  This paper gives a formulation of quantum logic in the abstract algebraic
setting laid out by Dunn and Hardegree (2001). On this basis, it provides a
comparative analysis of viable quantum logical bivalent semantics and their
classical counterparts, thereby showing that the truth-functional status of
classical and quantum connectives is not as different as usually thought. Then
it points out that bivalent semantics for quantum logic - compatible with
realism about quantum mechanics - can be maintained, albeit at the price of
truth-functionality. Finally, but more importantly, the paper significantly
improves on Hellman's argument (1980) that this lack of truth-functionality
entails a change of meaning between classical and quantum connectives.
