 Brogaard and Salerno (2002) develop other Fitch-like paradoxes against the restriction strategies. Note that Dummett’s knowability principle is a biconditional: \(p \leftrightarrow \Diamond Kp\), where \(p\) is basic. Tennant (2002) agrees that the knowability principle should preserve the factive nature of \(\Diamond\)K. So Brogaard and Salerno begin with the following strengthened knowability principle: