Notice that our presentation of Fitch’s reasoning makes no explicit mention of the assumption that \(Kp \wedge \neg Kp\) is impossible. So here we attempt to pinpoint exactly where Fitch’s reasoning goes wrong on the above account. It is claimed at line 9 (in the first section of this entry) that \(K(p \wedge \neg Kp)\) is impossible. Of course \(K(p \wedge \neg Kp)\) entails the contradiction \(Kp \wedge \neg Kp\). And so, if the reasoning is that \(K(p \wedge \neg Kp)\) is impossible because c