Logic is pretty well understood by now, and the rules aren't all that hard. To start the ball rolling, I dragged out my old copy of
Copiīs Introduction to Logic, and turned to the section on informal fallacies.
A fallacy is (in this context) a type of argument that may be psychologically persuasive, but incorrect. Obviously there are an infinite number of incorrect arguments, but there are a number of classically recognized ones that recur often. These should be recognized and arguments based on them discarded. To *very broadly* summarize Copi's list:
1. fallacies of relevance:
the first set of fallacies are those in
which the argument used is logically irrelevant to the conclusion.
appeal to force: an argument through implied (or overt) threat. "You
should agree with me because I've got a gun in my pocket". "People
who believe so and so should be taken out and shot".
argumentum ad hominem (abusive): argument addressed against the
opponent rather than the issue, for instance making the point that
one's opponent is a communist in a discussion on computer science.
argumentum ad hominem (circumstantial): arguing that one's opponent,
because of their circumstances, should hold a given view. For
instance, arguing that a person must be against birth control because
they are Catholic.
argument from ignorance: the argument that something must be true
simply because it hasn't been proved to be false, or vice versa.
appeal to pity: appealing to pity in support of a conclusion, where
the conclusion is one of fact and not of sentiment, e.g. referring to a
murder suspect's dependent family.
argumentum ad populum: attempting to win popular support for a
conclusion by arousing emotions and enthusiasms, rather than by
appeal to relevant facts. Presidential candidates hanging out at flag
factories, or riding tanks, for instance.
appeal to authority: citing as evidence for one's conclusion the
support of someone else for that conclusion. This is valid if not
conclusive if the cited authority is genuinely a studied expert in the
area being discussed, but is invalid generally.
accident: applying a general rule in a case where "accidental"
circumstances render that inapplicable. For instance, while generally
one should not exceed the speed limit, it is acceptable for emergency
vehicles to do so [assuming a reasonable speed limit, of course].
converse accident/hasty generalization: generalizing by observing
certain cases. For instance, considering the effect of alcohol only
on those who indulge to excess, and concluding that liquor is harmful
and should be outlawed.
false cause: arguing that one event causes another on the basis merely
that it occurs earlier, or more generally mistaking what is not the
cause of something as its cause. For instance, arguing that beating
of drums causes the sun to reappear after after an eclipse by citing
that every time drums have been so beaten the sun has reappeared.
begging the question: assuming the truth of one's proposal as a
premiss for the conclusion one is trying to prove.
complex question: arguing based on a response, or assumed response,
to a complex or "loaded" question, where no simple yes or no response
is reasonable -- "have you stopped beating your wife?" "will you vote
for the Republicans and prosperity?"
irrelevant conclusion: making a perfectly valid argument for a
conclusion other than the one at hand. In debating a housing bill a
speaker might validly argue that decent housing for all people is
desirable; this is irrelevant to whether or not that particular bill
will achieve that goal.
2. fallacies of ambiguity: these are arguments where certain words or
phrases have ambiguous meanings that are shifted or reinterpreted in
the course of the argument, rendering them fallacious.
equivocation: a fallacy arising from the ambiguity or multiplicity of
possible interpretations of a repeated word or phrase. "An elephant
is an animal, therefore a small elephant is a small animal".
amphiboly: an argument whose premisses contain statements with
grammatical constructions capable of being interpreted in more than
one way. Classical example: "if Croesus went to war with Cyrus, he
would destroy a mighty kingdom". Based on that advice Croesus went to
war with Cyrus and in so doing destroyed a mighty kingdom: his own.
accent: an argument based on a change in meaning through emphasis or
accent. "we should not speak ill of our friends", unaccented, may be
valid, while by accenting the last word the implication is added that
it may be acceptable to speak ill of others. Similarly, quoting or
emphasizing something out of context ("the captain was sober today").
composition: reasoning fallaciously from the attributes of the parts
of a whole to the attributes of the whole itself: "all of the parts of
this machine are light, therefore the machine itself is light". Or,
to infer that what may be said of a term distributively may be said of
the term collectively: "a bus uses more gasoline than a car, therefore
buses use more gasoline than cars".
division: the reverse of composition: reasoning from the attributes of
a whole to the attributes of its parts, or inferring that what may be
true of a term collectively is true distributively. "HP is a very
important company; I am an HP employee; therefore I am very
important"; "Dogs are frequently seen in the streets; Afghan hounds
are dogs; therefore Afghan hounds are frequently seen in the streets".
I hope the readership at large will find this brief summary useful in
analyzing invalid arguments, on their own part or that of others, and
so improve the overall rational quality of the various debates. I
have refrained here from referring to any specific arguments in any
ongoing debates [well, there was a reference to banning alcohol, but
that was Copi's example, not mine]
John W. Eshleman, Ed.D.
These are the basic logical fallacies, informal and formal. They are drawn from several sources. The informal fallacies are more likely to be useful, especially when you are debating with someone else.
If you learn the fallacies and become fluent in them you will be able to quickly spot the use of logical fallacies in someone else's reasoning, or even your own! Note: A fallacy is a deceptive, false, or misleading argument, notion, belief, etc.
The fallacies listed here are from a hypercard shareware stack that I have put together.
The basic format of this list (and of the stack), is (1) the formal name of the fallacy (usually its Latin name), followed by (2) a description of the fallacy.
LIST OF LOGICAL FALLACIES:
Description: A Fallacy of Ambiguity, where the ambiguity arises from
the emphasis (accent) placed on a word or phrase.
AFFIRMATION OF THE CONSEQUENT
Description: 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
Description: 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
Description: 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!)
ARGUMENTUM AD ANTIQUITAM
Description: A fallacy of asserting that something is right or good
simply because it is old; that is, because "that's the way it's always
ARGUMENTUM AD BACULUM
Description: 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 CRUMENAM
Description: Fallacy of believing that money is a criterion of
correctness; that those with more money are more likely to be
ARGUMENTUM AD HOMINEM
Description: 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 two basic types of ad hominem arguments: (1) abusive, and
ARGUMENTUM AD IGNORANTIAM
Description: 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:
1. P is true, because it has not been proven false.
2. P is false, because it has not been proven true.
ARGUMENTUM AD LAZARUM
Description: 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
ARGUMENTUM AD MISERICORDIAM
Description: An argument that appeals to pity for the sake of getting
a conclusion accepted.
ARGUMENTUM AD NAUSEUM
Description: 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 repitition in asserting a truth.
ARGUMENTUM AD NOVITAM
Description: 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
Description: 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.
ARGUMENTUM AD POPULUM
Description: 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. This
fallacy is also known as "Appeal to Tradition" Ad populum arguments
often occur in (1) propaganda, (2) demagoguery, and (3) advertising.
ARGUMENTUM AD VERECUNDIAM
Description: 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.
BEGGING THE QUESTION (CIRCULAR REASONING)
Description: 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." This Fallacy is also known by the Latin
Description: 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
Description: 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.
CONVERTING A CONDITIONAL
Description: If P then Q, therefore, if Q then P.
CUM HOC ERGO PROPTER HOC
Description: 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" fallacy.
DENIAL OF THE ANTECEDENT
Description: 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
Description: 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.
Description: 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 "unovocation," in which a word always carries the
same meaning through a given context.
FALLACY OF INTERROGATION
Description: The question asked has a presuppostion 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.
Description: 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.
HASTY GENERALIZATION (SECUNDUM QUID)
Description: 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.
Description: 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."
Description: 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.
PLURIUM INTERROGATIONUM-MANY QUESTIONS
Description: A demand for a simple answer to a complex question.
NON CAUSA PRO CAUSA
Description: 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.
Description: 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
Description: Same as "Begging the Question" The argument assumes
its conclusion is true but DOES NOT SHOW it to be true. Petitio principii
has two forms:
1. P is true, because P is true.
2. P is true, because A is true. And A is true because B is true.
And B is true because P is true.
POST HOC, ERGO PROPTER HOC
Description: 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.
Description: 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.
Description: 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
Description: 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".
SHIFTING THE BURDEN OF PROOF
Description: 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.
Description: 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.
Description: 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.
Description: Also known by the Latin term "DICTO SIMPLICITER",
a Sweeping Generalization 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.
TWO WRONGS MAKE A RIGHT (TU QUOQUE)
Description: Two wrongs never add up to a right; you cannot right
a wrong by applying yet another wrong. Such a fallacy is a
misplaced appeal to consistency. It is a fallacy because it makes
no attempt to deal with the subject under discussion.
Description: A syllogistic argument in which the middle term of
a categorical syllogism is not distributed in at least one of the
The following list of fallacies is taken from Irving M. Copi, Introduction to Logic (McMillan, 1978, 5th ed) Chap 3 "Informal Fallacies". Copi gives numerous examples of various fallacies, so those interested may wish to consult that work.
Fallacies of Relevance
1. Argumentum ad Baculum (appeal to force). The arguer appeals
to force or the threat of force to compel acceptance of the
2. Argumentum ad Hominem (abusive). "The phrase argumentum ad
hominem translates literally as 'argument directed to the
man.'" The abusive variety occurs when one attacks the other
person rather than the other persons argument.
3. Argumentum ad Hominem (circumstantial). In this case, one
tries to convince the opponent to agree to the conclusion
based on the opponents circumstances. For example (from
Copi), a hunter may claim an anti-hunter must say hunting is
acceptable since the anti-hunter is not a vegetarian.
4. Argumentum ad Ignoratiam (argument from ignorance). "The
fallacy of argumentum ad ignorantiam is illustrated by the
argument that there must be ghosts because no one has ever
been able to prove that there aren't any."
5. Argumentum ad Misericordiam (appeal to pity). The arguer
appeals to pity where the conclusion is a matter of reason and
not one of sentiment.
6. Argumentum ad Populam. "the attempt to win popular assent to
a conclusion by arousing the emotions and enthusiasms of the
multitude, rather than by appeal to the relevant facts."
7. Argumentum ad Verecundiam (appeal to authority). This is
especially the appeal to authority outside the field of that
authority's expertise. In the field of the authority's
expertise, "this method of argument is in many cases perfectly
legitimate, for the reference to an admitted authority in the
special field of that authority's competence may carry great
weight and constitute relevant evidence. ... Although it does
not prove the point, it certainly tends to support it."
8. Accident. "The fallacy of accident consists in applying a
general rule to a particular case whose 'accidental'
circumstances render the rule inapplicable."
9. Converse Accident (hasty generalization). Making a general
rule based on a few atypical cases.
10. False Cause. This is mistaking a event to be the cause of
some other event. For example, the sun rises every day after
my rooster crows; therefore, my rooster causes the sun to
11. Petitio Principii (begging the question). The conclusion of
an argument is contained in one of the premises assumed.
12. Complex Question. This is a question of the "Have you
stopped beating your wife?" variety.
13. Ignoratio Elenchi (irrelevant conclusion). An argument which
supports one conclusion is made to prove a different
conclusion. Copi's example is a legislator who, in
discussing a housing bill, argues only that decent housing
for all is desirable, rather than whether the bill in
question would achieve that goal.
Fallacies of Ambiguity.
1. Equivocation. Using the same word in two different senses.
2. Amphiboly. Arguing from premises which are ambiguous due to
their grammatical construction.
3. Accent. Stressing a word in a sentence which thereby changes the meaning.
4. Composition. Attributing to the whole the properties of the parts.
5. Division. Attributing to the parts the properties of the whole.
Copi also recommends the following: W.W. Fearnside and W.B. Holther,
Fallacy:The Counterfeit of Argument (Prentice-Hall, 1959); D.H.
Fischer, Historian's Fallacies (Harper & Row, 1970); and C.L.
Hamblin, Fallacies (Methuen, 1970).i
Ben Cushman & Reed College
Here is a list of everyday fallacies take from Peter A. Angeles Dictionary of Philosophy-- published by Barnes and Noble, copyright 1981. Great and useful book-- I strongly recommend picking up a copy. If these are not what you want, then you don't want fallacies.
Types of informal Fallacies. Sometimes semi-formal or quasi-formal
fallacies. The following is a list of 40 informal fallacies which is by
no means eshaustive. No attempt has been made to subsume them under
general categories such as Fallacies, Classification of Informal [which I
will also include].
1. Black-and-white fallacy. Arguing (a) with the use of sharp ("black-and-whi
te") distinctions despite any factual or theoretical support for them, or (b) b
y classifying any middle point between the extremes ("black-and-white") as one
of the extremes. Examples: "If he is an atheist then he is a decent person."
"He is either a conservative or a liberal." "He must not be peace-loving, since
he participated in picketing the American embassy."
2. Fallacy of argumentum ad baculum (argument from power or force.) The Latin
means "an argument according to the stick." "argument by means of the rod," "a
rgument using force." Arguing to support the acceptance of an argument by a th
reat, or use of force. Reasoning is replaced by force, which results in the ter
mination of logical argumentation, and elicits other kinds of behavior (such as
fear, anger, reciprocal use of force, etc.).
3. Fallacy of argumentum ad hominem (argument against the man) [a
personal favorite of mine]. The Latin means "argument to the man."
(a) Arguing against, or rejecting a person's views by attacking or
abusing his personality, character, motives, intentions,
qualifications, etc. as opposed to providing evidence why the views
are incorrect. Example: "What John said should not be believed
because he was a Nazi sympathizer." [Well, there goes Heidegger.]
4. Fallacy of argumentum ad ignorantiam (argument from ignorance).
The Latin means "argument to ignorance." (a) Arguing that
something is true because no one has proved it to be false, or (b)
arguing that something is false because no one has proved it to be
true. Examples: (a) Spirits exist since no one has as yet proved
that there are not any. (b) Spirits do not exist since no one has
as yet proved their existence. Also called the appeal to
ignorance: the lack of evidence (proof) for something is us ed to
support its truth.
5. Fallacy of argumentum ad misericordiam (argument to pity).
Arguing by appeal to pity in order to have some point accepted.
Example: "I've got to have at least a B in this course, Professor
Angeles. If I don't I won't stand a chance for medical school, and
this is my last semester at the university." Also called the
appeal to pity.
6. Fallacy of argumentum ad personam (appeal to personal interest).
Arguing by appealing to the personal likes (preferences,
prejudices, predispositions, etc.) of others in order to have an
7. Fallacy of argumentum ad populum (argument to the people). Also
the appeal to the gallery, appeal to the majority, appeal to what
is popular, appeal to popular prejudice, appeal to the multitude,
appeal to the mob instinct [appeal to the stupid, stinking masses].
Arguing in order to arouse an emotional, popular acceptance of an
idea without resorting to logical justification of the idea. An
appeal is made to such things as biases, prejudices, feelings,
enthusiasms, attitudes of the multitude in order to evoke assent
rather than to rationally support the idea.
8. Fallacy of argumentum ad verecundiam (argument to authority or
to veneration) [another of my personal favorites]. (a) appealing to
authority (including customs, traditions, institutions, etc.) in
order to gain acceptance of a point at issue and/or (b) appealing
to the feelings of reverence or respect we have of those in
authority, or who are famous. Example: "I believe that the
statement 'YOu cannot legislate morality' is true, because
President Eisenhower said it."
9. Fallacy of accent. Sometimes clasified as ambiguity of accent.
Arguing to conclusions from undue emphasis (accent, tone) upon
certain words or statements. Classified as a fallacy of ambiguity
whenever this anphasis creates an ambiguity or AMPHIBOLY in the
words or statements used in an argument. Example: "The queen
cannot but be praised." [also "We are free iff we could have done
otherwise."-- as this statement is used by incompatibilists about
free-will and determinism.]
10. Fallacy of accident. Also called by its Latin name a dicto
simpliciter ad dictum secundum quid. (a) Applying a general rule
or principle to a particular instance whose circumstances by
"accident" do not allow the proper application of that
generalization. Example: "It is a general truth that no one should
lie. Therefore, no one should lie if a murderer at the point of a
knife asks you for information you know would lead to a further
murder." (b) The error in arumentation of applying a general stat
ement to a situation to which it cannot, and was not necessarily
intended to, be applied.
11. Fallacy of ambiguity. An argument that has at least one
ambiguous word or statement from which a misleading or wrong
conclusion is drawn.
12. Fallacy of amphiboly. Arguing to conclusions from statements
that themselves are amphibolous-- ambiguous because of their syntax
(grammatical construction). Sometimes classified as a fallacy of
13. Fallacy of begging the question. (a) Arriving at a conclusion
from statements that themselves are questionable and have to be
proved but are assumed true. Example: The universe has a
beginning. Every thing that has a beginning has a beginner.
Therefore, the universe has a beginner called God. This assumes
(begs the question) that the universe does indeed have a beginning
and also that all things that have a beginning have a beginner.
(b) Assuming the conclusion as part of the conclusion in the
premises of an argument. Sometimes called circular reasoning,
vicious circularity, vicious circle fallacy. Example: "Everything
has a cause. The universe is a thing. Therefore, the universe is a
thing that has a cause." (c) Arguing in a circle. One statement is
supported by reference to another statement which is itself
supported by reference to the first statement [such as a
coherentist account of knowledge/truth]. Example: "Aristocracy is
the best form of government because the best form of government if
that which has strong aristocratic leadership."
14. Fallacy of complex question (or loaded question). (a) Asking
questions for which either a yes or no answer will incriminate the
respondent. The desired answer is already tacitly assumed in the
question and no qualification of the simple answer is allowed.
Example: "Have you discontinued the use of opiates?" (b) Asking
questions that are based on unstated attitudes or questionable (or
unjustified) assumptions. These questions are often asked
rhetorically of the respondent in such a way as to elicit an
agreement with those attitudes or assumptions from others.
Example: "How long are you going to put up with this brutality?"
15. Fallacy of composition. Arguing (a) that what is true of each
part of a whole is also (necessarily) true of the whole itself, or
(b) what is true of some parts is also (necessarily) true of the
whole itself. Example: "Each member (or some members) of the team
is married, therefore the team also has (must have) a wife." [A
less silly example-- you promise me that you will come to Portland
tomorrow, you also promise someone else that you will go to Detroit
tomorrow. Now, you ought to be in Portland tomorrow, and you ought
to be in Detroit tomorrow (because you ought to keep your
promises). However, it does not follow that you ought to be in
both Portland and Detroit tomorrow (because ought implies can).]
Inferring that a collection has a certain characteristic merely on
the basis that its parts have them erroneously proceeds from
regarding the collection DISTRIBUTIVELY to regarding it
16. Fallacy of consensus gentium. Arguing that an idea is true on
the basis (a) that the majority of people believe it and/or (b)
that it has been universally held by all men at all times.
Example: "God exists because all cultures have had some concept of
17. Fallacy of converse accident. Sometimes converse fallcy of
accident. Also called by its Latin name a dicto secumdum quid ad
dictum simpliciter. The error of generalizing from atypical or
exceptional instances. Example: "A shot of warm brandy each night
helps older people relax and sleep better. People in general ought
to drink warm brandy to relieve their tension and sleep better."
18. Fallacy of division. Arguing that what is true of a whole is
(a) also (necessarily) true of its parts and/or (b) also true of
some of its parts. Example: "The community of Pacific Palisades is
extremely wealthy. Therefore, every person living there is (must
be) extremely wealthy (or therefor A man, who lives there, must be
extremely wealthy." Inferring that the parts of a collection have
certain characteristic merely on the basis that their collection
has them erroneously proceeds from regarding t he collection
collectively to regarding it distributively.
19. Fallacy of equivocation. An argument in which a word is used
with one meaning in one part of the argument and with another
meaning in another part. A common example: "The end of a thing is
its perfection; death is the end of life; hence, death is the
perfection of life."
20. Fallacy of non causa pro causa. the LAtin may be translated as
"there is no cause of the sort that has been given as the cause."
(a) Believing that something is the cause of an effect when in
reality it is not. Example: "My incantations caused it to rain."
(b) Arguing so that a statement appears unacceptable because it
implies another statement that is false (but in reality does not).
21. Fallacy of post hoc ergo propter hoc. The Latin means "after
this therefore the consequence (effect) of this," or "after this
therefore because of this." Sometimes simply fallacy of false
cause. Concluding that one thing is the cause of another thing
because it precedes it in time. A confusion between the concept of
succession and that of causation. Example: "A black cat ran across
my path. Ten minutes later I was hit by a truck. Therefore, the
cat's running across my path was the cause of my being hit by a
22. Fallacy of hasy generalization.
Sometimes fallacy of hasty
induction. An error of reasoning whereby a general statement is
asserted (inferred) based on (a) limited information or (b)
inadequate evidence, or (c) an unrepresentative sampling.
23. Fallacy of ignoratio elenchi (irrelevant conclusion). An
argument that is irrelevant; that argues for something other than
that which is to be proved and thereby in no way refutes (or
supports) the points at issue. Example: A lawyer in defending his
alcoholic client who has murdered three people in a drunken spree
argues that alcoholism is a terrible disease and attempts should be
made to eliminate it. IGNORATIO ELENCHI is sometimes used as a
general name for all fallacies that are based on irrelev ancy (such
as ad baculum, ad hominem, as misericordiam, as populum, ad
verecundiam, consensus gentium, etc.)
24. Fallacy of inconsistency. Arguing from inconsistent
statements, or to conclusions that are inconsistent with the
premises. See fallacy of tu quoque below.
25. Fallacy of irrelevant purpose. Arguing against something on
the basis that it has not fulfilled its purpose (although in fact
that was not its intended purpose).
26 Fallacy of 'is' to 'ought.' Arguing from premises that have
only descriptive statements (is) to a conclusion that contains an
ought, or a should.
27. Fallacy of limited (or false) alternatives. The error of
insisting without full inquiry or evidence that the alternatives to
a course of action have been exhausted and/or are mutually
28. Fallacy of many questions. Sometimes fallacy of the false
question. Asking a question for which a single and simple answer
is demanded yet the question (a) requires a series of answers,
and/or (b) requires answers to a host of other questions, each of
which have to be answered separately. Example: "Have you left
29. Fallacy of misleading context. Arguing by misrepresenting,
distorting, omitting or quoting something out of context.
30. Fallacy of prejudice. Arguing from a bias or emotional
identification or involvement with an idea (argument, doctrine,
31. Fallacy of red herring. Ignoring criticism of an argument by
changing attention to another subject. Examples: "You believe in
abortion, yet you don't believe in the right-to-die-with-dignity
bill before the legislature."
32. Fallacy of slanting. Deliberately omitting, deemphasizing, or
overemphasizing certain points to the exclusion of others in order
to hide evidence that is important and relevant to the conclusion
of the argument and that should be taken into account of in an
33. Fallacy of special pleading. (a) Accepting an idea or criticism
when applied to an opponent's argument but rejecting it when
applied to one's own argument. (b) rejecting an idea or criticism
when applied to an opponent's argument but accepting it when
applied to one's own.
34. Fallacy of the straw man. Presenting an opponent's position in
as weak or misrepresented a version as possible so that it can be
easily refuted. Example: "Darwinism is in error. It claims that
we are all descendents from an apelike creature, from which we
evolved according to natural selection. No evidence of such a
creature has been found. No adequate and consistent explanation of
natural selection has been given. Therefore, evolution according
to Darwinism has not taken place."
35. Fallacy of the beard. Arguin (a) that small or minor
differences do not (or cannot) make a difference, or are not (or
cannot be) significant, or (b) arguing so as to find a definite
point at which something can be named. For example, insisting that
a few hairs lost here and there do not indicate anything about my
impending baldness; or trying to determine how many hairs a person
must have before he can be called bald (or not bald).
36. Fallacy of tu quoque (you also). (a) Presenting evidence that a
person's actions are not consistent with that for which he is
arguing. Example: "John preaches that we should be kind and
loving. He doesn't practice it. I've seen him beat up his kids."
(b) Showing that a person's views are inconsistent with what he
previously believed and therefore (1) he is not to be trusted,
and/or (2) his new view is to be rejected. Example: "Judge Egener
was against marijuana legislation four years ago when he was
running for office. Now he is for it. How can you trust a man who
can change his mind on such an important issue? His present
position is inconsistent with his earlier view and therefore it
should not be accepted." (c) Sometimes related to the Fallacy of
two wrongs make a right. Example: The Democrats for years used
illegal wiretapping; therefore the Republicans should not be
condemned for their use of illegal wiretapping.
37. Fallacy of unqualified source. Using as support in an argument
a source of authority that is not qualified to provide evidence.
38. Gambler's fallacy. (a) Arguing that since, for example, a penny
has fallen tails ten times in a row then it will fall heads the
eleventh time or (b) arguing that since, for example, an airline
has not had an accident for the past ten years, it is then soon due
for an accident. The gambler's fallacy rejects the assumption in
probability theory that each event is independent of its previous
happening. The chances of an event happening are always the same
no matter how many times that event has taken place in the past.
Given those events happening over a long enough period of time then
their frequency would average out to 1/2. Sometimes referred to as
the Monte Carlo fallacy (a generalized form of the gambler's
fallacy): The error of assuming that because something has happened
less frequently than expected in the past, there is an increased
chance that it will happen soon.
39. Genetic fallacy. Arguing that the origin of something is
identical with that thing with that from which it originates.
Example: 'Consciousness originates in neural processes. Therefore,
consciousness is (nothing but) neural processes. Sometimes
referred to as the nothing-but fallacy, or the REDUCTIVE FALLACY.
(b) Appraising or explaining something in terms of its origin, or
source, or beginnings. (c) Arguing that something is to be
rejected because its origins are [unknown] and/or suspicious.
40. Pragmatic fallacy. Arguing that something is true because it
has practical effects upon people: it makes them happier, easier to
deal with, more moral, loyal, stable. Example: "An immortal life
exists because without such a concept men would have nothing to
live for. There would be no meaning or purpose in life and
everyone would be immoral."
41. Pathetic fallacy. Incorrectly projecting (attributing) human
emotions, feeling, intentions, thoughts, traits upon events or
objects which do not possess the capacity for such qualities.
42. Naturalist fallacy (ethics). 1. The fallacy of reducing ethical
statements to factual statements, to statements about natural
events. 2. The fallacy of deriving (deducing) ethical statements
from nonethical statements. [is/ought fallacy]. 3. The fallacy of
defining ethical terms in nonethical (descriptive, naturalistic, or
factual) terms [ought/is fallacy].
Fallacy, classification of informal. Informal fallacies may be classified
in a variety of ways. Three general categories:
(a) Material fallacies have to do with the facts (the matter, the
content) of the argument in question. Two subcategories of material
(1) fallacies of evidence, which refer to arguments that do not
provide the required factual support (ground, evidence) for their
(2) fallacies of irrelevance (or relevance) which refer to
arguments that have supporting statements that are irrelevant to
the conclusion being asserted and therefore cannot establish the
truth of that conclusion.
(b) Linguistic fallacies have to do with defects in arguments such
as ambiguity (in which careless shifts of meanings or linguistic
imprecisions lead to erroneous conclusions), vagueness, incorrect
use of words, lack of clarity, linguistic inconsistencies,
(c) Fallacies of irrelevant emotional appeal have to do with
affecting behavior (responses, attitudes). That is, arguments are
presented in such a way as to appeal to one's prejudices, biases,
loyalty, dedication,fear, guilt, and so on. They persuade, cajole,
threaten, or confuse in order to win assent to an argument.
I hope that these definitions and examples are helpful and responsive. I have found them very useful. (Ben Cushman and Reed College)