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Ideas for 'Lectures on the History of Philosophy', 'A Problem about Substitutional Quantification?' and 'Non-Monotonic Logic'

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3 ideas

5. Theory of Logic / G. Quantification / 4. Substitutional Quantification
The substitutional quantifier is not in competition with the standard interpretation [Kripke, by Marcus (Barcan)]
     Full Idea: Kripke proposes that the substitutional quantifier is not a replacement for, or in competition with, the standard interpretation.
     From: report of Saul A. Kripke (A Problem about Substitutional Quantification? [1976]) by Ruth Barcan Marcus - Nominalism and Substitutional Quantifiers p.165
5. Theory of Logic / K. Features of Logics / 10. Monotonicity
In classical logic the relation |= has Monotony built into its definition [Antonelli]
     Full Idea: In classical logic, Monotony follows immediately from the nature of the relation |=, for Γ |= φ holds precisely when φ is true on every interpretation on which all sentences in Γ are true.
     From: G. Aldo Antonelli (Non-Monotonic Logic [2014], 1)
     A reaction: That is, semantic consequence (|=) is defined in terms of a sentence (φ) always being true if some other bunch of sentences (Γ) are true. Hence the addition of further sentences to Γ will make no difference - which is Monotony.
Cautious Monotony ignores proved additions; Rational Monotony fails if the addition's negation is proved [Antonelli]
     Full Idea: Basic Monotony: something stays proved if further premises are added. Cautious Monotony: the addition of something which has been proved makes no difference. Rational Monotony: it stays proved as long as the addition's negation hasn't been proved.
     From: G. Aldo Antonelli (Non-Monotonic Logic [2014], 1)
     A reaction: [A compressed and non-symbolic summary]