The Rationality of Informal Argumentation: A Bayesian Approach to Reasoning Fallacies

• Published in: Psychological review 2007-07, Vol.114 (3), p.704-732
• Main Authors: Hahn, Ulrike, Oaksford, Mike
• Format: Article
• Language: English
• Subjects: Arguments; Bayes Theorem; Bayesian analysis; Bayesian method; Bayesian Statistics; Biological and medical sciences; Cognition & reasoning; Cognition. Intelligence; Cognitive Psychology; Critical thinking; Culture; Dissent and Disputes; Experiments; Fundamental and applied biological sciences. Psychology; Human; Humans; Interpersonal Relations; Judgement; Judgment; Logic; Mind; Persuasive Communication; Persuasive Discourse; Probability Learning; Psychological Characteristics; Psychological Studies; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Reason; Reasoning; Reasoning. Problem solving; Semantics; Social relations; Statistical Probability
• ISSN: 0033-295X; 1939-1471
• DOI: 10.1037/0033-295X.114.3.704

Classical informal reasoning "fallacies," for example, begging the question or arguing from ignorance, while ubiquitous in everyday argumentation, have been subject to little systematic investigation in cognitive psychology. In this article it is argued that these "fallacies" provide a rich taxonomy of argument forms that can be differentially strong, dependent on their content. A Bayesian theory of content-dependent argument strength is presented. Possible psychological mechanisms are identified. Experiments are presented investigating whether people's judgments of the strength of 3 fallacies-the argumentum ad ignorantiam , the circular argument or petitio principii , and the slippery slope argument-are affected by the factors a Bayesian account predicts. This research suggests that Bayesian accounts of reasoning can be extended to the more general human activity of argumentation.