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Unformatted text preview: ⊃ ( B ∨ C ) Argument ( ± ): B ≡ C ∼ B ∼ A P 1 . . . • P n is truthfunctionally valid iF no TVA makes P 1 , . . . P n true and C false. C • We can connect truthfunctional entailment with truthfunctional validity: In the deﬁnition of truthfunctional entailment, let Γ be { P 1 , . . . P n } , and let P be C. P 1 . . • Thus, P . n is valid iF { P 1 , . . . P n } truthfunctionally entails C. C • Prove that Argument ( ± ) is valid and that its premises truthfunctionally entail its conclusion by means of a truthtable. A B C MIT OpenCourseWare http://ocw.mit.edu 24.241 Logic I Fall 2009 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms ....
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 Fall '10
 DerekAllen
 Philosophy, Logic, Empty set, Material conditional, Propositional calculus, Philosophical logic

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