 Brogaard and Salerno demonstrate other paradoxes against the restriction strategies. Those further results do not presuppose a commitment to the KK-principle. They hinge ultimately on the knowability theorist’s interpretation of \(\Diamond\). When \(\Diamond\) is metaphysical possibility or governed by a logic at least as strong as S4, the strong knowability principle (appropriately restricted), and taken as a necessary thesis, entails that there are no unknown truths. When \(\Diamond\) is epistemic possibility, and the knowability principle is treated as a necessary thesis that is known, the knowability principle entails that, necessarily, there are no undecided statements. Unlike the undecidedness paradoxes of Wright (1987), Williamson (1988), and Percival (1990), the reasoning provided by Brogaard and Salerno does not violate Tennant’s Cartesian restriction. A response to Brogaard and Salerno appears in Rosenkranz (2004). Further discussion of the Cartesian restriction appears in Brogaard and Salerno (2006, 2008). Tennant (2009) is a further development and defense of the Cartesian strategy. A defense of the restriction strategy appears in Fischer (2013).