Video: How does understanding whether or not an argument is inductive or deductive help me?

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1 Page 1 of 10 10b Learn how to evaluate verbal and visual arguments. Video: How does understanding whether or not an argument is inductive or deductive help me? Download transcript Three common ways to analyze verbal and visual arguments are (1) to concentrate on the type of reasoning the writer is using; (2) to question the logical relation of a writer s claims, grounds, and warrants, using the Toulmin method; and (3) to examine the ways an argument appeals to its audience. 1. Recognizing types of reasoning Writers of arguments may use either inductive or deductive reasoning. When writers use inductive reasoning, they do not prove that the statements that make up the argument are true; instead they convince reasonable people that the argument s assertion is probable by presenting evidence (facts and statistics, telling anecdotes, and expert opinions). When writers use deductive reasoning, they claim that a conclusion follows necessarily from a set of assertions, or premises if the premises are true and the relationship between them is valid, the conclusion must be true. Consider the following scenarios. Inductive reasoning A journalism student writing for the school newspaper makes the following claim. As Sunday s game shows, the Philadelphia Eagles are on their way to the playoffs. Reasoning inductively, the student presents a number of facts her evidence that support her claim but do not prove it conclusively. Page 193 A reader would evaluate this student s argument by judging the quality of her evidence, using the criteria listed in the box above.

2 Page 2 of 10 Inductive reasoning is a key feature of the scientific method. Scientists gather data from experiments, surveys, and careful observations to formulate hypotheses that explain the data. They then test their hypotheses by collecting additional information. NAVIGATING THROUGH COLLEGE AND BEYOND Assessing Evidence in an Inductive Argument Is it accurate? Make sure that any facts presented as evidence are correct and not taken out of context. Is it relevant? Check to see if the evidence is clearly connected to the point being made. Is it representative? Make sure that the writer s conclusion is supported by evidence gathered from a sample that accurately reflects the larger population (for example, it has the same proportion of men and women, older and younger people, and so on). If the writer is using an example, make sure that the example is typical and not unique. Is it sufficient? Evaluate whether there is enough evidence to satisfy questioning readers. Deductive reasoning The basic structure of a deductive argument is the syllogism. It contains a major premise, or general statement; minor premise, or specific case; and conclusion, which follows when the general statement is applied to the specific case. Suppose the journalism student were writing about historically great baseball teams and made the following argument. Page 194 This is a deductive argument: if the relationship between its premises is valid and both premises are true, the conclusion must be true. The conclusion follows from the premises. For example, it is not accurate to say: The train is late. Jane is late. Therefore, Jane must be on the train. Jane could be late because her car broke down. However, if the train is late and Jane is on the train, Jane must be late. If the logical relationship between the premises is valid, a reader must evaluate the truth of the premises themselves. Do you think, for example, that the number of World Series wins is a proper measure of a team s greatness? Or the only measure? If not, you could claim that the major premise is false or suspect and does not support the conclusion.

3 Page 3 of 10 Deductive reasoning predominates in mathematics and philosophy and some other humanities disciplines. However, you can use both types of reasoning in college courses and in life. Inductive or Deductive Reasoning (Your score will be reported to your instructor) 2. Using the Toulmin method to analyze arguments Video: When does it make sense for me to use Toulmin to evaluate an argument? Download transcript Philosopher Stephen Toulmin s analysis of arguments is based on claims (assertions about a topic), grounds (reasons and evidence), and warrants (assumptions or principles that link the grounds to the claims). Consider the following sentence from an argument by a student. The death penalty should be abolished because if it is not abolished innocent people could be executed. This example, like all logical arguments, has three facets. 1. The argument makes a claim. Also known as a point or a thesis, a claim makes an assertion about a topic. A strong claim responds to an issue of real interest to its audience in clear and precise terms. It also allows for some uncertainty by including qualifying words such as might or possibly, or describes circumstances under which the claim is true. A weak claim is merely a statement of fact or a statement that few would argue with. Because personal feelings are not debatable, they are not an appropriate claim for an argument. Page The argument presents grounds for the claim. Grounds consist of the reasons and evidence (facts and statistics, anecdotes, and expert opinion) that support the claim. As grounds for the claim in the example, the student would present statistics and stories related to innocent people being executed. The box below should help you assess the evidence supporting a claim. 3. The argument depends on assumptions that link the grounds to the claim. When you analyze an argument, always look for the unstated assumptions, or warrants, that underlie both the claim and the grounds that support it. The warrants underlying the example argument

4 Page 4 of 10 against the death penalty include two ideas: (1) it is wrong to execute innocent people; and (2) it is not possible to be completely sure of a person s guilt. Warrants differ from discipline to discipline and from one school of thought to another. If you were studying the topic of bullfighting and its place in Spanish society in a sociology course, for example, you would probably make different arguments with different warrants than would the writer of a rhetorical analysis of Ernest Hemingway s book about bullfighting, Death in the Afternoon. You might argue that bullfighting serves as a safe outlet for its fans aggressive feelings. Your warrant would be that sports can have socially useful purposes. A more controversial warrant would be that it is acceptable to kill animals for entertainment. Page 196 As you read the writing of others and as you write yourself, look for unstated assumptions. What does the reader have to assume to accept the reason and evidence in support of the claim? Hidden assumptions sometimes show bias, positive or negative inclinations that can manipulate unwary readers. Assumptions also differ across cultures. TYPES OF EVIDENCE FOR CLAIMS Facts and statistics: Relevant, current facts and statistics can persuasively support a claim. People on different sides of an issue can interpret the same facts and statistics differently, however, or can cite different facts and statistics to prove their point. Facts don t speak for themselves: they must be interpreted to support a claim. Anecdotes: An anecdote is a brief narrative used as an illustration to support a claim. Because stories appeal to the emotions as well as to the intellect, they can be very effective. Be especially careful to check anecdotes for logical fallacies (see pp ). Though useful, anecdotes should be only one of the types of evidence you use. Expert opinion: The views of authorities in a given field can also be powerful support for a claim. Be sure that the expert cited has credentials related to the topic. 3. Analyzing appeals Video: How does analyzing the appeals help me to understand an argument better? Download transcript Arguments support claims by way of three types of appeals to readers, categorized by the Greek words logos (logic), pathos (emotions), and ethos (character): Logical appeals offer facts, including statistics, as well as reasoning, such as the inductive and deductive arguments on pages Emotional appeals engage an audience s feelings and invoke beliefs that the author and audience share. Ethical appeals present authors as fair, reasonable, and trustworthy, backed up with the testimony of experts.

5 Page 5 of 10 Most arguments draw on all three appeals. A proposal for more nutritious school lunches might cite statistics about childhood obesity (a logical appeal). The argument might address the audience s emotions by describing overweight children feasting on junk food available in the cafeteria (an emotional appeal). It might quote a doctor explaining that healthful food aids concentration (a logical appeal) and that all children deserve to have nutritious food available at school (an ethical appeal). When writing an argument, tailor the type and content of appeals to the specific audience you are addressing. For example, school administrators, charged with making decisions about cafeteria food, might be persuaded by statistics demonstrating the relationship of the cost of food to its nutritional value (logical appeal). 4. Avoiding fallacies Video: Why are fallacies important? Download transcript In their enthusiasm to make a point, writers sometimes commit fallacies, or mistakes in reasoning. Fallacies also can be understood as misuses of the three appeals. Learn to identify fallacies when you read and to avoid them when you write. Page 197 Logical fallacies These fallacies involve errors in the inductive and deductive reasoning processes discussed in the preceding section: Non sequitur: A conclusion that does not logically follow from the evidence or one that is based on irrelevant evidence. Generalizing based on evidence is an important tactic of argument. However, the evidence must be relevant. Non sequiturs also stem from dubious assumptions. False cause or post hoc: An argument that falsely assumes that because one thing happens after another, the first event was a cause of the second event. Although writers frequently describe causes and effects in argument, fallacies result when writers assume a cause without providing evidence. Self-contradiction: An argument that contradicts itself.

6 Page 6 of 10 Circular reasoning: An argument that restates the point rather than supporting it with reasonable evidence. Begging the question: A form of circular reasoning that assumes the truth of a questionable opinion. Some claims contain assumptions that must be proved. Does the President in fact have a poor relationship with the military? Page 198 Hasty generalization: A conclusion based on inadequate evidence. Sweeping generalization: An overly broad statement made in absolute terms. When made about a group of people, a sweeping generalization is a stereotype. Legitimate generalizations must be based on evidence that is accurate, relevant, representative, and sufficient (see the box on p. 195). Either/or fallacy: The idea that a complicated issue can be resolved by resorting to one of only two options when in reality there are additional choices. Frequently, arguments consider different courses of action. Authors demonstrate their sense of fairness and their understanding of issues by considering a range of options. Ethical fallacies These fallacies undermine a writer s credibility by showing lack of fairness to opposing views and lack of expertise on the subject of the argument:

7 Page 7 of 10 Ad hominem: A personal attack on someone who disagrees with you rather than on the person s argument. This fallacy stops debate by ignoring the real issue. Page 199 Guilt by association: Discrediting a person because of problems with that person s associates, friends, or family. This tactic undermines an opponent s credibility and is based on a dubious assumption: if a person s associates are untrustworthy, that person is also untrustworthy. False authority: Presenting the testimony of an unqualified person to support a claim. Expert testimony can strengthen an argument, as long as the person cited is an authority on the subject. This fallacy frequently underlies celebrity endorsements of products. Emotional fallacies These fallacies stir readers sympathy at the expense of their reasoning: False analogy: A comparison in which a surface similarity masks a significant difference. Analogies can enliven an argument and deepen an audience s understanding of a subject, provided the things being compared actually are similar. Bandwagon: An argument that depends on going along with the crowd, on the false assumption that truth can be determined by a popularity contest.

8 Page 8 of 10 Page 200 Red herring: An argument that diverts attention from the true issue by concentrating on an irrelevant one. Identifying Fallacies (Your score will be reported to your instructor) 5. Reading visual arguments Video: How do I 'Read' a visual argument? Download transcript Like written arguments, visual arguments support claims with reasons and evidence, rely on assumptions, and may contain fallacies. They make logical appeals, such as a graph of experimental data; emotional appeals, such as a photograph of a hungry child; and ethical appeals, such as a corporate logo (see p. 196). Like all written works, visual arguments are created by an author to achieve a purpose and to address an audience within a given context. (See Chapter 1, pp ) Recall that Toulmin s system analyzes arguments based on the claims they make, the grounds (evidence and reasons) for those claims, and the warrants (underlying assumptions) that connect the grounds with the claims. (See the explanation of Toulmin analysis on pp ) While these elements function similarly in verbal and visual arguments, unstated assumptions play a larger role in visual arguments because we are not used to reading visuals and interpreting the implicitly stated claims and grounds. For example, consider a photograph of a politician with her family members. The image makes a claim (she is a good public servant) and implicitly offers grounds (because she cares for her family). The warrant is that a person s family life indicates how she will perform in office. This assumption may be false. Advertisements combine text and images to promote a product or message to an audience in a social context. They use the resources of visual design: type of image, position, color, light and shadows, fonts, and white space. (See the questions on previewing a visual in Chapter 7, p. 129, and the discussion of design in Chapter 6, pp ) The public-service ad in Figure 10.1 was developed by the nonprofit advocacy group Adbusters.

9 Page 9 of 10 FIGURE 10.1 A public-service argument: Adbusters public-service advertisement. The ad s text and design evoke a popular series of ads for a brand of vodka. Its uncluttered design focuses the viewer s attention on the shape of a bottle, the outline of which consists of chairs. The text at the bottom refers to AA: Alcoholics Anonymous. By association, the text and images in this publicservice ad remind readers that liquor can lead to alcoholism (and then to AA). In contrast with those it spoofs, this ad evokes an unexpected threat, creating a powerful emotional appeal. What claims do you think this ad makes? One might be alcohol is dangerous. The evidence is supplied by the reader s prior knowledge about alcoholism. The argument s assumptions include the viewer s familiarity with both the original liquor campaign and the initials AA for Alcoholics Anonymous. Page 201 Fallacies frequently occur in visual arguments. For example, celebrity endorsements of products rely on our respect for the celebrity s character. However, a photo of an athlete driving a particular type of car demonstrates false authority, unless the athlete also happens to be an expert on cars. (See p. 199.) Using Toulmin Analysis on Visuals (Your score will be reported to your instructor) CHECKLIST Reading Visual Arguments Critically Review the questions for previewing a visual from Chapter 7, page 129, and add the following: What can you tell about the visual s creator or sponsor? What seems to be the visual s purpose? Does it promote a product or message? What features of the visual suggest the intended audience? How? How do features of design such as the size and position of the elements, the colors, and the shapes of images affect the visual s message?

10 Page 10 of 10 What is the effect of any text, audio, or video that accompanies the visual?