Combining Texts

Ideas for 'works', 'On Interpretation' and 'Causation and Laws of Nature'

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3 ideas

5. Theory of Logic / D. Assumptions for Logic / 1. Bivalence
In talking of future sea-fights, Aristotle rejects bivalence [Aristotle, by Williamson]
     Full Idea: Unlike Aristotle, Stoics did not reject Bivalence for future contingencies; it is true or false that there will be a sea-fight tomorrow.
     From: report of Aristotle (On Interpretation [c.330 BCE], 19a31) by Timothy Williamson - Vagueness 1.2
     A reaction: I'd never quite registered this simple account of the sea-fight. As Williamson emphasises, one should not lightly reject the principle of bivalence. Has Aristotle entered a slippery slope? Stoics disagreed with Aristotle.
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
A prayer is a sentence which is neither true nor false [Aristotle]
     Full Idea: A prayer is a sentence which is neither true nor false.
     From: Aristotle (On Interpretation [c.330 BCE], 17a01)
5. Theory of Logic / D. Assumptions for Logic / 3. Contradiction
Contradiction is not a sign of falsity, nor lack of contradiction a sign of truth [Pascal]
     Full Idea: Contradiction is not a sign of falsity, nor the lack of contradiction a sign of truth.
     From: Blaise Pascal (works [1660]), quoted by A.George / D.J.Velleman - Philosophies of Mathematics Ch.6
     A reaction: [Quoted in Auden and Kronenberger's Book of Aphorisms] Presumably we would now say that contradiction is a purely formal, syntactic notion, and not a semantic one. If you hit a contradiction, something has certainly gone wrong.