|A fallacy is a kind of error in
reasoning. The alphabetical list below contains 177 names of
the most common fallacies, and it provides explanations and
examples of each of them. Fallacies should not be persuasive,
but they often are. Fallacies may be created unintentionally,
or they may be created intentionally in order to deceive other
people. The vast majority of the commonly identified fallacies
involve arguments, although some involve explanations, or
definitions, or other products of reasoning. Sometimes the
term "fallacy" is used even more broadly to indicate any false
belief or cause of a false belief. The list below includes
some fallacies of these sorts, but most are fallacies that
involve kinds of errors made while arguing informally in
The discussion that precedes the list begins with an
account of the ways in which the term "fallacy" is
vague. Attention then turns to the number of competing
and overlapping ways to classify fallacies of
argumentation. For pedagogical purposes, researchers in
the field of fallacies disagree about the following topics:
which name of a fallacy is more helpful to students'
understanding; whether some fallacies should be de-emphasized
in favor of others; and which is the best taxonomy of the
fallacies. Researchers in the field are also deeply
divided about how to define the term "fallacy" itself, how to
define certain fallacies, and whether any general theory of
fallacies at all should be pursued if that theory's goal is to
provide necessary and sufficient conditions for distinguishing
between fallacious and non-fallacious reasoning generally.
Analogously, there is doubt in the field of ethics regarding
whether researchers should pursue the goal of providing
necessary and sufficient conditions for distinguishing moral
actions from immoral ones.
Table of Contents
(Clicking on the links below will take you to those parts of
The first known systematic study of fallacies was due to
Aristotle in his De Sophisticis Elenchis (Sophistical
Refutations), an appendix to the Topics. He listed
thirteen types. After the Dark Ages, fallacies were again
studied systematically in Medieval Europe. This is why
so many fallacies have Latin names. The third major period of
study of the fallacies began in the later twentieth century
due to renewed interest from the disciplines of philosophy,
logic, communication studies, rhetoric, psychology, and
The more frequent the error within public discussion and
debate the more likely it is to have a name. That is one
reason why there is no specific name for the fallacy of
subtracting five from thirteen and concluding that the answer
is seven, though the error is common among elementary school
The term "fallacy" is not a precise term. One reason is
that it is ambiguous. It can refer either to (a) a kind of
error in an argument, (b) a kind of error in reasoning
(including arguments, definitions, explanations, and so
forth), (c) a false belief, or (d) the cause of any of the
previous errors including what are normally referred to as
"rhetorical techniques". Philosophers who are researchers in
fallacy theory prefer to emphasize (a), but their lead is
often not followed in textbooks and public discussion.
Regarding (d), ill health, being a bigot, being hungry,
being stupid, and being hypercritical of our enemies are all
sources of error in reasoning, so they could qualify as
fallacies of kind (d), but they are not included in the
list below. On the other hand, wishful thinking, stereotyping,
being superstitious, rationalizing, and having a poor sense of
proportion are sources of error and are included in the
list below, though they wouldn't be included in a list devoted
only to faulty arguments. Thus there is a certain
arbitrariness to what appears in lists such as this. What have
been left off the list below are the following persuasive
techniques commonly used to influence others and to cause
errors in reasoning: apple polishing, exaggerating,
inappropriately assigning of the burden of proof, promising a
proof without producing it, using propaganda techniques,
ridiculing, being sarcastic, selecting terms with strong
negative or positive associations, using innuendo, and
weasling. All of the techniques are worth knowing about if one
wants to avoid the fallacies.
In describing the fallacies below, the custom is followed
of not distinguishing between a reasoner committing a fallacy
and the reasoning itself committing the fallacy, though it
would be more accurate to say that a reasoner commits
the fallacy and the reasoning contains the fallacy.
In the list below, the examples are very short. If they
were long, the article would be too long. Nevertheless real
arguments are often embedded within a very long discussion.
Richard Whately, one of the greatest of the 19th century
researchers into informal logic, wisely said, "A very
long discussion is one of the most effective veils of
Fallacy; ...a Fallacy, which when stated barely...would not
deceive a child, may deceive half the world if diluted
in a quarto volume."
2. Taxonomy of Fallacies
There are a number of competing and overlapping ways to
classify fallacies of argumentation. For example, they can be
classified as either formal or informal. A formal fallacy can
be detected by examining the logical form of the reasoning,
whereas an informal fallacy depends upon the content of the
reasoning and possibly the purpose of the reasoning. The list
below contains very few formal fallacies. Fallacious arguments
also can be classified as deductive or inductive, depending
upon whether the fallacious argument is most properly assessed
by deductive standards or instead by inductive standards.
Deductive standards demand deductive
validity, but inductive standards require inductive
strength such as making the conclusion more likely.
Fallacies can be divided into categories according to the
psychological factors that lead people to commit them, and
they can also be divided into categories according to the
epistemological or logical factors that cause the error.
In the latter division there are three categories: (1) the
reasoning is invalid but is presented as if it were a valid
argument, or else it is inductively much weaker than it is
presented as being, (2) the argument has an unjustified
premise, or (3) some relevant evidence has been ignored or
suppressed. Regarding (2), a premise can be justified or
warranted at a time even if we later learn that the premise
was false, and it can be justified if we are reasoning about
what would have happened even when we know it didn't happen.
Similar fallacies are often grouped together under a common
name intended to bring out how the fallacies are similar. Here
are three examples. Fallacies of relevance include
fallacies that occur due to reliance on an irrelevant
reason. In addition, ad
to pity, and affirming
the consequent are some other fallacies of relevance. Accent,
are examples of fallacies of ambiguity. The fallacies of
illegitimate presumption include begging
the question, false
true Scotsman, complex
question and suppressed
evidence. Notice how these categories don't fall
neatly into just one of the categories (1), (2), and (3)
For pedagogical purposes, researchers in the field of
fallacies disagree about the following topics: which name of a
fallacy is more helpful to students' understanding; whether
some fallacies should be de-emphasized in favor of others; and
which is the best taxonomy of the fallacies. Fallacy theory is
criticized by some teachers of informal reasoning for its
emphasis on poor reasoning rather than good. Do colleges teach
the Calculus by emphasizing all the ways one can make
mathematical mistakes? The critics want more emphasis on the
forms of good arguments and on the implicit rules that govern
proper discussion designed to resolve a difference of
opinion. But there has been little systematic study of
which emphasis is more successful.
4. What is a fallacy?
Researchers disagree about how to define the very term
"fallacy". Focusing just on fallacies in sense (a) above,
namely fallacies of argumentation, some researchers define a
fallacy as an argument that is deductively invalid or that has
very little inductive strength. Because examples of false
premises, and begging
the question are valid arguments in this sense, this
definition misses some standard fallacies. Other researchers
say a fallacy is a mistake in an argument that arises from
something other than merely false premises. But the
false dilemma fallacy is due to false premises. Still
other researchers define a fallacy as an argument that is not
good. Good arguments are then defined as those that are
deductively valid or inductively strong, and that contain only
true, well-established premises, but are not question-begging.
A complaint with this definition is that its requirement of
truth would improperly lead to calling too much scientific
reasoning fallacious; every time a new scientific discovery
caused scientists to label a previously well-established claim
as false, all the scientists who used that claim as a premise
would become fallacious reasoners. This consequence of the
definition is acceptable to some researchers but not to
others. Because informal reasoning regularly deals with
hypothetical reasoning and with premises for which there is
great disagreement about whether they are true or false, many
researchers would relax the requirement that every premise
must be true. One widely accepted definition defines a
fallacious argument as one that either is deductively invalid
or is inductively very weak or contains an unjustified premise
or that ignores relevant evidence that is available and that
should be known by the arguer. Finally, yet another theory of
fallacy says a fallacy is a failure to provide adequate proof
for a belief, the failure being disguised to make the proof
Other researchers recommend characterizing a fallacy as a
violation of the norms of good reasoning, the rules of
critical discussion, dispute resolution, and adequate
communication. The difficulty with this approach is that there
is so much disagreement about how to characterize these norms.
In addition, all the above definitions are often augmented
with some remark to the effect that the fallacies are likely
to persuade many reasoners. It is notoriously difficult to be
very precise about this vague and subjective notion of being
likely to persuade, and some researchers in fallacy theory
have therefore recommended dropping the notion in favor of
"can be used to persuade."
Some researchers complain that all the above definitions of
fallacy are too broad and do not distinguish between mere
blunders and actual fallacies, the more serious errors.
Researchers in the field are deeply divided, not only about
how to define the term "fallacy" and how to define some of the
individual fallacies, but also about whether any general
theory of fallacies at all should be pursued if that theory's
goal is to provide necessary and sufficient conditions for
distinguishing between fallacious and non-fallacious reasoning
generally. Analogously, there is doubt in the field of ethics
whether researchers should pursue the goal of providing
necessary and sufficient conditions for distinguishing moral
actions from immoral ones.
5. Other Controversies
In the field of rhetoric, the primary goal is to persuade
the audience. The audience is not going to be persuaded by an
otherwise good argument with true premises unless they
believe those premises are true. Philosophers tend to
de-emphasize this difference between rhetoric and informal
logic, and they concentrate on arguments that should fail to
convince the ideally rational reasoner rather than on
arguments that are likely not to convince audiences who hold
certain background beliefs.
Advertising in magazines and on television is designed to
achieve visual persuasion. And a hug or the fanning of fumes
from freshly baked donuts out onto the sidewalk are
occasionally used for visceral persuasion. There is some
controversy among researchers in informal logic as to whether
the reasoning involved in this nonverbal persuasion can always
be assessed properly by the same standards that are used for
6. Partial List of Fallacies
Consulting the list below will give a general idea of the
kind of error involved in passages to which the fallacy name
is applied. However, simply applying the fallacy name to a
passage cannot substitute for a detailed examination of the
passage and its context or circumstances because there are
many instances of reasoning to which a fallacy name might seem
to apply, yet, on further examination, it is found that in
these circumstances the reasoning is really not fallacious.
The accent fallacy is a fallacy of ambiguity due to the
different ways a word is emphasized or accented.
A member of Congress is asked by a reporter if
she is in favor of the President's new missile defense
system, and she responds, "I'm in favor of a missile defense
system that effectively defends America." With an
emphasis on the word "favor", this remark is likely to favor
the President's missile defense system. With an emphasis,
instead, on the words "effectively defends", this remark is
likely to be against the President's missile defense system.
Aristotle's fallacy of accent allowed only a shift in which
syllable is accented within a word.
We often arrive at a generalization but don't or can't list
all the exceptions. When we reason with the generalization as
if it has no exceptions, we commit the fallacy of accident.
This fallacy is sometimes called the fallacy of sweeping
People should keep their promises, right? I
loaned Dwayne my knife, and he said he'd return it. Now he
is refusing to give it back, but I need it right now to
slash up my neighbors' families. Dwayne isn't doing right by
me. People should keep their promises, but there
are exceptions as in this case of the psychopath who wants
Dwayne to keep his promise to return the knife.
Tactic and Appeal
to Emotions (Fear).
Psychologically, it is understandable that you would try to
rescue a cherished belief from trouble. When faced with
conflicting data, you are likely to mention how the conflict
will disappear if some new assumption is taken into account.
However, if there is no good reason to accept this saving
assumption other than that it works to save your cherished
belief, your rescue is an ad hoc rescue.
Yolanda: If you take four of these
tablets of vitamin C every day, you will never get a cold.
The burden of proof is definitely on
Yolanda's shoulders to prove that Juanita's vitamin C tablets
were probably "bad" -- that is, not really vitamin C. If
Yolanda can't do so, her attempt to rescue her
hypothesis (that vitamin C prevents colds) is simply a
dogmatic refusal to face up to the possibility of being wrong.
Juanita: I tried that last year for several
months, and still got a cold.
Yolanda: Did you
take the tablets every day?
Yolanda: Well, I'll bet you bought some bad
You commit this fallacy if you make an irrelevant attack on
the arguer and suggest that this attack undermines the
argument itself. It is a form of the Genetic
What she says about Johannes Kepler's astronomy
of the 1600's must be just so much garbage. Do you realize
she's only fourteen years old? This attack may
undermine the arguer's credibility as a scientific authority,
but it does not undermine her reasoning. That reasoning should
stand or fall on the scientific evidence, not on the arguer's
age or anything else about her personally.
If the fallacious reasoner points out irrelevant
circumstances that the reasoner is in, the fallacy is a
circumstantial ad hominem. Tu Quoque and Two
Wrongs Make a Right are other types of the ad hominem
The major difficulty with labeling a piece of reasoning as
an ad hominem fallacy is deciding whether the personal attack
is relevant. For example, attacks on a person for their
actually immoral sexual conduct are irrelevant to the quality
of their mathematical reasoning, but they are relevant to
arguments promoting the person for a leadership position in
the church. Unfortunately, many attacks are not so easy to
classify, such as an attack pointing out that the candidate
for church leadership, while in the tenth grade, intentionally
tripped a fellow student and broke his collar bone.
to the People.
to the People.
Affirming the Consequent
If you have enough evidence to affirm the consequent of a
conditional and then suppose that as a result you have
sufficient reason for affirming the antecedent, you commit the
fallacy of affirming the consequent. This formal fallacy is
often mistaken for modus ponens, which is a valid form of
reasoning also using a conditional. A conditional is an
if-then statement; the if-part is the antecedent, and the
then-part is the consequent. The following argument affirms
the consequent that she does speaks Portuguese.
If she's Brazilian, then she speaks Portuguese.
Hey, she does speak Portuguese. So, she is Brazilian.
If the arguer believes or suggests that the
premises definitely establish that she is Brazilian, then the
arguer is committing the fallacy. See the non
sequitur fallacy for more discussion of this point.
This is an error due to taking a grammatically ambiguous
phrase in two different ways during the reasoning.
In a cartoon, two elephants are driving their
car down the road in India. They say, "We've better not get
out here," as they pass a sign saying:
Upon one grammatical construction of
the sign, the pronoun "YOUR" refers to the elephants in the
car, but on another construction it refers to those humans who
are driving cars in the vicinity. Unlike equivocation,
which is due to multiple meanings of a phrase, amphiboly is
due to syntactic ambiguity, ambiguity caused by alternative
ways of taking the grammar.
PLEASE STAY IN YOUR CAR
If you discount evidence arrived at by systematic search or
by testing in favor of a few firsthand stories, you are
committing the fallacy of overemphasizing anecdotal evidence.
Yeah, I've read the health warnings on those
cigarette packs and I know about all that health research,
but my brother smokes, and he says he's never been sick a
day in his life, so I know smoking can't really hurt you.
This is the error of projecting uniquely human qualities
onto something that isn't human. Usually this occurs with
projecting the human qualities onto animals, but when it is
done to nonliving things, as in calling the storm cruel, the
fallacy is created. There is also, but less commonly, called
the Disney Fallacy or the Walt Disney Fallacy.
My dog is wagging his tail and running around
me. Therefore, he knows that I love him. The
fallacy would be averted if the speaker had said "My dog is
wagging his tail and running around me. Therefore, he is happy
to see me." Animals are likely to have some human emotions,
but not the ability to ascribe knowledge to other beings. Your
dog knows where it buried its bone, but not that you also know
where the bone is.
You appeal to authority if you back up your reasoning by
saying that it is supported by what some authority says on the
subject. Most reasoning of this kind is not fallacious.
However, it is fallacious whenever the authority
appealed to is not really an authority in this subject, when
the authority cannot be trusted to tell the truth, when
authorities disagree on this subject (except for the
occasional lone wolf), when the reasoner misquotes the
authority, and so forth. Although spotting a fallacious appeal
to authority often requires some background knowledge about
the subject or the authority, in brief it can be said that it
is fallacious to accept the word of a supposed authority when
we should be suspicious.
You can believe the moon is covered with dust
because the president of our neighborhood association said
so, and he should know. This is a fallacious
appeal to authority because, although the president is an
authority on many neighborhood matters, he is no authority on
the composition of the moon. It would be better to appeal to
some astronomer or geologist. If you place too much trust in
expert opinion and overlook any possibility that experts
talking in their own field of expertise make mistakes, too,
then you also commit the fallacy of appeal to authority.
Of course she's guilty of the crime. The police
arrested her, didn't they? And they're experts when it comes
Arguing that a belief is false because it implies something
you'd rather not believe. Also called Argumentum Ad
That can't be Senator Smith there in the
videotape going into her apartment. If it were, he'd be a
liar about not knowing her. He's not the kind of man who
would lie. He's a member of my congregation.Smith
may or may not be the person in that videotape, but this kind
of arguing should not convince us that it's someone else in
You commit the fallacy of appeal to emotions when someone's
appeal to you to accept their claim is accepted merely because
the appeal arouses your feelings of anger, fear, grief, love,
outrage, pity, pride, sexuality, sympathy, relief, and so
forth. Example of appeal to relief from grief:
[The speaker knows he is talking to an aggrieved
person whose house is worth much more than $100,000.] You
had a great job and didn't deserve to lose it. I wish I
could help somehow. I do have one idea. Now your family
needs financial security even more. You need cash. I can
help you. Here is a check for $100,000. Just sign this
standard sales agreement, and we can skip the realtors and
all the headaches they would create at this critical time in
your life. There is nothing wrong with using
emotions when you argue, but it's a mistake to use emotions as
the key premises or as tools to downplay relevant
information. Regarding the fallacy of appeal
to pity, it is proper to pity people who have had
misfortunes, but if as the person's history instructor you
accept Max's claim that he earned an A on the history quiz
because he broke his wrist while playing in your college's
last basketball game, then you've committed the fallacy of appeal
to pity. However, if you realize he didn't earn the
A, but nevertheless you still give him an A, then you have not
committed the fallacy, but you may have acted improperly.
The fallacy of appeal to ignorance comes in two forms: (1)
Not knowing that a certain statement is true is taken to be a
proof that it is false. (2) Not knowing that a statement is
false is taken to be a proof that it is true. The fallacy
occurs in cases where absence of evidence is not good enough
evidence of absence. The fallacy uses an unjustified attempt
to shift the burden of proof. The fallacy is also called
"Argument from Ignorance."
Nobody has ever proved to me there's a God, so I
know there is no God. This kind of reasoning is
generally fallacious. It would be proper reasoning only if the
proof attempts were quite thorough, and it were the case that
if God did exist, then there would be a discoverable proof of
to the Masses
to the People.
The fallacy of appeal to money uses the error of supposing
that, if something costs a great deal of money, then it must
be better, or supposing that if someone has a great deal of
money, then they're a better person in some way unrelated to
having a great deal of money. Similarly it's a mistake to
suppose that if something is cheap it must be of inferior
quality, or to suppose that if someone is poor financially
then they're poor at something unrelated to having money.
He's rich, so he should be the president of our
Parents and Teachers Organization.
to the People
If you suggest too strongly that someone's claim or
argument is correct simply because it's what most everyone
believes, then you've committed the fallacy of appeal to the
people. Similarly, if you suggest too strongly that someone's
claim or argument is mistaken simply because it's not what
most everyone believes, then you've also committed the
fallacy. Agreement with popular opinion is not necessarily a
reliable sign of truth, and deviation from popular opinion is
not necessarily a reliable sign of error, but if you assume it
is and do so with enthusiasm, then you're guilty of committing
this fallacy. It is also called mob appeal, appeal to the
gallery, argument from popularity, and argumentum ad populum.
The 'too strongly' is important in the description of the
fallacy because what most everyone believes is, for that
reason, somewhat likely to be true, all things considered.
However, the fallacy occurs when this degree of support is
You should turn to channel 6. It's the most
watched channel this year.This is fallacious
because of its implicitly accepting the questionable premise
that the most watched channel this year is, for that reason
alone, the best channel for you.
Appeal to Unqualified Authority
Argument from Outrage
Argument from Popularity
to the People.
Argumentum Ad ....
See Ad .... without the word "Argumentum."
A reasoner who is supposed to address an issue but instead
goes off on a tangent has committed the fallacy of avoiding
the issue. Also called missing the point, straying off the
subject, digressing, and not sticking to the issue.
A city official is charged with corruption for
awarding contracts to his wife's consulting firm. In
speaking to a reporter about why he is innocent, the city
official talks only about his wife's conservative wardrobe,
the family's lovable dog, and his own accomplishments in
supporting Little League baseball. However, the
fallacy isn't committed by a reasoner who says that
some other issue must first be settled and then continues by
talking about this other issue, provided the reasoner is
correct in claiming this dependence of one issue on the other.
Avoiding the Question
The fallacy of avoiding the question is a type of fallacy
of avoiding the issue that occurs when the issue is how to
answer some question. The fallacy is committed when someone's
answer doesn't really respond to the question asked.
Question: Would the Oakland Athletics be
in first place if they were to win tomorrow's game?
Answer: What makes you think they'll ever win
If you suggest that someone's claim is correct simply
because it's what most everyone is coming to believe, then
you're committing the bandwagon fallacy. Get up here with us
on the wagon where the band is playing, and go where we go,
and don't think too much about the reasons. The Latin term for
this fallacy of appeal to novelty is Argumentum ad Novitatem.
[Advertisement] More and more people are buying
sports utility vehicles. Isn't it time you bought one, too?
[You commit the fallacy if you buy the vehicle solely
because of this advertisement.]Like its close
cousin, the fallacy of appeal to the people, the bandwagon
fallacy needs to be carefully distinguished from properly
defending a claim by pointing out that many people have
studied the claim and have come to a reasoned conclusion that
it is correct. What most everyone believes is likely to be
true, all things considered, and if one defends a claim on
those grounds, this is not a fallacious inference. What is
fallacious is to be swept up by the excitement of a new idea
or new fad and to unquestionably give it too high a degree of
your belief solely on the grounds of its new popularity,
perhaps thinking simply that 'new is better.'
A form of circular
reasoning in which a conclusion is derived from premises
that presuppose the conclusion. Normally, the point of good
reasoning is to start out at one place and end up somewhere
new, namely having reached the goal of increasing the degree
of reasonable belief in the conclusion. The point is to make
progress, but in cases of begging the question there is no
"Women have rights," said the Bullfighters
Association president. "But women shouldn't fight bulls
because a bullfighter is and should be a man."
The president is saying basically that women
shouldn't fight bulls because women shouldn't fight bulls.
This reasoning isn't making an progress toward determining
whether women should fight bulls.
Insofar as the conclusion of a deductively valid argument
is "contained" in the premises from which it is deduced, this
containing might seem to be a case of presupposing, and thus
any deductively valid argument might seem to be begging the
question. It is still an open question among logicians as to
why some deductively valid arguments are considered to be
begging the question and others are not. Some logicians
suggest that, in informal reasoning with a deductively valid
argument, if the conclusion is psychologically new insofar as
the premises are concerned, then the argument isn't an example
of the fallacy. Other logicians suggest that we need to look
instead to surrounding circumstances, not to the psychology of
the reasoner, in order to assess the quality of the argument.
For example, we need to look to the reasons that the reasoner
used to accept the premises. Was the premise justified on the
basis of accepting the conclusion? A third group of logicians
say that, in deciding whether the fallacy is committed, we
need more. We must determine whether any premise that is key
to deducing the conclusion is adopted rather blindly or
instead is a reasonable assumption made by someone accepting
their burden of proof. The premise would here be termed
reasonable if the arguer could defend it independently of
accepting the conclusion that is at issue.
The black-or-white fallacy is a false
dilemma fallacy that unfairly limits you to only two
Well, it's time for a decision. Will you
contribute $10 to our environmental fund, or are you on the
side of environmental destruction? A proper
challenge to this fallacy could be to say, "I do want to
prevent the destruction of our environment, but I don't want
to give $10 to your fund. You are placing me between a rock
and a hard place." The key to diagnosing the black-or-white
fallacy is to determine whether the limited menu is fair or
unfair. Simply saying, "Will you contribute $10 or won't you?"
is not unfair.
This is another name for the Fallacy of Suppressed
Circular reasoning occurs when the reasoner begins with
what he or she is trying to end up with. The most well known
examples are cases of the fallacy of begging the question.
However, if the circle is very much larger, including a wide
variety of claims and a large set of related concepts, then
the circular reasoning can be informative and so is not
considered to be fallacious. For example, a dictionary
contains a large circle of definitions that use words which
are defined in terms of other words that are also defined in
the dictionary. Because the dictionary is so informative, it
is not considered as a whole to be fallacious. However, a
small circle of definitions is considered to be fallacious.
Definition: A couch is a sofa.For additional difficulties in deciding
whether an argument is deficient because it is circular, see
sofa is a davenport.
Definition: A davenport is a
Circumstantial Ad Hominem
to the People and Traditional
This fallacy occurs during causal reasoning when a causal
connection between two kinds of events is claimed when
evidence is available indicating that both are the effect of a
Noting that the auto accident rate rises and
falls with the rate of use of windshield wipers, one
concludes that the use of wipers is somehow causing auto
accidents. However, it's the rain that's the
common cause of both.
to the People and Traditional
You commit this fallacy when you frame a question so that
some controversial presupposition is made by the wording of
[Reporter's question] Mr. President: Are you
going to continue your policy of wasting taxpayer's money on
missile defense?The question unfairly presumes
the controversial claim that the policy really is a waste of
money. The fallacy of complex question is a form of begging
The composition fallacy occurs when someone mistakenly
assumes that a characteristic of some or all the individuals
in a group is also a characteristic of the group itself, the
group "composed" of those members. It is the converse of the
Each human cell is very lightweight, so a human
being composed of cells is also very lightweight.
The tendency to look only for evidence in
favor of one's controversial hypothesis and not to look for
disconfirming evidence, or to pay insufficient attention to
it. This is the most common kind of Fallacy
of Selective Attention.
She loves me, and there are so many ways that
she has shown it. When we signed the divorce papers in
her lawyer's office, she wore my favorite color. When
she slapped me at the bar and called me a "handsome pig,"
she used the word "handsome" when she didn't have to.
When I called her and she said never to call her again, she
first asked me how I was doing and whether my life had
changed. When I suggested that we should have children
in order to keep our marriage together, she laughed.
If she can laugh with me, if she wants to know how I am
doing and whether my life has changed, and if she calls me
"handsome" and wears my favorite color on special occasions,
then I know she really loves me.
Committing the fallacy of confirmation bias is
often a sign that one has adopted some belief dogmatically and
isn't seriously setting about to confirm or disconfirm the
Fallacy of argumentum consensus gentium (argument from the
consensus of the nations). See Traditional
If we reason by paying too much attention to exceptions to
the rule, and generalize on the exceptions, we commit this
fallacy. This fallacy is the converse of the accident fallacy.
It is a kind of Hasty
I've heard that turtles live longer than
tarantulas, but the one turtle I bought lived only two days.
I bought it at Dowden's Pet Store. So, I think that turtles
bought from pet stores do not live longer than tarantulas.
The original generalization is "Turtles live
longer than tarantulas." There are exceptions, such as the
turtle bought from the pet store. Rather than seeing this for
what it is, namely an exception, the reasoner places too much
trust in this exception and generalizes on it to produce the
faulty generalization that turtles bought from pet stores do
not live longer than tarantulas.
Cum Hoc, Ergo Propter Hoc
Latin for "with this, therefore because of this." This is a
cause fallacy that doesn't depend on time order (as does
the post hoc fallacy), but on any other chance correlation of
the supposed cause being in the presence of the supposed
Gypsies live near our low-yield cornfields. So,
gypsies are causing the low yield.
The definist fallacy occurs when someone unfairly defines a
term so that a controversial position is made easier to
defend. Same as the Persuasive
During a controversy about the truth or falsity
of atheism, the fallacious reasoner says, "Let's define
'atheist' as someone who doesn't yet realize that God
You are committing a fallacy if you deny the antecedent of
a conditional and then suppose that doing so is a sufficient
reason for denying the consequent. This formal fallacy is
often mistaken for modus tollens, a valid form of argument
using the conditional. A conditional is an if-then statement;
the if-part is the antecedent, and the then-part is the
If she were Brazilian, then she would know that
Brazil's official language is Portuguese. She isn't
Brazilian; she's from London. So, she surely doesn't know
this about Brazil's language.
Merely because a group as a whole has a characteristic, it
often doesn't follow that individuals in the group have that
characteristic. If you suppose that it does follow, when it
doesn't, you commit the fallacy of division. It is the
converse of the composition
Joshua's soccer team is the best in the division
because it had an undefeated season and shared the division
title, so Joshua, who is their goalie, must be the best
goalie in the division.
There are many situations in which you should judge two
things or people by the same standard. If in one of those
situations you use different standards for the two, you commit
the fallacy of using a double standard.
I know we will hire any man who gets over a 70
percent on the screening test for hiring Post Office
employees, but women should have to get an 80 to be hired
because they often have to take care of their children.
This example is a fallacy if it can be presumed
that men and women should have to meet the same standard for
becoming a Post Office employee.
Equivocation is the illegitimate switching of the meaning
of a term during the reasoning.
The term "nobody" changes its
meaning without warning in the passage. So does the term
"political jokes" in this joke: I don't approve of political
jokes. I've seen too many of them get elected.
Brad is a nobody, but since nobody is perfect, Brad must
be perfect, too.
The etymological fallacy occurs whenever someone falsely
assumes that the meaning of a word can be discovered from its
etymology or origins.
The word "vise" comes from the Latin "that which
winds", so it means anything that winds. Since a hurricane
winds around its own eye, it is a vise.
The fallacy of every and all turns on errors due to the
order or scope of the quantifiers "every" and "all" and "any."
This is a version of the scope
Every action of ours has some final end. So,
there is some common final end to all our
actions.In proposing this fallacious argument,
Aristotle believed the common end is the supreme good, so he
had a rather optimistic outlook on the direction of history.
When we overstate or overemphasize a point that is a
crucial step in a piece of reasoning, then we are guilty of
the fallacy of exaggeration. This is a kind of error
She's practically admitted that she intentionally yelled
at that student while on the playground in the fourth
grade. That's assault. Then she said nothing
when the teacher asked, "Who did that?" That's lying,
plain and simple. Do you want to elect as secretary of
this society someone who is a known liar prone to
assault? Doing so would be a disgrace to the Collie
When we exaggerate in order to make a joke, though, we
aren't guilty of the fallacy.
Dilemma or Black-or-White.
When reasoning by analogy, the fallacy occurs when the
analogy is irrelevant or very weak or when there is a more
relevant disanalogy. See also Faulty
The book Investing for Dummies really
helped me understand my finances better. The book Chess
for Dummies was written by the same author, was
published by the same press, and costs about the same
amount. So, this chess book would probably help me
understand my finances.
Improperly concluding that one thing is a cause of another.
The Fallacy of Non Causa Pro Causa is another name for this
fallacy. Its four principal kinds are the Post Hoc
Fallacy, the Fallacy of Cum
Hoc, Ergo Propter Hoc, the Regression
Fallacy, and the Fallacy of Reversing
My psychic adviser says to expect bad things
when Mars is aligned with Jupiter. Tomorrow Mars will be
aligned with Jupiter. So, if a dog were to bite me tomorrow,
it would be because of the alignment of Mars with
Dilemma or Black-or-White.
A reasoner who unfairly presents too few choices and then
implies that a choice must be made among this short menu of
choices commits the false dilemma fallacy, as does the person
who accepts this faulty reasoning.
I want to go to Scotland from London. I
overheard McTaggart say there are two roads to Scotland from
London: the high road and the low road. I expect the
high road is dangerous because it's through the hills. But
it's raining, so both roads are probably slippery. I
don't like either choice, but I guess I should take the low
road.This would be fine reasoning is you were
limited to only two roads, but you've falsely gotten yourself
into a dilemma with such reasoning. There are many other ways
to get to Scotland. Don't limit yourself to these two choices.
You can take other roads, or go by boat or train or airplane.
Think of the unpleasant choice as a charging bull. By
demanding other choices beyond those on the unfairly limited
menu, you thereby "go between the horns" of the dilemma, and
are not gored. For another example of the fallacy,
This is the fallacy of offering a bizarre (far-fetched)
hypothesis as the correct explanation without first ruling out
more mundane explanations.
Look at that mutilated cow in the field, and see
that flattened grass. Aliens must have landed in a flying
saucer and savaged the cow to learn more about the beings on
If you try to make a point about something by comparison,
and if you do so by comparing it with the wrong thing, you
commit the fallacy of faulty comparison or the fallacy of questionable
We gave half the members of the hiking club
Durell hiking boots and the other half good-quality tennis
shoes. After three months of hiking, you can see for
yourself that Durell lasted longer. You, too, should use
Durell when you need hiking boots. Shouldn't
Durell hiking boots be compared with other hiking boots, not
with tennis shoes?
Formal fallacies are all the cases or kinds of reasoning
that fail to be deductively valid. Formal fallacies are also
called logical fallacies or invalidities.
Some cats are tigers. Some tigers are animals.
So, some cats are animals. This might at first
seem to be a good argument, but actually it is fallacious
because it has the same logical form as the following more
obviously invalid argument:
Some women are Americans. Some Americans are
men. So, some women are men.
Nearly all the infinity of types of invalid
inferences have no specific fallacy names.
The fallacy of four terms (quaternio terminorum) occurs
when four rather than three categorical terms are used in a
All rivers have banks. All banks have vaults.
So, all rivers have vaults.The word "banks"
occurs as two distinct terms, namely river bank and financial
bank, so this example also is an equivocation.
Without an equivocation, the four term fallacy is trivially
This fallacy occurs when the gambler falsely assumes that
the history of outcomes will affect future outcomes.
I know this is a fair coin, but it has come up
heads five times in a row now, so tails is due on the next
toss. The fallacious move was to conclude that
the probability of the next toss coming up tails must be more
than a half. The assumption that it's a fair coin is important
because, if the coin comes up heads five times in a row, one
would otherwise become suspicious that it's not a fair coin
and therefore properly conclude that the probably is high that
heads is more likely on the next toss.
A critic commits the genetic fallacy if the critic attempts
to discredit or support a claim or an argument because of its
origin (genesis) when such an appeal to origins is irrelevant.
Whatever your reasons are for buying that DVD
they've got to be ridiculous. You said yourself that you got
the idea for buying it from last night's fortune cookie.
Cookies can't think!Fortune cookies are not
reliable sources of information about what DVD to buy, but the
reasons the person is willing to give are likely to be quite
relevant and should be listened to. The speaker is committing
the genetic fallacy by paying too much attention to the
genesis of the idea rather than to the reasons offered for it.
hominem fallacy is one kind of genetic fallacy, but the
genetic fallacy in our passage isn't an ad hominem.
If I learn that your plan for building the shopping center
next to the Johnson estate originated with Johnson himself,
who is likely to profit from the deal, then my pointing out to
the planning commission the origin of the deal would be
relevant in their assessing your plan. Because not all appeals
to origins are irrelevant, it sometimes can be difficult to
decide if the fallacy has been committed. For example, if
Sigmund Freud shows that the genesis of a person's belief in
God is their desire for a strong father figure, then does it
follow that their belief in God is misplaced, or does this
reasoning commit the genetic fallacy?
A reasoner commits the group think fallacy if he or she
substitutes pride of membership in the group for reasons to
support the group's policy. If that's what our group thinks,
then that's good enough for me. It's what I think, too.
"Blind" patriotism is a rather nasty version of the fallacy.
We K-Mart employees know that K-Mart brand items
are better than Wall-Mart brand items because, well, they
are from K-Mart, aren't they?
Guilt by association is a version of the ad
hominem fallacy in which a person is said to be guilty of
error because of the group he or she associates with.
Secretary of State Dean Acheson is soft on
communism as you can see by the fuzzy-headed liberals who
come to his White House cocktail parties and the bleeding
hearts of his Democratic Party who call for "moderation and
constraint" against Soviet terror.Has any
evidence been presented here that Acheson's actions are
inappropriate in regards to communism? This sort of reasoning
is an example of McCarthyism, the technique of smearing
liberal Democrats that was so effectively used by the late
Senator Joe McCarthy in the early 1950s. In fact, Acheson was
strongly anti-communist and the architect of President
Truman's firm policy of containing Soviet power.
A hasty generalization is a fallacy of jumping
to conclusions in which the conclusion is a
generalization. See also Biased
I've met two people in Nicaragua so far, and
they were both nice to me. So, all people I will meet in
Nicaragua will be nice to me.
You are hedging if you refine your claim simply to avoid
counterevidence and then act as if your revised claim is the
same as the original.
Samantha: David is a totally selfish person.
You don’t commit the fallacy if you
explicitly accept the counterevidence, admit that your
original claim is incorrect, and then revise it so that it
avoids that counterevidence.
Yvonne: I thought we was a boy scout leader. Don’t you
have to give a lot of your time for that?
Well, David’s totally selfish about what he gives money to.
He won’t spend a dime on anyone else.
Yvonne: I saw him
bidding on things at the high school auction fundraiser.
Samantha: Well, except for that he’s totally selfish
This is an error in reasoning due to confusing the knowing
of a thing with the knowing of it under all its various names
You claim to know Socrates, but you must be
lying. You admitted you didn't know the hooded man over
there in the corner, but the hooded man is Socrates.
Ignoring a Common Cause
The fallacy occurs when we accept an inconsistent set of
claims, that is, when we accept a claim that logically
conflicts with other claims we hold.
I'm not racist. Some of my best friends are
white. But I just don't think that white women love their
babies as much as our women do.
That last remark implies the speaker is a racist,
although the speaker doesn't notice the inconsistency.
Drawing a statistical conclusion from a set of data that is
clearly too small.
A pollster interviews ten London voters in one
building about which candidate for mayor they support, and
upon finding that Churchill receives support from six of the
ten, declares that Churchill has the majority support of
This fallacy is a form of the Fallcy of Jumping
The mistake of treating different descriptions or names of
the same object as equivalent even in those contexts in which
the differences between them matter. Reporting someone's
beliefs or assertions or making claims about necessity or
possibility can be such contexts. In these contexts, replacing
a description with another that refers to the same object is
not valid and may turn a true sentence into a false one.
Michelle said she wants to meet her new neighbor
Stalnaker tonight. But I happen to know Stalnaker is a spy
for North Korea, so Michelle said she wants to meet a spy
for North Korea tonight. Michelle said no such
thing. The faulty reasoner illegitimately assumed that what is
true of a person under one description will remain true when
said of that person under a second description even in this
context of indirect quotation. What was true of the person
when described as “her new neighbor Stalnaker” is that
Michelle said she wants to meet him, but it wasn’t legitimate
for me to assume this is true of the same person when he is
described as “a spy for North Korea.”
Extensional contexts are those in which it is legitimate to
substitute equals for equals with no worry. But any context in
which this substitution of co-referring terms is illegitimate
is called an intensional context. Intensional contexts are
produced by quotation, modality, and intentionality
(propositional attitudes). Intensionality is failure of
extensionality, thus the name “intensional fallacy”.
An invalid inference. An argument can be assessed by
deductive standards to see if the conclusion would have to be
true if the premises were to be true. If the argument
cannot meet this standard, it is invalid. An
argument is invalid only if it is not an instance of any valid
argument form. The fallacy of invalid reasoning is a
If it's raining, then there are clouds in the
sky. It's not raining. Therefore, there are no clouds in the
sky.This invalid argument is an instance of denying
the antecedent. Any invalid inference that is also
inductively very weak is a non
If an arguer argues for a certain conclusion while falsely
believing or suggesting that a different conclusion is
established, one for which the first conclusion is irrelevant,
then the arguer commits the fallacy of irrelevant conclusion.
In court, Thompson testifies that the defendant
is a honorable person, who wouldn't harm a flea. The defense
attorney rises to say that Thompson's testimony shows his
client was not near the murder scene.The
testimony of Thompson may be relevant to a request for
leniency, but it is irrelevant to any claim about the
defendant not being near the murder scene.
This fallacy is a kind of non
sequitur in which the premises are wholly irrelevant to
drawing the conclusion.
Lao Tze Beer is the top selling beer in
Thailand. So, it will be the best beer for
The is-ought fallacy occurs when a conclusion expressing
what ought to be so is inferred from premises expressing only
what is so, in which it is supposed that no implicit or
explicit ought-premises are need. There is controversy in the
philosophical literature regarding whether this type of
inference is always fallacious.
He's torturing the cat.This argument clearly would not commit the
fallacy if there were an implicit premise indicating that he
is a person and persons shouldn't torture other beings.
So, he shouldn't do
Jumping to Conclusions
When we draw a conclusion without taking the trouble to
acquire all the relevant evidence, we commit the fallacy of
jumping to conclusions, provided there was sufficient time to
assess that extra evidence, and that the effort to get the
evidence isn't prohibitive.
This car is really cheap. I'll buy it.
Hold on. Before concluding that you should buy
it, you ought to have someone check its operating condition,
or else you should make sure you get a guarantee about the
car's being in working order. And, if you stop to think about
it, there may be other factors you should consider before
making the purchase. Are size or appearance or gas mileage
or downplaying a point that is a crucial step in a piece of
reasoning is an example of the Fallacy of Lack of
Proportion. It's a mistake of not adopting the proper
perspective. An extreme form of downplaying occurs in
of Suppressed Evidence.
Chandra just overheard the terrorists say that they are
about to plant the bomb in the basement of the courthouse,
after which they'll drive to the airport and get away.
But they won't be taking along their cat. The poor
cat. The first thing that Chandra and I should do is
to call the Humane Society and check the "Cat Wanted"
section of the local newspapers to see if we can find a
proper home for the cat.
If we improperly reject a vague claim because it's not as
precise as we'd like, then we commit the line-drawing fallacy.
Being vague is not being hopelessly vague. Also called the
Bald Man Fallacy, the Fallacy of the Heap and the Sorites
Dwayne can never grow bald. Dwayne isn't bald
now. Don't you agree that if he loses one hair, that won't
make him go from not bald to bald? And if he loses one hair
after that, then this one loss, too, won't make him go from
not bald to bald. Therefore, no matter how much hair he
loses, he can't become bald.
Loaded language is emotive terminology that expresses value
judgments. When used in what appears to be an objective
description, the terminology unfortunately can cause the
listener to adopt those values when in fact no good reason has
been given for doing so. Also called Prejudicial Language.
[News broadcast] In today's top stories, Senator
Smith carelessly cast the deciding vote today to pass both
the budget bill and the trailer bill to fund yet another
excessive watchdog committee over coastal
development.This broadcast is an editorial posing
as a news report.
A fallacy of reasoning that depends on intentionally saying
something that is known to be false. If the lying occurs in an
argument's premise, then it is an example of the fallacy of questionable
Abraham Lincoln, Theodore Roosevelt, and John
Kennedy were assassinated.Roosevelt was never
They were U.S.
Therefore, at least three U.S. presidents
have been assassinated.
When the fallacy of jumping
to conclusions is committed due to a special emphasis on
an anecdote or other piece of evidence, then the fallacy of
misleading vividness has occurred.
Yes, I read the side of the cigarette pack about
smoking being harmful to your health. That's the Surgeon
General's opinion, him and all his statistics. But let me
tell you about my uncle. Uncle Harry has smoked cigarettes
for forty years now and he's never been sick a day in his
life. He even won a ski race at Lake Tahoe in his age group
last year. You should have seen him zip down the mountain.
He smoked a cigarette during the award ceremony, and he had
a broad smile on his face. I was really proud. I can still
remember the cheering. Cigarette smoking can't be as harmful
as people say.The vivid anecdote is the story
about Uncle Harry. Too much emphasis is placed on it and not
enough on the statistics from the Surgeon General.
Mistakenly supposing that something is a concrete object
with independent existence, when it's not.
There are two footballs lying on the floor of an
otherwise empty room. When asked to count all the objects in
the room, John says there are three: the two balls plus the
group of two.
John mistakenly supposed a group or set of
concrete objects is also a concrete object.
If the misrepresentation occurs on purpose, then it is an
example of lying.
If the misrepresentation occurs during a debate in which there
is misrepresentation of the opponent's claim, then it would be
the cause of a straw
This is the error of treating modal conditionals as if the
modality applies only to the consequent of the conditional.
"The" modal fallacy is the most well known of the infinitely
many errors involving modal concepts, concepts such as
necessity, possibility and so forth. A conditional is an
if-then proposition. The consequent is the then-part, and the
antecedent is the if-part.
If a proposition is true, then it can not be
false. But if a proposition can not be false, then it is not
only true but necessarily true. Therefore, if a proposition
is true, then it's necessarily true.The
acceptable interpretation of the first premise, requires the
modality to apply to the entire conditional in the sense that
it really means "It's not possible that if a proposition is
true, then it's false." However, the entire inference works
only if the first premise is miscontrued as saying "If a
proposition is true, then it is necessary that it's not
To see that the misconstrual is unacceptable, pick a
proposition such as "It's raining in Detroit." Let's suppose
it actually is raining in Detroit. So, the antecedent of the
misconstrual is true, but the consequent isn't, because it
says "It is necessary that 'it's raining in Detroit' is not
false." This isn't necessary, is it?
On a broad interpretation of the fallacy, it is said to
apply to any attempt to argue from an "is" to an "ought," that
is, to argue directly from a list of facts to a claim about
what ought to be done.
Owners of financially successful companies are
more successful than poor people in the competition for
wealth, power and social status. Therefore, these owners are
morally better than poor people, and the poor deserve to be
The fallacy would also occur if one argued from the natural
to the moral as follows: since women are naturally capable of
bearing and nursing children, they ought to be the primary
caregivers of children. There is considerable disagreement
among philosophers regarding what sorts of arguments the term
"Naturalistic Fallacy" applies to, and even whether it is a
fallacy at all.
Neglecting a Common Cause
This error is a kind of ad
hoc rescue of one's generalization in which the reasoner
re-characterizes the situation solely in order to escape
refutation of the generalization.
Smith: All Scotsmen are loyal and brave.
Jones: But McDougal over there is a Scotsman, and
he was arrested by his commanding officer for running from
Smith: Well, if that's right, it just shows that
McDougal wasn't a TRUE Scotsman.
Causa Pro Causa
This label is Latin for mistaking the "non-cause for the
cause." See False
When a conclusion is supported only by extremely weak
reasons or by irrelevant reasons, the argument is fallacious
and is said to be a non sequitur. However, we usually apply
the term only when we cannot think of how to label the
argument with a more specific fallacy name. Any deductively invalid
inference is a non sequitur if it also very weak when
assessed by inductive
Nuclear disarmament is a risk, but everything in
life involves a risk. Every time you drive in a car you are
taking a risk. If you're willing to drive in a car, you
should be willing to have disarmament.
The following is not an example: "If she committed the
murder, then there'd be his blood stains on her hands. His
blood stains are on her hands. So, she committed the
murder." This deductively invalid argument commits the fallacy
the consequent, but it isn't a non sequitur because it has
significant inductive strength.
You oversimplify when you cover up relevant complexities or
make a complicated problem appear to be too much simpler than
it really is.
President Bush wants our country to trade with
Fidel Castro's Communist Cuba. I say there should be a trade
embargo against Cuba. The issue in our election is Cuban
trade, and if you are against it, then you should vote for
me for president. Whom to vote for should be
decided by considering quite a number of issues in addition to
Cuban trade. When an oversimplification results in falsely
implying that a minor causal factor is the major one, then the
reasoning also commits the false
The pathetic fallacy is a mistaken belief due to
attributing peculiarly human qualities to inanimate objects
(but not to animals). The fallacy is caused by
Aargh, it won't start again. This old car always
breaks down on days when I have a job interview. It must be
afraid that if I get a new job, then I'll be able to afford
a replacement, so it doesn't want me to get to my interview
Some people try to win their arguments by getting you to
accept their faulty definition. If you buy into their
definition, they've practically persuaded you
already. Same as the Definist
the Well when presenting a definition would be an example
of a using persuasive definition.
Let's define a Democrat as a leftist who desires
to overtax the corporations and abolish freedom in the
If you remark that a proposal or claim should be rejected
solely because it doesn't solve the problem perfectly, in
cases where perfection isn't really required, then you've
committed the perfectionist fallacy.
You said hiring a house cleaner would solve our cleaning
problems because we both have full-time jobs. Now, look what
happened. Every week she unplugs the toaster oven and leaves
it that way. I should never have listened to you about
hiring a house cleaner.
Poisoning the well is a preemptive attack on a person in
order to discredit their testimony or argument in advance of
their giving it. A person who thereby becomes unreceptive to
the testimony reasons fallaciously and has become a victim of
the poisoner. This is a kind of ad
[Prosecuting attorney in court] When is the
defense attorney planning to call that twice-convicted child
molester, David Barnington, to the stand? OK, I'll rephrase
that. When is the defense attorney planning to call David
Barnington to the stand?
Suppose we notice that an event of kind A is followed in
time by an event of kind B, and then hastily leap to the
conclusion that A caused B. If so, we commit the post hoc
fallacy. Correlations are often good evidence of causal
connection, so the fallacy occurs only when the leap to the
causal conclusion is done "hastily." The Latin term for the
fallacy is post hoc, ergo propter hoc ("After this, therefore
because of this"). It is a kind of false
I ate in that Ethiopian restaurant three days
ago and now I've just gotten food poisoning. The only other
time I've eaten in an Ethiopian restaurant I also got food
poisoning, but that time I got sick a week later. My eating
in those kinds of restaurants is causing my food
poisoning.Your background knowledge should tell
you this is unlikely because the effects of food poisoning are
felt soon after the food is eaten. Before believing your
illness was caused by eating in an Ethiopian restaurant, you'd
need to rule out other possibilities, such as your illness
being caused by what you ate a few hours before the onset of
If you have sufficient background information to know that
a premise is questionable or unlikely to be acceptable, then
you commit this fallacy if you accept an argument based on
that premise. This broad category of fallacies of
argumentation includes appeal
to authority, false
the deck, straw
evidence, and many others.
We quibble when we complain about a minor point and falsely
believe that this complaint somehow undermines the main point.
To avoid this error, the logical reasoner will not make a
mountain out of a mole hill nor take people too literally.
I've found typographical errors in your poem, so
the poem is neither inspired nor perceptive.
Quoting out of Context
If you quote someone, but select the quotation so that
essential context is not available and therefore the person's
views are distorted, then you've quoted "out of context."
Quoting out of context in an argument creates a straw
Smith: I've been reading about a peculiar
game in this article about vegetarianism. When we play this
game, we lean out from a fourth-story window and drop down
strings containing "Free food" signs on the end in order to
hook unsuspecting passers-by. It's really outrageous, isn't
it? Yet isn't that precisely what sports fishermen do for
entertainment from their fishing boats? The article says
it's time we put an end to sport fishing.
quotation is fallacious because it makes Smith appear to
advocate this immoral activity when the context makes it clear
that he doesn't.
Jones: Let me quote Smith for you. He says
"We...hook unsuspecting passers-by." What sort of moral
monster is this man Smith?
We rationalize when we inauthentically offer reasons to
support our claim. We are rationalizing when we give someone a
reason to justify our action even though we know this reason
is not really our own reason for our action, usually because
the offered reason will sound better to the audience than our
"I bought the matzo bread from Kroger's
Supermarket because it is the cheapest brand and I wanted to
save money," says Alex [who knows he bought the bread from
Kroger's Supermarket only because his girlfriend works
A red herring is a smelly fish that would distract even a
bloodhound. It is also a digression that leads the reasoner
off the track of considering only relevant information.
Will the new tax in Senate Bill 47 unfairly hurt
business? One of the provisions of the bill is that the tax
is higher for large employers (fifty or more employees) as
opposed to small employers (six to forty-nine employees). To
decide on the fairness of the bill, we must first determine
whether employees who work for large employers have better
working conditions than employees who work for small
employers. Bringing up the issue of working
conditions is the red herring.
Refutation by Caricature
This fallacy occurs when regression to the mean is mistaken
for a sign of a causal connection. Also called the Regressive
Fallacy. It is a kind of false
You are investigating the average heights of
groups of Americans. You sample some people from Chicago and
determine their average height. You have the figure for the
mean height of Americans and notice that your Chicagoans
have an average height that differs from this mean. Your
second sample of the same size is from people from Miami.
When you find that this group's average height is closer to
the American mean height [as it is very likely to be due to
common statistical regression to the mean], you falsely
conclude that there must be something causing Miamians
rather than Chicagoans be more like the average
American.There is most probably nothing causing
Miamians to be more like the average American; but rather what
is happening is that averages are regressing to the mean.
Drawing an improper conclusion about causation due to a
causal assumption that reverses cause and effect. A kind of false
All the corporate officers of Miami Electronics
and Power have big boats. If you're ever going to become an
officer of MEP, you'd better get a bigger boat.
The false assumption here is that having a big
boat helps cause you to be an officer in MEP, whereas the
reverse is true. Being an officer causes you to have the high
income that enables you to purchase a big boat.
If you unfairly blame an unpopular person or group of
people for a problem, then you are scapegoating. This is a
kind of fallacy of appeal
Augurs were official diviners of ancient Rome.
During the pre-Christian period, when Christians were
unpopular, an augur would make a prediction for the emperor
about, say, whether a military attack would have a
successful outcome. If the prediction failed to come true,
the augur would not admit failure but instead would blame
nearby Christians for their evil influence on his divining
powers. The elimination of these Christians, the augur would
claim, could restore his divining powers and help the
emperor. By using this reasoning tactic, the augur was
scapegoating the Christians.
If you suppose that terrorizing your opponent is giving him
a reason for believing that you are correct, you are using a
scare tactic and reasoning fallaciously.
David: My father owns the department
store that gives your newspaper fifteen percent of all its
advertising revenue, so I'm sure you won't want to publish
any story of my arrest for spray painting the college.
given the editor a financial reason not to publish, but he has
not given a relevant reason why the story is not newsworthy.
David's tactics are scaring the editor, but it's the editor
who commits the scare tactic fallacy, not David. David has
merely used a scare tactic. This fallacy's name emphasizes the
cause of the fallacy rather than the error itself. See also
the related fallacy of appeal
Newspaper editor: Yes, David, I see your point.
The story really isn't newsworthy.
The scope fallacy is caused by improperly changing or
misrepresenting the scope of a phrase.
Every concerned citizen who believes that
someone living in the US is a terrorist should make a report
to the authorities. But Shelley told me herself that she
believes there are terrorists living in the US, yet she
hasn't made any reports. So, she must not be a concerned
citizen. The first sentence has ambiguous scope.
It was probably originally meant in this sense: Every
concerned citizen who believes (of someone that this person is
living in the US and is a terrorist) should make a report to
the authorities. But the speaker is clearly taking the
sentence in its other, less plausible sense: Every concerned
citizen who believes (that there is someone or other living in
the US who is a terrorist) should make a report to the
authorities. Scope fallacies usually are amphibolies.
Accident, two versions of the fallacy.
Improperly focusing attention on certain things and
Father: Justine, how was your school day
today? Another C on the history test like last
Justine: Dad, I got an A- on my history test
today. Isn't that great? Only one student got an
Father: I see you weren't the one with the
A. And what about the math quiz?
think I did OK, better than last time.
you really did well, you'd be sure. What I'm sure of
is that today was a pretty bad day for you.
The pessimist who pays attention to all the bad news and
ignores the good news thereby commits the fallacy of selective
attention. The remedy for this fallacy is to pay
attention to all the relevant evidence. The most common
examples of selective attention are the fallacy of Suppressed
Evidence and the fallacy of Confirmation
Bias. See also the Sharpshooter's
The fallacy occurs when the act of prophesying will itself
produce the effect that is prophesied, but the reasoner
doesn't recognize this and believes the prophesy is a
A group of students are selected to be
interviewed individually by the teacher. Each selected
student is told that the teacher has predicted they will do
significantly better in their future school work. Actually,
though, the teacher has no special information about the
students and has picked the group at random. If the students
believe this prediction about themselves, then, given human
psychology, it is likely that they will do better merely
because of the teacher's making the prediction.
The prediction will fulfill itself, so to speak,
and the students commit the fallacy.
This fallacy can be dangerous in an atmosphere of potential
war between nations when the leader of a nation predicts that
their nation will go to war against their enemy. This
prediction could very well precipitate an enemy attack because
the enemy calculates that if war is inevitable then it is to
their military advantage not to get caught by surprise.
The sharpshooter's fallacy gets its name from someone
shooting a rifle at the side of the barn and then going over
and drawing a target and bulls eye concentrically around the
bullet hole. The fallacy is caused by overemphasizing
random results or making selective use of coincidence. See the
Fallacy of Selective
Psychic Sarah makes twenty-six predictions about what
will happen next year. When one, but only one, of the
predictions comes true, she says, "Aha! I can see into
This error occurs when the issue is not treated fairly
because of misrepresenting the evidence by, say, suppressing
part of it, or misconstruing some of it, or simply lying. See
the following fallacies: Lying,
out of Context, Straw
Suppose someone claims that a first step (in a chain of
causes and effects, or a chain of reasoning) will probably
lead to a second step that in turn will probably lead to
another step and so on until a final step ends in trouble. If
the likelihood of the trouble occurring is exaggerated, the
slippery slope fallacy is committed.
Mom: Those look like bags under your
eyes. Are you getting enough sleep?
The form of a slippery slope
fallacy looks like this:
Jeff: I had a test and stayed up late studying.
Mom: You didn't take any drugs, did you?
Jeff: Just caffeine in my coffee, like I always
Mom: Jeff! You know what happens when people take
drugs! Pretty soon the caffeine won't be strong enough. Then
you will take something stronger, maybe someone's diet pill.
Then, something even stronger. Eventually, you will be doing
cocaine. Then you will be a crack addict! So, don't drink
A leads to B. Think
of the sequence A, B, C, D, ..., Z as a sequence of closely
stacked dominoes. The key claim in the fallacy is that pushing
over the first one will start a chain reaction of falling
dominoes, each one triggering the next. But the analyst asks
how likely is it really that pushing the first will lead to
the fall of the last? For example, if A leads to B with a
probability of 80 percent, and B leads to C with a probability
of 80 percent, and C leads to D with a probability of 80
percent, is it likely that A will eventually lead to D? No,
not at all; there is about a 50- 50 chance. The proper
analysis of a slippery slope argument depends on sensitivity
to such probabilistic calculations. Regarding terminology, if
the chain of reasoning A, B, C, D, ..., Z is about causes,
then the fallacy is called the Domino Fallacy.
B leads to C.
C leads to
Z leads to HELL.
We don't want to go to
So, don't take that first step A.
This is the fallacy of using too small a sample. If the
sample is too small to provide a representative sample of the
population, and if we have the background information to know
that there is this problem with sample size, yet we still
accept the generalization upon the sample results, then we
commit the fallacy. This fallacy is the fallacy of hasty
generalization, but it emphasizes statistical sampling
I've eaten in restaurants twice in my life, and
both times I've gotten sick. I've learned one thing from
these experiences: restaurants make me sick. How
big a sample do you need to avoid the fallacy? Relying on
background knowledge about a population's lack of diversity
can reduce the sample size needed for the generalization. With
a completely homogeneous population, a sample of one is large
enough to be representative of the population; if we've seen
one electron, we've seen them all. However, eating in one
restaurant is not like eating in any restaurant, so far as
getting sick is concerned. We cannot place a specific number
on sample size below which the fallacy is produced unless we
know about homogeneity of the population and the margin of
error and the confidence level.
A smear tactic is an unfair characterization either of the
opponent or the opponent's position or argument. Smearing the
opponent causes an ad
hominem fallacy. Smearing the opponent's argument causes a
This fallacy occurs by offering too many details in order
either to obscure the point or to cover-up counter-evidence.
In the latter case it would be an example of the fallacy of suppressed
evidence. If you produce a smokescreen by bringing up an
irrelevant issue, then you produce a red
herring fallacy. Sometimes called clouding the issue.
Senator, wait before you vote on Senate Bill 88.
Do you realize that Delaware passed a bill on the same
subject in 1932, but it was ruled unconstitutional for these
twenty reasons. Let me list them here.... Also, before you
vote on SB 88 you need to know that .... And so
on.There is no recipe to follow in distinguishing
smokescreens from reasonable appeals to caution and care.
Special pleading is a form of inconsistency in which the
reasoner doesn't apply his or her principles consistently. It
is the fallacy of applying a general principle to various
situations but not applying it to a special situation that
interests the arguer even though the general principle
properly applies to that special situation, too.
Everyone has a duty to help the police do their
job, no matter who the suspect is. That is why we must
support investigations into corruption in the police
department. No person is above the law. Of course, if the
police come knocking on my door to ask about my neighbors
and the robberies in our building, I know nothing. I'm not
about to rat on anybody.In our example, the
principle of helping the police is applied to investigations
of police officers but not to one's neighbors.
Drawing an overly specific conclusion from the evidence. A
kind of jumping
The trigonometry calculation came out to
35,005.6833 feet, so that's how wide the cloud is up
Evidence and Slanting.
Using stereotypes as if they are accurate generalizations
for the whole group is an error in reasoning. Stereotypes are
general beliefs we use to categorize people, objects, and
events; but these beliefs are overstatements that shouldn't be
taken literally. For example, consider the stereotype "She’s
Mexican, so she’s going to be late." This conveys a mistaken
impression of all Mexicans. On the other hand, even though
most Mexicans are punctual, a German is more apt to be
punctual than a Mexican, and this fact is said to be the
"kernel of truth" in the stereotype. The danger in our using
stereotypes is that speakers or listeners will not realize
that even the best stereotypes are accurate only when taken
probabilistically. As a consequence, the use of stereotypes
can breed racism, sexism, and other forms of bigotry.
German people aren't good at dancing our sambas.
She's German. So, she's not going to be any good at dancing
our sambas.This argument is deductively valid,
but it's unsound
because it rests on a false, stereotypical premise. The grain
of truth in the stereotype is that the average German doesn't
dance sambas as well as the average South American, but to
overgeneralize and presume that ALL Germans are poor samba
dancers compared to South Americans is a mistake called
You commit the straw man fallacy whenever you attribute an
easily refuted position to your opponent, one that the
opponent wouldn't endorse, and then proceed to attack the
easily refuted position believing you have undermined the
opponent's actual position. If the misrepresentation is on
purpose, then the straw man fallacy is caused by lying.
Example (a debate before the city council):
Opponent: Because of the killing and
suffering of Indians that followed Columbus's discovery of
America, the City of Berkeley should declare that Columbus
Day will no longer be observed in our city.
The speaker has
twisted what his opponent said; the opponent never said, nor
even indirectly suggested, that everybody who ever came to
America from another country somehow oppressed the Indians.
Speaker: This is ridiculous, fellow members of the
city council. It's not true that everybody who ever came to
America from another country somehow oppressed the Indians.
I say we should continue to observe Columbus Day, and vote
down this resolution that will make the City of Berkeley the
laughing stock of the nation.
Unfortunately the style with which an argument is presented
is sometimes taken as adding to the substance or strength of
You've just been told by the salesperson that
the new Maytag is an excellent washing machine because it
has a double washing cycle. If you were to notice that the
salesperson smiled at you and was well dressed, this
wouldn't add to the quality of the original argument, but
unfortunately it does for those who are influenced by style
over substance, as most of us are.
The subjectivist fallacy occurs when it is mistakenly
supposed that a good reason to reject a claim is that truth on
the matter is relative to the person or group.
Justine has just given Jake her reasons for
believing that the Devil is an imaginary evil person. Jake,
not wanting to accept her conclusion, responds with, "That's
perhaps true for you, but it's not true for me."
Reasoning deserves to be called superstitious if it is
based on reasons that are well known to be unacceptable,
usually due to unreasonable fear of the unknown, trust in
magic, or an obviously false idea of what can cause what. A
belief produced by superstitious reasoning is called a
superstition. The fallacy is an instance of the False
I never walk under ladders; it's bad luck.
It may be a good idea not to walk under ladders,
but a proper reason to believe this is that workers on ladders
occasionally drop things, and that ladders might have dripping
wet paint that could damage your clothes. An improper reason
for not walking under ladders is that it is bad luck to do so.
Intentionally failing to use information suspected of being
relevant and significant is committing the fallacy of
suppressed evidence. This fallacy usually occurs when the
information counts against one's own conclusion. Perhaps the
arguer is not mentioning that experts have recently objected
to one of his premises. The fallacy is a kind of fallacy of Selective
Buying the Cray Mac 11 computer for our company
was the right thing to do. It meets our company's needs; it
runs the programs we want it to run; it will be delivered
quickly; and it costs much less than what we had budgeted.
This appears to be a good argument, but you'd
change your assessment of the argument if you learned the
speaker has intentionally suppressed the relevant evidence
that the company's Cray Mac 11 was purchased from his
brother-in-law at a 30 percent higher price than it could have
been purchased elsewhere, and if you learned that a recent
unbiased analysis of ten comparable computers placed the Cray
Mac 11 near the bottom of the list.
If the relevant information is not intentionally suppressed
by rather inadvertently overlooked, the fallacy of suppressed
evidence also is said to occur, although the fallacy's name is
misleading in this case. The fallacy is also called the
Fallacy of Incomplete
Evidence and Cherry-Picking
the Evidence. See also Slanting.
Syllogistic fallacies are kinds of invalid categorical
syllogisms. This list contains the fallacy of undistributed
middle and the fallacy of four
terms, and a few others though there are a great many such
If you interpret a merely token gesture as an adequate
substitute for the real thing, you've been taken in by
How can you call our organization racist? After
all, our receptionist is African American. If you
accept this line of reasoning, you have been taken in by
If you say or imply that a practice must be OK today simply
because it has been the apparently wise practice in the past,
you commit the fallacy of traditional wisdom. Procedures that
are being practiced and that have a tradition of being
practiced might or might not be able to be given a good
justification, but merely saying that they have been practiced
in the past is not always good enough, in which case the
fallacy is committed. Also called argumentum consensus gentium
when the traditional wisdom is that of nations.
Of course we should buy IBM's computer whenever
we need new computers. We have been buying IBM as far back
as anyone can remember. The "of course" is the
problem. The traditional wisdom of IBM being the right buy is
some reason to buy IBM next time, but it's not a good enough
reason in a climate of changing products, so the "of course"
indicates that the fallacy of traditional wisdom has occurred.
The fallacy of tu quoque is committed if we conclude that
someone's argument not to perform some act must be faulty
because the arguer himself or herself has performed it.
Similarly, when we point out that the arguer doesn't practice
what he preaches, we may be therefore suppose that there must
be an error in the preaching, but we are reasoning
fallaciously and creating a tu quoque. This is a kind of ad
You say I shouldn't become an alcoholic because
it will hurt me and my family, yet you yourself are an
alcoholic, so your argument can't be worth listening to.
Discovering that a speaker is a hypocrite is a
reason to be suspicious of the speaker's reasoning, but it is
not a sufficient reason to discount it.
Wrongs Make a Right
When you defend your wrong action as being right because
someone previously has acted wrongly, you commit the fallacy
called "two wrongs make a right." This is a kind of ad
Oops, no paper this morning. Somebody in our
apartment building probably stole my newspaper. So, that
makes it OK for me to steal one from my neighbor's doormat
while nobody else is out here in the hallway.
In syllogistic logic, failing to distribute the middle term
over at least one of the other terms is the fallacy of
undistributed middle. Also called the fallacy of
All collies are animals.The
middle term ("animals") is in the predicate of both universal
affirmative premises and therefore is undistributed. This
formal fallacy has the logical form: All C are A. All D are A.
Therefore, all C are D.
All dogs are
Therefore, all collies are dogs.
This error in explanation occurs when the explanation
contains a claim that is not falsifiable, because there is no
way to check on the claim. That is, there would be no
way to show the claim to be false if it were
He lied because he's possessed by
demons.This could be the correct explanation of
his lying, but there's no way to check on whether it's
correct. You can check whether he's twitching and
moaning, but this won't be evidence about whether a
supernatural force is controlling his body. The claim
that he's possessed can't be verified if it's true, and it
can't be falsified if it's false. So, the claim is too
odd to be relied upon for an explanation of his lying.
Relying on the claim is an instance of fallacious
If the means of collecting the sample from the population
are likely to produce a sample that is unrepresentative of the
population, then a generalization upon the sample data is an
inference committing the fallacy of unrepresentative sample. A
kind of hasty
generalization. When some of the statistical evidence is
expected to be relevant to the results but is hidden or
overlooked, the fallacy is called suppressed evidence.
The two men in the matching green suits that I
met at the Star Trek Convention in Las Vegas had a terrible
fear of cats. I remember their saying they were from
Delaware. I've never met anyone else from Delaware, so I
suppose everyone there has a terrible fear of
cats.Most people's background information is
sufficient to tell them that people at this sort of convention
are unlikely to be representative, that is, typical members of
Large samples can be unrepresentative, too.
We've polled over 400,000 Southern Baptists and
asked them whether the best religion in the world is
Southern Baptist. We have over 99% agreement, which proves
our point about which religion is best. Getting a
larger sample size does not overcome sampling bias.
I've got my mind made up, so don't confuse me with the
facts. This is usually a case of the Traditional
Of course she's made a mistake. We've always had
meat and potatoes for dinner, and our ancestors have always
had meat and potatoes for dinner, and so nobody knows what
they're talking about when they start saying meat and
potatoes are bad for us.
A reasoner who suggests that a claim is true, or false,
merely because he or she strongly hopes it is, is committing
the fallacy of wishful thinking. Wishing something is true is
not a relevant reason for claiming that it is actually true.
There's got to be an error here in the history
book. It says Thomas Jefferson had slaves. He was our best
president, and a good president would never do such a thing.
That would be awful.
7. References and Further
Eemeren, Frans H. van, R. F. Grootendorst, F. S. Henkemans,
J. A. Blair, R. H. Johnson, E. C. W. Krabbe, C. W. Plantin, D.
N. Walton, C. A. Willard, J. A. Woods, and D. F. Zarefsky,
1996. Fundamentals of Argumentation Theory: A Handbook of
Historical Backgrounds and Contemporary Developments.
Mahwah, New Jersey, Lawrence Erlbaum Associates, Publishers.
Fischer, David H., 1970. Historian's Fallacies. New
York, Harper & Row.
Huff, Darrell, 1954. How to Lie with Statistics. New
York, W. W. Norton.
Groarke, Leo and C. Tindale, 2003. Good Reasoning
Matters! 3rd edition, Toronto, Oxford University Press.
Hamblin, Charles L., 1970. Fallacies. London,
Hansen, Has V. and R. C. Pinto., 1995. Fallacies:
Classical and Contemporary Readings. University Park,
Pennsylvania State University Press.
Levi, D. S., 1994. "Begging What is at Issue in the
Argument," Argumentation, 8, 265-282.
Walton, Douglas N., 1989. Informal Logic: A Handbook for
Critical Argumentation. Cambridge, Cambridge University
Walton, Douglas N., 1995. A Pragmatic Theory of
Fallacy. Tuscaloosa, University of Alabama Press.
Walton, Douglas N., 1997. Appeal to Expert Opinion:
Arguments from Authority. University Park, Pennsylvania
State University Press.
Whately, Richard, 1836. Elements of Logic. New York,
Woods, John and D. N. Walton, 1989. Fallacies: Selected
Papers 1972-1982. Dordrecht, Holland, Foris.
Research on the fallacies of informal logic is
regularly published in the following journals:
Argumentation, Argumentation and Advocacy,
Informal Logic, Philosophy and Rhetoric, and