Reasoning and Fallacies

This is Unit Thirty of College Composition. Unit Twenty-Nine analyzed how language, tone and structure persuade. This unit looks beneath them, at the reasoning that holds an argument together and the fallacies that break it. Carry one idea through this lecture. A fallacy is a mistake in logic, and the question matters more than the label: explaining how the reasoning fails is worth more than naming the fallacy. A worked example near the end finds three fallacies in one short letter. By the end you will be able to separate claims, grounds and warrants. To tell deductive from inductive reasoning. To recognize the common fallacies and propaganda. And to tell a fallacy from a fair argument, in others' writing and your own.

Four entries on the working parts of an argument and the two directions reasoning moves.

What an argument is made of.

CMP 0726 Claims, Reasons and Assumptions

An argument has three working parts: the claim it asks readers to accept, the grounds offered for it, and the assumption that links them. "Texting while driving should be more tightly regulated" is a claim; accident figures are grounds; the belief that distraction causes accidents connects them. Analyzing an argument starts by separating these parts.

General to specific.

CMP 0727 Deductive Reasoning

Deductive reasoning moves from general to specific: it begins with a premise, a general concept, and examines specifics that lead to a conclusion. A writer who believes campus support for foreign students is inadequate checks clubs, language help and work-study, finds them missing, and concludes the support is lacking. A deductive conclusion is only as sound as its premise.

Specific to broad.

CMP 0728 Inductive Reasoning

Inductive reasoning moves from specific to broad: it collects details and observations, examines them, and draws a conclusion. A student who tracks class attendance for three weeks, notices that Friday attendance is lower, and concludes that many students prefer not to attend on Fridays reasons inductively. Too few observations turn induction into hasty generalization.

The link.

CMP 0729 Warrants and Assumptions

The warrant is what links the grounds to the claim, and it is often implicit, an assumption the writer expects readers to share. The texting argument assumes that distraction causes accidents; if readers doubted that, the figures would not support the claim. Ask whether a warrant is an unproven claim in disguise; an unstated assumption can carry the whole argument.

Eight entries on what a fallacy is and seven of the commonest.

Mistakes in logic.

CMP 0730 What a Fallacy Is

Fallacies are mistakes in logic, sneaky uses of flawed reasoning that suggest a writer's points may not be valid. Some writers use fallacies on purpose to seem more persuasive; many students slip into them by accident. An academic audience is likely to recognize a fallacy, and a fallacy costs the writer credibility.

Attacking the person.

CMP 0731 Ad Hominem

Ad hominem, meaning against the man, attacks the person instead of the argument, and it is often called name-calling. "He's a stupid bully and an outright thief" says nothing about his position; a source that calls opponents wackos dodges the issue. An ad hominem can derail a debate by deflecting attention from the topic.

Distorting the position.

CMP 0732 Straw Man

A straw man distorts or exaggerates an opponent's argument and then attacks the distorted version instead of the original point. Answering a proposal to reduce car traffic with "Our opponent wants to ban all cars!" attacks a position no one took. To check for a straw man, compare the position being attacked with what the opponent actually said.

Everyone is doing it.

CMP 0733 Bandwagon

The bandwagon fallacy urges people to act or think a certain way because everyone else does, and they will be excluded if they do not. "Everyone is buying these sneakers; get yours now before you're left out" is a bandwagon; so is "No one wears things like this now." A position's popularity does not make it correct.

Only two choices.

CMP 0734 False Dilemma

A false dilemma, sometimes called the either-or fallacy, presents only two options when an issue has more. Claiming that a person must either support a war or oppose the troops ignores that someone can oppose a war and still want the troops safe. A false dilemma can shift the terms of a debate, much as a straw man does.

A chain of disasters.

CMP 0735 Slippery Slope

A slippery slope argues that a single action will lead to a chain of increasingly disastrous consequences, taken as certain. "If the restaurant misses your business, it may go bankrupt" leaps from one dinner to ruin without showing the links. Consequences may be weighed, but each step must be evaluated for its own logic.

Too little evidence.

CMP 0736 Hasty Generalization

A hasty generalization is a conclusion based on inadequate or biased evidence, a body of evidence too small to support it. "Two students in this class were nervous before the test, so all students in the class must have test anxiety" generalizes from two cases. Hasty generalizations can produce stereotypes, which are both wrong and harmful.

After, so because.

CMP 0737 Causal Fallacy

The causal fallacy claims or implies that because one event followed another, the first caused the second. Losing your keys after a concert does not mean the concert caused the loss; wearing a lucky sweater on the day you aced an exam did not cause the grade. Sequence alone never establishes cause; look for the evidence that links them.

Six entries on guilt by association, circular reasoning, bait and switch, appeals to fear, fallacies that travel together, and propaganda.

Discredit by connection.

CMP 0738 Guilt by Association

Guilt by association discredits an argument by connecting its maker to a disliked group or a bad person. If two politicians support the same school-lunch bill and one has a history of corruption, citing that corruption against the other is illogical. The fallacy remains a fallacy even when the association is factually true.

The reason repeats the claim.

CMP 0739 Circular Reasoning

A circular argument restates what it has already said instead of giving a reason for it. "The book is well written because its author is a good novelist" offers the claim again as its own proof. Test a reason by asking whether it says anything new; a circular reason does not.

Accepted, then changed.

CMP 0740 Bait and Switch

Bait and switch introduces a point likely to be accepted, then changes the terms once agreement occurs. "Buy these phones at this price before they're all gone!" draws buyers in; moments later the phones are gone, and the replacements cost far more. Notice when the claim being defended differs from the one first offered.

Fear driving the response.

CMP 0741 Appeal to Fear

An appeal to fear uses fear, often exaggerated, to drive a response, making a decision seem fraught with negative consequences. A source that dwells on horrible deaths to push readers toward one policy appeals to fear rather than reasoning about the issue. Emotional appeal is a legitimate strategy; it becomes a fallacy when fear replaces evidence.

Fallacies in combination.

CMP 0742 Fallacies Travel Together

Fallacies often appear in combination, one reinforcing another. An appeal to fear often accompanies a slippery slope; guilt by association often works with hasty generalization or ad hominem, especially against a group. Naming one fallacy in a passage should prompt a search for its usual partners.

Information with an agenda.

CMP 0743 Propaganda Techniques

Propaganda is information worded to endorse a particular viewpoint, often political; two common types use the bandwagon and fear. A campaign that describes a nation in dire danger and then names one candidate as the solution uses fear propaganda. Propaganda also persuades by omission, as when a recruiting poster promises travel and training but leaves out combat.

Four entries on naming a fallacy, telling a fallacy from a fair argument, a worked example, and checking your own draft. The opening idea is paid off at the first three.

Questions in order.

CMP 0744 Naming the Fallacy

Naming a fallacy means matching what an argument does with its reasoning to a pattern. Does it attack a person or group instead of the position? Ad hominem or guilt by association. A position the opponent never took? A straw man. Does it rest on popularity? A bandwagon. Offer only two choices? A false dilemma. Predict a chain of disasters without links? A slippery slope, often with an appeal to fear. Generalize from a few cases, treat sequence as cause, or repeat the claim as its reason? Hasty generalization, causal fallacy, circular reasoning. Explaining how the reasoning fails is worth more than the name.

Resemblance is not error.

CMP 0745 Fallacy or Fair Argument

Not every argument that resembles a fallacy is one; the difference is whether the reasoning is supported. Warning of a result is fair when each step is supported, and a slippery slope when the chain is assumed. Emotion is legitimate pathos, and an appeal to fear when fear substitutes for evidence. Questioning a source's credibility is fair; attacking the person instead of the argument is ad hominem. Many representative observations are sound induction; a few cases are hasty. Narrowing choices can help a decision; excluding real options is a false dilemma. Accusing every argument of a fallacy is its own failure of analysis.

Three fallacies, one letter.

CMP 0746 An Argument With Three Fallacies

A worked example, constructed for this course, pays off the opening idea. A letter opposing later morning classes says every serious student already gets up early, which is a hasty generalization with bandwagon pressure. It links the proposal's supporters to people who want to cancel exams, which is guilt by association, and perhaps a straw man. It predicts falling attendance, collapsing grades and a ruined reputation without evidence for any link, a slippery slope ending in an appeal to fear. Its unstated warrant, that early starts cause better learning, is never supported. The analysis does not decide the policy; it shows the letter has not argued its case.

Your own reasoning.

CMP 0747 Fallacies in Your Own Draft

Checking your own draft for fallacies protects your credibility and the validity of your points. Reread each claim and ask whether you generalized from limited experience, attacked people instead of positions, or assumed a cause without evidence. Sources can contain fallacies too; avoid using a source as evidence when its reasoning is faulty.

Look at what you can now do. You can separate an argument's claim, grounds and warrant, and tell deductive reasoning from inductive. You can recognize ad hominem, the straw man, the bandwagon, the false dilemma, the slippery slope, hasty generalization and the causal fallacy. You can recognize guilt by association, circular reasoning, bait and switch, the appeal to fear, fallacies that travel together, and propaganda. And you can name a fallacy by how its reasoning fails, tell it from a fair argument, and check your own drafts and sources. Unit Thirty-One brings the analysis skills together on whole arguments.