Logical Fallacies

1. Fallacies of relevance
    a. Argumentum ad baculum
An argument that resorts to the threat of force to cause the acceptance of the conclusion. They may also include threats of fear to cause acceptance.
Examples:
    Do this or you'll die!
    Might makes right
    If you don't practice the piano, I'll put you in time out.

b. Argumentum ad hominem
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 2) circumstantial.

    abusive: the person is attacked over what he said
example:
 Arguing with Hitler over whether the sun is shining, just because it's Hitler.

    circumstantial: attacking the circumstances the person is in
Example:
    Don't listen to the congressman; he's pro-union.

    c. Argumentum ad ignorantium
An argument that a propisition 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.

Inability to refute is taken as demonstration of their views. This is a common tactic with crackpots and conspiracy theorists.
Examples:
    We have here the names of members of the state department that are under a cloud of suspician. While we have no evidence that they are members of the communist party, we do not have evidence that they are not.

d. Argumentum ad misericordiam
An argument that appeals to pity for the sake of getting a conclusion accepted.
Example:
    Look at that poor man; doesn't your heart blead for the suffering he has endured. How can you not grant him a sizeable judgment in this case.

e. Argumentum ad populum
    An argument that appeals to the beliefs of the multitude (i.e., the populous). Another way of putting it: speaker deals with passions of audience rather than with alient issues. This fallacy is also known as "appeal to tradition". Ad populum arguments often occur in 1) propaganda 2) demagoguery, and 3) advertizing.
Examples:

1. 56 percent of the American public believes this.
2. The majority of experts hold this position.
3. Four out of five dentists agree...
4. Millions can't be wrong...
5. But we've always done it that way...

    f. Argumentum ad verecundiam
An argument in which an authority is appealed to. Ad verecundiam refers to a fallacy of simply resorting to appeals to authority. Again, very common in advertizing.
Examples:

1. Drink this soda because this famous athlete drinks it.
2. Vote this way because this famous actor will vote this way.
3. Believe this because this famous pastor (teacher) belives this.

    g. Accident
Come out of generalizations and down to specific case. Also called a Sweeping Generalization or Dicto Simpliciter. It occurs when a general rule is applied to a particular situation in which the features of that particular situation render the rule inapplicable. It is the opposite of converse accident (also call hasty generalization).

    h. Converse accident
Hasty generalization. An argument in which a proposition is used as a premise without attention given to some obvious condition that would affect the proposition's application. It is a fallacy that takes evidence from several, possibly unrepresentative, cases to a general rule; generalizing from few to many. Note the relation to statistics: much of statistics concerns whether or not a sample is representative of a larger population. The larger the sample size, the better the representativeness. Note also that the opposite of a hasty generalization is a sweeping generalization.
Example:
    My neighbors on both side of me have won the lottery, so we should play the lottery.

    i. False cause

1) non causa pro causa
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.
Example:
We should eat vegitables because animals eat them and are healthy.

2) post hoc ergo propter hoc
    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 deos not mean that the first event is the cause of the second event. This argument resembles the fallacy known as Hasty Generalization.
3) cum hoc ergo propter hoc
    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.

    j. petitio princippi
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.

Also called circular reasoning.
    k. Complex question
Hidden within the question is another question. This is also called Fallacy of Interrogation. The question asked has a presupposition which the answerer may wish to deny, but which he/she would be accepting if he/she gave anything that would count as an answer. Any answer to the question "Why does such-and-such happen?" presupposes that "such-and-such" acutally happens.
Examples:

1. Yes or no, have you stopped beating your wife?
2. Which dress should I buy, the red one or the blue one?
3. Do you want to give the babies a bath or fix dinner?

    l. Ignoratio elenchi
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." It is a non-sequitar.
Example:
A man is being tried for murder and the lawyer proves that murder is a horrible crime.
    m. argumentum ad antiquitam
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 been."
    n. argumentum ad crumenam
A falacy of believing that money is a criterion of correctness; that those with more money are more likely to be right.

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

    p. argumentum ad naseum
The incorrect belief that an assertion is more likely to be true the more often it is heard. An "argumentum ad naseum" is one that employs constant repitition in asserting a concept.

    q. argumentum ad novitam
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.

    r. argumentum ad numeram

A fallacy that asserts that the more people who support or believe a proposition then the more likely that the proposition is correct; it equates mass support with correctness.
    s. bifurcation
Also referred to as the "black and white" fallacy. Bifurcation is the presentation of a situation or condition with only two alternatives, whereas in fact other alternatives exist or can exist.

    t. Coverting a conditional
If P then Q, therefore if Q then P.
    u. False analogy
An analogy is a partial similarity between the like features of two things or events on which a comparison can be made. A false analogy involves comparing two things that are NOT similar. Note that the two things may be similar in a superficial way, but not with respect to what is being argued.

A has x
B has x
Therefore A is B

Example:
"In every country the communists have taken over, the first thing they do is outlaw cockfighting." -- John Monks, Oklahoma State Representative arguing against a bill to outlaw cockfighting.

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

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

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

    z. Straw Man

    It is a fallacy to misrepresent someone else's position for the purposes of more easily attacking it, then to knock down that misrepresented position, and then to conclude that the original position has been demolished. It is a fallacy because it fails to deal with the actual arguments that have been made.
    aa. Two Wrongs Make a Right (Tu quoque)
    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.
Example:
    The U.S. criticizes China's poor human rights record. China criticises the U.S. because of its treatment of minorities.
    bb. Shifting the Burden of Proof
The burden of proof is always on the person making the assertion or proposition. Shifting the burden of proof, a special case of "argumentum ad ignorantium," is a fallacy of putting the burden of proof on the person who denies or questions the assertion being made. The source of the fallacy is the assumption that something is true unless proven otherwise.

2. Fallacies of ambiguity
    An argument in the course of which at least one term is used in different senses. Also known as eqivocation. There are several types, for example:

    a. amphiboly

A type of fallacy of ambiguity where the ambiguity involved is of an "amphibolous" (equivocal or 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.
Example:
The department store has pants for men with 32 waists.

    b. accent due to contiguity
Two statements which are true are brought together and made confusing.
Example:

    c. equivocation
Using double meanings. Plays on words. Puns fit this category nicely.
    d. composition
An argument in which one assumes that a whole has a property solely becaus its various parts have that property.
Examples:

1. Fidel Castro, the ruler of Cuba, is a wealthy man. Therefore, Cuba must be a wealthy country.
2. Christianity preaches love, forgiveness and good deeds. Therefore, Jane, who claims to be a Christian, must be loving, forgiving, and good.
Composition may take place in two ways:
1. From each part to the whole. Example: atoms are invisible. Tables are made up of atoms. Therefore, tables are invisible.
2. From a quality distributed over each part of a whole to the collection. i.e., A, B, C, D, and E are the best basketball players in our school. Therefore they will make up the vest team.
The fallacy of composition is sometimes confused with the fallacy of converse accident (hasty generalization), if both arguments are thought of simply as proceeding from particular statements to general statements. Converse accident (hasty generalization) comes from asserting that what is true of one element (or small sample) is thus true of all. There is great danger in inadequate samples.

    e. division
An argument in which one assumes that a part has a property solely because the whole has that property.
Example:
The United States is the richest country in the world. Therefore, Andrew, a U.S. citizen, must be a wealthy man.

The fallacy of division is sometimes confused with the fallacy of accident if both arguments are thought of simply as proceeding from general statements to particular statements.
We distinguish them thus:
Division takes place when we look at a situation:
One starts with a premise asserting that some particular property belongs to a collection, and then argues to the individual member of that collection. i.e., President Carter was rejected by the voters in his second bid for office. Walter Mondale (his Vice President) is a voter. Walter Mondale rejected President Carter. Or, The U.S. Army is powerful. Therefore each soldier is powerful.
Accident takes place when we look at a rule which is USUALLY true. For instance, Knifing a man should be punished. Therefore surgeons should be punished.
    f. Reification
To reify something is to convert an abstract concept into a concrete thing. Reification is a fallacy of ambiguity. Reification is also sometimes called the fallacy of "hypostatization."

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