42 Fallacies

Question 0

Ad Hominem Tu Quoque

Answer 0

1. Person A makes claim X.
2. Person B asserts that A’s actions or past claims are inconsistent with the truth of claim X.
3. Therefore X is false.

The fact that a person makes inconsistent claims does not make any particular claim he makes false (although of any pair of inconsistent claims only one can be true—but both can be false). Also, the fact that a person’s claims are not consistent with his actions might indicate that the person is a hypocrite but this does not prove his claims are false.

Question 1

Ad Hominem

Answer 1

1. Person A makes claim X.
2. Person B makes an attack on person A.
3. Therefore A’s claim is false.

The reason why an ad Hominem (of any kind) is a fallacy is that the character, circumstances, or actions of a person do not (in most cases) have a bearing on the truth or falsity of the claim being made (or the quality of the argument being made).

Question 2

Appeal to the Consequences of a Belief

Answer 2

2: X is false because if people did not accept X as being false, then there would be negative consequences.

1: X is true because if people did not accept X as being true, then there would be negative consequences.

#5: I wish that X were true, therefore X is true. This is known as Wishful Thinking.
 #6: I wish that X were false, therefore X is false. This is known as Wishful Thinking.

Question 3

RRB

Answer 3

Rational Reason to Believe

A RRB is evidence that objectively and logically supports the claim.

Question 4

PRB

Answer 4

Prudential Reason to Believe

A PRB is a reason to accept the belief because of some external factor (such as fear, a threat, or a benefit or harm that may stem from the belief) that is relevant to what a person values but is not relevant to the truth or falsity of the claim.

Question 5

Appeal to Authority

Answer 5

1) Person A is (claimed to be) an authority on subject S.
2) Person A makes claim C about subject S.
3) Therefore, C is true.

Initial premise is not sound.

Question 6

6 standards for authority

Answer 6

1. The person has sufficient expertise in the subject matter in question.
2. The claim being made by the person is within her area(s) of expertise.
3. There is an adequate degree of agreement among the other experts in the subject in question.
4. The person in question is not significantly biased.
5. The area of expertise is a legitimate area or discipline.
6. The authority in question must be identified.

It should be noted that even a good Appeal to Authority is not an exceptionally strong argument.

Question 7

Appeal to Belief

Answer 7

1) Most people believe that a claim, X, is true.
2) Therefore X is true.

This line of “reasoning” is fallacious because the fact that many people believe a claim does not, in general, serve as evidence that the claim is true.

Question 8

Appeal to Common Practice

Answer 8

1) X is a common action.
2) Therefore X is correct/moral/justified/reasonable, etc.

The basic idea behind the fallacy is that the fact that most people do X is used as “evidence” to support the action or practice. It is a fallacy because the mere fact that most people do something does not make it correct, moral, justified, or reasonable.

Question 9

Appeal to Fair Play

Answer 9

Is not always a fallacy. For example, a woman working in an office might say “the men who do the same job as me get paid more than I do, so it would be right for me to get paid the same as them.” This would not be a fallacy as long as there was no relevant difference between her and the men (in terms of ability, experience, hours worked, etc.).

More formally:

1) It is common practice to treat people of type Y in manner X and to treat people of type Z in a different manner.
2) There is no relevant difference between people of type Y and type Z.
3) Therefore people of type Z should be treated in manner X, too.

Question 10

Principle of Relevant Difference

Answer 10

A and B can only be treated differently if and only if there is a relevant difference between them. For example, it would be fine for me to give a better grade to A than B if A did better work than B.

However, it would be wrong of me to give A a better grade than B simply because A has red hair and B has blonde hair.

Question 11

Appeal to Emotion

Answer 11

1) Favorable emotions are associated with X.
2) Therefore, X is true.

This fallacy is committed when someone manipulates peoples’ emotions in order to get them to accept a claim as being true. More formally, this sort of “reasoning” involves the substitution of various means of producing strong emotions in place of evidence for a claim.

In all fairness it must be noted that the use of tactics to inspire emotions is an important skill.

As long as one is able to clearly distinguish between what inspires emotions and what justifies a claim, one is unlikely to fall prey to this fallacy.

Question 12

Appeal to Popularity

Answer 12

1) Most people approve of X.
2) So, I should approve of X, too.
3) Since I approve of X, X must be true.

On this view, in an Appeal to Popularity the claim is accepted because most people approve of the claim. In the case of an Appeal to Emotion the claim is accepted because the individual approves of the claim because of the emotion of approval he feels in regards to the claim.

Question 13

Appeal to Fear

Answer 13

Ad Baculum

1) Y is presented (a claim that is intended to produce fear).
2) Therefore claim X is true (a claim that is generally, but need not be, related to Y in some manner).

It is important to distinguish between a rational reason to believe (RRB) (evidence) and a prudential reason to believe(PRB) (motivation). A RRB is evidence that objectively and logically supports the claim. A PRB is a reason to accept the belief because of some external factor (such as fear, a threat, or a benefit or harm that may stem from the belief) that is relevant to what a person values but is not relevant to the truth or falsity of the claim.

Question 14

Appeal to Flattery

Answer 14

1) Person A is flattered by person B. 2) Person B makes claim X.
3) Therefore X is true.

The basic idea behind this fallacy is that flattery is presented in the place of evidence for accepting a claim. This sort of “reasoning” is fallacious because flattery is not, in fact, evidence for a claim.

Question 15

Appeal to Novelty

Answer 15

1. X is new.

2. Therefore X is correct or better.

Question 16

Appeal to Pity

Answer 16

An Appeal to Pity is a fallacy in which a person substitutes a claim intended to create pity for evidence in an argument. The form of the “argument” is as follows:

1. P is presented, with the intent to create pity.
2. Therefore claim C is true

Question 17

Appeal to Popularity; Ad Populum

Answer 17

1) Most people approve of X (have favorable emotions towards X).
2) Therefore X is true.

This fallacy is vaguely similar to such fallacies as Appeal to Belief and Appeal to Common Practice. However, in the case of an Ad Populum the appeal is to the fact that most people approve of a claim. In the case of an Appeal to Belief, the appeal is to the fact that most people believe a claim. In the case of an Appeal to Common Practice, the appeal is to the fact that many people take the action in question.

Question 18

Appeal to Ridicule

Answer 18

1. X, which is some form of ridicule is presented (typically directed at the claim).
2. Therefore claim C is false.

It should be noted that showing that a claim is ridiculous through the use of legitimate methods (such as a non fallacious argument) can make it reasonable to reject the claim.

Question 19

Reductio ad Absurdam

Answer 19

“Reducing to Absurdity”

In this sort of argument, the idea is to show that a contradiction (a statement that must be false) or an absurd result follows from a claim.

Question 20

Appeal to Spite

Answer 20

1. Claim X is presented with the intent of generating spite.
2. Therefore claim C is false (or true)

Of course, there are cases in which a claim that evokes a feeling of spite or malice can serve as legitimate evidence. However, it should be noted that the actual feelings of malice or spite are not evidence.

Question 21

Appeal to Tradition

Answer 21

1. X is old or traditional

2. Therefore X is correct or better.

Question 22

Begging the Question

Answer 22

Petitio Principii

1. Premises in which the truth of the conclusion is claimed or the truth of the conclusion is assumed (either directly or indirectly).
2. Claim C (the conclusion) is true.

Begging the Question is a fallacy in which the premises include the claim that the conclusion is true or (directly or indirectly) assume that the conclusion is true. This sort of “reasoning” typically has the following form.

Question 23

Biased Generalization

Answer 23

Loaded Sample, Prejudiced Statistics, Prejudiced Sample, Loaded Statistics, Biased Induction, Biased Generalization

1. Sample S, which is biased, is taken from population P.
2. Conclusion C is drawn about Population P based on S.

The person committing the fallacy is misusing the following type of reasoning, which is known variously as Inductive Generalization, Generalization, and Statistical Generalization:

1. X% of all observed A’s are B’s.
2. Therefore X% of all A’s are B’s.

The general idea is that biased samples are less likely to contain numbers proportional to the whole population.

Question 24

Unbiased Samples

Answer 24

1. Random Sample: This is a sample that is taken in such a way that nothing but chance determines which members of the population are selected for the sample. Ideally, any individual member of the population has the same chance as being selected as any other. Unfortunately, creating an ideal random sample is often very difficult.
2. Stratified Sample: This is a sample that is taken by using the following steps: 1) The relevant strata (population subgroups) are identified, 2) The number of members in each stratum is determined and 3) A random sample is taken from each stratum in exact proportion to its size.
3. Time Lapse Sample: This type of sample is taken by taking a stratified or random sample and then taking at least one more sample with a significant lapse of time between them. After the two samples are taken, they can be compared for changes.

Question 25

Burden of Proof

Answer 25

Ad Ignorantiam

Burden of Proof is a fallacy in which the burden of proof is placed on the wrong side.

1. Claim X is presented by side A and the burden of proof actually rests on side B.
2. Side B claims that X is false because there is no proof for X.

Question 26

Circumstantial Ad Hominem

Answer 26

1. Person A makes claim X.
2. Person B asserts that A makes claim X because it is in A’s interest to claim X.
3. Therefore claim X is false.
4. Person A makes claim X.
5. Person B makes an attack on A’s circumstances.
6. Therefore X is false.

Question 27

Fallacy of Composition

Answer 27

The fallacy of Composition is committed when a conclusion is drawn about a whole based on the features of its constituents when, in fact, no justification provided for the inference.

1. Individual F things have characteristics A, B, C, etc.
2. Therefore, the (whole) class of F things has characteristics A, B, C, etc.
3. The parts of the whole X have characteristics A, B, C, etc.
4. Therefore the whole X must have characteristics A, B, C.

Question 28

Confusing Cause and Effect

Answer 28

1) A and B regularly occur together. 2) Therefore A is the cause of B.

This fallacy is committed when a person assumes that one event must cause another just because the events occur together.

Question 29

Fallacy of Division

Answer 29

The fallacy of Division is committed when a person infers that what is true of a whole must also be true of its constituents and justification for that inference is not provided. There are two main variants of the general fallacy of Division:
The first type of fallacy of Division is committed when
1) a person reasons that what is true of the whole must also be true of the parts and
2) the person fails to justify that inference with the required degree of evidence. More formally, the “reasoning” follows this sort of pattern:
1. The whole, X, has properties A, B, C, etc.
2. Therefore the parts of X have properties A,B,C, etc.

The second version of the fallacy of division is committed when a person

1) draws a conclusion about the properties of individual members of a class or group based on the collective properties of the class or group and
2) there is not enough justification for the conclusion. More formally, the line of “reasoning” is as follows:
1. As a collective, group or class X has properties A,B,C, etc.
2. Therefore the individual members of group or class X have properties A,B,C, etc.

Question 30

False Dilemma

Answer 30

Black & White Thinking

1. Either claim X is true or claim Y is true (when X and Y could both be false).
2. Claim Y is false.
3. Therefore claim X is true.

This line of “reasoning” is fallacious because if both claims could be false, then it cannot be inferred that one is true because the other is false.

Question 31

Gambler’s Fallacy

Answer 31

1. X has happened.
2. X departs from what is expected to occur on average or over the long term.
3. Therefore, X will come to an end soon.

The first involves events whose probabilities of occurring are independent of one another. For example, one toss of a fair (two sides, non‐loaded) coin does not affect the next toss of the coin. So, each time the coin is tossed there is (ideally) a 50% chance of it landing heads and a 50% chance of it landing tails. Suppose that a person tosses a coin 6 times and gets a head each time. If he concludes that the next toss will be tails because tails “is due”, then he will have committed the Gambler’s Fallacy.

The second involves cases whose probabilities of occurring are not independent of one another. For example, suppose that a boxer has won 50% of his fights over the past two years. Suppose that after several fights he has won 50% of his matches this year, that he his lost his last six fights and he has six left. If a person believed that he would win his next six fights because he has used up his losses and is “due” for a victory, then he would have committed the Gambler’s Fallacy.

Question 32

Genetic Fallacy

Answer 32

A perceived defect in the origin of a claim or thing is taken to be evidence that discredits the claim or thing itself. It is also a line of reasoning in which the origin of a claim or thing is taken to be evidence for the claim or thing. This sort of “reasoning” has the following form:

1. The origin of a claim or thing is presented.
2. The claim is true(or false) or the thing is supported (or discredited).

Question 33

Guilt by Association

Answer 33

Guilt by Association is a fallacy in which a person rejects a claim simply because it is pointed out that people she dislikes accept the claim. This sort of “reasoning” has the following form:

1. It is pointed out that person A accepts claim P.
2. Therefore P is false

Question 34

Hasty Generalization

Answer 34

Fallacy of Insufficient Statistics, Fallacy of Insufficient Sample, Leaping to A Conclusion, Hasty Induction

This fallacy is committed when a person draws a conclusion about a population based on a sample that is not large enough. It has the following form:

1. Sample S, which is too small, is taken from population P.
2. Conclusion C is drawn about Population P based on S.

Question 35

Ignoring a Common Cause

Answer 35

1) A and B are regularly connected (but no third, common cause is looked for).
2) Therefore A is the cause of B.

This fallacy is committed when it is concluded that one thing causes another simply because they are regularly associated.

Question 36

Middle Ground

Answer 36

Golden Mean Fallacy, Fallacy of Moderation

1. Position A and B are two extreme positions.
2. C is a position that rests in the middle between A and B.
3. Therefore C is the correct position.

Many times a moderate position is correct. However, the claim that the moderate or middle position is correct must be supported by legitimate reasoning.

Question 37

Misleading Vividness

Answer 37

Misleading Vividness is a fallacy in which a very small number of particularly dramatic events are taken to outweigh a significant amount of statistical evidence. This sort of “reasoning” has the following form:

1. Dramatic or vivid event X occurs (and is not in accord with the majority of the statistical evidence) .
2. Therefore events of type X are likely to occur.

Question 38

Peer Pressure

Answer 38

1. Person P is pressured by his/her peers or threatened with rejection. 2. Therefore person P’s claim X is false.

Question 39

Personal Attack

Answer 39

Ad Hominem Abusive

A personal attack is committed when a person substitutes abusive remarks for evidence when attacking another person’s claim or claims.

In general, it is best to focus one’s attention on the content of the claim and not on who made the claim. It is the content that determines the truth of the claim and not the characteristics of the person making the claim.

Question 40

Poisoning the Well

Answer 40

This sort of “reasoning” involves trying to discredit what a person might later claim by presenting unfavorable information (be it true or false) about the person.

1. Unfavorable information (be it true or false) about person A is presented.
2. Therefore any claims person A makes will be false.

The person making such an attack is hoping that the unfavorable information will bias listeners against the person in question and hence that they will reject any claims he might make.

Question 41

Post Hoc Ergo Propter Hoc

Answer 41

1) A occurs before B.

2) Therefore A is the cause of B.

Question 42

Questionable Cause

Answer 42

1) A and B are associated on a regular basis.
2) Therefore A is the cause of B.

The general idea behind this fallacy is that it is an error in reasoning to conclude that one thing causes another simply because the two are associated on a regular basis.

Question 43

Red Herring

Answer 43

1. Topic A is under discussion.
2. Topic B is introduced under the guise of being relevant to topic A (when topic B is actually not relevant to topic A).
3. Topic A is abandoned.

Question 44

Relativist Fallacy

Answer 44

The Relativist Fallacy is committed when a person rejects a claim by asserting that the claim might be true for others but is not for him/her. This sort of “reasoning” has the following form:

1. Claim X is presented.
2. Person A asserts that X may be true for others but is not true for him/her.
3. Therefore A is justified in rejecting X.

Question 45

Slippery Slope

Answer 45

The Slippery Slope is a fallacy in which a person asserts that some event must inevitably follow from another without any argument for the inevitability of the event in question. In most cases, there are a series of steps or gradations between one event and the one in question and no reason is given as to why the intervening steps or gradations will simply be bypassed. This “argument” has the following form:

1. Event X has occurred (or will or might occur).
2. Therefore event Y will inevitably happ

Question 46

Special Pleading

Answer 46

1. Person A accepts standard(s) S and applies them to others in circumstance(s) C.
2. Person A is in circumstance(s) C.
3. Therefore A is exempt from S.

The person committing Special Pleading is claiming that he is exempt from certain principles or standards yet he provides no good reason for his exemption.

Question 47

Spotlight

Answer 47

The Spotlight fallacy is committed when a person uncritically assumes that all members or cases of a certain class or type are like those that receive the most attention or coverage in the media. This line of “reasoning” has the following form:

1. Xs with quality Q receive a great deal of attention or coverage in the media.
2. Therefore all Xs have quality Q.

Question 48

Straw Man

Answer 48

The Straw Man fallacy is committed when a person simply ignores a person’s actual position and substitutes a distorted, exaggerated or misrepresented version of that position. This sort of “reasoning” has the following pattern:

1. Person A has position X.
2. Person B presents position Y (which is a distorted version of X).
3. Person B attacks position Y.
4. Therefore X is false/incorrect/flawed.

Question 49

Two Wrongs Make a Right

Answer 49

1. It is claimed that person B would do X to person A.
2. It is acceptable for person A to do X to person B (when A’s doing X to B is not necessary to prevent B from doing X to A).