Induction, Deduction, and Logical Fallacies

Foundations of Reasoning: Induction and Deduction

  • Inductive Reasoning (Induction)

    • Looks for many individual examples and patterns to draw a general conclusion.
    • Operates from the bottom up, gathering specific evidence to establish broader claims.

  • Deductive Reasoning (Deduction)

    • Begins with general basic principles that lead directly to a conclusion about a specific case.
    • Operates from the top down, applying universal truths or established rules to particular instances.

Fallacies of Logic and Relevance

  • Non Sequitur Fallacy

    • Occurs when a conclusion or statement has no logical connection to the preceding premise or argument.
    • Represents a fundamental break in the chain of reasoning where the conclusion does not follow from what came before.

  • Red Herring

    • Involves misleading readers or an audience by distracting them from the main argument.
    • Classified explicitly as a specific type of non sequitur fallacy designed to divert attention to an irrelevant side issue.

  • Slippery Slope

    • Involves attacking an idea by claiming that it must inevitably lead to distant, extreme, or undesirable consequences without providing logical justification for each step in the chain.

Causal and Generalization Fallacies

  • False Cause / Post Hoc, Ergo Propter Hoc Fallacy

    • Latin translation: "after this, therefore because of this."
    • Faulty reasoning that assumes chronological succession establishes causation, concluding that because event B followed event A, event A must have caused event B.

  • Hasty Generalization

    • Drawing conclusions based on little evidence or an inadequate sample size.
    • Making broad claims before gathering sufficient representative examples to substantiate the generalization.

  • Oversimplification

    • Assigning insufficient causes to explain an effect or justify a conclusion.
    • Ignores the complexity and multiplicity of factors contributing to an outcome.

Fallacies of Comparison and Definition

  • False Analogy

    • Employing faulty comparisons between two disparate entities or concepts that lack relevant shared qualities.
    • Example: Comparing children to domestic animals, such as asserting "kids are like dogs."

  • Equivocation

    • Shifting the meaning of a word or phrase within the course of an argument to deceive or mislead.
    • Example: Shifting the meaning of professional titles, such as asserting that "Dr. Davis can prescribe medicine" by conflating an academic doctorate (Ph.D.) with a medical doctor (M.D.).

  • Either/Or Reasoning (False Dilemma)

    • Acting as though a complicated argument has only two sides or possibilities when multiple alternatives exist.
    • Forces a complex issue into an artificial binary choice.

Fallacies of Authority and Personal Attack

  • Ad Hominem

    • Latin translation: "to the man."
    • Attacking a person's individual qualities, character, or traits for the sake of argument, rather than engaging with the merits of their actual claim.

  • Guilt by Association

    • Attacking someone by attacking their associates, friends, or network rather than addressing the individual's specific argument or character.

  • Appeal to Doubtful Authority

    • Citing the opinions of someone else as expert testimony when that person lacks genuine expertise or authoritative standing on the topic in question.

  • Begging the Question

    • Taking for granted what is supposed to be proved in the first place.
    • Defending an idea simply by assuming it is true within the premise.

  • Bandwagon

    • Defending an idea by assuming it is true on the basis of widespread acceptance or common belief.