Key Concepts in Argumentation and Logical Fallacies for Critical Thinking

Argument

A means of understanding other people's ideas and your own—not a win/lose debate.

Claim

A position or opinion about a topic that is arguable, not just a fact.

Claims of fact

Asserts that something is true or not true, based on definition, classification, or inference.

Claim of value

Argues that something is good/bad, right/wrong, desirable/undesirable.

Claim of policy

Proposes a change in action, attitude, or viewpoint.

Closed thesis statement

States the main idea and previews major points—useful for shorter essays.

Open thesis statement

States main idea but not all points—better for longer essays.

Relevant evidence

Applies directly to the argument and its claim.

Accurate evidence

Comes from credible, unbiased sources and is represented fairly.

Logical fallacy

A weakness or error in reasoning that disconnects claim and evidence.

Ad hominem fallacy

Attacking the person instead of the issue.

Faulty analogy

Comparing two things that aren't truly comparable.

Straw man fallacy

Misrepresenting an argument to make it easier to attack.

Either/or (false dilemma)

Presenting two extreme options as the only choices.

Hasty generalization

Not enough evidence to support a conclusion.

Circular reasoning

Repeating the claim instead of providing evidence.

Stacking the deck

Showing only one side of an argument.

Appeal to false authority

Using a non-expert as an expert.

Bandwagon appeal (ad populum)

Arguing something is good because 'everyone's doing it.'

First-hand evidence

Based on personal experience, anecdotes, or observation; appeals to pathos.

Second-hand evidence

Based on research or expert sources; appeals to logos.

Deductive argument

Starts with a general principle (major premise) and applies it to a specific case.

Inductive argument

Uses specific examples to reach a general conclusion.

Syllogism

A logical structure with a major premise, minor premise, and conclusion.

Enthymeme

A syllogism missing an explicit premise; only strong if the warrant is shared and supported.

Toulmin Model purpose

Helps structure arguments and uncover assumptions (warrants).

Claim (Toulmin)

The assertion being made.

Data / Grounds

The evidence or reasons supporting the claim.

Warrant

The shared assumption connecting evidence to claim.

Backing

Extra data or reasoning to strengthen the warrant.

Reservation

Conditions under which the claim might not hold true ('unless...').

Rebuttal

Acknowledges and responds to objections.

Qualifier

Limits or softens the claim (e.g., 'usually,' 'probably,' 'most likely').

They say

Represents the ideas or opinions of others you are responding to.

Disagreeing template

'I disagree that ___ because ___.

Agreeing template

'I agree that ___ because ___.

Qualifying template

'Yes (under this condition), but no (under this condition).

Argument FRQ outline (summary)

Thesis → Reasons + evidence + counterarguments → Conclusion (why it matters).

FRQ audience expectations

Use formal tone, be clear and organized, avoid bias, and bring fresh examples.