8: Detecting Fallacies
- Page ID
- 22005
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)In earlier chapters we examined several techniques of deception: exaggeration, telling only half the truth, and using loaded language. Fallacies are errors in reasoning, and they can be used to deceive, as we saw in the discussion of the fallacy of avoiding the issue, the red herring, and misplacing the burden of proof. In this chapter, we explore other important fallacies. Knowing the main ways that people are lured into these errors will improve your chances for logical self-defense in the future.
- 8.1: Ad Hominem Fallacy
- This page explains the ad hominem fallacy, emphasizing that it involves discrediting the individual instead of addressing the argument. It clarifies that, while many ad hominem attacks are flawed, some can be valid if the person's traits are relevant. The page includes examples to illustrate how to identify such attacks and discusses the importance of focusing on the argument rather than personal characteristics.
- 8.2: Fallacy of Circular Reasoning
- This page covers circular reasoning and the Bialystok fallacy, highlighting how reasoning can loop back on itself through circular justification or definitions. It defines circular reasoning, also known as "begging the question," and provides an example where the statement that smoking is harmful is justified by the claim that smoking harms health, illustrating the deficiency in proper justification.
- 8.3: Straw Man Fallacy
- This page explains the straw man fallacy, highlighting how it misrepresents an opponent's argument to attack a weaker version instead of addressing the real position. It stresses the importance of fair representation of viewpoints, using examples to show how misinterpretations detract from meaningful debate. The page also recommends that effective responses clarify intentions and promote accurate discussions of the original points made.
- 8.4: False Dilemma Fallacy
- This page explores the false dilemma fallacy, where limited choices mislead audiences, illustrated by examples like a questionnaire on alcohol use. It highlights the black-white fallacy, which confines options to two extremes, and contrasts this with true dilemmas that may involve serious consequences. Political examples show how slanting choices influences opinions. The text underscores the necessity of recognizing and challenging false dilemmas to reveal overlooked alternatives.
- 8.5: Fallacy of Faulty Comparison
- This page explains the fallacy of faulty comparison in advertising, highlighting misleading examples from gardening gloves, mouthwash, and motor oil. It critiques ads that suggest comparisons to irrelevant options or single competitors, like the Jones & Jones gloves comparing to bare hands and Flox mouthwash omitting other brands. Enzine motor oil is also discussed for similar reasons. Overall, the page emphasizes how advertisements often present half-truths by selectively choosing comparisons.
- 8.6: Fallacious Appeal to Authority
- This page explores the concept of knowledge, defining it as justified true belief. It emphasizes that beliefs based on authority without proper justification do not constitute knowledge. The text uses historical examples, like the medieval flat Earth belief, to demonstrate that even reasonable justifications can lead to false beliefs. Ultimately, it asserts that true knowledge requires both a true belief and sufficient justification, distinguishing it from mere opinion.
- 8.7: Slippery Slope Fallacy
- This page discusses the slippery slope fallacy, which occurs when an argument claims a minor action will lead to significant negative consequences without proper evidence. It uses smoking as an example, illustrating the flawed logic in sequential reasoning where low probabilities render the conclusion invalid. A thorough analysis is necessary to evaluate the likelihood of each step in the proposed chain of events.
- 8.8: Genetic Fallacy
- This page explains the genetic fallacy, where a claim is invalidated based on its source instead of its merit. It provides examples, including the rejection of Senator Friedman's redistricting idea due to its origin from a dream and Freud's critique of faith tied to psychological needs. Additionally, it discusses a president's faulty reasoning in ignoring a senator's argument about crisis responsibility by concentrating on the political motivations instead of the core issue.
- 8.9: Non Sequitur
- This page explores non sequitur arguments, highlighting that their conclusions do not logically follow from their premises. It distinguishes weak arguments, which offer some reasoning, from non-arguments, which provide no support. The text includes examples to clarify these concepts and encourages readers to recognize weak reasoning in arguments and respond skeptically.
- 8.10: Review of Major Points
- This page explores the qualities of effective logical reasoning, highlighting the need to concentrate on relevant topics and represent opposing views accurately. It identifies fallacies such as ad hominem and straw man that result from lapses in these areas, noting their persuasive yet unethical nature. The page emphasizes that an argument’s validity isn’t solely based on its logical form but on its relevance.
- 8.11: Glossary
- This page explores various logical fallacies that hinder sound reasoning, defining terms such as ad hominem, false dilemma, and straw man. It highlights how these fallacies divert attention from the main argument and create misleading choices. The text further discusses fallacious appeals to authority, faulty comparisons, and non sequiturs, while emphasizing that effective refutation should involve genuine disproof rather than mere contradiction.
- 8.12: Exercises
- This page explores various logical fallacies, including ad hominem attacks, false dilemmas, straw man fallacies, and others, with examples and exercises for identification and correction. It emphasizes critical thinking and sound reasoning in discussions on diverse topics, urging readers to create their own examples and engage in exercises to deepen understanding. The content aims to enhance reasoning skills by illustrating the impact of fallacies on argument clarity and validity.