For the given premises P and Not P, is P a valid derivation? Shouldn't the

For the given premises P and Not P, is P a valid derivation? Shouldn't the

For the given premises P and Not P, is P a valid derivation? Shouldn't the derivation be true for all the premises for it to be valid or is it not sound and yet valid? But aren't we determining its unsoundness by virtue of something other than the content of those premises?

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