Combining Texts

All the ideas for 'Conditionals', 'works' and 'Sources of Knowledge of Mathematics'

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7 ideas

4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
7791 The simplest of the logics based on possible worlds is Lewis's S5 [Lewis,CI, by Girle]
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
9545 Late in life Frege abandoned logicism, and saw the source of arithmetic as geometrical [Frege, by Chihara]
10. Modality / A. Necessity / 2. Nature of Necessity
11002 Equating necessity with informal provability is the S4 conception of necessity [Lewis,CI, by Read]
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
13768 Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington]
10. Modality / B. Possibility / 8. Conditionals / b. Types of conditional
13770 There are many different conditional mental states, and different conditional speech acts [Edgington]
10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals
13764 Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington]
13765 'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington]