 What’s the philosophical payoff if we join Williamson in rejecting KK on these grounds? Skeptical arguments that rely on KK might be disarmed. For example, a skeptic might argue that to know something, you must be able to rule out any competing alternatives. For example, to know the external world is real, you must be able to rule out the possibility that you are being deceived by Descartes’ demon (Stroud 1984). But then you must also be able to rule out the possibility that you don’t know the external world is real, since this is plainly an alternative to your knowing it is real. That is, you must \(K \neg\neg K\phi\), and thus \(KK\phi\) (Greco 2014). So the driving premise of this skeptical argument entails the KK thesis, which we’ve seen reason to reject.