The author provides an outline of his argument in p. 11-12:
1.3 Outline of My Argument
I believe that these three forms of scepticism can be refuted by showing that the following four claims are true:
- I There is no good reason to believe that S never knows that p.
- II There are good reasons to believe that S sometimes knows that p.
- III There is a good argument for the claim that S sometimes knows that p.
- IV There are better reasons for believing that S sometimes knows that p than there are for believing that S never knows that p.
I take it that the conjunction of I and II provides the good argument referred to in III. That is, if I and II are true, then there is a good argument for the claim that S sometimes knows that p. Further, if III is known by S, S has the better reasons referred to in IV. For if I and II do provide S with a good argument for the claim that S knows that p, and if S knows that he/she has a good argument for that claim, then S has better reasons for believing that he/she sometimes knows that p than he/she has for believing that S never knows that p. Thus, Pyrrhonian Direct Scepticism will have been refuted.
Furthermore, if I is correct, there is no reason for accepting Direct Scepticism, and if II is correct, there are good reasons for rejecting it. And if IV is known by S (on the basis of having read this book, for example), Iterative Scepticism can be rejected. S may not know that he/she knows that p (because, for example, S does not believe that he/she knows that p) but S can know that he/she knows that p. For there is a good argument, knowable by S, for the claim that S sometimes knows that p. Thus, if S knows that p (and I through III show that there is a good argument for the claim that S sometimes does), and S knows that there is such a good argument, then S has all the evidence needed for the claim that he/she knows that p.
Thus, the core of my argument lies in showing that I and II are correct. That is the task of Chapter Two and Chapter Three respectively. I trust that after those chapters the argument strategy outlined above will become more clear.7
(IV) states that there are better reasons to believe that certainty is possible that there are to believe that certainty is not possible. Now, if there are better reasons to believe something, does it mean that that thing is true? Suppose my father goes to work every morning at 8 AM. My father went to work at 8 AM again today. So, I have a better reason to believe that my father went to work than I have to believe that he didn't go to work. But does it mean that it is impossible that my father didn't go to work today?
If it is not impossible, then has the author undermined scepticism at all through his argument?