Page 247 - Between One and Many The Art and Science of Public Speaking

214 Part 3 Putting Theory Into Practice

diffi cult to fi nd. In using sign reasoning, show how reliable such signs have been
in the past. For example, in persuading students of the value of a college degree,
we can point to evidence from countless surveys showing that having a college
degree is associated with a higher lifetime income. It is important, however, to
rule out confl icting signs for an audience. Some people question the correlation
between college degrees and income by pointing out that those from affl uent
families are more likely to go to college in the fi rst place. Thus the higher in-
come later in life might be more a matter of greater family resources, not simply
getting a college degree. Unless a sign is infallible, most sign reasoning at best
indicates the probability that a claim is true.

Summary

There are three basic types of claims:
www.mhhe.com/brydon6
• Claims of fact deal with statements that are verifi able.
To evaluate your understand-
ing of this chapter, visit our • Claims of value deal with statements about right or wrong, good or bad,
Online Learning Center Web
site for quizzes and other moral or immoral.
chapter study aids.
• Claims of policy state that something should be done.
Many types of grounds are effective in supporting speeches:

• Examples should be relevant, of suffi cient quantity, and typical, and without
counterexamples.
• Facts should be from a reliable source, verifi able, recent, and consistent with
other known facts.
• Numerical data should be from a reliable and unbiased source, based on fair
questions, from a representative sample. Polls should report the sample size
and margin of error. Know what percentages are based on and whether the
mean or median is being cited.

• Expert opinion should come from a subject matter expert who is reliable and
unbiased.
• Explanations should be clear and accurate.

• Descriptions should be accurate and vivid.
• Narratives should have probability (coherence) and fi delity for the audience.
Five basic types of warrants link grounds and claims:

• Authority warrants assert that the opinions of the experts quoted are reliable
and valid to support the claim being made.

• Generalization warrants either establish a general rule based on specifi c
instances or apply an accepted generalization to a specifi c instance.
• Comparison (analogy) warrants assert that two things are similar to each
other and that what is true of the well known is also true of the less known.

8/24/07 3:20:58 PM
M4344.indb 214
M4344.indb 214 8/24/07 3:20:58 PM