The tradition of semantic externalism that follows Kripke (1972) and Putnam (1975) is built on the assumption that the folk have essentialist commitments about natural kinds. Externalists commonly take the body of empirical data concerning psychological essentialism as support for this claim. However, recent empirical findings (Malt, 1994; Kalish, 2002) call the psychological theory of essentialism into question. This thesis examines the relevance of these findings to both essentialism and semantic externalism. I argue that these findings suggest that these theories fail to reflect folk beliefs about natural kinds and folk natural kind term usage. This leads me to propose an alternative thesis-- the Ambiguity Thesis-- that is better able to accommodate the existing body of empirical data.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The semantic externalism was a philosophical view, formulated by Hilary Putnam, which claims that classificatory terms of one language depend, for their correct application, on collective endorsement (by the people who use them) and on the environment. Thus, the meaning of a term which designates a specimen or object depends, as a final criteria of decision in case of doubt, on specifications arising from specimen and object themselves. Hence, scientific determinations are fundamental. So, what adequately determines the reference of a term is not determined by the beliefs which an individual has concerning some object; the environment and other persons are the main factors which are the responsible for making what person says consistent with the object designated by the term used. Putnam s formulations have been read as essencialist, because he seems sometimes to say that natural kinds (gold, water etc.) are discriminated based on their intrinsic properties. What matters in semantics are the uses we make of general classificatory terms and as a delegate in the present state of our society, to others, the power to judge and recognize certain objects under which the laity have insufficient or no understanding. That said, it will be seen that externalists applications to specific sciences such as biology and chemistry are fruitless and that its application to the attempted right by some authors to be seen as a way out to solve historical problems of legal philosophy did not overcome the positivist matrix put forth by Herbert Hart. Concluding, I propose that, with the necessary adjustments, semantic externalism is compatible with Hart s semantic approach to law. / O externalismo semântico foi uma concepção filosófica, formulada por Hilary Putnam, que afirmava que termos classificatórios de uma linguagem dependem, para sua correta aplicação, do endosso coletivo (das demais pessoas que vivem em determinada comunidade) e do ambiente. Assim sendo, a correta aplicação de um termo que designa determinada espécime ou objeto dependeria, como critério último de decisão em caso de dúvida, das especificações oriundas da própria espécime ou objeto. Com isso, as determinações científicas são fundamentais. Logo, o que determina adequadamente a referência de um termo não são apenas as crenças que um indivíduo possui acerca de um determinado objeto; o ambiente e as demais pessoas são os grandes fatores responsáveis por endossar se as disposições de fala de um indivíduo estão condizentes com o objeto designado por ele com aquele termo empregado. As formulações de Putnam tenderam a ser vistas como essencialistas, na medida em que ele defendia que as espécies naturais (ouro, água etc.) seriam discriminadas com base em propriedades intrínsecas sem as quais deixariam de ser o que de fato são. Essa dissertação tem o objetivo de corrigir essas leituras e afirmar que o projeto semântico de Putnam visou reposicionar a semântica, colocando a noção de significado dentro do modo como fazemos juízos acerca do ambiente que nos circunda. O que importa em semântica são os usos que fazemos de termos classificatórios gerais e como delegamos, no estado atual de nossa sociedade, a terceiros, a competência de julgar e reconhecer determinados objetos sob os quais os leigos possuem uma compreensão insuficiente ou nula. Dito isso, se verá que as aplicações externalistas às ciências específicas como a biologia e a química são infrutíferas e que sua aplicação ao direito tentada por alguns autores como sendo vista como a saída para solucionar problemas históricos da filosofia jurídica não superaram a matriz positivista de Herbert Hart. Inclusive, proponho que, com os ajustes necessários, o externalismo semântico é compatível com a abordagem semântica de Hart ao direito.

The thesis comprises three foundational studies on the topics named in its title, together with an introduction. Ch. 1 argues against a popular combination of views in the philosophy of language: Propositionality, which says that the semantic values of natural language sentences (relative to contexts) are the propositions they express (in those contexts) and Compositionality, which says that the semantic value of a complex expression of a natural language (in a context) is determined by the semantic values its immediate constituents have (in that same context) together with their syntactic mode of combination. Ch. 1 argues that the Naïve Picture is inconsistent with the presence of variable-binding in natural languages. Ch. 2 criticizes the strategy of using “operator arguments” to establish relativist conclusions such as: that the truth values of propositions vary with time (Time Relativism) or that they vary with location (Location Relativism). Operator arguments purport to derive the conclusion that propositions vary in truth value along some parameter P from the premise that there are, in some language, sentential operators that operate on or “shift” the P parameter. I identify two forms of operator argument, offer a reconstruction of each, and I argue that both they rely on an implausible, coarse-grained conception of propositions. Ch. 3 is an assessment of the prospects for semantic internalism. It argues, first, that to accommodate Putnam’s famous Twin Earth examples, an internalist must maintain that narrow semantic content determines different extensions relative to agents and times. Second, that the most thoroughly worked out version of semantic internalism – the epistemic two-dimensionalism (E2D) of David Chalmers – can accommodate the original Twin Earth thought experiments but is refuted by similar thought experiments that involve temporally or spatially symmetric agents.