A redated post.
Reason, if there is such a thing, can serve as a court of appeal not only against the received opinions and habits of our community but also against the peculiarities of our personal perspective. It is something each individual can find with himself, but at the same time it has universal authority. Reason provides, mysteriously, a way of distancing oneself from common opinion and received practices that is not a mere elevation of individuality... not a determination to express one's idiosyncratic self rather than go along with everyone else. Whoever appeals to reason purports to discover a source of authority within himself that is not merely personal or societal, but universal... and that should also persuade others who are willing to listen to it. The Last Word (New York: Oxford University Press, 1997), pp. 3-4.
One way we might approach some of this is to ask whether reason in this sense exists, as I claim, it must if philosophical and scientific inquiry is to be truly possible, and second, what are the metaphysical implication of the existence of reason in this sense.