Posts Tagged ‘defeasible reasoning’

7th eColloq on Argumentation
Thursday April 11, 4-6 pm GMT+1  (Amsterdam, Berlin, Rome, Stockholm)
4.00-4.10 Connect, Welcome
4.10-4:35 Bart Verheij (Groningen, The Netherlands):
Defeasible rule-based arguments with a logico-probabilistic foundation
Abstract: A theory of defeasible arguments is proposed that combines logical and probabilistic properties. This logico-probabilistic argumentation theory builds on two foundational theories of nonmonotonic reasoning and uncertainty: the study of nonmonotonic consequence relations (and the associated minimal model semantics) and probability theory. A key result is that, in the theory, qualitatively defined argument validity can be derived from a quantitative interpretation. The theory provides a synthetic perspective of arguments `jumping to conclusions’, rules with exceptions, and probabilities. The approach is compared to Pollock’s computational model of argumentation OSCAR, designed on the basis of his well-developed positions concerning the relations between argumentation, logic and probability. In contrast with Pollock’s OSCAR, the present approach is compatible with the standard probability calculus.
4:35-4:50 Discussion
4:50-5:00 Break
5:00-5:25 Emmanuel J. Genot (Lund University, Sweden):
The Myth of a Confirmation Bias (Arguments for a better argumentative theory of reasoning)
Abstract: Wason, confronted with an apparent instance of the Fallacy of Affirming the Consequent in his empirical Selection Task, hypothesized a “Confirmation Bias” (CB) to be responsible for subjects’ selections [4]. When Bayesian rational analysis of the selection task (RAST, [3]) substituted a richer probabilistic semantics to Wason’s truth-functional semantics, subjects’ selection emerged as being vindicated, and evidence for CB (in fact, any bias) vanished. Relevance Theorists later produced data that Bayesian models could not accommodate [1], yet without exhibiting evidence for biases of any sort. However, Relevance Theory has more recently been superseded by the Argumentative Theory of Reasoning (ATR, [2]), in which CB has returned with a vengeance, backed by an evolutionary narrative that pits “argumentative” and “logical” competences against one another. I will argue that this narrative is a remnant of the same truncated view of logic (and semantics) that informed Wason’s theorizing, but that argumentation-theoretic considerations are necessary to account for the data. To support this view, I will present a generalization of RAST that accounts for both standard and non-standard cases of ST (resp. from [3, 4] and [1]) once argumentative goals are “factored in,” but with an underlying semantics that undermines the very idea of “logical competence”—without which the CB is but a myth.
Girotto, Kemmelmeier, Sperber & van der Henst. “Inept reasoners or pragmatic virtuosos? Relevance and the deontic selection task”, Cognition, 2001, 81, B69-B7
Mercier & Sperber, Why do humans reason? Arguments for an argumentative theory. Behavioral and Brain Sciences, 2011, 34, 57-74.
Oaksford & Chater. A Rational Analysis of the Selection Task as Optimal Data Selection. Psychological Review, 1994, 101, 608-631
Wason, Reasoning About a Rule. Quarterly Journal of Experimental Psychology, 1968, 20, 273-281
5:25-5:40 Discussion
Discussants (preliminary list)
Nir Oren (University of Aberdeen, UK)
David Hitchcock (McMasters, Canada)
Thomas Gordon (Berlin, Germany)
Jean Goodwin (Iowa State, USA)
Iowan Drehe (University of Cluj-Napoca, Romania)
Sune Holm Petersen (Copenhagen University, Denmark)
Steven Patterson (Marygrove College, Detroit, USA)
Sarah Uckelman (Ruprecht-Karls Universität Heidelberg, Germany)
Marcin Lewinski (New University of Lisbon, Portugal)
Thomas Fischer (University of Houston, Texas, USA)
To participate as a discussant (just “sitting in” is in fact fine!), please review the links under “TechThings” at the above website (to test your hardware) and contact the organizer at frank.zenker@fil.lu.se.
Frank Zenker
Department of Philosophy & Cognitive Science
Kungshuset, Lundagård, 222 22 Lund, Sweden

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Theme: 1951 – 2011: 60 years of DEONTIC LOGIC

Special issue of Journal of Logic and Computation, corner on Deontic Logic and Normative Systems

Paper Submission Deadline: *September 1, 2011*


With his seminal paper “deontic logic” published in Mind in 1951, Von Wright launched the area of deontic logic. It is the field of logic that is concerned with obligation, permission, and related concepts.

We invite papers concerned with the logical study of normative reasoning, including formal systems of deontic logic, defeasible normative reasoning, the logic of action, and other related areas of logic, and the formal analysis of normative concepts and normative systems.

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