Philosophy

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Here’s a clean, simple breakdown of everything you should study from Chapters 3, 5, and 6 of The Power of Critical Thinking (5th Canadian Edition), with examples where helpful.

CHAPTER 3: Making Sense of Arguments

Key Concepts to Know

  • Argument: A group of statements where some (premises) support another (conclusion).

  • Premise: A reason/evidence offered in support.

  • Conclusion: The main claim being supported.

How to Identify Arguments

  • Look for indicator words:

    • Premise indicators: because, since, given that, for, assuming that

    • Conclusion indicators: therefore, thus, so, hence, it follows that

Types of Arguments

  • Deductive: Claims the conclusion follows with certainty

  • Inductive: Claims the conclusion follows with probability

Common Argument Forms

  • Valid Deductive Forms:

    • Modus Ponens: If A, then B. A. → B.

    • Modus Tollens: If A, then B. Not B. → Not A.

    • Disjunctive Syllogism: A or B. Not A. → B.

  • Invalid Forms:

    • Affirming the Consequent: If A, then B. B. → (Invalid)

    • Denying the Antecedent: If A, then B. Not A. → (Invalid)

Argument Diagrams

(Visual breakdown of structure)

CHAPTER 5: Faulty Reasoning (Fallacies)

Fallacies of Irrelevant Premises

  • Genetic Fallacy: Dismissing a claim based on its origin.

  • Ad Hominem (Appeal to the Person): Attacking the person, not the argument.

  • Appeal to Popularity: “Everyone believes it, so it’s true.”

  • Appeal to Tradition: “It’s always been done this way.”

  • Appeal to Ignorance: “No one has proven it false, so it must be true.”

  • Appeal to Emotion: Using feelings instead of logic.

  • Red Herring: Distracting with an unrelated topic.

  • Straw Man: Misrepresenting an argument to attack it easily.

Fallacies of Unacceptable Premises

  • Begging the Question: Circular reasoning.

  • False Dilemma: Only two options are presented when more exist.

  • Slippery Slope: Claiming one small step will lead to an extreme.

  • Hasty Generalization: Drawing a conclusion from too little evidence.

  • Faulty Analogy: Assuming that because two things are alike in one way, they’re alike in all ways.

CHAPTER 6: Deductive Reasoning – Categorical Logic

Key Terms

  • Categorical Statement: Statement relating two categories (e.g., All A are B)

  • Standard Forms:

    • A: All S are P (Universal Affirmative)

    • E: No S are P (Universal Negative)

    • I: Some S are P (Particular Affirmative)

    • O: Some S are not P (Particular Negative)

Quantifiers

  • Words like all, some, no — determine type of statement.

Venn Diagrams

  • Used to test validity of categorical syllogisms:

    • Step 1: Diagram both premises

    • Step 2: See if conclusion is visually supported

Syllogism Validity

  • A syllogism = 2 premises + 1 conclusion.

  • Must be in standard form to test with Venn diagrams.