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    Non-monotonicity and informal reasoning: comment on Ferguson (2003)

    Oaksford, Mike and Hahn, Ulrike (2006) Non-monotonicity and informal reasoning: comment on Ferguson (2003). Argumentation 20 (2), pp. 245-251. ISSN 0920-427X.

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    In this paper, it is argued that Ferguson’s (2003, Argumentation 17, 335–346) recent proposal to reconcile monotonic logic with defeasibility has three counterintuitive consequences. First, the conclusions that can be derived from his new rule of inference are vacuous, a point that as already made against default logics when there are conflicting defaults. Second, his proposal requires a procedural “hack” to the break the symmetry between the disjuncts of the tautological conclusions to which his proposal leads. Third, Ferguson’s proposal amounts to arguing that all everyday inferences are sound by definition. It is concluded that the informal logic response to defeasibility, that an account of the context in which inferences are sound or unsound is required, still stands. It is also observed that another possible response is given by Bayesian probability theory (Oaksford and Chater, in press, Bayesian Rationality: The Probabilistic Approach to Human Reasoning, Oxford University Press, Oxford, UK; Hahn and Oaksford, in press, Synthese).


    Item Type: Article
    Keyword(s) / Subject(s): Bayesian reasoning, defeasibility, informal logic, logic, non-mononoticity
    School: Birkbeck Faculties and Schools > Faculty of Science > School of Psychological Sciences
    Research Centres and Institutes: Birkbeck Knowledge Lab
    Depositing User: Administrator
    Date Deposited: 20 Sep 2016 14:21
    Last Modified: 02 Aug 2023 17:26


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