Hein (407-408) states that Quine's method "...uses these (14) properties together with basic equivalences to determine whether a wff is a tautology, a contradiction, or a contingency." The idea is to substitute atoms in a propositional logic well-formed formula with true or false, and reduce it down to T or F which determines its truth meaning. I know how to do it, but the issue is: where does this come from? I've searched high and low across the internet to see where this originates, but all sources point back to the Hein book. Did he invent this? If so, why is it called Quine's method?