In this thesis, I focus on scalar implicatures, presuppositions and their connections. In chapter 2, I propose a scalar implicature-based account of neg-raising inferences, standardly analyzed as a presuppositional phenomenon (Gajewski 2005, 2007). I show that an approach based on scalar implicatures can straightforwardly account for the differences and similarities between neg-raising predicates and presuppositional triggers. In chapters 3 and 4, I extend this account to “soft” presuppositions, a class of presuppositions that are easily suspendable (Abusch 2002, 2010). I show how such account can explain the differences and similarities between this class of presuppositions and other presuppositions on the one hand, and scalar implicatures on the other. Furthermore, I discuss various consequences that it has with respect to the behavior of soft presuppositions in quantificational sentences, their interactions with scalar implicatures, and their effects on the licensing of negative polarity items. In chapter 5, I show that by looking at the interaction between presuppositions and scalar implicatures we can solve a notorious problem which arises with conditional sentences like (1) (Soames 1982, Karttunen and Peters 1979). The main issue with (1) is that it is intuitively not presuppositional and this is not predicted by any major theory of presupposition projection. (1) I’ll go, if you go too. Finally, I explore in more detail the question of which alternatives should we consider in the computation of scalar implicatures (chapter 6). Traditionally, the answer has been to consider the subset of logically stronger alternatives than the assertion. Recently, however, arguments have been put forward in the literature for including also logically independent alternatives. I support this move by presenting some novel arguments in its favor and I show that while allowing new alternatives makes the right predictions in various cases, it also causes an under- and an over-generation problem. I propose a solution to each problem, based on a novel recursive algorithm for checking which alternatives are to be considered in the computation of scalar implicatures and the role of focus (Rooth 1992, Fox and Katzir 2011). / Linguistics

Selon Asher (2013), la cohérence discursive force l’inférence de (1c) dans les exemples (1a)-(1b), expliquant ainsi l’(in)acceptabilité des exemples. (1) a. ‘John a un nombre pair d’enfants. Il en a 4.’ b. ‘ ? ?John a un nombre pair d’enfants. Il en a 3.’ c. +> John a n enfants et pas plus Nous avons tenté de déterminer si les implicatures nécessaires au maintien de la cohérence discursive sont systématiquement inférées en nous appuyant sur les théories de la RST et de la SDRT. Des tests linguistiques et la vérification du respect des contraintes sémantiques associées aux relations de discours ont mis en évidence deux catégories d’exemples contenant le quantificateur certains : ceux de type- RenfNA, dont les implicatures ne sont pas nécessaires à la cohérence et ceux de typeRenfA dans lesquels elles le sont. Nos tests ayant révélé que le renforcement est nécessaire dans les exemples de typeRenfA, nous avons conclu que les implicatures ne sont pas systématiquement inférées. Nous avons tenté d’apporter une explication à ce phénomène en effectuant des analyses de la structure discursive de nos exemples et avons démontré que dans les exemples de typeRenfNA, les relations de discours visent le constituant π∃ (certains), tandis que dans ceux de typeRenfA, le constituant π¬∀ (mais pas tous) est visé. Nos travaux ont démontré que les implicatures scalaires ne sont pas systématiquement inférées rendant parfois leur renforcement obligatoire. Nous avons également proposé un modèle à granularité fine prenant en compte la structure discursive et la pragmatique afin d’expliquer ce phénomène. / According to Asher (2013), discourse coherence forces the inference of (2c) in examples (2a)-(2b), thus explaining the (in)acceptability of these examples. (2) a. ‘John has an even number of children. He has 4.’ b. ‘??John has an even number of children. He has 3.’ c. +> John has n children and not more We attempted to determine whether the implicatures that are necessary to maintain discourse coherence are systematically inferred by drawing on the theories of RST and SDRT. Through linguistic tests and checking the respect of semantic constraints associated with discourse relations, we identified two categories of examples containing the quantifier some: typeRenfNA examples, in which implicatures are not necessary for discourse coherence, and typeRenfA examples in which they are. As our tests revealed that reinforcement is necessary in typeRenfA examples, we concluded that implicatures are not systematically inferred. We then attempted to explain this phenomenon. We performed analyses of the discourse structure of our examples and showed that in typeRenfNA examples, the discourse relations target the π∃ (some) constituent, while in typeRenfA examples, the π¬∀ (but not all) constituent is targeted. Thus, our work has shown that scalar implicatures are not systematically inferred, making implicature reinforcement sometimes mandatory. We also proposed a fine-grained model taking discourse structure and pragmatics into account to explain this phenomenon.