective reaction strikes,””pacification,” “safeguarding American interests,”and a wide variety of “operations”. Similarly, WarDepartments have become Departments of Defense, and untested medicineshave become alternative medicines. The book “1984” has someparticularly good examples.
    • Error Of Fact:for example, “No one knows how old the Pyramids of Egyptare.” (Except, of course, for the historians who’ve read recordsand letters written by the ancient Egyptians themselves.)Typically, the presence of one error means that there are othererrors to be uncovered.
    • Argument From Personal Astonishment:Errors of Fact caused by stating offhand opinionsas proven facts. (The speaker’s thought process being “I don’tsee how this is possible, so it isn’t.”) An example fromCreationism is givenhere.This isn’t lying, quite. It just seems that wayto people who know more about the subject than the speaker does.
    • Lies:intentional Errors of Fact. In some contexts this is called bluffing.If the speaker thinks that lying serves a moral end, this would bea Pious Fraud.
    • Contrarian Argument:in science, espousing some thing that the speaker knows is generallyill-regarded, or even generally held to be disproven. For example,claiming that HIV is not the cause of AIDS, or claiming thathomeopathic remedies are not just placebos.In politics, the phrase may be used more broadly, to mean espousingsome position that the establishment or opposition party does nothold.This is sometimes done to make people think, and sometimes itis needling, or perhaps it supports anexternal agenda. But it can also be done just to oppose conformity, oras a pose or style choice: to be a “maverick” or lightningrod. Or, perhaps just for the ego of standing alone:”It is not enough to succeed. Friends must be seen to havefailed.”– Truman Capote”If you want to prove yourself a brilliant scientist, youdon’t always agree with the consensus. You show you’re right andeveryone else is wrong.”– Daniel Kirk-Davidoff discussing Richard LindzenCalling someone contrarian risks thePsychogenetic Fallacy. People who are annoyingare not necessarily wrong. On the other hand, if the position isill-regarded for a reason, then defending it may be uphill.Trolling is Contrarian Argument done to get a reaction. Trollingon the Internet often involves pretense.
    • Hypothesis Contrary To Fact:arguing from something that might have happened, but didn’t.
    • Internal Contradiction:saying two contradictory things in the same argument. For example,claiming thatArchaeopteryx is a dinosaur with hoaxed feathers, and also sayingin the same book that it is a “true bird”. Or anotherauthor who said on page 59, “Sir Arthur Conan Doyle writes in hisautobiography that he never saw a ghost.” But on page 200 we find”Sir Arthur’s first encounter with a ghost came when he was 25,surgeon of a whaling ship in the Arctic..”This is much like saying “I never borrowed his car, and italready had that dent when I got it.”This is related to Inconsistency.
    • Changing The Subject (Digression, Red Herring, Misdirection, False Emphasis):this is sometimes used to avoid having to defend a claim, or to avoidmaking good on a promise. In general, there is something you are notsupposed to notice.For example, I got a bill which had a big announcement about howsome tax had gone up by 5%, and the costs would have to be passed onto me. But a quick calculation showed that the increased tax was onlycosting me a dime, while a different part of the the bill had silentlygone up by $10.This is connected to various diversionary tactics, which may beobstructive, obtuse, or needling. Forexample, if you quibble about the meaning of some word a person used,they may be quite happy about being corrected, since that meansthey’ve derailed you, or changed the subject. They may pick nits inyour wording, perhaps asking you to define “is”. They maydeliberately misunderstand you:”You said this happened five years before Hitler came to power. Whyare you so fascinated with Hitler ? Are you anti-Semitic ?”It is also connected to various rhetorical tricks, such asannouncing that there cannot be a question period because the speakermust leave. (But then he doesn’t leave.)
    • Argument By Fast Talking:if you go from one idea to the next quickly enough, the audience won’thave time to think. This is connected to Changing The Subject and (to some audiences) Argument By Personal Charm.However, some psychologists say that to understand what you hear,you must for a brief moment believe it. If this is true, then rapiddelivery does not leave people time to reject what they hear.
    • Having Your Cake (Failure To Assert, or Diminished Claim):almost claiming something, but backing out. For example, “It maybe, as some suppose, that ghosts can only be seen by certain so-calledsensitives, who are possibly special mutations with, perhaps,abnormally extended ranges of vision and hearing. Yet some claim weare all sensitives.”Another example: “I don’t necessarily agree with theliquefaction theory, nor do I endorse all of Walter Brown’s othermaterial, but the geological statements are informative.” Thestrange thing here is that liquefaction theory (the idea that theworld’s rocks formed in flood waters) was demolished in 1788. To”not necessarily agree” with it, today, is in the categoryof “not necessarily agreeing” with 2+2=3. But notice thatwriter implies some study of the matter, and only partial rejection.A similar thing is the failure to rebut. Suppose I raise an issue.The response that “Woodmorappe’s book talks about that”could possibly be a reference to a resounding rebuttal. Or perhaps theresponder hasn’t even read the book yet. How can we tell ? [I laterdiscovered it was the latter.]
    • Ambiguous Assertion:a statement is made, but it is sufficiently unclear that it leavessome sort of leeway. For example, a book about Washington politics didnot place quotation marks around quotes. This left ambiguity aboutwhich parts of the book were first-hand reports and which parts weresecond-hand reports, assumptions, or outright fiction.Of course, lack of clarity is not always intentional. Sometimesa statement is just vague.If the statement has two different meanings, this is Amphiboly.For example, “Last night I shot a burglar in my pyjamas.”
    • Failure To State:if you make enough attacks, and ask enough questions, you may neverhave to actually define your own position on the topic.
    • Outdated Information:information is given, but it is not the latest information on thesubject. For example, some creationist articles about theamount of dust on the moon quote a measurement made in the 1950’s.But many much better measurements have been done since then.
    • Amazing Familiarity:the speaker seems to have information that there is no possible wayfor him to get, on the basis of his own statements. For example:”The first man on deck, seaman Don Smithers, yawned lazily andfingered his good luck charm, a dried seahorse. To no avail ! Atnoon, the Sea Ranger was found drifting aimlessly, with every man ofits crew missing without a trace !”
    • Least Plausible Hypothesis:ignoring all of the most reasonable explanations. This makes thedesired explanation into the only one. For example: “I left asaucer of milk outside overnight. In the morning, the milk was gone.Clearly, my yard was visited by fairies.”There is an old rule for deciding which explanation is the mostplausible. It is most often called “Occam’s Razor”, and itbasically says that the simplest is the best. The current phrase amongscientists is that an explanation should be “the mostparsimonious”, meaning that it should not introduce new concepts(like fairies) when old concepts (like neighborhood cats) will do.On ward rounds, medical students love to come up with the mostobscure explanations for common problems. A traditional response is totell them “If you hear hoof beats, don’t automatically think ofzebras”.
    • Argument By Scenario:telling a story which ties together unrelated material, and thenusing the story as proof they are related.
    • Affirming The Consequent:logic reversal. A correct statement of the form “if P thenQ” gets turned into “Q therefore P”.For example,”All cats die; Socrates died; thereforeSocrates was a cat.”Another example: “If the earth orbits the sun, then the nearerstars will show an apparent annual shift in position relative to moredistant stars (stellar parallax). Observations show conclusively thatthis parallax shift does occur. This proves that the earth orbits thesun.” In reality, it proves that Q [the parallax] isconsistent with P [orbiting the sun]. But it might also beconsistent with some other theory. (Other theories did exist. Theyare now dead, because although they were consistent with a few facts,they were not consistent with all the facts.)Another example: “If space creatures were kidnapping peopleand examining them, the space creatures would probably hypnoticallyerase the memories of the people they examined. These people wouldthus suffer from amnesia. But in fact many people do suffer fromamnesia. This tends to prove they were kidnapped and examined byspace creatures.” This is also a LeastPlausible Hypothesis explanation.
    • Moving The Goalposts (Raising The Bar, Argument By Demanding Impossible Perfection):if your opponent successfully addresses some point, then say he mustalso address some further point. If you can make these points more andmore difficult (or diverse) then eventually your opponent must fail.If nothing else, you will eventually find a subject that youropponent isn’t up on.This is related to Argument By Question.Asking questions is easy: it’s answering them that’s hard.If each new goal causes a new question, this may get to be InfiniteRegression.It is also possible to lower the bar, reducing the burden on anargument. For example, a person who takes Vitamin C might claim thatit prevents colds. When they do get a cold, then they move thegoalposts, by saying that the cold would have been much worse if notfor the Vitamin C.
    • Appeal To Complexity:if the arguer doesn’t understand the topic, he concludes that nobodyunderstands it. So, his opinions are as good as anybody’s.
    • Common Sense:unfortunately, there simply isn’t a common-sense answer for manyquestions. In politics, for example, there are a lot of issues wherepeople disagree. Each side thinks that their answer is commonsense. Clearly, some of these people are wrong.The reason they are wrong is because common sense depends on thecontext, knowledge and experience of the observer. That is whyinstruction manuals will often have paragraphs like these:When boating, use common sense. Have one life preserver for eachperson in the boat.When towing a water skier, use common sense. Have one personwatching the skier at all times.If the ideas are so obvious, then why the second sentence ? Why do theyhave to spell it out ? The answer is that “use common sense”actually meant “pay attention, I am about to tell you somethingthat inexperienced people often get wrong.”Science has discovered a lot of situations which are far moreunfamiliar than water skiing. Not surprisingly, beginners find thatmuch of it violates their common sense. For example, many peoplecan’t imagine how a mountain range would form. But in fact anyone cantake good GPS equipment to the Himalayas, and measure for themselvesthat those mountains are rising today.If a speaker tells an audience that he supports using common sense,it is very possibly an AmbiguousAssertion.
    • Argument By Laziness (Argument By Uninformed Opinion):the arguer hasn’t bothered to learn anything about the topic. Henevertheless has an opinion, and will be insulted if his opinion isnot treated with respect. For example, someone looked at a picture onone of my webpages, and made a complaint which showed that he hadn’t evenskimmed through the words on the page. When I pointed this out, hereplied that I shouldn’t have had such a confusing picture.
    • Disproof By Fallacy:if a conclusion can be reached in an obviously fallacious way, thenthe conclusion is incorrectly declared wrong. For example,”Take the division 64/16. Now, canceling a 6 on top and a six onthe bottom, we get that 64/16 = 4/1 = 4.””Wait a second ! You can’t just cancel the six !””Oh, so you’re telling us 64/16 is not equal to 4, are you ?”Note that this is different from Reductio AdAbsurdum, where your opponent’s argument can lead to an absurdconclusion. In this case, an absurd argument leads to a normalconclusion.
    • Reductio Ad Absurdum:showing that your opponent’s argument leads to some absurdconclusion. This is in general a reasonable and non-fallaciousway to argue. If the issues are razor-sharp, it is a good way tocompletely destroy his argument. However, if the waters are a bitmuddy, perhaps you will only succeed in showing that your opponent’sargument does not apply in all cases, That is, using Reductio AdAbsurdum is sometimes using the Fallacy Of TheGeneral Rule. However, if you are faced with an argument that ispoorly worded, or only lightly sketched, Reductio Ad Absurdum may be agood way of pointing out the holes.An example of why absurd conclusions are bad things:Bertrand Russell, in a lecture on logic, mentioned that in the senseof material implication, a false proposition implies any proposition.A student raised his hand and said “In that case, given that 1 =0, prove that you are the Pope”. Russell immediately replied,”Add 1 to both sides of the equation: then we have 2 = 1. Theset containing just me and the Pope has 2 members. But 2 = 1, so ithas only 1 member; therefore, I am the Pope.”
    • False Compromise:if one does not understand a debate, it must be “fair” tosplit the difference, and agree on a compromise between theopinions. (But one side is very possibly wrong, and in any case onecould simply suspend judgment.) Journalists often invoke this fallacyin the name of “balanced” coverage.”Some say the sun rises in the east, some say it rises in the west;the truth lies probably somewhere in between.”Television reporters like balanced coverage so much that they maygive half of their report to a view held by a small minority of thepeople in question. There are many possible reasons for this, some ofthem good. However, viewers need to be aware of this tendency.
    • Fallacy Of The Crucial Experiment:claiming that some idea has been proved (or disproved) by a pivotaldiscovery. This is the “smoking gun” version of history.Scientific progress is often reported in such terms. This isinevitable when a complex story is reduced to a soundbite, but it’salmost always a distortion. In reality, a lot of background happensfirst, and a lot of buttressing (or retraction) happensafterwards. And in natural history, most of the theories are about howoften certain things happen (relative to some other thing). For thosetheories, no one experiment could ever be conclusive.
    • Two Wrongs Make A Right (Tu Quoque, You Too, What’s sauce forthe goose is sauce for the gander):a charge of wrongdoing is answered by a rationalization that othershave sinned, or might have sinned. For example, Bill borrows Jane’sexpensive pen, and later finds he hasn’t returned it. He tells himselfthat it is okay to keep it, since she would have taken his.War atrocities and terrorism are often defended in this way.Similarly, some people defend capital punishment on the groundsthat the state is killing people who have killed.This is related to Ad Hominem (Argument To TheMan).
    • Pious Fraud:a fraud done toaccomplish some good end, on the theory that the end justifies themeans.For example, a church in Canada had a statue of Christ whichstarted to weep tears of blood. When analyzed, the blood turned out tobe beef blood. We can reasonably assume that someone with access tothe building thought that bringing souls to Christ would justify hissmall deception.In the context of debates, a Pious Fraud could be a lie. More generally, it would be when an emotionallycommitted speaker makes an assertion that is shaded, distorted or evenfabricated. For example, British Prime Minister Tony Blair wasaccused in 2003 of “sexing up” his evidence that Iraq hadWeapons of Mass Destruction.Around the year 400, Saint Augustine wrote two books, De Mendacio[OnLying] and Contra Medacium[Against Lying], on this subject. Heargued that the sin isn’t in what you do (or don’t) say, but in yourintent to leave a false impression. He strongly opposed Pious Fraud.I believe that Martin Luther also wrote on the subject.