Rearranging words does not establish a valid contraposition. Truth preservation matters; otherwise a true premise could yield a false conclusion.
Quality means affirmation or negation and differs from quantity, which is universal or particular. A valid transformation may keep quality while altering quantity.
For example, under this traditional account a universal negative yields a particular negative: quality stays negative while quantity changes.
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Contraposition: Classical Rules, Validity and the Later Convention
Rearranging words does not establish a valid contraposition. Truth preservation matters; otherwise a true premise could yield a false conclusion.
Quality means affirmation or negation and differs from quantity, which is universal or particular. A valid transformation may keep quality while altering quantity.
For example, under this traditional account a universal negative yields a particular negative: quality stays negative while quantity changes.