Logical Fallacies

Definition of a 'Fallacy'

A misconception resulting from flaw in reasoning, or a trick or illusion in thoughts that often succeeds in obfuscating facts/truth.
Fallacies marked by an * are more common.

Formal Fallacies

A formal fallacy is defined as an error that can be seen within the argument's form. Every formal fallacy is a non sequitur (or, an argument where the conclusion does not follow from the premise.)

Propositional Fallacies

Logic formulas (affirming a disjunct: A or B; A; therefore not B), (affirming the consent: A, then B; B, therefore A), (denying the antecedent: If A, then B; not A, therefore not B).

Example: William Shatner is Captain Kirk or he is in Miss Congeniality. William Shatner is in Miss Congeniality. Therefore he is not Captain Kirk.

Quantification Fallacies

Error in logic where the quantifiers of the premises are in contradiction to the conclusion’s quantifiers. (Example: when the argument has a universal premise and a particular conclusion.)

Example: All dogs hate some cats.

Syllogistic Fallacies

When logical fallacies occur in the syllogisms of deductive reasoning. This occurs with a reference to something general, and then makes a conclusion about something more specific.

Definition of a categorical syllogism is an argument with two premises: one syllogism and one conclusion.

Example: All sharks are fish (All S are P.) All salmon are fish ( All x are P) Therefore all salmon are sharks. (All x are P.)

Informal Fallacies

An informal fallacy refers to an argument whose proposed conclusion is not supported by the premises. This creates an unpersuasive or unsatisfying conclusion.

Ambiguity (Also Called "Hedging")*

The fallacy of ambiguity refers to the use of a double meaning or an unclear descriptive applied to mislead or misrepresent the truth. Then changing the meaning of the terms later. This is often done by politicians.)

Example: Bill Clinton's "I did not have sexual relations with that woman, Miss Lewinsky." (He later redefined the term "sexual relations" in the broad categorical understanding of that word, as opposed to the specific aspect which he was guilty of.)

Argument from Repetition (Argumentum ad Nauseam)

Argument from repetition refers to someone repeating a statement often in the hopes that the listener will begin to accept it as truth, instead of providing evidence.

Example: Hurtlocker deserves an Oscar. Other films have potential, but they do not deserve an Oscar like Hurtlocker does. Out of all the films up for an Oscar, Hurtlocker should be award one because it is the best film nominated and deserves an Oscar.

Ad Hominem*

The ad hominem attack is a logically fallacy associated with trying to undermine the opponent's arguments by personal attacks, through attacking their character or skill level, etc.

Example: Bill claims that this was an accident, but we know Bill to be a liar, so we can't take his word for it.

Anecdotal*

The anecdotal fallacy uses a personal experience or an isolated example instead of a sound argument.

Example: Leanne thinks smoking does not affect life expectancy since her grandmother smoked for 4 decades and lived to be 87.

Appeal to Emotion*

The fallacy of appeal to emotion makes a claim based on sympathy or empathetic instead of just or logical grounds.

Example: Sarah did not want to eat liverwurst for dinner, but he mother told her to think of all the starving children in the world who do not have food at all.

Appeal to Nature*

The fallacy of appeal to nature refers to the argument that just because something is natural that it is therefore valid, justified, or inevitable.

Example: "John was well within his rights to avenge his wife after he witnessed her being brutally murdered. Killing the murderer was the natural response."

Appeal to Authority*

The fallacy of appeal to authority makes the argument that if one credible source believes something that it must be true.

Example: If the Pope says that an aspect of doctrine is true, then it should be added to the creed, since he is infallible.

Bandwagon*

The fallacy of bandwagon says, “But everyone is doing it.” This fallacy appeal to the popularity of something as a means of validating it.

Example: A recent study shows 8 out of 10 doctors say that acupuncture is an effective therapy, therefore it must be since 8 out of 10 doctors can’t be wrong!

Begging the Question (Petitio Principii)*

Petitio principii presents circular arguments in which the conclusion is not include in the premises.

Example: Opium is known to put people to sleep because it contains soporific properties. (This is the same as saying "Opium puts people to sleep because it has elements that put people to sleep.")

Burden of Proof (Onus Probandi)*

This fallacy originates from the Latin phrase "onus probandi incumbit ei qui dicit, non ei qui negat"). The burden of proof is on the person who makes the claim, not on the person who denies (or questions) the claim. The fallacy of the Burden of Proof occurs when someone who is making a claim, puts the burden of proof on another party to disprove what they are claiming.

Example: Ellis: "I believe that God exists." Marty: "How can you prove it? Ellis: "I don’t have to, if you can't prove that He doesn't."

Circular Reasoning (Circulus in Demonstrando)*

The fallacy of circular logic occurs when the one reasoning begins with a claim they are trying to conclude with.

Example: Whatever is less dense than water will float, because such objects won't sink in water.

Continuum Fallcy

Also called the fallacy of the beard, line-drawing fallacy, fallacy of the heap, the sorites fallacy, and the bald man fallacy, the continuum fallacy rejects a claim because it is not precise. The is fallacious because, vague, "in-between" or unclear scenarios do not make them necessarily untrue.

Example: Ronnie has a full head of hair. If you pull one out, he will not be bald. If you pull another out, he still will not be bald. So no matter how many hairs you pull out, Ronnie will not be bald.

Equivocation*

The fallacy of equivocation uses misleading terms of more than one meaning without clarifying which definition is intended in the scenario.

Example: Philosophy students are taught how to argue, but shouldn't we teach them something more helpful? After all there are already a lot of arguments and conflicts in the world.

Etymological Fallacy*

The etymological fallacy poses that a certain term’s original meaning applies to its colloquial and modern understanding in current circumstances.

Example: "Lucy, why do you call your children 'kids?' Don’t you see how offensive it is to liken your children to immature little goats?"

Fallacy Fallacy*

This is an an argument that is based on false claims, but is logically coherent.

Example: Jenna thinks we should do yoga before work because it is natural and is said to relax you. Miles thinks we should also smoke pot before work for the same reasons.

Fallacy of Composition and Division*

The fallacy of composition and division makes the assumption that one part of something will apply to the whole, or that the whole must apply to all the parts.

Example: Each part of this chair is cheap, so the whole chair for sale must be cheap. (Composition) Healthy brains think. Healthy brains are comprised of nothing but brain cells. If healthy brains think, then the individual brain cells can think too. (Division)

False Dilemma*

Also called false dichotomy, fallacy of bifurcation, black-or-white fallacy, the false delamma presents two alternative states as the only possibilities when more possibilities may exist.

Example: You are either with me or against me.

False Cause & False Attribution*

False cause refers to an argument where someone cites sequential events as evidence that the first event caused the second. False attribution happens when someone appeals to irrelevant, biased, or unqualified information.

Example: False Cause I eat bananas for a snack every day. One day I skipped my banana, and my car was broken into. I have not missed a day of banana-snacking since.False Attribution John showed me this book that proved scientists have empirical evidence for the existence of mermaids, but I lost the book and don’t remember the title.

Fallacy of Quoting Out of Context

Also known as contextomy, the fallacy of quoting out of context occurs when an original phrase is distorted or a claim is misconstrued from its original meaning, by quoting it out of context.

Example: "One of the finest things ever done by a mob was the crucifixion of Christ…You see what I would have done is shipped him to Rome and fed him to the lions. They could never have made a savior out of mince meat."- Ben Hecht. This is an example of contextomy because the excerpt is from a novel and spoken by a fictional character. Thus quoting this section as if it was an opinion held by the author Ben Hecht, is not an accurate reflection of the author’s personal beliefs, but rather of the character who spoke it in his novel.

Furtive Fallacy

Furtive fallacy occurs when the outcomes seem to have been caused by the malfeasance of the decision makers involved.

Example: This is most evident in when historians or scientists write articles at great lengths in description of the lives of certain personages, or events for which there is not sufficient evidence to prove the claims.

Gambler's Fallacy*

The gambler's fallacy is based on the false belief that separate, independent events can affect the likelihood of another random event, or that if something happens often that it is less likely that the same will take place in the future.

Example: Edna had rolled a 6 with the dice the last 9 consecutive times. Surely it would be highly unlikely that she would roll another 6 on the 10th time.

Genetic Fallacy*

The genetic fallacy reasons that one can accurately judge or assess something as good or bad based on where it originates from.

Example: I was brought up Mormon, so I believe Mormonism is the truth, since my parents are good people and they wouldn't lie to me.

Inflation of Conflict

The fallacy of inflation of conflict assumes the belief that the instances where scholars and scientists have differing opinions on the something, it calls the credibility of the entire field into question.

Example: My piano teacher says I should practice one hour each day, but my father says I should practice three hours a day. They don't know what they are talking about, so I shouldn't practice at all.

Incomplete Comparison

An incomplete comparison occurs when two things are compared that are not really related, in order to make something more appealing than it is. This also happens when conclusions are made with incomplete information.

Example: Carrots have much less sugar than a gallon of chocolate syrup.

Ignoratio Elenchi

Also called Irrelevant Conclusion, the ignoratio elenchi fallacy reaches a relevant conclusion but misses the point. Though the claims and conclusion may be logically valid, they do not address the point in question.

Example: Hippos can't be dangerous to humans, because they are so calm and look so cute. (Proving an irrelevant conclusion. Also interesting to note, that of all animals, hippos cause the highest number of human deaths in Africa.)

Kettle Logic

Kettle logic is the use of several inconsistent arguments to defend a position.

Example: Someone accused of having sex in a public place might respond with an argument that they were not having sex in a public place, since the restroom was in a park, in a secluded location and the stall blocked them from public view.

Loaded Question*

The loaded question arises by asking a question that presupposes a claim so that it cannot be answered to without sounding guilty.

Example: "Marijuana has mind-numbing elements that affect your memory… so how can you say you have never had marijuana if you can't remember? Now exactly how much pot did you smoke?"

Middle Ground*

The middle ground fallacy argues that that a compromise between two extremes must be reached to satisfy a situation.

Example: Joe says the sky is pink and Liz says the sky is blue, so they should really just compromise and say the sky is purple.

No True Scotsman*

The no true Scotsman fallacy appeals to the "purity" of an ideal or standard as a way to dismiss relevant criticisms or flaws in your argument.

Example: John doesn't drink alcohol. No real man avoid alcohol. John isn't a real man.

Personal Incredulity*

The fallacy of personal incredulity occurs when one finds a concept difficult to understand, or simply does not fathom how it works, then they conclude believe that it is likely untrue.

Example: Irene was 89 years old, had never left the small town in Iowa where she was raised, and she had never seen a vessel. Though Michael had tried to describe what Navy life on the submarine would be like, she didn’t believe a word was true. How could a glorified metal tube sustain the lives of many men, while submerged for months at a time?

Proof by Verbosity

Also called argumentum verbosium, or proof by intimidation, proof by verbosity is an argument that is far too complicated and verbose for an opponent to reasonably address all the particulars, or the person making the argument is so well-reputed that one takes his claims as truth.

Example: Dr. Samuel Donovan solved a Rubik's Cube in 45 seconds; he won the Medal of Honor for his service in Vietnam, had given lectures across the world in microbiology, and was awarded a Pulitzer Prize; so I don't doubt that his claim is true about the egg coming before the chicken.

Proving Too Much

The fallacy of proving too much refers to an argument that reaches a conclusions which contradicts things that are known to be true, or contradicts the premises in that argument.

Example: One might argue that "all slavery is evil because there are cases where a slave was beaten to death." This is proving too much, because the same logic would reason that since some cases of domestic violence exist, that all marriage is evil.

Red Herring*

The red herring fallacy focuses on arguing for an irrelevant topic with the intention of distracting the audience, this usually happens when the orator finds another topic easier to outline.

Example: "I know I cheated on the test, Mrs. Holburn. But what am I going to do, my parents will kill me!"

Reification

Also called the Fallacy of Misplaced Concreteness, or hypostatization, the reification fallacy occurs when an argument relies on an abstract concept as if it were a concrete fact; when a hypothetical scenario or situation is referred to, and treated as if it were a real thing.

Example: "The ocean is calling me saying “Come play with me, and splash in the salty waves."

Retrospective Determinism

The fallacy of retrospective determinism argues that because something happened, it was inevitable.

Example: When Hitler decided to invade Russia, it was game over for the Nazis. This was because there was no way German troupes could survive the Russian winter, or cope with the vastness of the country.

Strawman*

The strawman fallacy occurs when one misrepresents an argument so that it becomes easier to attack.

Example: Those who oppose abortion have no respect for women's rights, and see women as baby-making machines, which is of course wrong. Women must be able to choose.

Shotgun Argumentation

The shotgun argumentation fallacy occurs when one chooses so many arguments, firing many shots as it were, in order to disable your opponent from answering them all.

Example: An angry sports fan might argue that his team lost because the lights were shut off in the middle of the game, and that the player in the forward position had a gimp knee so wasn't able to score as well, and that the refs kept yellow-carding the best players, and that there was a clear biased for the opposing team, so that is why they didn't win.

Slippery Slope*

The slippery slope fallacy consists of arguments that reason if something S were to happen, then something else P will eventually occur, so we should prohibit S from happening.

Example: If we let our child out of his room, eventually he will want to leave the house, and will end up on the street. If he is walking around on the street then he will be snatched up by a stranger and sold into slavery in a remote region on the World.

Special Pleading*

The special pleading fallacy occurs when the orator ignores certain elements that are unhelpful for their claims, or when one asks for special considerations to be given them or one of their premises.

Example: "Yes, I know convicted drug abuse justifies imprisonment. But my son is a good kid, your honor, and just fell in with the wrong crowd."

Texas Sharpshooter*

The Texas sharpshooter fallacy occurs when a speaker chooses a cluster of data to apply to their argument, or when they find a pattern that they can apply to a presumption.

Example: A recent study showed that the top 10 countries where Italian soda is most commonly consumed are also countries that have some of the lowest rankings in reported cases of depression. Therefore Italian soda makes people happy.

Tu Quoque*

Tu quoque is a fallacy answering criticism with criticism, or turning the argument back around on the other person. It also applied the logic that because someone has done something, that it justifies someone else doing the same thing.

Example: The Ancient Greeks were some of the greatest thinkers. They had slaves, so we should have slaves too.