In the last module we set out a powerful argument for the radical skeptical conclusion, that knowledge is impossible. In this module, we will be considering some responses to this argument. We'll begin by examining the idea that we can appeal to common sense as a way of resisting skeptical conclusions. Next, we will look at a contextualized responses skepticism, which maintains that we can evade the skeptical problem by recognizing that knowledge is a context sensitive notion. Finally, we will explore the idea put forward by Vic Einstein, the very project of evaluating our beliefs on mass, as the radical skeptic proposes, is simply incoherent. Let's remind ourselves the radical skeptical puzzle. The following three claims are all independently plausible, but they can't all be true. The first, is that we're unable to know that a null is a radical skeptical hypotheses. The second is the closure principle, and the third is the claim that we have lots of knowledge of everyday propositions. How should we respond to this puzzle? One very natural response to philosophical problems like this, is to insist on our common sense principles and work back from there. If philosophy conflicts with common sense, then shouldn't the latter triumph over the former? One of the difficulties facing this approach however, is that the skeptical puzzle doesn't seem to rest, and I think barr common sense. That is, the three claims that we have noted as being inconsistent, all appear to rise out of our ordinary ways of thinking about knowledge. If that's right, then it seems that it is common sense itself, that is generating the skeptical problem. Indeed, that's precisely why the skeptical puzzle seems to be a paradox, in that, it is exposing a fundamental tension within our own ways of thinking about knowledge. Perhaps we can appeal to common sense in a different way. We don't normally consider radical skeptical hypotheses in everyday life, and everyday life is a default realm of common sense. So could we appeal to common sense to justify simply ignoring such hypotheses? The trouble with this suggestion however, is that we actually do sometimes consider radical skeptical hypotheses in everyday life, as the movies indicate. Moreover, that we don't ordinarily consider certain error possibilities, doesn't itself license us ignoring them if they are salient, and the radical skeptic, via her appeal to the closure principle, does seem to have made at least a prima facie case for their saliency. Here's another go at appealing to common sense. Radical skepticism as a position endorses one and two in the skeptical puzzle, and hence denies three. Can we just use three as a common sense foundation, from which to deny via two, one instead. Sure, we can explain how one could be false, but given this is a paradox, then denying any of these claims is going to lead to mystery. So why not this one? The thought would be, that there is a kind of impasse between these two approaches, with each of them evenly balanced against one another, but that appealing to common sense can break the deadlock. This approach gains some purchase on radical skepticism as a position, but not on radical skepticism as a paradox. Denying one rather than three probably is preferable from the perspective of common sense. But that only helps us explain why denying either of them is so counter-intuitive. This means that if we do want to deny one, then we'll need to explain why it is false, but given how very plausible one looks, how are we going to do that?