Contradictions, Logical Truths and Logical Validity | Logic I

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Contradictions, Logical Truths and Logical Validity

P $\lor{}$ ¬P is a \emph{logical truth}

logical truth defined p. 568

P $\land{}$ ¬P is a \emph{contradiction}

contradiction defined p. 564

Unlike say knowledge or truth, where it’s up to you to form a view of your own to a large extent, with logical validity there is a precise and clear definition that we are working with. Of course there are still questions about the nature of logical validity, but to get to those questions you first have to accept its definition.

4.1, 4.2

4.1, 4.2

4.12--4.16