Chapter 5
PERSUASION THROUGH
RHETORIC

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So far we’ve examined:
Two kinds of argument:
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Those trying to prove or demonstrate a conclusion 

Those trying to support a conclusion © 2012 McGraw-Hill Higher Educati

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Arguments that try to
DEMONSTRATE a conclusion include arguments like these:
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All As are Bs.
No Bs are Cs.
No As are Cs.

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If P then Q.
Not-Q.
Not-P.

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Arguments that try to
SUPPORT a conclusion include: 
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Generalizing
Reasoning by analogy Reasoning about cause and effect

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More about this later! © 2012 McGraw-Hill Higher Educati

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Real-life reasoning usually involves one or the other or both of these two basic forms of argument. © 2012 McGraw-Hill Higher Educati

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But there’s more to consider than just logic.

Take this argument…

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“It’s sick to torture an innocent creature, yet that’s exactly what these so-called scientists do when they perform hideous experiments on little puppies. Moral sadists!
They make me vomit! They’re no better than Hitler.”
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The argument is really just this:
Scientists who use dogs in experiments bring pain to innocent creatures. Therefore, they act immorally. © 2012 McGraw-Hill Higher Educati

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“It’s sick to torture an innocent creature, yet that’s exactly what these so-called scientists do when they perform hideous experiments on little puppies. Moral sadists! They make me vomit! They’re no better than Hitler.”

“Scientists who use dogs in experiments bring pain to innocent creatures, and thus act immorally.” The original phrasing seems more powerful.
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It COLORS the argument with words having strong psychological impact, or
“RHETORICAL FORCE”

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“It’s sick to torture an innocent creature, yet that’s exactly what these so-called scientists do when they perform hideous experiments on little puppies. Moral sadists!
They make me vomit! They’re no better than Hitler.”

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“Sick,” “Torture,”
“hideous,” “little puppies,”
“Hitler,” “vomit” etc. make us react emotionally.
The passage tries not merely to support a conclusion, but to SELL it.
It tries to PERSUADE us!
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RHETORIC is the art of
PERSUASION.
It differs from LOGIC, which seeks to establish a conclusion.

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Rhetoric uses the psychological (rhetorical) force of expressions to influence our attitudes.

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EXAMPLE:
Calling a scientist a “so-called” scientist suggests he/she is something less than a true scientist.
It DOWNPLAYS his/her credentials.

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Likewise, “little puppies” arouses a powerful compassionate response. It gives one a mental picture like this:

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NOTHING WRONG with trying to be persuasive or with using rhetoric to dress up or sell an argument.
Good writers choose words carefully, to make their writing persuasive. © 2012 McGraw-Hill Higher Educati

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But this is CRITICAL
THINKING!
It means not being SEDUCED by rhetoric.

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Interesting?
If you say that Alice DID NOT
MURDER HER MOTHER…
People form an unfavorable opinion of Alice!

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Even though there is no
REASON to do so.

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Being able to make wise decisions and reasonable and well-founded judgments…
…depends largely on our ability to “see through” rhetoric to evidence and argument.

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We should be able to do this:
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Distinguish between rhetoric and argument Be able to identify the more common forms of rhetoric

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Specifically, these:
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