[mmcdermott]

I would start with Plato. While the works are literary and not verbatim transcriptions of conversations, I think it gives a good view into the process of asking questions to dig into a point, then backtracking.

What you rapidly realize when applying this (as GP alludes to) is that most people simply aren't interested in the protracted examination of an idea. The challenge is to find people who are have interesting thoughts and the patience to work through it in depth.