Philosophical scepticism confronts us with very difficult conclusions. Scepticism about knowledge of the external world, for example, leads us to the conclusion that we have no knowledge of the world at all. Not only do we not have any knowledge of the world, but when presented with sceptical arguments it seems that knowledge becomes, in principle, unattainable. Scepticism's conclusions are seemingly ludicrous, but its arguments are often convincing and compelling.

Sceptical arguments leave us with bleak prospects for the possibility of knowledge, and in light of them it is easy to be led to pessimistic attitudes about knowledge; if scepticism is correct, we think and act as if we have knowledge when we do not and cannot have any. This leads many to draw a practical lesson about knowledge from scepticism; we cannot have knowledge, but we ignore sceptical arguments and act as if we have knowledge in order to fulfil practical goals. What we normally call knowledge is relegated to the role of pragmatic, but epistemically unjustified, assurances; saying 'I know' is just a way of convincing others to accept your case, and acting as if we know is just a practical necessity when action must be taken. The sceptical argument is taken at face value and applied directly to our epistemic situation in the world. The result is that we must make do with our decidedly lacking epistemic abilities.

I am unwilling to accept this pessimistic position, and I am not convinced that scepticism is quite as convincing as it appears to be. The pessimist sees sceptical conclusions as clashing badly with our common appraisals of knowledge, with scepticism having the last word; in common practice and everyday situations we think we have knowledge of the world, but scepticism tells us otherwise, and so much the worse for our everyday knowledge. I also believe that if the sceptic is correct, then there is a sincere clash between our everyday appraisals of knowledge and sceptical arguments. In everyday situations we believe we have all kinds of knowledge, yet scepticism tells us otherwise. But contrary to the pessimistic view, I contend that the clash between everyday knowledge and sceptical arguments is reason to question the sceptic's arguments as much as it is to bring judgment upon everyday knowledge. My goal is to try to determine whether sceptical arguments go wrong in some way. It is my position that they do, and that as such, sceptical arguments do not actually clash directly with everyday knowledge; the sceptical argument seems to bear directly on our everyday knowledge, but it actually fails to capture our common conception of knowledge, and so fails to apply to our epistemic position. Because of hidden assumptions or presuppositions, scepticism gets our epistemological position wrong.

It is easy to see why many are brought to the pessimistic position that we do not have any knowledge whatsoever. Scepticism, in its most convincing forms, works from what it claims is our everyday conception of knowledge, thus its conclusions reflect directly on our epistemic position. I hold that this is not the case; scepticism is in fact working with assumptions and presuppositions that we do not necessarily accept in our everyday epistemic practices. Also, many sceptical arguments have intuitive appeal; they are convincing without any knowledge of philosophical theories or complex argumentation. I believe that if we can isolate the assumptions and presuppositions of scepticism, it will lose its intuitive appeal. Michael Williams, in Unnatural Doubts, presents a very convincing argument along this line.

The purpose of this essay is to study philosophical scepticism, in order to reach a better understanding of its arguments. The hope is to find what assumptions and presuppositions, if any, sceptical arguments tacitly carry, in order to show that scepticism, contrary to reflecting badly on our everyday epistemic position in the world, does not actually reflect on us at all.