著者

細川 雄一郎

出版者

日本科学哲学会

雑誌

科学哲学 (ISSN:02893428)

巻号頁・発行日

vol.45, no.1, pp.17-33, 2012-07-30 (Released:2013-06-05)

参考文献数

12

被引用文献数

1

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It has been common to formalize counterfactuals (or subjunctive conditionals) in natural language in terms of a certain binary sentential connective, as in Stalnaker [12] and D. Lewis [8]. This paper suggests that another formalization by means of unary multi-modal operators is natural and appropriate for some counterfactuals. To see this naturalness and appropriateness, we observe an instance of transitive inference constituted of three counterfactuals in natural language, and formalize it by using expressive power of multi-modal logic, in particular Hennessy-Milner logic(HML) and Dynamic logic (DL). As a result, the instance of transitive inference turns out to be justified by the multi-modalized version of the most fundamental and familiar rules of modal logic, that is, the necessitation rule (NAct) and the axiom (KAct).

著者

細川 雄一郎

出版者

科学基礎論学会

雑誌

科学基礎論研究 (ISSN:00227668)

巻号頁・発行日

vol.47, no.1, pp.15-34, 2019 (Released:2019-11-07)

参考文献数

32

被引用文献数

1

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By applying the extended system of modal logic developed in [32], we present a logical analysis of the Gettier problem. Based on the result, in particular, we clarify the following point. In the literature on the Gettier problem, most authors seem to share the opinion that in general ‘belief’ precedes ‘knowledge’: we believe a proposition while we do not necessarily believe ourselves to have known it to be true. Interestingly, our analysis suggests that the story is the other way round in a sense: in general, for some proposition p, we believe that we have known that p, then we believe that p. Accordingly, even if given some reason for wanting to believe that p, we usually do not have the bare belief that p. Instead, in such a situation, more deliberately we think that it might be that p, or it can be hypothesized that p. Then, we can say, what we have at the start is not the bare belief that p, but “might possibility” or “hypothetical possibility” that p, which presumably involves abductive reasoning.

著者

細川 雄一郎

出版者

科学基礎論学会

雑誌

科学基礎論研究 (ISSN:00227668)

巻号頁・発行日

vol.47, no.1, pp.15-34, 2019

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<p>By applying the extended system of modal logic developed in [32], we present a logical analysis of the Gettier problem. Based on the result, in particular, we clarify the following point. In the literature on the Gettier problem, most authors seem to share the opinion that in general 'belief' precedes 'knowledge': we believe a proposition while we do not necessarily believe ourselves to have known it to be true. Interestingly, our analysis suggests that the story is the other way round in a sense: in general, for some proposition <i>p</i>, we <i>believe</i> that we <i>have known</i> that <i>p</i>, <i>then</i> we <i>believe</i> that <i>p</i>. Accordingly, even if given some reason for wanting to believe that <i>p</i>, we usually do <i>not</i> have the bare belief that <i>p</i>. Instead, in such a situation, more deliberately we think that <i>it might be that</i> <i>p</i>, or <i>it can be hypothesized that p</i>. Then, we can say, what we have at the start is <i>not</i> the bare belief that <i>p</i>, <i>but "might possibility"</i> or "hypothetical possibility" that <i>p</i>, which presumably involves <i>abductive reasoning</i>.</p>