Section 9.8-9.9

Section 9.8-9.9 - • An inconsistent set of premises...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Section 9.8-9.9 1. When you apply one of the replacement rules, the resulting statement must be a substitution instance of one of the statement forms for that rule 2. every line can have only one rule of inference as its justification 3. There can be multiple applications of a single replacement rule on the same line Invalid Argument True premises and a false conclusion A B C D A v D Therefore B v C A is F, B is F, C is F, D is T There are arguments where it is impossible to find all true premises In those cases the argument has inconsistent set of premises
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: • An inconsistent set of premises consists of both true premises and false premises o Argument will turn out valid o Have to have ALL true premises • Every deductive argument with an inconsistent set of premises is valid even if the conclusion bares no relation to the premises P1: today is Sunday P2: today is not Sunday C: my pet turtle is feeling nauseous Valid, but not sound Sound argument • A valid argument • With all true premises...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online