Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-16T21:10:22Z No. of bitstreams: 1 SandersonMolickSilva_DISSERT.pdf: 786958 bytes, checksum: c978a9dfce670e09f4d33d627a246fc4 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-19T23:25:27Z (GMT) No. of bitstreams: 1 SandersonMolickSilva_DISSERT.pdf: 786958 bytes, checksum: c978a9dfce670e09f4d33d627a246fc4 (MD5) / Made available in DSpace on 2016-08-19T23:25:27Z (GMT). No. of bitstreams: 1 SandersonMolickSilva_DISSERT.pdf: 786958 bytes, checksum: c978a9dfce670e09f4d33d627a246fc4 (MD5) Previous issue date: 2015-09-04 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A Tese de Suszko ? uma posi??o filos?fica acerca da natureza dos m?ltiplos valores-de-verdade. Formulada pelo l?gico polon?s Roman Suszko, durante a d?cada de 1970, a tese defende a exist?ncia de ?apenas dois valores-de-verdade?. Tal afirma??o diz respeito ? concep??o de multi-valora??o perpetrada pelo l?gico Jan ?ukasiewicz. Considerado um dos criadores das l?gicas multi-valoradas, ?ukasiewicz acrescentou, em adi??o aos valores fregeanos tradicionais de Verdade e Falsidade, um terceiro valor: o Indeterminado. Para ele, seu terceiro valor poderia ser visto como um passo al?m da dicotomia Aristot?lica entre o ser e o n?o-ser. De acordo com Suszko, as ideias de ?ukasiewicz sobre multi-valora??o se baseavam em uma confus?o entre valores alg?bricos (aquilo que ? descrito/denotado por senten?as) e valores l?gicos (verdade e falsidade). Assim, o terceiro valor-de-verdade criado por ?ukasiewicz seria apenas um valor alg?brico, isto ?, uma poss?vel denota??o para uma senten?a, mas n?o um valor l?gico genu?no. A tese de Suszko encontra respaldo em um resultado formal conhecido hoje como Redu??o de Suszko, um teorema que afirma que toda l?gica tarskiana pode ser caracterizada por uma sem?ntica bivalente. Esta disserta??o pretende ser uma investiga??o da tese de Suszko e de suas implica??es. A primeira parte ? dedicada ?s ra?zes hist?ricas da multi-valora??o e introduz as principais motiva??es de Suszko ao formular a distin??o entre valores alg?bricos e valores l?gicos, e assim revelar o car?ter duplo dos valores-de-verdade. A segunda parte explora a Redu??o de Suszko e apresenta seus principais desenvolvimentos; as propriedades das sem?nticas bivalentes em compara??o ?s sem?nticas multi-valoradas tamb?m s?o exploradas e discutidas. Por fim, a terceira parte investiga o conceito de valores l?gicos dentro do contexto de no??es n?o-tarskianas de consequ?ncia l?gica; o significado da tese de Suszko dentro desses ambientes tamb?m ? discutido. Mais ainda, os fundamentos filos?ficos das no??es de consequ?ncias n?o-tarskianas s?o discutidos ? luz do debate recente sobre pluralismo l?gico. / Suszko?s Thesis is a philosophical claim regarding the nature of many-valuedness. It was formulated by the Polish logician Roman Suszko during the middle 70s and states the existence of ?only but two truth values?. The thesis is a reaction against the notion of many-valuedness conceived by Jan ?ukasiewicz. Reputed as one of the modern founders of many-valued logics, ?ukasiewicz considered a third undetermined value in addition to the traditional Fregean values of Truth and Falsehood. For ?ukasiewicz, his third value could be seen as a step beyond the Aristotelian dichotomy of Being and non-Being. According to Suszko, ?ukasiewicz?s ideas rested on a confusion between algebraic values (what sentences describe/denote) and logical values (truth and falsity). Thus, ?ukasiewicz?s third undetermined value is no more than an algebraic value, a possible denotation for a sentence, but not a genuine logical value. Suszko?s Thesis is endorsed by a formal result baptized as Suszko?s Reduction, a theorem that states every Tarskian logic may be characterized by a two-valued semantics. The present study is intended as a thorough investigation of Suszko?s thesis and its implications. The first part is devoted to the historical roots of many-valuedness and introduce Suszko?s main motivations in formulating the double character of truth-values by drawing the distinction in between algebraic and logical values. The second part explores Suszko?s Reduction and presents the developments achieved from it; the properties of two-valued semantics in comparison to many-valued semantics are also explored and discussed. Last but not least, the third part investigates the notion of logical values in the context of non-Tarskian notions of entailment; the meaning of Suszko?s thesis within such frameworks is also discussed. Moreover, the philosophical foundations for non-Tarskian notions of entailment are explored in the light of recent debates concerning logical pluralism.