新刊。Descriptionは以下の通り。
記号嫌いのあなたが初歩の初歩から学べるテキスト。この本をマスターする頃、あなたの論理感覚は確実に磨かれています。
本書は、文科系の学生が記号論理の考え方を理解し、スキルを習得できるようになることをめざす。内容を限定し、予備知識なしに学べるように工夫してある。第Ⅰ部命題論理学では、論理学とは何か、文の形式と意味、など、第Ⅱ部述語論理学では、文の内部構造、述語から文へ、等を順次学ぶ。
タブロー法と自然演繹を使った入門書。自然演繹はGentzen流。藤村先生の教育経験を生かしたつくりとなっており、巻末参考文献ページも親切。
- Almerindo E. Ojeda “Are Intensions Necessary? Sense as the Construction of Reference”
某有名なHPの新着の一つ。ちょっと長いかもしれないが、introの一部を記しておく。
More than half a century ago, Carnap (1947) defined the extension of an expression in a particular state of affairs as its reference in such a state, while construing the intension of an expression as a function that assigned, to each state of affairs, the extension of that expression in that state. He then considered taking the meaning of an expression to be its intension. The view that the meaning of an expression is its intension became the leading idea of possible-worlds semantics, an interpretive framework which soon became the foundation of the classic interpretation of modal logic (Kripke, 1959, 1963a, 1963b). Moreover, as shown in the large body of work emanating from the pieces collected in Montague (1974), the view that meaning is intension has shed light on many critical issues for the semantics of natural languages, and has become a cornerstone of that enterprise. Chief among these issues are the variable informativeness of identity statements, the failure of substitution in opaque contexts, the compositional interpretation of modal verbs and adverbs, the non-trivial nature of counterfactuals, and the nonsynonymy of vacuous predicates.
Yet, as Carnap himself realized, the identification of meaning and intension runs into serious difficulties when it attempts to interpret expressions that have the same intension yet differ in meaning.…
To solve these kinds of problems, Carnap (1947, §§14, 15) invoked a structural theory of meaning. As this theory would have it, the meaning of an expression φ is not the intension of φ, but rather the way in which the intension of φ is built out of the intensions of the constituents of φ.
…
It follows that the structural theory of meaning is strong enough to carry possible-worlds semantics over the wall of expressions which are cointensional yet nonsynonymous. The question thus arises as to whether the structural theory of meaning is strong enough to carry all of the weight possible-worlds semantics can carry—or whether a structural theory of meaning can dispense with intensions altogether. The purpose of this paper is to initiate an argument that it can.
