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Ideas for 'fragments/reports', 'Philosophy of Language' and 'Liberal Individualism and Liberal Neutrality'

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5 ideas

5. Theory of Logic / B. Logical Consequence / 5. Modus Ponens
8078 Modus ponens is one of five inference rules identified by the Stoics [Chrysippus, by Devlin]
     Full Idea: Modus ponens is just one of the five different inference rules identified by the Stoics.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by Keith Devlin - Goodbye Descartes Ch.2
     A reaction: Modus ponens strikes me as being more like a definition of implication than a 'rule'. Implication is what gets you from one truth to another. All the implications of a truth must also be true.
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
6023 Every proposition is either true or false [Chrysippus, by Cicero]
     Full Idea: We hold fast to the position, defended by Chrysippus, that every proposition is either true or false.
     From: report of Chrysippus (fragments/reports [c.240 BCE]) by M. Tullius Cicero - On Fate ('De fato') 38
     A reaction: I am intrigued to know exactly how you defend this claim. It may depend what you mean by a proposition. A badly expressed proposition may have indeterminate truth, quite apart from the vague, the undecidable etc.
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / a. Descriptions
15158 Indefinite descriptions are quantificational in subject position, but not in predicate position [Soames]
     Full Idea: The indefinite description in 'A man will meet you' is naturally treated as quantificational, but an occurrence in predicative position, in 'Jones is not a philosopher', doesn't have a natural quantificational counterpart.
     From: Scott Soames (Philosophy of Language [2010], 1.23)
5. Theory of Logic / F. Referring in Logic / 2. Descriptions / c. Theory of definite descriptions
15157 Recognising the definite description 'the man' as a quantifier phrase, not a singular term, is a real insight [Soames]
     Full Idea: Recognising the definite description 'the man' as a quantifier phrase, rather than a singular term, is a real insight.
     From: Scott Soames (Philosophy of Language [2010], 1.22)
     A reaction: 'Would the man who threw the stone come forward' seems like a different usage from 'would the man in the black hat come forward'.
5. Theory of Logic / G. Quantification / 7. Unorthodox Quantification
15156 The universal and existential quantifiers were chosen to suit mathematics [Soames]
     Full Idea: Since Frege and Russell were mainly interested in formalizing mathematics, the only quantifiers they needed were the universal and existential one.
     From: Scott Soames (Philosophy of Language [2010], 1.22)