cs 4001mary jean harrold 1 logical structure of arguments

Mary Jean Harrold 1CS 4001

Logical Structure of Arguments


Overview

Real-world argument not formal logic Difference between formal logic and real-world

argument Real-world argument

grounded in beliefs, assumptions, or values granted by the audience

these beliefs, assumptions, and values often unstated


Overview

What are examples of arguments in which beliefs, assumptions, and values are shared by audience and can remain unstated?


Overview

Consider argument “<you complete> ” What is underlying assumption of this argument? What is an enthymeme? Complete it by stating unstated assumption

Initial enthymeme: Claim: Stated reason: Unstated reason:


Overview

Consider argument “Rabbits make good pets because they are gentle” What is underlying assumption of this argument? What is an enthymeme? Complete it by stating unstated assumption

Initial enthymeme: “Rabbits make …gentle” Claim: “Rabbits make good pets” Stated reason: “Because they are gentle” Unstated reason: “Gentle animals make good pets.”


The Toulmin System

Enthymeme

An incomplete logical structure

Toulmin’s modelAll assertions and assumptions are contestable by “opposing

counsel”

All final “verdicts” about the persuasiveness of alternative arguments will be rendered by a neutral third party, a judge or jury.

Implications of Toulmin’s model for argument


The Toulmin System

EnthymemeAn incomplete logical structure

Toulmin’s model1. All assertions and assumptions are contestable by “opposing

counsel”2. All final “verdicts” about the persuasiveness of alternative

arguments will be rendered by a neutral third party, a judge or jury.

Implications of Toulmin’s model for argument Must anticipate counter arguments and question assumptions Must be fair in representing the other side Must make sure our argument is not constructed just for those

who already agree with us


The Toulmin System (cont’d)

ExampleInitial enthymeme: We should buy this used Volvo because it is extremely safeClaim: We should buy this used VolvoStated Reason: It is extremely safeUnstated Reason: because we should buy the car that is the safest

In Toulmin’s system, the unstated reasons are warrantsWarrant: The safest car is the best car



ExampleInitial enthymeme: We should buy this used Volvo because it is extremely safeClaim: We should buy this used VolvoStated Reason: It is extremely safeWarrant: The safest car is the best car

How do we support the reason and warrant?



ExampleInitial enthymeme: We should buy this used Volvo because it is extremely safeClaim: We should buy this used VolvoStated Reason: It is extremely safeWarrant: The safest car is the best car

How do we support the reason and warrant?Support stated reason with grounds (evidence, what you have to go on---facts, statistics, data, testimony, interviews, surveys, …)Support warrant with backing (for audience who may not share the unstated claim, why do you believe this, how do you know this…)



ExampleInitial enthymeme: We should buy this used Volvo because it is extremely safeClaim: We should buy this used VolvoStated Reason: It is extremely safe

Grounds: Warrant: The safest car is the best car

Backing:



ExampleInitial enthymeme: We should buy this used Volvo because it is extremely safeClaim: We should buy this used VolvoStated Reason: It is extremely safe

Grounds: Warrant: The safest car is the best car

Backing:

How do we address the resistant audienceConditions of Rebuttal:

Rebutting reasons and grounds Rebutting the warrant and backing

Qualifiersince cannot usually prove your argument, qualify it


Exercise

Use Toulmin’s scheme to help determine what you have to consider in developing the following enthymeme

Practicing Piano is good for kids because it teaches discipline


Audience-based Reasons


ISSUE QUESTION: Should it be legal for drivers to talk on cell phones while driving?

Audience: Your state political representativesClaim: Cell phones should be illegal to use while driving.Reason 1: because holding a cell phone in one hand diminishes drivers’ capacity

to control their cars physicallyGrounds: Find statistics showing how many drivers have had trouble making turns or staying in their lanes when talking on ca cell phone; statistics of number of accidents caused by cell phone usersWarrant: Anything that interferes with drivers’ ability to handle their cars is badBacking:

Conditions of Rebuttal for Reason 1: Cell phones have been shown to be valuable in road emergencies; many business people need cell phones to make contact with clients and need to save time by talking while they are driving; drivers use their hands to do a lot of other equally or more distracting things while driving, such as drinking coffee, reading, fiddling with CDs and tapes, shaving, putting on make-up; should these activities be banned too?

Qualifier: Except with a headset of speaker-phone, cell phones should be illegal to use while driving


Audience: Your state political representativesClaim: Cell phones should be illegal to use while driving.Reason 2:

Grounds: Warrant: Backing:

Conditions of Rebuttal for Reason 2 Qualifier:

ISSUE QUESTION: Should it be legal for drivers to talk on cell phones while driving?


Audience-based Reasons

Audience-based VS writer-based Discussion:

What is the warrant Will audience grant it?

1. Audience: a beleaguered parenta. I should be allowed to stay out until 2 A.M. because all my

friends do

b. I should be allowed to stay out until 2 A.M. because only if I’m free to make my own decisions will I mature


1. Who is your audience?

2. How much do they care about your issue?

3. What is your audience’s current attitude toward your issue?

4. What will be your audience’s likely objections to your argument?

5. What values, beliefs, or assumptions about the work do you and your audience share?

Who is Your Audience


What Will Be Your Audiences in the Next Five Years?

In each case, for what are you trying to argue?


What Will Be Your Audiences in the Next Five Years?

In each case, for what are you trying to argue?

1. A company where you want to get a job

2. A boss whom you want to convince about your project.

3. A project leader whom you want to convince about your design.

4. A customer whom you want to convince about your plan for developing their software.

5. A graduate school where you want to enroll.

6. A teacher whom you want to convince to pass you

cs 4001mary jean harrold 1 logical structure of arguments

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