Fallacies are errors in logic. In an argument that draws conclusions
from premises (i.e. evidence), logical errors occur when we
improperly use premises or incorrectly connect premises
to a conclusion. Logic is not concerned about the truthfulness
of individual premises, just the use of and relationship between statements.
Argumentum Ad Hominem: committed by attacking the person who's making an argument, rather than the argument itself. All below are types of argumentum ad hominem, so you may use the general term or the specific term.
Abusive ad Hominem: one of the most common fallacies, it is a direct attack on a person's character rather than focusing on his or her arguments.
Circumstantial ad Hominem: opposing speaker is accused of having vested interests.
- There is no way that Louis Althusser can provide a believable Structuralist Marxist philosophy; look at the guy, he strangled his wife to death.
- The Premier was convicted of drunk driving and now he is going to drive this province to ruin. I can't vote for him!
Poisoning the Well: an attempt to preclude discussion by using prior prejudice to attack the credibility of an opponent; “this expression goes back to the Middle Ages, when waves of anti-Jewish prejudice and persecution were common. If a plague struck a community, the people blamed it on the Jews, whom they accused of’poisoning the wells.”
- Of course he is against raising cigarette taxes; he smokes eight packs a day.
- Why should we listen to that politician if he is <pick your prejudice>?
Genetic Fallacy: the origins of a person, object or institution determine its character, nature or worth.
Tu Quoque: indicating that the opposing side made the same error; often times referred to as “you did it too!” (Pronounced as tu kwo kway)
- That lawyer has such a hot temper; she must be Italian.
- The new professor must be an excellent writer; he got his Ph.D. from Yale.
- If it's made in Japan, it must be a good car.
- Yes, I cheated on my examination, but I know you did it too when you were a student.
- Yes, we stole money, but so did other political parties!
Begging the Question (Petitio Principii ): premises that are passed on as being valid without supporting evidence. Sometimes the premise is proven by the conclusion itself, making the argument circular (see below).
- When combined, Public Affairs majors and unmotivated Liberal Arts Majors make up 30% of the student population; we really need to get rid of unproductive departments! (Unproven premise: Liberal Arts Majors are unmotivated).
Circular Argument: restating the premise in the conclusion rather than proving or disproving.
- President Kennedy was an excellent speech giver because he delivered exceptional speeches.
Common Sense Fallacy: an argument is held to be true because of practical truths and common sense. Common sense is sometimes correct, but all too many times all too commonly incorrect.
- We all know if it looks bad, it tastes bad. It's just common sense.
Complex Question (Fallacy of Loaded Question, Fallacy of the False Question): this is the interrogative form of circulus in demonstrando.
- How long did it take you to come up with that excuse for misreading the text?
- Which sources did you use to plagiarize your policy brief?
Composition: assumption that what is true of a part or whole, or a member of a group must be true of the whole or the group. Trying to compose the whole out of parts.
- A couple of people in that neighborhood have been charged of theft-- the whole neighborhood is full of theives.
- In a depression, businesses cut back. So, government, representing all of society, should cut its overall spending too.
- She can't even stomach the first lab, how she even going to finsh med school?
Either/Or (False Dilemma, Bifurcation): from the Latin bifurcus, meaning, “two pronged.” An oversimplification that assumingly reduces several alternatives to a mere binary opposition.
- You either shape up or ship out!
- There is only one way: my way or the highway!”
- If the agency does not approve my proposal, they can say goodbye forever to affordable transportation.
False Analogy (False Metaphor): an ambiguous comparison with more dissimilarities than similarities that are not acknowledged or even clearly explained.
- “ The Kennedys had spark and Jack had grown into a handsome man, a male swan rising out of the Billy the Kid version of an Irish duckling he had been when he was a young senator.” (Stanley Crouch, “Blues for Jackie”)
False Equivalence: a logical fallacy where there appears to be an equivalence between two competing sides, but when in fact there is none. Journalists often commit this fallacy when they compare two sides of a scientific debate in an attempt to provide a balance between a scientific and denialist point of view. However, there is no equivalence between the two sides, when one is supported by evidence, and the other side with little or no evidence, of which most is of low quality.
Hasty Generalization: drawing conclusions from too little of evidence and often relying on stereotypes.
- I have known several democrats who vacillate in their support of this policy; so all democrats don’t have an adamant stance concerning this policy.
- All lawyers are verbose and unethical.
Ignoring the Burden of Proof: Generally speaking, he who asserts must prove. An assertion is a statement offered as a conclusion without supporting evidence. Since an argument is defined as a logical relationship between premise and conclusion, a simple assertion is not an argument. Writers sometimes forget this, and their articles can be littered with assertion after assertion. In the end, the duty to support an assertion is on the writer, not the reader (like the burden of proof is on the accuser in court, rather than the accused).
- College students spend four years of their lives and thousands of dollars of their parents' money trying to get as little as possible out of their college education, provided only that they get their coveted diplomas.
- Really? On what do you base your generalization about wasteful students? Where is your proof?
Non Sequitur: in Latin, “it does not follow.” A conclusion that does not necessarily follow from the premises upon which it is based. Watch to see if the conclusion matches up with the introduction or the "body" evidence.
- If these politicians were patriotic, they would not question the President.
- All the students have high grades in their classes, so they must be excellent writers.
Novelty Fallacy: arguing that something is good (and better) just because it is new and different.
- Under New Management.
- New and Improved.
Post Hoc Ergo Propter Hoc (Coincidental Correlation): in Latin “after this, therefore because of this”; an error in casual relationships. Just because two events chronologically follow each other, does not necessarily mean that a cause and effect relationship exists—it is just mere coincidence.
- I forgot to read my assignment last night and we had a pop quiz.
- I washed my car so it just had to rain.
Relevance Fallacies: Fallacies of relevance are arguments in which the premises do not bear upon the drawn arguments even though they may appear to do; therefore, this makes them irrelevant.
Anonymous Authority: authority in question is not named.
Argumentum ad Baculum (Appeal to Force): Latin word for stick is baculum; someone in a position of authority supports their claim by threatening the audience with undesirable consequences, (which may be either ideological or brute force) if the audience does not accept the claim.
- Experts agree that drinking forty glasses of water a day is healthy.
- According to leading experts, the foreign policy is progressive.
Argumentum ad Ignoratiam: an argument is true because no evidence disproves its validity.
- My dad is the Dean of the college, so if you want keep your job an a professor, you will give me an “A” in this class.
- Vote for me, or you will be sorry.
- If you don’t vote for the tax increase, the community college will shut down.
- No one has complained about this public policy, so it is not unjust.
- No one has determined that the elusive Yeti does not exist, so I know it must exist in the thick forests of Alaska.
Argumentum ad Misericordiam (Appeal to Pity): “argument addressed to sense of mercy”: an argument that wins the reader's acceptance by mere pity.
- I work full time and am solely responsible for the financial support of my children. If I don't get an “A” on this examination, then I will lose my license to practice law and then I will lose my job at the law firm. If I am jobless, then my children will starve to death; therefore, you have to give me an “A.” (Somewhat of a slippery slope as well.)
- I was late to class because the electricity went out in my apartment.
Argumentum ad Populum (Fallacy of Mob Appeal, Appeal to the Masses): this fallacy can include a “nostalgic” appeal that arouses the audience's negative and positive emotions about institutions and ideas; this appeal commonly uses emotional language, and trite expressions that are irrelevant to the argument at hand.
Argumentum ad Verecundiam: John Locke gave this fallacy its Latin name, “argument addressed to sense of modesty”; using someone such as a celebrity to support your claim. It's also called the "false authority" fallacy.
- Elect me for President, and our country will get back to wholesome family values and apple pie.
- Back in the day when Americans worked hard, an apple was a treat.
- 50,000,000 Elvis fans can't be wrong!
- President Bush said that spiders are insects; therefore, spiders are insects.
Authority of One: justify an idea citing one source of expertise based as a reason for holding the idea.
Authority of a Select Few: justify an idea by citing a select source of expertise.
Authority of Tradition: justify an idea based on tradition.
Bandwagon: supporting a claim by stating that “everyone” believes or acts a particular way.
- We have always written the fiscal notes this way.
- I absolutely have to support the war, because every patriotic citizen does.
- Why be the only person who hasn’t voted Republican?
Rhetorical Question: not really presented as a question, but where there is an expected answer.
- Why should we pay taxes to an industry that is polluting the Mediterranean ocean?
Red Herring: avoiding the main argument by diversionary tactics such as following tangents.
- I forgot to go grocery shopping for you, but I did buy you a dozen roses because I love you.
- Yes, my grades are low, but I volunteer a lot of time to the non-profit sector.
Sincerity Fallacy: just because somebody sincerely believes something doesn't make that belief or that person correct.
- I'm voting for President Bush because he is a man of conviction.
Slippery Slope (Bad Precedent): assuming that a proposed step will set off an uncontrollable chain of undesirable events.
- If you don't stop smoking cigarettes, then you are going to start shooting heroin.
- If the FDA approves of putting fish hormones in tomatoes, and rejects the proposed policy, our vegetables will soon be injected with monkey hormones.
- If Vietnam falls to communism, then it will be Laos, then Thailand, and then all of Asia!
Special Pleading: committed by applying a double standard exemplified in choice of words.
- "I am firm; you are stubborn; he is pigheaded." (Bertrand Russell)
- Men sweat; women perspire. (TV ad)
Straw Man: distorting, misrepresenting or exaggerating someone's position so it's easier to refute. Attack the misrepresented position, or the weak, straw man (unreal person) and then conclude that the original position is incorrect or ridiculous. Here are two straw men in one example:
- Mr. and Mrs. Smith are arguing about cleaning out their basement. "Why, we just went through that old stuff last year," Mr. Smith exclaims. "Do we have to clean it out every day?"
aaa"There you go again," his wife retorts, "exaggerating as usual. Nobody said anything about doing it every day - it's just that you want to keep everything around forever, and that's ridiculous."
Sweeping Generalization: committed by applying a fair generalization, one usually true, to an exceptional case by ignoring the peculiarities of the case.
- If he can lose weight, then you can too.
- That particular diet works for him, so you should be successful with it too.
Engel, S. Morris. With Good Reason. 6th ed. Boston: Bedford/St.Martin's Press, 2000.
Lunsford, Andrea A., & Ruszkiewicz, J. Everything's an Argument. 2nd ed. Boston: Bedford/
aaaSt.Martin's Press, 2001.
McCrimmon, James. Writing With A Purpose, 7th ed. Palo Alto: Houghton Mifflin, 1980.
Moore, B.N., & Richard Parker. Critical Thinking, 4th ed. Toronto: Mayfield Publishing, 1986.