Presuppositions are at the same time a crucial and almost neglected dimension of arguments and fallacies. Arguments involve different types of presuppositions, which can be used for manipulative purposes in distinct ways. However, what are presuppositions? What is their dialectical function? Why and how can they be dangerous? This paper intends to address these questions by developing the pragmatic approaches to presupposition from a dialectical perspective. The use of presuppositions will be analyzed in terms of presumptive conclusions concerning the interlocutor’s (...) acceptance of a proposition, which can be assessed as reasonable or unacceptable. Their dialectical function is described in terms of dark side commitments attributed to a collective "voice" representing what is commonly shared. For this reason, they count as attempts to include the presupposed contents into the hearer’s commitment store, which in some circumstances can reverse the burden of proof. The different manipulative strategies grounded on controversial presuppositions will be examined by showing the distinct roles that the latter play and the relationship between the degrees of presuppositional implicitness and the speaker’s burden of retraction. (shrink)

Within the Gricean framework in pragmatics, communication is understood as an inferential activity. Other approaches to the study of linguistic communication have contended that language is argumentative in some essential sense. My aim is to study the question of whether and how the practices of inferring and arguing can be taken to contribute to meaning in linguistic communication. I shall suggest a two-fold hypothesis. First, what makes of communication an inferential activity is given with its calculability, i.e. with the possibility (...) to rationally recover the assigned meaning by means of an explicit inference. Secondly, the normative positions that we recognize and assign each other with our speech acts comprise obligations and rights of a dialectical character; but this fact does not entail nor presuppose an argumentative nature in language or speech. Both inferring and arguing are needed, however, in the activity of justifying and assessing our speech acts. (shrink)

Traditionally, a presumption is a dialogically privileged, yet defeasible proposition that allocates the burden of proof to a party who challenges it. This paper investigates the strength of presumptions. First, it explains how ‘strength’ contributes to defining the concept of presumption. Second, it provides an overview of (contextual, justificatory, and deontic) factors determining a presumption’s strength. Finally, it analyses the predominant view that defines strength in terms of the Challenger’s burden of proof: the stronger (weaker) the presumptionp, the more (less) (...) difficult it is to prove non-p. I argue that the latter proposal applies only to practical presumptions, and that strength is conceived differently for cognitive presumptions. (shrink)