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. Dialectics: A Controversy-Oriented Approach to the Theory of Knowledge. [REVIEW] A. - 1978 - Review of Metaphysics 32 (2):368-368.
  2. Good Reasoning Matters: A Constructive Approach to Critical Thinking.Leo A. Groarke & Christopher W. Tindale - 2012 - Oxford University Press Canada.
    Now in its fifth edition, Good Reasoning Matters! is a practical guide to recognizing, evaluating, and constructing arguments. Combining straightforward instruction with abundant exercises and examples, this innovative introduction to argument schemes and rhetorical techniques will help students learn to think critically both within and beyond the classroom.
  3. Elements of Formal Logic. [REVIEW]E. J. A. - 1965 - Review of Metaphysics 19 (2):379-379.
  4. The Art of Critical Thinking. [REVIEW]E. J. A. - 1965 - Review of Metaphysics 19 (2):381-381.
  5. Logic: A Dialogue. [REVIEW]J. A. - 1965 - Review of Metaphysics 18 (3):581-582.
  6. Dialectics.S. C. A. - 1978 - Review of Metaphysics 32 (2):368-368.
  7. Argumentation in Large, Complex Practices.Aakhus Mark, Ziek Paul & Dadlani Punit - unknown
    Differences arise in macro-activities, such as the production of energy, food, and healthcare, where the management of these differences happens in polylogues as many actors pursue scores of positions on a variety of issues in numerous venues. Polylogues are essential to the large-scale practices that organize macro-activities but present significant challenges for argumentation theory and research. Key to the challenge is conceptualizing the variety of argumentative roles that go beyond the classic normative definition of protagonist and antagonist. A macroscope is (...)
  8. Commentary on “Objectivity in Newsmaking: An Argumentative Perspective”: Reflections on Argument in Practice.Mark Aakhus - unknown
  9. Frans H. Van Eemeren and Bart Garssen : Topical Themes in Argumentation Theory: Twenty Exploratory Studies.Mark Aakhus - 2014 - Argumentation 28 (4):489-492.
    Every 4 years, for the past three decades, the world of argumentation research has gathered in Amsterdam at the International Society for the Study of Argumentation conferences to explore advances in understanding argumentation and how argumentation advances our understanding of the human condition. While comprehensive proceedings of selected papers are produced to document what has transpired in the world of argumentation over the preceding 4 years, there remains the important matter of taking the intellectual pulse of the world’s argumentation scholars, (...)
  10. Neither Naïve nor Critical Reconstruction: Dispute Mediators, Impasse, and the Design of Argumentation.Mark Aakhus - 2003 - Argumentation 17 (3):265-290.
    This study investigates how dispute-mediators handle impasse in the re-negotiation of divorce decrees by divorced couples. Three sources of impasse and three strategies for handling impasse are identified based on analysis of mediation transcripts. The concern here lies not so much in the disputant's arguments but in the discussion procedures dispute-mediators use to craft the disputant's argumentation into a tool to solve conflict. Their moves are understood here as a practice of reconstructing argumentative discourse that is neither naïve nor critical (...)
  11. Advancing Polylogical Analysis of Large-Scale Argumentation: Disagreement Management in the Fracking Controversy.Mark Aakhus & Marcin Lewiński - 2017 - Argumentation 31 (1):179-207.
    This paper offers a new way to make sense of disagreement expansion from a polylogical perspective by incorporating various places in addition to players and positions into the analysis. The concepts build on prior implicit ideas about disagreement space by suggesting how to more fully account for argumentative context, and its construction, in large-scale complex controversies. As a basis for our polylogical analysis, we use a New York Times news story reporting on an oil train explosion—a significant point in the (...)
  12. Integrating Natural Language Processing and Pragmatic Argumentation Theories for Argumentation Support.Mark Aaknus, Smaranda Muresan & Nina Wacholder - unknown
    Natural language processing research and design that aims to model and detect opposition in text for the purpose of opinion classification, sentiment analysis, and meeting tracking, generally excludes the interactional, pragmatic aspects of online text. We propose that a promising direction for NLP is to incorporate the insights of pragmatic, dialectical theories of argumentation to more fully exploit the potential of NLP to offer sound, robust systems for various kinds of argumentation support.
  13. The Reasonable as Rational? On Legal Argumentation and Justification : Festschrift for Aulis Aarnio.Aulis Aarnio & Werner Krawietz - 2000
  14. Methodologie Und Erkenntnistheorie der Juristischen Argumentation Beiträge des Internationalen Symposions "Argumentation in Legal Science" Vom 10. Bis 12. Dezember 1979 in Helsinki. [REVIEW]Aulis Aarnio, Ilkka Niiniluoto & Jyrki Uusitalo - 1981
  15. Fallaciousness and Invalidity.Charles J. Abaté - 1979 - Philosophy and Rhetoric 12 (4):262 - 266.
  16. Taylor's Fatal Fallacy.Raziel Abelson - 1963 - Philosophical Review 72 (1):93-96.
  17. Virtuous Norms for Visual Arguers.Andrew Aberdein - 2018 - Argumentation 32 (1):1-23.
    This paper proposes that virtue theories of argumentation and theories of visual argumentation can be of mutual assistance. An argument that adoption of a virtue approach provides a basis for rejecting the normative independence of visual argumentation is presented and its premisses analysed. This entails an independently valuable clarification of the contrasting normative presuppositions of the various virtue theories of argumentation. A range of different kinds of visual argument are examined, and it is argued that they may all be successfully (...)
  18. Arguments with Losers.Andrew Aberdein - 2016 - Florida Philosophical Review 16 (1):1-11.
  19. Commentary on Patrick Bondy, “Bias in Legitimate Ad Hominem Arguments”.Andrew Aberdein - unknown
  20. The Vices of Argument.Andrew Aberdein - 2016 - Topoi 35 (2):413-422.
    What should a virtue theory of argumentation say about fallacious reasoning? If good arguments are virtuous, then fallacies are vicious. Yet fallacies cannot just be identified with vices, since vices are dispositional properties of agents whereas fallacies are types of argument. Rather, if the normativity of good argumentation is explicable in terms of virtues, we should expect the wrongness of bad argumentation to be explicable in terms of vices. This approach is defended through analysis of several fallacies, with particular emphasis (...)
  21. In Defence of Virtue: The Legitimacy of Agent-Based Argument Appraisal.Andrew Aberdein - 2014 - Informal Logic 34 (1):77-93.
    Several authors have recently begun to apply virtue theory to argumentation. Critics of this programme have suggested that no such theory can avoid committing an ad hominem fallacy. This criticism is shown to trade unsuccessfully on an ambiguity in the definition of ad hominem. The ambiguity is resolved and a virtue-theoretic account of ad hominem reasoning is defended.
  22. Fallacy and Argumentational Vice.Andrew Aberdein - 2013 - In Dima Mohammed & Marcin Lewinski (eds.), Virtues of argumentation: Proceedings of the 10th International Conference of the Ontario Society for the Study of Argumentation (OSSA), May 22–25, 2013. OSSA.
    If good argument is virtuous, then fallacies are vicious. Yet fallacies cannot just be identified with vices, since vices are dispositional properties of agents whereas fallacies are types of argument. Rather, if the normativity of good argumentation is explicable in terms of virtues, we should expect the wrongness of fallacies to be explicable in terms of vices. This approach is defended through case studies of several fallacies, with particular emphasis on the ad hominem.
  23. The Dialectical Tier of Mathematical Proof.Andrew Aberdein - 2011 - In Frank Zenker (ed.), Argumentation: Cognition & Community. Proceedings of the 9th International Conference of the Ontario Society for the Study of Argumentation (OSSA), May 18--21, 2011. OSSA.
    Ralph Johnson argues that mathematical proofs lack a dialectical tier, and thereby do not qualify as arguments. This paper argues that, despite this disavowal, Johnson’s account provides a compelling model of mathematical proof. The illative core of mathematical arguments is held to strict standards of rigour. However, compliance with these standards is itself a matter of argument, and susceptible to challenge. Hence much actual mathematical practice takes place in the dialectical tier.
  24. Virtue in Argument.Andrew Aberdein - 2010 - Argumentation 24 (2):165-179.
    Virtue theories have become influential in ethics and epistemology. This paper argues for a similar approach to argumentation. Several potential obstacles to virtue theories in general, and to this new application in particular, are considered and rejected. A first attempt is made at a survey of argumentational virtues, and finally it is argued that the dialectical nature of argumentation makes it particularly suited for virtue theoretic analysis.
  25. Rationale of the Mathematical Joke.Andrew Aberdein - 2010 - In Alison Pease, Markus Guhe & Alan Smaill (eds.), Proceedings of AISB 2010 Symposium on Mathematical Practice and Cognition. AISB. pp. 1-6.
    A widely circulated list of spurious proof types may help to clarify our understanding of informal mathematical reasoning. An account in terms of argumentation schemes is proposed.
  26. Argumentation Schemes and Communities of Argumentational Practice.Andrew Aberdein - 2009 - In Juho Ritola (ed.), Argument Cultures: Proceedings of OSSA 2009. OSSA.
    Is it possible to distinguish communities of arguers by tracking the argumentation schemes they employ? There are many ways of relating schemes to communities, but not all are productive. Attention must be paid not only to the admissibility of schemes within a community of argumentational practice, but also to their comparative frequency. Two examples are discussed: informal mathematics, a convenient source of well-documented argumentational practice, and anthropological evidence of nonstandard reasoning.
  27. Commentary on Menashe Schwed, "A Wittgensteinian Approach to Rationality in Argumentation".Andrew Aberdein - 2009 - In Juho Ritola (ed.), Argument cultures: Proceedings of OSSA 2009. OSSA.
  28. Fallacies in Mathematics.Andrew Aberdein - 2007 - Proceedings of the British Society for Research Into Learning Mathematics 27 (3):1-6.
    This paper considers the application to mathematical fallacies of techniques drawn from informal logic, specifically the use of ”argument schemes’. One such scheme, for Appeal to Expert Opinion, is considered in some detail.
  29. The Informal Logic of Mathematical Proof.Andrew Aberdein - 2006 - In Reuben Hersh (ed.), 18 Unconventional Essays About the Nature of Mathematics. Springer Verlag. pp. 56-70.
    Informal logic is a method of argument analysis which is complementary to that of formal logic, providing for the pragmatic treatment of features of argumentation which cannot be reduced to logical form. The central claim of this paper is that a more nuanced understanding of mathematical proof and discovery may be achieved by paying attention to the aspects of mathematical argumentation which can be captured by informal, rather than formal, logic. Two accounts of argumentation are considered: the pioneering work of (...)
  30. Managing Informal Mathematical Knowledge: Techniques From Informal Logic.Andrew Aberdein - 2006 - Lecture Notes in Artificial Intelligence 4108:208--221.
    Much work in MKM depends on the application of formal logic to mathematics. However, much mathematical knowledge is informal. Luckily, formal logic only represents one tradition in logic, specifically the modeling of inference in terms of logical form. Many inferences cannot be captured in this manner. The study of such inferences is still within the domain of logic, and is sometimes called informal logic. This paper explores some of the benefits informal logic may have for the management of informal mathematical (...)
  31. Proofs and Rebuttals: Applying Stephen Toulmin's Layout of Arguments to Mathematical Proof.Andrew Aberdein - 2006 - In Marta Bílková & Ondřej Tomala (eds.), The Logica Yearbook 2005. Filosofia. pp. 11-23.
    This paper explores some of the benefits informal logic may have for the analysis of mathematical inference. It shows how Stephen Toulmin’s pioneering treatment of defeasible argumentation may be extended to cover the more complex structure of mathematical proof. Several common proof techniques are represented, including induction, proof by cases, and proof by contradiction. Affinities between the resulting system and Imre Lakatos’s discussion of mathematical proof are then explored.
  32. Raising the Tone: Definition, Bullshit, and the Definition of Bullshit.Andrew Aberdein - 2006 - In G. Reisch & G. Hardcastle (eds.), Bullshit and Philosophy. Open Court. pp. 151-169.
  33. The Uses of Argument in Mathematics.Andrew Aberdein - 2005 - Argumentation 19 (3):287-301.
    Stephen Toulmin once observed that ”it has never been customary for philosophers to pay much attention to the rhetoric of mathematical debate’ [Toulmin et al., 1979, An Introduction to Reasoning, Macmillan, London, p. 89]. Might the application of Toulmin’s layout of arguments to mathematics remedy this oversight? Toulmin’s critics fault the layout as requiring so much abstraction as to permit incompatible reconstructions. Mathematical proofs may indeed be represented by fundamentally distinct layouts. However, cases of genuine conflict characteristically reflect an underlying (...)
  34. Douglas Walton, One-Sided Arguments: A Dialectical Analysis of Bias. [REVIEW]Andrew Aberdein - 2001 - Philosophy in Review 21 (2):152-154.
  35. Persuasive Definition.Andrew Aberdein - 1997 - In H. V. Hansen, C. W. Tindale & A. V. Colman (eds.), Argumentation and Rhetoric. Vale.
    Charles Stevenson introduced the term 'persuasive definition’ to describe a suspect form of moral argument 'which gives a new conceptual meaning to a familiar word without substantially changing its emotive meaning’. However, as Stevenson acknowledges, such a move can be employed legitimately. If persuasive definition is to be a useful notion, we shall need a criterion for identifying specifically illegitimate usage. I criticize a recent proposed criterion from Keith Burgess-Jackson and offer an alternative.
  36. Introduction: Virtues and Arguments.Andrew Aberdein & Daniel H. Cohen - 2016 - Topoi 35 (2):339-343.
    It has been a decade since the phrase virtue argumentation was introduced, and while it would be an exaggeration to say that it burst onto the scene, it would be just as much of an understatement to say that it has gone unnoticed. Trying to strike the virtuous mean between the extremes of hyperbole and litotes, then, we can fairly characterize it as a way of thinking about arguments and argumentation that has steadily attracted more and more attention from argumentation (...)
  37. The Argument of Mathematics.Andrew Aberdein & Ian J. Dove (eds.) - 2013 - Springer.
    Written by experts in the field, this volume presents a comprehensive investigation into the relationship between argumentation theory and the philosophy of mathematical practice. Argumentation theory studies reasoning and argument, and especially those aspects not addressed, or not addressed well, by formal deduction. The philosophy of mathematical practice diverges from mainstream philosophy of mathematics in the emphasis it places on what the majority of working mathematicians actually do, rather than on mathematical foundations. -/- The book begins by first challenging the (...)
  38. Machine Verification of Mathematical Proof.Paul W. Abrahams - 1972 - Journal of Symbolic Logic 37 (2):411-412.
  39. Fifth International Conference on Philosophy in Practice.Gerd Achenbach, Eulalia Bosch, Eite Veening, Emmy Van Deurzen, Richard Smith, Ida Jongsma, Joanna Haynes, Dorine Baudin & Karin Murris - 1999 - History and Philosophy of Logic 20:77.
  40. Foresight and Understanding. Stephen Toulmin.Peter Achinstein - 1963 - Isis 54 (3):408-410.
  41. The Fallacy of Conjunctive Analysis.Robert Ackermann - 1969 - The Monist 53 (3):478-487.
  42. Discussion.Russell L. Ackoff - 1948 - Philosophy of Science 15 (2):116-117.
  43. Knowing When Disagreements Are Deep.David M. Adams - 2005 - Informal Logic 25 (1):65-77.
    Reasoned disagreement is a pervasive feature of public life, and the persistence of disagreement is sometimes troublesome, reflecting the need to make difficult decisions. Fogelin suggests that parties to a deep disagreement should abandon reason and switch to non-rational persuasion. But how are the parties to know when to make such a switch? I argue that Fogelin's analysis doesn't clearly address this question, and that disputes arising in areas like medical decision making are such that the parties to them have (...)
  44. Special Issue on Priestley Duality.M. Adams & W. Dziobiak - 1996 - Studia Logica 56:1-2.
  45. The Rhetorical Syllogism (Enthymeme) in Judicial Argumentation.João Maurício Adeodato - 1999 - International Journal for the Semiotics of Law - Revue Internationale de Sémiotique Juridique 12 (2):133-150.
    The thesis here expounded can be divided in three parts: in the first place, it is supposed that the syllogism is not the rhetorical way, and less still the logical way, indeed used to reach the decision in the legal proceedings monopolized by the modern State. At the most, it can be seen as a form of presenting a decision that has already been reached by other means. It sure constitutes a highly functional procedure, effective and legitimating. It is generally (...)
  46. Asymmetrical Analogical Arguments.J. E. Adler - 2007 - Argumentation 21 (1):83-92.
    Analogies must be symmetric. If a is like b, then b is like a. So if a has property R, and if R is within the scope of the analogy, then b (probably) has R. However, analogical arguments generally single out, or depend upon, only one of a or b to serve as the basis for the inference. In this respect, analogical arguments are directed by an asymmetry. I defend the importance of this neglected – even when explicitly mentioned – (...)
  47. Are Conductive Arguments Possible?Jonathan Adler - 2013 - Argumentation 27 (3):245-257.
    Conductive Arguments are held to be defeasible, non-conclusive, and neither inductive nor deductive (Blair and Johnson in Conductive argument: An overlooked type of defeasible reasoning. College, London, 2011). Of the different kinds of Conductive Arguments, I am concerned only with those for which it is claimed that countervailing considerations detract from the support for the conclusion, complimentary to the positive reasons increasing that support. Here’s an example from Wellman (Challenge and response: justification in ethics. Southern Illinois University Press, Chicago, 1971): (...)
  48. Argumentation and Distortion.Jonathan Adler - 2007 - Episteme: A Journal of Social Epistemology 4 (3):382-401.
  49. Teaching and the Structural Approach to Fallacies.Jonathan Adler - 1996 - Inquiry: Critical Thinking Across the Disciplines 15 (4):94-106.
  50. Teaching and the Structural Approach to Fallacies.Jonathan Adler - 1996 - Inquiry: Critical Thinking Across the Disciplines 15 (4):94-106.
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