In this paper, I distinguish between linguistic and non-linguistic presuppositions. I also propose that we should be interested in conversational presuppositions, which could also be called speaker-meant presuppositions or speaker's presuppositions. I also distinguish between potential and actual presuppositions. I propose that, in some cases, presuppositions can be conversationally implicated and cancellation is possible. I specify what the hard cases are and I try to explain them through ontological considerations. I try to reduce the hard cases through (a) the notion (...) that all actual presuppositions are speaker-meant; (b) the distinction between ontological and linguistic presuppositions; and (c) the uncontroversial notion that even ontological presuppositions are susceptible to semantic under-determination that has to be tackled though pragmatic intrusion. Pragmatic intrusion for presuppositional cases, however, cannot really amount to completing or expanding or in any case computing an explicature in an ordinary sense, as explicatures have to do with truth-conditions and aim to create propositionally complete forms that are truth-evaluable, unlike propositional fragments or schemata that are usually expressed in sentences (; , 2012). They are processes similar to explicatures, but since presuppositions are only pre-conditions for an utterance's being true or false (; Macagno; 2016; ; ), we cannot say that these processes are completely like those of explicatures. Nevertheless, they are pragmatically-motivated, even if hard to cancel. (See on lack of cancellability or on entrenched meanings.) This more or less brings my approach in line with contextualism (even if I accept semantic invariantism, along the lines of or (Invariantism is also shared by , in a form that is compatible with her contextualism.)). (shrink)

Abstract: The article presents and critically discusses Walton's (and Reed's and Macagno's) argument scheme approach to a theory of good argumentation. In particular, four characteristics of Walton's approach are presented: 1. It presents normative requirements for argumentation in the form of argument schemes, i.e. relatively concrete type descriptions. 2. These schemata are enthymematic, i.e. they omit some of the premises required by other approaches. 3. The actual argument schemes are usually supplemented by critical questions. 4. The method is inductive, (...) bottom-up, gaining the normative schemata by abstraction from empirically collected groups of similar arguments. These characteristics, among others, are then discussed on the basis of four adequacy conditions: AC1: effectiveness in achieving the epistemic goal of obtaining and communicating justified acceptable opinions; AC2: completeness in capturing the good argument types; AC3: efficiency in achieving the goals; AC4: justification of the argument schemes. The discussion then reveals a number of weaknesses in Walton's argument schemes; among other things, they are neither effective (in the defined sense) nor truly justified. Contributing factors to these problems include the schema approach, i.e. not looking at the form of arguments, and the lack of epistemological foundations in the development of good types of arguments. However, the critical analyses reveal a better alternative: an epistemological approach based on epistemological principles. The article concludes with a detailed analysis of the scheme Practical Inference, which confirms the general criticism in detail. (shrink)