Making Logical Technical Arguments

The Cain Project in Engineering and Professional Communication

ENGINEERING SERIES

What Do You Want to Assert?

• What situation involves a debatable point or a

question to be resolved? – An argument is a process of resolving a question about

which reasonable people might disagree.

• What claim has your analysis led you to assert?

• What will it take to convince your classmates or

professor? – What evidence, methods, or models do they expect?

– What conventions must you follow to win approval?

Argue to Expand Your Listeners’ Understanding• Present from general to

specific

• Build on what they know

• Don’t rehearse your own work process; instead, support your conclusions

• Use diagrams, graphs, and other visuals

• Keep visuals appropriate and simple

• Label key elements

• Tell audience what to notice

How Much Must Be Said?

• Persuasive arguments– Briefly express what audience already accepts

or knows– Extensively set forth the models or assumptions,

evidence, and limitations with which the audience is unfamiliar or opposes

– Focus on key decision factors

Recognize the Argument Challenge

• Engineering arguments often combine conceptual and action claims

• Scientific arguments often argue for what is or how it works, not what should be done

• Purpose affects how much you want to say about your evidence

Two Relevant Types of Arguments

• Pragmatic Argument (Advocates action that should be taken)

• Conceptual Argument (Defines or interprets the issue)

What Is Key to Reaching Agreement?

• What the issue is or means

• Showing the evidence fits a definition is key

• For example, meeting state regulatory requirements

• What should be done

• Proving the recommendation will produce the effects or benefits is usually the key

• Evidence and calculations, model necessary

Toulmin Argument Model

Claim Reasons

Limits

DefinitionsWarrantsAssumptions

Definitions

Evidence

Argument must “voice” all the arrows, showing connections between claim and reasons,principles and evidence, limits to claim.

Based on Williams, J. & Columb, G. The Craft of Argument, concise ed. New York: A.B.Longman (2003), pp. 77-86, 130-145.

Where Does the Audience Not Already Agree? Focus There.

• Definitions• Evidence• Reasons• Warrants• Limits

• Support the argument where agreement is missing.

• Example: – Emissions policy is “unreasonable.” – Companies located outside Houston’s city

limits should not be subject to emission limits.

– No jurisdiction beyond city boundaries– No penalties unless evidence of harm.

Why?

Where company located not controversial

What does “unreasonable”

mean?

Warranting Claims and Reasons

• Warrants are the justifying principles or generalizations

• Always imply two parts– General circumstance– Conclusion that can be inferred

• General warrant form: Whenever X, then Y

– Whenever authority is absent, others slack off.

– When the cat’s away, the mice will play.

– When the Mr. B is absent, Bob works less.

Guide for Stating Warrants

• Do readers know the warrant already?

• Will all readers think it’s true?

• Will they think it applies to this evidence?

• If they think it’s true and applicable, will they think it appropriate to their company or community?

Claims Linked to Evidence by Warrants (beliefs)

Claim: People who sing “Happy Birthday” should not have to pay royalties.

• Evidence: – Melody except for one eighth

note was published in 1893 for song: “Good Morning to All”

– Versions of Birthday Song published without copyright notice before 1934

– Hill family wins infringement suit and registers copyright in 1935 for “Happy Birthday.”

Possible Warrants:• When a tune was

published before 1909, its copyright has expired.

• When a work is in the public domain, it cannot be copyrighted.

• Whether a work is registered does not affect copyright.

Foreground Logic

• First sentences of each section should tie new or additional claims to the main claim.

• Major assumptions, generalizations, definitions, and specific evidence must all be related.

• Show the connections between principles and evidence.

• Have key equations or calculations to support generalizations.

Example of Deciding Whether to State Warrants Explicitly

CLAIM: Client should not expand plant to produce acetone.

REASON: Acetone prices are low; can purchase more cheaply than produce on site.

WARRANT: When product can be purchased at same or lower cost, don’t invest capital to produce it.

• Do readers know the warrant already? Common sayings test

– No common sayings

• Will all readers think warrants are true?

– Yes

• Will they think it applies to this evidence?

– Yes

• If they think it’s true and applicable, will they think it appropriate to their community?

– Yes, unless a price rise is expected, a supply likely to be interrupted, or the quality is uncertain (limits on the claim).

Limits to claim

State Warrants in Power Positions

• Establish controversial warrants BEFORE you offer claims and reasons.

• EXAMPLE: In any country that has signed the Berne Convention, the copyright is good for 50 years after the death of the author who created an original work after 1909 and published it with the copyright notice attached. One might think that well-loved children’s songs, such as “Happy Birthday,” aren’t subject to copyright, but it all depends on whether the composer met these tests.

• State traditional, well accepted warrants AFTER the claims and evidence.

State Warrants in Strategic Positions

• Establish controversial warrants BEFORE you offer claims and reasons.

• State traditional, well accepted warrants AFTER the claims and evidence.– Use accepted warrants for punch or flourish, not crucial support.

• Example: “After all, you can’t make an omelet without breaking eggs.”

– High school essays tend to open unnecessarily with warrants that are not controversial. Avoid such as the following in college papers or business reports:

• The industry has changed a great deal since it began.• Selecting the proper option is difficult.

What Details Make Your Argument Understandable?

Types of support material– Your analysis of statistics– Published findings of other

researchers– Examples– Expert testimony

Criteria for evaluating sources– Relevant to primary questions?– Recent?– Credible?– Biased?

Organizing Your Argument

• State the claim• Organize materials to answer questions in sequence

important to audience• Decide how much evidence must be shown• Place warrants - before or after evidence?• Choose where to respond to others• Place background, definitions, and concepts

strategically.

What Engineering Readers Expect

A TWO-PART STRUCTURE

Summary

Briefly: Situation, problem/task, importance, your responsibilities,

your actions, conclusions, recommendations

Discussion

Organized to answer questions in the order audience’s field

usually uses: Explains background, analyzes problem, proposes

solutions, expresses conclusion in detail (perhaps with

implementation details, etc.)

How to Allocate Space or Length

• Briefly discuss– Areas or points of agreement first

– Principles behind points of agreement briefly

• Spend more time on – Calculations and evidence that support pragmatic

portion (what should be done)

– Areas of disagreement or uncertainty

– Add definitions if audience contains decision-makers who are not engineers.

Choose Patterns Audience Knows to Help Them Listen Better

• Problem-solution organization– Describe the problem using engineering models and terms– Analyze evidence with engineering methods– Describe your proposed solution– Explain how your solution will fix the problem

• Topic or questions organization– Group information into different topic or question categories

• Chronological organization– Follow a time sequence (mostly progress reports)

Send Accessibility Signals to Remind Audience of Organization

• Signaling organization means indicating– How the talk is organized– Where different issues and questions will be

discussed– Where the speaker is in at a given moment in the

overall talk– Repeating key terms and patterns (parallelism)

• Reminding listeners of the organization shows speaker is responsive to their needs

Accessibility Signals

Set up audience expectations with your title, statement of purpose, transition statements, and visual aids.

Title: "A Cost-Effective Two-Stage Flood Control Program for Bexar County”

Common Purpose Statement: A two-stage program will minimize land acquisition costs and spread construction expenses.

Transition Statements:

Stage One: Establish infiltration zones and central drainage paths at pre-development costs to reduce future expense.

Stage Two: To delay costs, construct substations and storms sewers only as expansions require them.

“In Conclusion”: Pull It All Together

• Signal the end

• Summarize points

• Remind audience of compelling support

• Tie professional and motivating reasons to points

• In oral presentations, deliver your memorized final

sentence looking at the audience (no lame “I guess that’s all.”)

More resources are available for you

• under “Engineering Communication” at Connexions at http://cnx.org

• at the Cain Project site at http://www.owlnet.rice.edu/~cainproj

• in your course Communication Folder in OWLSPACE.

Lead through Excellence in Engineering Communication