A novel analysis of knowledge is offered. The idea is to use the logic of presupposition and replace truth requirement with non-falsity requirement in the tripartite definition of knowledge. This move can be used to explain the difference between outdated knowledge and mere superstition and to solve some problems about the epistemic closure. In this regard, it is claimed that the present offer improves upon Nozick's conditional theory of knowledge and Dretske's relevant alternatives approach. Next, an attempt to elucidate Wittgenstein's and Wisniewski's anti-sceptical strategies is made. Finally, the prospects of avoiding circularities in reliabilism are indicated.