1. Comparative Reasoning Think “This is Like That”
Chapter 12
Comparative Reasoning
Think “This is Like That”

2. Comparative, Ideological, and Empirical Inferences
Comparative reasoning (or this-is-like-that thinking) enables us to:
Make interpretations, draw inferences, or offer explanations by relying on something that is:
More familiar in order to understand something that is less familiar
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3. “This Is Like That”—Recognizing Comparative Reasoning
Gardens of Comparatives
People cultivate an exceptional variety of ways to express comparative reasoning
Most comparative reasoning doesn’t appear as a fully developed argument:
With reasons and claims
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4. “This Is Like That”—Recognizing Comparative Reasoning
Powerful Comparisons Connect Intellect and Emotion
Knowing that vivid comparisons can move hearts as well as minds, speechwriters:
Strive to associate their ideas with memorable comparisons as these next two examples illustrate
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5. Breaking Down Comparative Reasoning
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6. Evaluating Comparative Inferences
Do the Four Tests of Acceptability Apply?
First test
Are the premises all true?
Second test
Are there counterexamples and how difficult is it to imagine them?
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7. Evaluating Comparative Inferences
Third test
Are the premises relevant to the truth of the conclusion?
Fourth test
Does the truth of any premise depend on the truth of the conclusion?
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8. Evaluating Comparative Inferences
The purpose of comparative reasoning is to:
Illustrate, illuminate, suggest, or hypothesize, rather than to prove that a conclusion is true
Five Criteria for Evaluating Comparative Reasoning
Why is comparative reasoning so potentially valuable?
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9. Evaluating Comparative Inferences
If the comparison is reasonable, then some salient feature of the more familiar object is:
Also a salient feature of the less familiar object
Comparative inferences, including analogical arguments, are inductive and probabilistic
Familiarity
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10. Evaluating Comparative Inferences
Successful comparisons direct the listener’s attention to that which is more familiar
Simplicity
A measure of the relative complexity of the comparison
Simpler comparisons are often more readily understood and remembered
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11. Evaluating Comparative Inferences
Comprehensiveness
The virtue of simplicity must be balanced with the importance of comprehensiveness
Productivity
The capacity of a comparison to bring to mind unexpected new ideas that go:
Beyond the points of comparison initially mentioned
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12. Evaluating Comparative Inferences
Testability
The capacity of a comparison to project consequences that have:
The potential to be shown to be false, inapplicable, or unacceptable
The criterion of testability enables us to evaluate the acceptability of a proposed comparison
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13. Evaluating Comparative Inferences
Shaping Our View of the Universe for Two Thousand Years
The Many Uses of Comparative Inferences
Comparative reasoning is used in discussions of ethics:
Such as to compare cases and infer obligations
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14. Evaluating Comparative Inferences
The basic character of the appeal to precedent is the assertion that:
The case in question is so much like the prior case that the ruling that applied there should apply here
A comparison’s persuasive power depends heavily on the suggested parallelism
Simplicity and Hypothetical Entities
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15. © 2013 Pearson Education, Inc. All rights reserved.