About this topic
Summary Informal Logic is not an alternative to formal logic. It is, broadly, the normative philosophical study of reasoning, inference and argumentation in natural language. Informal logic seeks to provide advice to "real life" arguers in the hopes of enabling them to argue more reasonably, to avoid fallacies, and to achieve greater success in persuasion through cogent, well-reasoned argumentation. Another goal of informal logic is to improve the teaching of reasoning skills.  Some issues that might be considered distinctive to informal logic include: the metaphysical question of whether arguments are abstract objects, events, or something else, what makes arguments in natural languages good or bad, the relationship between argument and justification, theories of virtuous arguing, the nature of fallacies, the problem of deep disagreement between both peer and non-peer arguers, the nature of multi-modal arguments (arguments critically involving non-linguistic elements like images or sounds), and how to achieve more socially just norms and practices of everyday argumentation.
Key works Many of the interests now gathered under the banner of informal logic well predate the emergence of the field as a distinct area of study. Arguably, the tradition begins with Aristotle, the Organon and the Rhetoric both being of central relevance. The first section of Hansen & Pinto 1995 contains entries by writers like Locke, Whately, and Mill, all of whom are important for the history of informal logic. In the 20th century, Hamblin 1970, Toulmin 1958, and Perelman 1969 are considered seminal works in the field. Wellman 1971 is important because it is a point of continuity between the history of attempts in ethics to arrive at standards of good moral reasoning distinct from the canons of formal deductive logic, and informal logic's broader attempt to do the same. A good guide to the early history of informal logic can be found in Johnson 2014. It is also important to note the confluence between early work on critical thinking and informal logic. This is captured in Johnson 2012.
Introductions Walton 2008 and Govier 1991 are accessible textbooks by two of the field's most influential writers. Important technical treatments showcasing the current diversity of approaches within informal logic include the following: Pinto 2003, Tindale 2013, Johnson 2000, Freeman 2004, Walton et al 2008, Hitchcock 2006, Groarke 2015 and Finocchiaro 2013.
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  1. How To Argue (And How Not To).Danny Frederick - manuscript
    I distinguish arguments and arguing and I explain some important logical features of arguments. I then explain how philosophers have been misled, apparently by Euclid, into giving seriously mistaken accounts of arguing. I give a few examples. I then offer a seven-step guide on how to argue. After that, I conclude.
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  2. Any Dispute May Be Resolved By Argument But Rational People May Disagree About Anything.Danny Frederick - manuscript
    Two common claims in philosophy are that deep disagreements cannot, in principle, be resolved by argument and that normal disagreements will be resolved by argument. In each claim it is assumed that the parties to the disagreement are rational. I argue that both claims are false. The first fails to take account of refutations. The second fails to recognise the role of conjectures in the dynamics of the growth of knowledge. There is no disagreement such that it is impossible for (...)
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  3. Looking for the Missing Antecedent.Matheus Silva - manuscript
    The conclusion of a valid deductive argument is contained in its premises, but the deductive argument can still be informative if the arguer is trying to find the missing premises that together with the accepted premises will ensure the truth of the conclusion. Necessarily true conditionals have a deductive-like character so their consequents are contained in their antecedents. These conditionals can be informative, so we need to find the missing antecedent that makes the connection between the antecedent and the consequent. (...)
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  4. Making Sense of Deduction.Matheus Silva - manuscript
    An argument is deductive when the arguer believes the truth of the premises necessitates the truth of the conclusion. A deductive argument is valid when the arguer’s claim is true, i.e., when there are no possible worlds whether the premises are true and the conclusion is false. But in order to evaluate this claim in an accurate manner we need to consider three qualifications that have been repeatedly ignored in the literature, namely, consistency in the attribution of truth values, world (...)
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  5. Restricted and Unrestricted Modus Ponens.Matheus Silva - manuscript
    In a typical modus ponens the reasoner will (a) assert that a premise materially implies a conclusion in a given world; (b) assert this premise and (c) infer the conclusion. But this restricted modus ponens has little in common with the unrestricted textbook modus ponens, since the latter claims that there are no possible worlds where: (a’) a premise materially implies a conclusion, (b’) that premise is true and (c’) the conclusion is false. It is clear that this textbook modus (...)
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  6. The False Promises of Logic Textbooks - How Logic Has a Much More Limited Role Than People Usually Think.Matheus Silva - manuscript
    Logic textbooks advertise that they can teach how to spot a valid argument by its logical form alone. They also boast having collections with the most basic valid argumentative forms people of flesh and blood can use in deductive matters. Think about this for a moment. These are bold statements. If they were accurate, philosophers would be in higher demand than software engineers and no one would be able to make contributions to theoretical physics without ever taking a logic class. (...)
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  7. Is Classical Logic Monotonic?Matheus Silva - manuscript
    It is usually accepted that one of the properties of classical logic is monotonicity, which states that the validity of implication is not affected by the addition of new premises. In this piece, I will argue that this common notion is unjustified since it is motivated by a category mistake. The notion of monotonicity is primarily epistemic in character and can’t be meaningfully attributed to a system. This is acutely clear in the contrast of monotonicity with non-monotonicity, which we tend (...)
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  8. In Defense of Hypothetical Syllogism.Matheus Silva - manuscript
    Moti Mizrahi (2013) presented a putative counterexample to Hypothetical Syllogism (HS) for indicative conditionals aiming to succeed where previous attempts to refute HS have failed. Lee Walters (2014a) objected that Mizrahi’s putative counterexample results from an inadequate analysis of conditionals with embedded modals, but advanced new putative counterexamples to HS for subjunctive conditionals that are supposed to bypass this issue (Walters, 2014a; 2014b). It is argued that Walter’s analysis of embedded modals is unnecessary to prevent Mizrahi’s putative counterexample, since the (...)
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  9. Keep All Your Textbooks.Matheus Silva - manuscript
    Akman (2017) argued that our logic textbooks should be burned, since they present a propositional analysis of necessary and sufficient conditions that leads to a contradiction. According to Akman, we should instead adopt a first-order analysis where conditions are interpreted as one-place predicates. I will argue that (1) Akman’s argument fails to show that the propositional analysis of conditions leads to a contradiction, since the negation of a conjunction is not a conjunction with negated conjuncts, but rather a disjunction with (...)
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  10. No Computer Program Required: Even Pencil-and-Paper Argument Mapping Improves Critical Thinking Skills.Mara Harrell - manuscript
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  11. The Carneades Argumentation Framework: Using Presumptions and Exceptions to Model Critical Questions.Douglas Walton with Chris Reed - manuscript
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  12. Relevance in the Law: A Logical Perspective.Author unknown - manuscript
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  13. Examination Dialogue: An Argumentation Framework for Critically Questioning an Expert Opinion.Douglas Walton - manuscript
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  14. Visualization Tools, Argumentation Schemes and Expert Opinion Evidence in Law.Douglas Walton - manuscript
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  15. Common Knowledge in Argumentation.Douglas Walton & Fabrizio Macagno - manuscript
    Studies in Communication Sciences, 6, 2006, 3-26 . [link to online version posted].
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  16. Begging the Question is Not a Fallacy.John Woods - manuscript
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  17. Chapter XIII. Erotetic Reasoning.Anna Brożek - unknown - Poznan Studies in the Philosophy of the Sciences and the Humanities 99:279-306.
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  18. Critical Thinking: A Guide to Evaluating Information. [REVIEW]Jim Gough - unknown - Eidos: The Canadian Graduate Journal of Philosophy 3.
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  19. Fallacy, What Fallacy? Theaetetus and the Instances of Knowledge.Fraser Landry - unknown - Eidos: The Canadian Graduate Journal of Philosophy 4.
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  20. Courageous Arguments and Deep Disagreements.Andrew Aberdein - forthcoming - Topoi:1-8.
    Deep disagreements are characteristically resistant to rational resolution. This paper explores the contribution a virtue theoretic approach to argumentation can make towards settling the practical matter of what to do when confronted with apparent deep disagreement, with particular attention to the virtue of courage.
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  21. Argumentos contra la persona y conflictos de intereses.Luis Felipe Bartolo Alegre - forthcoming - In Actas de la VI Jornada de Lógica y Argumentación.
    In this paper, I study the relation between arguments against the person (aka ad hominem or personal attack arguments) and disqualifications for conflicts of interests. I show that both types of arguments share a similar logical structure and that they can be considered to be acceptable in similar circumstances.
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  22. Rhetoric of “Stakeholding.”.David M. Berube - forthcoming - Nanoethics: The Ethical and Social Implications of Nanotechnology.
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  23. Alban BOUVIER, L'argumentation Philosophique. Etude de Sociologie Cognitive.M. Bourdeau - forthcoming - Revue Internationale de Philosophie.
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  24. Argumentation: A New Paradigm?M. M. Carrilho - forthcoming - Revue Internationale de Philosophie.
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  25. El Sector Informal.Jacques Charmes - forthcoming - Humanitas.
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  26. Descartes Et l'Argumentation Philosophique, Sous la Direction de Frederic Cossutta.E. Danblon - forthcoming - Revue Internationale de Philosophie.
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  27. Using Questions to Think: How to Develop Skills in Critical Understanding and Reasoning.Nathan Eric Dickman - forthcoming - Bloomsbury Academic.
    Our ability to think, argue and reason is determined by our ability to question. Questions are a vital component of critical thinking, yet we underestimate the role they play. Using Questions to Think puts questioning back in the spotlight. Naming the parts of questions at the same time as we name parts of thought, this one-of-a-kind introduction allows us to see how questions relate to the definitions of propositions, premises, conclusions, and the validity of arguments. Why is this important? Making (...)
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  28. Thinking & Reasoning.Michael E. Doherty - forthcoming - Thinking and Reasoning: Soucial Judgement Theory.
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  29. On Systems of Rhetoric+ Reprinted From'philosophy and Rhetoric'vol 1, Issue 3, Pg 131-44, 1968.D. Ehninger - forthcoming - Philosophy and Rhetoric.
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  30. Feminist Philosophy and the Genetic Fallacy.Nancy Fraser - forthcoming - Hypatia.
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  31. The Toulmin Brief.Emily Friedrich - forthcoming - Argumentation.
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  32. Toward a Feminist Poetic of Critical Thinking.James W. Garrison & A. Phelan - forthcoming - Philosophy of Education.
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  33. Forthcoming, Inquiry, Summer 2004.Darren Grant & Melayne Morgan McInnes - forthcoming - Inquiry: An Interdisciplinary Journal of Philosophy.
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  34. Diálogos Na Dissertação Escolar: Um Estudo Sobre Os Enunciados de Senso Comum E de Polêmica/Dialogues at the Scholarly Argumentative Text: An Analysis of Consensual and Polemical Enunciates.Rinaldo Guariglia - forthcoming - Bakhtiniana.
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  35. Meta-Argumentation Modelling I: Methodology and Techniques.Dov Guido Boella, Leendert der Torre M. Gabbavany & Serena Villata - forthcoming - Studia Logica.
    In this paper, we introduce the methodology and techniques of meta-argumentation to model argumentation. The methodology of meta-argumentation instantiates Dung’s abstract argumentation theory with an extended argumentation theory, and is thus based on a combination of the methodology of instantiating abstract arguments, and the methodology of extending Dung’s basic argumentation frameworks with other relations among abstract arguments. The technique of meta-argumentation applies Dung’s theory of abstract argumentation to itself, by instantiating Dung’s abstract arguments with meta-arguments using a technique called flattening. (...)
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  36. Editorial: A Dialogue on Logic.Sven Ove Hansson - forthcoming - Theoria.
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  37. Feminist Perspectives on Argumentation.Catherine E. Hundleby - forthcoming - Stanford Encyclopedia of Philosophy.
    Feminists note an association of arguing with aggression and masculinity and question the necessity of this connection. Arguing also seems to some to identify a central method of philosophical reasoning, and gendered assumptions and standards would pose problems for the discipline. Can feminine modes of reasoning provide an alternative or supplement? Can overarching epistemological standards account for the benefits of different approaches to arguing? These are some of the prospects for argumentation inside and outside of philosophy that feminists consider. -/- (...)
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  38. The Recent Development of Informal Logic.Ralph H. Johnson & J. Anthony Blair - forthcoming - Informal Logic: The First International Symposium.
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  39. The Nature and Classification of Fallacies.Howard Kahane - forthcoming - Informal Logic: The First International Symposium. Ca: Edgepress.
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  40. Case-Based Reasoning and the Deep Structure Approach to Knowledge Representation, in Proceedings of the Third International Conference On.Andrej Kowalski - forthcoming - Artificial Intelligence and Law.
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  41. Reflections on the Genetic Fallacy.Thelma Z. Lavine - forthcoming - Social Research.
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  42. Persuasion by Our Art is Always Linked with Our Science—in the Exhaustiveness of Our Research.Yvonna S. Lincoln - forthcoming - Mind.
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  43. Essentials of Dialogism: Aspects and Elements of a Dialogical Approach to Language.Per Linell - forthcoming - Communication and Cognition: An Interdisciplinary Quarterly Journal.
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  44. Why Be Critical?(Or Rational or Moral?) On the Justification of Critical Thinking.Christine McCarthy - forthcoming - Philosophy of Education.
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  45. Critical Thinking Without Logic: Restoring Dignity to Information.John McPeck - forthcoming - Philosophy of Education.
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  46. Persuasion and the Dependence Effect.Reese Miller - forthcoming - Business Ethics in Canada.
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  47. Interface Rhetoric.Andrew Morrison & Even Westvang - forthcoming - Kairos.
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  48. Testing for Critical Thinking.H. Petrie - forthcoming - Philosophy of Education.
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  49. Formal and Informal Decision-Making at EU Level.Florin Popa - forthcoming - Cogito.
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  50. Some Antistrophes to The'rhetoric'+ Reprinted From'philosophy and Rhetoric'vol 1, Issue 3, Pg 145-64, 1968.R. Price - forthcoming - Philosophy and Rhetoric.
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1 — 50 / 5172