Logical Fallacies

Ad Hominem Abusive

fallacy is distinguished by an attack on alleged character flaws of a person instead of the person’s argument.

• abusive terms such as arrogant, overrated, stupid, liar, lazy, radical, and loser

• character assassinations divert attention away from the logical determination of the strength of an argument

Ad Hominem Abusive Example

She is old, out of touch with reality, and belongs in a loony bin. So, you cannot accept her advice on marriage.

Ad Hominem Circumstantial

fallacy occurs when someone’s argument is rejected based on the circumstances of a person’s life

• political affiliation, educational institution, place of birth, religious affiliation, and income

• racial, sexual, or religious stereotype

Ad Hominem Circumstantial Example

You told us why you are against raising taxes. But we know the real reason is that you are a billionaire, and you want to hold on to as much of your money as you can.

Poisoning the Well

occurs when a person is attacked before she has a chance to present her case. The attacker mentions something about the opponent’s character or life and uses that information to warn the audience not to believe anything they hear or read.

Poisoning the Well Example

Before you read her article “Stop All Wars,” you should know that she was arrested six times for protesting in front of the Pentagon and White House. She also has been investigated by the FBI for possible ties to peace movements in other countries, some of which resulted in violence. It is crystal clear that these kinds of people are dangerous and want to destroy our Constitution and take away our basic freedoms. We must not let them.

Tu Quoque

(meaning you too or look who’s talking). It is distinguished by the specific attempt of one person to avoid the issue at hand by claiming the other person is a hypocrite.

a. Person X presents an argument.

b. Person Y attacks the character or circumstances of person X.

c. Based solely on the attack against person X, person Y rejects person X’s argument.

Tu Quoque Example

You have been lecturing me about not joining a gang. But Dad, you were a gang member, and you never went to jail. So, I’ll make my own decision about joining a gang.

Appeal to the People

occurs when an argument manipulates a psychological need or desire, such as the desire to belong to a popular group, or the need for group solidarity, so that the reader or listener will accept the conclusion.

Appeal to the People Example

More than 80% of families have given up their old landline phones and switched to cell phones. Don’t be the last to make the change. Hurry and get yours now and feel the excitement of calling from anywhere.

Appeal to Pity

exclusively relies on a sense of pity or mercy for support of a conclusion

Appeal to Pity Example

Your honor, before you sentence my client for the murder of his parents, I ask you to consider his situation. He is an orphan. Perhaps you can give him the lightest punishment possible.

Appeal to Fear or Force

A third type of the fallacious appeal to emotion relies on fear or the threat of harmful consequences (physical or otherwise)

• The perceived threat places pressure on a person or group that, when effective, causes the person or group to reluctantly accept a course of action that otherwise would be unacceptable.

a. Person A uses psychological methods known to arouse strong emotions: appeals to group solidarity; jumping on the bandwagon; the desire to belong to an admired group; a sense of pity; and fear or the threat of force.

b. Person B is expected to accept the conclusion based solely on the emotional appeal.

Appeal to Fear or Force Example

If the workers of this company do not agree to a 25% cut in salary, then the company may have to shut its doors. Therefore, the workers of this company must agree to a 25% cut in salary.

Rigid Application of a Generalization

arises when a generalization is inappropriately applied to the case at hand. The fallacy results from the belief that the generalization or rule is universal (meaning it has no exceptions)

• We often make allowances for circumstances that permit breaking a rule.

• Once again, the mistake is believing that there are no exceptions to the rule.

• argues from the general to the specific

Rigid Application of a Generalization Example

I can’t believe the police didn’t give the driver of that ambulance any citations. He was speeding, he went through a red light, and the ambulance swerved from lane to lane without using any turn signals.

• general to the specific

Hasty Generalization

An argument that relies on a small sample that is unlikely to represent the population.

• from the specific to the general

Hasty Generalization Example

I saw a fraternity guy act rudely to a fast-food employee in the food court. Probably most fraternity and sorority members are rude and arrogant.

Composition

(1) the mistaken transfer of an attribute of the individual parts of an object to the object as a whole and (2) the mistaken transfer of an attribute of the individual members of a class to the class itself.

Composition Example

More noise is produced by a motorcycle than by a car. Therefore, more noise is produced on U.S. roadways by motorcycles than by cars.

Division

(1) the mistaken transfer of an attribute of an object as a whole to the individual parts of the object and (2) the mistaken transfer of an attribute of a class to the individual members of the class.

Division Example

The cake tastes burnt, so you must have used burnt ingredients.

Biased Sample

an argument uses a nonrepresentative sample as support for a statistical claim about an entire population. A representative sample occurs when the characteristics of a sample are correctly identified and matched to the population under investigation.

Biased Sample Example

Recently, a sample of 1000 Catholics in the United States revealed that 85% believe that abortion is morally wrong. Therefore, evidence shows that approximately 85% of all Americans believe that abortion is morally wrong.

Post Hoc

fallacy occurs from the mistaken assumption that just because one event occurred after another event, the first event must have caused the second event.

X occurred before Y, therefore X caused Y.

Post Hoc Example

Last week I bought a new car, and today I found out that I am being laid off at work. I shouldn’t have bought that car; it brought me bad luck.

Slippery Slope

An argument that attempts to connect a series of occurrences such that the first link in a chain leads directly to a second link, and so on, until a final unwanted situation is said to be the inevitable result.

Slippery Slope Example

If you start smoking marijuana for pleasure, then you will need more and more to achieve the expected high. You will begin to rely on it whenever you feel depressed. Eventually you will experiment with more powerful drugs that act faster and last longer. Of course, the amount of drug intake will have to increase to achieve the desired results. The addiction will take hold and will lead to a loss of ambition, a loss of self-esteem, the destruction of your health, and the dissolution of all social ties. Therefore, you should not start smoking marijuana.

Begging the Question

In one type, the fallacy occurs when a premise is simply reworded in the conclusion. In a second type, called circular reasoning, a set of statements seem to support each other with no clear beginning or end point. In a third type, the argument assumes certain key information that may be controversial or is not supported by facts.

Begging the Question Example

The Beatles are the greatest band of all time. So it is safe to say that no band has ever been better than the Beatles.

Complex Question

occurs when a single question actually contains multiple parts and an unestablished hidden assumption. The questioner tries to force a single answer that, in turn, is then used against the respondent. As such, the question itself is not a fallacy, but either a “yes” or “no” answer allows the questioner to create an argument that establishes the truth of the hidden assumption.

Complex Question Example

Do you still cheat on your taxes?

Appeal to Ignorance

(lack of knowledge) argument makes one of two possible mistakes: (1) A claim is made that a statement must be true because it has not been proven to be false, or (2) a claim is made that a statement must be false because it has not been proven to be true. Both claims are unjustified.

Appeal to Ignorance Example

UFOs must exist because no one has proven that they don’t exist.

Appeal to an Unqualified Authority

An argument that relies on the opinions of people who either have no expertise, training, or knowledge relevant to the issue at hand, or whose testimony is not trustworthy.

Appeal to an Unqualified Authority Example

I’m Nick Panning, quarterback of the Los Angeles Seals. I’ve been eating Oaties for breakfast since I was a kid. Oaties taste great, and they have all the nutrition kids need. You should get some for your kids today.

False Dichotomy

occurs when it is assumed that only two choices are possible, when in fact others exist. The argument contains a premise that presents an “either … or …” choice with the assumption that no other choices are available.

• G or L.

  Not L.

  G.

False Dichotomy Example

He was born on a Monday or a Thursday. He was not born on a Thursday, so he was born on a Monday.

Equivocation

occurs when the conclusion of an argument relies on an intentional or unintentional shift in the meaning of a term or phrase that was used in the premises.

Equivocation Example

My older brother tries hard to be cool. I told him he has the personality of a cucumber. Since a refrigerator is a good place to keep things cool, he should spend some time in there.

Straw Man

fallacy occurs when an argument is misrepresented in order to create a new argument that can be easily refuted. The new argument is so weak that it is “made of straw.” The arguer then falsely claims that his opponent’s real argument has been defeated.

Straw Man Example

She is against the new law that mandates teaching intelligent design alongside the theory of evolution. It should be obvious to anyone that she really wants to eliminate religious beliefs. She wants to destroy one of the basic principles of the Constitution of the United States.

Red Herring

occurs when someone completely ignores an opponent’s position. By changing the subject, the red herring “throws one off the scent,” diverting the discussion in a new direction.

Red Herring Example

Many people criticize TV as turning America into an illiterate society. How can we criticize the very medium that is the envy of countries all over the world? The entertainment quality and variety of TV programs today are greater than ever before, not to mention the enormous number of cable options available to members of the viewing audience. Thus, the critics are wrong.

Misleading Precision

occurs when a claim appears to be statistically significant but is not. Statistics are often used misleadingly.

Misleading Precision Example

In order to clear out inventory, we have reduced our used car prices by 20%. These prices won’t last forever, so you’d better hurry in and buy one of these cars before the sale ends.

Missing the Point

occurs when premises that seem to lead logically to one conclusion are used instead to support an unexpected conclusion. A conclusion “misses the point” when the premises do not adequately prepare us for it.

Missing the Point Examples

I read that it can take years to find the “black boxes” that contain crucial flight information regarding an airplane crash, and sometimes they are never found. Given this, all air travel should be suspended.