Reflections: There are many errors in reasoning that we come across. One special kind, called a fallacy, is especially important for us to study. Fallacies are not only pervasive; they often convince people to positions that are not supported by the evidence. In other words, a fallacy is a deceptive or misleading argument that may persuade us, but is nevertheless unsound. Every fallacy contains a fundamental flaw in reasoning. The flaws can take any number of forms and may involve structural or linguistic errors, mistaken assumptions, or premises that are irrelevant to the conclusion stated. It is fascinating and quite satisfying to acquire a facility with spotting and naming the many fallacies we run across in our lives.

Goals for this Chapter: My goal in this chapter to present the major fallacies of reasoning that we come across. Having a knowledge of fallacies is empowering. It enables us to spot patterns of incorrect reasoning and see why they are incorrect. It also helps us sharpen our own thinking processes so we can avoid committing these fallacies ourselves.

Fallacies, Fallacies:
Steering Clear of Argumentative Quicksand
There are four major kinds of fallacies: fallacies of relevance, fallacies of presumption, fallacies of ambiguity, and formal fallacies. We'll start with an overview and then look at each fallacy.

Fallacies of Relevance. In these fallacies the premises simply fail to support the conclusion; they are beside the point. For example: "Lance Armstrong likes to do long-distance bicycling, why don't you? It'd do wonders for your stamina!'

Fallacies of Presumption. In these fallacies the argument depends upon an unwarranted assumption causing the fallacy. For example: "Have you always been a wacko?" [Presumes you were wacko and the question is if you still are].

Fallacies of Ambiguity (also known as Linguistic Fallacies). These fallacies center on the use of language in terms of emphasis, interpretation, sentence structure, or the relationship between the parts and the whole. This ambiguity results in an incorrect conclusion being drawn, causing the fallacy. For example: "I saw Trent petting his cat Bobo, so I gave him some chicken scraps." [who got the chicken scraps--Trent or Bobo?]

Formal Fallacies. These fallacies occur because of a structural error. As a result, the very form of the reasoning is incorrect. The truth of the premises will never guarantee the truth of the conclusion because of a structural error. For example: "If Keith eats another bag of popcorn, he will feel sick. Keith did not eat another bag of papcorn, so he won't feel sick." [he could get sick from eating a gallon of ice cream].

I. Introduction to the Fallacies of Relevance

Fallacies of Relevance rest on evidence that's beside the point and, thus, irrelevant. There is always a glaring gap between the premises and the conclusion drawn in a fallacy of relevance. The key is what counts as a good reason, not what counts as persuasive. A good reason is something that offers solid evidence for holding a position. By becoming familiar with the fallacies, we'll be able to spot incorrect reasoning in ourselves and in others and, hopefully, stop ourselves from falling into any fallacious thinking.

1. Argumentum Ad Hominem
This fallacy occurs when a personal attack is used to discredit an opponent (or source of an idea) instead of focusing on the individual's ideas. Often it is done in an abusive way. As a result, instead of attacking the idea, theory or proposal, there is an attack on the person who submits it. This may occur in day-to-day encounters, as well as on the public stage.

2. Argumentum Ad Hominem Circumstantial
This fallacy occurs when there is an attempt to discredit an opponent because of their special circumstances. Instead of focusing upon the idea, argument, or proposal, an ad hominem circumstantialfallacy is committed when an attack is launched because of the person's self-interest or affiliation (such as professional, religious, cultural, or political associations). The fallacy is that the opponent's position does not rest on a reasoned defense or solid evidence, but on these corrupting influences.

The difference between ad hominem and ad hominem circumstantial is that the former is a personal attack, direct abuse or insult that is intended to demean them personally and, thereby, squash their argument. In contrast, an ad hominem circumstantial goes after the person's circumstances, connections, or situation rather than individual's personal traits or character.

3. Tu Quo (or Tu Quoque--"You're Another One")
The fallacy of Tu Quo occurs when there's an attempt to discredit someone because their actions are not in keeping with their words or they don't "practice what they preach." Because an advocate of a position appears to be acting in contradictory way on the very position, it may be fallaciously claimed that the argument has no merit. However, hypocrites may exhibit strong reasoning, even if they fail to take their own advice. Our personal habits and practices are generally irrelevant to the merits of an argument.A variation of tu quo is when it is fallaciously argued that an action, idea, or proposal is justifiable because others are guilty of doing it too. (e.g, "You smoke, mommy, why can't I? It must not be so bad, since you smoke two packs a day.")

4. Argumentum Ad Populum (Appeal to the Masses)
This fallacy occurs when there is an attempt to persuade on the basis of popular appeal, mass sentiment, or patriotism, rather than giving good reasons to accept the conclusion. "Snob appeal" would be included here.

5. Argumentum Ad Vericundiam (Appeal to Authority)
This fallacy occurs when, instead of drawing upon solid evidence, a famous person or celebrity is cited in order to get a conclusion accepted. What makes it a fallacy is that the authority cited is not a credible expert in the area. Thus, it is expected that we'll be persuaded by the endorsement, rather than good reasons for the conclusion.

6. Argumentum Ad Baculum (Appeal to Force or Coercion)
This fallacy occurs when there is the use of force, the threat of force, or coercion in order to get a conclusion accepted. This includes verbal or sexual harassment, blackmail, extortion, and threat of violence used to "persuade" someone to a position. A variation is bribery, where the coercion comes in the form of a promise, offer, money, or position that motivates with a combination of desire (to have something) and fear (that the opportunity will pass if we turn down the bribe). Here's an example of an ad that points to unfortunate

7. ArgumentumAd Misericordiam (Appeal to Pity)
This fallacy occurs when there is an irrelevant appeal to pity or a set of sorrowful circumstances in order to get a conclusion accepted. A sympathetic response may be called for when knowing of someone's personal difficulties. But that does not, in itself, substitute for good reasons that directly support a conclusion.

8. Argumentum Ad Ignorantiam (Appeal to Ignorance)
This fallacy occurs when it is argued that something is the case (either true or false) simply because you cannot prove otherwise. This is the "if you can't prove me wrong, then I must be right!" defense.

II. Key Fallacies Of Presumption

We have all fallen victim to unwarranted assumptions. People make unwarranted assumptions all the time. Some of the major ways this occurs have been categorized and named, as we will see. What makes fallacies of presumption unsound arguments is that they all contain an unstated assumption that, being erroneous, causes the argument to sink. In each case the unwarranted assumption, once uncovered, reveals how weak is the argument. There are 10 key fallacies of presumption that we will look at below.

1. Accident
This occurs when a general rule or principle is applied to a special case in which, by reason of its special or atypical characteristics, the rule simply does not apply. This fallacy might be a misapplication of a moral principle, a rule from work, or a general pronouncement made by a family member or friend. The unwarranted assumption is that the rule applies to all cases, without exception. But most rules and principles simply fail to apply across the board and so there are exceptions that make the rule inapplicable. The fallacy of accident occurs when this is not recognized.

2. Hasty Generalization
This occurs when a generalization or moral principle is drawn on the basis of too small a sample or an atypical case. Stereotypes and other poor inferences have been drawn about entire groups of people on the basis of either too little information or a group that is not representative. Hasty generalization often occurs because the sample size is too small. Therefore, the inference drawn is an incorrect generalization.

3. Biased Statistics
This fallacy occurs when an inference is drawn on the basis of a sample that is not diverse enough. That is, the sample is not representative of the target population. We see this in studies that exclude a certain age group, gender, ethnic group, and so on--and yet draw a generalization to a population which includes the omitted group. In all of these cases, there is a shift from the sample population to the target population. That is the way to spot a case of biased statistics. Compare the sample group (teenage boys, toddlers, community college students) to the targeted population (Americans, children, students) to determine if it is sufficiently representative.

4. Bifurcation (Also Known as "False Dichotomy" or "Excluded Middle")
The fallacy of bifurcation involves the presentation of an "either/or" situation when, in fact, there are more than two options. It is often expressed as a choice between this or that; but there are other constructions. For example: "If you don't do this, then that is going to happen" or "You could do this. You could do that. Your choice." Assuming there are other options and only these two are presented, then a better choice may have been left out. It's a false dichotomy. It often occurs when others are manipulating the choices; so we may not even realize what was left out. It can hardly be said to be "informed consent" if we don't know the range of options.

5. Complex Question
This fallacy is in the form of a question in which two questions are rolled into one. The answer to the hidden, unasked question is assumed, thereby creating the fallacy.

6. Post Hoc (or Post Hoc Ergo Propter Hoc--"After This Therefore because Of This")
This fallacy asserts a causal connection that rests on something happening earlier in time. The fallacy goes like this: Because something precedes something else means that it must then cause the later thing to happen. No evidence given to support such a causal link. Any connection might be coincidental. It would be unwarranted to assume a causal connection.

7. Red Herring
This fallacy occurs when an irrelevant line of reasoning is intentionally used to divert people away from the topic at hand. We see this when someone purposely shifts the subject of the conversation to avoid an incriminating line of questioning or to deceive someone. It's called a red herring, because a stinking little herring (fish) is an effective way to lead the hound dogs off the scent. Most of us have seen red herring fallacies. People often jump around topics: Some families regularly communicate by going from one topic to the next and back to the first. But what marks a red herring is that the change of topic is done with the intent to deceive and divert attention from one thing to another.

8. Slippery Slope
In this case, an argument is made against something on the basis that, if it is allowed, it will lead to something worse which, in turn, leads to something even worse and so on (down the slippery slope). Behind this reasoning is the unstated assumption that the first in the causal chain leads to the second and that leads to the third, and so on. The argument is that a negative chain of events will follow from something being put into effect. There is no attempt to prove the one situation actually does lead to the next one or that situation to an even worse one. Rather, the connection is incorrectly assumed and not proven. Note: Not all propositions that involve causal chains are slippery slopes. If it is demonstrated that Situation A leads to situation B and so on, they are not committing slippery slope. The fallacy occurs when the chain is asserted, but not proven.

9. Straw Man Fallacy
This fallacy occurs when an opponent's position is presented as so extreme that it's indefensible. We are then steered toward another, more moderate or appealing, position, which offered as the alternative. The image of the "straw man" (scare crow) is that of something so flimsy that it will go up in smoke if we put a match near it.With the straw man fallacy, the opposition is painted as much more extreme than it actually is. What usually happens is that the speaker's own position is offered as the preferred, reasonable alternative.

10. Begging the Question (Petitio Principii)
This fallacy consists of circular reasoning, whereby the speaker assumes what she or he is trying to prove. The conclusion is drawn on the basis of evidence containing a restatement of the conclusion itself. Because of this repetition, it is called begging the question.

Question-Begging Epithets. One of the variations of begging the question rests on the use of highly slanted language. Here, biased language stacks the deck with language that is slanted in one direction or another. The result is that it is difficult to stay focused on the issue. Question-begging epithets are either a euphemism or a dyslogism (name-calling)--biased in a very positive (praiseworthy) way or biased in a highly negative (critical) way in terms of descriptions of people or situations.

III. Key Fallacies Of Ambiguity

Fallacies of ambiguity, also known as linguistic fallacies, are so named because of an unclear sentence structure, grammar, or use of words. The result of the ambiguity is that an incorrect conclusion is drawn. Let's look at the different types of fallacies of ambiguity. There are five main fallacies of ambiguity, with the flawed reasoning related to confusions created by such things as shifting meanings of words, misleading emphasis of a word or phrase, unclear sentence structure, or mistaken inferences from parts to wholes, or vice versa. Let's look at these types of fallacies.

1. Equivocation
This fallacy occurs when two or more different meanings of a single word or phrase are used in the same context. The resulting ambiguity leads to an incorrect conclusion being drawn. This is also known as a semantic fallacy. We often see equivocation in puns and jokes. A special kind of equivocation has to do with "relative terms"-- which have different meanings in different contexts (like "tall" or "big" or "small"). We also see equivocation playing on the sound of a word, for example, "How do you make antifreeze? Steal her blanket." The word "antifreeze" sounds like "Auntie freeze," thus the joke.

2. Accent
This fallacy occurs when, because of the way a word or phrase is visually or verbally emphasized, we are led to drawing an incorrect conclusion. This includes the repetition of a word or phrase to create a certain effect that leads to an incorrect conclusion. Think, for example, of ads where the word "Free" is accented but, in tiny print, we are told what we have to do or buy to get the freebie. Another way the fallacy of accent occurs is when someone misquotes someone or takes something out of context.

3. Amphiboly
This fallacy occurs because of an ambiguity created by the use of grammar or sentence structure. This is also known as a fallacy of syntax. Think of an amphibian--a creature that can live in two entirely different environments. The fallacy of amphiboly occurs when the sentence structure is confusing, leading to an incorrect conclusion being drawn. Sometimes amphiboly results from two nouns preceding the verb or two nouns with an unclear reference afterward (as in "Baby George walked toward grandpa, his diaper falling to his knees"). Sometimes the fallacy results from a missing verb. If the sentence structure seems awkward or funny, check for amphiboly.

4. Composition
This fallacy occurs when it is inferred from what is true of the parts or members of something that is true of the whole thing (or organization). The fact that something is true of the members or parts of something does not mean that it will be true of the whole. For example, there could be a football team where every member is a great athlete, but they do not work well as a team. Similarly, great musicians might jam together, but be unable to produce great music.

5. Division
This fallacy occurs when we infer that what is true of a whole or organization is also true of its parts or members. This is the opposite of composition. There we went from what was true of each and every part and then argued it must be true of the whole. The fallacy of Division occurs when it is argued that simply because something is true of a whole (or an organization) that it will necessarily follow that each part or member has that characteristic too.

Formal Fallacies

These fallacies occur because of a structural error. As a result, the very form of the reasoning is incorrect. The truth of the premises will never guarantee the truth of the conclusion because of a structural error.

1. Fallacy of Affirming the Consequent
This fallacy takes the form: "If A then B. B, therefore A." For example, "If the rain continues, the roof will collapse. The roof collapsed. Therefore, the rain continued." But, any number of things could cause a roof collapse, e.g., if the neighbor's oak tree fell on the roof after it was struck by lightning.

2. Fallacy of Denying the Antecedent
This fallacy takes the form: If A then B. Not A, therefore not B." For example, "If it snows through the night, we will light a fire at breakfast time. It did not snow through the night, therefore we did not light a fire at breakfast time." But, we may light a fire at breakfast time even if it didn't snow; e.g., there was a terrible cold snap or the electricity went out or we want the house to look pretty for our relatives who are coming over.