Critical Thinking Cheat Sheet: Lesson 6 - Analyzing Arguments
Argument Components
Component | Description | Example |
Premises | Statements offered as reasons or evidence | “All humans need oxygen to survive.” “Sophia is a human.” |
Conclusion | Statement the argument is trying to establish | “Therefore, Sophia needs oxygen to survive.” |
Assumptions | Unstated beliefs connecting premises to conclusion | “The conditions that apply to all humans apply to Sophia specifically.” |
Deductive vs. Inductive Arguments
Type | Description | Example | Evaluation Criteria |
Deductive | Premises provide complete support for conclusion; if premises are true, conclusion must be true | “All mammals have hearts. Dogs are mammals. Therefore, dogs have hearts.” | Validity and Soundness |
Inductive | Premises provide partial support; make conclusion likely but don’t guarantee it | “Every swan I’ve seen has been white. Therefore, all swans are white.” | Strength and Cogency |
Evaluating Deductive Arguments
Validity: Does the conclusion follow logically from the premises? - Valid: If premises were true, conclusion would have to be true - Invalid: Conclusion doesn’t follow logically, even if premises are true
Soundness: Is the argument valid AND are all premises actually true? - Sound: Valid structure with true premises - Unsound: Either invalid structure or at least one false premise
Evaluating Inductive Arguments
Strength: How probable is the conclusion given the premises? - Strong: Premises make conclusion highly probable - Weak: Premises provide little support for conclusion
Cogency: Is the argument strong AND are all premises actually true?
Common Argument Patterns
Pattern | Structure | Example |
Modus Ponens | If P, then Q. P is true. Therefore, Q is true. | “If it’s raining, the ground is wet. It is raining. Therefore, the ground is wet.” |
Modus Tollens | If P, then Q. Q is false. Therefore, P is false. | “If she missed the train, she would be late. She wasn’t late. Therefore, she didn’t miss the train.” |
Disjunctive Syllogism | Either P or Q. Not P. Therefore, Q. | “Either the butler or gardener committed the murder. The butler didn’t do it. Therefore, the gardener did it.” |
Argument from Analogy | A is similar to B. A has property X. Therefore, B probably has property X. | “Earth and Mars are similar planets. Earth had conditions for life. Therefore, Mars might have had conditions for life.” |
Tips for Constructing Better Arguments
- Clarify your conclusion before building your argument
- Gather strong, relevant premises that directly support your conclusion
- Check for hidden assumptions and evaluate whether they’re reasonable
- Consider and address potential counterarguments
- Use appropriate reasoning type (deductive or inductive) for your context
- Avoid logical fallacies in your reasoning
Remember
Understanding argument structure helps you not only evaluate others’ arguments but also build stronger ones yourself. The goal isn’t to “win” debates but to engage more thoughtfully with ideas.