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Ideas for 'works', 'Axiomatic Theories of Truth' and 'Metaphysics: the logical approach'

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7 ideas

4. Formal Logic / E. Nonclassical Logics / 3. Many-Valued Logic
In Strong Kleene logic a disjunction just needs one disjunct to be true [Halbach]
     Full Idea: In Strong Kleene logic a disjunction of two sentences is true if at least one disjunct is true, even when the other disjunct lacks a truth value.
     From: Volker Halbach (Axiomatic Theories of Truth [2011], 18)
     A reaction: This sounds fine to me. 'Either I'm typing this or Homer had blue eyes' comes out true in any sensible system.
In Weak Kleene logic there are 'gaps', neither true nor false if one component lacks a truth value [Halbach]
     Full Idea: In Weak Kleene Logic, with truth-value gaps, a sentence is neither true nor false if one of its components lacks a truth value. A line of the truth table shows a gap if there is a gap anywhere in the line, and the other lines are classical.
     From: Volker Halbach (Axiomatic Theories of Truth [2011], 18)
     A reaction: This will presumably apply even if the connective is 'or', so a disjunction won't be true, even if one disjunct is true, when the other disjunct is unknown. 'Either 2+2=4 or Lot's wife was left-handed' sounds true to me. Odd.
4. Formal Logic / F. Set Theory ST / 1. Set Theory
Set theory attempts to reduce the 'is' of predication to mathematics [Benardete,JA]
     Full Idea: Set theory offers the promise of a complete mathematization of the 'is' of predication.
     From: José A. Benardete (Metaphysics: the logical approach [1989], Ch.13)
The set of Greeks is included in the set of men, but isn't a member of it [Benardete,JA]
     Full Idea: Set inclusion is sharply distinguished from set membership (as the set of Greeks is found to be included in, but not a member of, the set of men).
     From: José A. Benardete (Metaphysics: the logical approach [1989], Ch.13)
Every attempt at formal rigour uses some set theory [Halbach]
     Full Idea: Almost any subject with any formal rigour employs some set theory.
     From: Volker Halbach (Axiomatic Theories of Truth [2011], 4.1)
     A reaction: This is partly because mathematics is often seen as founded in set theory, and formal rigour tends to be mathematical in character.
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
The standard Z-F Intuition version of set theory has about ten agreed axioms [Benardete,JA, by PG]
     Full Idea: Zermelo proposed seven axioms for set theory, with Fraenkel adding others, to produce the standard Z-F Intuition.
     From: report of José A. Benardete (Metaphysics: the logical approach [1989], Ch.17) by PG - Db (ideas)
4. Formal Logic / G. Formal Mereology / 1. Mereology
Aristotle relativises the notion of wholeness to different measures [Aristotle, by Koslicki]
     Full Idea: Aristotle proposes to relativise unity and plurality, so that a single object can be both one (indivisible) and many (divisible) simultaneously, without contradiction, relative to different measures. Wholeness has degrees, with the strength of the unity.
     From: report of Aristotle (works [c.330 BCE]) by Kathrin Koslicki - The Structure of Objects 7.2.12
     A reaction: [see Koslicki's account of Aristotle for details] As always, the Aristotelian approach looks by far the most promising. Simplistic mechanical accounts of how parts make wholes aren't going to work. We must include the conventional and conceptual bit.