THE LOGICAL STRUCTURE
OF ARGUMENTS
Finding Reason in Madness
Formal Logic vs. Real World Logic
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Unfortunately, this is not a “logic” class of the
philosophical type, where there are certainties.
For example, in formal logic, “If all Ps are Qs, and if R
is a P, then R is a Q.”
That’s pretty defined, and very abstract. Our arguments
are…messier.
To wit:
P=Behaviors constituting sexual harassment
Q=Actions that justify dismissal from employment
R=Telling off-color jokes.
You put it together!
Formal Logic vs. Real World Logic
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This makes a certain logical sense, but not for everyone.
We might modify in some ways—telling off-color jokes
isn’t ALWAYS sexual harassment. But in certain
circumstances…
In short, we would need more information than the
purely logical argument would provide.
We can’t simply say things like ALL Rs are Ps, or that
every instance of P results in Q.
Hence, consider yourself discouraged from using words
like “prove.” We’re not proving anything. At best, we
hope to strengthen the resolve of those who agree, or
weaken the resolve of those who don’t.
The Role of Assumptions
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Our arguments are not grounded in abstract, catchall statements.
Instead, grounded in beliefs, assumptions, or values
granted by your audience.
As long as assumptions are shared, they can remain
unstated. If not shared, well, we have an issue.
Revisiting Women in Combat Roles
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Reason: “Women should be allowed to join combat
units because the image of women in combat would
help eliminate gender stereotypes.”
Seems like a sound, plausible point to argue.
But what ASSUMPTION does this argument depend
on? What is unstated?
Revisiting Women in Combat Roles
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The assumption at play is one that gender
stereotypes are harmful and we would be better
off without them.
But what if a person believed those roles were
biologically based? Divinely intended? Culturally
essential?
What if a person believes we should fight to
maintain them, and not dismiss them?
The argument is at risk if the assumption isn’t dealt
with.
The Enthymeme
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An enthymeme is an incomplete logical structure,
indicating that the argument requires something else
to be complete.
Comes from the Greek en (in) thumos (mind)
The argument is only persuasive if the audience
accepts the missing/unstated assumption
Enthymeme example
Summing Up
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Claims are supported by reasons. Usually, these
reasons can be expressed as because clauses.
A because clause attached to a claim is an
incomplete logical structure known as an Enthymeme.
To complete the structure, underlying assumptions
must be clarified.
To be effective, this underlying argument should be
a belief, value, or principle the audience grants.
Thinkin’ About It
The Toulmin System
Toulmin--a philosopher who dismissed classical logic
models in favor of a “courtroom” model based
around audience.
His model assumes:
1.
All assertions and assumptions are contestable by
“opposing counsel”
2.
All final “verdicts” about the persuasiveness of
opposing arguments will be given by a neutral
third party (a judge or jury)
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Toulmin’s Model
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Forces us to keep the opposition in mind,
anticipating their counter arguments and questions.
Considering a third party judge or jury reminds us
to answer opposing arguments fully, without anger,
and to present POSITIVE reasons for supporting our
case, and negative reasons for disbelieving the
opposing case.
Most importantly, keeps us from constructing an
argument for people who already agree with you.
Warrants
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WARRANTS are Toulmin’s term for underlying
assumptions.
Derived from the concept of the “warranty” or
“guarantee.” Basically, the warrant is the guarantee
of the argument’s soundness.
You may already use this term—for example, if
you’ve ever said “That’s an unwarranted conclusion.”
It indicates that you’ve overstepped your logical
situation without cause. There’s nothing to justify that
statement or move.
Grounds and Backing
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Alright—so we have a logical structure forming.
An Enthymeme (a claim with a because clause)
A Warrant (articulating our assumptions)
That great!
But, we need more. Lots more. These are just
statements. The BONES of an argument.
According to Toulmin, we need GROUNDS and
BACKING in order to “flesh out” our argument for
the masses.
Grounds
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Grounds are supporting evidence that cause an
audience to accept your reason.
Can be facts, data, stats, casual links, testimony,
examples, anecdotes.
These provide the meat on your bones.
IN the courtroom example, it’s “what you have to go
on”—the stuff you can point to and present to a
jury.
Let’s take a look.
An Enthymeme with Grounds
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In many cases, this is all you need for a successful
argument.
However—what if the audience rejects your assumption?
Backing
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BACKING is the argument that supports the
WARRANT.
May only require one or two sentences, but could
need to be a major component of your argument.
A Resistant Audience
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Often, a resistant audience will offer REBUTTALS—
attacks and counterarguments on your assertions.
But, these rebuttals are good—they remind us to
look at our arguments from the perspective of a
skeptic.
The best writers will plan for them, anticipate them,
and counter them before the arise.
The Qualifier
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Toulmin’s final term—QUALIFIER—serves to limit the
force of a claim, indicating a degree of probable truth.
Serves to remind us of our inability to “prove” anything.
Can be phrases/terms like “very likely,” “probably,”
“maybe.”
EXAMPLE: “Except in rare cases, women should not be
allowed in combat units.” Or, “With full awareness of
the potential dangers, I suggest we consider the option
of legalizing drugs as a way of ending the ill effects of
the black market.”
Remember that no argument is 100% persuasive.
Using Toulmin’s Schema
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Working individually or in small groups, imagine
that you have to write arguments developing the six
enthymemes previously discussed. Use the Toulmin
schema to help you determine what you need to
consider when developing each enthymeme. We
suggest that you try a four-box diagram structure
as a way of visualizing the schema. Here’s the
Toulmin schema applied to the first enthymeme: We
shouldn’t elect Joe as committee chair because he is
too bossy.”
Power of Audience-Based Reasons
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Both Aristotle and Toulmin support the need to
create “audience-based reasons.”
Whenever you consider a piece of persuasive
writing, you must couple that with the question
“persuasive to whom?”
A good reason to you may not be a good reason to
others.
Thusly, we can have two types of reasons: writerbased and audience-based.
The Difference
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Audience: an environmentalist conference
The government should build a dam on the Rapid
River because the only alternative power sources
are coal-fired or nuclear plants, both of which pose
greater risk to the environment than a hydroelectric
dam.
2. The government should build a hydroelectric dam
on the Rapid River because this area needs cheap
power to attract heavy industry.
Another Example
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Gordon, a former contractor, who wishes to be
exempted from his University’s algebra
requirements.
A Problem
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Gordon’s assertion that Algebra will not be useful in
his chosen field flies in the face of his intended
audience—a group of professors, most of whom
believe and practice “liberal education.” It’s a key
belief/value they all share, and walking on it will
cause the argument to fail.
How could he have been more persuasive?
A Better Approach
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“I should be exempted from the algebra
requirement because my experience as a contractor
and inventor has already provided me with
equivalent mathematical knowledge.”
Drops references to algebra’s “uselessness”
Honors the faculty’s values and their fear of setting
a bad precedent for other students.