Lilian Bermejo-Luque has posed these questions:1.What is the relationship between presumption and presumptive inference? 2.What are the correctness conditions for presumptions and presumptive inferences? Cohen’s method of relevant variables, Toulmin’s model, and Rescher’s theory of plausibility suggest answers. An inference is presumptive just in case its warrant transfers presumption from its premises to its conclusion. A warrant licencing an inference from the claim that an empirical property φ holds to the claim that some other property ψ holds is backed by (...) observation of a constant conjunction of those properties. The stronger the backing, the stronger the warrant. Warrants may be defeated by instances of φ holding in conjunction with some property χ and ψ not holding. The method of relevant variables directs us to organize such defeating properties into relevant variables. We then test the strength of a warrant by seeing how many variables fail to have a value which defeats the warrant. The more variables with no defeater, the stronger the warrant. We may construct a canonical ordering of the relevant variables by ranking them according to the plausibility of their including defeating values. We may evaluate the strength not only of empirically backed warrants, but warrants backed by institutional rules, such as a branch of law, or by a priori intuited connections between properties. An inference rule will be presumptive just in case the plausibility of its warrant being defeated is below some specified level. (shrink)

To describe how metaphors work from an argumentative point of view is the first step of this paper. After describing the metaphorical argumentative mechanism, the second step is to apply this mechanism by analyzing some paradigmatic international metaphors that are used in public speeches. This analysis will enable us to see some common grounds between different cultures and countries, especially regarding economical issues and argumentation theory.

In a 2006 paper I claimed that the virtue arguments or inferences must have is not that they be truth-preserving, but that they be entitlement-preserving. I offered two reasons there why such a conception of argument virtue is needed for a satisfactory treatment of defeasible arguments and inferences. This paper revisits that claim, and assesses the prospects for a more thorough defence than was offered in that paper.