if the form is valid and the propositions true then it is sound. You can have a valid argument which isn't sound because one or both of the premises are false. Alternatively, you might have an invalid argument, that is the form is not correct, and a true conclusion, which would also be unsound... though true.
if the form is valid and the propositions true then it is sound. You can have a valid argument which isn't sound because one or both of the premises are false. Alternatively, you might have an invalid argument, that is the form is not correct, and a true conclusion, which would also be unsound... though true.