Informal fallacy

Lore & Background

Informal fallacies are distinguished from formal fallacies, which are errors solely in an argument's form. The source of error in informal fallacies lies in the content and context of the argument, often involving ambiguous or vague expressions, or implicit premises. Traditionally, many informal fallacies have been identified, including equivocation, amphiboly, composition and division, false dilemma, begging the question, ad hominem, and appeal to ignorance. There is no general agreement on how to categorize them, though one approach distinguishes fallacies of ambiguity, presumption, and relevance. Contemporary philosophy has introduced additional frameworks. The dialogical approach views arguments as moves in a dialogue-game aimed at rational persuasion, where fallacies are violations of dialogue rules. The epistemic approach sees arguments as aiming to expand knowledge, with fallacies breaking rules of epistemic justification. A specific form of this is the Bayesian approach, which uses probability laws as epistemic norms. Some arguments traditionally seen as informal fallacies may not be considered fallacious from these perspectives, or at least not in all cases. The study of fallacies aims to provide an account for evaluating and criticizing arguments, involving both descriptive and normative aspects. In philosophy, fallacies are usually seen as bad arguments. In non-scholarly discourse, fallacies are sometimes conceived not as arguments but as false yet popular beliefs.

Reader's Guide

The concept of informal fallacy is central to informal logic and the evaluation of everyday reasoning. Unlike formal fallacies, which are purely structural errors, informal fallacies require analysis of content and context, making them more relevant to real-world arguments in politics, advertising, and debate. The traditional definition of a fallacy as an argument that is invalid and appears valid has been modified for informal fallacies to include broader logical weakness. The psychological element of appearing correct is controversial, as it complicates normative assessment. Contemporary approaches like the dialogical and epistemic frameworks offer alternative ways to identify fallacies, sometimes reclassifying traditional examples. The Bayesian approach applies probability theory to epistemic norms. These developments show that the study of informal fallacies is not settled; it involves ongoing debate about what constitutes a fallacy and how to categorize them. The field remains important for critical thinking, as it provides tools to detect and avoid misleading arguments in natural language.

Did You Know?

• Informal fallacies are a type of incorrect argument in natural language, with the source of error due to content and context rather than form.
• Traditionally identified informal fallacies include equivocation, amphiboly, composition and division, false dilemma, begging the question, ad hominem, and appeal to ignorance.
• There is no general agreement on how to group informal fallacies into categories; one approach distinguishes fallacies of ambiguity, presumption, and relevance.
• Some contemporary frameworks, such as the dialogical and epistemic approaches, may not consider some traditional informal fallacies as fallacious in all cases.