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Unformatted text preview: if all its premises are true, its conclusion is true. Comment . The intuitive idea captured by this definition is this: If it is possible for the conclusion of an argument to be false when its premises are all true, then the argument is not reliable (that is, it is invalid). If true premises guarantee a true conclusion, then the argument is valid. Alternate formulation of the definition . An argument is VALID if and only if it is impossible for all the premises to be true while the conclusion is false. entailment Definition . When an argument is valid we say that its premises ENTAIL its conclusion. soundness Definition . An argument is SOUND if and only if it is valid and all its premises are true. Comment . It follows that all sound arguments have true conclusions. Comment . An argument may be unsound in either of two ways: it is invalid, or it has one or more false premises. Comment . The rest of this book is concerned with validity rather than soundness....
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This note was uploaded on 09/06/2010 for the course PHIL PHIL1006 taught by Professor Noprofonlinecourse during the Spring '08 term at HKU.
- Spring '08