Fallacies of Logic
A list of some logical fallacies
Table of Contents


A Fallacy of Ambiguity, where the ambiguity arises from the emphasis (accent) placed on a word or phrase.

Affirmation of the Consequent

An argument from the truth of a hypothetical statement, and the truth of the consequent to the truth of the antecedent. In the syllogism below, P is the antecedent and Q is the consequent:

* P implies Q
* Q is true <— Affirming the consequent
* Therefore: P is true

If P then Q, therefore, if Q then P.

Example 1: "Nibiru's arrival will create an increase in natural disasters like earthquakes. A massive earthquake occurred in Japan this March; therefore, Nibiru is arriving."
Example 2: "Tomato-eating fairies invade peoples' gardens and leave behind partially-eaten tomatoes. I see you have partially-eaten tomatoes on your plants; therefore, you've got tomato-eating fairies living in your garden."


An argument in the course of which at least one term is used in different senses. Also known as equivocation. There are several types of "fallacies of ambiguity," including Reification, Equivocation, Amphiboly, Composition, Division, and Accentus.

Example: "The Theory of Evolution is just that: a theory." (The word "theory" means something quite different in the scientific sense than it does in the everyday sense.)


A type of Fallacy of Ambiguity where the ambiguity involved is of an "amphibolous" (equivocal, uncertain) nature. Amphiboly is a syntactic error. The fallacy is caused by faulty sentence structure, and can result in a meaning not intended by the author. "The department store now has pants for men with 32 waists." (How many waists do you have? I have only one!)

Appeal to Simplicity

Presenting something as true or desirable because of its perceived simplicity.

Example 1: "I'm just a down-home country boy; I might not know much about all this complicated sciencey stuff but I know all about patriotism, so elect me."
Example 2: "My opponent's solution is so complicated, but mine's so simple!"

Appeal to Vanity

Exactly what it sounds like: appealing to a person's vanity to win them over to your side. This is often done in advertising by making a product appear elite or classy through advertising, or by claiming that people are more intelligent or whatever if they take your side.

Example 1: "A clever/intelligent/spiritual/compassionate/etc person would be able to immediately see the merit of my proposition."
Example 2: "You're the best, so you deserve our product."

Appeal to Tradition

The fallacy of claiming that because something is traditional, it cannot be wrong and is above scrutiny.

Example: "There's nothing wrong with selling a twelve-year-old girl as a bride. It's tradition!"

Association Fallacy

The fallacy of deciding that something is good or bad depending on whether it is associated with someone or something that is generally perceived as good or bad.

Example 1: "Adolf Hitler believed in evolution. Therefore, believing in evolution is bad and wrong."
Example 2: "Alcoholism is bad. Therefore, drinking any alcohol is bad."
Example 3: "The guru teaches love and unity, so he/she must be a good person and must be telling the truth." (Many evil people taught love and unity - EG, Jim Jones, Adolf Hitler. It's an effective manipulation tool since it appeals to our idealistic sides.)

Argument From Personal Incredulity

The fallacy of assuming that you personally find something unbelievable, it cannot be true.

Example 1: "I don't see how ancient humans could have built the pyramids by themselves. Therefore, aliens must have been involved."
Example 2: "I cannot think of any natural mechanism to explain how a radio works. Therefore, it must be magic."

Argumentum ad Antiquitam (Appeal to Antiquity)

A fallacy of asserting that something is right or good simply because it is old or because "that's the way it's always been."

Example 1: "Of course my product works. The (insert culture here) have been using it for centuries."
Example 2: "Men have always been in charge and women have always raised the children, so that must be the best way to do things."

Argumentum ad Baculum (Appeal to Force)

An argument that resorts to the threat of force to cause the acceptance of the conclusion. Ad baculum arguments also include threats of fear to cause acceptance (e.g., "Do this or you'll go to Hades when you die!" or "Might makes right.").

Argumentum ad Consequentiam (Appeal to Consequences)

An argument that tries to base the likelihood of something based on how desirable or undesirable it is. The consequences needn't even be real.

Example 1: "If our beliefs are true, then life has value and meaning. If our beliefs aren't true, life has no value or meaning. Therefore, our beliefs are true." (This is also a false dichotomy.)
Example 2: "If you stop believing what we teach you/leave our group, you'll go insane/go broke/be damned for eternity. Therefore, you must believe what we teach you."
Example 3: "I believe in fairies, because believing in fairies makes me happy."

Argumentum ad Crumenam (Appeal to Wealth)

Fallacy of believing that money is a criterion of correctness; that those with more money are more likely to be right.

Argumentum ad Hominem (Personal Attack)

An argument that attempts to disprove the truth of what is asserted by attacking the speaker rather than the speaker's argument. Another way of putting it: Fallacy where you attack someone's character instead of dealing with salient issues. There are three basic types of ad hominem arguments: (1) abusive, (2) circumstantial, and (3) tu quoque: Meaning "You Too!"

Example 1: "You're obviously criticizing us because you're just jealous of our success."
Example 2: "You're a woman! You can't know anything about this!"
Example 3: "The only reason you'd argue so hard against us is if you worked for Them."

Argumentum ad Ignorantiam (Appeal to Ignorance)

An argument that a proposition is true because it has not been shown to be false, or vice versa. Ad ignorantium arguments are also known as "appeals to ignorance." This fallacy has two forms:

* P is true, because it has not been proven false.
* P is false, because it has not been proven true.

Example: "I believe vampires exist, because you can't prove they don't!"

Argumentum ad Lazarum (Appeal to Poverty)

A fallacy of assuming that because someone is poor he or she is sounder or more virtuous than one who is wealthier. This fallacy is the opposite of the informal fallacy "argumentum ad crumenam."

Argumentum ad Misericordiam (Appeal to Pity)

An argument that appeals to pity for the sake of getting a conclusion accepted.

Example 1: "The world is in such terrible shape. Children are starving and people are dying of starvation and disease. Me and my group are just trying to do some good in the world."
Example 2: "We provide hope for people who don't have any. Why would you want to take away their hope?"
Example 3: "I know she mistreated you, but she's your own mother! How could you cut ties with the woman who birthed and raised you?"

Argumentum ad Nauseam

The incorrect belief that an assertion is more likely to be true the more often it is heard. An "argumentum ad nauseum" is one that employs constant repetition in asserting a truth.

Argumentum ad Novitam (Appeal to Novelty)

A fallacy of asserting that something is more correct simply because it is new or newer than something else. Or that something is better because it is newer. This type of fallacy is the opposite of the "argumentum ad antiquitam" fallacy.

Argumentum ad Numeram (Appeal to the Masses)

A fallacy that asserts that the more people who support or believe a proposition then the more likely that that proposition is correct; it equates mass support with correctness.

Example: "There are so many people who believe that Elvis is still alive that there must be something to it!"

Argumentum ad Populum (Appeal to Popularity)

An argument that appeals to the beliefs of the multitude (i.e., the "populace"). Another way of putting it: Speaker deals with passions of audience rather than with salient issues. Ad populum arguments often occur in (1) propaganda, (2) demagoguery, and (3) advertising.

Example: "Come join us to worship the Great Lord Snorglefroz. One million people can't be wrong!"

Argumentum ad Temperantiam (Argument to Moderation)

The fallacious assumption that when two opposing claims are made, the truth must lie somewhere in the middle. Also known as Fallacy of the Golden Mean or False Compromise.

Example 1: "You thinks the moon is made of rock and you think the moon is made of cheese. Did either one of you ever consider that it might be made of both?"

Argumentum ad Verecundiam (Appeal to Irrelevant Authority)

An argument in which an authority is appealed to on matters outside his/her field of authority. "Ad verecundiam" also refers to a fallacy of simply resorting to appeals to authority.

Example 1: "Dr. Brilliant Astrophysicist says that we could achieve world peace if we all stopped eating meat."
Example 2: "Even Mr. Clever Chemist believes the apocalypse will happen soon!"


Also referred to as the "black and white" fallacy, bifurcation is the presentation of a situation or condition with only two alternatives, whereas in fact other alternatives exist or can exist.

Example 1: "If you're not part of the solution, you're part of the problem." Note that there can be some truth to this: if you choose to stay "neutral" on an issue where one side clearly has an advantage over the other, you are essentially aiding the more powerful side by simply staying out of their way.
Example 2: "Either the universe came about all by itself, or it was created by the God of the Bible just as Genesis describes."

Circular Reasoning

See "Begging the Question".

Circulus in Probando

See "Begging the Question".


An argument in which one assumes that a whole has a property solely because its various parts have that property. Composition is a type of Fallacy of Ambiguity .

Example: A single cell has no consciousness. People are made of cells; therefore, people are not conscious.

Cherry Picking

See: Observational Selection

Converting a Conditional

See Affirming the Consequent

Cum Hoc, Ergo Propter Hoc (Correlation Equals Causation)

A and B occurred simultaneously, therefore A and B are related. A fallacy of correlation that links events because they occur simultaneously; one asserts that because two events occur together they are causally related, and leaves no room for other factors that may be the cause(s) of the events. This fallacy is similar to the "post hoc ergo propter hoc" fallacy.

Example 1: As New Age beliefs gained popularity, heart disease increased. Therefore, New Age beliefs cause heart disease.

Confusion of Correlation and Causation

See Cum Hoc Ergo Propter Hoc

Denial of the Antecedent

An argument in which one infers the falsity of the consequent from the truth of a hypothetical proposition, and the falsity of its antecedent.

* P implies Q
* Not-P
* Therefore: Not-Q

Example 1: "If it's snowing outside, then the weather must be cold. It isn't snowing right now, so it can't be cold outside."

Dicto Simpliciter (Sweeping Generalization)

This fallacy occurs when a general rule is applied to a particular situation in which the features of that particular situation render the rule inapplicable. A sweeping generalization is the opposite of a hasty generalization.

Example 1: "You promised you'd be there for me no matter what, so you have to help me rob the bank."
Example 2: "Forcing people to do things against their will is wrong. Therefore, it's wrong to make people with severe paranoid schizophrenia take their medication if they don't want it."


An argument in which one assumes that various parts have a property solely because the whole has that same property. Division is a type of Fallacy of Ambiguity.

Example 1: "If you put pure sodium into water, you'll create an explosion. Therefore, water is explosive."
Example 2: "People are conscious. People are made of cells. Therefore, cells are conscious."

"Don't you have more important things to worry about?"

An attempt to divert attention from the issue at hand by appealing "more important" problems. It is a fallacy because it makes no attempt to deal with the subject under discussion. See also Red Herring.

Enumeration of Favorable Circumstances

See Observational Selection

Excluded Middle

See Bifurcation


An argument in which an equivocal expression is used in one sense in one premise and in a different sense in another premise, or in the conclusion. Equivocal means (1) of uncertain significance; not determined, and (2) having different meanings equally possible. Equivocation is a type of Fallacy of Ambiguity. The opposite of equivocation is "unequivocation," in which a word always carries the same meaning through a given context. Equivocation is a type of Fallacy of Ambiguity.


The act of replacing an offensive or obnoxious term with something that sounds more pleasant. For example, calling a war a 'police action,' 'armed incursion,' 'protective reaction strike,' 'pacification,' safeguarding American interests,' etc.

False Analogy

An analogy is a partial similarity between the like features of two things or events on which a comparison can be made. A false analogy involves comparing two things that are NOT similar. Note that the two things may be similar in superficial ways, but not with respect to what is being argued.

An example of this would be the way crackpots who are shunned by legitimate scientists compare themselves to Galileo. The analogy is invalid because Galileo's opponents were not other scientists, but the Catholic Church. An accurate comparison to Galileo's situation would be the way some religious groups have stymied and prevented education about evolution and global warming.

False Dichotomy

See Bifurcation

Genetic Fallacy

A fallacy wherein the origin of a thing or claim is used to attack or elevate the thing/claim, rather than the actual significance or merits thing/claim itself.

Example 1: "I was brought up to believe that this interpretation of the Bible is correct. Therefore, his interpretation is wrong."
Example 2: "'Fag' isn't a homophobic slur; it originally meant 'piece of wood.'"


Some individuals or groups will try to make you feel guilty for questioning them and/or not following their beliefs and/or actions.

Example 1: "How can you hate on a bunch of people who are just trying to help others?" (Just because you're trying to help people doesn't mean you are. You might even be making things worse.)
Example 2: "You should finish your dinner. Other children out there are going hungry!"
Example 3: "The leader has sacrificed so much for the cause. Would you really abandon him like that after all he's done for us?" (What the leader has or hasn't done has no bearing on whether the cause is just.)
Example 4: "You should just be grateful she did this for you. After all, it's the thought that counts."

Hasty Generalization

An argument in which a proposition is used as a premise without attention given to some obvious condition that would affect the proposition's application. This fallacy is also known as the "hasty generalization." It is a fallacy that takes evidence from several, possibly unrepresentative, cases to a general rule; generalizing from few to many. Note the relation to statistics: Much of statistics concerns whether or not a sample is representative of a larger population. The larger the sample size, the better the representativeness. Note also that the opposite of a hasty generalization is a sweeping generalization.

Example 1: "I know all atheists hate religion, because the atheists I keep seeing on YouTube are all anti-religious."
Example 2: "I have a few friends who belong to your group and they don't think what we're doing is offensive, so you're clearly overreacting."


See Reification

Ignoratio Elenchi (Irrelevant Conclusion)

An argument that is supposed to prove one proposition but succeeds only in proving a different one. Ignoratio elenchi stands for "pure and simple irrelevance."

Illicit Process

A syllogistic argument in which a term is distributed in the conclusion, but not in the premises. One of the rules for a valid categorical syllogism is that if either term is distributed in the conclusion, then it must be distributed in the premises. There are two types of Illicit Process: Illicit Process of the Major Term and Illicit Process of the Minor Term.


e.g., Consider it reasonable for the Universe to continue to exist forever into the future, but judge absurd the possibility that it has infinite duration into the past.


The question asked has a presupposition which the answerer may wish to deny, but which he/she would be accepting if he/she gave anything that would count as an answer. Any answer to the question "Why does such-and-such happen?" presupposes that such-and-such does indeed happen.

Meaningless Question

(e.g., What happens when an irresistible force meets an immovable object? But if there is such a thing as an irresistible force, there can be no immovable objects, and vice versa);

Misunderstanding Statistics

e.g., President Dwight Eisenhower expressing astonishment and alarm on discovering that fully half of all Americans have below average intelligence.

Moving The Goalpost

Changing the goal you gave your opponent so you can avoid admitting defeat.

An example of this would be young Earth creationists who ask for evidence of evolution. When shown any number of documented cases for evolution, they claim that these are all examples of microevolution and what they want are examples of macroevolution. In fact, "macroevolution" is just a lot of what they call "microevolution" over long periods of time. They might as well ask for proof that oaks grow from acorns by demanding that someone produces an oak tree that grows to full maturity overnight.

Non Causa Pro Causa (False Cause)

An argument to reject a proposition because of the falsity of some other proposition that seems to be a consequence of the first, but really is not.

Non-Sequitur ("It does not follow")

An argument in which the conclusion is not a necessary consequence of the premises. Another way of putting this is: A conclusion drawn from premises that provide no logical connection to it.

Example 1: "Archaeologists have found stone age statuettes of the female body in Europe. This proves we used to be matriarchal."
Example 2: "Many famous people were mocked and laughed at before they were taken seriously, so laugh at me now, because my research will be famous!"

Observational Selection

Also called the enumeration of favorable circumstances, or as the philosopher Francis Bacon described it, 'counting the hits and forgetting the misses"

Example 1: A state boasts of the presidents it has produced, but is silent on its serial killers.
Example 2: Many professional "psychics" depend on people making this error. They will bombard clients with a series of questions and statements (a technique known as "shotgunning.") The client will usually latch onto the most accurate statements and forget the inaccurate statements because they want to believe the psychic is real.

Petito Principii (Begging the Question)

An argument that assumes as part of its premises the very conclusion that is supposed to be true. Another way of saying this is: Fallacy of assuming at the onset of an argument the very point you are trying to prove. The fallacy is also sometimes referred to as "Circulus in Probando," or "circular reasoning." The argument assumes its conclusion is true but DOES NOT SHOW it to be true. It has two forms:

* P is true, because P is true.
* P is true, because A is true. And A is true because B is true. And B is true because P is true.

Example 1: "This book is true because the author says it's true." (In fact, many stories that claim to be accurate representations of real events… aren't.)
Example 2: "This ex-member of the Illuminati is telling the truth because he's Christian now, and a Christian wouldn't lie."
Example 3: "Our ancestors didn't try to domesticate and conquer the world like people do today because they respected Mother Earth."

Post Hoc, Ergo Propter Hoc ("This happened before that, therefore this was the cause")

An argument from a premise of the form "A preceded B" to a conclusion of the form "A caused B." Simply because one event precedes another event in time does not mean that the first event is the cause of the second event. This argument resembles a fallacy known as a Hasty Generalization.

Example: "Just before I got into a fight with my girlfriend, I ate a carrot. Carrots must make me more prone to getting into fights."

Plurium Interrogationum (Many Questions)

A demand for a simple answer to a complex question, or for someone to answer a flurry of questions that they cannot possibly process. See also the Gish Gallop.

Poisoning The Well

The act of delegitimizing one's opponent before the opponent has even had the chance to make their case. A subtype of Ad Hominem attack.

Example 1: "Obviously this website is run by the government1 as a cover-up."
Example 2: "You can't believe anything our opponents say. Their hearts are corrupted by darkness."
Example 3: "Anyone who calls us crackpots is really working for Them."

Quaternio Terminorium (Fallacy of Four Terms)

An argument of the syllogistic form in which there occur four or more terms. In a standard categorical syllogism there are only three terms: a subject, a predicate, and a middle term.

Red Herring

A fallacy when irrelevant material is introduced to the issue being discussed, such that everyone's attention is diverted away from the points being made, and toward a different conclusion. It is not logically valid to divert a chain of reasoning with extraneous points.


To reify something is to convert an abstract concept into a concrete thing. Reification is a Fallacy of Ambiguity. Reification is also sometimes known as a fallacy of "hypostatization".

Secundum Quid

See Hasty Generalization

Shifting the Burden of Proof

The burden of proof is always on the person making the assertion or proposition. Shifting the burden of proof, a special case of "argumentum ad ignorantium," is a fallacy of putting the burden of proof on the person who denies or questions the assertion being made. The source of the fallacy is the assumption that something is true unless proven otherwise.

An example of this would be people who insist that you prove that Elenin isn't a brown dwarf, when in fact the burden of proof is on them - they need to demonstrate that it is a brown dwarf.

Short Term vs. Long Term

A subset of the excluded middle. (e.g., We can't afford programs to feed malnourished children and educate pre-school kids. We need to urgently deal with crime on the streets.)

Slippery Slope

Related to the excluded middle. (e.g., If we allow abortion in the first weeks of pregnancy, it will be impossible to prevent the killing of a full-term infant. Or, conversely: If the state prohibits abortion even in the ninth month, it will soon be telling us what to do with our bodies around the time of conception)

Someone Has It Worse Than You

This is an attempt to delegitimize what a person is saying by claiming they have no right to complain about something because somebody has it worse. It is a fallacy because it makes no attempt to deal with the subject under discussion.

Special Pleading

Special pleading is a logical fallacy wherein a double standard is employed by the person making the assertion. Special pleading typically happens when one insists upon less strict treatment for the argument he/she is making than he or she would make when evaluating someone else's arguments.

An example of this are people who claim that comedians should get a free pass for using slurs and ethnic stereotypes that wouldn't be acceptable anywhere else simply because it's comedy, as if being ''comedy'' somehow makes it exempt from the same scrutinies as any other form of entertainment.

Statistics of Small Numbers

A close relative of 'Observational Selection'. Having an inadequate sample size to prove one's conclusion.

Example: "Gay people love wearing clothes like that. I know because I have a gay friend, and he wears clothes like that all the time."

Straw Man

It is a fallacy to misrepresent someone else's position for the purposes of more easily attacking it, then to knock down that misrepresented position, and then to conclude that the original position has been demolished. It is a fallacy because it fails to deal with the actual arguments that one has made.

Example 1: "Evolutionists say life appeared when lightning hit a puddle!"
Example 2: "How could you criticize us when we just want to help the world? What's your problem with people trying to do good?" Many abusive groups and organizations use this line or a variation of it.

Suppressed Evidence/Half-Truths

(e.g., An amazingly accurate and widely quoted "prophecy" of the assassination attempt on President Reagan is shown on television; but was it recorded before or after the event?)

Example: "Scientists use carbon-14 dating to determine the age of Egyptian artifacts. But simply touching the artifact will contaminate it and give false results." As if every artifact ever found has been fatally contaminated and scientists don't know how to account for contamination when it does happen.

Tu Quoque (You, Too!)

When a person attempts to delegitimize their opponent by pointing out that the opponent is engaged in behavior that is just as bad, if not worse. It is a fallacy because it makes no attempt to deal with the subject under discussion.

Example: "You have no room to criticize me for what I do when what you do is just as bad!"

Undistributed Middle

A syllogistic argument in which the middle term of a categorical syllogism is not distributed in at least one of the premises.

Example: "Alien spacecrafts come from space. Comets come from space. Therefore, comets are alien spacecrafts."

Weasel Words

Weasel words are essentially empty words and meaningless phrases that are used to mislead the listener or reader into thinking more is being said than actually is. In the following examples, the weasel words are bolded:

Example 1: Experts agree that Nibiru is coming in 2012. Who are these experts?
Example 2: Many ancient prophecies predict Guru Lulu. Which ancient prophecies?
Example 3: Many feel the secularization of American culture is contributing to the decay of society. Who are these "many?" Also, feelings ain't necessarily fact.


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