CS212 Unit 7 Written English & Logical Fallacies Activity Notes

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Purdue University Global

CS212 Communicating Professionalism

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What You Should Know About Written English: Key Grammar Terms and Logical Fallacies

Written English relies on strong grammar, clear sentence structure, and logical reasoning. Understanding concepts such as clauses, conjunctions, phrases, rhetorical appeals, and logical fallacies helps writers communicate effectively, avoid common mistakes, and build persuasive arguments. This guide explains the most important terms with clear definitions and examples.

Understanding Logical Fallacies in Written English

Logical fallacies are errors in reasoning that weaken an argument. They often persuade readers emotionally instead of relying on sound evidence.

Ad Hominem

An ad hominem fallacy occurs when someone attacks the person making an argument instead of addressing the argument itself.

Example:
Instead of responding to a scientist’s research, someone dismisses the findings by criticizing the scientist’s personality.

Bandwagon Fallacy

The bandwagon fallacy assumes something is true simply because many people believe it.

Example:
“Everyone uses this study method, so it must be the best.”

Begging the Question

This fallacy occurs when an argument simply repeats its claim instead of providing evidence.

Example:
“The policy is effective because it works well.”

Either-Or Fallacy (False Dilemma)

The either-or fallacy presents only two choices when other valid options exist.

Example:
“You’re either with us or against us.”

Equivocation

Equivocation uses the same word with different meanings, creating a misleading conclusion.

False Analogy

A false analogy assumes that because two things share one similarity, they are similar in every way.

False Authority

A false authority fallacy relies on the opinion of someone who lacks expertise in the relevant subject.

Example:
An athlete giving medical advice outside their area of knowledge.

False Cause

This fallacy assumes that because one event happened before another, it caused the second event.

Example:
“I wore lucky socks, so our team won.”

Guilt by Association

This fallacy unfairly judges someone based on their relationship with another person or group.

Hasty Generalization

A hasty generalization draws a broad conclusion from limited or biased evidence.

Non Sequitur

A non sequitur is a conclusion that does not logically follow from the preceding statement.

Oversimplification

This fallacy ignores important details and reduces a complex issue to an overly simple explanation.

Red Herring

A red herring distracts readers by introducing an irrelevant issue instead of addressing the main argument.

Slippery Slope

The slippery slope fallacy claims that one action will inevitably lead to a chain of increasingly negative events without sufficient evidence.

Understanding Clauses

A clause is a group of words containing both a subject and a verb.

Independent Clause

An independent clause expresses a complete thought and can stand alone as a sentence.

Examples:

The pumps failed.
The ship sank.
Many passengers did not notice the collision.

Dependent Clause

A dependent clause (also called a subordinate clause) contains a subject and verb but cannot stand alone as a complete sentence. It usually begins with a subordinating conjunction.

Examples:

When the ship collided with the iceberg…
If the ship had struck the iceberg head-on…
Because the weather worsened…

Understanding Conjunctions

A conjunction connects words, phrases, or clauses.

Coordinating Conjunctions

These join words or clauses of equal importance.

Common coordinating conjunctions include:

Correlative Conjunctions

These conjunctions always work in pairs.

Examples include:

Both…and
Either…or
Neither…nor
Not only…but also

Subordinating Conjunctions

These connect dependent clauses to independent clauses.

Common examples include:

Because
Although
Since
When
While
If
Unless

Understanding Phrases

A phrase is a group of words that functions as one part of speech but does not contain both a subject and a verb.

Examples:

Through the hull
During the storm
After the collision

Phrases can function as nouns, adjectives, or adverbs within a sentence.

Understanding Modifiers

A modifier is a word or group of words that describes or limits another word, making writing more precise.

Example:

The extremely powerful engine.
The carefully written report.

Understanding Prepositions

A preposition shows the relationship between a noun or pronoun and another word in the sentence. These relationships often involve location, direction, time, or manner.

Common prepositions include:

About
Above
Across
Against
Along
Around
At
Before
Behind
Below
Beneath
Between
By
During
For
From
In
Into
Near
Of
On
Over
Through
To
Toward
Under
Until
Upon
With
Within
Without

Understanding Run-on Sentences

A run-on sentence occurs when two or more independent clauses are joined incorrectly without proper punctuation or conjunctions.

Incorrect:
The ship hit the iceberg, many passengers remained calm.

Correct:
The ship hit the iceberg, but many passengers remained calm.

Rhetorical Appeals in Writing

Persuasive writing often relies on three classical rhetorical appeals.

Ethos

Ethos appeals to credibility and trustworthiness. Writers establish authority by demonstrating expertise or reliability.

Logos

Logos appeals to logic through facts, statistics, evidence, and rational reasoning.

Pathos

Pathos appeals to the audience’s emotions to create empathy or inspire action.

Oxymoron

An oxymoron combines contradictory words to create emphasis or a memorable expression.

Examples include:

Deafening silence
Bittersweet
Poor little rich girl
Living dead

Why These Writing Concepts Matter

Strong writing combines grammatical accuracy with logical reasoning. Understanding these concepts helps writers:

Build clear and organized sentences.
Avoid common logical fallacies.
Create stronger persuasive arguments.
Improve academic and professional writing.
Communicate ideas with greater clarity and credibility.

Quick Reference Summary

Clause: A group of words containing a subject and a verb.
Independent Clause: A complete sentence.
Dependent Clause: Cannot stand alone.
Phrase: A group of words without both a subject and verb.
Modifier: Describes another word.
Preposition: Shows relationships of time, place, or direction.
Conjunction: Connects words, phrases, or clauses.
Ethos: Appeal to credibility.
Logos: Appeal to logic.
Pathos: Appeal to emotion.
Logical Fallacy: An error in reasoning that weakens an argument.

Frequently Asked Questions

What is a logical fallacy in writing?

A logical fallacy is an error in reasoning that weakens an argument. Rather than relying on evidence, fallacies often use misleading assumptions or emotional appeals.

What is the difference between an independent and a dependent clause?

An independent clause expresses a complete thought and can stand alone as a sentence. A dependent clause requires an independent clause to complete its meaning.

What are the three rhetorical appeals?

The three rhetorical appeals are:

Ethos: Credibility
Logos: Logic
Pathos: Emotion

These techniques help writers persuade their audience effectively.

What is the purpose of conjunctions?

Conjunctions connect words, phrases, and clauses to improve sentence flow and clarity.

Why are logical fallacies important to understand?

Recognizing logical fallacies helps readers evaluate arguments critically and enables writers to produce stronger, more credible content.

A clause is a group of words containing a subject and a verb. Independent clauses can stand alone as complete sentences, while dependent clauses require another clause to complete their meaning.

Logical fallacies are errors in reasoning that weaken arguments by relying on faulty logic instead of valid evidence.

Ethos, logos, and pathos are the three classical rhetorical appeals. Ethos builds credibility, logos appeals to logic, and pathos appeals to emotion.

Conjunctions connect words, phrases, and clauses. The three main types are coordinating, correlative, and subordinating conjunctions.

Run-on sentences occur when two or more independent clauses are joined incorrectly without proper punctuation or conjunctions.

References

American Psychological Association. (2020). Publication Manual of the American Psychological Association (7th ed.). https://apastyle.apa.org/

Lunsford, A. A. (2021). The St. Martin’s Handbook (9th ed.). Bedford/St. Martin’s. https://www.macmillanlearning.com/

Purdue Online Writing Lab. (n.d.). Grammar. https://owl.purdue.edu/owl/general_writing/grammar/